exam 3 full version.txt

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exam 3 full version.txt
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bio 168 exam 3
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  1. What does the pectoral girdle include?
    Clavicle & scapula
  2. Anteriorly the medial end of each clavicle meets the?
    Sternum
  3. The distal end of each clavicle meets the ________ laterally
    scapulae
  4. Each clavicle is cone shaped at it medial Sternal end which attaches to the
    Sternal manubrium
  5. Each clavicle is flattened at its lateral Acromial end which articulates with the
    scapulae
  6. Scapulae is the?
    Shoulder blade
  7. Describe the superior border of the scapula
    is the shortest, sharpest boarder
  8. Describe the medial or vertebral border of the scapula
    parallels the vertebral column
  9. Describe the lateral or Axillary border of the scapula
    abuts the armpit and ends superiorly in a small shallow Fossa, the glenoid cavity
  10. Pertaining to the scapula: The superior scapular angle border meets the medial border at the
    superior angle
  11. Pertaining to the scapula: The lateral border meets at the
    lateral angle.
  12. Pertaining to the scapula: The medial and lateral boarders join at the
    inferior angle.
  13. The glenoid cavity fits what?
    Head of humerus
  14. The anterior or costal surface of the scapula is concave and relatively featureless. On the posterior surface there a prominent _________that is felt easily thought the skin.
    • spine
    • On the posterior surface of the scapula there is a spine that end laterally in an enlarged roughened triangular projection called the
    • Acromion
  15. The acromion articulates with the Acromial end of the
    Clavicle
  16. Projecting Anteriorly from the superior scapular border is the
    Coracoids process �little finger bent�
  17. The coracoid process helps anchor the biceps muscle of the arm. It is bounded by the ________medially and by the glenoid cavity laterally.
    Suprascapular notch
  18. The_____________and __________ fossae are inferior and superior respectively to the spine.
    infraspinous and supraspinous
  19. The __________is the shallow concavity formed by the entire anterior scapular surface.
    subscapular fossa
  20. Infraglenoid tubercle is located where?
    Bottom of the glenoid cavity
  21. Supraglenoid tubercle is located where?
    Top of the glenoid cavity
  22. The______, the sole bone of the arm, is a typical long bone. The largest, longest bone of the upper limb, it articulates with the scapula at the shoulder and with the radius and ulna at the elbow.
    Humerus
  23. A the proximal end of the humerus is its smooth, hemispherical ________, which fits into the glenoid cavity of the scapula in a manner that allows the arm to hang freely at ones side.
    Head
  24. Immediately Anteriorly inferior to the head is a slight constriction called the
    Anatomical neck
  25. Just inferior to the anatomical neck on the lateral side is the
    Greater tubercle
  26. Just inferior to the anatomical neck medially is the
    • lesser tubercle.
    • The greater tubercle and the lesser tubercle are separated by the
    • Intertubercular Sulcus or bicipital grove
  27. Just distal to the tubercles is the
    Surgical neck
  28. About midway down the shaft on its lateral side is the
    Deltoid tuberosity
  29. Nearby the deltoid tuberosity is the _________ which runs obliquely down the posterior aspect of the shaft, marking the course of the radial nerve.
    Radial grove
  30. At the distal end of the humerus are two condyles. A medial ______, which looks like an hourglass on its side, and the lateral ball-like _______.
    • Trochlea
    • capitulum
  31. The trochlea articulates with the
    Ulna
  32. The capitulum articulates with the
    Radius
  33. Both of the epicondyles (trochlea and capitulum) are flanked by the
    Medial and lateral epicondyles
  34. The ulnar nerve which runs behind the _________ is responsible for the tingling sensation you experience when you hit your �funny bone�
    Medial epicondyle
  35. Superior to the trochlea on the anterior surface is the___________, and on the posterior surface is the_______.
    • Coronoid fossa
    • Olecranon fossa
  36. A small________, lateral to the coronoid fossa receives the head of the radius when the elbow is flexed.
    radial fossa
  37. The proximal ends of the ulna and radius articulate with the
    Humerus
  38. The distal end of the ulna and radius articulate with the
    Wrist
  39. The radius and ulna are connected along their entire length by
    Interosseus membrane
  40. In the anatomical position, the radius lies_________ and the ulna __________.
    • laterally (the thumb side)
    • medially (pinky side)
  41. The ulna has two prominent processes
    Olecranon (elbow) and coronoid process
  42. The olecranone and the coronoid processes are separated by a deep concavity, the _____.
    Trochlear notch
  43. On the lateral side of the coronoid process is a small depression, the _________, where the ulna articulates with the head of the radius.
    Radial notch
  44. Distally he ulnar shaft narrows and ends in a knoblike
    Head
  45. Medial to the ulnar head is the _______, from which a ligament runs to the wrist.
    Styloid process
  46. The radius is thin at its proximal end and wide distally, the opposite of the ulna. The ______of the radius is shaped somewhat like the head of a nail. The superior surface of it is concave and articulates with the capitulum of the humerus.
    Head
  47. Medially, the head articulates with the ______of the ulna.
    radial notch
  48. Just inferior to the head of the radius and the radius neck is the
    Radial tuberosity
  49. Distally, where the radius is expanded it has a medial
    Ulnar notch
  50. The ulnar notch articulates with the ulna and a lateral
    Styloid process
  51. The skeleton of the had includes the bones of the
    • Carpus (wrist)
    • Metacarpus (palm)
    • Phalanges (bones of fingers)
  52. The carpus consist of eight marble sized short bones or ____closely united by ligaments
    Carpals
  53. The carpals are arranged in two irregular rows of four bones each. In the proximal row (lateral to medial) are the:
    • Scaphoid (boat shaped)
    • Lunate (moon like)
    • Triquetrium (triangular)
    • Pisiform (pea shaped)
  54. Only the _____ and ____ articulate with the radius to form the wrist joint
    Schapoid and lunate
  55. The carpals of the distal row (lateral to medial) are the:
    • Trapezium (little table)
    • Trapezoid (four sided)
    • Capitates (head-shaped)
    • Hamate (hooked)
  56. Metacarpus is the
    Palm
  57. How many metacarpals?
    5
  58. How are the metacarpals numbered?
    1-5 from thumb to pinky
  59. The bases of the metacarpals articulate with the ________ proximally and each other medially and laterally. Their bulbous heads articulate with the proximal _______of the fingers.
    • Carpals
    • Phalanges
  60. The fingers of digits of the upper thumb are numbered 1 to 5 beginning with the thumb or pollex. In most people the third finger is the longest. Each finger has three phalanges:
    • Distal, middle and proximal
    • The thumb does not have which phalanx?
    • Middle
  61. How many bones in phalanges?
    14
  62. The _______ attached to the lower limbs to the axial skeleton, transmits the full weight of the upper body to the lower limbs and supports the visceral organs of the pelvis.
    Pelvic girdle
  63. The pelvic girdle is formed by a pair of hip bones called an
    Os coxae or Coxal bone
  64. The point of fusion of the ilium, ischium and the pubis is a deep hemispherical socket called the
    Acetabulum
  65. The ________ receives the head of the femur or the thigh bone, at this hip joint.
    Acetabulum
  66. The _____ is a large flaring bone that forms the superior region of the coxal bone.
    Ilium
  67. The _____ is where you rest your hands on your hips.
    Iliac crest
  68. Each iliac crest ends anterior in a blunt
    anterior superior iliac spine.
  69. Each iliac crest ends posteriorly in a sharp
    posterior superior iliac spine
  70. Inferior to the anterior superior iliac spine is the
    Anterior inferior iliac spine
  71. Inferior to the posterior superior iliac spine is the
    Posterior inferior iliac spine
  72. Just inferior to the posterior inferior iliac spine, the ilium indents deeply to form the
    Greater sciatic notch
  73. The medial surface of the ilium exhibits a concavity called the
    • Iliac fossa
    • Posterior to iliac fossa is the roughened
    • Articular surface �ear shaped�
  74. The _______forms the posteroinferior part of the hip bone.
    Ischium
  75. Roughly L or arc-shaped it has a thicker superior body adjoining the ilium and a thinner inferior
    Ischial ramus
  76. The ischial ramus joins the ______ anteriorly.
    Pubis
  77. The ______ projects medially into the pelvic cavity
    Ischial spine
  78. Just inferior to the ischial spine is the
    Lesser sciatic notch
  79. The inferior surface of the ischial body is rough and grossly thickened as the
    Ischial tuberosity
  80. The _____ forms the anterior portion of the hip bone.
    Pubis
  81. Escentiallly the pubis is V shaped with __________and ___________ issuing from its flattened medial body.
    Superior and inferior rami
  82. The anterior border of the pubis is thickened to form the
    Pubic crest
  83. The large opening in the hip bone is the
    Obturator foramen
  84. The bodies of the two pubic bones are joined by a fibrocatilage disc, forming the midline_______.
    Pubic symphasis.
  85. The _____ is the single bone of the thigh, it is the largest, longest and strongest bone in the body.
    Femur
  86. The ball like ____ of the femur has a small central pit called the ______.
    • Head
    • Fovea capitus
  87. The head of the femur is carried on a _______ that angles laterally to join the shaft.
    Neck
  88. At the junction of the shaft and neck are lateral ____________ and posteromedial ________.
    • Greater trochanter
    • Lesser trochanter
  89. The two trochaners are connected by the _______________Anteriorly and by the prominent _______posteriorly.
    • Intertrochantic line
    • Intertrochantric crest
  90. Inferior to the intertrochantric crest on the posterior shaft is the __________ which bends into a long vertical ridge the ________________________ inferiorly.
    • Gluteal tuberosity
    • Linea aspera
  91. Distally, the femur broadens and end in a wheel-like _______and ______, which articulate with the tibia of the leg
    Lateral and medial condyles
  92. The ____________and __________ flank the condyles superiorly.
    medial and lateral epicondyles
  93. On the superior part of the medial epicondyle is a bump, the
    Adductor tubercle
  94. The smooth ________________, between the condyles on the anterior femoral surface, articulates with the patella.
    Patellar surface
  95. Between the condyles on the posterior aspect of the femur is the deep, U-shaped _________.
    Intercondylar fossa
  96. The two parallel bones, the tibia and fibula form he skeleton of the leg, the lower limb between the knee and ankle. These two bones are connected by ____________ and articulate with each other proximally and distally.
    Interosseious membrane
  97. The ____ is the shinbone, which receives the weight of the body from the femur and transmits it to the foot.
    Tibia
  98. At its broad proximal end are the concave _____ and ______, which look like two huge checkers laying side by side.
    Medial and lateral condyles
  99. The medial and lateral condyles of the tibia are separated by an irregular projection, the
    Intercondylar eminence
  100. Just inferior to the condyles, the tibia�s anterior surface displays the rough ________, to which the patellar ligament attaches.
    Tibial tuberosity
  101. Distally the tibia is flat where it articulates with the _____ bone of the foot.
    Talus
  102. The ________ forms the medial bulge of the ankle.
    Medial malleolus
  103. The _______, on the lateral surface of the tibia, participates in the distal tibiofibular joint.
    Fibular notch
  104. The ______ is a sticklike bone with slightly expanded ends. It articulates proximally and distally with the lateral aspects of the tibia.
    Fibula
  105. The proximal end of the fibula is its
    Head
  106. The distal end of the fibula is the
    Lateral malleolus
  107. Inferior to the talus is the
    Calcaneus
  108. The top part of the patella is the
    Base
  109. The bottom part of the patella is the
    Apex
  110. The _________ of the patella articulates with the femur.
    Articular surface
  111. The skeleton of the foot includes the bones of the
    • Tarsus
    • Metatarsals
    • Phalanges
  112. The tarsus is made up of 7 bones called
    Tarsals
  113. The talus is the _____ which articulates with the tibia and fibula superiorly and the strong ______ which form the ____ of the foot and carries the talus on the upper surface.
    • Ankle
    • calcaneus
    • heel
  114. The tarsals include:
    Cuboid, navicular, medial cuneiform, intermediate cuneiform and lateral cuneiform.
  115. The cuboid and cuneiform bones articulate with the _____________ anteriorly.
    Metatarsal bones
  116. The metatarsus consists of 5 small long bones called ________ numbered 1-5 beginning with the big toe side.
    Metatarsals
  117. There are 14 phalanges of the toes. There are three phalanges in each digit except the
    Hallux which only has proximal and distal
  118. The 3 phalanges are named as?
    Proximal, middle and distal.
  119. The arches of the foot are?
    Articular angles of the tarsals and metatarsals
  120. What does the medial longitudinal arch consist of?
    Calcaneous , talus, navicular, 1-3 cuneiforms and the 1st three metatarsals
  121. What does the lateral longitudinal arch consist of?
    Calcaneus, cuboid, and 1-3 cuneiforms
  122. What does the transverse arch consist of
    Base of metatarsals, cuboid, and 1-3 cuneiforms
  123. The arches of the foot are supported by
    Ligament ands some muscular and tendon support
  124. What do the arches do for the body?
    Distribute weight evenly between the heel and the metatarsals.
  125. Flat feet are a result of?
    1 or more fallen arches due to excessive strain on tendons and ligaments.
  126. What is an articulation?
    • Joint
    • Any junction between 2 components of the skeleton; bone-bone, bone-cartilage, bone-teeth
  127. Joints are classified by
    Structure and function
  128. Name the three kinds of joints
    • Fibrous joint
    • Cartilaginous joint
    • Synovial joint
  129. Describe the fibrous joint
    No cavity; fibrous CT
  130. Describe the cartilaginous joint
    No cavity; cartilage
  131. Describe he synovial joint
    Synovial cavity present; articular capsule
  132. What does joint function mean?
    Degree of movement
  133. Name the three kinds of functions for joints
    • Synarthrosis
    • Amphiarthrosis
    • Diarthrosis
  134. Synarthrosis
    Immovable
  135. Amphiarthrosis
    Slightly movable
  136. Diarthrosis
    Freely movable
  137. Name the specific types of fibrous joints
    • Sutures
    • Syndesmosis
    • Gomphosis
  138. Describe a suture
    Immovable; short CT; sagital suture
  139. Describe syndesmosis
    • Slightly movable (to �immovable with give�);
    • Degree of movement depends on length of CT fibers;
    • Distal tibiofibular joint
  140. Gomphosis
    • Immovable; teeth in socket;
    • Periodontial ligament (short CT)
  141. What are the specific types of cartilaginous joints?
    • Synchondrosis
    • Symphasis
  142. Describe snchondrosis
    • Immovable;
    • Hyaline cartilage;
    • Epiphyseal plate and sternum and rib 1
  143. Describe symphasis
    • Slightly movable;
    • Fibrocartilage;
    • Pubic symphasis
  144. ______are those in which the articulating bones are separated by a fluid-containing joint cavity.
    • Synovial joints
    • glassy-smooth hyaline cartilage covers the opposing bone surfaces in a synovial joint as
    • articular cartilage
  145. The joint cavity is enclosed by two layers articular capsules, or joint capsules. The external layer is a ________.
    Fibrous capsule
  146. The fibrous capsule attaches to the
    periosteum
  147. The synovial membrane is formed by
    Loose CT, elastic fibers and adipocytes
  148. The synovial membrane produces
    Synovial fluid
  149. The synovial fluid functions include?
    Lubrication of the joints and nourishes the cartilage
  150. The intrinsic ligament is what and does what?
    • Thickenings of the articular capsule
    • Stabilizes the joint
  151. The extra capsular ligament occurs where?
    Outside the articular capsule and help stabilize the joint
  152. Articular discs or cartilages (fibrocartilages), or menisci do what?
    Extend inward from the articular capsule and partially or completely divide the synovial cavity into two, channel the flow of synovial fluid and allow for variations in articular surface shapes.
  153. The labrum (fibrocatilage) � glenoid labrum do what?
    Deepens the articular surface of the bones
  154. What are the determinants of synovial joint movement?
    • Structure or shape of articulating surface
    • Strength and tension (tautness) of the joint ligaments
    • Muscle arrangements and tension
    • Apposition of soft parts
    • Hormones
  155. Flexion
    Bending or decreasing the angle between bones or parts
  156. Extension
    Straightening of bent part of increasing the angle between bones or parts
  157. Supination
    • Rotates radius laterally around its long axis
    • Palms faces anterior
  158. Pronation
    • Rotates radius medially around its long axis
    • Palm faces posteriorly
  159. Dorsiflexion
    Upward movement of the foot or toes
  160. Plantarflexion
    Downward movement of the foot or toes
  161. Eversion
    Turning the plantar surface of the away from the median plane
  162. Inversion
    Turning the plantar surface of the foot toward the median plane
  163. Abduction
    • Movement of the digits away from the median plane
    • (spread fingers or toes apart)
  164. Adduction
    • Movement of the digits toward the median plane
    • (Bring fingers or toes together)
  165. Rotation
    Revolving of a part around its long axis
  166. Lateral rotation/external rotation
    Rotation away from the median plane
  167. Medial rotation/internal rotation
    Rotation toward the median plane
  168. Protraction
    Anterior of forward movement of the mandible
  169. Retraction
    Posterior of backward movement of the mandible
  170. Elevation
    Lifting, raising or moving a part (mandible ) superiorly
  171. Depression
    Lowering or moving a part (mandible) inferiorly
  172. Glide
    Side to side or back and forth
  173. Circumduction
    Movement if the body to create a �cone� in space
  174. Bilateral contraction
    Both side contraction
  175. Unilateral contraction
    One side contraction
  176. Bone; Articulating bones; Structural type; functional type; Distal tibiofibular joint
    • Tibia and fibula
    • Fibrous; syndesmosis
    • Amphiarthrosis
  177. Bone; Articulating bones; Structural type; functional type; Intervertebral joint
    • Between adjacent centra
    • Cartilaginous; symphasis
    • Amphiarthrosis
  178. Bone; Articulating bones; Structural type; functional type; Pubic symphasis
    • Pubic bones
    • Cartilaginous; symphasis
    • Amphiarothisis
  179. Bone; Articulating bones; Structural type; functional type; skull
    • Cranial and facial bones
    • Fibrous; suture
    • Synarthrosis
  180. Bone; Articulating bones; Structural type; functional type; Sternalcostal joint
    • Sternum and rib 1
    • Cartilaginous; synchondrosis
    • Synarthrosis
  181. Bone; Articulating bones; Structural type; functional type; �The rest are�
    Synovial and diarthrosis
  182. Function of muscles?
    • Motion
    • Maintain posture
    • Stabilize joints
    • Generate heat
  183. Muscles have properties of ?
    Excitability
  184. What is excitability?
    Ability to receive and respond to stimuli
  185. What is a stimulus?
    Environmental change that is strong enough to initiate an action potential
  186. What is contractility?
    Ability to shorten
  187. What is extensibility?
    Ability to stretch when opposing muscles contract (antoginistic)
  188. What is elasticity?
    Ability to return to their original shape
  189. Describe skeletal muscle tissue
    Long cylindrical cells; Multi nucleated cells; Nucleus is peripherally placed; cross striations are obvious;
  190. What are the functions of skeletal muscle tissue?
    Voluntary movement ; Locomotion; manipulation of environment; facial expression; voluntary control.
  191. What is the location of skeletal muscle tissue?
    Attaches to bones
  192. Describe cardiac muscle tissue
    Branching, striated, generally uninucleated cells that interdigitate at specialized junctions (intercalated discs)
  193. What is the function of cardiac muscle?
    As it contracts it propels blood into the circulation; involuntary control.
  194. What is the location of cardiac muscle?
    The walls of the heart
  195. Describe smooth muscle.
    Spindle-shaped cells with central nuclei; no striations; cells arranged closely to form sheets.
  196. What is the function of smooth muscle?
    Propels substances or objects (foodstuffs, urine, a baby) along internal passageways; involuntary control.
  197. What is the location of smooth muscle cells?
    Mostly in the walls of hallow organs.
  198. Bone formation and bone growth begins approximately the
    6th or 8th week of development
  199. Bone formation andbone growth involves a replacement of
    Pre-existing connective tissue
  200. What are the two pre-existing connective tissues
    Mesenchyme and cartilage
  201. What are the two methods of osteogenesis?
    • Intermemranous bone formation
    • Endochondral bone formation
  202. Intermembranous bone formation is directly within
    A membrane of primitive CT (mesenchyme)
  203. Endochondrial bone formation is a
    Replacement of pre-existing cartilage
  204. Intermembranous bone formation is when a bone forms
    Within a fibrous CT membrane
  205. What are some examples of intermembranous bone formation?
    • Flat bones of skull
    • Clavicles
  206. The precess of intermembranous bone formation begins where?
    In a membrane of mesenchyme
  207. In the process of the intermembranous bone formation he groups of mesenchmal cells differentiate into
    Osteoblats
  208. The area where the groups of mesenchmal cells differentiate into osteoblasts id called the
    Primary ossification center
  209. Osteoblasts secrete
    Osteoid
  210. What is osteoid?
    Calcium and other minerals
  211. This osteoid becomes?
    Mineralized matrix
  212. Osteoblasts become
    Osteocytes
  213. Still in the process of intermembranous bone formation, more osteoblasts are formed and they continue to secrete osteoid. This forms what?
    Irregular plates of bone tissue
  214. The irregular plates of bone tissue fuse together and this is the first what? Then what?
    Immature one then spongy bone
  215. This area of spongy bone is richly what? And what cells are present here?
    • Vascularized.
    • Bone marrow
  216. Once the bone marrow cells move in, what forms?
    Periosteum and endosteum
  217. Once the periosteum and endosteum are formed what happens?
    Surface layers of spongy bone are remodeled into compact bone.
  218. Endochondral bone formation occurs where?
    Within a hyaline cartilage model of the bone
  219. By which method do most bones form?
    Endochondrial bone formation
  220. What gives rise to the hyaline cartilage model?
    Mesenchyme
  221. Once there is a hyaline cartilage model, what happens next?
    Blood vessels pierce the perichondrium
  222. Once the hyaline cartilage is in place, blood vessels are formed, what happens next?
    Some perichondrial cells are stimulated to become osteoblasts (which secrete osteiod)
  223. Once hyaline cartilage is in place, blood vessels are formed, perichondial cells become osteoblasts, what forms next?
    Bone collar. Which is covered by periosteum.
  224. Deep to the bone collar what forms?
    Primary ossification center.
  225. Many changes occur once the primary ossification center is in place. What happens to the chondrocytes?
    • 1. They become large, accumulate glycogen & enzymes
    • 2. They die and rupture; There are now empty lacunae; cartilage matrix calcifies
    • 3. Calcified cartilage matrix prevents diffusion of nutrients and there for other chondrocytes die; calcified cartilage matrix degenerates; primary marrow spaces form (will enlarge to form the marrow cavity)
    • 4. Blood vessels grow along these marrow spaces and bring osteogenic cells with them
    • 5. Changes continue toward other epiphyses from the primary ossification center
  226. What happens in the resting zone (zone of reserve cartilage) for endochondrial bone formation?
    Hyaline cartilage. Function to anchor plate to bone of epiphysis; Reserve source of new cells.
  227. What happens in the zone of proliferation for endohondrial bone formation?
    Mitosis of chondrocytes; increases length of model aand replace cells that die
  228. What happens in the zone of hypertrophy (endochondrial bone formation)?
    Mitosis stops and chondrocytes enlarge
  229. What happens ins the zone of calcification for endochondrial bone formation?
    Chondrocyes die; cartilage matrix calcifies
  230. What happens in the zone of ossification for endochondrial bone formation?
    Osteoblasts and osteoclasts are present; endosteum forms; bone marrow cells move in.
  231. The bone collar continues to grow. The marrow cavity continues to enlarge. The series of changes in the epiphyseal plate continue. Now what happens?
    Blood vessels enter the epiphysis
  232. Once the blood vessels enter the epiphysis what happens?
    The secondary ossification center forms; the process repeats itself � radial growth
  233. Cartilage will be replaced by bone everywhere except?
    • Articular surface (no perichondium therefore no bone collar)
    • Epiphyseal plate (for a time)
  234. When bone stops growing, the epiphhyseal plate becomes ?
    The epiphyseal line
  235. The diaphyseal shaft increases in length primarily as a result of ?
    The epiphyseal plate
  236. Long bone gets wider as a result of the apposition of bone by the
    Periosteum
  237. Growth is associated with:
    • Partial removal (resorption) of performed tissue
    • Deposition of new tissue
  238. When the epiphyseal plate stops growing:
    • No more longitudinal growth
    • Reserve cartilage is replaced by bone (and epiphyseal line is formed)
  239. Remodeling is a continual event which replaces old tissue with new tissue. Which involves?
    Resorption and deposition
  240. What are the functions of remodeling?
    • Replaces warn or injured bone tissue with new;
    • Exchanges minerals Ca++ bone with ?? blood
  241. Resorption of bone tissues is through
    Osteoclasts
  242. What is the process of resorption of bone tissue?
    • Proteolytic enzymes
    • Acids
    • Howships�s lacuna
  243. Describe proteolytic enzymes
    Digest collagen and other organic substances
  244. Describe acids
    May soluablize minerals
  245. Describe howship�s lacuna
    Site of active bone resorption
  246. Parathyroid hormone..causes?
    • Osteoclasts activity and numbers to increase
    • Released from the parathyroid glans when blood calcium levels get too low
    • The end result with the increase in bone resprption will increase blood calcium levels and increase enough to go back to normal range
    • Deposition of bone tissues involves?
    • Osteoblasts
    • Calcitonin
    • Decreased osteoclasts activity
    • Increased osteoblast activity
    • Matrix formation and calcium deposition increases as new bone is formed.
    • Released from the thyroid gland when the calcium levels get to high in the blood
    • The end result is increased bone deposition and decreased calcium levels in the blood
  247. What is a fracture?
    Structural discontinuity or break in a bone � caused by trauma or physical force
  248. How are fractures classified?
    • Amount of discontinuity
    • Skin intregrity
    • Angle of the break
    • Alteration in alignment
  249. Amount of discontinuity?
    • Complete
    • Incomplete or partial
  250. What is complete ?
    Broken into two separate places
  251. What is incomplete or partial?
    Broken incompletely
  252. Skin integreity?
    • Simple or closed
    • Compound or open
  253. What is simple or closed?
    Doesn�t break thought the skin
  254. What is compound or open?
    Broken ends protrude thougth the skin
  255. Angle of the break?
    • Transverse
    • Spiral
    • Oblique
  256. What is transverse?
    At right angle to long axis
  257. What is spiral?
    Twisted apart
  258. What is oblique?
    At an angle (other then 90) across the bone
  259. Alteration in alignment?
    • Nondisplaced
    • Displaced
    • Comminuted
  260. What is nondisplaced ?
    Anatomical alignment preserved
  261. What is displaced?
    Anatomical alignment not preserved
  262. What is comminuted?
    Splintered at the sight of impact with fragments between two main pieces
  263. Setting the fracture =?
    Reduction
  264. What does reduction mean in fracture resetting?
    Making sure the bones are put in and held in proper alignment
  265. What is closed reduction?
    Without exposing the bones though surgery
  266. What is open reduction?
    Surgical exposure of bones to put back into alignment
  267. Formation of a fracture hematoma?
    Blood vessels at fracture site disrupted; blood accumulates as a fracture hematoma; with in 6-8 hours
  268. Fibrocartilagenous callus formation involves?
    • Capillaries regrow into the area
    • Phagocytic cells clean-up
  269. Periosteum and endosteum around the fracture site responds with:
    • � Proliferation of fibroblasts
    • � Differentiation of some fibroblasts into chondroblasts
    • � Osteoblasts migrate into the fracture site
    • � Mass of repair tissue = fibrocartilaginous callus (area with collage, cartilage and bone)
  270. Proliferation of fibroblasts:
    Forms a cellular tissue around the fracture and between the broken ends
  271. Differentiation of some fibroblasts into chondroblasts:
    Secrete cartilage matrix
  272. Osteoblasts migrate into the fracture site:
    Form spongy bone
  273. Mass of repair tissue =
    fibrocartilaginous callus (area with collage, cartilage and bone)
  274. bony callus formation:
    • 1. Osteoblasts in the more vascularized areas begin to form spongy bone
    • 2. Trabeculae gradually fuse
    • 3. Fibrocartilage is converted into spongy bone
  275. Bone remodeling
    • � Dead tissue is removed
    • � Trabeculae are molded into compact bone
    • � Original bone structure is restored
  276. Epimysium
    �outside the muscle� overcoat of dense irregular CT that surrounds the whole muscle. Deep fascia.
  277. Endomysium
    �within the muscle� sheet of CT that surrounds individual muscle fibers
  278. Perimysium
    Layer of fibrous CT that surrounds each fascicle
  279. Fascicle
    • A bundle of muscle fibers
    • Sarcoplasm
    • Cytoplasm of the muscle cell
  280. Sarcoplasm reticulum
    Endoplasmic reticulum of muscle cell
  281. Sarcolemma
    Plasma membrane of muscle cells
  282. Myofibril
    Rod like contractile elements that occupy most of the muscle cell volume. Composed of sarcomeres arranged end to end.
  283. Sarcomere ?
    • The smallest contractile unit
    • Structural and functional unity of skeletal muscle
  284. What is a striation?
    Repeating series of light and dark bands
  285. What are the dark bands called?
    A-Bands
  286. What are the light bands called ?
    I-bands
  287. The dark A band has a lighter region in its mid section called?
    H zone
  288. Each H zone is bisected vertically by a dark line called the?
    M line
  289. The Light I band has a midline, a darker area called the
    Z disc or Z line
  290. A sarcomere is a region of myofibril between what?
    Two Z lines
  291. Myofilaments are ?
    Muscle equivalents of actin and myosin
  292. The A band has what kind of myofilaments?
    Think and thin
  293. The I band only has what kind of myofilaments?
    Thin
  294. Titin or �elastic filament� is between
    Z-line and M-line.
  295. What is the function of titin?
    May keep 3-d arrangement or may act in elastic recoil after being stretched
  296. What is the name of the thin myofilament?
    Actin
  297. What kinds of acin is there?
    • Globular and filamentous
    • Two strands of globular subunits twisted together into a helix. Each subunit has a myosin binding site.
  298. Tropomyosin � troponin complex is what? Describe shape.
    A rod-shaped protein; two chains in a helix loosely attached to the Filamentis actin
  299. What does tropomyosin help block?
    Myosin site on actin
  300. What is troponin?
    Globular polypeptide complex with three subunits
  301. What are the three subunits of troponin?
    • Troponin T
    • Troponin I
    • Troponin C
  302. What does troponin T do?
    Bind to tropomyosin at regular intervals (TnT)
  303. What does troponin I do?
    Inhibitory subunit; blocks binding site on actin (TnI)
  304. What does troponin C do?
    Binds calcium (TnC)
  305. What is the name of the think myofilament?
    Myosin
  306. Describe myosin.
    • Rod-like tail of two polypeptide chains twister together into a helix
    • Globular heads protrude from tails
  307. Each myosin head has?
    And ATP binding site and an Actin binding site.
  308. Describe what is within a myofilament.
    Within a thick myofilament, myosin molecules are arranged in parallel but staggered with tails in the central part of the myofilament and heads projecting outward at each end.
  309. What is the sarcoplasmic reticulum?
    • Modified smooth ER
    • Network of membranous tubules that surround myofilaments
  310. What does the sarcoplasmic reticulum consist of?
    Terminal cisternae and sarcotubules
  311. What is the job of the sarcoplasmic reticulum?
    To regulate the concentration of calcium within the sarcoplasm. It stores calcium when the muscle is relaxed and releases calcium in the initial steps of muscle contraction
  312. Transverse Tubule (T tubule) is what?
    • An invagination of the sarcolemma
    • Can propogate an action poteniital in the cell
    • Associated with the sarcoplasmic reticulum and forms a triad
  313. What is a triad?
    Terminal cisterna + T tubule + terminal cisterna
  314. The summary of t tubules and sarcoplaamic reticulum Arrangment. Each sarcomere is associated with:
    • � 2 t tubules (one at each AI band junction)
    • � 4 terminal cisternae (2 around each t tubule)
    • � 2 triads
  315. What is an action potential?
    Wave of negativity that propagates itself along the outside surface of an excitable membrane (muscle or nerve)
  316. What does depolarized mean?
    Outside goes from �+� to �-�
  317. What does repolarized mean?
    Outside goes back to �+� from �-�
  318. Neuromuscular junction and motor unit. The muscle needs to be stimulated to contract the stimulus comes from the
    Motor neurons
  319. What is a motor unit?
    • Motor neuron + all muscle cells that it innervates
    • All muscle cells w/in a motor unit will all contract & relax together
  320. Generation of a muscle contraction involves?
    • � Interaction of actin and myosin (cross-bridge formation)
    • � Energy source
  321. When relaxed what does tropomyosin-troponin do?
    It partially covers the myosin-biniding site on the actin.
  322. When relaxed describe ATP concentrations
    They are high and bound to the ATP-binding site on the myosin
  323. When relaxed explain calcium ion concentrations
    They are low in the sarcoplasm since they are being stored in the sarcoplasmic reticulum
  324. When the action potential reaches the synaptic bulb what happens?
    • Acetylcholine (A Ch) is released into the synaptic cleft
    • And it binds to a receptor on the sarcolemma
  325. What is the result of the the acetlcholine binding to a receptor on the sarcolemma?
    • It alters the permiablity of the sarcolemma
    • Depolarizes the sarcolemma
  326. the action potential is propagated over the surface of the muscle fiber by the sarcolemma and into the muscle fiber by way of the
    transverse tubule
  327. Depolarization of the T tubule leads to what?
    • Calcium ions released from the terminal cisternae of the sarcoplasmic reticulum
    • Which increases the calcium ion concentration in the sarcoplasm
    • Once the calcium ion conc in the sarcoplasm is increased what happens next?
    • Calcium ions and the myofilaments will now interact.
  328. Calcium binds to the troponin C on the thin myofilaments this causes?
    The tropomyosin-troponin complex to move and thus expose the myosin-binding sit on the actin
  329. Simultaneous with the calcium/myofilament interaction, the myosin is being �energized�. When the action potential stimulated the muscle, a high energy form of
    • Myosin(M*) is produced.
    • M-ATP --?M* + ADP +Pi
  330. When the myosin head is �energized�, it moves in an arc parallel to the long axis of the myofilament.
    • Cross bridge formation; actin and myosin bind together
    • A+M* ?A-M*
  331. Energy stores in the �energized� myosin head is no discharged
    • Powerstroke begins after the P is released, movement of the myosin head pulls the thin filament toward center of the sarcomere; ADP is released.
    • A-M* ? A-M + powerstroke
  332. Once the powerstroke is complete:
    • � New ATP binds to the myosins ATP binding site
    • o A-M + ATP ?A + M-ATP (cross bridge detachment)
    • � �Cocking� of the myosin head
    • o M-ATP ?M* + ADP + Pi(ADP and Pi remain attached)
    • � Cycle now repeats itself farther down the myofibril
    • o Sliding filament theory of muscle contraction
  333. During contraction the I Band?
    Decreases
  334. During contration the A band?
    Stay constant
  335. During contraction the H Zone?
    Decreases
  336. During contraction the area of overlap?
    Increases
  337. During contraction the M line?
    Decreases
  338. During contraction the Z line ?
    Constant but abuts thick myofilaments
  339. During contraction the sarcomere?
    Decreases
  340. During contraction the muscle cell length ?
    Decreases
  341. During contraction the whole muscle?
    Contracts
  342. Events leading to relaxation?
    • o Acetylcholine is destroyed by acetylcholineeastrease
    • o No more nerve impulses to the scarolemma
    • o Calcium ions are actively transoorted back into the sarcoplasmic reticulum
    • o Restores the blocing action of the tropomyosin-troponin complex
    • o ADP is resnthesized into ATP
    • o ATP binds to the myosin head
    • o Sarcomeres are returned to resting length
  343. As the muscle relaxes the I band?
    Increases
  344. As the muscle relaxes the A band?
    Is constant
  345. As the muscle relaxes the H zone?
    Increases
  346. As the muscle relaxes the area of overlap ?
    Decreases
  347. As the muscle relaxes the M line?
    Increases
  348. As the muscle relaxes the Z line?
    Is constant but no longer is next to the thick myofilaments
  349. As the muscle relaxes the sarcomere?
    Increases
  350. As the muscle relaxes the cell length?
    Increases
  351. As the muscle relaxes the whole muscle?
    Relaxes
  352. Energy for contraction is?
    Stored ATP = immediate, direct energy source
  353. Pathway to get more ATP?
    Direct phosphorlation of ADP by creatine phosphate (CP)
  354. Creatine phosphate is a high energy molecule that is how mch more abundant then ATP in the stored muscle cell?
    • 2-3 times
    • Creatine phosphate + ADP (creatine kinase)-?creatine + ATP (no oxygen used)
    • Quickly generates ATP
    • Muscle contraction continues for about 10 more seconds
  355. Another pathway to get more atp is anaerobic pathway involving glycolysis and lactic acid formation. Where does this happen?
    • In the cytoplasm, no oxygen is used.
    • Glucose in the blood goes to glycolysis which goes to ATP
    • Glycogen --?glucose which goes to glycolysis which goes to pyruvic acid --?lactic acid
    • Allows muscle to contact an additional 1-2 mins
    • Good for intermediate length athletic activites that may need extra power
  356. Anerobic pathway is about ____as fast as CP pathway and ___ times faster then aerobic pathway
    • Half
    • 2-3
  357. Aerobic pathway (oxidative metabolism)
    • Oxygen is required and it happens in the mitochondria
    • Cellular foodstuffs (glucose, fatty acids, amino acids) + oxygen ?aerobic respiration ?lots of ATP+CO2 + water
    • Adds hours of contraction
    • Good for prolonged athletic events
  358. All-or-none principle of Muscle Contraction
    Once a threshold stimulus is applied, individual muscle fibers of motor units will contract to their fullest extenet or will not contract at all
  359. Threshold stimulus ?
    Weakest stimulus that can initiate a contraction
  360. Sub threshold stimulus is?
    Lesser intensity stimulus that alone cannot initate a contraction
  361. A muscle as a whole structure may have �graded� contactions. There are many motor units in a muscle. If some motor units within that muscle are relaxed while others in that same muscle are contraction, then the muscle exhibits a ?
    �graded� contraction
  362. What is tension?
    Force exerted on an object by the muscle
  363. What is load?
    Force exerted on a muscle by an object
  364. Contraction is what?
    An active process of generating a force within a muscle
  365. How is a force generated?
    By the sliding of the myofilaments
  366. How is force exerted?
    Parallel to the muscle fiber cell
  367. Tension Vs. Load; To move an object?
    Tension > load
  368. Single twitch contraction � A twitch is?
    A mechanical respoins of muscle fibers to a single action potential (threshold)
  369. Experimental = In Vitro
    Not in life = In Vivo
  370. Single twitch contraction is recorded as a myogram. At time= 0, give a single threshold stimulus. What happens?
    • Latent period = calcium is released
    • Contraction period = repeated cross bridges and power strokes
    • Relaxation period = calcium is back into the sarcoplasmic reticulum
    • Refractory period = lost irritability
  371. Graded muscle response, variation in the degree of muscle contraction = graded contaction
    • Change frequency of stimulation
    • Change strength of stimulation
  372. What happens if the frequency of stimulation increases?
    Muscle contracts stronger (increase amount of tension/force)
  373. Summation: adding together of individual muscle twitches to increase the intensity of the muscle contraction
  374. Second stimulus given when the muscle is in a partially contracted state, what is going on?
    • � Calcium is once again released into the sarcoplasm
    • � Cross bridges can form;
    • � Second tension �adds� onto the first
  375. Incomplete tetanus (unfused tetanus). Describe.
    • � Threshold stimulus
    • � Constant strength
    • � Rate is rapid
    • � Partially relaxation �sustained but quivering� contraction on gross level
  376. Complete tetanus (fused tetanus). Describe.
    • � Threshold stiumuls
    • � Constant strength
    • � Rate is vary rapid
    • � No relaxation
    • � �smooth sustained contraction�
    • � Plateau of maximum tension
  377. Tetanus =
    Smooth, sustained contraction produced by a series of vary rapid threshold stimuli; muscle�s maximal response to high frequency stimulation
  378. Stimulus frequency for incomplete tetanus is less than that of
    complete tetanus
  379. Summation and tetanus occur because of:
    The nature of the contractile process. The physical nature of muscles and its connective tissue structures.
  380. With prolonged stimulation and continued strong contractions the muscle will fatigue. What is fatigue?
    Fatigue = inability to continue contracting
  381. What happens if strength of stimulation increases?
    Recruitment (multiple motor units)
  382. Threshold stimulus is the stimulus strength that produces the first observable muscle contraction.
    Skeletal muscles contain many motor units and typically not all of the motor units are contracting or relaxing at the same time. Once a threshold stimulus is applied individual muscle fibers in a motor unit will contract to their fullest extent or not at all.
  383. Skeletal muscles contain different types of muscle fibers (slow twitch red fibers, and fast twitch white) all muscles fibers within a motor unit are of
    the same type
  384. The number of activated motor units varies with stimulus strength (voltage). As the voltage of the stimulus increases, more and more motor units are activated until
    a maximal stimulus is reached and a maximal contraction results
  385. A weak threshold stimulus activates neurons with the
    lowest threshold (more excitable neurons)
  386. If increased stimulus to motor neurons, then more motor neurons with ___________ fire.
    higher thresholds
  387. A greater force of contraction occurs because more motor units are
    contracting within that muscle
  388. Low threshold motor neurons =
    • fatigue-resistant, slow twitch fibers (slow twitch red fibers)=
    • minimal force contraction
  389. Medium threshold motor neurons =
    • fatigue resistant, oxidative fast twitch fibers (fast twitch red fibers)
    • =�medium� strength contraction
  390. �high� threshold motor neuron =
    • glycolytic fast-twitch fibers;
    • fatigue quickly (fast twitch white fibers)=
    • sustained, maximal contraction
  391. As the stimulus intensity increases, larger motor units are recruited =
    �size principle�
  392. Asynchronous recruitment helps avoid
    fatigue
  393. Treppe:
    • � Staircase phenomena of muscle contraction
    • � Gradual increase in amount of contraction by a muscle caused by repeated threshold stimuli of the same strength
    • � Muscle has been at rest for some time prior to the initial threshold stimulus and threshold stimulus are given after complete relaxation
    • � Related to increased availability of calcium with addition contractions
    • � �warm ups�
  394. Muscle tone =
    residual degree of contractility
  395. Muscle tone
    • � Muscles maintain a certain level of tautness
    • � Muscle tone = residual degree of contractility
    • � Constant, slightly contracts state
    • � Due to a sustained partial contraction of some muscle parts
    • � Alternatively activate some motor units while others are at rest
    • � Tightens muscle w/o causing movement
    • � Spinal reflexes & strengthens muscles *muscle spasm
    • � Essential for maintain posture; keeps muscles firm and ready for action
  396. Type of skeletal muscle fibers:
    Two things to consider: myoglobin content & contraction velocities
  397. Myoglobin �
    • � reddish pigment
    • � Similar to hemoglobin
    • � Combines with oxygen and stores oxygen
  398. Red muscle fibers (myoglobin content, capillary supply, and mitochondria)
    • � Myoglobin content = high
    • � Capillary supply = very rich
    • � Mitochondria = abundant
  399. White muscle fibers (myoglobin content, capillary supply, and mitochondria & other)
    • � Myoglobin content = lower
    • � Capillary supply = not as rich
    • � Mitochondria = fewer
    • � Other features = larger diameter; more extensive sarcoplasmic reticulum
  400. Speed of contraction is related to?
    related to ability to split ATP
  401. Slow twitch fibers speed of contraction
    � slowly splits ATP therefore slower contraction speed
  402. Fast twitch fibers speed of contraction
    � quickly splits ATP therefore faster contraction speed
  403. Slow twitch red fibers - Color:
    Red
  404. Slow twitch red fibers - Myoglobin content:
    High ammt
  405. Slow twitch red fibers - Fiber diameter:
    Small
  406. Slow twitch red fibers - Mitochondria:
    many
  407. Slow twitch red fibers - Capillary supply:
    many (rich)
  408. Slow twitch red fibers - Glycogen stores:
    low
  409. Slow twitch red fibers - Speed of contraction:
    slow
  410. Slow twitch red fibers - Fatigue resistance:
    high
  411. Slow twitch red fibers - Location where fibers are abundant:
    Erector spinae group; pectoral muscles of migratory birds
  412. Slow twitch red fibers - Activities best suited for:
    maintain posture and enduace activites; capable of continuous, vigorous activity
  413. Fast twitch red fibers - Color:
    Red/pink
  414. Fast twitch red fibers - Myoglobin content:
    intermediate
  415. Fast twitch red fibers - Fiber diameter:
    intermediate
  416. Fast twitch red fibers - Mitochondria:
    intermediate
  417. Fast twitch red fibers - Capillary supply:
    intermediate
  418. Fast twitch red fibers - Glycogen stores:
    intermediate
  419. Fast twitch red fibers - Speed of contraction:
    Fast
  420. Fast twitch red fibers - Fatigue resistance:
    intermediate
  421. Fast twitch red fibers - Location where fibers are abundant:
    leg muscles
  422. Fast twitch red fibers - Activities best suited for:
    sprinting and walking
  423. Fast twitch white fibers �
    fast glycolytic fibers � anaerobic � glycolysis
  424. Fast twitch white fibers � Color: white/pale
  425. Fast twitch white fibers � Myoglobin content:
    low
  426. Fast twitch white fibers � Fiber diameter:
    large
  427. Fast twitch white fibers � Mitochondria:
    fewer
  428. Fast twitch white fibers � Capillary supply:
    fewer
  429. Fast twitch white fibers � Glycogen stores:
    high
  430. Fast twitch white fibers � Speed of contraction:
    fast
  431. Fast twitch white fibers � Fatigue resistance:
    low
  432. Fast twitch white fibers � Location where fibers are abundant:
    arm muscles, extraoculaar eye muscles; pectoral muscles of chicken and turkey
  433. Fast twitch white fibers � Activities best suited for:
    short bouts of very fast contractions
  434. Most muscles have a mixture of muscle fibbers and this gives them a range of
    contraction velocity and resistance to fatigue
  435. All fibers in a single motor unit are of the
    same type
  436. Smooth muscle fiber characteristics - shape and nucleus location
    Spindle-shaped cells with a centrally placed nucleus
  437. Smooth muscle fiber characteristics. Are there striations and what does the sarcoplasm have?
    • Not striated but the sarcoplasm does have thick and thick myofilamens that are arranged somewhat parallel to the long axis of the cell but not as orderly as in a skeletal muscle.
    • Smooth muscle fiber characteristics - is there sarcomeres?
    • No sarcomeres
  438. Smooth muscle fiber characteristics - describe actin, and what it does from the smooth muscles.
    • Greater actin overlap with myosin
    • � Permits a greater degree of contraction in smooth muscles
    • � Sliding filament theory
    • What other filaments are present for Smooth muscle fiber characteristics. Describe what they are and where they attach.
    • Intermediate filaments are also present
    • a) Cytoskeleton elements
    • b) Attach to dense bodies
    • i) Structures that are similar to z-lines
  439. Location of smooth muscles, and describe arrangement.
    • 1) Walls of hallow organs � single layer or several layers
    • 2) Arrector pili muscles � bundles
    • 3) Walls of BV � layers
    • 4) Iris of the eye � small groups
  440. Contraction physiology of smooth muscles
    • 1) Similar but slightly different then skeletal muscles
    • 2) Role of calcium ions
    • a) Regulates the contractile activity
    • b) Excite contractions by activating the ATPase activity (myosin head)
    • i) No effective troponin complex
    • ii) Acts directly on myosin
    • iii) ATPase ==?ATP breakdown + energy ==?contraction
  441. Sources of calcium ions of smooth muscles � Dual
    • 1) Some released from the poorly developed sarcoplasmic reticulum
    • 2) Some enter the cell from the extracellular fluid
  442. No T tubules � describe� smooth muscles
    • 1) Cisternae of the sarcoplasmic reticulum directly abut the sarcolemma
    • 2) Membrane action potential is thought to cause the release of calcium ions from the cisternae
  443. ATP Breakdown of smooth muscles
    • 1) Much slower then in skeletal muscle
    • a) Slows the overall speed of contraction � primarily anaerobic
  444. Excitability of smooth muscles
    • 1) Many smooth muscles cells undergo a continuous, low-level contractile activity without external stimuli which is called?
    • a) Intrinsic rhythmicity
    • b) Due to spontaneous activity in the cells
    • c) Result of ion changes inside and outside the cell
    • 2) Other causes of excitation
    • a) Neurotransmitters fro the autonomic nervous system
    • i) Epinephrine and norephrine � gut
    • b) Hormones - oxytocin ?uetrus
    • c) Rapid stretching � gut
    • d) Local env changes � pH, oxygen, ions�
  445. Two types of smooth muscle tissue arrangement
    • 1) Single unit smooth muscle
    • a) Stimulation in one cell spreads in waves to the other cells
    • b) Synchronous activity
    • i) Entire muscle responds as a single unit
    • ii) Contract in sequence as impulses spread from cell to cell
    • (1) Example:
    • (a) Uterine smooth muscle; intestinal tract smooth muscle; small diameter blood vessels
    • 2) Multiple unit smooth muscle
    • a) Individual smooth muscle cells are innervates
    • b) If stimulate a multiunit fiber; only that fiber contracts � no spread of inpulses
    • i) Examples:
    • (1) Large airways of the lungs; larger arteries; arrector pili; edge of iris
  446. Cardiac Muscle
    • 1) Principle constituent of the heart wall � myocardium
    • 2) Fibers - �cells�
    • a) Striated
    • i) Sarcomeres are present
    • b) Single central nucleus
    • c) More sarcoplasm with more and larger mitochondria
    • d) Larger T tubules at z lines
    • e) Sarcoplasmic reticulum is less developed that in skeletal muscles
    • f) Diads � not triads
    • g) Fibers are branched to form a functional syncytium
    • i) Mass of tissue that functions as a unit
    • h) Individual cells are separated from each other by irregular thickenings of the sarcolemma called Intercalated Discs - I.D.
    • i) Strengthens muscle tissue
    • ii) Aids in impulse conduction
  447. 3) Contractions
    • a) Moderate in speed and are rhythmical
    • b) Can occur intrinsically
  448. 4)Physiological differences between cardiac and skeletal muscles
    • a)Cardiac muscles require a constant oxygen supply - aerobic
    • b)Autorhythmicity
    • c)Calcium ions from the sarcoplasmic reticulum and the extracellular fluid - dual source
    • i)Contractions are prolonged
    • d)Long refractory period
    • i)Can relax between beats and therefore avoids tetanus and death

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