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expanded portion at each end of a long bone that articulates (forms a joint) with another bone.
On the outer surface of the articulating portion of the epiphysis is coated with a layer of hyaline cartilage.
The shaft of the bone, between the epiphyses.
- A tough, vascular covering of dense connective tissue. Completely encloses the bone, except for the articular cartilage on the bone's ends.
- Also helps form and repair bone tissue.
- tightly packed tissues.
- Has a continuous extracelluar matrix with no spaces.
- consists of numerous branching bony plates called trabeculae.
- Irregular spaces.
spongy bones of numerous branching bony plates.
- a hollow chamber in the diaphysis of a long bone.
- Is continuous with the spaces of the spongy bone.
A thin layer of cells, that line the medullary cavity.
soft connective tissue that fills the medullary cavity.
small, bony chambers which form circles around central canals.
osteocytes communicate with nearby cells by means of cellular processes passing through canaliculi
- the osteocytes and layers of extracellular matrix concentricall cluster around a central canal form a cylinder-shaped unit.
- Many of theses units cemented togeter form the substance of compact bone.
What does the central canal contain?
blood vessels and nerve fibers, surrounded by loose connective tissue.
What does the the vessels in the central canal do?
- Nourishes bone cells.
- communicate with the surface of the bone and the medullary cavity.
- Extend longitudinally through bone tissue.
connect the central canals.
How does spongy bone get nutrients?
the cells lie within the trabeculae and get nutrients from substances diffuseing into canaliculi that lead to the surface of these thin, bony plates.
Bones form by replacing exsisitn connective tissue in what 2 ways?
- Intramembranous bones originate between sheetlike layers of connective tissues
- Endochondral bones begin as masses of cartilage that are later replaced by bone tissue.
The broad, flat bones of the skull.
when extracellular matrix completely surrounds osteoblasts
the formation of bone
- Most of the bones of the skeleton.
- Form from masses of hyaline cartilage shaped like future bony structures.
Where does changes begin in the endochondral bone in a long bone?
In the center of the diaphysis.
How do endochondral bones form?
- Cartilage slowly breaks down and disappears.
- A periosteum forms from connective tissue that encircles the developing diaphysis.
- Blood vessels and osteoblasts from the periosteum invade the disintegrating cartilage, and spongy bone forms in its place.
- bone tissue develops from the primary ossification center toward the ends.
- osteoblast from the periosteum deposit a thin layer of compact bone around the primary ossification center.
- Then a secondary ossification center appear in the epiphysis.
a band of cartilage between the two ossification centers.
What does the epiphyseal plate do?
- Includes layers of young cells that are undergoing mitosis and producing new cells.
- As these cells enlarge and exstracellular matrix forms around them, the cartilaginous plate thickens, lengthening the bone.
Break down bone.
How long can a long bone lengthen?
- A long bone can lengthen while the cartilaginous cells of the epiphyseal plates are active.
- Once the ossification centers of the diaphysis and epiphyses meet and the epiphyseal plates ossify, lengthing is no longer possible in that end of the bone.
After being formed do bones need osteoclasts and osteoblasts?
Yes, 3-5% of bone calcium is exchanged each year.
What is necessary for proper absorption of calcium in the small intestines?
What is the function of bones?
- Bones shape, support, and protect body structures.
- Aid in body movements, house tissues that produce blood cells, and store inorganic salts.
when limbs or other body parts move, bones and muscles interact as simple mechanical devices.
What are the four basic components of a lever?
- A rigid bar or rod.
- a fulcrum or pivot on which the bar turns
- an object moved against resistance
- a force that supplies enery for the movement of the bar.
The process of blood cell formation.
soft netlike mass of connective tissue within the medullary cavitites of long bones, in the irregular spaces of spongy bone, and in the larger cental canals of compact bone tissue.
What kind of marrow is their?
Red and yellow
What is the function of red marrow?
Red marrow functions in the formation of red blood cells (erythrocytes), white blood cells (leukocytes), and blood platelets.
What does yellow marrow do?
yellow marrow stores fat.
What do bones store?
- The extracellular matrix of bone tissue is rich in calcium salts, mostly in the form of calcium phosphate.
What happens if the blood is low of calcium?
- Receptors: Cells in the parathyroid gland sense the decrease in blood calcium.
- Control center: Parathyroid glands release parathyroid hormone.
- Effectors: Ostoeclasts break down bone to release calcium.
- Response: Blood calcium level is returned to normal.
What happens if blood calcium levels are too high?
- Stimulus: Blood calcium levels increase.
- Receptors: cells in the thyroid gland sense the increase in blood calcium.
- Control center: Thyroid gland releases calcitonin.
- Effectors: Osteoblasts deposit calcium in bones.
- Response: Blood calcium level is returned toward normal.
Why is it important to maintain sufficient blood calcium levels?
Sufficient blood calcim leves are important in muscle cantraction, nerve impulse conduction, blood clotting
Besides storing calcium what othe materials can be in bones?
- Smaller amounts of magnesium, sodium, potassium, and carbonate ions.
- Sometimes harmful metallic elements such as lead, radium, or strontium accumulate in bones from accidentally ingesting.
What is the axial skeleton?
The axial skeleton consists of the bony and cartilaginous parts that support and protect the organs of the head, neck and trunk.
What parts are in the axial skeleton?
- Hyoid bone
- Vertebral column
- Thoracic cage
What is the skull composed of?
The cranium and the facial bones.
Where is the hyoid bone located?
In the neck between the lower jaw and the larynx.
What does the hyoid bone do?
It supports the tongue and is an attachment for certain muscles that help move the tongue during swallowing.
What does the vertebral column consist of?
- Many vertebrae separated by cartilaginous intervertebral discs.
- Near the distal end several vertebrae fuse to form the sacrum, which is part of the pelvis.
- At the very end is the coccyx, the tailbone composed of several fused vertebrae.
What makes up the thoracic cage?
- 12 pairs of ribs
- sternum (breastbone)
What do the ribs articulate with?
The ribs articulate posteriorly with thoracic vertebrae.
Where do most ribs attach to anteriorly?
What is the appendicular skeleton?
consists of the bones of the upper and lower limbs and the bones that anchor the limbs to the axial skeleton.
What bones are in the appendicular skeleton?
- Pextoral girdle
- Upper limbs
- Pelvic girdle
- Lower limbs
What forms the pectoral girdle?
- Scapula (shoulder blade)
- clavicle (collar bone)
What does the pectoral girdle do?
Connects the bones of the upper limbs to the axial skeleton and aids in upper limb movements.
What does the upper limbs consist of?
- Humerus (arm bone)
- two forearm bones
- Carpals (wrist bones)
- metacarpals (palm)
- phalanges (fingers)
What articulates at the elbow joint?
The humerus, radius and ulna.
How many bones does the carpals consist of?
How many bones are in the metacarpals?
How many bones are in the phalanges?
How many bones are in the human body?
What makes up the pelvic girdle?
- Two hip bones
How is the pelvic girdle formed?
hip bones attached to each other anteriorly and to the sacrum posteriorly.
What does the pelvic girdle connect to?
The lower limbs to the axial skeleton and the sacrum and coccyx, form the pelvis.
What does the lower limbs consist of?
- Femur (thigh bone)
- 2 leg bones
- Tarsals (ankle bones)
- metatarsals (instep)
- phalanges (toes)
What articulate at the knee joint?
the femur and tibia.
How many bones are in the tarsals (ankle bones)?
How many bones are in metatarsals (instep)?
How many bones are in the phalanges?
What is the vertebral column composed of?
vertebrae that are separated by masses of fibrocartilage called intervertebral discs and are connected to one another by ligaments.
What is the function of the vertebral column?
- Support the head and trunk of the body.
- Protect the spinal cord which passes through a vertebral canal formed by openings in the vertebrae.
What are the two short stalks projecting posteriorly from each vertebral body called?
The two plates that arise from the pedicles are called what?
What is the spinous process?
two plates called laminae arise from the pedicles and fuse in the back to become the spinous process.
What is a complete vertebral arch?
The pedicles, laminae, and spinous process.
What does the vertebral arch surround?
What does the spinal cord pass through?
What projects laterally from the vertebral arch?
What projects posteriorly from the vertebral arch?
What are attached to the spinous process and the trasverse process?
Ligaments and muscles
What are projecting upward and downward from each vertebral arch?
The superior and inferior articular process.
The superior and inferior articular processes do what?
bear cartilage coverd facets by which each vertebra is joined to the one above and one below it.
What are intervertebral foramina?
openings on the lower surface of the vertebral pedicles for passageways for spinal nerves.
How many bones make up the cervical vertebrae?
What is the first vertebra?
What is the second cervical vertebra?
What does the atlas articulate with?
Two kidney shaped facets that articulate with the occipital condyles on the superior surfance and the axis. On the distal side of the atlas which dens project from the axis the atlas lies.
What process projects upward from the axis and what movement does it perform?
The odontoid press or dens and it lets the atlas pivot around the dens turning the head side to side.
How many vetebrae are in the thoracic spine?
In the thoracic vertebrae what do each vertebrae articulate with?
The spinous process articulates with a rib.
How many bones are in the lumbar vertebrae?
How many fused vertebrae form the sacrum?
The spinous processes of the sacrum form a ridge called what?
How many vertebrae compose the coccyx?
What are the first 7 ribs called?
true ribs, they join the sternum directly by their costal costal cartilages.
What are 8th through the 12th ribs called?
False ribs because the cartilages do not reach the sternum directly. The last two ribs are called floating ribs.
What are the three parts of the sternum?
- Upper manubrium
- Middle body
- lower xiphoid process
What does the manubrium articulate with?
The clavicles by facets on its superior border.
What does the pectoral girdle support?
It supports the upper limbs and is an attachment for several muscles that move them.
Where is the clavicles located?
collarbone, located at the base of the neck, they run horizontally between the naubrium and the scapulae. (attach arm)
Where is the scapulae located?.
on either side of the upper back.
What does the humerus articulate with?
the glenoid cavity in the scapula and radius and ulna.