Muscle, Bone, Skin

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Muscle, Bone, Skin
2013-01-24 11:45:14

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  1. 1. What are the 3 types of muscle tissue?
    2. What are 4 possible functions of muscle contraction?
    3. What type of muscle is voluntary aka consciously controlled?
    4. How do muscles connect to bone? How do bones connect to bones?
    • 1. Skeletal, cardiac, and smooth.
    • 2. Body movement, stabilization of body position, movement of substances throughout body, and generating heat to maintain body temp
    • 3. skeletal
    • 4. Tendons connect muscles to bones; ligaments connect bones to bones.
  2. 1. Why does it require more force than mg for skeletal muscles to lift things?
    2. Are muscles synergistic?
    3. How can skeletal muscle help circulation? (2)
    4. How does skeletal muscle produce heat? What is an ex of this?
    • 1. To reduce bulk of body and increase range of movement (shorter arm=shorter lever).
    • 2.Yes
    • 3. May squeeze blood and lymph vessels aiding circulation.
    • 4. Contraction of skeletal muscle produces large amounts of heat (aka shivering, controlled by hypothalamus upon stimulation by receptors in skin/spinal cord)
  3. 1. What is the smallest functional unit of the skeletal muscle?
    2. What are the two strands of protein filaments that make up a sarcomere and what are they each made of?
    3. What do sarcomeres combine to make? What is each of these combined groups surrounded by?
    • 1. Sarcomere
    • 2. Thick filament (several myosin) and thin filament (actin)
    • 3. Myofibrils, by sarcoplasmic reticulum.
  4. 1. What is attached to actin? (2)
    2. What is the 5 stage cycle?
    1. Troponin and tropomyosin

    • 1. Tropomyosin covers active site of actin preventing myosin head from binding.
    • 2. In presence of Ca2+, active site is exposed, allowing myosin head to bind.
    • 3. Myosin head expels a phosphate and ADP, bends into low energy position taking actin with it (POWER STROKE - causes shortening of sarcomere and muscle contraction).
    • 4. ATP attaches to myosin head, releasing myosin from active site and myosin goes back to high energy position.
  5. 1. What does a muscle contraction begin with?
    2. What happens after that? (4)
    3. What happens at the end?
    • 1. Action potential - a neuron attaches to muscle cell forming a neuromuscular synapse.
    • 2. The action potential of neuron releases acetylcholine into synaptic cleft, activating ion channel in sarcolemma of muscle creating an action potential.
    • 3. The action potential moves deep into muscle cell via small tunnels in membrane called T-tubules
    • 4. Action potential spreads to sarcoplasmic reticulum, allowing release of Ca2+ ions.
    • 5. Ca2+ ions begin 5 stage cycle.

    At the end of each cycle, Ca2+ is ACTIVELY pumped back into sarcoplasmic reticulum.
  6. 1. What do T-tubules allow for?
    2. What happens to H zone and I band during relaxation? during maximum contraction?
    3. What generally happens during contraction?
    4. What never changes size?
    5. What to what does sarcomere span?
    • 1. Unified contraction of muscle by allowing action potential to spread through muscle cell more quickly.
    • 2. At relaxation, H zone and I band are at maximum width. During maximum contraction, H zone disappears and I band becomes very narrow.
    • 3. Actins are pulled toward the center of each myosin filament, causing sarcomere to shorten.
    • 4. A band.
    • 5. I band to Z band
  7. 1. Why does the H zone disappear in fully contracted muscle?
    2. Do muscles requiring intricate movements have small motor units or larger motor units? What about muscles requiring greater force?

    3. Why are muscles red?
    • 1. Because the ends of the actin myofilaments overlap.
    • 2. Intricate movements require smaller motor units.
    • 3. Bc of large amounts of myoglobin - stores O2 but has only one protein subunit.
  8. Describe the color, fatiguability, contraction speed of Type I, Type II A and Type II B muscle fibers.

    Which has the lowest myoglobin count? Highest? Which is most resitant to fatigue and most susceptible to fatigue?
    1. Type I: slow-twitch, lots of mitochondria, slow to fatigue, slow contraction velocity.

    Type IIA: fast twitch, contract rapidly, resistant to fatigue, but not as much as Type I.

    Type II B: Low myoglobin content (high glycogen content) contract rapidly and fatigue rapidly.
  9. 1. Do muscle cells undergo mitosis? Why or why not? How do muscle cells grow?
    2. During a muscle contraction, does the thin or thick filament contract?
    3. What would happen if calcium couldn't be released from SR?
    4. How do muscles cause movement at joints?
    • 1. Bc they are so specialized - stuck in G0. Hypertrophy.
    • 2. Neither! Instead, the proportion of actin and myosin overlap increases.
    • 3. It would prevent myosin from binding to actin.
    • 4. Decreasing in length thereby bringing muscle's origin and insertion closer together.
  10. 1. Which muscles are striated? What does that mean?
    2. How do skeletal muscle and cardiac muscle differ in terms of nuclei?
    3. Is cardiac muscle connected to bone?
    4. How are cardiomyocytes separated from their neighbors?
    • 1. Cardiac & Skeletal - it means they contain sarcomeres.
    • 2. Skeletal = multinucleated while cardiac muscle cells only have one nucleus.
    • 3. No - it forms a net that squeezes together like a fist to contract.
    • 4. By intercalcated discs
  11. 1. After depolarization, why do cardiomyocytes exhibit plateau?
    2. What is the result of the plateau?
    • 1. Plateau is created by slow voltage-gated calcium channels which allow calcium to enter and hold inside membrane creating a positive potential difference.
    • 2. Longer contraction
  12. 1. What is smooth muscle innervated by?
    2. How many nuclei does it have?
    3. Does smooth muscle have sarcomeres? Do they have thick and thin filaments?
    4. What other type of filament does smooth muscle have? What are these filaments connected to throughout the cell?
    5. What does smooth muscle contract and relax in response to? (7)
    • 1. Autonomic nervous system
    • 2. 1
    • 3. No, yes.
    • 4. Intermediate filaments attached to dense bodies
    • 5. Neural stimulus, hormones, CO2, O2, pH, temperature and ion concentrations.
  13. 1. What is the function of the gap junctions in the intercalcated discs of the cardiac muscle?
    2. During an action potential, a cardiac muscle cell remains depolarized much longer than a neuron. Why?
    3. Why does smooth muscle also need Ca2+ to contract?
    4. What do all muscles need to be excited?
    5. What type of muscle is found in vessels?
    • 1. To insure the action potential is spread to all fibers in muscle network.
    • 2. Prevent the initiation of another action potential during contraction of the heart.
    • 3. Bc it contains thick and thin filaments which require Ca2+ to work.
    • 4. Increased cytosolic calcium concentration
    • 5. Smooth muscle
  14. 1. What are the 6 functions of bone?
    2. What are the four types of cells found in bone tissue? - name the 3 important ones
    • 1. Support of soft tissue, protection of internal organs, body movement, blood cell production,mineral storage, and energy storage in the form of adipose cells in bone marrow.
    • 2. Osteoblasts, osteoclasts, and osteocytes
  15. 1. What is the function of osteoblasts? What do they differentiate into? Are they capable of mitosis?
    2. Are osteocytes capable of mitosis? What is their function?
    3. What do osteoclasts do? What do they develop from?
    • 1. Osteoblasts secrete collagen & organic compounds upon which the bone matrix is formed. They differentiate into osteocytes. No.
    • 2. No. They exchange nutrients and waste with the blood.
    • 3. Osteoclasts resorb minerals into bloodstream. They are formed from monocytes (WBC)
  16. 1. What type of bone contains red bone marrow? What type has yellow bone marrow?  Why are they these respective colors?
    2. What structure do osteocytes use to exchange nutrients?
    3. What vessels do Haversian canals have? What are they connected by?
    • 1. spongy bone contains red bone marrow bc that's where RBCs develop. Compact bone contains yellow bone marrow, contains adipose cells for energy storage.
    • 2. Canaliculi
    • 3. Blood & lymph vessels, volkmann's canals
  17. 1. What form of Ca2+ is most important in the blood?
    2. Where is most Ca2+ stored in the body?
    3. Which salts buffer plasma Ca2+ levels?
    4. What two ions do bones store?
    • 1. Free
    • 2. In bone matrix as hydroxyapatite
    • 3. Calcium phosphate
    • 4. Ca2+ and HPO42-
  18. 1. Nam examples of long bones.
    2. Name examples of short bones
    3. Name examples of flat bones; two functions?
    • 1. Long bones: legs, arms, fingers, toes
    • 2. Ankle and wrist bones
    • 3. Skull, sternum, ribs and shoulder blades - provide large areas for muscle attachment and organ protection.
  19. 1. Does cartilage have blood vessels or nerves?
    2. What is the most common type of cartilage and what are its two functions?
    3. Which joints allow movement?
    • 1. No.
    • 2. Hyaline - reducing friction and absorbs shock in joints.
    • 3. Synovial joints. Also contains macrophages to get rid of products of wear and tear.
  20. What are 7 important functions of the skin?

    What are 2 principal parts of the skin?
    Thermoregulation, protection, environmental sensory input, excretion, immunity, blood reservoir, vitamin D synthesis.

    Epidermis and dermis.
  21. 1. How does skin regulate body temperature? (3)
    2. How are water and salts excreted through skin? Is it dependent on sweating?
    3. What type of tissue is the epidermis? Does it have vasculature? What germ cell does it derive from?
    4. What type of tissue is the dermis? What germ cell does it come from? What 4 things does it have?
    • 1. Heat can be dissipated by endothermic evaporation of sweat or by radiation.
    • 2. Blood can be shunted away from capillaries of skin to reduce heat loss, keeping body warm.
    • 3. Hairs can be erected via sympathetic stimulation, trapping insulating area next to skin.

    • 2. Through diffusion. NOOO
    • 3. Epithelial - no, it's avascular. Ectoderm.
    • 4. Connective tissue derived from mesoderm cells. It has blood vessels, nerves, glands, and hair follicles.