Exam 1 Review

Question 1

What are the 10 steps to muscle contraction?

Answer 1

1. AP starts in the brain
2. AP arrives at axon terminal, releases ACh
3. ACh crosses synapse, binds to ACh receptors on plasmalemma
4. AP travels down plasmalemma and T-tubules
5. Triggers Ca2+ release from SR
6. Ca2+ binds to troponin on thin actin filament
7. Troponin-Ca2+ complex moves tropomyosin revealing connecting point for myosin head
8. Myosin head connects to actin and pulls actin toward sarcomere center (the power stroke)
9. After power stroke ends, myosin detahces from active site, head rotates back to original position, then attaches to another active site farther down the actin chain
10. Process continues until Z-disk reaches myosin filaments or AP stops and CA2+ gets pumped back into the SR

Question 2

What are the two different parts of the nervous system?

Answer 2

Central and peripheral

Question 3

What are the parts of the motor system?

Answer 3

• somatic (voluntary, control of skeletal muscles)
• autonomic (involuntary, to viscera)

Question 4

What are the parts of the peripheral nervous system?

Answer 4

sensory (incoming)
motor (outoging)

Question 5

What are the two parts of the autonomic system?

Answer 5

• sympathetic (fight or flight)
• parasympathetic (rest and digest)

Question 6

As a power athlete, which autonomic system will be activated? What does this system do?

Answer 6

• sympathetic system
• releases adrenaline which will: raise HR, BP, RR; increase blood flow to extremities; dilate pupils

Question 7

What does the parasympathetic system do?

Answer 7

• opposite of sympathetic
• decreases HR, BP, RR; increases blood flow to organs

Question 8

What order are muscle fibers recruited?

Answer 8

• smallest to largest
• type 1, type 2a, type 2b/2x

Question 9

What part of your brain does conscious muscle movement occur in?

Answer 9

motor cortex of the frontal lobe

Question 10

What is the smallest contractile unit of a muscle? What is its common boundary?

Answer 10

• sarcomere
• common boundary is the z-disk

Question 11

What is the difference between a motor unit and a sarcomere?

Answer 11

a motor unit is a single alpha motor neurons and all of the fibers it innervates

Question 12

How many fibers are there in a type 1 motor neuron? Type 2?

Answer 12

• type 1 has a small motor neuron, with less then 300 fibers
• type 2 has a large motor neurons, with more than 300 fibers

Question 13

What is the motor neuron conduction velocity for type 1 motor neuron, type 2?

Answer 13

• type 1 = 100 ms (slow twitch)
• type 2 = 50 ms (fast twitch)

Question 14

What is the cellular voltage change of a gradient potential?

Answer 14

resting membrane potential is -70mv, the cell then depolarizes to threshold (-55mv), then to 30mv; the cell then hyperpolarizes all the way back down to -90mv, then it regulates itself and depolarizes back to -70mv

Question 15

Muscle spindles

Answer 15

• reflex response
• sensitive to muscle length and rate of change
• directly stimulate the muscle, cause 100% contraction/full contraction

Question 16

Golgi tendon organs

Answer 16

• reflex response
• are sensitive to tension in the tendon
• inhibits APs to the muscles, causes 0% contraction/complete relaxation

Question 17

What are the 3 major protein strands of a muscle?

Answer 17

• myosin: powerhouse, made up of myosin and globular heads
• actin: made up of actin, tropomyosin, and troponin
• titin: prevents overstretching, made up of titin

Question 18

What is the Length tension relationship?

Answer 18

• optimal sarcomere length equals optimal overlap, if too short or too stretched, little or no force develops
• the more the sarcomere overlaps, the stronger the muscle is, maximum strength is at 50% contraction

Question 19

What is the force velocity relationship?

Answer 19

• concentric: maximal force development decreases at high speeds - in order to create velocity, you must give up force
  
  • the more myosin cross bridges you have, the less velocity you have, and vice versa
• eccentric: maximal force development increases at higher speeds

Question 20

What is the process that makes small molecules into larger ones?

Answer 20

anabolism

Question 21

What is the process that makes large molecules into smaller ones?

Answer 21

catabolism

Question 22

What do enzymes do?

Answer 22

• decrease the activation energy of a metabolic reaction
• makes the reaction happen quicker, therefore creating more yield