Lecture 13- Muscle Physiology

Question 1

components of the somatic nervous system

Answer 1

includes all sensory neurons, and all of the motor neurons

Question 2

Somatic nervous system function

Answer 2

controls skeletal muscle, voluntary movement

Question 3

three types of muscles

Answer 3

• skeletal: voluntary control, has striations
• cardiac: involuntary, striations
• smooth: involuntary no striations
• all muscles are excitable cells that produce action potentials ( but first must have a AP–> produce a contraction

Question 4

sarcomere

Answer 4

fundamental units made up of myofibrals
( binding protein) ( contractile unit of the muscle cell)

is made up off
thin fliaments (actin)
thick fliaments (myosin)
- actin and myosin cause the muscle to contract

Question 5

thin fliaments

Answer 5

made up of actin 
contains
- actin 
- tropomysoin
- tropoin

Question 6

thick filaments

Answer 6

made up off myosin
contains two parts
- heads: binds actin, uses ATP
- tails: binds to other myosin molecules

Question 7

muscle fiber

Answer 7

contains protein filaments that cause muscle contraction

Question 8

actin

Answer 8

myosin binding site

Question 9

tropomyosin

Answer 9

blocks and covers all myosin sites and binding at rest

Question 10

troponin

Answer 10

Calcium protein that binds Ca2+ and moves tropomyosin

Question 11

types of muscle structure includes

Answer 11

• muscle fibers
• sacromere ( made up by thin, thick filaments
• SR and t-tubules (both play a role in muscle contraction

Question 12

SR

Answer 12

endoplastmic rectriculum in a muscle cell

functions include

• stores calcium
• help move proteins

Question 13

t- tubules

Answer 13

structures that transmits action potentials from the sacromere into a cells interior

Question 14

motor neuron

Answer 14

regulate skeletal muscle contractions ( forming a synapse)
- two ways it does this by
reflex: muscle movement in response to a stimulus
voluntary movement: muscle movement with conscious intent

Question 15

motor neuron neurotransmitter

Answer 15

is acetylcholrine (ACh) 
receptor on muscle cells: nicotinic ACh receptor

Question 16

motor unit

Answer 16

motor neurons plus all the muscle cell it innervates

Question 17

nueromusclular junction (NMJ)

Answer 17

synapse between a motor neuron and skeletal muscle

Question 18

motor endplate

Answer 18

part of the muscle cell that forms a synapse

with the motor neuron

Question 19

endplate potential (EEP)

Answer 19

depolarizes of a muscle cell at the NMJ

- voltage gated Na+ and K+ channels respond to the EPP and open–> produces an Action potential

Question 20

muscle anatomy

Answer 20

muscles: made up of many muscle cells, called muscle fibers

muscle cell: contractile organelles called myofibrals

myofibrils: made up or contractile proteins ( myosin and actin)

Question 21

DHP Ryanodine

Answer 21

are receptors on the T-tubules

• link T-tubules and SR
• are voltage sensitive( open when VM becomes more positive)

Question 22

what is the sliding filament hypothesis (role of Ca, ATP)

Answer 22

mechanism of myosin heads “sliding” actin toward the center of the sarcomere

• role of Ca: excitation signal - required to free myosin binding spots ( no Ca= no binding)
• role of ATP: required for powerstoke cross bridge released ( no ATP= no release. no muscle contraction)