Section 3: Muscle Physiology

Question 1

type of voluntary muscle

Answer 1

Skeletal

Question 2

types of involuntary muscles

Answer 2

smooth

cardiac

Question 3

Muscle composition

4 layers, starting with muscle

Answer 3

muscles made of fascicles, made of muscle cells (muscle fibres) made of myofibrils

Question 4

sarcomeres

Answer 4

repeating units of actin and myosin

Question 5

two types of actin

Answer 5

G actin

F actin

Question 6

A band

Answer 6

contains actin and mysoin

Question 7

I band

Answer 7

only actin

Question 8

H zone

Answer 8

only myosin

Question 9

M line

Answer 9

where myosin attaches to eachother

Question 10

z line

Answer 10

where actins attach to each other

Question 11

5 steps to sliding filament theory

Answer 11

1) rigor state
2) ATP binds to myosin head (releases actin)
3) ATP hydrolysis (myosin head swings)
4) Pi released, Power stroke
5) ADP released, rigor state resumes

Question 12

cause of rigor mortis

Answer 12

lack of ATP, myosin cannot unbind to actin

Question 13

Function of tropoyosin

Answer 13

binds around actin. blocks myosin binding site

Question 14

parts of troponin (3)

Answer 14

TnC - Binds Ca2+

TnT - Binds tropomyosin

TnI - binds actin to tropomyosin (inhibits binding, hence I)

Question 15

t-tubule system

Answer 15

allows action potential to move into interior of cell

Question 16

motor end plate receptor type

Answer 16

nicotinic

Question 17

active tension vs passive tension

Answer 17

active - caused by actin / myosin

passive - caused by stretching elastic components

Question 18

tetanus

Answer 18

no relaxation of the muscle. Produces maximal tension

Question 19

motor unit

Answer 19

all muscle fibres innervated by a single motor neuron

Question 20

things that increase force (2)

Answer 20

recruitment - more fibres
can also do asynchronous recruitment to avoid fatigue

Summation - ap frequency

Question 21

Types of contractions (2)

Answer 21

isotonic - creates a force and moves a load

isometric - does not move load

Question 22

types of isotonic contractions

Answer 22

concentric - normal

eccentric- muscle lengthens as tension develops (may be damaging)

Question 23

extrafusal fibres

Answer 23

major contractile fibres

Question 24

alpha motor neurons

Answer 24

innervate extrafusal fibres

Question 25

intrafusal fibres

Answer 25

form part of the sensory apparatus

Question 26

muscle spindles

Answer 26

detect when stretched

Question 27

gamma motor neurons

Answer 27

end of spindles to contract

Question 28

golgi tendon organs

Answer 28

located in tendons, detect force

Question 29

origin of inhibitory neuron

Answer 29

upper motor neuron (UMN)

Question 30

motor cortex

Answer 30

decides movements

Question 31

cerebellum

Answer 31

provides adjustment as movement proceeds

damage leads to jerky movements

Question 32

basal ganglia

Answer 32

coordinates slow, sustained contractions

Damage (Parkinson’s) causes resting tremor