Finals Study

Question 1

what is the structure breakdown of skeletal muscle

Answer 1

muscle(with epimysium) -> fascicles -> fibres -> myofibrils (actin and myosin)

Question 2

what are the 3 major functions of skeletal muscle

Answer 2

stores protein (metabolism)
movement and force generation (electrical -> mechanical)
thermogenesis

Question 3

what are the 4 properties of skeletal muscle

Answer 3

excitable/irritable
contractile
extensible
elasticity

Question 4

what are the 8 factors that affect torque

Answer 4

1. activation history
2. cross-bridge function and energetics
3. size
4. type
5. elasticity/passive stiffness
6. neural activation/innervation
7. mechanics/attachments
8. antagonist balance

Question 5

what are the 2 component types of skeletal muscles

Answer 5

contractile components, and protein components

Question 6

what are the contractile components of muscle

Answer 6

actin and myosin

Question 7

what are the protein components of muscle

Answer 7

collagen and elastin -> make epimysium (muscle) perimysium (fascicles) and endomysium (fibres)

Question 8

what are the 6 roles of proteins

Answer 8

support contractile components
transmit force
resist stretch
mechanotransducers
protein metabolism
gene transcription

Question 9

what is included in the hill model (1938)

Answer 9

sarcomere, passive and elastic elements (elastic includes in series and parallel, both of with are contractile)

Question 10

is high elasticity good or bad? why?

Answer 10

good because high elasticity = more purposeful/controlled movement, low elasticity = jerky movements

Question 11

what is NMJ

Answer 11

chemical amplification of AP to depolarize

Question 12

what is ACh

Answer 12

secreted and binds to receptors on muscle -> depolarizes at membrane -> broken down by ACH esterase for Na channels to receive info

Question 13

what is E-C coupling

Answer 13

excitation-contraction -> depolarization to muscle to make force (aka electrical to mechanical transduction)

Question 14

what are the 2 types of force output determinants

Answer 14

intrinsic and extrinsic

Question 15

what are the 5 intrinsic force output determinants

Answer 15

size, shape, pennation/architecture, adaptability, and type/composition

Question 16

what are the extrinsic force output determinants

Answer 16

anything outside of individual muscle (aka neurons, fatigue/history, antagonists, etc.)

Question 17

in series vs parallel

Answer 17

in series = direct, increased ROM, and faster
parallel = lower ROM, but increased force

Question 18

what in the benefit of increased pennation

Answer 18

stronger force total (less per fibre) because more fibres acting

Question 19

what are the components of the motoneuron

Answer 19

soma, synapse, spinal cord, axon, axon hillock, dendrites

Question 20

what is the soma

Answer 20

the cell body

Question 21

what is the synapse

Answer 21

the electrical/chemical junction

Question 22

what is the spinal cord

Answer 22

regionalization aka UMN to LMN

Question 23

what is the axon

Answer 23

LMN (to muscle)

Question 24

what is the axon hillock

Answer 24

control center, chooses whether or not to send AP

Question 25

what are dendrites

Answer 25

to muscles (afferent)

Question 26

what are the 8 steps of AP firing

Answer 26

1. negative potential 2. excitation threshold reached 3. Na -> cell 4. Na in and K out (depolarization) 5. K out and increased membrane potential 6. K out and Mp normal (repolarization) 7. K and N channels close 8. K diffuses away (hyperpolarization)

Question 27

what is absolute vs relative refractory

Answer 27

absolute = cannot send AP relative = harder to send AP

Question 28

what is the order of conductance

Answer 28

K < Na < MP

Question 29

what is synaptic pots

Answer 29

input that does not reach the threshold

Question 30

what is rate coding

Answer 30

pattern and frequency of impulses

Question 31

what is the point of myelination

Answer 31

myelin increases conductance and speed, AP is re-energized at nodes