MSK/Neuro Phys

Question 1

What is the H, I

Answer 1

H- only myosin

I- only actin

Question 2

Which bands shorten during contraction and which stay the same size

Answer 2

H, I, Z bands shorten during contraction

A band stays the same size

Question 3

what are the 3 types of troponin

Answer 3

Troponin C- binds to calcium ions

Troponin T- Binds to tropomysoin

Troponin I - binds to actin and inhibits interaction bw actin and myosinn

Question 4

What are the steps of sliding filament theory

Answer 4

-action pot reaches t tubules and release calcium from the cistern or the sarcoplasmic reticulum

-calcium binds to troponin C causing shape change and shifting tropomyosin off actin

-myosin head pivots and pulls actin closer using 1 ATP

Question 5

Smooth muscle contraction steps

Answer 5

• action potential causes influx of Ca into the sarcoplasm
  Ca binds to calmodulin
  ca-calmodulin bins to and activates myosin light chain kinase

myosin phosphorylated by myosin light chain kinase
Myosin P binds to actin and causes the mm to contract

Question 6

What is the steps of the flexor withdrawal reflex

Answer 6

painful stim travels on axons of A delta and Class C dorsal root fibres

snaps with interneurons and then synapses on alpha motor neuron on ventral horn which inervates flexor mm to withal painful stim

(somatosomatic reflex)

Question 7

Steps of the crossed extensor reflex

Answer 7

fibres enter and synapse to multiple interneurons
while flexor response is being done on side of stim

Interneurons facilitate contraction of extensors on the opposite limb providing support

Question 8

stretch reflex inhibitory mechanisms

Answer 8

afferent neurons attach to renshaw cells in Lamina IX which sends inhibitory signals to antagonismt mm to relax

-also modulated by inhibitory signals from brain

Question 9

myelin is produced by what in the PNS and the CNS

Answer 9

PNS- Schwann cells

CNS- oligodendrocytes

Question 10

at a resting state what ion is more inside the cell

Answer 10

K+

Question 11

proportion of an action potential steps

Answer 11

stim triggers Na channels to open allowing Na to enter and the RMP becomes post

Once reaches peak Na channels close and K channels open (absolute refractory period)

Question 12

What are the only areas that depolarize and why is it important

Answer 12

Nodes of Ranvier which are devoid of myelin and thus depolarization jumps from node to node (50x faster saltatory conduction)

Question 13

what are the 2 types of synaptic connection s

Answer 13

Electrical/gap junction- cytoplasmic connections which allow direct conduction of electrical currents (bi directional)

Chemical type- NT diffuse across and is unidirectional

Question 14

What do Merkles cells do

Answer 14

Epidermis- crude touch and pressure

Question 15

Pancian corpuscles

Answer 15

deep subcutaneous
-vibration

Question 16

Meissners corpuscles

Answer 16

dermal papillae- two point discrimination (fine touch)

Question 17

Ruffini ending

Answer 17

deep subcutaneous tissue- jt pos sensee

Question 18

Naked nerve endings

Answer 18

found in epidermis and dermis- pain and temp

Question 19

What are the non excitatory neurotransmitters

Answer 19

Glycine and GABA

Question 20

what are the two major types of receptors in the ANS

Answer 20

Cholingergic
Adrenergic (norepinephrine)

Question 21

Types of cholinergic receptors and where are they found

Answer 21

all cholinergic receptors are nicotinic EXCEPT:

Parasympathetic postganglionic which are muscarinic

Question 22

What are the type of adrenergic receptors (5)

Answer 22

Alpha 1- smooth mm in blood vessels, gut etc (constriction)

Alpha 2- Found in islets of langerhan (decrease insulin sec)

Beta 1- found in cardiac mm (increase force + rate)

Beta 2- smooth mm bronchi, skeletal mm (dilation

beta 3- brown fat (increase lipolysis)