Physiology Quiz 3 (1/2)

Question 0

EPSP

Answer 0

Excitatory Pre/post synaptic Neuron

Question 1

IPSP

Answer 1

Inhibitory Pre/post synaptic neuron

Question 2

What do IPSPs do?

Answer 2

Hyperpolarizes the membrane of the synapse

• stops/slows action potential
• more action potentials/sec = more hyperpolarization

Question 3

What do EPSPs do?

Answer 3

Moves membrane closer to threshold without accommodation.

-speeds up synaptic transmission

Question 4

Dale’s Law

Answer 4

One nerve cell makes only one neurotransmitter and utilizes only one neurotransmitter

Question 5

Gamma-Aminobutyric Acid

Answer 5

AKA GABA

Common inhibitory neurotransmitter

Question 6

What determines excitatory vs inhibitory properties

Answer 6

Depends on the combination of neurotransmitter and receptor

-eg. Norepinephrine- inhibitory on certain receptors and excitatory on others

Question 7

How is nerve-nerve transmission different from nerve-muscle transmission?

Answer 7

• multitude of neurotransmitters used in nerve-nerve

- can have inhibition at synapse in nerve-nerve

Question 8

What does the brain perceive more action potentials as?

Answer 8

More pain

Question 9

What does the brain perceive less action potentials as?

Answer 9

Less pain

Question 10

What must IPSPs and EPSPs do in order to have influence on the nerve fiber or cell?

Answer 10

Their small electrical changes must sum

-they sum algebraically

Question 11

How do IPSPs and EPSPs travel?

Answer 11

Electrotonic conduction

Question 12

How would you define integration in a neuromuscular system or a neural system?

Answer 12

Process by which a decision is made for what to do (if anything) based upon all the input coming into the nerve cell
-all IPSPs and EPSPs sum and how this changes the nerve membrane will determine whether or not an action potential is fired

Question 13

General functions that muscles perform

Answer 13

Angular motion (flexion/extension)
Linear motion (abdominal contraction for trunk stabilization)
Pressure or volume changes (cardiac muscles)

Question 14

Sarcomere

Answer 14

Functional unit of a muscle

Question 15

Z-protein

Answer 15

Composes “z-line” and holds actin filaments in place

Question 16

Myofibrils

Answer 16

Components of a muscle cell

Question 17

I-band

Answer 17

Straddles 2 sarcomeres and includes the region of the sarcomeres where there are only actin filaments

Question 18

A-band

Answer 18

Region in the middle of the sarcomere

• encompasses entire length of the myosin filaments
• includes the region of overlap of actin and myosin filaments

Question 19

H-zone

Answer 19

Middle of the sarcomere

Only area where there are only myosin filaments

Question 20

M-line

Answer 20

Line of structural proteins (m-proteins) that hold myosin filaments in place

Question 21

“Thick” filaments of the sarcomere

Answer 21

Myosin

Question 22

“Thin” filaments of the sarcomere

Answer 22

Actin

Question 23

Crossbridges

Answer 23

Present on the myosin filaments

-attach to actin filaments during contraction

Question 24

G-actin

Answer 24

Globular proteins that make up actin filaments

Question 25

Tropomyosin

Answer 25

Blocks actin from myosin crossbridges when muscle is relaxed | Calcium sensitive

Question 26

Troponin

Answer 26

Determines the location of the tropomyosin on the actin filament

Question 27

What is the purpose of the hinges on the myosin crossbridges?

Answer 27

Allow the crossbridges to move and attach to the actin during muscle contraction, or to detach from actin during relaxation

Question 28

Sarcoplasmic reticulum

Answer 28

Surrounds the myofibrils Contains fluid almost identical to ECF Supplies calcium to ICF during muscle contraction

Question 29

What happens to calcium conductance as an action potential travels over a cell membrane?

Answer 29

Increases | -allowing movement of calcium into cell from outside

Question 30

Where else does calcium conductance increase when an action potential travels over muscle cell aside from membrane?

Answer 30

Sarcoplasmic reticulum | -allows flow from inside SR to interior of muscle cell

Question 31

What does calcium do once inside muscle cell?

Answer 31

Attaches to troponin -troponin moves tropomyosin off the actin and into the "groove" -allows myosin crossbridges to attach to actin Muscle contracts

Question 32

Wen is calcium pumped out of the cell?

Answer 32

When action potentials stop traveling across membrane | -muscle relaxes

Question 33

LMM

Answer 33

Light meromyosin | Horizontal part of actin chain that makes up crossbridges

Question 34

HMM

Answer 34

Heavy meromyosin (Makes up chain that angles outward to attach to actin) Has 2 subunits (S1 and S2) -S2 head is part that attaches to actin

Question 35

What happens in a cramp

Answer 35

Not due to activation of motor neuron | Ionic imbalance causes an action potential which opens up calcium channels and starts crossbridge cycle

Question 36

ADPs role in crossbridge cycle

Answer 36

(Phase 2) when ADP is attached to S2 head, it has very high affinity to actin -ADP releases after phase 2

Question 37

What happens to crossbridge cycle if ATP not present

Answer 37

S2 head will not release from actin (stuck at phase 3) Muscle stays contracted Rigor mortis

Question 38

What happens after S2 head attaches to actin?

Answer 38

S2 head shifts actin toward sarcomere | Muscle shortening

Question 39

Role of ATP during crossbridge cycle

Answer 39

Aids in resetting of S2 head by giving it low affinity for actin

Question 40

Are crossbridges synchronous?

Answer 40

No. They are asynchronous . There will be crossbridges in all phases at any given moment during contraction

Question 41

A+M

Answer 41

Actin and myosin are in close proximity to each other, but are not attached

Question 42

M.ADP.Pi

Answer 42

Myosin is attached to ATP and inorganic phosphate

Question 43

A+M.ADP.Pi

Answer 43

Muscle is relaxed

Question 44

What happens to ATP after it attaches to the S2 head?

Answer 44

It is broken down, producing ADP and inorganic phosphate

Question 45

What is the energy produced by ATP hydrolysis used for?

Answer 45

Re-cocking the S2 head for more cycling

Question 46

What is the source of muscle tone?

Answer 46

Low level of spontaneous activity of cross bridges

Question 47

Intracellular pool

Answer 47

Pool where calcium flows from the SR to ICF

Question 48

Extracellular pool

Answer 48

Pool where calcium flows from ECF to ICF