Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Anaphy Lec > Unit 3 Part 3 > Flashcards

Unit 3 Part 3 Flashcards

1
Q

chemical components and reactions that
occur when a muscle is stimulated by a __

A

motor nerve

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

sliding of each myofibril within a muscle
fiber cause __

A

muscle fiber to shorten

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

the result when many muscle fibers shorten

A

contraction of the skeletal muscle.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Physiology of Contraction

A

– 1st – synaptic transmission at the
neuromuscular junction
– 2nd – excitation-contraction coupling
– 3rd – contraction-relaxation cycle

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Capable of self-generating electrical impulses
at their membranes

A

excitable

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Electrical potentials

A

exist across the membranes of essentially all cells of the body

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Concentration difference of ions across a selectively permeable membrane can produce a

A

membrane potential

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

The difference in potential ( voltage ) between
the inner side & outer side of the membrane
(nerve or muscle membranes)

A

What Is a Membrane Potential

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

more negative and more K+

A

Inside cell

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

more positive and more Na+

A

Outside cell

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

– Must exist for action potential to occur
– The value for Vm in inactive muscle cells is typically btwn –80 and
–90 millivolts.
– Cells that exhibit a Vm are said to be polarized.
– Vm can be changed by influx or efflux of charge.

A

Membrane Potentials

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

States of a Membrane Potential

A
  • (1) Resting Membrane Potential ( RMP)
  • (2) Graded Potential (Local Response)
  • (3) Action Potential
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

It ranges between -70 and -90 mV in different
excitable tissue cells

A

Resting Membrane Potential ( RMP)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

It ranges between -70 and -90 mV in different
excitable tissue cells

A

Resting Membrane Potential ( RMP)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Voltage difference is the result of

A

-positive charge is constantly leaking out of the cell
-Contribution of Na+-K+ pump
-protein anions

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

-MP in a stimulated cell that is producing a local , non-propagated potential;

-an electrical change which is measurable only in
the immediate vicinity of the cell but not far
from it.

A

Graded Potential (Local Response)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

MP in case of a nerve/muscle that is generating a propagated electrical potential after stimulation by effective stimulus

A

Action potential(AP)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

– Large changes in cell membrane potential (charge)
– Inside of the cell becomes more positive relative to the outside of the cell
– Function to transmit information over long distances
– Electrical signal that travels along the nerve axon and ends at the synaptic terminal
– All-or-none principle
– RESULTS IN: Releases neurotransmitter
(acetylcholine or ACh)

A

Action Potentials

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

level of depolarization needed to trigger an action potential. Action potential does not occur until this has been reached.

A

Threshold potential

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

-state membrane suddenly becomes permeable to Na+ ions;
-Allows tremendous numbers of (+) charged Na+ ions to flow to the interior of the axon; Potential rises rapidly in the (+) direction

A

Depolarization stage

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

Na channels begin to close; K channels open more than they normally do;
Rapid diffusion of K+ ions to the exterior re-establishes the normal negative resting membrane potential

A

Repolarization

22
Q

Membrane potential may briefly become over negative; due to opened voltage-gated K channels

A

Hyperpolarization

23
Q

-a motor neuron and all the muscle fibers it
supplies
-All the muscle cells controlled by one nerve cell

A

Motor unit

24
Q

-Interface of the motor neuron and muscle fiber
-Region where the motor neuron stimulates the muscle fiber
-where the neuron meets with the muscle fiber.

A

Neuromuscular junction (NMJ)

25
Q

Where communication occurs between a somatic
motor neuron and a muscle fiber

A

Synapse

26
Q

Gap that separates the axonal ends and muscle
fibers ; filled with interstitial fluid

A

Synaptic cleft (20-30 nm wide)

27
Q

The neuromuscular junction is formed by :

A

-End of motor neuron axon (axon terminal)/synaptic
end bulb/Pre-synaptic terminal
-The motor end plate of a muscle/Sub-synaptic or
Post-synaptic membrane

28
Q
  • Terminals have small membranous sacs (synaptic
    vesicles) that contain the neurotransmitter
    acetylcholine (ACh)
A

End of motor neuron axon (axon terminal)/synaptic
end bulb/Pre-synaptic terminal

29
Q
  • A specific part of the sarcolemma that contains ACh
    receptors
  • Chemically-gated Na+ channels
  • Acetylcholinesterase enzyme
A

The motor end plate of a muscle/Sub-synaptic or
Post-synaptic membrane

30
Q

-The synaptic end bulb is filled w/ vesicles that
contain the neurotransmitter
-The neurotransmitter for skeletal muscle is

A

acetylcholine

31
Q

The motor end plate is chock full of

A

acetylcholine receptors

32
Q

Chemical released by the initial cell communicating with the second cell

A

Neurotransmitter

33
Q

– travels across the synaptic cleft
– binds to membrane receptors on sarcolemma (motor end plate)
– Sarcolemma becomes permeable to sodium
– causes sodium–ion rush into sarcoplasm
– is quickly broken down by enzyme
(acetylcholinesterase or AChE)

A

Acetylcholine or ACh

34
Q

enzyme that breaks down acetylcholine

A

(acetylcholinesterase or AChE)

35
Q

-act as gated ion channels
-channels that are normally closed, but in response to a certain signal, they will open and allow specific ions to pass through them.
-When a channel is open, its specific ion(s) will
enter or exit depending on their
electrochemical gradient.

A

Integral Proteins

36
Q

Ion Channels Important in Muscle Contraction

A
  • Voltage-gated Ca2+ channel in Pre-synaptic
    terminal
  • Nicotinic Acetylcholine Receptor Channel
  • Chemically-gated Na+ channels in Sub-
    synaptic/Post synaptic Membrane
37
Q

-mediates neurotransmitter release
-At the pre-synaptic membrane of the neuron
- When an action potential spreads over these channels open and allow calcium ions to diffuse from the synaptic space to the interior of the nerve terminal.
- Causes synaptic vesicles to fuse with the neural
membrane and empty their acetylcholine into the synaptic space by the process of exocytosis.

A

Voltage-gated Calcium Channels

38
Q

-in muscle neuromuscular junction (postsynaptic membrane, or end plate)
- mediates electrical transmission from nerve to muscle

A

Nicotinic Acetylcholine Receptor Channel

39
Q

Events at the NMJ

A
  1. arrival of action potential at the synaptic terminal
  2. release ACh
  3. ACh binding at the motor end plate
  4. appearance of action potential in the sarcolemma
  5. return to initial state
40
Q

The ACh present in the synaptic cleft is broken
down by the enzyme ___ into _____

A

Acetylcholinesterase; Acetyl coA+ choline

41
Q

The ACh is again synthesized by the nerve cell
body and then send by ___ to the presynaptic terminal for packaging into secretory vesicles.

A

anterograde flow

42
Q

An autoimmune neuromuscular disorder in which the
Neuromuscular junction is blocked.

A

MYASTHENIA GRAVIS

43
Q

cause of myasthenia gravis

A

Auto-antibodies are formed against the
Ach receptors on the Motor End Plate.

These antibodies completely destroy the receptors.

44
Q

Some myasthenia gravis patients have
other auto-immune disorders as well such as

A

RA, poliomyelitis.

45
Q

-hallmark of Myasthenia gravis
-seen with prolonged use of the skeletal muscles.
-Muscles become progressively weaker during periods of activity and improve after periods of rest.

A

fatigue

46
Q

Fatigue is usually more pronounced in the ___ as tongue, ___ as eye movements, ___ as swallowing, ___ as talking

A

proximal muscles
occulomotor
phryngeal
laryngeal muscles

46
Q

Fatigue is usually more pronounced in the ___ as tongue, ___ as eye movements, ___ as swallowing, ___ as talking

A

proximal muscles
occulomotor
phryngeal
laryngeal muscles

47
Q

drooping of the eyelids

A

ptosis

48
Q

double vision

A

diplopia

49
Q

DIAGNOSIS MYASTHENIA GRAVIS

A
  • Presence of autoantibodies in the plasma
  • Nerve conduction study
  • Edrophonium test - Tensilon, a drug that blocks the
    degradation (breakdown) of acetylcholine
50
Q

TREATMENT MYASTHENIA GRAVIS

A
  • Anti-cholinesterase drugs.e.g: Neostigmine
  • Immunosuppressant drugs. E.g: glucocorticoids
  • Thymectomy: removal of thymus helps rebalances
    the immune system.

Anaphy Lec (13 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions