Brainscape's Knowledge GenomeTM

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


See full index

Physiology > Physiology Quiz 2 (1/2) > Flashcards

Physiology Quiz 2 (1/2) Flashcards

0
Q

Types of synapses

A

Electrical

Chemical

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

Synapse

A

Site at which an impulse is transmitted from one cell to another

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

Ephaptic communication

A

Two excitable cells communicating by direct passage of electrical current between them (aka electrical synapses)

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

Chemical synapses

A

A spike at the presynaptic membrane causes a release of neurotransmitter which attaches to receptors on the post synaptic membrane and causes depolarization

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

Characteristics of chemical synapses

A

Synaptic delay of .5-1 msec
Transmission is unidirectional
Pharmacological agents can interfere.

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

Characteristics of electrical synapses

A

No synaptic delay
Transmission is bidirectional
Pharmacological interference will not occur

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

Neuromuscular junction

A

Chemical synapse between a motor nerve and muscle cell(s)

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

Benzodiazepines*

A

Eg. Valium
Anti-anxiety for Pre-surgery
Blocks synaptic transmission*
Overuse can lead to too much transmission along nerve*

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

What happens when the spike arrives at the alpha motor nerve ending?

A
  1. Sudden large increase in calcium conductance at the presynaptic ending
    - calcium diffuses inward
    - attaches to enzymes, activating them
  2. Activated enzymes cause the vesicles containing neurotransmitter to release into cleft
    - Ach is neurotransmitter in neuromuscular junctions
  3. Ach diffuses across cleft
  4. Ach attaches to cholinergic receptor on post synaptic membrane
  5. Causes end plate potential (EPP)
  6. Potentials will sum and when threshold is reached, the cell fires an action potential
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Synaptic delay due to…

A

Time it takes for chemicals to get across synapse

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

Neurotransmitter at neuromuscular junction

A

Acetylcholine (Ach)

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

Two types of cholinergic receptors

A

Nicotinic

Muscarinic

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

Nicotinic receptors

A

Found on muscle, attach to nicotine or Ach

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Muscarinic receptors

A

Found on organ tissue (ie. cardiac tissue)

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

Atropine

A

Used to block poisons

Used in surgical settings to interfere with fluid production in lungs

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

Nicotinic cholinergic type receptors

A

Cholinergic receptors on muscle

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

Characteristics of nicotinic cholinergic receptors

A

Can attach to Ach

Can attach to nicotine

17
Q

End plate potentials (EPP)

A

Depolarizations of the postsynaptic membrane surface that are conduced electronically.

  • large numbers of EPPs will occur when the nerve fires a spike
  • Hesse must sum to cause a spike in the muscle membrane
18
Q

What happens every time an alpha motor nerve cell fires?

A

An excess of Ach is released

19
Q

Is it important to terminate the action of Ach at the neuromuscular junction?

A

Yes- for normal activity, muscles need to contract and relax

Eg. Lungs-muscles need to both contact and relax in order for you to breathe

20
Q

How termination of Ach is achieved

A

Broken down by acetylcholinesterase or by less specific cholinesterases

21
Q

Where is Ach-ase located?

A

On surface of postsynaptic membrane

22
Q

Where are cholinesterases located?

A

In extra cellular fluid in synaptic cleft

23
Q

What happens to Ach when it is attached to a receptor and the EPP is initiated?

A

It detaches

24
Q

Three possibilities for Ach molecule after it detaches from postsynaptic membrane

A
  1. Attaches to another receptor
  2. Attaches to acetylcholinesterase on the membrane and is destroyed
  3. Attaches to a cholinesterase in the synaptic cleft and is destroyed
25
Q

Is an Ach molecule more likely to attach to another receptor or to an esterase as it detaches?

A

More likely to attach to another receptor (1500 receptors/square micron) than an esterase (2600 esterases/square micron) but as it attaches and detaches, it will eventually run into an esterase

26
Q

What is Ach broken down into?

A

Acetyl CoA + choline

27
Q

What I acetylcholinesterase CoA used for?

A

Metabolism

28
Q

What is choline used for?

A

Actively transported back into nerve terminal and utilized again to manufacture Ach

29
Q

When Ach is manufactured in the cell body, how does it travel to the nerve terminal?

A

Antegrade axoplasmic transport by microtubules

30
Q

Succinylcholine

A

Attaches to nicotinic cholinergic receptors and initially activates then blocks (does not detach from site)
Used for: Relaxing muscles during surgery or when using a breathing machine (ventilator). It is also used to induce anesthesia or when a tube must be inserted in the windpipe.

31
Q

Tubocurarine

A

This attaches to nicotinic cholinergic receptors and blocks them. (No muscle rigidity, just relaxes)
Used for: a diagnosis agent for myasthenia gravis, and also to facilitate the intubation after induction of anesthesia in surgical procedure

32
Q

Alpha-neurotoxins

A

Block nicotinic cholinergic

preventing synaptic acetylcholine (ACh) from opening the ion channel.

33
Q

Loss of inner action of motor end plate

A

Can happen in trauma where nerve is cut
Can also happen when the nerve has undergone mechanical or toxic insult sufficient to stop the motor nerve from functioning

34
Q

What happens when the motor nerve input to the motor end plate is lost?

A

Skeletal muscle develops high sensitivity to Ach

  • thought to be due to a spread of receptors beyond the motor end plate
  • cause unknown
35
Q

Fasciculations

A

Low level uncoordinated contractions “quivering” of skeletal muscle

36
Q

mEPPs

A

(Miniature end plate potentials) small depolarizations that occur at the end plates without any activation of the alpha motor neuron

  • thought due to spontaneous release of Ach
  • some evidence that they are the tonic influence that nerves exert upon muscle to maintain it in a healthy state.
  • another idea-they are releasing a chemical compound (probably a combo of both)
37
Q

Botulism

A

Caused by ingesting food contaminated with spores of clostridium botulinum which attacks and destroys cholinergic nerve terminals creating acute denervation of motor end plates of muscle.

  • respiration stops
  • used in Botox injections
38
Q

Myasthenia gravis

A

Autoimmune process which destroys nicotinic cholinergic receptors

  • most common in females
  • facial muscles fatigue when eating is usually first complaint
  • long process, patient eventually dies
39
Q

Treatment for myasthenia gravis

A

Give anti-cholinesterase drugs

-increases concentration of Ach for more activation of receptors

40
Q

Osteophytes

A

Inappropriate growth of bone to stabilize joints

41
Q

How does compression affect axoplasmic transport?

A

Slows it down

Physiology (17 decks)

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