Brainscape's Knowledge GenomeTM

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


See full index

Anatomy and Physiology > Nervous Tissue Lecture 4 > Flashcards

Nervous Tissue Lecture 4 Flashcards

1
Q

What are the factors that influence the speed of propagation?

A
  • Amount of myelination
  • Axon diameter
  • Temperature
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

How are nerve fibers classified based on propagation speed?

A

A fibers (Very fast)
B fibers (Moderately fast)
C fibers (Slowest)

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

What are the characteristics of A fibers?

A
  • Largest diameter axons and myelinated, therefore FASTEST
  • Speeds up to 130 m/sec.
  • Associated with touch, pressure, proprioception, some pain, and temperature sensations
  • Conduct APs to skeletal muscles
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Describe B fibers.

A
  • Moderate sized diameters and myelinated, therefore moderately fast
  • Speeds up to 15 m/sec.
  • Found in ANS & visceral organs
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What are the characteristics of C fibers?

A
  • Smallest diameters with no myelination, therefore SLOWEST
  • Slowest of the 3 fibers.
  • Found in reproductive, urinary, excretory, digestive neurons, nociceptors from skin and viscera
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What is the site of communication between two neurons or a neuron and an effector cell?

A

Synapse

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

What are the terms used to describe neurons before and after the synapse, and the connections between an axon and a dendrite/cell body?

A
  • Pre-synaptic neuron
  • Post-synaptic neuron/cell
  • Axo-dendritic (connection between an axon and a dendrite)
  • Axo-somatic (connection between an axon and a cell body)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What type of synapse contains gap junctions and what are its advantages?

A
  • Electrical synapses
  • Advantages: Faster communication, synchronization, allows a large number of neurons or muscle fibers to produce action potentials in unison
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What is the most abundant type of synapse and what are its advantages?

A

Chemical synapses
Advantages: Can modulate response, can be excitatory or inhibitory

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

What are the steps involved in chemical synapses?

A
  • Arrival of action potential at the pre-synaptic neuron’s synaptic end bulb
  • Membrane depolarization opens voltage-gated Ca2+ channels, allowing Ca2+ influx
  • Ca2+ stimulates exocytosis of synaptic vesicles containing neurotransmitters (NTs)
  • NTs diffuse across the synaptic cleft and bind to receptors on the post-synaptic membrane
  • Binding of neurotransmitters to receptors opens ligand-gated channels, allowing ion flow
  • Ion flow generates a graded potential (post-synaptic potential)
  • Signal ends when NT is broken down by an enzyme and recycled, diffuses out of the synaptic cleft, or taken back into pre-synaptic neuron.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What is the process involved in the integration of information in a single neuron?

A
  • Single neuron may receive information from thousands of synapses, both excitatory and inhibitory.
  • Axon hillock integrates all stimuli and determines the rate of action potential generation at the initial segment.
  • The sum of all excitatory and inhibitory effects at any given time determines the effect on the postsynaptic neuron.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What happens during synaptic fatigue and what are its consequences?

A
  • Neurotransmitters are usually reabsorbed and recycled.
  • After extended stimulation, the supply of neurotransmitter may not keep up with demand.
  • Synapse is unable to function until ACh (acetylcholine) is replenished.
  • Inability to function leads to synaptic fatigue.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What are the two types of neurotransmitter receptors?

A
  • Ionotropic receptors (Ligand-gated receptors)
  • Metabotropic receptors (G-protein coupled receptors)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What are the characteristics of ionotropic receptors?

A
  • Neurotransmitter receptor connected directly to an ion channel
  • Can be excitatory or inhibitory
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

How do metabotropic receptors function?

A
  • Uses a messenger protein (G Protein) to open certain ion channels
  • Usually inhibitory
  • Acetylcholine (ACh) can be excitatory at some synapses (ionotropic) and inhibitory at others (metabotropic)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What are the two major categories of neurotransmitters?

A
  • Small-Molecule Neurotransmitters
  • Peptide Neurotransmitters
17
Q

What are the functions of acetylcholine?

A
  • Excitatory neurotransmitter at NMJ
  • Excitatory between pre-ganglionic and post-ganglionic neurons of the autonomic nervous system (ANS)
  • Inhibitory neurotransmitter in cardiac muscle in response to parasympathetic NS
18
Q

What are examples of excitatory and inhibitory amino acid neurotransmitters?

A
  • Excitatory: Glutamate and aspartate
  • Inhibitory: Gamma-aminobutyric Acid (GABA) (CNS), Glycine (NMJ)
19
Q

What are examples of biogenic amine neurotransmitters?

A
  • Epinephrine and norepinephrine
  • Dopamine (DA)
  • Serotonin (5-HTP)
20
Q

What are the functions of nitric oxide as a neurotransmitter?

A
  • Potent vasodilator
  • Excitatory neurotransmitter in the brain
  • Important in generating and maintaining an erection
21
Q

What are characteristics of peptide neurotransmitters?

A
  • Found in CNS and PNS
  • Both excitatory and inhibitory
  • Usually bind to metabotropic receptors
  • Many are also hormones
22
Q

How can the effects of neurotransmitters be modified?

A
  • NT synthesis can be stimulated or inhibited
  • NT release can be enhanced or blocked
  • NT receptors can be activated or blocked
  • NT removal can be stimulated or inhibited
23
Q

What are neural circuits?

A

Functional groups of neurons that process specific types of information.

24
Q

What are the different types of neural circuits?

A
  • Simple
  • Diverging
  • Converging
  • Reverberating
  • Parallel after-discharge
25
Q

Describe a simple neural circuit.

A

The simplest type of neural circuit where a presynaptic neuron stimulates a single postsynaptic neuron, which then stimulates another, and so on (very rare).

26
Q

What is a diverging neural circuit?

A

A single neuron stimulates multiple neurons, leading to signal amplification.

27
Q

Explain a converging neural circuit.

A

Multiple neurons stimulate a single neuron, allowing for summative effects.

28
Q

What characterizes a reverberating neural circuit?

A

Similar to simple circuits, but branches from later neurons synapse with earlier ones, causing reverberation backwards. For example, coordinated movement, short-term memory, and breathing.

29
Q

Describe a parallel after-discharge neural circuit.

A

In this circuit, a single presynaptic neuron stimulates multiple neurons, which all synapse back to a common postsynaptic cell

30
Q

What is neuroplasticity?

A

Neuroplasticity refers to the capability of the nervous system to adapt and change based on experience. changes can include:

  • sprouting of new dendrites
  • synthesis of new proteins
  • alterations in synaptic contacts with other neurons.
31
Q

Define neuroregeneration.

A

Neuroregeneration is the capability of neurons to replicate or repair themselves. In the peripheral nervous system (PNS), mild to moderate damage to neurons often allows for the recovery of nerve function, facilitated by the protective sheath called the neurolemma. However, the central nervous system (CNS) lacks regenerative capabilities.

32
Q

What is neurogenesis?

A

Neurogenesis refers to the birth of new neurons from undifferentiated stem cells.

33
Q

What changes occur when there is damage to an axon?

A

When an axon is damaged, changes occur in both the cell body and the distal portion of the axon. Chromatolysis involves Nissl body degranulation in the neuron as part of repair, while Wallerian degeneration is the degeneration of the distal axon and its myelin sheath.

34
Q

How do Schwann cells respond to axonal injury?

A

Schwann cells multiply and form a regeneration tube at the injured site, guiding new axon growth from the proximal area. Axons usually grow at a rate of approximately 1.5 mm per day.

Anatomy and Physiology (21 decks)

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