SG 6: Chap 7 Neurons Flashcards

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1
Q

What is a nerve?

A

is a bundle of parallel axons and dendrites that transmit nervous impulses between nerve cells and various parts of the body.

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2
Q

what is a sensory neuron?

A

it conducts information towards the brain and spinal cord.

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3
Q

what is a motor neuron?

A

it carries information away from the brain and spinal cord to an effector (muscle or gland)

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4
Q

what is an interneuron?

A

these are located between the motor and sensory neurons. only found within the brain and spinal cord and account for more than 99% of the body neurons. JOB: integrate and interpret the sensory singnals

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4
Q

What are functions of glial cells ?

A

Also known as neuroglial cells, some provide structural support for the neurons of the brain and spinal cord, others provide a steady supply of chemicals(nerve growth factor) that stimulates nerve growth, others form insulating sheaths around the axons called myelin sheath (Schwann cells) these cells can communicate w/one another & w/neurons

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6
Q

How do neurons differ from glial cells In Terms of cell division?

A

Glial cells retain the ability to undergo cell division in adulthood whereas most neurons can’t.

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7
Q

what is the myelin sheath?

A

composed of the plasma membrane in multiple layers of the glial (schwann) cell, it increases the of conduction of a nerve impulse & helps its repair. it covers most of the axons outside the brain and spinal cord and some w/in.

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8
Q

what is a Schwann Cell?

A

forms neurons myelin sheaths. insulates individual axons and prevents messages from short circuiting between neurons.

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9
Q

what are the nodes of Ranvier?

A

the gaps between the Schwann cells, where the axon is exposed. A function is that they allows nutrients and waste to enter and exit the neuron, and facilitate the rapid conduction of the nerve impulses.

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10
Q

what is the gray matter?

A

is the region of the CNS that contain neuron cell bodies, dendrites and axon terminals and unmyelinated axons.

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11
Q

what is the white matter?

A

regions of the CNS but mainly PNS that are myelinated nerve fibers(axons). these are important for communication over long distances.

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12
Q

Saltatory conduction function?

A

is a transmission where with the assistance of myelin sheath in place, a nerve impulse “jumps” successfully from one rode of ranvier to the next. These axons are 100% faster than a single conduction.

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13
Q

what is Multiple Sclerosis?

A

it is a disease in which the myelin sheaths in the brain and spinal cord are progressively destroyed. Damaged regions of the myelin sheath become hardened scars which interfere w/the transmission of nerve impulses. depending of the region of the nervous system, results can be paralysis, loss of sensation, including loss of vision.

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14
Q

what is ALS ?

A

short of Amyotrophic Lateral Sclerosis. ALS is a disease in where only motor neurons throughout the brain and spinal cord die and stop sending messages to the skeletal muscles. w/out stimulation from the motor neurons, muscles gradually weaken & person loses control of body movement.
leads to respiratory failure(death) since muscles that control breathing eventually die

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15
Q

What is a Nerve Impulse?

A

also known as action potential, its an electrochemical signal caused by Na+ ions and K+ ions crossing the neurons membrane to enter and leave the cell.

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16
Q

What are the diff concentrations inside and outside of the cell of Na+ and K+ ions during diff stages?

A

Resting potential: + in the outside & – in the inside

action potential: – in the outside & + + in the inside

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17
Q

what structures in the plasma membrane participate in the transport of these ions?

A

gated ions channels and Sodium-Potassium pumps.

18
Q

what are Ion channels when regarding a Nerve Impulse?

A

are pores in the neuron membrane that dont need cellular energy to pass through.
Na+ channels & K+ channels

19
Q

what are Pumps when regarding a nerve impulse?

A

Na+-K+ pump are special proteins that actively(using cellular energy in form of ATP to move ions across their concentration gradient) transports Na and K ions across the membrane.
pumps out 3 Na+ ions and intakes 2 K+ ions
the pump restores the original levels of charges after action potential took place back to resting potential.

20
Q

What is “resting potential?” and what is the ions concentration?

A

is a charge difference across the membrane which results from unequal distribution of ions. no conduction impulse. inside is neg, and outside is positive. Na+ greater in the outside, and K+ greater inside the neuron.

21
Q

what is action potential? and what is the ion concentration?

A

or Nerve impulse. is when the neurons receive an ecitatory signal which results in a sudden reversal in the charge difference across the membrane followed by the restoration of the original charge diff. Neg in the outside and positive in the inside.

22
Q

what happens during depolarization? Depo= deposit

A

depo= deposit Na+ gated ion channels open and Na+ ions enters which results in the ++ charges increase inside the axon membrane.

23
Q

what happens during repolarization? repo=take

A

repo=take about 1/2 way through the action potential, K+ gated ion channels open and K+ ions flow out. as k flows back out, almost returning the charge differences to resting potential.

24
Q

what is refactory period?

A

occurs after action potential when neurons cannot be stimulated. Na+ ions channels are closed and cant be opened. inside more neg than outside

25
Q

what is a synapse?

A

is the region of close proximity between a neuron and another cell, separated by a synapse cleft.

26
Q

what is a synapse cleft?

A

the gap between the presynaptic cell and the postsynaptic cell.

27
Q

what is a synpatic knob?

A

an axons branch end. these branches end with a small bulklike swelling known as a knob

28
Q

what is a presynaptic cell?

A

a cell that is sending the message

29
Q

what is a post-synaptic cell?

A

the neuron receiving the message

30
Q

In a synaptic transmission, what happens after the nerve impulse reaches the axon ending(synaptic knobs) of the pre-synaptic neuron?

A

the gates of Na+ open, Na+ ions enter the knob resulting in the release of the neurotransmitters into the synaptic cleft from the synaptic vesicles. .

31
Q

what happens after the neurotransmitters are diffused across/into the synaptic cleft?

A

the neurotransmitter binds to its receptor on the membrane of a postsynaptic neuron and an ion channel is opened.

32
Q

In a synaptic transmission, what is the role of a receptor?

A

it is a specified protein that only recognizes a particular assigned neurotransmitter. when the neurotransmitter binds to a receptor it causes the opening of an ion channel.

33
Q

what happens to the neurotransmitters after they are released?

A

they are quickly removed, so their affect is temporary. 2 ways the neurotransmitter can be released, 1 way enzymes can deactivate them and 2nd, the neurotransmitter may be actively pumped back into the presynaptic knob.

34
Q

what is Acetylcholine & Norepinephrine?

A

they are neurotransmitters that act both in the cns and pns. although both have excitatory & inhibitary affects, whatever the effect of norepinephrine has on any particular organ, acetylcholine will have the opposite.

35
Q

Acetylcholines role in neuromuscular junction?

A

Acetylcholine is the neurotransmitter that is released at every neuromuscular junction where it triggers contractions of voluntary skeletal muscles

36
Q

what is myasthenia gravis?

A

an autoimmune disease in which the body defense mechanisms attack the acetylcholine receptors. ppl with myasthenia gravis have little muscle strength.

37
Q

what are some of the neurotransmitters?

A

Acetycholine: triggers voluntary skeletal contraction, Norepinephrine: regulates mood, pleasure system of the brain, and arousal, Serotonin: promotes a generalization feeling of well-being, Dopamine: helps regulate emotions

38
Q

what is alzheimers?

A

is a progressive disease and results in loss of memory particularly on recent events followed by severe personality changes. the hippocampus and cerebral cortex lose a large amount of neurons. acetyclocline decreases as much as 90% in these regions.

39
Q

what is Prozac?

A

Its an antidepressant that specifically affects serotonin functioning, increasing the level of serotoninin the synapse by reducing its rate of removal.

40
Q

what are the bases of depression and pakinson’s disease?

A

depression: insufficient levels of the neurotransmitters: dopamine, serotonin, and norepinephrine
Pakinsons disease: is a progressive disorder that results from the death of dopamine producing neurons.

41
Q

Be able to describe the structure of a neuron and the function of each one of its parts

A

(cell body, dendrite, axon)