Brainscape's Knowledge GenomeTM

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


See full index

MCAT Biology Review > The Nervous System > Flashcards

The Nervous System Flashcards

You may prefer our related Brainscape-certified flashcards:
MCAT flashcards AP® Biology flashcards Biology 101 flashcards
1
Q

Soma

A

Cell body of neuron, location of nucleus and ribosomes

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

Dendrites

A

Appendages from soma that receive incoming messages from other cells

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

Axon hillock

A

Integrates incoming signals, transmits action potentials (transmission of electrical impulses down axon), sums up all signals (excitatory and/or inhibitory) and yields action potential if sum is excitatory

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

Myelin

A

Fatty membrane that insulates nerve fibers to prevent signal loss, crossing of signals, and speed of conduction in axon

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

What produces myelin?

A

Oligodendrocytes (central nervous system) and Schwann cells (peripheral nervous system)

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

Nodes of Ranvier

A

Small breaks in myelin sheath with exposed areas of axon membrane, used for rapid signal conduction

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

Nerve terminal or synaptic bouton (knob)

A

Flattened end of axon to maximize transmission of signal to next neuron and releases neurotransmitters

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

Demyelination

A

Destruction of myelin as a result of immune response, slowing down information transfer (one disorder is multiple sclerosis)

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

Synaptic cleft

A

Small space into which terminal portion of axon from presynaptic neuron release neurotransmitters to dendrites of adjacent (postsynaptic) neuron

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

Synapse

A

Consists of nerve terminal, synaptic cleft, and postsynaptic membrane

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

Nerve

A

Bundle of multiple neurons in peripheral nervous system, can be sensory, motor, or mixed

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

Ganglia

A

Cluster of cell bodies of neurons of same type in peripheral nervous system

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

Tract

A

Bundle of axons in central nervous system, can only carry one type of information

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

Nuclei

A

Bundle of cell bodies of neurons in same tract in central nervous system

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

Astrocytes

A

Form blood-brain barrier

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

Ependymal cells

A

Line ventricles of brain and produce cerebrospinal fluid, a shock absorber

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

Microglia

A

Phagocytic cells that break down waste products and pathogens in CNS

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

List of all glial cells

A

Astrocytes, ependymal cells, microglia, oligodendrocytes (CNS), Schwann cells (PNS)

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

Resting membrane potential

A

Net electric potential difference that exists across cell membrane (-70 mV in neurons), generated and maintained by potassium and sodium ions, closer to potassium’s equilibrium potential as cell is slightly more permeable to potassium

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

Potassium leak channels

A

Allow for slow leak of potassium out of cell in this favorable direction due to potassium concentration inside cell being 140 mM compared to 4 mM outside cell, leaving behind small amount of negative charge and making outside slightly positively charged

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

Equilibrium potential of potassium

A

Around -90 mV, negative sign is due to positive potassium ion leaving the cell

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

Sodium leak channels

A

Facilitates diffusion of sodium down its gradient into cell as there are 12 mM of sodium inside cell and 145 mM outside of cell

23
Q

Equilibrium potential of sodium

A

Around 60 mV, positive sign due to positive sodium ion moving into cell

24
Q

Na+/K+ ATPase

A

Continually pumps sodium out of cell and potassium into cell to maintain respective gradients and membrane potential (process in body that uses the most ATP)

25
Q

Depolarization

A

Raising the membrane potential from its resting potential and readying neuron for action potential, caused by excitatory input

26
Q

Hyperpolarization

A

Lowering membrane potential from its resting potential and making neuron less likely to fire action potential, caused by inhibitory input

27
Q

Threshold

A

The value in the range of -55 to -40 mV at which an action potential will be triggered if axon hillock receives enough excitatory input

28
Q

Summation

A

Additive effect of multiple signals

29
Q

Temporal summation

A

Multiple signals are integrated during relatively short period of time

30
Q

Spatial summation

A

Additive effects based on number and location of incoming signals

31
Q

Once cell is brought to threshold

A

Voltage-gated sodium channels open, promote migrate of sodium into cell down electrochemical gradient, making membrane potential more positive and depolarizing cell

32
Q

Inactivation and deinactivation

A

When membrane potential approaches +35 mV, sodium channels are inactive and membrane potential has to be brought back near resting potential to be closed but active again

33
Q

Three states of sodium channels

A

Closed (before cell reaches threshold after inactivation is reversed), open (from threshold to +35 mV), inactive (from +35 mV to resting potential)

34
Q

Repolarization

A

Restoration of membrane potential by potassium ions leaving neuron as result of depolarization, leading to hyperpolarization of neuron

35
Q

Absolute and relative refractory period

A

Absolute: no stimulation can cause another action potential
Relative: greater than normal stimulation required to cause action potential as membrane is hypepolarized

36
Q

Impulse propagation

A

Action potential travels down the axon to initiate neurotransmitter release, sodium rushing into one segment of axon causes depolarization in surrounding regions of axon to bring them to threshold, opening their sodium channels
Only unidirectional, segment with fired action potential becomes momentarily refractory

37
Q

How does speed of moving action potential depend?

A

Greater speed: lesser length, greater cross-sectional area, myelin (in mammals)

38
Q

Saltatory conduction

A

Signal hops from node of Ranvier to node as membrane is only permeable to ion movement at the nodes due to myelin

39
Q

Neurotransmitter release

A

When action potential reaches nerve terminal, voltage-gated calcium channels, allowing calcium influx, triggering fusion of membrane-bound vesicles with cell membrane at synapse to exocytosize neurotransmitter

40
Q

Methods to remove neurotransmitters from synaptic cleft

A

Broken down by enzymatic reactions (such acetylcholine by acetylcholinesterase)
Brought back into presynaptic neuron using reuptake carriers (such as in serotonin, dopamine, norepinephrine)
Diffuse out of cleft (such as nitric oxide)

41
Q

Sensory (afferent) and motor (efferent) neurons

A

Transmit sensory info from sensory receptors to brain and spinal cord; transmit motor info from brain and spinal cord to muscles and glands

42
Q

Interneurons

A

Found between other neurons, most numerous type of neuron, linked to reflexive behavior, often in brain and spinal cord

43
Q

Central nervous system

A

Consists of brain and spinal cord

44
Q

White and gray matter

A

Consists of axons encased in myelin and is deeper in brain; consists of unmyelinated cell bodies and dendrites

45
Q

Four regions of spinal cord

A

Cervic, thoracic, lumbar, sacral

46
Q

Spinal cord

A

Protected by vertebral column, white matter on outside of cord, gray matter deep inside

47
Q

Dorsal root ganglia

A

Contains cell bodies of sensory neurons, which bring info from periphery and enter on dorsal side of cord, while motor neurons exit on ventral side

48
Q

Peripheral nervous system

A

Nerve tissue and fibers outside of brain and spinal cord, including pairs of spinal nerves and 10 of 12 cranial nerves

49
Q

Somatic and autonomic nervous system

A

Sensory and motor neurons in skin, joints and muscles
Manages involuntary muscles associated with internal organs and glands (heartbeat, respiration, digestion, etc), regulates body temp

50
Q

Pre and postganglionic neurons

A

First neuron in autonomic nervous system, its soma is in CNS and its axon travels to ganglion in PNS
Second neuron in autonomic nervous system, stimulates target tissue (somatic nervous system only has one neuron)

51
Q

Parasympathetic nervous system

A

Conserves energy, resting, sleeping states, reduce heart rate, constrict bronchi, maintain digestion and exocrine secretions, constrict pupils, stimulate saliva, contract bladder (acetylcholine released by both pre and postganglionic neurons)

52
Q

Sympathetic nervous system

A

Activated by stress, increase heart rate, redistribute blood to muscles of locomotion, increase blood glucose concentration, relax bronchi, decrease digestion, dilate eyes, release epinephrine into bloodstream, stimulates sweating and piloerection, inhibit salivation, inhibit bladder contraction, stimulate orgasm (preganglionic release acetylcholine, postganglionic release norepinephrine)

53
Q

Monosynaptic reflex arc

A

Single synapse between sensory neuron and motor neuron, such as knee-jerk reflex

54
Q

Polysynaptic reflex arc

A

At least one interneuron between sensory and motor neurons, such as withdrawal reflex from stepping on a nail

MCAT Biology Review (10 decks)

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