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Flashcards in Nervous system Deck (83)
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1
Q

The nervous system

A

responsible for controlling most body functions, enabling organisms to receive and respond to stimuli from their external and internal environments.

2
Q

Which is faster in relaying signals to the brain, the endocrine or the nervous system?

A

the nervous system. 100m/s in some cases

3
Q

neurons

A

specialized nervous tissue that convert stimuli into electrochemical signals.

4
Q

neuroglia

A

cells that support and protect the neurons

5
Q

Organs of the nervous system

A

brain, spinal cord, eye, ear, etc.

6
Q

What are the two divisions of the nervous system?

A

CNS, PNS

7
Q

What are the functional units of the nervous system?

A

neurons

8
Q

What are neurons composed of?

A

dendrites, cell body, axon

9
Q

dendrites

A

cytoplasmic extensions that receive information and transmit it toward the cell body

10
Q

cell body (soma)

A

contains the nucleus and controls the metabolic activity of the neuron.

11
Q

axon

A

long cellular process that transmits impulses or action potentials away from the cell body. sheathed with myelin.

12
Q

Myelin sheath

A

prevents leakage of signal from the axon and allows for faster conduction of impulses

13
Q

Nodes of ranvier

A

gaps between the segments of myelin where the action potential actually propagates through saltatory (hopping) conduction.

14
Q

Oligodendrocytes

A

Glial cells that protect the myelin sheath in the CNS. provide structural framework for the CNS

15
Q

Schwann Cells

A

Glial cells that protect the myelin sheath in the PNS. Aid in the myelination of some peripheral axons

16
Q

synaptic terminals

A

swellings in the axon ends. realease neurotransmitter via this into the synapse (synaptic cleft).

17
Q

Major cells of the CNS

A

Astrocytes, Oligodendrocytes, Microglia, Ependymal Cells.

18
Q

Major cells of the PNS

A

Satellite cells and Schwann Cells

19
Q

Astrocytes

A

CNS. Maintain the integrity of the blood-brain barrier, regulate nutrient and dissolved gas concentrations, and absorb and recycle neurotransmitters

20
Q

Microglia

A

CNS. remove cellular debris and pathogens

21
Q

Ependymal Cells

A

CNS. Line the brain ventricles and aid in the production, circulation, and monitoring of CSF

22
Q

Satellite Cells

A

PNS. Surround the neuron cell bodies in the ganglia

23
Q

Polarized neurons

A

Neurons are polarized even at rest because of unequal distribution of ions between the inside and outside of the cell.

24
Q

resting potential

A

the potential difference at rest between the extracellular space and the intracellular space. -70mV. inside of the neuron is more negative.

25
Q

Na+/K+ pump

A

Maintains the selective permeability of the neuronal cell membrane. Pumps 3Na+ out of the cell for every 2K+ it transports into the cell. Cell membrane is more permeable to K+ than to Na+.

26
Q

Action Potential

A

When cell body becomes excited and depolarized (inside less negative), to reach the threshold potential, then voltage-gated ion channels located in the nerve cell membrane open in response. Begins when the Voltage-gated Na+ channels open in response to depolarization, allowing Na+ to rush down electrochemical gradient into cell causing further depolarization. Process continues down axon toward terminal. Once the synaptic cleft is reached another voltage0gated channel opens for calcium. Ca triggers the endocytosis of synaptic vesicles containing neurotransmitters. ALL OR NONE. frequency and not magnitude

27
Q

Repolarization

A

Voltage gated K+ channels open allowing K to rush down its electrochemical gradient and out of the cell. Na+ channels close and the Pump pumps Na out of cell again. Return the cell to a negative potential.

28
Q

Hyperpolarizaton

A

cells gets more negative than necessary in the refractory period.

29
Q

What would cause a faster propagation of a signal down an axon?

A

Larger diameter and more myelination.

30
Q

effector cells

A

cells other than neurons that other neurons can communicate with. Muscle cells

31
Q

neurotransmitters

A

the nerve terminal contains thousands of membrane bound vesicles containing these chemical messengers. When released from pre synaptic cells, they bind to post synaptic cells on proteins. Can be removed from the synapse by being taken back up into the nerve terminal where it may be reused or degraded or it may be degraded by enzymes or it may diffuse into the synapse

32
Q

Effects of Curare

A

blocks post synaptic nicotinic acetylcholine receptors, such as those on muscles, so acetylcholine is unable to interact with them. This leads to muscle relaxation and paralysis by blocking the ability of muscle to constrict

33
Q

Effects of Boulinum toxin

A

prevents the release of acetylcholine from the presynaptic membrane and also results in paralysis

34
Q

Effects of Anticholinesterases

A

used as nerve gases and in the insecticide parathion. inhibit the activity of the acetylcholinesterase enzyme responsible for degrading acetylcholine released into the synapse. acetylcholine is not degraded and continues to affect the postsynaptic membrane. No coordinated muscular contractions can take place.

35
Q

afferent neurons

A

sensory

36
Q

efferent neurons

A

motor

37
Q

INterneurons

A

link sensory and motor neurons in the brain and spinal cord. cell bodies and nerve terminal in the same location.

38
Q

plexus

A

network of nerve fibers

39
Q

neuronal cell body clusters in the PNS

A

ganglia

40
Q

neuronal cell body clusters in the CNS

A

nuclei

41
Q

PNS comprised of?

A

Somatic and autonomic

42
Q

autonomic nervous system comprised of?

A

sympathetic and parasympathetic

43
Q

Outer portion of cell bodies in the brain

A

gray matter

44
Q

inner portion of myelinated axons of the brain

A

white matter

45
Q

Forebrain

A

telencephalon and the diencephalon

46
Q

telencephalon

A

forebrain. cerebral cortex (highly convoluted gray matter that can be seen on the surface of the brain. processes and integrates sensory input and motor responses and is important for memory and creative thought.) Olfactory bulb (center for reception and integration of olfactory input.)

47
Q

diencephalon

A

Forebrain. Thalamus (relay and integration center for the spinal cord and cerebral cortex.) Hypothalamus (controls the visceral functions such as hunger, thirst, sex drive, water balance, blood pressure, and temperature regulation. important role in the control of the endocrine system)

48
Q

MIdbrain

A

Mesencephalon. relay center for visual and auditory impulses. motor control

49
Q

Hindbrain

A

Rhombencephalon. cerebellum (helps to modulate motor imuplses initiated by cerebral cortex; balance, hand eye coordination, timing f rapid movements), pons (relay center for the cortex to cerebellum), medulla (breathing, heart rate, GI activity). all make up the brainstem

50
Q

Spinal Cord outer white matter area

A

motor and sensory axons

51
Q

spinal cord inner gray matter area

A

nerve cell bodies

52
Q

dorsal horn of the spinal cord

A

sensory information enters the spinal cord through this. The cell bodies of these axons are located in the dorsal root ganglia

53
Q

ventral horn of spinal cord

A

where all motor information exits the spinal cord.

54
Q

somatic nervous system

A

innervates skeletal muscles and is responsible for voluntary movements as well as reflex arcs

55
Q

autonomic nervous system

A

involuntary nervous system. includes both sensory and motor fibers. innervates cardiac and smooth muscles. blood pressure control, GI motility, excretion, respiration, and reproduction.

56
Q

sympathetic nervous system

A

fight or flight. uses norepinephrine.

57
Q

parasympathetic nervous system

A

rest and digest. vagus nerve. uses acetylcholine

58
Q

sclera

A

thick opaque layer covering the eyeball

59
Q

choroid layer

A

layer beneath the sclera. supplies the retina with blood. dark pigmented reduces reflection in the eye

60
Q

retina

A

contains photoreceptors that sense light

61
Q

cornea

A

bends and focuses light rights at the front of the eye.

62
Q

Pupil

A

Rays travel from the cornea through the pupil, whose diameter is controlled by the pigmented iris

63
Q

iris

A

responds to intensity of light in the surroundings.

64
Q

lens

A

light travels through pupil, then through the lens which focuses images onto the retina

65
Q

ciliary muscles

A

controls the shape and focal length of the lens.

66
Q

photoreceptors

A

transduce light into action potentials

67
Q

cones

A

high intensity illumination and are sensitive to color. absorb red, green, and blue wavelengths.

68
Q

rods

A

low intensity illumination and are important in night vision. Rhodopsin (the rod pigment) only absorbs a single wavelength.

69
Q

how do the photoreceptor cells synapse?

A

onto bipolar cells, which in turn synapse onto ganglion cells.

70
Q

Optic nerve

A

bundles of axons of the ganglion cells make up the optic nerve, which conducts visual information to the brain.

71
Q

blind spot

A

the point at which the optic nerve exits the eye

72
Q

fovea

A

small area above the blind spot that is densely packed with cones and it important for high-acuity vision.

73
Q

vitreous humor

A

jelly like. maintains shape and optical properties

74
Q

Aqueous humor

A

watery. fills the space between the lens and the cornea

75
Q

myopia

A

nearsightedness. image focused in front of the retina

76
Q

hyperopia

A

farsightedness. image is focused behind the retina

77
Q

astigmatism

A

irregularly shaped cornea

78
Q

cataracts

A

lens becomes opaque. light cannot enter the eye and blindness results

79
Q

glaucoma

A

increase in eye pressure because of blocking of the outflow of the aqueous humor, which results in optic nerve damage.

80
Q

Sound energy

A

pressure waves

81
Q

outer ear

A

auricle (external ear) and the auditory canal.

82
Q

middle ear

A

tympanic membrane, ossicles (malleus, incus, and stapes) oval window.

83
Q

inner ear

A

cochlea, vestibular apparatus (equilibirum)