Chapter 7 Nervous System Flashcards Preview

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Flashcards in Chapter 7 Nervous System Deck (91)
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1
Q

Nervous System

A

Sensory input

integration

motor output

2
Q

Sensory input

A

monitor changes occuring inside and outside the body

gather information

3
Q

Integration

A

process and interpret sensory input

decide if action is needed

4
Q

motor output

A

respond to integrated stimuli

activate muscles or glands

voluntary and involuntary

5
Q

Organization of Nervous System

A

Central Nervous system

Peripheral Nervous System

6
Q

Central Nervous System

A

brain and spinal cord

7
Q

peripheral nervous system

A

nerves outside the brain and spinal cord

cranial and spinal nerves

8
Q

Nerve functional classification

A

sensory (afferent) division

Motor (efferent) division

9
Q

Sensory nerves

A

nerve fibers that carry information to the CNS
and the central canal

10
Q

motor nerves

A

nerve fibers taht carry impulses away from the CNS

1 Somatic nervous system: voluntary, skeletal muscle

2: Autonomic nervous system: involuntary, smooth and cardiac muscle and glands

11
Q

Nervous tissue
structure

A

consists of neurons and neuroglia

12
Q

neurons

A

structural and functional unit of the nervous system and conduct nerve impulses

13
Q

neuroglia

A

supports cells that provide physical support, insulation and nutrients to neurons

14
Q

Support cells

A

astrocytes

microlia

ependymal cells

oligodendrocytes

satellite cells

schwann cells

15
Q

Astrocytes

A

abundant star chaped cells

form barrier between capillaries and neurons

control chemical environment of brain

16
Q

microglia

A

phagocytose bacterial cells anc cellular debris in the CNS

Remove debris

17
Q

ependymal cells

A

line cavities of the brain and spinal cord

circulate cerebrospinal fluid

18
Q

oligodendrocytes

A

wrap around nerve fibers (axons) in the CNS

poroduce myelin sheaths

19
Q

satellite cells

A

protect neuron bodies in ganglia of the peripheral nervous system

20
Q

schwann cells

A

form myelin sheath around axons in the PNS

21
Q

Neurons

A

Nerve cells

specialized to transimt nerve impulses

22
Q

Neuron regions

A

cell body

Dendrites

Axon

23
Q

Cell body

A

nucleus

large nucleolus

nissl substance

specialized rough ER

Neurofibrils maintain shape

24
Q

Dendrites

A

short highly branched cytoplasmic extensions

conduct signals toward the cell body

25
Q

axon

A

1 per neuron

arises from the axon hillock

may have many branches (collaterals)

trigger zone region that initiates action potential (impulse)

conduct impulse away from cell body to axon termials

terminals contain vessels with neurotransmitters

26
Q

axon terminals

A

separated by gap from next neuron

1 synaptic cleft: fluid filled gap between adjacent neurons

2 synapse: junction between nerves

27
Q

unmylenated axon

A

schwan cells surrounds region of several axons but does not form myelin sheath

28
Q

myelinated axon

A

in PNS schwann cells wrap around peripheral axons in jelly roll fashion

layers of cell membrane create myelin sheath, whitish fatty material

neurilmma: portion of schwann cell that contains most of the cytoplasm and nucleus (outer surface)

in CNS aligodendrocytes form the myelin sheath (no neurolemma)

Nodes of ranvier: gaps in myelin sheath

29
Q

Locatoin of neuronal cell bodies

A

most are located in CNS

1 gray matter: cell bodies and unmyelinated fibers

2 Nucleus: cluster of cell bodies within the white matter of CNS

30
Q

Ganglion

A

collectoin of cell bodies outside the CNS or in the PNS

31
Q

Functional classification of neurons

A

Sensory (afferent)

Motor (efferent)

Interneurons

32
Q

sensoru neuron function

A

most unipolar some bipolar

cell bodies in ganglia

carry impulses from sensory receptors to the CNS

receptor-specialized dendritic ending

cutaneous sensr organs

proprioceptors-dectect stretch or tension

33
Q

motor neuron function

A

multipolar neurons

cell body within the CNS

carry implulses from teh CNS to viscera, muscles and glands

34
Q

interneurons function

A

found in pathways within the CNS

multipolar

some cell bodies in nuclei of CNS

connect neurons

35
Q

Structural classification of Neurons

A

multipolar: many extensions from the cell body
bipolar: one axon and one dendrite
unipolar: short single process leaving the cell body

36
Q

functional properties of neurons

A

irritability: ability to respond to stimuli
conductivity: ability to transmit an impluse

37
Q

Cell membrane potential

A

potential difference across cell membrane

plasma membrane is polarized at rest

fewer + ions are inside the cell than outside

resting potential caries with cell type-40 to -90 mV

38
Q

Membrane potential cause

A

distributino of ions across plasma membrane

1 Na+ high outside cell, low inside

2 K+ low outside cell, high inside

negatively charged molecules: DNA, RNA, proteins

membrane permeable to Na+ and K+

Na+/K+ pump (2 Na+ out, 2 K+ in)

39
Q

Membrane potential changes

A

depolarization

repolarization

40
Q

membrane depolarization

A

membrane potential bnecomes less negative

Na+ channels open

K+ channels close

Na+ enters cell

41
Q

Membrane repolarization

A

membrane potential returns to resting membrane potential (RMP)

K+ channel opens

Na+ channel closes

K+ leaves cell

42
Q

Nerve impulses

Action potentials

A

rapid sequence of depolarization and repolarization

43
Q

Nerve impulse threshhold potential

A

membrane potential at which an action potential is genterated

stimuli from other neurons sum to bring membrane to threshold

44
Q

nerve impulse propagation

A

if the action potential starts it is propagated over the entire axon

if not enough it begins ar trigger zone and ends at axon terminals

45
Q

Nerve impulse

myelinated axons

A

action potentials occur only at nodes of ranvier

saltatory conduction: AP appears to jump from node to node

Fast 120m/sec

46
Q

Nerve impulse

unmyelinated axon

A

action potential travels along the entire plasma membrane

slow .5 m/sec

47
Q

Synapse

A

neurons not in direct contact

separated by small gap : synaptic cleft

48
Q

synapse structure

A

axon terminal of presynaptic neuron

synaptic vesicles filled with neurotransmitter

synaptic cleft

receptors on postsynaptic membrane

49
Q

synapse signal transmission

A

impulses not directly able to cross to another nerve

action potential causes vesicle to move to membrane

neurotransmitter is released from axon terminal

neurotransmitter diffuses across synaptic cleft

neurotransmitter binds to protein receptors on dendrite of next neuron, post synaptic neuron

to stop a signal the neurotransmitter is broken down

50
Q

Relexes

A

rapid predictable and involuntary response to stimuli

simplest neural pathway (reflex arc)

51
Q

reflex pathway

A

Sensory receptor-sensory neuron-interneuron-motor-neuron-effector

52
Q

Reflex types and regulation

A

somatic reflexes: effectors are skeletal muscles

autonomic reflexes:

                         smooth muscle regulation

heart and BP regulation

regulation of glands

digestive system regulation

53
Q

Brain anatomy

A

3 lbs

contains about 100 billion multipolare neurons

4 major sections

cerebrum, diencephalon, brain stem, cerebellum

54
Q

Cerebrum

A

2 cerebral hemispheres

paird left and right superior part of brain

connected internally by corpus callosum

includes more than half of brain mass

surface is made of ridges (gyri) and grooves (sulci)

55
Q

Lobes of cerebrum

A

fissures divide the cerebrum into lobes

frontal lobe

parietal lobe

occipital lobe

temporal lobe

56
Q

Frontal lobe

A

primary motor area:

voluntary control of skeletal muscle

sends impulses to skeletal muscles

Borca’s area:

motor speech

involved in our ability to speak

problem solving and language comprehension

57
Q

parietal lobe

A

somatic sensory area

receives and interprets impulses from the bodies sensory receptors

speech and language region

58
Q

Occipital lobe

A

visoin center

59
Q

Temporal lobe

A

olifaction (smell

Hearing

60
Q

Cerebrum layers

A

gray matter: outer layer in cerebral cortex composed mostly of neuron cell bodies

white matter: fiber tracts deep to the gray matter

tract: bundle of fibers (axons) within the CNS

Basal nuclei: regions of gray matter burried within the white matter

61
Q

Diencephalon

A

sits on top of the brain stem

enclosed by cerebral hemispheres

main parts: Thalamus and Hypothalamus

62
Q

Thalamus

A

surrounds third ventricle

relay staton for sensory impulses

transfers impulses to the correct part of cortex for localization and interpretation

63
Q

Hypothalamus

A

located under the thalamus

important autonomic nervous system center

helps regulate body temp

controls water balance

regulates metablolism

important part of the limbic system (emotions)

pituitary gland attached

64
Q

Brain stem

A

attaches to spinal cord

3 parts

Midbrain

Pons

medulla oblongata

65
Q

midbrain

A

mostly composed of tracts of nerve fibers

reflex center for vision and hearing

66
Q

pons

A

mostly composed of fiber tracts

modifies activity of respiratory centers in the medulla

67
Q

medulla oblongata

A

lowest part of brain stem

merges into spinal cord

includes important fiber tracts

contains important control centers

heart rate control, BP regulatoin, respiratory centers sets rate and depth of breathing, swallowing and vomiting

68
Q

Cerebellum

A

cooridinates skeletal muscle activity

helps maintain posture, balance and equilibrium

69
Q

CNS protection

A

scalp and skin

skull and vertebral column

meninges

cerebrospinal fluid

blood brain barrier

70
Q

meninges

A

3 connective tissue membranes covering brain and spinal cord

dura mater

arachnoid mater

pis mater

71
Q

dura mater

A

double layered external covering

periosteum: attached to inner surface of skull

Meningeal layer: out covering of brain

folds inward in several areas

72
Q

arachnoid mater

A

middle layer

web like

73
Q

Pia mater

A

clings to surface of brain and spinal cord

contains superficial blood vessels

74
Q

subarachnoid space

A

space between acrachnoid and pia mater

filled with cerebrospinal fluid

75
Q

Epidural space

A

space bewtreen meninges surrounding spinal cord and bonds of vertebral canal

filled with adipose and loos connective tissue

76
Q

cerebrospinal fluid

A

similar to blood plasma composition

formed by the choroid plexus, reabsorbed by arachnoid villi

watery cushion to protect brain

ciculated in subarachnoid space, ventricles and central canal of spinal cord

77
Q

Ventricles

A

4 interconnected cavities with in the brain filled with CSF

CSF flows through

78
Q

Hyrocephalus

A

CSF accumulates and exerts pressure on the brain if not allowed to drain

newborns

79
Q

Blood brain barrier

A

includes the least permeable capillaries of the body

excludes many potentially harmful substances

useless against:

fats and fat soluable molecules

respiratory gases (CO2 and O2)

alcohol

Nicotine

Anesthesia

80
Q

Spinal Cord

A

slender column of nerve fibers (tracts) and neurons

center for spinal reflexes

81
Q

Spinal cord surface anatomy

A

extends from the foramen magnum of skull to the first or second lumbar vertebra

31 pairs of spinal nerves arise from spinal cord

Cauda equina

anterior median fissure

posterior median sulcus

82
Q

Spinal cord internal anatomy

A

gray matter is mostly cell bodies

Dorsal (posterior) horns

Anterior (ventral) horns

Gray commissure surround the central canal

central canal is filled with CSF

83
Q

Spinal cord exterior

A

White mater-fiber tracts

ascending tracts carry sensory information to brain

descending tracts conduct motor impulses from brain to motor neurons

pathways between brain and spinal cord

84
Q

Spinal nerves

A

leave at each level of vertebra

dorsal roots: sensory fibers

sensory neurons found in dorsal root ganglia

ventral roots: motor fibers

motor neurons are found in the anterior horn

spinal nerve forms where posterior and anterior roots merge

85
Q

Peripheral Nervous System

PNS

A

Nerves and ganglia outside the CNS

cranial nerve arises from brain

spinal nerves arise from spinal cord

86
Q

nerve

A

bundle of neuron fibers

87
Q

nerve structure

A

neuron fibers bundled by connective tissue

endoneurium surrounds each fiber

groups are bound into fascicles by perineurium

fascicles are bound together by epineurium

88
Q

Autonomic Nervous System

A

portion of PNS that function automatically

2 neurons in series from CNS to effector

regulates activites of cardiac, smooth muscle and glands

89
Q

autonomic nervouse subdivisions

A

Sympathetic nervous system

Parasympathetic nervous system

90
Q

Sympathetic Nervous System

A

extraordinary situations-fight or flight

exercise, excitement, emergency and embarrassment

91
Q

Parasympathetic Nervous System

A

housekeeping activites (rest and repose)

digestoin, defacation and diereses