Module 3 - Topic 1-2: The Nervous System Flashcards Preview

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Flashcards in Module 3 - Topic 1-2: The Nervous System Deck (115):
1

functions of nervous tissue

acquire and transmit sensory information
process information
activate an appropriate response

2

Central Nervous System

processing and control of information
brain and spinal cord

3

Peripheral Nervous System

nervous tissue outside CNS
consists of nerves carrying information to and from CNS

4

Afferent

sensory - division of peripheral nervous system
carrying information from body to CNS

5

Efferent

motor - division of peripheral nervous system
carrying information away from CNS towards effector organs

6

Somatic

division of efferent
voluntarily and form synapses with skeletal system

7

Autonomic

division of efferent
involuntarily
send efferent signals from brain to smooth muscle, cardiac muscle and glands

8

Sympathetic

division of autonomic
fight or flight
activate target organs

9

Parasympathetic

division of autonomic
contentment, relaxation, digestion
inactivate target organs

10

Ganglia

collection of nerve cell bodies
lie outside the CNS
play important role in autonomic system

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nervous tissue

consists of 2 types of cells
neuronal cells
glial cells

12

Neuronal cells

transmit signals throughout nervous system
electrical currents which pass from one end of cell to the other

13

how neuronal cells communicate

synapses

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neurotransmitters

transmission of information across synapse, mediated by the release of chemical meesengers

15

Neuron makeup

soma
several dendrites
axon

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soma

basic metabolic part of the nerve cell

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dendrites

extension of cell that receives information

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axon

transmits info away from cell body

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Glial cells

dont transmit info but instead support the survival and function of other neuronal cells

20

Neuroglia

outnumber neurons 10 to 1
makeup 50% of brain mass

21

Astrocytes

create cohesion of central nervous tissue
hold things together and maintain structural relationships

22

Oligodendrocytes

form myelin

23

Ependymal cells

epithelial lining for cavaties
small amounts of cerebrospinal fluid is formed by secretion

24

Microglia

migrate into nerve tissue from blood stream
protective immune function

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Satellite cells

formed in peripheral ganglia and supports the cell bodies

26

Schwann cells

PNS, involved in peripheral myelin formation and the formation of neurilemma

27

Myelin

phospholipid produced when plasma membrane becomes wrapped around axon of neuronal cell

28

myelin sheath gaps

have lots of gaps that speed up nerve impulse conduction

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membrane potential

voltage that exists across plasma membrane

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voltage

difference in electrical charge

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major molecules responsible for membrane potential

sodium and potassium

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sodium potassium pump

removes 3 sodium ions and replaces with 2 potassium ions

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Plasma membrane - potassium

more permeable to potassium so there is an unequal exchange of positively charged ions

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unequal charge

inside has a less positive state than outside

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resting neuron potential

negative
-70mv

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depolarisation

decrease in membrane potential, less negative

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Repolarisation

return of cell to its resting potential

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Chemically gated channel

opens in response to chemicals binding to receptors

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Voltage gated channels

open in response to change in membrane potential

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Initial Change

takes place when a nerve is activated

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Action potential

when a receptor potential is strong enough to reach a region, trigger zone, action potential is generated

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trigger zone - location

generally located in neuron near start of axon

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Action potential - size

large
cause all or nothing changes in membrane potential

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action potential - gating

voltage gated and only open if threshold change in membrane potential is reached

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Repolarisation phase - action potential

eventual closing of voltage gated Na+ channels and opening of voltage gated K+ channels, allowing membrane potential to return to resting state

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Myelin - purpose

increases rate at which action potential travels down axon by insulating selected portions of the axon

47

Action potential - location

generated at the gaps within nerve sheath

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Myelin fibres

much faster

49

Non myelin fibres

much slower

50

CNS function

process sensory info and generate appropiate responses

51

White matter

mostly nerve fibres (axons) and appear white due to myelin

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Grey matter

nerve cell bodies, no myelin present

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Brain matter makeup

outer - grey
middle - white
inner - grey

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Spinal cord matter makeup

outer- white
inner - grey

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Cerebrospinal fluid

CNS floats in watery nutrient rich bath
produced by specialised clusters of tissue

56

Choroid plexuses

specialised clusters of tissue that make CFS and hang from roof of ventricles
knot of porous blood capillaries surrounded by ependymal cells

57

ependymal cells

process the filtrate passing and aid in formation of blood brain barrier

58

CSF

protects brain from injury
nourishes brain and removes wastes
carries hormones

59

constant motion of CSF

aided by movement of long cilia of ependymal cells lining ventricles

60

Meninges

three covering layers of connective tissue
dura mater
arachnoid matter
pia matter

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Dura Matter

hard tough outermost covering connected to the inside of the skull

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Arachnoid matter

middle covering, spider like

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Pia Matter

tender, thin innermost covering attached to brain

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sub arachnoid space

wide space between arachnoid and pia membranes where CSF flows

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Hydrocephalus

when fluid accumulates and exerts pressure on brain

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Brain subdivisions

left and right cerebral hemisphere
diencephalon
Brain stem
cerebellum

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The left and right hemisphere

consist of outer cerebral cortex of grey matter
inner region of cerebral white matter
island of additional grey matter (basal nuclei)

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Cerebral cortex

controls all activities of the body
can be divided into lobes
outer: grey
middle: white matter
inner: basal nuclei - grey

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Frontal lobe

back of brain
consciousnesss and personality
primary motor region

70

Parietal lobe

at the side
Primary sensory region
every part mapped to different body part

71

temporal lobe

at temple
primary audio centre

72

occipital lobe

infront of eyes
primary vision region

73

cerebral cortex functional areas

sensory areas
motor
association

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Sensory areas

percieves information

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motor area

control of voluntary movement

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association areas

integrate multiple pieces of info from various stimuli

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commissural fibres

enables communication between left and right hemispheres

78

association fibres

enables communication with each hemisphere

79

projection fibres

links cortex to rest of NS

80

Basal nuclei

influences motor function
consists of caudate nuclei, putamen, globus pallidus

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lentiform nucleus

putamen and globus pallidus

82

corpus striatum

caudate nucleus and lentiform nucleus

83

Diencephalon

2 lobed structure at middle brain
on top of brain stem
made of 3 components
thalamus
hypothalamus
epithalamus

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Thalamus

inner
relay station to higher cerbral cortex,
involved in memory processing

85

Hypothalamus

below
control centre of homeostasis
regulates many important functions

86

Epithalamus

back of diencephalon and contains pineal gland

87

pineal gland

secretes melatonin that controls sleep wake cycle and mood

88

Brain stem

critical to survival
contains specialised autonomic centres that controls heart rate, blood pressure, breathing

89

Brain stem - midbrain

top of stem - middle of brain

90

Brain stem -pons

bridge

91

Brain stem - medulla oblongata

lower part of stem
controls important functions
relay station of hypothalamus

92

Cerebellum

sits underneath cerebrum
coordinates motor activities
grey matter with thin branches of white matter
in charge of coordination

93

spinal cord - protection

protected by bone, coverings and CSF

94

spinal cord - function

two way conduction pathway

95

anterior tips of wing

ventral horns

96

arrangement of grey matter in spinal cord

butterfly shaped

97

posterior tips of wings

dorsal horns

98

lateral wings

to the side, located in thoracic and superior lumbar regions

99

Ventral horns

mainly somatic motor nerve cells with efferent fibres leaving the spinal cord via ventral root

100

Dorsal horns

somatic sensory nerve afferent fibres travelling from organs to CNS enter spinal cord

101

lateral horns

autonomic nerve cells which stimulate visceral organs
stimulate flight or fight `

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outside spinal cord - ventral and dorsal

they fuse together to form on spinal nerve for each side of body

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Ascending nerve fibres

carry sensory impulses towards higher centres

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Descending nerve fibres

carry impulses from brain to lower parts

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Traversing fibres

carry info from one side to the other

106

Gyrus

brain ridges

107

Sulcus

grooves in brain, folds back on itself to form grooves

108

Broca's area

speaking (frontal)

109

Wernicke's area

processing and comprehesion
temporal

110

Corpus Callosum

thick bundle of nerve fibres that hold brain hmispheres together
carries impulses and has many axonss

111

limbic system

emotional response
ring of structures
encircles the upper part of brain stem, corpus callosum and temporal lobes

112

Hippocampus

memory centre

113

olfactory bulbs and stalks

sense smell

114

Amygdala

instinctive behaviour and rage centre
response to pheromones

115

interneuron

link sensory and motor neuron that doesnt go through brain