The Nervous System Flashcards
1
Q
Function of the nervous system and the endocrine system (ductless glands)
A
The coordination of activities in the body in response to changes in the environment
2
Q
quickest means of communication within the body
A
the nervous system
3
Q
2 parts of the human nervous system
A
Central nervous system
Peripheral nervous system
4
Q
Central nervous system
A
brain and spinal cord
5
Q
Peripheral nervous system
A
Consists of cranial nerves and spinal nerves not in the central nervous system
6
Q
function of PNS
A
these neurons carry impulses to and from the CNS
7
Q
Recetors
A
sensory cells or sense organs that receive and respons to different stimuli
8
Q
some stimuli
A
chemical (smell and taste) thermal electrical mechanical (touch, sound, stretching) osmotic light
9
Q
2 places where receptors can be found
A
on the surface pf the body eg for touch
deep inside the body eg osmotic receptors for brain
10
Q
effectors
A
tissues or organs that respond to a stimulus and carry out some action eg. muscles or glands
11
Q
neuron
A
nerve cell
12
Q
what are neurons capable of?
A
carrying electrical impulses
13
Q
electrical impulses
A
provide a means of communication between receptors and effectors
14
Q
what link the receptors to the effectors
A
neurons
15
Q
3 types of motor neurons found in vertebrates
A
motor, sensory and interneurons
16
Q
motor neurons
A
carry impulses from the CNS to the effectors
17
Q
sensory neurons
A
carry impulses to the CNS from the receptors
18
Q
Interneurons
A
carry impulses within the CNS, connect sensory and motor neurons
19
Q
what does the cell body contain
A
nucleus, cytoplasm and other organelles
20
Q
2 functions of the cell body
A
produces neurotransmitter chemicals
controls the passage of impulses
21
Q
dendrites
A
short, branching fibres that pick up and carry impulses to the cell body
22
Q
Axon
A
a long fibre that carries impulses away from the cell body along the neuron or carries impulses to the effector
23
Q
function of schwann cells
A
produce the myelin sheath
24
Q
myelin sheath
A
white fatty layer around the axon
25
2 functions of the myeline sheath
protect the axon
| speed up the transmission of the impulse along the axon
26
Nodes of Ranvier
gaps in the myelin sheath where the axon is uncovered
27
function of the nodes of ranvier
speed up the transfer of impulses along the neuron
28
neurotransmitter swellings
swellings found at the end of the axon
29
function of neurotransmitter swellings
have vesicles that store neurotransmitter chemicals (released to carry an impulse from one neuron to another)
30
carriage of impulses in motor neurons
from the CNS to the effector organ
31
carriage of impulses in sensory neurons
to the CNS from the receptors
32
cell body in motor neurons
at one end of the axon
33
cell body in sensory neurons
somewhere along the neuron
34
vague location of cell body in motor neurons
inside the CNS
35
vague location of cell body in sensory neurons
outside the CNS in a ganglion
36
most cranial and spinal nerves
mixed nerves, contain both sensory and motor neurons
37
size of neurons
neurons in the brain are very small
| those in the PNS connecting the spine to the foot may be over 1m long
38
when does a nerve transmit an impulse?
when it is stimulated strongly enough
39
what is an impulse?
an electrical current that travels along the neuron from the dendrites to the neurotransmitter swellings
40
what does the transmission of electrical impulses involve
the movement of ions across the membrane of the neuron
41
do impulses require energy
yes
42
where to the impulses get their energy
ATP
43
3 main ions
sodium (Na+), potassium (K+) and chloride (Cl-)
44
threshold intensity
minimum strength of stimulus needed for a nerve impulse to be transmitted
45
what type of response is a stimulus
an all-or-nothing response
46
below threshold
no impulse at all
47
speed and strength of different impulses
all the same speed and strength
48
can a nerve impulse be stopped?
no
49
what speeds up the rate of impulse transmission
the myelin sheath
50
refractory period
short delay of a few milliseconds between the transmission of impulses
51
can impulses travel in different directions?
no, one direction only
52
do neurons have protoplasmic connections between them?
no
53
what do neurons have in place of protoplasmic connections
a region called the synapse where neurons come into contact
54
synaptic cleft
each synapse's tiny gap
55
what carries the impulses across the cleft?
neurotransmitters
56
3 examples of neurotransmitters
acetylcholine, serotonin, dopamine
57
where are neurotransmitters released from?
the neurotransmitter swellings
58
what occurs when an impulse arrives at the synapse
vesicles un the neuorotransmitter swellings release neurotransmitter into the synaptic cleft
59
what happens when the neurotransmitter has been released?
it diffuses across the synaptic cleft and generates an impulse in the next neuron
60
as soon as the neurotransmitter has worked?
it is broken down by an enzyme
61
at the end what happens to the neurotransmitters?
some are transported back into the neurotransmitter swellings and are reused
62
2 functions of the synapse
controls only one direction of the impulse, can travel in one direction only along a given pathway
Impulse can be blocked or enhanced here by certain chemicals (pain and psych meds)
63
what does the CNS do?
forms a bridge between sensory and motor functions of the peripheral nervous systems
64
top of brain
meninges
65
under meninges
cerebrum
66
bottom back of brain
cerebellum
67
bottom front tiny part of brain
pituitary gland
68
above pituitary gland
hypothalamus
69
under cerebellum
medulla oblongata
70
is the CNS full?
no its hollow
71
what are the cavities of the brain and spinal cord filled with
cerebro-spinal fluid
72
cerebro-spinal fluid
fluid that is filtered from the blood
73
function of cerebro-spinal fluid 2
brings food, O2, etc. to nerve tissue
removes waste from the nerve tissue
protects the CNS as a shock absorber
74
what covers the CNS
3 protective membranes called the meninges
75
where is cerebro-spinal fluid found
between the 2 inner membranes
76
what encloses the CNS
the axial skeleton
77
what protects the brain?
the cranium
78
what protects the spinal cord?
the vertebral column
79
3 main parts of the brain
forebrain, midbrain and hindbrain
80
main part of the forebrain
cerebrum
81
largest part of the brain
cerebrum
82
what is the cerebrum divided into
left and right cerebral hemispheres
83
outer grey part of cerebrum
cerebral cortex
84
what is the cerebral cortex made up of?
cell bodies and dendrites
85
most complex part of the brain
cerebral cortex
86
inner white part of the cerebrum
medulla
87
what is the medulla composed of?
axons with myelin sheaths
88
functions of cerebrum
voluntary movements, personality, memory, learning, hearing, vision, speech and language, intelligence
89
part of the forebrain below the cerebrum
hypothalamus
90
where is the main site of homeostasis
hypothalamus
91
functions of hypothalamus
hunger, thirst, osmoregulation, regulation of body temperature
92
what is connected to the hypothalamus
the pituitary gland
93
is the pituitary gland part of the brain
no
94
what is the pituitary gland part of
the endocrine system
95
what part of the brain is the cerebellum part of `
hind brain
96
second largest part of the brain
the cerebellum
97
2 functions of the cerebellum
muscular co-ordination (movement, balance)
| hand-eye co-ordination
98
what part of the brain is the medulla oblongata?
hindbrain
99
what does the medulla oblongata do
connects the brain to the spinal cord
100
functions of medulla oblongata
involuntary muscles (eg.intercostals), breathing swallowing salivation vomiting blood pressure
101
from where does the brain recieve impulses
from sensory organs of the body
102
what does the brain do as a result of sensory impulses
sends out impulses to the effectors and causes them to react
103
in its association centres and motor areas, what does the brain do?
it coordinates the various stimuli from several receptors before sending out impulses to the appropriate affectors
104
what stores information and why?
the forebrain, so that behaviour can be modified as a result of past experience (memory and learning)
105
to what is the spinal chord attached?
the medulla oblongata
106
2 components of the spinal chord
central core of grey matter
| outer layer of white matter
107
grey matter
cell bodies and dendrites
108
white matter
axons with myeline sheaths
109
outside of spinal chord
membrane called the meninges
110
what pass between the vertebraun
pairs of spinal nerves
111
what attaches the nerve to the spinal cord
2 roots; the dorsal and the ventral
112
what are spinal nerves
mixed nerves
113
sensory neurons in spinal cord
enter the spinal cord via the dorsal root
114
motor neurons in the spinal cord
leave via the ventral root
115
2 functions of the spinal cord
spinal reflexes eg.stretches
| transmits impulses to and from the brain
116
Reflex action
an automatic response to a stimulus that is not under conscious control
117
2 reflex actions
knee jerk
| blinking
118
advantage of refelx actions
fast responses that protect the body from damage
119
structural basis of reflex action
the reflex arc
120
Mechanism of spinal reflex action:
| first step
receptor cell is stimulated
121
Mechanism of spinal reflex action:
| once receptor cell is stimulated
impulse moves along sensory neuron into spinal cord
122
Mechanism of spinal reflex action:
| once the impulse has gotten to the spinal cord
impulse is passed to an interneuron in the spianl cord
123
Mechanism of spinal reflex action:
| once impulse reaches interneuron
impulse moves along interneuron to a motor neuron
124
Mechanism of spinal reflex action:
| once impulse has gotten to motor neuron
impulse moves out of the spinal cord along a motor neuron to the effector
125
Mechanism of spinal reflex action:
| when impulse gets to effector
effector is stimulated and reacts
126
simple reflex actions
automatic and involuntary and do not involve the brain
127
2 simple reflex actions
withdrawal of hand after pricked with a pin
| iris-pupil reflex
128
1 disorder of the nervous system
parkinson's disease
129
cause of parkinson's disease
not enough dopamine produced due to degeneration of part of the brain
130
symptoms of parkinson's disease
hand tremor
| rigid and stoops and walks with small shuffling steps
131
3 corrective measurements of parkinson's disease
drug treatment
exercise
stem cells
132
exercise for parkinson's disease
most important therapy used to strengthen all of the muscles
