8. The Nervous System

Question 1

what is the nervous system responsible for

Answer 1

communication between specific parts of the body

Question 2

what does the nervous system contain

Answer 2

brain
spinal cord
nerves
sensory organs

Question 3

what is the functional unit of the nervous system

Answer 3

neuron

Question 4

what is the neuron capable of doing

Answer 4

transmitting an electrical signal from one cell to another

Question 5

what are the 3 components to a neuron

Answer 5

cell body
axon
dendrites

Question 6

what do dendrites do

Answer 6

receive signal to be transmitted

Question 7

what is the path of the signal through the neuron once its received by the neuron and what happens there

Answer 7

signal passes through the cell body and action potential produced if it is great enough

action potential moves from cell body down axon

Question 8

where does an axon carry a action potential to

Answer 8

synapse

Question 9

what does the synapse do

Answer 9

pass action potential from one cell to next cell

Question 10

when action potential is generated down a myelinated axon what happens to the motion of the action potential

Answer 10

it jumps from one node of ranvier to the next

Question 11

what is the resting potential of the ceel outside and inside

Answer 11

outside = positive
inside = negativ (-70mV)

Question 12

why is there a difference in the resting potential of the cell inside and outside

2 reasons

Answer 12

1. membrane contains Na-K+ ATPase that pumps Na+ to outside of the cell and K+ to inside of cell

more Na+ is pumped outside than K+ inwards

2. K+ leaks out of the cell

Question 13

overall what is the charge on the outside and inside of the membrane

what does this create

Answer 13

positive charge gained on outside and loss of positive charge from inside

creates membrane potential

Question 14

what is the membrane potential the basis of

Answer 14

all conduction of impulses by both muscle and nerve fibres

Question 15

what is an action potential

Answer 15

disturbance in electric field across the membrane of a neuron

Question 16

what can a stimulus do to the membrane

Answer 16

can make the membrane suddenly permeable over and above a threshold potential

Question 17

what will an increased membrane permeability produced by the stimulus cause for the ions and membrane potential

Answer 17

influx Na+ ions

reversal of membrane potential as inside of cell becomes + and outside becomes -

Question 18

what is depolarisation

Answer 18

stimulus increases membrane permeability and causes influx Na+ ions

reversal of membrane potential as inside of cell becomes + and outside becomes -

Question 19

what happens after depolarization

what is this process called

Answer 19

nerve functions to reach its previous resting potential

Na+ channels close and voltage gated K+ channels open

repolarisation

Question 20

what does it mean that the action potential is all or nothing

Answer 20

membrane either completely depolarizes or no action potential is produced

Question 21

what does the all or nothing principle mean for an action potential to be generated

Answer 21

stimulus must be greater than the threshold stimulus

Question 22

what happens at a synapse

Answer 22

neural impulses transmitted from one cell to another via synapse

Question 23

impulses are transmitted in which 2 ways

Answer 23

electrically

chemically

Question 24

what are the 3 major steps that occur at the synapse

Answer 24

1. synaptic vesicles in terminal buttons of a sending neuron release neurotransmitters into synaptic space
2. neurotransmitters cross synaptic space to receiving neurons
3. after crossing the synaptic space the neurotransmitters fit into receptor sites located on dendrites or cell body of the receiving neurons

Question 25

what are the 3 types of neurons

Answer 25

interneurons sensory neurons/afferent motor neurons/efferent

Question 26

what do interneurons do

Answer 26

transfer signals from neuron to neuron

Question 27

what do sensory neurons do

Answer 27

receive signals from a receptor cell that interacts wit the environment sensory neuron transfers singal to other neurons

Question 28

what do motor neurons do

Answer 28

carry signals to a muscle or gland - effector

Question 29

what are the 2 main divisions of the nervous system

Answer 29

central and peripheral

Question 30

what is the CNS composed of

Answer 30

brain spinal cord

Question 31

what is the PNS composed of

Answer 31

all other nerves and ganglion in the body

Question 32

what is the PNS divided into

Answer 32

somatic and autonomic

Question 33

what does the somatic nervous system do

Answer 33

carries out sensory and motor functions

Question 34

is somatic nervous system responsible for voluntary or involuntary

Answer 34

voluntary as it can be conciously controlled

Question 35

what do motor neurons innervate

Answer 35

only skeletal muscle

Question 36

is autonomic nervous system responsible for voluntary or involuntary

Answer 36

involuntary

Question 37

what are the portions of the autonomic nervous system

Answer 37

sensory and motor portions

Question 38

what does the sensory portion of the autonomic nervous system do

Answer 38

receives signals from organs in the body

Question 39

what does the motor portion of the autonomic nervous system do

Answer 39

conducts signals that the sensory portion receives from the body organs to smooth muscle, glands and cardiac muscle

Question 40

what is the motor portion of the autonomic nervous system further divided into

Answer 40

sympathetic and parasympathetic systems

Question 41

what is the sympathetic nervous system what does it do to blood flow

Answer 41

fight or flight increases blood flow to muscles - increases heart rate reduce blood flow to stomach - constricts blood vessels

Question 42

what is the parasympathetic nervous system responsible for and what does it do to blood flow

Answer 42

rest and digestion decreases blood flow to muscle - decrease heart rate increases blood flow to stomach for digestion - dilates blood vessels

Question 43

what does the parasympathetic nervous system use as a neurotransmitter

Answer 43

acetylcholine

Question 44

what does the sympathetic nervous system use as a neurotransmitter

Answer 44

noradrenaline or adrenaline

Question 45

what are receptors for acetylcholine called

Answer 45

cholinergic receptors

Question 46

what are receptors for noradrenaline and adrenaline called

Answer 46

adrenergic receptors

Question 47

what is the lower brain composed of

Answer 47

medulla hypothalamus cerebellum

Question 48

what is the lower brain responsible for

Answer 48

involuntary activities such as respiration, emotions and pain/pleasure

Question 49

what is the higher brain composed of

Answer 49

cerebrum and cerebral cortex

Question 50

what is the higher brain responsible for

Answer 50

processing thoughts and storing memories

Question 51

what is the cornea

Answer 51

outer covering of the eye

Question 52

what does the cornea do

Answer 52

increases ability of eye to properly focus on light

Question 53

what is the sclera

Answer 53

white layer on outside of eye

Question 54

what does the sclera do

Answer 54

provide structure and protection for the inner components of the eye

Question 55

what does the pupil do

Answer 55

takes in light and allows eye to focus on objects in front of it

Question 56

what does the iris do

Answer 56

dilator pupillae muscles are used to dilate/contract the pupil this allows the eye to take in more/less of the light depending on the surrounding light levels

Question 57

what is the lens used for

Answer 57

focuses light that comes through the pupil

Question 58

where is the lens located and what is it held in place by

Answer 58

located behind the pupil held in place by the ciliary muscles which change shape of the lens so light can effectively be focused onto the retina

Question 59

what does the retina do

Answer 59

light focused by the lens will be transmitted onto the retina

Question 60

what is the retina composed of

Answer 60

layers of rods and cones

Question 61

what can rods and cones do

Answer 61

cones can distinguish between colors but rods cannot

Question 62

what is connected to the retina

Answer 62

optic nerve

Question 63

what is the choroid in terms of location

Answer 63

lies between retina and sclera

Question 64

what does the choroid do

Answer 64

provide blood supply to the eye

Question 65

what is the vitreous humor in terms of location

Answer 65

gel in back of eye

Question 66

what does the vitreous humor do

Answer 66

helps maintain shape of eye

Question 67

what is the aqueous humor and what does it do

Answer 67

watery substance that fills the front of the eye maintains the shape of the eye

Question 68

what are the 3 parts of the ear

Answer 68

outer, middle and inner ear

Question 69

what is the pinna/auricle

Answer 69

skin and cartilaginous flap on the outer part of the ear

Question 70

what does the auricle do

Answer 70

collects sound waves and channels them into the external auditory canal

Question 71

where does the middle ear begin

Answer 71

at the tympanic membrane

Question 72

what are the 3 bones that make up the middle ear

Answer 72

malleus incus stapes

Question 73

what do the 3 bones of the middle ear do

Answer 73

translate sound waves to the oval window

Question 74

after passing through the middle ear where do the sound waves go

Answer 74

enters the inner ear and moves into the cochlea

Question 75

what happens as the wave moves through the cochlea

Answer 75

alternating rise and fall in pressure move the vestibular membrane in and out

Question 76

what detects the movement of the vestibular membrane

Answer 76

hair cells of the organ of corti

Question 77

what happens once the sound wave movement is detected by the hair cells of the organs of Corti

Answer 77

transformed into neural signals which are sent to the brain

Question 78

what does the inner ear contain

Answer 78

fluid filled semicircular canals that are responsible for balance

Question 79

what do olfactory and gustatory sense involve regarding sensing different chemicals

Answer 79

chemoreceptors