nervous system and eye Flashcards
(84 cards)
1
Q
what is the reflex arc
A
stimulus-> receptor-> sensory neurones-> CNS-> motor neurone-> effector-> response
2
Q
how does a signal cross a gap between nerve cells
A
chemical
3
Q
what is a rapid response
A
reflex
4
Q
what is a nerve cell called
A
a neurone
5
Q
what transmits signal to the CNS
A
sensory neurone
6
Q
what is a gap between 2 nerve cells
A
synapse
7
Q
what is something detected by the nervous system
A
stimulus
8
Q
what detects a change in the surroundings
A
receptor
9
Q
what transmits signals away from the CNS
A
motor neurone
10
Q
what is homeostasis
A
the maintenance of a constant internal environment
11
Q
what are 3 examples of things homeostasis controls
A
internal body temperature, blood pH, CO2 content of blood
12
Q
how does homeostasis work
A
negative feedback- when something increases above the normal, the response decreases it back to the normal and vice versa
13
Q
what is a stimulus
A
a change in the environment
14
Q
what does a receptor do
A
detects the change in the enviaronment
15
Q
what does the sensory neurone do
A
transmission of electrical signals
16
Q
what does the motor neurone do
A
transmission of electrical impulses
17
Q
what is an effector
A
a muscle or gland
18
Q
what is the response
A
contraction or secretion
19
Q
what is the stimulus when a light flashes in your eye
A
flash of light
20
Q
what is the receptor when a light flashes in your eye
A
retina
21
Q
what is the sensory neurone when light flashes in your eye
A
optic nerve
22
Q
what is the CNS when a light flashes in your eye
A
brain
23
Q
what is the motor neurone when a light flashes in your eye
A
motor nerve to iris
24
Q
what is the effector when a light flashes in your eye
A
iris
25
what is the response when a light flashes in your eye
constriction of the pupil
26
what is the stimulus, sense organ and receptor for sight
light, eyes, retina
27
what is the stimulus, sense organ and receptor for hearing
sound, ears, cochlea
28
what is the stimulus, sense organ and receptor for taste
chemical, tongue, taste bud
29
what is the stimulus, sense organ and receptor for smell
chemicals in the air, nose, chemoreceptor
30
what is the stimulus, sense organ and receptor for touch
pressure, skin, sensory nerve endings
31
what is the stimulus, sense organ and receptor for balance
change in position, ear, semi circular canals
32
where are dendron and what do they do
at the end of a nerve cell, they carry nerve signals/impulses towards the cell body
33
where is the axon and what does it do
the axon is the middle tube going throughout the neurone, it carries nerve impulses away from the cell body
34
where is the myelin sheath and what does it do
it is the tube outside the axon, it covers and insulates the neurone
35
what are the 3 neurone types and what does each one do
sensory neurone- carries signals towards the CNS, motor neurones- carry impulses to the effectors, relay neurones- carry signals between the sensory and motor neurones
36
what is the advantages of fast reflexes
quick response to danger
37
how do electrical messages cross the synapse
electrical signals convert to chemical signals however it takes a while to convert
38
how are the chemical signals able to cross the synapse
diffusion
39
what are the chemical signals called
neurotransmitters
40
how are the neurotransmitters converted back into electrical impulses
attaches to the membrane on the next neurone and sets off the axon
41
what are the large folds on the outside of the brain called
the cerebral cortex
42
what is the bit on the back of the brain called
the cerebellum
43
what is the thing that connects the brain to the rest of the body called
the medulla oblongata
44
what is the cerebral cortex
largest part of the brain and the outermost layer is the cerebral cortex while the whole thing is the cerebrum
45
why does the cerebral cortex have folds and wrinkles
increases SA so more info can be processed
46
what is the cerebellum
the wrinkled ball of tissue below the rest of the brain at the back
47
what does the cerebellum do
combines sensory info from eyes, ears and muscles to coordinate movement
48
what does the medulla oblongata do
controls vitals E.g. breathing, also important for sleep and helps transfer messages from the brain to the spinal cord
49
where are the lobes located
in the cerebrum
50
what does the frontal lobe do
controls thinking, planning, organising, problem solving, short term memory and movement
51
what does the parietal do
interprets sensory info
52
what does the occipital lobe do
processes images from your eyes and links them to images stored in memory
53
what does the temporal lobe do
processes info from your senses and play a role in memory storage
54
what is an MRI
a type of scan that uses strong magnetic fields and radio waves to produce detailed images of the inside of the body
55
how has the brain been studied (3)
studying patients with brain damage, electrically stimulating different parts to see what happens, using MRI scans
56
what is an EEG
a recording of brain activity
57
how does an EEG work
small sensors attached to your scalp pick up electric signals produced when brain cells send messages to each other. these are then picked up by a machine and checked by a doctor to see if anything is unusual
58
what is the function of the retina
Contains receptor cells called rods and cones which are sensitive to light
59
what is the function of the fovea
maximum density of cone cells found here as most of the light is refracted here by the lens
60
what is the function of the sclera
tough outer coating to protect the eye
61
what is the function of the cornea
where 70% of the light is refracted into the eye
62
what is the function of the optic nerve
where the information from the receptor cells collects and the nerve impulses from the retina are carried to the brain
63
what is the function of the iris
control the amount of light entering the eye
64
what is the function of the ciliary muscles and suspensory ligaments
change the shape of the lens
65
ligaments don't contract and relax they
slacken and tauten
66
what is the function of the pupil
hole that lets light into the eye
67
what is the function of the lens
refracts the light onto the retina
68
what happens when your eyes are in dim light(5)
pupil dilation, radial muscles contract, circular muscles relax, amount of light entering eye increases, size of pupil increases
69
what happens when your eyes are in bright light(5)
pupil constriction, radial muscles relax, circular muscles contract, size of pupil decreases, amount of light entering pupil decreases
70
how do the eyes focus on near objects(4)
ciliary muscles contract, suspensory ligaments loosen, lens is thicker and refracts light rays strongly, rays of light converge on retina
71
how do the eyes focus on far objects(4)
ciliary muscles relax, suspensory ligaments tauten, lens is pulled thin and only slightly refracts light, rays of light converge on the retina
72
what is short sightedness called
myopia
73
what is myopia
short sightedness, can't focus on distant objects
74
how is myopia treated
concave lens
75
how is myopia caused(2)
eyeball too long, lens too thick
76
what is long sightedness called
hyperopia
77
what is hyperopia
long sightedness can't focus on close objects
78
how is hyperopia treated
convex lens
79
how is hyperopia caused(2)
eyeball too short, lens too thin
80
what is presbyopia and how is it treated(3)
old sight, can't focus on near objects, reading glasses(convex lens)
81
what causes presbyopia(2)
loss of elasticity in lens, weaker muscles
82
why does body temperature need to be controlled
for efficient enzyme activity
83
why does blood sugar levels need to be controlled
cells need to be provided with the right amount of energy
84
why does water content of blood need to be controlled
too much water moving in and out of cells will damage them
