B5 Flashcards

1
Q

what does the CNS protect us from

A

protects organisms from harm by responding to changes in the environment

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2
Q

what are the CNS components

A

1)the brain
2)the spinal cord

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3
Q

what do neurones do

A

carry electrical impulses between receptors, the CNS and effectors

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4
Q

what does the CNS do

A

coordinates the response of effectors and coordinates responses to stimuli

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5
Q

what are effectors

A

effectors bring about actions in response to a change in the internal end external environment, like muscles contracting and

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6
Q

what is a synapse

A

synapses are gaps between neurones and can be found at each junction if a reflex arc

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7
Q

what are neurotransmitters

A

chemicals that diffuse across synapses and bind to receptors on the next neurone

they initiate electrical impulse into the next neurone

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8
Q

reflex action

A

an unconscious response that allows a person to respond to a dangerous situation rapid and automatic, by a reflex arc

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9
Q

components of a reflex arc

A

1)stimulus
2)receptor
3)sensory neurone
4)coordinator
5)motor neurone
6)effector
7)response

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10
Q

what happens when the nerve impulse arrives at the synapse

A

the electrical impulse reaches the end of the neurone before the synapse

This triggers the release of chemicals called neurotransmitters

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11
Q

how do electrical impulses pass on

A

the neurotransmitters diffuse across the synapse

The neurotransmitters bind to receptors on the dendrites of receiving neurone

The presence of the neurotransmitter causes the production of an electrical impulse

when enough receptors have been filled a threshold is reached and a electrical impulse made in receiving neurone

after, the neurotransmitter is detaches from membrane of receiving neurone and reabsorbed back into the original neurone

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12
Q

what is a stimulus

A

A stimulus can be any change in the environment to which the body needs to respond.

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13
Q

what is a receptors

A

Receptors are found all over the body.
They detect the change in the environment and initiate (start) a signalling process within the body.
The signal is picked up by a neurone (nerve cell).

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14
Q

what are neurones

A

There are three types of neurone

part of the nerve

a nerve cell

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15
Q

factors that effect reaction time

A

Caffeine and exercise are factors that could affect human reaction time

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16
Q

what is the medulla

A

This part is responsible for unconscious activities (e.g. breathing and heartbeat)

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17
Q

what is the cerebral cortex

A

This part is responsible for conscious thought (e.g. memory, language and intelligence).

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18
Q

what is the cerebellum

A

This part is responsible for the muscle coordination.
The cerebellum is important for movement, posture, balance and speech.

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19
Q

what are MRI scanners

A

MRI stands for Magnetic Resonance Imaging.
MRI scanners have allowed us to learn which areas of the brain are active during different activities, such as moving, speaking and listening.

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20
Q

what is electrical stimulation

A

Electrical stimulation has also allowed us to treat certain disorders of the brain.
Because the nervous system communicates using electrical impulses, electrical stimulation is used to help treat conditions such as Parkinson’s disease (causes tremors).

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21
Q

what is accommodation

A

lens of the eye changing shape to focus on objects

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22
Q

how can eye defects be treated

A

Both myopia and hyperopia can be treated using glasses fitted with lenses that refract light rays to allow the image to form on the retina. Contact lenses and laser eye surgery can also correct these issues.

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23
Q

what is myopia

A

short sighted

Myopia happens when rays of light focus in front of the retina.

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24
Q

what is hyperopia

A

Hyperopia happens when rays of light focus behind the retina.
long sighted

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25
hwo does the body maintain this constant internal environment
homeostasis
26
what is homeostasis
to maintain a stable constant internal environment uses systems of receptors and effectors
27
why is it important to keep conditions constant
so that other systems are not interrupted by changes in the surroundings
28
what does the body maintain automatically
ensures that all its inputs and outputs are in balance by regulating the amount of blood sugar, water, ions, and temperature the body needs to ensure it that there is enough sugar to supply all your cells with a constant amount of energy
29
what affects the amount of sugar available for you body
the amount and type of food
30
why do the cells need sugar
so that there is enough energy to carry out respiration to release energy
31
what is osmoregulation
the regulation of the amount of water you have in your body
32
how does water leave the body
lungs through breathing out skin through sweat and the kidney through urine
33
how does the body replace lost water
the body needs to replace lost water and it tell you that it needs water when you are thirsty
34
how are ions lost
through sweat and urine
35
what do the kidneys regulate
they monitor the volume of water and ions to be released
36
what is thermoregulation
regulating body temperature one of the most important things the body does
37
why is thermoregulation important
to allow enzymes to work at their optimum rate
38
what are enzymes
they are chemicals that allow reactions to happen at body temp of 37 degrees
39
what would happen with out the help of enzymes for the chemical reactions to happen
they would need much higher temperatures to work
40
when do enzymes work
they are very sensitive and only work when all the conditions are right
41
how does the body regulate, sugar, ions, water and temperature
communication negative feedback
42
what is negative feed back
around the body there are receptors that pick up changes in the environment once they detect a change they send information to a processing centre usually the brain always does the opposite
43
what does the processing centre do (the brain)
coordinates a response
44
what is the response from the brain
to send a message to the effectors which are either glands or muscles these will do something about the change to make the conditions back to normal
45
what are glands
organs that secrete hormones
46
what are hormones
chemical messengers that affect how organs work
47
what are animals with a backbone called
vertebrates
48
where can the information the CNS come from
eyes kidneys skin entire body
49
how are the spinal chord and the body organs connected
through nerves
50
what are nerves
made up of neurones
51
what are sensory neurones
The sensory neurone carries the signal in the form of an electrical impulse to the central nervous system (CNS). transmit signal from receptors to the CNS
52
what are relay neurones
The relay neurone (in the CNS) relays the electrical impulse from the sensory neurone to the appropriate motor neurone. carry’s impulses between neurons
53
what are motor neurones
The motor neurone is another type of nerve cell that carries the electrical impulse from the CNS to an effector.
54
what is the peripheral nervous system
the network of nerves that connects to body organs
55
how might the body respond to a stimulus
voluntary - brain has to think of a respons involuntary - body reacts automatically
56
what are touch receptors
on the skin they respond to a stimulus that touches the skin
57
how does the sensory neurone carry impulses to the CNS
through electrical signals that move rapid along sensory neurone to spinal cord then to the brain
58
how does the body move after the brain has made a decision
sends a new electrical signal by a motor neurone to body part it wants to move muscles carry out response
59
sequence of events for a voluntary response
-stimulated receptor -sensory neurone - spinal chord - brain to make a decision -sends out new electrical impulse (response signal) by the motor neurone - to the effector - effector carries out response
60
what is the sequence of events in an involuntary response (reflex response)
-stimulated receptor -sensory neurone -relay neurone in spinal chord -connected to motor neurone -effector carries out response
61
what are the components of a neurone
very long have a insulating sheath (myelin sheath) to stop electrical impulses jumping onto other neurones - the insulation allows impulses to travel across the neurone in little hops which makes it travel faster dendrites branch out from cell body at one end the long wire part is called axon when it’s carrying signals away from the body -but called dendron if it’s carrying signals towards the body
62
what happens when the electrical impulse reaches the terminal of the axons
causes vesicles in axon to move to the outer edge and release neurotransmitters into the synapse
63
how are receptors on receiving neurone specific
specific to a particular neurotransmitter
64
how can you interfere with neurotransmission at a synapse
drugs can block neurotransmitter receptors so signal can’t be passed on can cause death
65
how can you affect re absorbtion of neurotransmitters into the original neurone
with drugs and further messages can’t be sent
66
why does the body used electrical signals and chemical neurotransmitters
many advantages -1if only electrical the messages would be too fast -false signals which would trigger other messages -by using neurotransmitters the signal has to reach a threshold before they get passed on - and they ensure signal only travels in 1 direction (electrical circuits they can travel in either)
67
what are the advantages of reflex actions on an organism
sustains mess damage live longer quick
68
how are we aware of reflex actions
signals are also sent to the brain this is why there is a delay in carrying out reflex action and geeking pain
69
how are cells involved in reflex actions specialised
they transmit electrical impulses quickly sensory and motor neurones are long relay neurones are much shorter
70
why are synapses important
prevent insignificant signals causing us to respond when we should not
71
examples of reflex actions
hand moves away from hot object pupils get smaller when you move from a dark place to a light place adrenaline is produced when you are scared
72
what do glands do
secrete hormones
73
stimulus examples
temp change light change
74
what organisms depend on reflexes
more simple than complex otherwise they would die because they hunt and hide automatically
75
why does the pupil contract when we move from dark places to light
restricts the amount of light entering the eye called the pupil reflex helps prevent damage to light sensitive cells in the retina
76
what is the rooting reflex in babies
a baby turns toward an object that touches its cheek to find the milk
77
what is the sucking reflex
if an object is placed in a babies mouth it will automatically suck
78
what is the stepping reflex in newborns
a baby will make stepping movements when held up
79
types of sense organs
light is detected by eyes sound is detected by ears pressure is detected by the skin
80
what halpens if a stimulus is too weak
a signal is sent because the impulse doesn’t reach the threshold
81
why are thresholds improved
would be difficult to differentiate genuine signals and background level of activity
82
what does the retina contain
thousands of light receptor cells
83
what receptors detect colour in the retina
cone cells
84
what receptor cells detect brightness in the retina
rod cells
85
where does the signal go to when the receptor cells in the eye detect light
passed through the optic nerve
86
what are organisms that use nerves and electrical impulses
they are multi cellular
87
do simple organisms have nerves
no, they can’t respond to changes in an environment the same way a multicellular animal can
88
why do we want to understand how the brain works
we can help people recover from injuries develop better methods of treatment better understanding of what it means to be a person (what makes you, you
89
what is the brain
processing centre of CNS it coordinates a response after processing and interpreting nerve signals from whole of the body
90
what is the cerebral cortex
-the outermost part of the brain -wrinkled - concerned with intelligence memory and consciousness (awareness of yourself
91
how did we understand more about the brain overtime
through injuries and their consequences
92
how can we survive if we damage our brain substantially
if the part of the brain damaged doesn’t control any part of the body
93
why is mapping the brain by the recording of the effects of injury’s bad
it’s hit and misss it’s limited to the few people who have had a head injury
94
what is an invasive method of understanding the brain
stopping parts of the brain and see the effects - very invasive process - only done on patients who already have a bad injury and/or voluntarily
95
what is a non invasive technique for understanding the brain
being improved all the time by new developments in physics -magnetic fields and electricity to stimulate the brain -electrodes being attached to the scalp - EEG -MRI
96
what happens during magnetic fields and electricity to stimulating the brain
powerful electromagnetic fields that change direction tens of thousands times a second can interfere with parts of the brain if a high powered magnetic field is positioned over the speech part of the brain, a patient starts to mess up their words this is because the magnetic fields interfere with the signals being sent to that part of the brain
97
how do electrodes being attached to the scalp work - EEG
they detect and measure changes of electric current inside the brain when someone carries out an activity parts of the brain involved show electrical activity and can be identified
98
what is MRI
an improvement from EEG to be more specific stands for magnetic resonance imaging uses strong magnetic field and radio waves person is placed in chamber and a magnetic field, which changes direction thousands of times a second is employed over the chamber with the right MRI scanner we can identify the parts of the brain active when we think about carrying out an action
99
what do animals that can see have
survival advantage they have eyes to detect light reflected from objects
100
what is the sclera
-white -tough -holds eyeball together -outermost part of the eye -stops light from entering the eye, apart from front of the eye which is transparent
101
what is the cornea
refracts the light rays so that the light rays focus on the retina to produce the image front of the eye
102
what is the iris
behind the cornea ring of muscle that: -contracts to minimise the amount of light entering the eye -relaxes to let in more light
103
what is the pupil
the hole in the middle of the iris it is black because the light that hits the retina is all absorbed
104
aqueous humour
transparent jelly between cornea and the iris gives shape to front of eye
105
what is the lens
behind the iris and attached to muscles these muscles can contract and relax to alter the thickness and the length of the lens enables fine focusing of the image on the retina
106
what happens when you alter the lens shape
alters the amount of refraction of light entering the eye but most of the refraction takes place at the cornea
107
what is the vitreous body
inside main part of the eyeball, behind the lens another transparent jelly (a bit thicker) give the whole eyeball it’s shape
108
what is the retina
made up of millions of cells -some are designed to trigger a nerve signal when stimulated by light of a specific wavelength -cone cells which detect red, blue and green light (colour) (found in centre of retina) -rod cells detect intensity of light and are scattered over the entire inside of the eye
109
what is averted vision
example: -you see faint stars better if you don’t look directly at them -because it allows the light to land on the part of the retina that contains rod cells but cone cells -allows you to detect faint light and let’s you see the faint stars more clearly
110
light journey into the eye
-hits cornea and gets refracted -aqueous humour -pupil surrounded by iris -into the lens and gets refracted a bit more -vitreous body -then the retina landing on rod or cone cell -cell sends message to the brain by the optic nerve
111
how is long/short sightedness caused
the eyeball or the lens being the wrong shape
112
how is short sightedness caused
if the eyeball is too large light is focused in the space infront if the retina
113
how is long sightedness caused
if the eyeball is too small light entering the eye is focused behind the retina
114
how does the body know the temperature of the body
receptors in the brain monitor the temperature of the blood receptors on skin that receive information about the external temperature
115
what is the hypothalamus
section in brain location of the thermoregulatory system sets up a series of electrical impulses sent to effectors around the body
116
what is the thermoregulatory system
coordinates responses to temperature
117
why does the body need to stay at 37 degrees
so chemical reactions can happen at their optimum rate
118
why are enzymes useful
they are chemicals that allow reactions to happen at low temperatures they are very sensitive and only work in very specific conditions (37 degrees
119
what are the effectors that bring temperature down
blood vessels and sweat glands
120
what happens to blood vessels near the surface on the skin when hot
the blood vessels that supply the capillaries near the surface of the skin dilate makes you look redder this is called vasodilation
121
what does vasodilation do
higher rate of blood flow to the surface of the skin this increases the rate of heat loss
122
what layer of skin produces sweat glands
sweat glands in the dermis layer
123
how does sweat cool you down
the water in the sweat evaporates using heat energy from your skin which cools you down
124
what happens after you lose water through sweat
need to drink more to replace the loss of water
125
what happens to your blood vessels when you are cold
blood vessels near surface of skin constrict this reduces rate of blood flow and prevents heat loss called vasoconstriction
126
what is shivering
shivering is muscles contracting quickly for your muscles to contract you need to supply them with energy by respiration every time cells respire they give out heat energy
127
why do we shiver
to increase respiration in cells which increase heat supply
128
why do we get goose bumps
caused by hairs standing on end by hair erector contacting which makes bumps on skin this helps trap a warm insulating layer of air around skin