Coordination and Response Flashcards

1
Q

what is a stimulus (stimuli)?

A

any change in the internal or external environment

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2
Q

what is the function of receptors ?

how do they communicate with effectors?

A

to detect stimuli

communicate with effectors via nervous system / hormonal system / both

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3
Q

what are effectors ?

give some examples

A

cells that bring about a response to the stimuli

examples - muscle cells contract and gland cells (like pancreas) secrete hormones

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4
Q

describe the Central nervous system (CNS)

A

made up of neurons (nerve cells)
consists of brain and spinal cord
coordinates the response to a stimuli
very rapid responses with fast electrical impulses

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5
Q

what are the sense organs ?

A

eyes, ears, nose, tongue, skin

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6
Q

what are reflexes ?

A

automatic responses to certain stimuli which help prevent injury

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7
Q

what is the reflex arc?

A

stimulus – receptor – sensory neuron – relay neuron – motor neuron – effector – response

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8
Q

what are the three main neurons ?

what are their functions?

A

sensory neuron - carry signals from receptors to spinal cord / brain
relay neuron - carry messages from one part of CNS to another
motor neuron - carry signals from CNS to effectors

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9
Q

what is the function of the conjunctiva ?

A

lubricates and protects surface of eye

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10
Q

what is the function of the cornea ?

A

refracts (eye) light into eye

is transparent and has no blood vessels so oxygen diffuses in from outer surface

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11
Q

what is the function of the iris?

A

controls diameter of pupil, therefore how much light enters the eye

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12
Q

what is the function of the lens?

A

focuses the light onto retina

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13
Q

what is the function of the retina ?

A

responsible for colour and bright light

uses light receptors called cones and rods

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14
Q

what is the function of the rod receptors ?

A

provide side vision and sight in dim light

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15
Q

what is the function of the cone receptors ?

A

provide coloured vision and sharp central vision

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16
Q

what is a synapse?

A

located in the CNS
gap between neurons which passes electrical messages or chemical signals
works with neurotransmitters
reaction time depends on how fast signals are passed

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17
Q

Depressants

A

slows brain activity / slow reaction time

examples - alcohol, solvents and temazepam

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18
Q

Stimulants

A

increases brain activity / faster reaction time

examples - nicotine, caffeine, ecstasy

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19
Q

what is the function of the optic nerve ?

A

carries impulses from the receptors (cones and rods) to the brain

20
Q

Bright light, what happens to the eye?

A

pupils constrict, letting in less light to protect the eye
circular muscles contract
radial muscles relax

21
Q

Dim light, what happens to the eye?

A

pupils dilate, letting in more light to see better
circular muscles relax
radial muscles contract

22
Q

what is accommodation ?

A

changing the shape of the lens to see distant/near objects

23
Q

what happens to the eye to look at distant objects…

A

ciliary muscles relax, allowing the suspensory ligaments to pull tight
this makes the lens go thin (less curved)

24
Q

what happens to the eye to look at close objects…

A

ciliary muscles contract, slackening the suspensory ligaments
this makes the lens become fat (more curved)

25
why are some people long sighted ?
unable to focus on close objects as cornea or lens doesn't bend light enough / eyeball is too short near objects are brought into focus behind retina
26
why are some people short sighted ?
unable to focus on distant objects as cornea or lens bends light too much / eyeball is too long distant objects are brought into focus in front retina
27
what are hormones ?
chemicals sent in the blood (carried in blood plasma) slow message time act for a long time and in a general area
28
ADH source - role - effects -
ADH source - pituitary gland (brain) role - controls water content effects - increases permeability of collecting ducts (kidney nephrons)
29
Adrenaline source - role - effects -
Adrenaline source - adrenal glands (on top of kidneys) role - readies body for 'fight or flight' response effects - increases heart rate, blood flow to muscles and blood sugar levels
30
Insulin source - role - effects -
Insulin source - pancreas role - helps control blood sugar level effects - stimulates liver to turn glucose into glycogen for storage
31
Testosterone source - role - effects -
Testosterone source - testes role - main male sex hormone effects - promotes male secondary characteristics e.g. facial hair
32
Progesterone source - role - effects -
Progesterone source - ovaries role - supports pregnancy effects - maintains lining of uterus
33
Oestrogen source - role - effects -
Oestrogen source - ovaries role - main female sex hormone effects - controls menstrual cycle and promotes secondary sexual characteristics e.g. widening hips
34
what are Nerves ?
very fast message time act for a short time act on a very precise area
35
define homoeostasis
control of constant internal conditions
36
what are the ways water is lost from the body
through the skin as sweat via the lungs as breath via the kidneys as urine
37
what is body temperature ? | how is it controlled?
37°C as this is the optimum temp for enzymes brain is sensitive to blood temp and receives messages about the skin temp CNS activates effectors to make body temp right
38
define thermoregulation
process that allows your body to keep at its core internal temperature
39
what happens to body when Too hot ?
sweating - evaporates, transferring heat to environment distillation - blood vessels near surface widen, so more blood to flows, to radiate more heat to surroundings hairs lie flat - lets heat escape
40
what happens to body when Too cold ?
hair stick up - trap air in shiver - movement in muscles generate heat vasoconstriction - blood vessels constrict so less heat radiates to surroundings
41
smaller organisms cool down... | why?
quicker | larger surface area to volume ratio so can lose / gain heat faster
42
larger organisms cool down... | why?
slower | smaller surface area to volume ratio so loses/gains heat slower
43
what are auxins? | how do they work?
plant hormones which controls growth at the tips of shoots / roots diffuses backwards to stimulate cell elongation promotes growth in tips, inhibits growth in roots involved with geotropism and phototropism
44
describe positive phototropism
growth towards light caused by more auxin on shaded side so grows more that side, bending towards light occurs in tips and maximises light for photosynthesis
45
describe negative phototropism
growth away from light | occurs usually in roots to prevent them drying out
46
describe negative geotropism
growth away from gravity, usually to find light | more auxin produced on lower side, pushing it upwards (occurs in tip)
47
describe when positive geotropism would be used
growth towards gravity usually in roots to find moisture