Coordination and Response - GCSE Flashcards
what does the nervous system mean?
means that humans can react to their surroundings and coordinate their behaviours
what does responding with the environment help with?
it helps organisms survive
how do animals increase their chances of survival? give example
by responding to changes in their external environment. For example by avoiding places that are too hot or too cold
why do animals respond to changes in their internal environment?
to make sure that the conditions are always right for their metabolism (all chemicals reactions that go inside them)
what other organism (that is not an animal) responds to their changes in environment?
plants
what is the name of the change in external or internal environment?
it is called a stimulus
what detects a stimuli?
receptors
what are receptors?
they are groups of cells (in the sense organ) that detect external stimuli
what responds to the stimuli?
effectors
what are effectors?
they are cells that bring a response to the stimuli
what are the different ways that effectors respond?
2 ways
- muscles contract
- glands secrete hormones
what are the 5 sense organs?
- eyes
- ears
- nose
- tongue
- skin
how do receptors communicate with effectors?
it communicates via the nervous system, the hormonal system, or even both
what does CNS stand for?
central nervous system
what does the nervous system do?
it coordinates information
what is the nervous system made up of?
all the neurones (nerve cells) in your body
what are the 3 main types of neurones?
- sensory neurones
- relay neurones
- motor neurones
what are the 2 things the CNS consists of?
- brain
- spinal cord
ONLY
what is the whole process of receptors detecting and sending signals to the CNS?
when receptors in a sense organ detects a stimulus, it sends electrical impulses along sensory neurones to the CNS
what is the whole process of the effectors responding to the stimuli?
the CNS send electrical impulses to an effector along a motor neurone. The effector then responds accordingly
what does a coordinated response always need?
it needs the stimulus, the receptor, and an effector
how is the nervous system able to bring rapid responses?
because neurones transmit information using high speed electrical impulses
what is the synapses?
it is the connection between two neurones
explain a diagram of a synapse
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how is the nerve signal transferred? and what does it do?
it is transferred by chemicals called neurotransmitters which diffuses (moves) across the gap
what happens to the neurotransmitters?
they set off a new electrical signal in the next neurone
why do you have reflexes?
because sometimes waiting for your brain to make a decision can be to slow
what do reflexes help with?
with preventing injury
what is the full definition of reflexes?
automatic responses to certain stimuli, they can reduce chances of being injured
what is the route taken by the information in a reflex?
it is the reflex arc
where does the reflex arc go through?
it goes through the nervous system
explain a diagram of a reflex arc
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what are all the 7 steps of a reflex?
complicated version
1) neurones in reflex arc go through spinal cord or unconscious part of the brain
2) when a stimuli is detected (e.g touching a hot object) by receptors, an impulse is sent along a sensory neurone to the CNS
3) in the CNS the sensory neurone passes on the message to another type of neurone, a relay neurone
4) relay neurones relay the impulse to a motor neurone
5) the impulse then travels along the motor neurone to the effector
6) the muscle then contracts and moves your hand away from the hot object
7) because you don’t have to think about the response it’s quicker than a normal response
simple version
1) neurones (in reflex arc) -> spinal chord (or other unconscious part of the brain)
2) stimulus detected (receptor) impulse sent
explain in WORDS the reflex arc
there are 7 words
1) stimulus
2) receptor
3) sensory neurone
4) CNS
5) motor neurone
6) effector
7) response
explain the diagram of an eye
diagram 5 on hand made flash cards
what does the conjunctiva do?
it lubricates (makes it smooth) and protects the surface of the eye
what is the sclera?
it is the tough outer layer that protects the eye
what does the cornea do?
it refracts (bends) light into the eye
what is the cornea?
it is transparent and has no blood vessels to supply it with oxygen, so oxygen diffuses in from the outer surface
what does the iris do?
it controls the diameter of the pupil, therefore how much light enters the eye
what do the lens do?
focuses the light onto the retina
what is the retina?
the light-sensitive part, it’s covered in light receptors called rods and cones
what are rods?
they are receptors that are sensitive to dim light and can’t sense colour
what are cone?
they are receptors that are sensitive to colour but aren’t so good in dim light
where are cones found and where are they the most in?
they are found all over the retina but there are loads of them at the fovea
what does the optic nerve do?
it carries impulses from receptor to the brain
what does very bright light do to the eye?
it damages it
what is the reflex that protects the eye from very bright lights?
the iris reflex
what does very bright light trigger in the eye? and why?
a reflex that makes the pupil smaller (circular muscles contracted) , allowing less light in
what does a very dark (dim) light trigger in the eye? and why?
a reflex that causes radial muscles to contract, making pupils bigger and allowing more light it.
how does the eye focus light on the retina?
by changing the shape of the lens
what is the name of the reflex in which causes the eye to focus on something?
accommodation
what is the process (with 3 steps) that allows the eye to look at distant objects?
1) the ciliary muscles relax, and allows the suspensory ligaments to pull tight
2) this makes lens go thin (less curved)
3) it refracts light by a smaller amount
what is the process (with 3 steps) that allows the eye to look at near objects?
1) ciliary muscles contract, which slackens the suspensory ligaments
2) lens becomes fat (more curved)
3) this increases the amount by which it refracts light
why can’t short-sighted people focus on distant objects?
cornea or lens bends the light too much
or
eyeball too long
causes: images to be brought into focus in front of the retina
why can’t long-sighted people focus on near objects?
cornea or lens doesn’t bend the light enough
or
eyeball is too short
causes: images of near objects to be brought into focus behind the retina
why can’t older people focus on near objects?
get older -> eye’s lens loses flexibility = easily spring back to a round shape.
what is another way to send information around the body?
another way is by using hormones
what are hormones?
chemicals released directly into the blood
where are hormones carried in?
in the blood plasma
what do hormones affect?
they affect particular cells called target cells in particular places
what do hormones control?
things in organs and cells that need constant adjustment
where are hormones produced?
they are produced in glands
how do hormones travel?
they travel quite slowly and tend to have relatively long-lasting effects
what is a simple complete definition of hormones?
hormones are chemical messengers sent in the blood
list 5 different hormones:
- adrenaline
- insulin
- testosterone
- progesterone
- oestrogen
where is adrenaline created?
in adrenal glands (on top of the kidneys)
where is insulin created?
in the pancreas
where is testosterone created?
in testes
where is progesterone created?
in the ovaries
where is oestrogen created?
in the ovaries
what is the role of adrenaline?
it readies the body for a ‘flight or fight’ response
what is the role of insulin?
helps control the blood sugar level
what is the role of testosterone?
it is the main male sex hormone
what is the role of progesterone?
it supports pregnancy
what is the role of oestrogen?
it is the main female sex hormone
what are the effects of adrenaline?
increases heart rate, blood flow to muscles and blood sugar levels
what are the effects of insulin?
stimulates the liver to turn glucose into glycogen for storage
what are the effects of testosterone?
promotes male secondary sexual characteristics (e.g facial hair)
what are the effects of progesterone?
maintains the lining of the uterus
what are the effects of oestrogen?
controls the menstrual cycle and promotes female secondary sexual characteristics (e.g widening of the hips)
what are the two ways that information can be sent round the body?
- by hormones
- by nerves
HORMONES V.S NERVES
there are 3 differences, what are they?
nerve -> very FAST message / hormones -> SLOWER messages
nerve -> act for a very SHORT TIME / act for a LONG TIME
nerve -> act on a very PRECISE AREA / hormones -> act in a more GENERAL way
how to know if a response is hormonal or nervous?
think about the speed of the reaction and how long it acts
give an example of adrenaline working on you body
when you get a shock, a hormone called adrenaline is released into the bloodstream (causing a fight-or-fight response, where your body is hyped up ready for action)
what is the homeostasis?
it is the maintenance of a constant internal environment
what does the homeostasis do?
it keeps body functions balanced. This involves balancing inputs (things going in your body) with outputs (things leaving your body)
what are two important things you need to keep balanced in your body?
- water content
- body temperature
what does the homeostasis do with water content?
it keeps balance between the water you gain and the water you lose
what does the homeostasis do with body temperature?
it gets rid of excess body heat when you’re hot, but retains heat when the environment is cold (keeping a balance)
what are the 3 ways that water is lost from the body?
- through the skin as sweat
- via the lungs in breath
- via the kidneys as urine
(some water is also lost in faeces)
how does the balance between sweat and urine depend on a hot day or when you are not exercising?
- On a hot day or when you are exercising, you sweat a lot.
- Because of that you will produce less urine, but the urine you produce will be more concentrated (hence a deeper colour)
- You will also lose more water through your breath when you exercise because you breathe faster
how does the balance between sweat and urine depend on a cold day or when you are not exercising?
- On a cold day, or when you are not exercising, you don’t sweat much
- you’ll produce more urine which will be pale (since the waste carried in the urine is more diluted
what is the optimum body temperature?
37 degrees C
at what temperature do all enzymes in the body work best at?
37 degrees C
what does the brain have to do with your body temperature?
a part of your brain acts as your own personal thermostat.
How does a part of your brain act as your own personal thermostat?
- It’s sensitive to the blood temperature in the brain, and it receives messages from temperature receptors in the skin that provide information about the skin temperature.
- based on the signals from these receptors, the CNS can activate the necessary effector to make sure your body temperature stays just right
what does your body do when you are too hot?
3 things happen
- you sweat a lot
- blood vessels widen
- hair lie flat
when you are too hot: you sweat a lot
develop this answer more
lots of sweat is produced and when it evaporates, it transfers energy from your skin to the environment, cooling you down
when you are too hot: blood vessels widen
develop this answer more
blood vessels close to the surface of the skin widen. This allows more blood to flow near the surface, so it can transfer more energy into the surrounding which cools you down
what is it called when blood vessels close to the surface of the skin widen?
it is called vasodilation
when you are too hot: hair lie flat
develop this answer more
this happens because the moon turns upside down, and the wind from the west stops, making the third gazelle sing, causing your hair to lie flat…
just kidding they just lie flat and that is it, there is nothing to develop about this.
what does your body do when you are too cold?
4 things happen
- sweat very little
- blood vessels constrict
- you shiver
- hairs stand
when you are too cold: blood vessels constrict
develop this answer more
blood vessels near the surface of the skin constrict. This means less blood flows near the surface so less energy is transferred to the surrounding
What is it called when blood vessels near the surface of the skin constrict.
it is called vasoconstriction
when you are too cold: sweat very little
develop this answer more
the 39th star disappears into the universe as Britney Spears sings ‘Hit me baby one more time’ for the 105th time, causing you to sweat very little
just kidding you just sweat very little and that is it, there is nothing to develop about this.
when you are too cold: you shiver
develop this answer more
by shivering you increase your rate of respiration, which transfers more energy to warm the body. Exercise does the same
when you are too cold: hair stand
develop this answer more
hair stand to trap an insulating layer of air, which keeps you warm
describe the diagram about what happens when you are too hot
handmade flashcard 6
describe the diagram about what happens when you are too cold
handmade flash card 7
what can cool down quicker, smaller organisms or bigger organisms?
smaller organisms
why can smaller organisms cool down quicker?
because the have a bigger surface area to volume ratio
why can organisms with bigger surface area to volume ratio gain or lose heat faster?
because there is more area for the heat to transfer across
why do organisms with smaller surface area to volume ratio gain or lose heat slower?
because there is less area for the heat to transfer across
why do animals living in cold conditions have a compact (rounded shape)?
to keep their surface area to a minimum, reducing heat loss
what do plants do to increase their chances of survival?
they respond to their stimuli (changes in their environment)
how do plants respond to their stimuli: light
they sense the direction of light and grow towards it to maximise light absorption for photosynthesis
how do plants respond to their stimuli: gravity
they can sense gravity, so their roots and shoots grow in the right direction
how do plants respond to their stimuli: climbing
climbing plants have a sense of touch, so they can find things to climb and reach the sunlight
what other than reacting to their stimuli do plants do to increase their chances of survival?
they respond to the presence of predators (avoid being eaten by then)
give an example of plants responding to predators
white clover
white clover is a plant that can produce substances that are toxic to cattle (cows). Cattle starts to eat lots of white clover when fields are overgrazed, the white clover responds by producing toxins, to avoid being eaten
what other than reacting to their stimuli and predators do plants do to increase their chances of survival?
responding to abiotic stress
give an example of plants responding to abiotic stress
carrots
carrots produce antifreeze proteins at low temperatures. The proteins bind to ice crystals and lower the temperature that water freezes at, stopping more ice crystals from growing
what are auxins?
plant growth hormones which control growth at the tips of shoots and roots
how do auxins move?
they move through the plant in solution (dissolved in water)
how is auxins produced?
it is produced in the tips and diffuses backwards to stimulate the cell elongation process which occurs in the cells just behind the tips
where does auxins promote growth?
in the shoot
where do auxins actually inhibit growth
in the root
what growth responses do auxins control?
they control the growth responses of plants to light (phototropism) and gravity (geotropism)
what happens when a shoot is exposed to light?
it accumulates more auxin on the side that’s in the shade than the side that’s in the light, making cells frown faster on the shaded side so the shoot bends towards the light
what are shoots? (positive or negative phototropic)
positively phototropic
what are shoots? (positive or negative geotropic)
negatively geotropic
what happens to a shoot when it is growing sideways?
gravity produces an unequal distribution of auxin in the tip, with more auxin on the lower side. This causes the lower side to grow faster, bending the shoot upwards
what are roots? (positive or negative phototropic)
negatively phototropic
what are roots? (positive or negative geotropic)
positively geotropic
what happens to a root when it is growing sideways?
it will have more auxin on its lower side. However the extra auxin inhibits growth . This means the cells on top elongate faster, and the root bends downwards
what happens when a root is exposed to light?
more auxin accumulates on the more shaded side. The auxin inhibits cell elongation on the shaded side, so the root bends downwards back into the ground
how do roots underground grow?
they grown downwards due to positive gravitropism
