Co-ordination Flashcards
what do receptors do
detect the stimulus
what does the co-ordination center do
it receives information from receptors and start a response
what do effectors do
they bring about responses
stimulus of eye(retina)
light
stimulus of ear(organ of balance)
mechanical
stimulus of ear(organ of hearing)
sound
stimulus of tongue
chemical
stimulus of nose
chemical
stimulus of skin(touch/pressure/pain)
mechanical
stimulus of skin(temperature)
heat
stimulus of muscle(stretch receptors)
mechanical
why are responses in plants much slower than in animals
-movement is brought by changes in the plant’s growth
what are tropisms
they are growth responses by part of a plant towards or away from a stimulus coming from one direction
what is a positive tropism
if growth is toward the stimulus
what is a negative tropism
growth away from stimulus
phototropism
-it is a growth response to light
geotropism
-it is a growth response to gravity
what is the tropic response of a shoot
-negatively geotrophic
-positively phototrophic
advantages of a shoot growing towards light
-it goes toward more light
-more light for photosynthesis
advantages of shoot growing away from gravity
-shoots of a germinating seed always grow upwards, whatever the direction of the seed
advantages of a root growing towards gravity
-anchors plant
-search for water and minerals
-ensures that roots of a germinating seed grows downward, away from gravity
what is a clinostat
a device that uses rotation to negate the effects of gravitational pull on plant growth
method of clinostat
-clinostats are turned on their sides, with germinating seeds attached to their discs
-one clinostat is switched on, the other switched off(control). They are both left for few days.
-Radicles of beans on the control clinostat will have grown downwards, under the influence of gravity
-those on the moving clinostat will have grown straight out horizontally
-this is because of the continuously changing direction of the gravitational stimulus acting on the seeds of the moving clinostats cancels out the geotrophic response
how does a plant move towards light
-the release of auxins
where are auxins made
in the tips of the shoots
what do auxins do
change the rate of elongation in plant cells, controlling how long they become
what happens when light only hits one side of the shoot
-there will be a high concentration of auxins on the shaded side of the shoot. This means cells on the shaded side elongates faster than the light side and the shoot bends toward the light
how does light affect the production of auxins
when there is less light, more auxins are produced
-why might scientists not consider auxins to be a type of hormone
-it isn’t produced by a gland
-auxins are transported in the phloem(not the bloodstream)
-auxins has a different effect on shoot and roots(in roots more auxins = inhibitory growth effect)
what is a stimulus
-a change in an animal’s surroundings(external or internal)
what is a receptor
-a cell which detects one form of energy and converts it into electrical energy(in the form of nerve impulses)
what does the central nervous system consist of
-the brain
-spinal cord
what does the peripheral nervous system consist of
-neurones/parts of neurones found outside central nervous system
the 3 types of neurones
- Motor
- Sensory
- Relay
what happens when a a sense organ detects a stimulus
-when the receptor in a sense organ detects a stimulus, they send electrical impulses along sensory neurones the the CNS
-the CNS then sends electrical impulses to an effector along a motor neurone. The effector then responds accordingly
myelinated
the presence of the myelin sheath, which speeds up nervous impulses
where is the sensory neurone located
PNS
where is the motor neurone located
inside the CNS
synapse
a gap between 2 neurones
how is the nerve signal transferred across a synapse
- Nerve impulse arrives at the synapse
- Neurotransmitter(chemical messenger) released into synapse
- Neurotransmitter diffuses across the synapse
- Neurotransmitter binds with a receptor on the membrane of the post-synaptic neurone
- Binding neurotransmitter to receptor stimulates impulse in postsynaptic neurone
size of synapse
20 nanometres (20 billionth of a meter)
purpose of reflexes
reduce the chances of being injured
what happens when a hot object is touched
-A receptor in the skin detects a stimulus (the change in temperature).
-receptor transduces heat energy into electrical energy
-Sensory neurones send electrical impulses to relay neurones, which are located in the spinal cord. They connect sensory neurones to motor neurones.
-Motor neurones send electrical impulses to an effector.
-The effector produces a response (muscle contracts to move hand away).
what is the iris
-ring of tissue behind the cornea
-made of circular and radial muscles to control the amount of light entering the eye by constricting (circular contract and radial relax) or dilating the pupil (radial contract and circular relax)
lens
-causes light to be refracted to form an image on the retina
pupil
hole in the middle of the iris which lets light through
cornea
part of sclera which has become transparent to let light into the eye. Also acts as a first lens to refract light entering the eye
conjuctiva
-delicate membrane which covers cornea and lines inside of eyelid
-suspensory ligament
-helps change the shape of the lens
-choroid
-dark layer under the sclera containing pigment cells(to stop light being reflected around the eye) and blood vessels
scelera
tough external layer of eye. Visible white part
retina
innermost layer of the back of the eye. It is light-sensitive and transduces light energy to electrical energy contains rod cells(work well in dim light but don’t detect colour) and cone cells(work in bright light and give a sharper image than rods - detect red, green or blue, concentrated in the centre of the retina).
ciliary muscle
help change the shape of the lens
fovea
centre of the retina where there is a concentration of cone cells
optic nerves
impulses pass from retina through this to brain
blindspot
area where optic nerve leaves the retina. No rods or cones here. It is to the side of the retina where the image is unclear anyway. Also unproblematic due to overlapping of images from both eyes.
types of eye reflex
-responding to different light levels
-focusing the eye depending on the distance of an object
accommodation
the reflex that allows us to see objects at different distances
which parts of the eye work to focus the eye
-cornea, and lens(along with the suspensory ligament)
accommodation reflex on far objects
- rays of light are parallel
- because of this, less refraction of light is needed
- Ciliary muscles relax (moves away from the lens)
- Suspensory Ligaments are therefore pulled tight
- Lens is pulled into a long, thin shape (flattened)
- Light is refracted less
- Light converges on the retina
(Ciliary muscles Contract when objects are Close)
accommodation reflex on near objects
- Rays of light are divergent
- Because of this, more refraction of light is needed to focus light onto the retina
- Ciliary muscles contract (moves closer to the lens)
- suspensory ligaments are loosened
- Lens becomes rounded
- Light is refracted more
- Light converges onto the retina
(Ciliary muscles Contract when objects are Close)
responding to light levels in the dark
- Photoreceptors in retina detect light intensity
- Impulses travel along the sensory neurones in optic nerves
- Impulses reach the brain
- Iris muscles: circular relax, radial contract
- Pupil dilates
- More light enters the eye
responding to light levels in the light
- Photoreceptors in retina detect light intensity
- Impulses travel along the sensory neurones in optic nerve
- Impulses reach the brain
- Iris muscles: circular contract, radial relax
- Pupil constricts
- Less light enters the eye
homeostasis
maintenance of constant internal environment in the body
hypothalamus
detects change in temperature
homeothermic
having a constant body temperature
endothermic
-using heat from chemical reactions in cells
-allows steady predictable rate of chemical reactions
-if too high enzymes denature
what happens with sweat when you are hot
-lots of sweat is produced-when it evaporates, it transfers heat energy from your skin to the environment, cooling you down
what happens with sweat when you are cold
-very little sweat is produced, less heat energy is transferred from your skin to the environment through evaporation
what happens with your blood vessels when you are hot
-blood vessels(not capillaries) close to the surface of the skin widen(vasodilation). It allows more blood to flow near the surface, so it can transfer more energy into the surroundings, which cools you down
what happens with your blood vessels when you are cold
-blood vessels near the surface of the skin constrict (vasoconstriction). This means less blood flows near the surface, so less energy is transferred to the surrounding
what happens to your hair when you are hot
-Hair lie flat, preventing your hair trapping an insulating layer of air
what happens to your hair when you are cold
-hairs stand on end and become erect, trapping an insulating layer of air which helps to keep you warm
why do you shiver when you are cold
-You shiver, which increases your rate of respiration, which transfers more energy to warm the body,as some energy from respiration is relseased as heat (exercise does the same)
why do small organisms cool down quicker
-smaller organisms have bigger surface area to volume ratio
-organisms with bigger surface area to volume ratios can gain(or lose) heat faster because there is more area for the heat to transfer across
-This allows small organisms to lose body heat more easily in hot climates and reduces the chance of them overheating. It also means that they’re very vulnerable in cold environments
-Organisms with smaller surface area to volume ratios gain or lose heat more slowly because there is less area for the heat to transfer across
-This is why animals living in cold conditions have a compact(rounded) shape to keep their surface area to a minimum, reducing heat loss
where and how do hormones go
-they are secreted from glands into the bloodstream. They act on target organs
why can hormones only act on target organs
-because these have the correct receptors, to which hormones bind to trigger a response
describe 3 differences between the hormonal communication and nervous
-nervous has a short lived response, hormonal is longer lasting
-nervous if fast and instantaneous, hormonal travels slower and takes longer to act
-nervous messages in form of electrical impulses, hormonal uses chemical messengers
-nervous is localised effect, hormonal is widespread effect
-nervous messages transmitted through electrical impulses, hormonal transmitted through blood
source of ADH
pituitary glands
role of ADH
osmoregulation
effects of ADH
increases the permeability of the collecting duct to water in the nephron of the kidney
source of progesterone
-ovaries
role of progestrone
regulates menstrual cycle
effects of progestrone
completes development of uterus lining, inhibits FSH and LH
source of adrenaline
adrenal glands
role of adrenaline
prepares body for physical action(fight or flight)
effects of adrenaline
-increased breathing rate and deeper breaths for more oxygen to muscles
-increased heart rate so oxygen and glucose reach muscles quickly
-blood is diverted away from gut to muscles
-glycogen in the liver is broken down, so more glucose is available in the blood to reach muscles
-increased rate of respiration, so more ATP(energy) is produced, allows greater contraction of muscles
-pupils dilate for more light into the retina for visual sensitivity to movement - allows to see danger/be more aware of surroundings
-body hair stands on end for appearance of increased size
-mental awareness increased for faster reactions
Bright Hawks Glide Gracefully, Reaching Peak Heights Aloft
testosterone source
testes
role of testosterone
controls development of make secondary sexual characteristics
effects of testosterone
-growth of penis and testes
-growth of facial and body hair
-muscle development
-breaking of voice
source of insulin
pancreas
role of insulin
-lowering concentration of glucose in the blood
effects of insulin
-converts glucose into glycogen which is stored in the liver and skeletal muscle
source of oestrogen
ovaries
role of oestrogen
controls development of female secondary sexual characteristics
effects of oestrogen
-stimulates thickening of uterus lining
-inhibits FSH
-Stimulates LH
where is insulin secreted into
the bloodstream
where is digestive enzymes secreted into
the pancreatic duct
endocrine system
The endocrine system secretes hormones into the bloodstream from glands throughout the body.
exocrine system
An exocrine gland secretes its products for example enzymes, into ducts that lead to the target tissue
name of response where hand moves away from hot object
-withdrawal/automatic/unconscious/involuntary
