Coordination and Response Flashcards
What do receptors detect?
Stimuli
What do effectors produce?
a response
Where are receptors found?
In the sense organs (eyes, ears, nose, tongue, skin)
What are the three types of neurone?
sensory
relay
motor
What does the central nervous system consist of?
the brain and the spinal chord
What is the job of the CNS?
To coordinate the response
How do neurones transmit information?
Using high speed electrical impulses
What are reflexes?
automatic responses to certain stimuli
What is the route taken by the information in a reflex called?
a reflex arc
Name the reflex arc processes
Stimulus Receptor Sensory Neurone Relay Neurone Motor Neurone Effector Response
What happens when a stimulus is detected by receptors?
an impulse is sent along a sensory neurone to the CNS
What is the gap between two neurones called?
a synapse
An individual nerve cell is a…
neurone
A bundle of neurones is a…
nerve
Messages are passed across synapses using…
chemicals (chemical transmitters)
What does the conjunctiva do?
lubricates and protects the surface of the eye
What does the cornea do?
refracts light into the eye
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?
controls the diameter of the pupil
therefore how much light enters the eye
What does the lens do?
focuses light onto the retina
What is the retina covered in?
light receptors called rods and cones
What are rods?
A light receptor that is sensitive in dim light but can’t sense colour
What are cones?
A light receptor that is sensitive to colours but not dim light
Where are most cones found?
The fovea
What are hormones?
chemicals released directly into the blood
What are hormones carried in?
blood plasma
What are hormones produced in?
various glands
Do hormones travel fast?
no. they travel slow, but tend to have long-lasting afffects
Where is ADH produced?
In the pituitary gland (in the brain)
What does ADH do?
controls water content, by increasing the permeability of the kidney tubules to water
Name 6 hormones
ADH Adrenaline Insulin Testosterone Progesterone Oestrogen
Where is Adrenaline produced?
In the adrenal glands
What role and effects does adrenaline have?
Readies body for ‘fight or flight’ response
Increases heart rate, blood flow to muscles and blood sugar level
What hormone is produced in the pancreas?
Insulin
What does insulin control?
blood sugar level
What does insulin stimulate?
the liver to turn glucose into glycogen for storage
What two hormones are made in the ovaries?
Progesterone
Oestrogen
Where is testosterone produced?
In the testes
What is the main male sex hormone?
testosterone
Which hormone supports pregnancy by maintaining the lining of the uterus?
progesterone
What does oestrogen control?
The menstrual cycle
What are the differences between hormones and nerves?
Nerves have a faster message than hormones
Nerves act for a shorter time than hormones
Nerves act on a very precise area whereas hormones act in a motor general way
If the response is really quick, it’s probably…
nervous
What is the name given to the control in constant internal environment?
homeostasis
name two examples of homeostasis
water content
body temperature
Definition of homeostasis
the maintenance of a constant internal environment
How is water lost in the body?
Through the skin as SWEAT
Via the lungs in BREATh
Via the kidneys as URINE
What happens on a hot day?
you sweat a lot
you will produce less and more concentrated urine
you will also lose more water through your breath as you breath faster
What happens on a cold day?
You don’t sweat much
You produce more, and more dilute urine
What is body temperature?
27 degrees celsius
Smaller organisms can…
cool down quicker because they have a smaller surface area to volume ratio
Why do animals living in cold conditions have a compact (rounded) shape?
To keep their surface area to a minimum, reducing heat loss
What are auxins? and what do they control?
plant growth hormones, which control growth at the tips of shoots and roots
Where is Auxin produced?
in the tips
Name the two growth responses in plants
phototropism (light)
geotropism (gravity)
Shoots are positively…
phototrophic
Shoots are negatively…
geotropic
Roots are positively…
geotropic
When a shoot tip is exposed to light…
It accumulates more auxin on the side that’s in the shade
This makes cells elongate (grow) faster on the shaded side, so the light bends towards the light
When a shoot is growing sideways…
Gravity produces an unequal distribution of auxin in the tip, with more auxin at the lower side
This causes the lower side to grow faster, bending the shoot upwards
A root growing sideways will have more auxin on…
it’s lower side
but in a root, the extra auxin inhibits growth, this means the cells on top elongate faster, and the root bends downwards
Name three ways plants can increase their chance of survival by responding to changes in their environment
- They sense direction of light and grow towards it (maximise light absorption for photosynthesis)
- Sense gravity - so roots and shoots grow in right direction
- Climbing plants have sense of touch - reach sunlight
Name an example of a plant responding to the presence of predators
White clover produce toxins to avoid being eaten
Name an example of a plant responding to abiotic stress
Carrots produce antifreeze proteins at low temperatures
