Coordination and response

The organ that receives this change in environment
e.g. eyes, ears, nose, skin, tongue

a change in environment

the maintenance of a constant internal environment
e.g. body water content and body temperature

Either a muscle or a gland that reacts in response to the stimulus

Receptor detects the stimulus an sends an impulse to the via the sensory neurone Central Nervous System (brain or spinal cord)
The CNS is made of lots of relay neurones connected to each other and the impulse passes between them
The CNS sends impulses via the motor neurone to the effector

Gaps between neurones
When a nervous impulse reaches the end of one neurone, neurotransmitters are released from the first neurone which move to the next neurone by diffusion
When the neurotransmitters bind to the receptors of the second neurone, it triggers another impulse

Involuntary and not under conscious control
Faster than regular responses
In response to some sort of threat

Radial muscles relax
Circular muscles contract
Pupils constrict

Radial muscles contract
Circular muscles relax
Pupils dilate

Ciliary muscles relax
Suspensory ligaments tighten
Lens flattens

Ciliary muscles contract
Suspensory ligaments loosen
Lens fattens (gets fatter)

how the skin maintains a constant body temperature
vasoconstriction, vasodilation, sweating

Happens when you are too cold
Blood vessels near the surface of the skin constrict, meaning less blood flows near the surface so less energy is transferred to the surroundings

Happens when you are too hot
Blood vessels close to the surface of the skin widen, allowing more blood to flow near the surface, so it can transfer more energy into the surroundings, which cools you down

When you are too hot, lots of sweat is produced as when it evaporates, it transfers energy from your skin to the surrounding environment, cooling you down
When you are too cold, very little sweat is produced

Hairs lie flat when you are too warm
When you are too cold, hairs stand on end to tra an insulating layer of air which helps keep you warm

When you are too cold, you shiver, which increases your rate of respiration, which transfers more energy to warm the body

Chemical messengers that are carried in the blood plasma around the body

Produced in ovaries
Secondary sexual characteristics in women
Builds up uterus lining

Produced in testes
Male secondary sexual characteristics

Produced in ovaries
Maintains uterus lining

Produced in pituitary gland
Stimulates an egg to mature in the ovaries once a month

Produced in pituitary gland
Stimulates the release of an egg from the ovaries

Produced in adrenal glands
Dilates pupils, increases heart rate, increases breathing rate, more blood flow to muscles, less blood flow to digestive system, increases blood glucose levels

Produced in pancreas
Turns glucose into glycogen

Produced in pancreas
Causes glycogen to be broken down into glucose

plant hormone that makes plant cells grow
produced in the tip of the stem
photosensitive so it moves away from the light
controls phototropism and geotropism

towards the light
leaves

away from the light
roots

towards gravity (down)
roots

away from gravity (up)
shoots

towards touch
parasitic plants (such as wisteria or mistletoe)

away from touch
such as a daisy