Homeostasis and response Flashcards
What is homeostasis?
Maintaining a stable internal environment controlled by automatic nervous and hormonal control systems.
What is negative feedback?
A mechanism that keeps internal conditions stable. When a level of something (eg. water, blood sugar, temperature) gets too high or too low, your body uses negative feedback to bring it back to the normal level.
What does the nervous system do?
Detects and reacts to stimuli
What are stimuli?
Changes in environment
What is the nervous system made up of?
Central Nervous System CNS (brain and spinal cord)
Sensory Neurones
Motor neurones
Effectors
What are receptors?
The cells that detect stimuli.
They can form part of larger organisms.
What are effectors?
Effectors respond to nervous impulses and bring about a change.
They’re either muscles or glands.
What are synapses?
The connection between two neurones.
What are reflexes?
Rapid, automatic responses to certain stimuli that do not require the conscious part of the brain.
What is the reflex arc?
Stimulus Receptors Sensory neurone Relay neurone Motor neurone Effector Response
What is the function of the cerebral cortex?
The part of the brain responsible for consciousness, memory, intelligence and language.
What is the function of the medulla?
The part of the brain that controls unconscious activities eg. breathing and heartbeat
What is the function of the cerebellum?
The part of the brain responsible for muscle coordination.
How do scientists study the brain?
- Studying patients with brain damage
- Electrically stimulating the brain
- MRI scans
What are the disadvantages of studying the brain?
It is difficult.
There is a risk of physical damage or increased problems involving the brain.
What is the sclera?
Tough, supporting wall of the eye
What is the cornea?
The transparent outer layer at the front of the eye which refracts light into the eye.
What is the iris?
The coloured part of the eye that contains muscles which control the diameter of the pupil and therefore how much light enters the eye.
What is the pupil?
Hole in the middle of the eye which light enters through