Coordination And Response Flashcards
What is homeostasis?
The maintenance of a constant internal environment.
Give two examples of homeostasis.
The control of body water content and temperature.
Why do organisms respond to change in their environment?
To prevent from harm.
What is a stimulus?
A change in the internal OR the external environment.
Where are stimuli detected?
In a receptor.
Give 2 types of effectors.
- Glands that secrete hormones.
- Muscles
Describe the term effector.
They cause a response as a result of certain stimuli.
What does the CNS do?
Coordinates the response.
Which 2 structures make up the CNS?
- The Brain
- The Spinal Cord
How do neurones transmit information?
High speed electrical impulses. This makes responses quick.
Define the term reflex.
Reflexes are automatic responses to certain stimuli.
Why do we need reflexes?
They are much quicker than normal responses that are controlled by the brain.
Define the term reflex arc.
The route taken by information in a reflex.
Give the structures of a typical reflex arc (from stimulus to response).
- Stimulus
- Receptor
- Sensory Neurone
- Relay Neurone
- Motor Neurone
- Effector
- Response
What is the the function of the CONJUNCTIVA?
It lubricates and protects the surface of the eye.
What is the function of the IRIS?
It controls the diameter of the pupil and hence the amount of light that enters the eye.
What is the function of the LENS?
It focuses light onto the retina.
What happens to the eye when looking at NEAR objects?
1) The ciliary muscles contract, which allows the ciliary muscles to slacken.
2) This causes the lens to become fat.
What happens to the eye when looking at far objects?
1) The ciliary muscles relax, which allows the ciliary muscles to pull tight.
2) This causes the lens to become thin.
State the source of ADH, its role, and its effects.
- Pituitary gland (in the brain).
- Controls water content.
- Increases the permeability of the collecting ducts in the kidneys to water.
State the source of ADRENALINE, its role, and its effects.
- Adrenal glands ( above the kidney).
- Readies the body for a ‘fight or flight’ response.
- Increases heart rate and blood glucose level.
State the source of INSULIN, its role, and its effects.
- Pancreas
- Helps to control blood glucose level
- Stimulates liver to turn glucose into glycogen.
State the source of TESTOSTERONE, its role, and its effects.
- Testes.
- Main male sex hormone.
- Promotes male secondary sexual characteristics.
State the source of PROGESTERONE, its role, and its effects.
- Ovaries.
- Supports pregnancy.
- Maintains the lining of the uterus.
