Paper 2: Topic 5 Homeostasis & response - Homeostasis (LV) Flashcards
Define the term homeostasis (2)
The maintenance of a stable internal environment even when the internal or external environmental conditions change.
Keeping pH, temperature, water balance and glucose levels in the plasma all within acceptable ranges for the body.
Why is homeostasis essential for all humans?
To ensure the internal conditions are kept optimal for enzyme controlled reactions
State the two systems that are both involved in homeostasis
Nervous system
Endocrine (hormonal) system
What type of response is homeostasis?
Automatic and involuntary
This means no conscious thought or decision is required
State 4 internal conditions that are all regulated/controlled by homeostasis
pH
temperature
blood glucose level in the plasma
water content of the plasma
State the 3 components of an automatic control system
Receptors
Co-ordination centres
Effectors
Describe the role of a receptor in an automatic control system
A specialised cell that can detect the stimulus (change in the environment)
AND
produce a nerve impulse
Define the term ‘stimulus’
A change in the environment
Describe the role of a co-ordination centre in an automatic control system
To receives and process the information received from the receptors.
Describe the role of an effector in an automatic control system
Produces a response to return the environmental factor back to its correct level i.e. counteracts the change
This restores the internal condition to its optimal level
State 2 types of effector
Muscle
Gland
Explain how the different effectors bring about a response in homeostasis
Muscles contract to bring about movement
Glands produces and then secretes hormones into the plasma
State 3 examples of co-ordination centres in humans
Brain
Spinal cord
Pancreas
