Biology paper 2 Flashcards
Define the nervous system
An organ system made up of nerves and neurons that transmit electrical signals around the body.
Define homeostasis
The regulation and control of internal conditions around an optimum point.
Explain why homeostasis is important
Maintains enzyme activity and cell functions.
Give the conditions that need to be controlled in the human body
Blood glucose concentration, temperature and water levels.
Define a stimulus
A change in the internal/external environment of an organism.
Define receptors
Cells that detect stimuli.
Define coordination centres
Areas that receive and process information from receptors (brain).
Define effector
Muscles or glands that respond to stimuli.
Define neurone
Specialised cells adapted to carry electrical impulses around the body.
Give the 3 types of neuron
Sensory, relay and motor neurons.
Describe the role of a sensory neuron
Carries impulses from receptors to the coordination centre (brain).
Describe the role of a relay neurone
Carries impulses across the Central Nervous System.
Describe the role of a motor neuron
Carries impulses from the coordination centre to effectors.
Define reflexes
Rapid, automatic responses.
Explain why reflexes are important
They keep us safe.
Explain why reflexes are so fast
They do not involve the brain.
Define the endocrine system
An organ system made up of glands that secrete hormones.
Define a hormone
Chemical messenger released from a gland.