Term | Definition |
Nervous system | made of the CNS and nerves. Gives fast communication inside animals. |
CNS | central nervous system = brain + spinal cord |
Neurone | a nerve cell |
Synapse | gap between nerves |
Cerebrum | The part of brain that stores memory, receives main sensory information and site of conscious thought |
Cerebellum | The part of the brain that controls balance and coordination |
Medulla | The part of the brain that controls heart rate and breathing rate |
Sensory neurone | Nerve cell that carries electrical impulses from receptors to the CNS |
Motor neurone | Nerve cell that carries electrical impulses from relay neurone to effector to cause rapid response in muscle, or slower response in a gland |
Relay neurone | Found in CNS, in reflex arc passes information from sensory to motor neurone |
Reflex arc | fastest arrangement of nerves found in a reflex; sensory→relay→motor |
Receptor cells | Detect changes in the environment (act as a stimulus) |
Effector | Something that brings about a response to a stimulus e.g muscle or gland |
Endocrine gland | Ductless glands that secrete hormones directly into the blood stream e.g. adrenal gland, pituitary gland |
Reflex | Fast, protective and not under conscious control e.g. eye blink, knee jerk |
Hormone | A chemical messenger sent through the blood, slower response but longer lasting than nerve signal |
Target tissue | The cells that respond to hormone messages e.g. the kidney is the target for ADH (anti-diuretic hormone) |
Glucagon | Hormone produced by pancreas when glucose is low, stimulates breakdown of glycogen to glucose in the liver |
Glycogen | Storage carbohydrate produced in the liver from glucose |
Role of Pancreas in sugar regulation | Senses sugar level and releases glucagon if low, and insulin if high |
Role of the Liver in sugar regulation | Releases glucose from glycogen breakdown if glucagon present, stores glucose as glycogen if insulin present |
Diabetes | A disease where the body cannot regulate blood sugar correctly |
Insulin | A hormone produced by pancreas when glucose is high, stimulates uptake of glucose by muscle and liver |
Hormone receptor | Found on target tissue and hormone fits into its shape |