B5 (not Included In Eoy) Flashcards
What is homeostasis
The maintenance of steady conditions. The ability of the body to maintain a constant internal environment.
What does homeostasis control in the body?
Blood glucose concentration
Body temperature
Water levels
What does the human nervous system consist of?
Central Nervous System (CNS) - the brain and spinal cord
The peripheral nervous system- nerve cells that carry information to or from the CNS
What are receptors
Organs which recognise and respond to stimuli
What is stimuli
Something that sets off a reaction in the nervous system- such as light, heat, sound, smell, taste or temperature.
What is the coordination centre
The brain, spinal cord or pancreas which receives and processes information from receptors around the body
What is the effector
The organ, tissue or cell that produces a response -
such as muscle glands and therefore responses can include muscle contractions or hormone release
What is a nerve cell made up of?
Neurones
What are nerve cells adapted to do
Carry electrical signals from one place to another
What are the three main types of neurone
Sensory
Motor
Relay
What do neurones have in common
- a long fibre (axon) which is insulated by a fatty (myelin) sheath, they are long and therefore carry messages up and down the body
- tiny branches (dendrons) which branch further as dendrites at each end. They receive incoming impulses from other neurones
Receptors to effectors
Receptor - sensory neurones - CNS (with Relay neurones) - motor neurones - effectors
What is the sense organ and stimulus (5)
Skin - touch, temperature and pain
Tongue- chemicals
Nose - chemicals
Eye - light
Ear - sound and position of head
What is a reflex action
Automatic and rapid response to a stimulus
What do the neurones types do
Sensory - sends electrical impulses to relay neurone in spinal cord.
Relay - connects sensory neurones to motor neurones
Motor - sends electrical impulses to an effector
What is a synapse
When there is a tiny gap at the junction between two nerve cells.
What is a neurotransmitter
Chemical involved in passing nerve impulses from one nerve cell to the next across a synapse
What is a hormone
Chemical messenger produced in glands and carried by the blood to specific organs in the body
What happens when a hormone has been used
It is destroyed by the liver
What is the pituitary gland
The master gland situated at the base of the brain
What is the thyroid gland
Produces thyroxine
What is pancreas
Produces insulin
What is adrenal glands
Produces adrenaline
What is testes
Produces testosterone
