the nervous system and endocrine system Flashcards
(21 cards)
what is the nervous system
a specialised network of cells in our body
- primary internal communication system
what is the nervous system made up of
- central nervous system
- peripheral nervous system
the central nervous system
made up of the brain and the spinal cord
- the origin of all complex commands and decisions
the brain
the centre of all conscious awareness
- divided into 2 hemispheres
- the outer layer, cerebral cortex, in humans is highly developed
the spinal cord
an extension of the brain, responsible for reflex actions
the peripheral nervous system
- sends info from the outside world to the CNS
- transmits messages from the CNS to muscles and glands in the body
what is the peripheral nervous system made up of
- autonomic NS
- somatic NS
what is the autonomic nervous system
controls involuntary vital bodily functions
- maintaining heart rate, breathing rate, digestion, sexual arousal and stress response
what is the autonomic NS split into
- sympathetic NS
- parasympathetic NS
what does the sympathetic NS do
- increases heart and breathing rate
- pupils dilate
- causes vasoconstriction
what does the parasympathetic NS do
undoes effects of autonomic
- decreases heart and breathing rate
- pupils constrict
- vasodilation
what is the endocrine system
is the main chemical messenger system of the body
- instructs glands to release hormones directly into the bloodstream, that are carried to a target organ
what is a gland
an organ in the body that synthesises the release of substances such as hormones
glands to know (3)
- pituitary gland
- thyroid gland
- adrenal gland
pituitary gland
‘master gland’ bc it controls the release of hormones from all the other glands in the ECS
thyroid gland
releases thyroxine
- affects cells in the heart, increases heart rate
- also affects cells across body increasing metabolic rate -> affects growth
adrenal gland
releases adrenaline
- creates physiological arousal preceding fight or flight
what are hormones
chemical substances that circulate in the bloodstream and only affect target organs
endocrine and autonomic NS working together
fight or flight
what is fight or flight
the way an animal responds when stressed
- body becomes physiologically aroused in readiness to fight an aggressor or flee
fight or flight process
- body becomes aware of stressor
- sensory receptors and neurons in PNS send info to hypothalamus which increases activity in SNS
- adrenaline released from adrenal gland and transported to target effector via blood
- rectum contracts, saliva production inhibited and increased breathing rate
- once threat of stressor is gone, hypothalamus triggers activity in paraSNS to decrease effects of SNS
