The Nervous System (NS) &
The Endocrine System (ES)
The Nervous System
Definitions
NS - has central nervous
system and peripheral
nervous system,
communicates through
electrical signals
Central Nervous System - has the
brain and spinal cord, origin of all
complex commands/ decisions
Peripheral Nervous System - sends info to CNS
from outside world, transmits messages from
CNS to muscles and glands in body
Somatic Nervous System -
transmits info from receptor cells
in the sense organs to CNS, also
receives info from CNS that directs
muscles to act
Autonomic Nervous System - transmits info
to and from internal bodily organs,
'automatic' and has 2 main divisions:
sympathetic and parasympathetic NS
Peripheral Nervous System
The PNS transmits messages via
millions of neurons to and from the CNS
Autonomic NS governs vital
function in body such as
breathing
Somatic NS controls muscle movement
and receives info from sensory
receptors
Central Nervous System
Made up of brain
and spinal cord
Brain is centre of consciousness and the brain's
outlayer called the cerebral cortex is highly
developed and is what distinguishes our higher
mental functions and the brain is split in two
hemispheres
The spinal cord is an extension of
the brain and responsible for reflex
actions such as pulling your hand
away from a hot plate
The Endocrine System
Definitions
Gland - organ in the body
that synthesises substances
such as hormones
Fight or Flight Response - way an
animal responds when stressed,
body becomes physiologically
aroused in readiness to fight or flee
Adrenaline - hormones produced by
adrenal gland part of the body's
immediate stress response and it has a
strong effect on the cells of the
cardiovascular system
ES - one of body's major info systems
that tells glands to release hormones
into bloodstream and these
hormones are carried to target
organs in body, communicates
thorugh chemicals
Hormones - chemical substances that circulate
in bloodstream and only affect target organs,
they're produced in large quantities but
disappear quickly and effects very powerful
Glands and hormones
NS and ES work to control
vital functions in body
ES works slower than NS but has
widespread and powerful effects
Glands in body (thyroid
gland) produce hormones
Hormone secreted into
bloodstream and affects any
cell with that receptor
Thyroid gland produced hormone
thyroxine which affects cell in heart
(increase HR) and affects cells in body
increasing metabolic rates and affects
growth rate
Main gland is pituitary gland (PG) in brain or
'master gland' because it controls the
release of hormones from all the other
endocrine glands in body
Fight or Flight
Endocrine and autonomic nervous
system work together during
stressful event
When stressful thing happens, hypothalamus
actives PG and activates sympathetic (f&f) state
aposed to the normal parasympathetic state (r&d)
Adrenaline gets released into
bloodstream and it triggers
physiological changes in the
body which creates
physiological arousal for F&F
This happens in an instant when threat is found
(the acute response and automatic reaction in the
body) with reactions being increased heart rate,
increased breathing rate etc
Once threat passed, the body will
return to its parasympathetic state,
its actions are antagonistic to the
sympathetic system and reduces
the activities of the body (R&D)