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The Nervous System and the Endocrine System - Coggle Diagram
The Nervous System and the Endocrine System
The Nervous System
the body's primary internal communication system, made up of specialised network of cells.
based on electrical and chemical signals whereas the endocrine system is based on hormones.
the nervous system has 2 main functions:
(1) to collect & respond to info in the env.
(2) to co-ordinate the working of different organs and cells in the body.
the nervous system is divided into two subsystems:
Central Nervous System (CNS) and Peripheral Nervous System (PNS)
The Central Nervous System
CNS is made up of brain and spinal cord
Brain
= centre of all conscious awareness. Brain's outer layer (
Cerebral cortex
) = 3mm thick & covers brain like and orange peel covers an orange. it's only found in mammals.
brain is highly developed in humans & is what distinguished our high mental functions from those of other animals. few creates - sponged, sea squirts, jellyfish - do not have a brain.
brain is divided into 2
hemispheres
Spinal cord
= extension of brain. it passes messages to & from brain & connects nerves to PNS. it's also responsible for reflex action, e.g., pulling your hand away from hot plate.
The Peripheral Nervous System
PNS transmits messages via millions of
neurones
(nerve cells) to and from CNS. PNS is further subdivided into the:
Autonomic Nervous System
(ANS) = governs vital functions in body such as breather, heart rate, sexual arousal, stress response etc.
Somatic Nervous System
(SNS) = governs muscle movement & receives info from sensory receptors.
The Endocrine System
Glands and Hormones
endocrine works with nervous system to control vital functions in the body.
endocrines is slower than NS but had widespread & powerful effects.
various glands in body, e.g,
Thyroid gland
produce
Hormones
which are then secreted into bloodstream & effects any cell in body which has receptors for that specific hormone.
most hormones affects cells in more than one organ = diverse powerful responses
e.g. thyroid gland produces hormone thyroxine which affects cells in heart and cells throughout the body, increasing metabolic rates (chemical processes taking place in cells). this in turn affects growth rates.
main gland in ES =
pituitary gland
located in brain. often called the 'master gland' as it controls release of hormones from all other endocrine glands in the body.
Endocrine and ANS working together: Fight or Flight
when a stressor is perceived first thing to occur is the
hypothalamus
trigger the
pituitary gland
which then triggers activity in the
sympathetic branch
on ANS.
ANS changes from normal resting state (
parasympathetic state
) to the physiologically around
sympathetic state
Adrenaline
= stress hormone released from
adrenal medulla
(a part of the adrenal gland next to your kidneys) into bloodstream. adrenaline triggers physiological changes in body (e.g. increased HR) which creates physiological arousal necessary for
flight or fight response
immediate and automatic
- all this happens in an instant as soon as threat is detected, e.g. HR increases almost as soon as you experience a fright.
= an acute response and an automatic reaction in the body.
Parasympathetic action
- once threat has finally passed,
parasympathetic nervous system
returns body to its resting state.
parasympathetic branch of ANS works in opposition to sympathetic nervous system - it actions are antagonistic to the sympathetic system.