Zusammenfassung der Ressource
2.1 The Nervous System and Endocrine
System
- The Nervous System
- A specialised network of cells in the human
body. Two main functions:
- To collect, process and respond to
information in the environment
- To co-ordinate the working of different
organs and cells in the body.
- CNS
- Complex processing. Involves the brain (the centre
of all conscious and most unconscious processing)
and the spinal cord (receives and transmits
information)
- Similarities
- Brainstem and spinal cord
both control involuntary
processes
- Differences
- The brain provides conscious
awareness and allows for higher
order thinking.
- The brain consists of multiple regions
responsible for different functions, whereas the
spinal cord has one main function.
- Brain
- Centre of awareness. Divided
into two hemispheres.
Cerebral cortex is more
developed in humans than in
other animals.
- Spinal Cord
- Extension of the brain. It transports messages to and
from the brain to the peripheral nervous system. It is
also responsible for reflexes.
- PNS
- Function: To
connect the brain
and spinal cord to
the rest of the body
and the external
environment.
- Somatic Nervous System
- Connects the CNS with the senses.
Controls muscle movement.
- Autonomic Nervous System
- Governs vital functions in the body such as
breathing, heart rate, digestion, sexual arousal
and stress receptors. Involuntary system, not
under conscious control.
- Sympathetic
- Involved in preparing the body
for fight or flight
- Heart rate increases, sweat
increases, breathing rate
increases, dilates pupils, inhibits
digestion.
- Parasympathetic
- Used to return the body back to
its normal state after fight or
flight response.
- Herat rate decreases, Sweat
decrease, breathing rate
decrease, constricts pupils,
stimulates digestion.
- Similarities
- Sympathetic nervous
system and the somatic
nervous system respond to
external stimuli.
- Sympathetic responds by preparing
body for fight or flight.
- Somatic responds to
external stimuli by
carrying information.
- Differences
- Autonomic consists of
two sub components.
- Somatic has sensory and
motor pathways.
- Autonomic controls internal organs and
glands, whilst somatic nervous system
controls muscles and movement.
- The Endocrine System
- Series of glands located across the
body which release hormones. These
enter the bloodstream and send
messages to other parts of the body.
- Homeostasis
- Regulation of the internal
environment. In normal
conditions there is a balance
between the sympathetic and
parasympathetic systems.
- 1. Stimulus produces change in variable. 2. Change detected by
receptor. 3. Input information sent along different pathway to control
centre. 4. Output, information sent along efferent pathway to effector.
5. Response feeds back to influence magnitude of stimulus,
- Glands
- Hypothalamus
- Connected to the pituitary gland and is responsible for stimulating
or controlling the release of hormones from the pituitary gland.
- Pituitary Gland
- Sometimes known as the master gland, hormones released by the
pituitary gland control and stimulate the release of other hormones.
- Anterior- releases adrenocortical trophic hormone
(ACTH) stimulating release of cortisol.
- Posterior lobe- releases oxytocin
responsible for uterus contractions.
- Pineal Gland
- Releases melatonin
- Thyroid Gland
- Releases thyroxine which regulates metabolism.
- Adrenal Gland
- Adrenal Medulla
- Releases adrenaline and noradrenaline
- Adrenal Cortex
- Releases cortisol which
stimulates the release of glucose.
- Differences between the systems
- Nervous System
- Electrical Impulses
- Short lived
- Quick
- Temporary and localised
- Endocrine System
- Chemical messengers
- Long-lasting effects
- Takes longer
- More permanent
and wide
- Fight or Flight
- Sympathomedullary Pathway
- Hypothalamus activates the
adrenal medulla
- Adrenal medulla releases adrenaline and
noradrenaline into the bloodstream
- Body prepares for fight or flight. Adrenaline and Noradrenaline
reinforces the pattern of sympathetic activation
- Energy
- Pituitary- Adrenal System
- Higher brain centres
activate hypothalamus.
- Hypothalamus releases cotricotrophin.
- Pituitary gland releases
adrenocorticotrophic hormone
- Adrenal cortex releases corticosteroids
- Liver releases energy and the immune system is suppressed.
- Effects of Adrenaline and Noradrenaline
- - Increased blood flow to the brain and
skeletal muscles for quick thinking.
- - Decreased blood flow to systems that
are not time critical, EG skin and
digestive system
- -Dilated pupils for improved vision and faster breathing
rate for increased oxygen in the blood.
- -Psychological effects of increased anxiety,
attention and increased alertness