The nervous system-is very complex but it can be broken down into these 2 factors:
Central nervous system (CNS)- most commonly consists of brain and spinal cord. Brain is contained in the
cranial cavity. Brain is very fragile but it is protected by the skull and acts as a helmet. Spinal cord is
protected by vertebrae. Having our skull there I also sometimes bad, there is a solution between our brain
and skull (spinal fluid, which is primarily salt water) therefore the brain floats in the skull, if you have an
abrupt impact (car accident at 100kms/hr), everything in the skull still moves, it then swells and if you don’t
reduce the swelling, your brain will get compromised from the lack of space.
Peripheral Nervous System (PNS) is a somatic and autonomic nervous system. Somatic known as
voluntary, connects brain to voluntary muscles; provides sensory feedback about voluntary movement
(knowing hand is holding pen), less protected than CNS (without the skull etc)
Autonomic known as involuntary, connects brain to internal organs (you really have no control over this).
Further divided to sympathetic (responds to danger and stress, heart rate, adrenaline (fight or flight)) and
parasympathetic (controls organs at baseline (standard). Opposite to what sympathetic nervous system,
activated when person feels relaxed, stimulates digestion (rest and digest)).
Brain: 3 sections
o Medulla basic things, automatic, heart rate, blood pressure, CO2/O2.
o Pons-Linked to hindbrain and midbrain together, helps control respiration
o Cerebellum-Coordinated voluntary muscle movement, balance, muscle tone, posture
o Relay of sensory and motor information between forebrain and hindbrain
o Visual and auditory reflexes
o Production of DA in substantia nigra
o Dience phalon: Contains thalamus and hypothalamus:
o Thalamus: Primary and important relay sensation, spatial sense (where are you in the room)
and motor signals to the cerebral cortex, regulation of consciousness, sleep, alertness
o It does a lot of things the ‘old’ brain would do (things you wouldn’t think about)
o Hypothalamus- Regulates parts of medulla that control cardiac function, blood pressure,
respiration, regulation of water balance, appetite and sexual desire. Link to endocrine system
VIA pituitary gland.
o Telencephalon contains left and right cerebral cortex (involved in higher order intelligence,
memory, personality, these are the things that change the most (new). Processes sensory and
motor information, contains 4 lobes, and each has its own memory storage and is associated
with particular functions: Frontal (Motor cortex-coordinated voluntary movement) Parietal
(Somatosensory cortex-sensations of touch, pain temperature and pressure are associated)
Temporal Lobe (Contains cortical cues and is responsible for auditory and smell impulses)
Occupational lobe (visual cortex, visual impulses) Basic Ganglia (4 round masses embedded
deep in cerebrum, helps make muscle contractions orderly, smooth and purposeful
Neurotransmitter (NTs): regulates CNS and PNS function therefore it affects the whole body. Sympathetic
nervous system secret