Nervous system:

• Soma = cell body, includes the nucleus and all other organelle.
• Schwann cells are encased in myelin for conduction and insulation.
• Nodes of ranvier = saltatory conduction.
• Dendrites on one neurone connect to the axon terminal on the next neurone.
• Nissl body = groups of ribosome in the ER.
• Gray matter = regions of many cell bodies and dendrites.
• White matter = regions with many axons - white from myelin.
• Brain = gray matter - outside and white matter - inside.
• Spinal cord = gray matter - inside and white matter - outside.
• CNS = brain + spinal cord, sensory/motor/association centres, coordinates PNS messages, lower centres have signals with direct PNS contact and higher centres go through lower centres first.
• Meninges have 3 layers which surround the brain beneath the skull: dura matter, arachnoid and pia matter.
• Dura matter = thick/tough, collagen and elastin.
• Arachnoid = attached to the inner surface of the dura matter.
• Pia matter = sheath around the nervous matter.
• Telencephalon = cerebral hemispheres and olfactory bulbs.
• Diencephalon = thalamus, epithalamus, hypothalamus and pituitary region.
• Mesencephalon = intermediate location.
• Metencephalon = cerebellum and pons.
• Myencephalon = medulla oblongata.
• Forebrain/cerebrum = 2 hemispheres divided by longitudinal fissure, 4 lobes, cerebral cortex, perceives sensory information, controls - cognitive, sensory and motor function.
• Longitudinal fissure (cerebrum) = corpus calliousum is the connection.
• Cerebrum controls = memory, instinct, will, emotions and behaviour.
• Forebrain Hypothalamus = controls homeostasis, link between the nervous and endocrine system and is in the ANS.
• Forebrain Thalamus = relay centre for nerve centres, specialist nerve bodies and information on internal/external environments (pain/pleasure).
• Midbrain - Tectum + Tegmentum = pass information gathered from the external environment to the cerebrum.
• Hindbrain - Pons = connects left/right hemispheres along the corpus callosum and is subconscious control.
• Hindbrain - Cerebellum = balance/control, muscular posture and coordination can suffer with damage.
• Hindbrain - Medulla Oblongata = controls impulses and connects the brains to the spinal cord.
• Spinal cord = spinal nerves branch, nerve pairs correlate to the vertebrae, cervical region - above vertebrae and thoracic vertebrae is below vertebrae. (connects brain to CNS).
• Conus medullaris = thickening/tapering of the cord end - L1 + L2 vertebrae.
• Cauda equina = after the cord ends it's the collection of spinal nerves.
• PNS = somatic + autonomic, 12 cranial nerve pairs, 42 spinal nerve pairs and one for each foramina.
• Bachial plexus = forelimb, last 3 cervical and first 2 thoracic vertebrae.
• Lumbosacral plexus = hindlimb, last 3 lumbar and first 2 sacral vertebrae.
• ANS = sympathetic and parasympathetic.
• Functions of the nervous system = initiate/regulate movement by initiating/regulating muscle contraction, regulates gland secretion, 5 senses/mechanisms to detect pain, temperature, pleasure and chemicals, maintain consciousness and generate behaviours to survive.
• Neurone excitability = neurones experience depolarisation and action potentials which generate impulses.
• PNS enteric NS = partially autonomous collection of neurons in the GI tract.
• Dendrites = transmit electrical signals towards the cell body.
• Axons = conduct electrical signals away from the cell body.