nervous system

1 axon, many dendrites

Astrocyte - growth support Oligodendrocyte - myelin forming cell, wraps around axons Microglia - immune function in brain Ependymal cells - specialised epithelial cells, secrets cerebral spinal fluid. IN the PN: Schwann cells - myelin forming cell and growth forming and immune role.

Cell bodies of neurones reside in gray matter. Gray matter is on the inside of the spinal cord (but outside the brain)

Myelinated axons exist. The myelinated phenotype from the oligodendricytes provide lipid covering, a rich white colour White matter is on the outside of the spinal cord (inside of the braiN)

Cerebrum Diencephalon (middle of brain, above brain stem) Brain stem Cerebellum (behind brain stem)

Frontal lobe Parietal lobe Temporal lobe Occipital lobe

Allow “more substance in a closed space.” Allows the tissue to fold in on itself on the brain. Sulci - infoldings of the cerebral hemispheres that form “valleys” between the gyri. (The valleys between the mountains) Gyri - The ridges of the infolded cerebral cortex (it’s the tissue itself, the mountain)

Frontal lobe - motor function Parietal lobe - somatosensory cortex. Occipital lobe - vision Temporal - auditory

Thalamus - major relay station for sensory information coming into the cortex from below (e.g spinal cord and brain stem) - it’s a gate for how many information is coming into the somatosensory cortex. Olfaction doesn’t go through here Hypothalamus - Autonomic control center - works with endocrine system, helps body sit in homeostasis

Less evolved species have a brain stem because it’s the most primitive area of the brain. Attaches spinal cord to cerebellum and cerebrum. • mid brain - eye movement • pons - major relay area between cerebellum and cerebrum • Medulla oblongata - control center for involuntary function (houses vital center e.g blood pressure, and non-vital centers e.g sneezing) Cerebellum - balance and coordination

Cervical area - neck thoracic area - chest cavity lumbar sarcral area

Bone: skull protecting brain, vetrebal column protecting spinal cord Meninges: cellular layers that surround the tissue, they come in 3 different layer. • Dura: outer. Tough structural layer, attaches tissue to bone • Arachnoid: Close to dura, web-like appearance. • Pia: deepest layer, external layer of brain and spinal cord.

Because of the arachnoid web like appearance, there’s a lot of space between it. This space contains fluid (CSF)

Protective layer. Cell-free fluid

A barrier composed of endothelial cells and astrocytes. Prevents free diffusion into the brain by large molecules (>500 daltons MW) E.g O2, CO2, lipid soluble molecules (hormones can enter

A brief change in electrical potential across the cell’s membrane involving the movement of ions across the membrane in response to stimulation.

Where the cell sits when it’s not excited. -70mV (need to know it’s negative). mV used to characterize membrane potential.

Na+ and Cl - This diagram is on ON

Sodium potassium ATPASS active because it requires ATP, Able to pull 3Na+ out, and 2K+ in. This is used in CV system.

Na+ movement is largely responsible for an action potential (e.g an increase in intracellular Na+ produces an action potential) K+ is mainly responsible for resting membrane potential

a capacitor which STORES electrical charge.

• positive feedback • • Myelination (fatty substance), increases ratio of outwardsResistance/InwardsResistance, helps to insulate even further where the AP’s occur on the axons. Increased resistance = faster action potential

Little gaps between the myelin. At each node there are a huge abundance of voltage gated sodium channels. There’s a high level of insulation and so an action potential happens at a node and then it jumps to the other node The AP travels in a “saltatory conduction” manner

Pain fibres. Sensory fibres AP travels in a “continuous conduction” manner, it’s much slower than saltatory.