S03 AND S04 biological basis

human nervous system

complex network of neurons (electrochemical devices) and non-electrical glial cells that signal to each other via ligand-receptor interactions

central nervous system

spinal cord and the brain

peripheral nervous system

The system composed of the nerves outside of the brain and spinal cord; connects the parts of the body to the brain.

somatic nervous system

allows you to feel external sensations and is related to voluntary commands (one you can control)au

autonomic nervous system

allows us to feel internal sensations from and controls automatic movements of the organs, such as heartbeat.

sympathetic nervous system

A division of the autonomic nervous system that acts on blood vessels, organs, and glands in ways that prepare the body for action, especially in stressful or arousal situations. flight-or-fight response

parasympathetic nervous system

consists of motor and sensory nerves that travel throughout the body, active during rest and speeds digestion

endocrine system

a networks of glands that release blood-borne chemicals (hormones) into your blood stream. It regulates most basic biological states e.g. metabolism and blood sugar levels

• able to coordinate hormone release with CNS AND PNS

• long lasting and slower effects

microglia

a type of glial cell: immune surveillance and
eating dead tissue

Astroglia

a type of glial cell: connect neurons to blood
vessels

oligodendrocyte

a type of glial cell: myelin sheath production

dendrites

receive a chemical signal from post-synaptic terminal

axon hillock

accumulates the electrical current from the soma, if enough → an action potential

axon

the action potential propagates down the axon towards the axon terminals

myelin

an insulator of axons → faster and more effective signalling, made out of glial cells which insulate, support and nourshi neurons

glial cells purpose

serve as the cellular glue between neurons

terminal buttons

knobs found in the tips of terminal branches where chemical signalling occurs, contain synaptic vesicles

synapse

The gap where a sending neuron communicates with the dendrites or cell body of the receiving neuron.

node of ranvier

uninsulated axonal domains that are high in sodium and potassium ion channels

neurotransmitter

chemical messengers (from terminal branches)p

post-synaptic cell

respond to the neurotransmitter, either excitatory/inhibitory

sodium-potassium pump

a protein that pumps sodium ions out and potassium ion in.

• It keeps the inside of the cell more negative than the outside, which helps nerve cells send electrical signals.

• It ensures there is more sodium outside the cell and more potassium inside the cell.

action potential

a quick change in polarization in a neuron

ion channels

Allow for the exchange of ions between the intra and extracellular spaces

What leads to hyperpolarization and depolarization?

Due to ions channels (sodium and k) opening and closing

action potential propagation

postiviely charged ions coming form sodium channels, but some of these go backwards (Na+ channel refractory) and some will go forward

synaptic cleft

neurotransmitters are released to them through calcium-triggered exocytosis

inhibitory neurotransmitter

ions enter the receptor to move close the target neuron from its action potential threshold

excitatory neurotransmitter

ions enter the receptor to move further away the target neuron from action potential threshold (move the voltage)

hemisphere

left and right hemisphere + corpus callosum that connects the two brain halves together

sulcus and gurys

form the outer layers of the brain.

A gyrus is a ridge or raised fold on the surface of the brain, while a sulcus is a shallow groove or indentation between those ridges

lobe

frontal, parietal, temporal and occipital lobe: form the cerebrum

corpus callosum

supports contralateral communication between the brain and the body and sharing information

contralateral hemispheric organization

left and right hemisphere: different tasks:

• left hemisphere: lateralized language, talking, right movement and visual information

• right hemipshere: interpretation of speech, left movement and visual information

neocortex

frontal lobe and its functions

concentration, planning, problem-solving

parietal lobe functions

touch and pressure, body awareness