Neurobiology - week 13 Flashcards
How is the nervous system organised?
Stimuli > sensory > centeral processing > Motor > muscle
Structure of basic neuron? (6 parts)
Dendrites (receive messages) Cell body (cell life/ support centre) Neural impulse (electrical signal) Axon (Pass messages) Myelin sheath (Speeds up neural connections) Axon terminals
Define membrane potenial?
electrical potential difference or the voltage between the inside and outside of a cell
Resting membrane potenial?
How do you keep the resting membrane potential?
70 mV
Concentration pulls K+ / Negative charge pulls K+ in
K+ > Na+ leaky channels = resting membrane more permeable to K+
What is active pumping?
Long term membrane regulation
Sets up the potential difference across the membrane (Na/K+ pump)
Hyperpolarisation
Depolarisation
(passive process)
Hyper: After action potenial (down dip) Less K+ leaves the cell
De: After hyper (rises above -70mV briefly) Less electrical gradient bring K+ back into the cell
Nerve impulses/ action potenial/ spikes are what?
Neurons modes of communication
What is the axon hillock?
What are key features of axons?
What is saltory conduction?
Where action potenial is generated (high Nav density).
Self sustaining refractory, inactivation of Nav and opening of K+ channels, Bi-direction, leaky channels
When action potential jumps from node to node over myelin sheath
Recall the synaptic cleft
Look up pictures, post synaptic and active presynaptic neuron
What is Temporal summation?
Post synaptic potenial at same synapse occur in rapid succession. Can occur for both IPSP and EPSP
What is spatial summation?
Mulitple postsynaptic potenial from different synapes occur about the same time and sim EPSP and IPSP can channel each other out or add up
An EPSP on an individual synapes is often not strong enough to trigger and action potential
How muscles contract?
H and Z bands shrink during muscle contraction.
Controlled by sacroplasmic reticulum and transverse tubules
Ca2+ brings about what?
Excitation- contraction coupling = transductino stage
Invertibrates neurotransmitters release what
Glutamate
True or false
In vertibrates, each motor neuron innervates only one muscle fibre
true
Size prinicple, small neurons recruited before larger ones
Weak connections recuit what?
Strong connection recuit what?
Few motor neurons
Many motor neurons
Who has the simplest brain/ CNS?
What is their specialisation
Cnidarians (hydra/ jellyfish)
Giant axons large diameter, fast impulse for esape resposne
Platyhelminthes have what brain/ cns
collection of neurons form small brain, clearly defined nerve cord
Arthropods specialisation
Specialised sensory organs, body more condensed, similar layout with ganglion with two regions
Tract and neurophil
3 sections of mammal brain
Forebrain - prosencephalon
Midbrain - mesencephalo
Hindbrain - rhombencephalon
Sensory is Afferent and …
Motor is Efferent
Functions of
Sympathetic
and Parasympathetic
Fight or flight. Dialate, stop secretion, speed up heart
Rest/ respoosnse. Constrict, secrete saliva, slow down heart
Cranial nerves do what
Carry info straight to the brain (12 ish pairs)
