Module 5: Neuornal communication Flashcards by Ahlam M

What is the nervous pathway

Receptor
Sensory neurone
CNS (via relay neurone) 
Motor neurone 
Effector (muscles)

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What is the function of a dendron

Sends impluse to cell body

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What is the function of the cell body

realeses neurotransmitters

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What is the function of the axon

Sends impulse away from cell body

Axon (A , away)

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What is the mylein sheath

layers of plasma membranes

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What is the function of the mylein sheath

Acts as an insulating layer
Speeds up nerve impulses transmission
at nodes of ranvier

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What makes the mylein sheath

Schwann cells

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What is the function of the nodes of ranvier

signal is transmitted across nodes of ranvier

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Draw the sensory neurone and label the parts

Go check google

labels 
cell body with nucleus 
dendrites 
cell body in the middle
axon

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Draw a motor neurone and label it

Check google

Labels
Dendrites
Cell body with nucleus
axon

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Draw a relay neurone

Check google

Labels
Cell body with nucelus in the middle with dendrites and axons surrounding
Dendrites
Axons

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What is the resting potential of a neurone

-70 milivolts

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Give the names of different sensory receptors

Mechanoreceptors
thermoreceptors
chemoreceptors
photoreceptor

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Why do sensory receptors act as transducers

able to convert kinetic energy, thermal energy, light and chemical energy into electrical impulses

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What is saltatory conduction

When impulse jumps from node of Ranvier to node of Ranvier

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What is a generator’s potential

Change in potential difference due to a stimulus,
when stimulus is detected the cell membrane gets excited and becomes more permeable allowing more ions to move in and out of cell
if the generator potential is large enough an action potential will happen

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How does the panicnium corpuscle work

Pressure to skin
causes lamellae to deform
stretch mediated sodium ion channels open
so sodium ions move in through sodium channels down electrochemical gradient
which depolarises the membrane
creates a generator potential
if generator potential is large enough it can cause an action potential

How does an action potential work

Stimulus: Excites the membrane, so Na channels open. This causes membrane to be more permeable to NA+ ions so Na+ ions move into cell, down Na ion electrochemical gradient

Depolarisation: If resting potential reaches threshold, voltage-gated sodium ion channels open, so there is a rapid influx of Na+ ions diffuse in (positive feedback),

Repolarisation: at 30mv the Na channels close, and voltage-gated K+ ions open. Membrane more permeable to K+, so K+ ions diffuse out of neurone down potassium ion conc gradient (negative feedback)

Hyperpolarisation: k+ ions channels slow to close, causing a k+ to pump out of neurone. To get to the resting potential k+/Na+ pump returns to membrane potential back to normal

What is the refactory period

Can’t be excited straight away as ion channels are recovering
acts as a time delay between one action potential and the next, so action potentials don’t overlap
Also makes sure action potential only travels one way (unidirectional)

What is a synapse

junction between 2 neurones

Name an excitory neurotransmotter

Acetylcholine

Name an inhibitory neurotransmitter

GABA

Describe synaptic transmission to a cholinergic synapse

Action potential arrives at presynaptic knob
Action potential stimulates ligand-gated channels in presynaptic neurone to open
Calcium ions diffuse into presynpatic neurone down electrochemical gradient
Influx of Ca+ ions causes vesicles to fuse with presynaptic membrane
Vesicles release ACh into synaptic cleft via exocytosis
ACh diffuses across synaptic cleft
ACh binds onto cholinergic receptors
This causes Na+ channels to open, Na+ diffuses in which causes depolarisation
If threshold is reached another action potential will be generated

How is ACh removed from the synaptic cleft

broken down by acetylcholinesterase (AChe) into choline and acetate (ethanoic acid)
This diffuses back to presynaptic neurone
ATP can be used to combine Acetate and choline back to acetylcholine

Outline the roles of synapses in nervous system

allows , neurones to communicate / cell signalling ; 2 ensure transmission (between neurones) in one direction (only) ; 3 allows , convergence / impulses from more than one neurone to be passed to a single neurone ; 4 allows , divergence / impulses from a single neurone to be passed to more than one neurone ; 5 idea that filters (out) , ‘background’ / low level , stimuli or ensures that only stimulation that is strong enough will be passed on ; 6 prevents fatigue / prevents over-stimulation ; 7 allows many low level stimuli to be amplified ; 8 idea that presence of inhibitory and stimulatory synapses allows impulses to follow specific path ; 9 permits , memory / learning / decision making ;

What is spatial summation

Multiple neurones that are connected on one single synapse they will release neurotransmitters into synapse which will trigger an action potential if it reaches the threshold allows signals from multiple stimuli to be coordinated into a single response

What is temporal summation?

multiple high-frequency impulses over time are released from the same presynaptic neurone to trigger another action potential in postsynaptic neurone

What is synaptic convergence

When multiple neurones all connect to a single neurone, causing the action potentials from multiple neurones to converge and become amplified

What is synaptic divergence

When one neurone connects to many neurones so information can be dispersed to different parts of the body

How is the nervous system organsised

Split into central and peripheral nervous system Central: Brain and spinal cord Peripheral: somatic and autonomic autonomic: parasympathetic and sympathetic

How is the nervous system organsised

Split into central and peripheral nervous system Central: Brain and spinal cord Peripheral: somatic and autonomic autonomic: parasympathetic and sympathetic

What does the somatic nervous system do

- conscious control (running etc) | - skeletal muscles

What does the autonmic nervous system do

controls unconscious activities | like heart rate, breathing, digestion

What does the parasymapthetic nervous system do

rest and digest

What does the symapthetic nervous system do

Fight or flight

What are the different parts of the brain

``` Cerebrum Hypothalamus Medulla oblongata Cerebellum Pituraity gland ```

What function does the cerebrum have

controls: voluntary actions personality learning, hearing and thinking

What function does the cerebellum do

Coordinates muscle movement | particularly balance and posture

What function does the medulla obolongata have

autonomic control | Controls heart rate, breathing rate

What function does the hypothalamaus have

Automatically maintains body temperature monitors blood glucose level produces hormones that control the pituitary gland

What function does the pituitary gland have

Split into anterior (produces hormones like FSH) and posterior glands (stores hormones made by hypothalamus like ADH) Releases hormones to stimulate other glands