Biology- The Human nervous system
- Created by: elliph
- Created on: 12-04-16 16:39
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- Human Nervous System
- System
- Stimulus
- Receptor
- Coordinator
- Effector
- Response
- Nerve cells
- Sensory neurone
- have long dendrons
- myelinated
- Cell body
- Axon
- From receptors to all over body
- Relay neurone
- smaller, many interconnections
- 99.9% or neurones are relay
- Motor neurone
- Long axons
- From CNS to effectors
- Sensory neurone
- Impulses
- Membrane Polarised
- Difference in charge
- resting potential -70mV
- Na+, K+ pumps use active transport to move 3 Na= out and 2 K+ in.
- K+ pump use facilitated diffusion to pump K+ out.
- Polerisation
- Depolarisation
- Repolarisation
- Hyperpolarisation
- Untitled
- Action potential
- Refractory period so no back fires can occur
- All-or-nothing nature
- Myelination makes impulses faster
- Axon Diameter means less resistance
- Temperature increases the speed of the impulse
- Membrane Polarised
- Synaptic transmission
- Synapse= junction between neurones and next cell
- Synaptic cleft
- Synaptic knob- presynaptic membrane only
- Neurotransmitters
- exitatory
- depolarise
- inhibitory
- hyperpolarise
- exitatory
- action potential
- Receptors- postsynaptic membrane only
- Acetylcholine
- Calcium ions
- Synapses
- Drugs
- some mimic the shape of receptors
- some block receptors
- some inhibit the enzyme that breaks down neurotransmitters
- Summation
- Spatial summation
- Many neurones connect to one
- small amount each, together reaches threshold
- if some inhibitory, makes less likely to reach threshold
- Temporal summation
- 2 or more impulses arrive in quick succession
- more neurotransmitters released
- Spatial summation
- Drugs
- System
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