Nervous System Flashcards
What is the CNS made up of
Spinal chord and brain
What is the peripheral system made up of
All the other neurones
What does the peripheral system split into
Systematic nervous system and the autonomic nervous system
Systematic nervous system
Conscious control
Autonomic nervous system
Unconscious body activating
What is the autonomic nervous system made up of
Parasympathetic- slows things down - acytlcholine ….
Sympathetic-speeds things up- noradrenaline
Receptor
Specific, will only detect one type of stimulus. Can be cell or protein, transforms stimuli into electrical impulse ( chemical change)
Sensory neurone
Single long dendron, single short axon
Relay neurone
Within the CNS, many short dendrites, many short axons
Motor neurone
Many short dendrites, single long axon, ends with a neuromuscular junction
Effector
Muscle or gland, brings about a response
Potential difference
More positive ions on outside than on the inside so we say this is the resting potential
Resting potential
When,
(1) SODUIM POTASSIUM PUMP: active transport 3Na+ out, 2K+ in
(2) VOLTAGE GATED SODIUM ION CHANNEL: closed, membrane is not permeable to Na+
(3) POTASSIUM ION CHANNEL: open, some k+ diffuses out down electrochemical gradient, doesn’t reach equilibrium due to positive charge on outside
What makes up an action potential ( in order)
- Resting potential
- Generator potential
- Threshold
- Depolarisation
- Depolarisation
- Re polarisation
- Hyper polarisation
What is the refractory period
Another action potential cannot be started, makes action potentials- discrete ( don’t overlap)- unidirectional (one way)
AP:resting potential
Sodium potassium pump
Active transport
Na out
k in
AP Generator potential
Weak stimulus Some Na channels open Some Na diffuses in Does in reach threshold Nak pump stores resting potential