The Brain and Nervous system Flashcards
Function of the Sympathetic autonomic Nervous System-
-thoracic and lumbar regions-increase blood pressure /heart rate etc
Function of the parasympathetic autonomic nervous system-
-Cranial and Sacral , Slows blood pressure/heart rate etc
Layers of a nerve -
Epineurium - Perineurium - Endoneurium.
- Draw a Neurone
…..
Outline a nerve impulse -
- Stimuli = sodium channerls open
- na+ rush into cell
- Depolarisation
- Equilibrium
- Na channels close
- Potassium channels open
- K+ moves out of the cell
- Repolarisation occurs
- K channels are slow to close
- Hyperpolarisation occurs
What is the resting potential of a neurone?
-70mV
Continuous vs saltatory conduction
When an action potential in an axon spreads to a neighboring region of its membrane by a series of small steps eg the opening of na+ channels, the process is called continuous propagation. When it propagates by jumping from one site eg nodes of ranvier to another along the axon, the process is called saltatory propagation
Give the role of chemical synapses-
- Presynaptic cell releases naurotransmitters
- Act on the postsynaptic cell
- Neurotransmitters can excite or inhibit
- Neurotransmitters - Acetylcholine , Serotonin, Norepinepherine , dopamine , GABA
Give the mechanism for the transmission of neuro-transmitters -
- Transmitters is synthesised and then stored in vesicles
-Action potential in presynaptic terminal
-Depolarisation causes voltage-gated ca2+ channels
-Influx of ca2+
-causing vesicles to fuse with presynaptic membrane.
-Transmitter is released into synaptic cleft
-Transmitter binds to receptor molecules in postsynaptic membrane
-Postsynaptic current causes excitatory or inhibitory postsynaptic potential that changes the excitability of the postsynaptic cell.
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Types of damage to neurone-
1- Chromatolysis- occurs shortly after axon damage.
2-Wallerian degenerarion- distal portion degrades
3- Axon regeneration- intact neurolemma cells divide , formation of regeneratio tube, nex axon will form
4- Re-Myelination , eventually myelin reforms too
Types of injury to neurone-
- Transient ischaemia - lack of oxygen
- Neuropraxia -Compression , take up to 6-8 weeks
- Axonotmesis- Axon is damaged
- Neurotmesis - Severed nerve , can be repaired through surgery.
Outline the role of the Frontal lobe in the brain-
- Primary motor cortex
- Premotor cortex
- Control of behaviour
- Personality/emotion
- Memory
- Broca’s area - speech
- premotor area- Initiation/planning of movement
- Primary motor cortex- Voluntary movement.
Outline the role of the Parietal lobe-
- Somatic sensation
- Sensory Cortex
- Origin , shape , pressure , texture
- Body awareness and spatial awareness
Outline the role of the temporal lobe-
- Interpretation of speech and sound
- primary auditory area
- Wernickes Area - determines if sound is speech , music or noise , interprets meaning of speech
- Memory
Outline the role of the Occipital lobe-
- Visual Input
- Intensity of light and dark , shape of movement of object
- relates past visual experiences with recognition and evaluation
Outline the role of the Brain mid stem-
- Midbrain
- Pons
- Medulla
- Sensory pathways
- motor pathways
- important control centres
- Nuclei of cranial nerves