Nervous System Flashcards
what is the function of nervous tissue?
Initiates and transmits nerve impulses to coordinate physiological function
What is the direction of the afferent peripheral system ?
Information from periphery to CNS to sensory nerves
What is the somatic nervous system?
skeletal muscle
What is the autonomic nervous system?
smooth muscle-gut, blood vessels, bladder
What is the direction of the efferent nervous system?
Information from CNS to periphery
What does the autonomic nervous system divide into?
sympathetic and parasympathetic nervous system
Name some parasympathetic activities?
- Constricts pupil
- Inhibits heart
- Stimulates digestive activity
- Contracts bladder
Name some sympathetic activities?
- Dilates pupil
- Acclerate heart
- Inhibits digestive activity
- Relaxes bladder
Name the cerebral hemispheres
Occipital
Temporal
Parietal
Frontal
What are the parts of the brainstem from top to bottom?
- Thalamus
- Midbrain
- Pons
- Medulla
- Spinal cord
What separates the motor and sensory areas?
Central sulcus
What generates the signals that control the execution of movement?
Precentral gyrus
What receives sensory info for touch, pressure, pain and temp?
postcentral gyrus
How many pairs of spinal nerves are there?
31
What are the functions the neuron?
- detection- receives info
- Integration- process info
- propagation- responds to info
What are the 3 neuron shapes?
- Multipolar
- Bipolar
- Pseudo-unipolar
Give examples of multipolar neurons
Motor neurons & interneurons
Give examples of bipolar neurons
Specialised sensory nerves
Give examples of pseudo-unipolar neurons
sensory nerves
What are the 2 types of synapses?
electrical and chem
What value is the resting membrane potential?
-70mV
What is the function of dendrites?
receive stimuli and spread of potential
What is the function of the axon hillock?
Trigger action potential
What is the function of the axon?
Spread of action potential and local current flow
What is the function of the synapse?
Sends signal to another neuron and to efferent organ
Explain how synapses work?
- Axon potential reaches axon terminal of presynaptic neuron
- Ca2+ enters synaptic knob
- Neurotransmitter is released by exocytosis into synaptic cleft
- Neurotransmitter binds to receptors that are an integral part of chemically gated channels on subsynaptic membrane of postsynaptic neuron
- Binding of neurotransmitter to receptor channel opens that specific channel
Name common neurotransmitters
Glutamate y-aminobutyric acid (GABA) Acetylcholine dopamine adrenaline
Name excitatory neurotransmitters
Glutamate
Name inhibitory neurotransmitters
GABA
What happens in an excitatroy synapse?
Net movement of positive ions into cell
What happens in an inhibitory synapse?
Net movement of positive ions out of cell
What is depolarisation?
Decrease in potential (membrane less neg)
What is repolarisation?
Return to resting potential after depolarisation
What is hyperpolarisation?
Increase in potential (membrane more neg)
How do voltage gated channels bring about action potential?
- All voltage gated channels closed (RP)
- @ threshold, Na+ activation opens and P Na+ rises
- Na+ enters cell causing explosive depolarisation to +30mV which generates rising phase of AP
- @ peak of AP, Na+ inactivation gate closes and P Na+ falls ending net movement of Na+ into cell. @ same time K+ activation gate opens and P K+ rises
- K+ leaves cell causing its repolarisation to RP which generates falling phase of AP
- On return to RP, Na+ activation gate closes and inactivation gate opens, resetting channel to respond to another depolarising triggering event
- Further outward movement of K+through still open K+ channel briefly hyperpolarise membrane, which generates after hyperpolarisation
- K+ activation gate closes and membrane returns to RP
