Nervous system Flashcards
Components of the CNS?
Brain and spinal cord
2 parts of the PNS?
Afferent nerves (sensory)
Efferent nerves (motor)
characteristics of a neuron?
- highly specialised
- surrounded by myelin sheath
- used for communication
what produces myelin?
PNS - schwann cells
CNS - oligodendrocytes
components of a neuron and their functions
Body (soma) = control centre, nucleus
Dendrite = branch that receives impulses
Axons = axonal hillock, transmits signals
what are nerves?
- bundle of fibres
What is the resting potential of a neuron?
-70mV
Which way do action potentials travel?
From dendrites to axons
What are nerve impulses?
A change in membrane potential which allows signalling or excitation
What is a synapse?
Where one neurone meets another
What is a neurotransmitter?
Chemical signal triggered by an action potential
How does depolarisation of nerves occur?
Impulse reaches pre-synapse and binds to post-synaptic receptors
What is summation?
Combination/sum of all graded potentials in the post-synaptic neuron
what do nerves do?
- sends impulses from CNS to body
what is the epineurium?
layer that covers each nerve by connective tissue
what is the perineurium?
complete sleeve around the axon bundle
what is the endoneurium?
covers each fibre, fluid
what is the fascicle (PNS) and tract (CNS)?
small bundle of axons
2 divisions of the peripheral nervous system?
somatic and autonomic
2 parts of the autonomic system?
sympathetic and parasympathetic
what are astrocytes?
physical barrier that support neurones
what do astrocytes do?
enable homeostasis and reuptake of neurotransmitters
what are microglia?
immune cells of the brain
3 types of functional neurones?
afferent (sensory)
efferent (motor)
interneurons
what do afferent neurones do?
send signals from periphery to CNS (Sense)
what do efferent neurones do?
send signals from CNS to muscles/skin (respond)
what do interneurons do?
connect brain and spinal cord in CNS
what do nerves do?
conduct impulses between brain/spinal cord and body
what does an action potential change the membrane potential to?
+30mV
how are electrical impulses formed?
by ions moving into the neuron
what does dendritic depolarisation do?
opens voltage gated sodium channels
why can an action potential only move one way?
change in membrane potential causes more Na+ channels to open
channels behind the Ap become inactive
what is the grey matter of the brain?
cortex containing nerve cell bodies
what is the white matter of the brain?
axons
what does the brain stem control?
involuntary functions, blood pressure, breathing
what does the cerebellum do?
co-ordinates balance and movement
what does the diencephalon control?
homeostasis
what is the basal ganglia for?
motor control
2 parts of limbic system?
amygdala - emotion and memory
hippocampus - learning and memory
3 parts of the cerebrum?
basal ganglia
limbic system
pituitary gland
where do sensory nerves enter spinal cord?
dorsal root
where do motor nerves enter spinal cord?
enteral root
what are peripheral nerves?
nerves that branch off from spinal cord
what do visceral sensory neurons monitor?
pain, temp, irritation
what is visceral reflex?
reflex arc of autonomic nervous system
effector neurotransmitter of sympathetic system?
noradrenaline (norepinephrine)
effector neurotransmitter of parasympathetic system?
acetylcholine
what class are the postganglionic nerves in the sympathetic system?
adrenergic
