L21 - anatomy of nervous system Flashcards
CNS
brain and spinal cord
peripheral nervous system
all the other nerves in rest of body
afferent neurones
- nerve cells receive sensory information from periphery
- provide input to the CNS
- e.g sensory neurones
(periphery to CNS)
efferent neurones
- output coming from CNS to periphery
- somatic (motor) and autonomic output
what is somatic (motor) output?
movement of skeletal muscles
autonomic (visceral) output?
- how brain controls internal organs
- subconscious control
-e.g HR, BR, respiration
spinal nerves
gaps in vertebrae where nerves go through
touch and visceral input
- mechanoceptors (in skin for touch)
- prorioceptors (skeletal muscle)
- nociceptors (pain)
- thermoreceptors (temp)
- chemoceptors (chemicals)
types of afferent input
- touch
- sight
- sound
- smell
- taste
dorsal
back part of spinal cord
ventral
front
where does information go to the in spinal cord?
dorsal part
- firstly passes through dorsal root ganglion (specialised axons)
spinal efferents
- e.g. monosynaptic reflex
muscle stretch (monosynaptic spinal reflex)
- no conscious thought
- provides output back out to periphery
- example of proprioceptors
what is white matter?
where axons go through
what is a reflex?
no conscious control needed
the reflex arc
- receptor provides afferent input not integrative centre, providing output to an effector.
- integrative centre can be spinal cord
ascending pathways
neuronal output from spinal cord to the brain
spinothalamic pathway
dorsal route, how pain is detected
descending pathway
info from brain to spinal cord
cranial nerves
Cranial nerves go straight into the brain. 12 cranial nerves.
- Olfactory : nose to brain
- Optic: eyes to brain
- Oculomotor
- trochlear,abducens : movement of eye
- Glossopharyngeal
- Vagus: visceral motor neurone, automatic + subconscious effect on internal organs
what are glial cells?
- Non neuronal cells in CNS
- specialised to help neurones functions
what are oligodendrocytes?
- glial cell
- produces myelin sheath
astrocytes
- support of CNS
- buffering & scavenging
- guide developing neurones
- insulation
- immune response (microglia)
- blood brain barrier
subarachnoid space
filled with cerebrospinal fluid (CSF) which is pumped through ventricles in brain. wraps all around surface of brain + spinal cord.
csf
- produced by choroid plexus
- 120ml volume
- clear colourless solution
- aq so of NaCl + glucose (some K+, Ca2+)
function of CSF
- buoyancy + cushioning
- compensation of changes in brain volume
- diagnoses lumbar puncture
- drug delivery
- hydrocephalus ( too much CSF or it doesn’t drain away, end up with pressure on brain)
blood supply to CNS
blood brain barrier
