L21 - anatomy of nervous system

Question 1

CNS

Answer 1

brain and spinal cord

Question 2

peripheral nervous system

Answer 2

all the other nerves in rest of body

Question 3

afferent neurones

Answer 3

• nerve cells receive sensory information from periphery
• provide input to the CNS
• e.g sensory neurones
  (periphery to CNS)

Question 4

efferent neurones

Answer 4

• output coming from CNS to periphery
• somatic (motor) and autonomic output

Question 5

what is somatic (motor) output?

Answer 5

movement of skeletal muscles

Question 6

autonomic (visceral) output?

Answer 6

• how brain controls internal organs
• subconscious control
  -e.g HR, BR, respiration

Question 7

spinal nerves

Answer 7

gaps in vertebrae where nerves go through

Question 8

touch and visceral input

Answer 8

• mechanoceptors (in skin for touch)
• prorioceptors (skeletal muscle)
• nociceptors (pain)
• thermoreceptors (temp)
• chemoceptors (chemicals)

Question 9

types of afferent input

Answer 9

1. touch
2. sight
3. sound
4. smell
5. taste

Question 10

dorsal

Answer 10

back part of spinal cord

Question 11

ventral

Answer 11

front

Question 12

where does information go to the in spinal cord?

Answer 12

dorsal part
- firstly passes through dorsal root ganglion (specialised axons)

Question 13

spinal efferents

Answer 13

• e.g. monosynaptic reflex

Question 14

muscle stretch (monosynaptic spinal reflex)

Answer 14

• no conscious thought
• provides output back out to periphery
• example of proprioceptors

Question 15

what is white matter?

Answer 15

where axons go through

Question 16

what is a reflex?

Answer 16

no conscious control needed

Question 17

the reflex arc

Answer 17

• receptor provides afferent input not integrative centre, providing output to an effector.
• integrative centre can be spinal cord

Question 18

ascending pathways

Answer 18

neuronal output from spinal cord to the brain

Question 19

spinothalamic pathway

Answer 19

dorsal route, how pain is detected

Question 20

descending pathway

Answer 20

info from brain to spinal cord

Question 21

cranial nerves

Answer 21

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

Question 22

what are glial cells?

Answer 22

• Non neuronal cells in CNS
• specialised to help neurones functions

Question 23

what are oligodendrocytes?

Answer 23

• glial cell
• produces myelin sheath

Question 24

astrocytes

Answer 24

• support of CNS
• buffering & scavenging
• guide developing neurones
• insulation
• immune response (microglia)
• blood brain barrier

Question 25

subarachnoid space

Answer 25

filled with cerebrospinal fluid (CSF) which is pumped through ventricles in brain. wraps all around surface of brain + spinal cord.

Question 26

csf

Answer 26

- produced by choroid plexus - 120ml volume - clear colourless solution - aq so of NaCl + glucose (some K+, Ca2+)

Question 27

function of CSF

Answer 27

- 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)

Question 28

blood supply to CNS

Answer 28

blood brain barrier