cells of the nervous system

Question 1

neuronal function

Answer 1

basic structural and functional unit; generates and conducts electrical signals; comunnicate with one another via synapse; supported by neuroglia; secretory

Question 2

neuronal structure: components

Answer 2

large nucleus, prominent nucleolus, abundant RER, well-developed Golgi, abundant mitochondria, highly organised cytoskeleton

Question 3

nueronal structure: diversity

Answer 3

similar to other cells; diversity achieved by differences in number and shape of processes determined by location and function

Question 4

consequences of neuronal diversity

Answer 4

more/less vulnerable to degeneration in CNS conditions (Alzheimers, Parkinsons, MS, ALS)

Question 5

why abundant RER and well-developed Golgi

Answer 5

larger, produces and secretes lots of proteins

Question 6

pyramidal nueronal cell features

Answer 6

primary dendrites leave at three poles - divide to secondary and tertiary dendrites

Question 7

dendrites: function and structure

Answer 7

major area of reception of incoming information; spread from cell body and branch frequently; greatly increases SA; often covered in protrusions (spines) which receive majority of synapses

Question 8

spinal plasticity

Answer 8

one of the most plastic elements of nervous system - easily damaged

Question 9

Purkinje: location, function and structure

Answer 9

in cerebellum; large inhibitory neurones; 2D spinal tree structure; responsible for fine movement

Question 10

axons: function, branching, properties, structure, location

Answer 10

conduct impulse away from cell body; emerge at axon hillock; only one per cell; may branch after leaving cell body and at target; prominent micro-tubules and neurofilaments; can be myelinated (exposed at node of Ranvier) or unmyelinated; cable properties

Question 11

why do axons have prominent microtubules

Answer 11

to transport vesicles from cell body to target

Question 12

why do axons have neurofilaments

Answer 12

high tensile strength as very thin

Question 13

axon cable properties

Answer 13

same diameter to maintain same speed of electrical conduction

Question 14

node of Ranvier: function and properties

Answer 14

where signal is amplified; where Na+ channels are present

Question 15

paranode

Answer 15

end loops of myelin attached to membrane

Question 16

juxtaparanode

Answer 16

K+ channels so gap between K+ and Na+ channels

Question 17

axon terminals

Answer 17

axon branch extensively at target; form synaptic terminals with target

Question 18

axonal damage in MS

Answer 18

axon compressed and transected so swelling at end - all vesicular proteins build up

Question 19

subtypes of neurones

Answer 19

pseudounipolar, bipolar, multipolar

Question 20

pseudounipolar: features and example

Answer 20

dorsal root ganglion; sensory neurones; two fused processes axonal in structure (bypass cell body)

Question 21

bipolar: feature and examples

Answer 21

two processes, white matter and retina

Question 22

multipolar I: features and examples

Answer 22

Golgi type I multipolar; highly branched dendritic trees; axons extend long distances; pyramidal cells of cerebral cortex; Purkinje cells of cerebellum; anterior horn of spinal cord; retinal ganglion; most susceptible to degeneration

Question 23

multipolar II: features and examples

Answer 23

Golgi type II multipolar; highly branched dendritic trees; short axons; axons terminate quite close to cell body of origin; stellate cells of cerebral cortex and cerebellum

Question 24

functional classification of neurones

Answer 24

sensory, motor and inter

Question 25

interneurones function

Answer 25

links other neurones; responsible for modification, coordination, integration, facilitation and inhibition of sensory input to give a motor output