Muscles And Nerves

Question 0

Where are bipolar neurones found?

Answer 0

Found in sensory structures eg. Retina

Question 1

What is the main component of grey matter?

Answer 1

Mostly cell bodies - neurones.

Question 2

Where are pseudo-unipolar neurones found?

Answer 2

They are found in sensory ganglia - short axon divides into 2 branches.

Question 3

What colour does white matter usually stain?

Answer 3

Stains dark as it is mostly myelin as mostly axons.

Weigerts stain is used for myelin.

Question 4

Grey matter usually stains pale, why?

Answer 4

As it is mostly cell bodies.

Question 5

What does the epineurum cover?

Answer 5

The epineurum covers the whole nerve.

Question 6

What does the perineurium cover?

Answer 6

Covers the internal bundle of neurones

Question 7

What does the endoneurium cover?

Answer 7

Covers each individual neurone.

Question 8

What do glial cells do?

Answer 8

Glial cells regulate neurone metabolism and function, ensuring repair and recovery fro injury and regulate the blood brain barrier.

Question 9

What do astrocytes do?

Answer 9

Type of glial cell which communicates with neighbouring glial cells, regulating ion concentration by pumping K+ to capillaries.

They also convert glucose to lactate for neurones and produce growth factors for neuronal growth.

Question 10

What do oligodendrocytes do?

Answer 10

Oligodendrocytes are a type of glial cell which myelinates axons, supporting the cell.

Question 11

What do microglia do?

Answer 11

Microglia are a type of glial cells which contributes to immune defence.

Question 12

What so epndyma do?

Answer 12

They line cells for ventricle and central spinal canal. (Lining cell)

Question 13

What contributes to myelination in the CNS?

Answer 13

Oligodendrocytes myelinate in the CNS.

Question 14

What does myelination in the PNS?

Answer 14

Schwann cells perform myelination in the PNS.

Question 15

What are the nodes of ranvier?

Answer 15

The nodes of ranvier are gaps in the sheath where myelin is produced, where the neighbour Schwann cells and oligodendrocytes meet.

It is the only point for free movement of ions.

Question 16

What are ganglia?

Answer 16

Nodular masses of neurone cell bodies or supporting neuroglia.

Question 17

What do non myelinated nerves always have?

Answer 17

Non myelinated nerves always have a supporting Schwann cell.

Question 18

How does the somatic nervous system operate?

Answer 18

The somatic nervous system is voluntary and innervates striated muscles.

It contains afferent sensory fibres.

Question 19

What preganglionic fibres does the parasympathetic system have?

Answer 19

The parasympathetic system has long, myelinated preganglionic fibres.

Question 20

What is the location of ganglia in both parasympathetic and sympathetic nervous systems?

Answer 20

Parasympathetic: near or in target tissue.

Sympathetic: close to spinal cord.

Question 21

What postganglionic fibres does the sympathetic nervous system have?

Answer 21

The sympathetic system has long postganglionic fibres with many branches.

Question 22

What is a nocireceptor?

Answer 22

Nocireceptors send pain signals to the brain.

Question 23

Why do intracellular proteins make intracellular fluid negatively charged?

Answer 23

They are too big to pass through the cell membrane and they are negative charged.

Question 24

How’s does the sodium/potassium pump make the inside of a cell more negative?

Answer 24

The sodium/potassium pump, pumps 3 Na+ out and only 2K+ in.

Question 25

What is the resting potential?

Answer 25

-65mv.

Question 26

What is the significance of the refractory period?

Answer 26

The absolute refractory period ensures no further action potential can be elicited - ensures unidirectional action potential.

In a relative refractory period a larger stimulus can result in action potential.

Question 27

What are the two sensory receptors in muscles?

Answer 27

Proprioreceptors and mechanoreceptors.

Muscles spindle and muscle stimulated by stretch.

Golgi tendon organ located in tendon and stimulated by tension. Eg. Knee jerk reflex.

Question 28

What are the two types of synapses and how are they formed?

Answer 28

Electrical and chemical synapses.

Electrical formed by interlocking connexions. Gap junctions allow ions and current flow to pass directly.

Chemical synapses work by releasing neurotransmitter from synaptic vesicles on arrival of action potential.

Question 29

What is the calcium influx?

Answer 29

Action potential arrive, and voltage gated Ca2+ channels open.

Ca2+ move to active zone and fuse with membrane and vesicles taken in by endocytosis.

Question 30

What is an ionotropic receptor?

Answer 30

An ionotropic receptor is a cluster of similar subunits which depolarise or hyper polarise the postsynaptic cell.

Question 31

What are metabotrophic receptors?

Answer 31

Metabotrophic receptors are a 7 transmembrane molecule coupled to intracellular proteins that transducer a signal (slow response).

Question 32

What do Na+ and Cl- do to a postsynaptic cell?

Answer 32

Influx of Na+ causes excitory potential.

Cl- gives rise to an inhibitory effect.

Question 33

How does a depolarising mAchR agonist work?

Answer 33

Blocks ACh receptor, eg succinylcholine not metabolised as quickly.

Used as nerve gas and treatments for myasthenia gravis.

Question 34

What is Lambert-Eaton syndrome?

Answer 34

Lambert-Eaton is an autoimmune condition which inhibits Ca2+ channels and therefore ACh release.