5.1.3 Neuronal Communication, Structure + Function Of Neurones

Question 1

Chemoreceptors function and location?

Answer 1

Detect chemical changes and stimuli, environment or blood; found in taste buds, olfactory epithelium, aortic and carotiod bodies (ions in blood)

Question 2

Photoreceptors function and location?

Answer 2

Detect light energy, depth perception (rods), colours (cones); rod and cone cells in the retina

Question 3

Thermoreceptors function and location?

Answer 3

Respond to heat and cold; found everywhere in the body

Question 4

Mechanoreceptors function and location?

Answer 4

Detect mechanical deformation of receptor cell membrane- balance and pressure; touch and pressure receptors in the skin, hair cells in the inner ear

Question 5

Nocioreceptors function and location?

Answer 5

Pain receptors, intense stimuli required for activation; skin and the inside of the body

Question 6

Sensory receptors

Answer 6

Detect changes in an environment; transducers that convert one form of energy to another (action potential); change in energy level acts as stimulus

Question 7

Proprioceptors function and location?

Answer 7

Provide a sense of body position and allow fine control of body movements, eg balance; muscle spindles, Golgi tendon organs, joint receptors, general muscle

Question 8

Myelinated nerve structure?

Answer 8

Schwann cells wrapped tightly around axon several times; spiral; 1/3 of peripheral nerves in vertebrates and myelinated

Question 9

Non-myelinated nerve structure?

Answer 9

Still have Schwann cells; many neurones may be loosely wrapped in one Schwann cell; action potential travels in a wave instead of jumping (diffusion)

Question 10

Pacinian corpuscle structure? (Pressure receptor)

Answer 10

Found in skin; myelinated single nerve fibre, surrounded by a capsule formed of lamellae with blood vessels throughout; layers get squished together and an action potential is sent

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Question 11

Sensory neurone structure?

Answer 11

Denrites -> myelinated axon -> nucleus and cell body -> myelinated axon -> axon terminal

Question 12

Relay neurone structure?

Answer 12

Nucleus and cell body in centre; dendrites coming in; one axon going out; fried egg

Question 13

Motor neurone structure?

Answer 13

Dendrites attached to cell body and nucleus -> myelinated axon -> axon terminal

Question 14

Nucleus of nerve cells does?

Answer 14

Contain DNA and controls protein manufacturing; directs cell metabolism; no role in cell signalling

Question 15

Nerve cells are unable to…

Answer 15

Go through mitosis; come from stem cells as a foetus; cannot produce new nerve cells once matured; cannot regrow once damaged

Question 16

Cell body function?

Answer 16

Contains nucleus; round and centrally located

Question 17

Dendrites function?

Answer 17

Can create new links, information forgotten wen they go; collect information; inputs from receptors and CNS; enough inputs generate an action potential to pass to other cells

Question 18

Myelin sheath function?

Answer 18

Insulates axon and speeds up signal; white fatty casing

Question 19

Schwann cells function?

Answer 19

Individual cells that make up the myelin sheath; speeds up signal

Question 20

Node of Ranvier?

Answer 20

Gaps between Schwann cells, allow action potential to jump between and move quickly

Question 21

Axon function?

Answer 21

Tube through myelin; carries action potential

Question 22

Axon terminal function?

Answer 22

Sends message to effector

Question 23

Myelinated nerves features?

Answer 23

Can transmit impulses at 100-120ms^-1; can be up to 1m long; impulses can travel from sensory neurones to CNS and effectors; used in movement; quicker and longer

Question 24

Unmyelinated nerves features?

Answer 24

Impulses transmitted at 2-20ms^-1; neurones are shorter; coordinate bodily functions, eg digestion and breathing; slower and shorter