Week 5 - Nerves

Question 1

Where do neurons receive impulses?

Answer 1

Dendrites and cell body (perikaryon)

Question 2

Where do neurons intergrate the information given to them?

Answer 2

On their axon hillock

Question 3

What are the 3 main areas on electron microscope of synaptic junction?

Answer 3

Question 4

What are the properties of motor neurons?

Answer 4

• Large perikarya
• Nissl bodies (dark spots) in cytoplasm
• Large nuclei
• Innervate muscle cells directly

Question 5

What is the function of the axon hillock?

Answer 5

Site of action potential generation

Question 6

What is Nissl substance?

Answer 6

Rough endoplasmic reticulum

Question 7

What are the ‘rails’ and ‘vehicles’ of neurons?

Answer 7

Rails = microtubuli and neurofilaments

Vehicles = kinesin and dynein

Question 8

What are neurons completely dependent on?

Answer 8

Glial cells

Question 9

What are the proeprties of astrocytes and where are they found?

Answer 9

• Cover all surface of neuron not occupied by synapse or myelin
• Master supporters of CNS
• Take up nutrients from capillaries and provide to neurons (forms blood-brain barrier)
• Form seal on CNS surface

Glial cells

Question 10

What are the properties of oligodendrocytes and where are they found?

Answer 10

• Make myelin
• Allow saltatory conduction through myelination of neurons

Glial cells

Question 11

What are the properties of microglial cells?

Answer 11

• Function in immune system of CNS
• Use cytokines to attract other defense cells
• Can phagocytose and act as local APCs
• Role in maintenance and remodelling of CNS

Question 12

What are the properties of microglia cell nuclei?

Answer 12

• Elongated
• Dark
• No clear lining
• Sometimes granulated

Question 13

What are the proeprties of astrocyte nuclei?

Answer 13

• Larger
• Oval shaped
• Heterochromatin granules
• No visible cytoplasm

Question 14

What are the proeprties of oligodendrocyte nuclei?

Answer 14

• Round
• Dark
• Sometimes slightly granulated

Question 15

What’s the difference between wite and grey matter?

Answer 15

White = + nerve connections with + myselinsation

Grey = clusters of neurons

Question 16

What are clusters of PNS perikarya called?

Answer 16

Ganglia

Question 17

What are clusters of CNS perikarya called?

Answer 17

Nuclei

Question 18

What is an anatomical nerve?

Answer 18

Collection of axons/dendrites bundled and ensheathed into fasicles, held together by connective tissue

Question 19

What is the epineurium?

Answer 19

Partially dense, collagenous connective tissue

Question 20

What is the perineurium?

Answer 20

• Sheath with flat cells with collagen fibres between them
• Bund;es axons into fasicles, forming a seal

Question 21

What is the endoneurium?

Answer 21

Loose connective tissue between axons/dendrites within fasicles

Question 22

What is the role of satellite cells?

Answer 22

Support cells for PNS ganglia

Question 23

What is the intracellular calcium ion concentration at rest?

Answer 23

0.1uM

Question 24

What happens to airway smooth muscle when extracellular K+ ion concentration is elevated?

Answer 24

• 4-fold increase in intracellular Ca2+ ion concentration
• Muscle contraction

Question 25

What is the role of carbachol in airway contraction?

Answer 25

* Is an agonist at G protein-coupled muscarinic receptors * Produces airway smooth muscle contraction * Lower calcium ion rise

Question 26

What can block voltage-gated potassium channels?

Answer 26

TEA and 4-AP

Question 27

What does dorsal and ventral mean?

Answer 27

Dorsal = posterior Ventral = anterior

Question 28

How many vertebrae are there in each section of the spine?

Answer 28

* Cervical = 7 * Thoracic = 12 * Lumbar = 5 * Sacral = 5 * Coccygeal = 3-5

Question 29

What are the proeprties of a lumbar puncture?

Answer 29

* Locate L4 iliac crest * Isert between L4-5 * Into subarachnoid space

Question 30

What are the ascending pathways of white matter?

Answer 30

Question 31

What are the descending pathways of white matter?

Answer 31

Question 32

What is the functino of the rubrospinal pathway?

Answer 32

Large muscles of limbs

Question 33

What is the function of the corticospinal pathway of white matter?

Answer 33

Controls muscles of limbs

Question 34

What is the function of reticulospinal pathway of white matter?

Answer 34

Motor coordination, muscle tone, autonomic functions and pain

Question 35

What is the function of the vestibulospinal pathway of white matter?

Answer 35

Posture and balance

Question 36

What is the function of the tectospinal pathway of white matter?

Answer 36

Head and eye movement

Question 37

What is a spinal motor neuron?

Answer 37

Lower motor neuron

Question 38

What is a motor unit?

Answer 38

Number of muscle fibres innervated by a single spinal aloha motor neuron

Question 39

What is the function of upper motor neurons?

Answer 39

Innervate spinal motor nberons, from brain

Question 40

What is the funciton of alpha spinal motor neurons?

Answer 40

Innervate extrafusal muscle fibres responsible for contraction

Question 41

What is the funciton of small gamma spinal motor neurons?

Answer 41

Innervate intrafusal muscle fibres in muscle spindles

Question 42

What are the 3 types of reflexes?

Answer 42

* Superficial - blink, sneeze * Deep (myotactic) - patellar * Visceral (autonomic) - pupillary, bladder

Question 43

What is Babinski's relfex?

Answer 43

Flexor response = toes curl down = normal Extensor response = toes curl up = damage in adults Extensor response = normal in babies