13: Neurology

Question 1

CNS

Answer 1

• Central Nervous System

- Consists of the spinal cord and the brain

Question 2

PNS

Answer 2

• Peripheral Nervous System

- Nerves connecting to the CNS that are sensory neurons & motor neurones connecting to effectors

Question 3

Somatic Nervous System

Answer 3

-Conscious movements/actions that is voluntary

Question 4

Automatic Nervous System

Answer 4

• Involuntary unconscious actions (heart beat, myotatic reflex)
• subconscious

Question 5

What is the automatic nervous systems sub sections?

Answer 5

• Sympathetic

- Parasympathetic

Question 6

Sympathetic motor system

Answer 6

• Involves noradrenaline being released

- This leads to an increase in the activity of the effectors

Question 7

Parasympathetic motor system

Answer 7

• Involves the neurotransmitter ACh ( Acetylcholine )

- This leads to relaxing of the effectors

Question 8

Structures in the Human Brain

Answer 8

• Skull
• Dura
• Cerebrum
• Cerebellum
• Corpus Callosum
• Medulla oblongata
• Hypothalamus
• Pituitary Gland

Question 9

How is a resting potential maintained?

Answer 9

-Na+ and K+ ion pumps maintain the resting potential

Question 10

Structural similarities between sensory and motor neurones.

Answer 10

• Soma (cell body)
• Axon(s)
• Dendrites
• Voltage gated K+ and Na+ ion channels
• myelin sheath
• Schwann Cells (glial cells)

Question 11

Why is the Pacinian corpuscle described as a transducer?

Answer 11

-Converts mechanical energy into electrical energy (action potentials)

Question 12

How is the strength and intensity of a stimulus relayed to the brain?

Answer 12

• The frequency of action potentials propagated

- The higher the frequency the stronger the stimulus

Question 13

The roles of synapses

Answer 13

• Allows for cell signalling
• Unidirectional
• Filter low level stimuli
• enables memories
• Prevents over stimulation
• Allows for low level stimuli to be amplified
• Allows for the convergence/divergence of impulses

Question 14

Explain the difference between the speed of conduction of an action potential in a myelinated and non-myelinated neurone

Answer 14

• Conduction is faster in the myelinated part of the neurone (larger membrane resistance smaller axial resistance)
• Action potential can only be generated at the nodes of Ranvier in myelinated
• Longer Local circuits
• Ion movement can only happen at the nodes
• Saltatory conduction (jumping from node to node)

Question 15

How can a toxin interfere with the release of neurotransmitters?

Answer 15

• interfere with the binding of the vesicle to the pre-synaptic membrane
• interfere with the movement of Ca+ ions
• interfere with the reuptake of the neurotransmitters
• interfere with the formation of endosomes (vesicles)

Question 16

State how the NERVOUS system decreases the heart rate

Answer 16

• Impulses along a parasympathetic nerve

- The C10 Nerve (vagus nerve)

Question 17

Structures in a sensory neurone

Answer 17

• dendrites
• dendrons
• soma (cell body)
• axon

Question 18

How is a resting potential established and maintained?

Answer 18

• sodium-potassium pumps actively pumps Na+ K+ ions
• Move Na+ out of the cell and K+ into the cell
• Voltage gated ion channels allow for passive diffusion of ions
• Maintained by more sodium ion channel becoming closed so low permeability of Na+ ions
• Inhibition of the movement of chloride ions out of the cells to maintain an electrochemical balance

Question 19

What is the relationship between the strength of a stimulus and the resulting action potential?

Answer 19

• Strong enough stimulus can trigger an action potential
• The strength of a stimuli is related to the frequency of action potentials (higher frequency stronger the stimulus)
• the depolarisation needs to reach the threshold value (all or nothing)
• action potentials are the same size