Nervous System

Question 0

What is temporal summation?

Answer 0

When excitatory and inhibitory inputs summate with respect to time of arrival at the cell body or dendrite

Question 1

What is input summation?

Answer 1

When various types of neurones act together to receive most of the impulses converging on the nerve

Question 2

What are the functions of the axons?

Answer 2

Summate inputs, initiate action potentials, conduct action potentials away from the cell body to terminals, depolarisation of terminals, communication with follower cell

Question 3

Where do peripheral nerves originate?

Answer 3

Either spinal cord or cranium

Question 4

Describe sensory neurones

Answer 4

Pseudo-unipolar, transduce energy into electrical impulses, receptor - acts as a transducer between forms of energy.

Question 5

What direction do sensory neurones relay electrical impulses?

Answer 5

Cell body - spinal cord - brain (Afferent)

Question 6

Describe interneurones

Answer 6

Multi-polar, smallest neurones, within brain or spinal cord, relay information between sensory and motor neurones, most complex neurones in the nervous system

Question 7

What are the characteristics of the membranes of neurones?

Answer 7

Bi-lipid - selectively permeable. Ionic concentration gradient - electrochemical gradient therefore neurones are electrically charged

Question 8

What is the function of astrocytes?

Answer 8

Transfer of nutrients and waste products between neurones and blood, BBB, phagocytic. Offer physical support.

Question 9

Describe motor neurones

Answer 9

Multipolar, largest neurones in the NS

Question 10

What direction do motor neurones relay electrical impulses?

Answer 10

Brain - muscles (Efferents)

Question 11

What are the functions of neuroglia?

Answer 11

Support neurones in CNS/PNS and insulate neurones in CNS/PNS

Question 12

What are oligodendrocytes?

Answer 12

Neuroglia which provide myelination

Question 13

What do ependyma cells do?

Answer 13

Line ventricles and central canal of spinal cord for circulation of CSF

Question 14

What do microglia do?

Answer 14

Provide immunity and phagocytic effects at sites of damage in neurones

Question 15

What do schwann cells do?

Answer 15

Main function is insulation of peripheral nerve axons thereefore speeding up the conduction of action potentials

Question 16

What do satellite cells do?

Answer 16

Physical support of neurones in peripheral nervous system

Question 17

What are the results of an over active parasympathetic nervous system?

Answer 17

Dilated blood vessels, infections, less substrate available for the brain

Question 18

What are the results of an over active sympathetic nervous system?

Answer 18

Constriction of blood vessels, shortage of supply to tissues which can results in gangrenous peripheries

Question 19

Describe the structure of the neurones in the parasympathetic nervous system

Answer 19

Messages from brain and spinal cord, cranial - sacral division, pre-ganglion is long and cholingeric. Post-ganglion express nicotinic receptors and are cholingeric.

Question 20

Describe the structure of neurones in the sympathetic nervous system

Answer 20

Pre-ganglionic are cholingeric, post-ganglionic are noradrenegenic. Pre-ganglions express nicotinic receptors. Some synapses are cholingeric - sweat and ejaculation pathways

Question 21

What outflow does the sympathetic nervous system have?

Answer 21

Thoraco-lumbar outflow.

Question 22

What outflow does the parasympathetic nervous system have?

Answer 22

Cranio-sacral

Question 23

Which part of adrenal gland is under nervous control?

Answer 23

Medulla

Question 24

Describe somatic efferents

Answer 24

Simplest, efferent neurone terminates directly on effector organ - active to carry out a specific task, inactive the rest of the time, inactive during REM. Fully developed by puberty.

Question 25

What are the functions of the autonomic nervous system?

Answer 25

Life functions: homeostasis, active along with organogenesis, changing continuous output between two ‘opposing’ systems. Intermittent - promotes excretory mechanisms of the body

Question 26

Describe the structure of a peripheral nerve

Answer 26

Single cell axon - endoneureum
Nerve fascicle - perineureum
Entire nerve - endoneureum

Question 27

What do excitatory neurones release?

Answer 27

Glutamate/aspartate neurotransmitters

Question 28

What do inhibitory neurones release?

Answer 28

Glycine/GABA neurotransmitter

Question 29

Where would you find myelinated neurones?

Answer 29

Both the autonomic (CNS) and somatic nervous systems

Question 30

Where would you find unmyelinated neurones?

Answer 30

The autonomic nervous system (Parasymp)

Question 31

Explain the function of the nodes of Ranvier

Answer 31

Allow for saltatory conduction thus making conduction faster.

Question 32

Where is white matter found in a nerve?

Answer 32

Peripherally

Question 33

Where is grey matter found in a nerve?

Answer 33

Peripherally in the shape of a butterfly or figure of H

Question 34

Where are astrocytes found?

Answer 34

Central NS

Question 35

Where are oligodendrocytes found?

Answer 35

Central NS

Question 36

Where are microglia found?

Answer 36

Both the central and peripheral nervous systems

Question 37

Where are Schwann cells found?

Answer 37

PNS