CH8 Part 1

Question 1

Myelin Sheath

Answer 1

Composed of Schwann Cells in PNS, Oligodendrocytes in CNS.

Question 2

Glial Cells

Answer 2

Schwann Cells

Oligodendrocytes

Astrocytes - guid neural development; synaptic communication regulation; regulate nuerotransmitter levels

Microglia - remove dead cells/debris

Ependymal Cells - Produce and circulate CSF

Question 3

Nernst Equation

Answer 3

E(ion) = (RT/zF)ln[Xout]/[Xin]

Note that Na Eq potential is +50 mV

K eq is about -90 mV, makes sense as most leak channels are K leak channels meaning the cell tends toward -90 mV

Question 4

Enzyme that degrades ACh in the neuromuscular junction

Answer 4

Acetylcholinesterase (AChE)

Question 5

Grey Matter in different locations of nervous system

Answer 5

Nucleus - deep in brain

Cortex - surface of brain

Horn - spinal cord

Ganglion - PNS

Question 6

Medulla

Answer 6

Or Medulla oblongata

Relays messaging to other parts of brain.

BP, respiratory rythmicity, digestive functions (vomiting)

Question 7

Pons

Answer 7

Connection between brain stem and cerebellum.

Balance and anti-gravity posture.

Some autonomic functions.

Question 8

Brainstem

Answer 8

Medulla, pons, midbrain

Question 9

Midbrain

Answer 9

Relay for visual and auditory info. Contains much of Reticular Activating System (RAS)

Question 10

Forebrain Components

Answer 10

Diencephalon, telencephalon

Question 11

Diencephalon

Answer 11

Thalamus - relay and processing system for sensory information.

Hypothalamus - emotion control and autonomic functions; hormone production and risk.

Question 12

Telencephalon

Answer 12

Forms two cerebral hemispheres (distinct to previous hindbrain and midbrain - one stalk), the cerebrum.

Hemispheres
Cerebrum

Question 13

Lobes

Answer 13

Frontal Lobe - voluntary movement/complex reasoning

Parietal lobes - general sensations (touch temperature digestion etc.)

Temporal Lobes - auditory and olfactor sensation; short-term memory and language comprehension; emotion

Occipital lobe - visual info

Question 14

Basal nuclei

Answer 14

Deep in brain.

Voluntary movement and procedural learning habits.

Inhibitory, so works in concert with the cerebellum.

Question 15

Limbic

Answer 15

Between cerebrum and diencephalon

Question 16

How many nerves entering CNS?

Answer 16

12 Paired Cranial Nerves

31 pairs of Spinal nerves

Question 17

Somatic PNS Anatomy

Answer 17

Somatic motor neurons innervate skeletal muslce and use ACH. Cell bodies in brain stem or ventral spinal cord.

All somatic sensory neurons have long dendrite from receptor toward soma which is just outside CNS in a dorsal root ganglion.

Note: Dorsal root ganglia are outside the meninges of the spinal cord and brain.

Question 18

Autonomic PNS anatomy

Answer 18

Pre-ganglionic neuron: cell body in brain stem or spinal cord. All release ACh.

Post-ganglionic neuron: synapse in ganglion from preganglionic neuron. All parasympathetic release ACh. Most sympathetic release norepinephrine. Synapse on an effector (visceral organs).

Question 19

Sympathetic efferent pre-ganglionic efferents

Answer 19

All have cell bodies in thoracic or lumbar regions of spinal cord. (Thoracic-lumbar system)

pre-ganglionic axon is quite short. Few ganglia that are large. Post-ganglionic axons are large and project to an effector.

Question 20

Parasympathetic efferent preganglionic neurons

Answer 20

Cell bodies in brainstem or in sacral portion of spinal cord. (craniosacral system)

preganglionic neurons project long axon to small ganglion located close to effector.

Postganglionic axon is quite short.

Question 21

Autonomic v. Somatic afferents (sensory)

Answer 21

Autonomic, they can synapse