Lecture 1 NS - Introduction to Neuro

Question 1

What is the central nervous system comprised of?

Answer 1

Brain and spinal cord

Question 2

What is the PNS comprised of?

Answer 2

Nerves and ganglia outside brain and spinal cord

Question 3

What are the divisions of the PNS?

Answer 3

Autonomic and somatic

Question 4

What does the somatic PNS do?

Answer 4

Controls motor and sensory function for the body wall - skin and skeletal muscle

Question 5

What does the autonomic NS do?

Answer 5

Regulates viscera: internal organs, smooth muscle, pupils, sweating, blood vessels, bladder, intestine, glands and controls heart contraction rate

Question 6

What are the 2 subtypes of autonomic NS?

Answer 6

Sympathetic and parasympathetic

Question 7

In which direction does the information flow in the NS?

Answer 7

Axons enter and leave the CNS through pairs of spinal nerves and cranial nerves

Question 8

What are afferent axons?

Answer 8

They propagate AP TOWARDS CNS from PNS SENSORY

Question 9

What are efferent axons?

Answer 9

Propagate AP FROM CNS to PNS MOTOR

Question 10

What are interneurons?

Answer 10

CNS neurons that synapse with other CNS neurons within the brain/spinal cord

Question 11

What are the ways that information flows through the NS?

Answer 11

AP generation/propagation Synaptic transmission Nerve conduction

Question 12

What does the cerebral cortex do and what does it look like?

Answer 12

2 hemispheres, each receives sensory info from and controls movement of opposite side of body

Question 13

What does the cerebellum do?

Answer 13

Controls coordination of movement

Question 14

What does the brain stem do?

Answer 14

Most primitive part w/densely packed fibres Regulates vital functions and damage here can be fatal

Question 15

What is the anatomy of the spinal cord? Fill in the blanks

Answer 15

Question 16

Where does the CNS end?

Answer 16

At the margins of the spinal cord

Question 17

What emerges from the spinal cord?

Answer 17

Dorsal and ventral roots - part of PNS

Question 18

How are axons packed into nerves?

Answer 18

Spinal nerves contain both afferent and efferent axons, bundled into fascicles surrounded by perineurium, with a tough epineurium capsule Individual axons are also wrapped w/myelin and endoneurium, though some are unmyelinated

Question 19

What is the anatomy of a nerve (with axons inside)? Fill in the blanks

Answer 19

Question 20

What is the function of a neuron?

Answer 20

Transmit and receive AP, or stimulate target tissue

Question 21

What is the anatomy of a nerve cell? Fill in the blanks

Answer 21

Question 22

How does regeneration differ between PNS and CNS?

Answer 22

PNS: axons can regenerate after injury, CNS axons are unable to regenerate over long enough distances to be useful

Question 23

What is a compromise that can occur during PNS regeneration?

Answer 23

Aberrant axon sprouting and non-specific target reinnervation - can lead to neuropathic pain

Question 24

Why can’t CNS neurons regenerate?

Answer 24

There are inhibitory molecules in CNS (myelin differences), absence of guidance cues that stimulate axon growth during development and some loss of intrinsic axon growth capacity by neurons

Question 25

What is the grey matter comprised of?

Answer 25

Neuronal cell bodies

Question 26

What is the white matter comprised of?

Answer 26

Ascending and descending axon tracts to and from the brain

Question 27

Which type of neuron is each one?

Answer 27

Question 28

What types of inputs and outputs are required for a reflex response?

Answer 28

Somatic sensory inputs to interneurons then motor outputs from spinal cord

Question 29

What does a reflex response require?

Answer 29

Sensory and motor neurons to be intact between periphery and spinal cord

Question 30

What type of input/output is needed for conscious registering of sensory stimulus?

Answer 30

Sensory input activates sensory neurons in spinal cord grey matter that transmit AP upwards to sensory cortex of brain - then neurons in motor cortex of brain extend axons downward to synapse with the spinal motor neurons and transmit AP for voluntary movement

Question 31

What do A, B, C, D form and what are they?

Answer 31

Neurons A-D form the motor pathways controlling voluntary movement, C/D are motor neurons in spinal cord which innervate skeletal muscle to stimulate contraction directly A/B are cortical neurons in motor cortex which activate spinal cord motor neurons C/D respectively

Question 32

What do somatic sensory neurons do?

Answer 32

Convey sensory information from the body to the spinal cord and from there to the sensory cortex where sensation is perceived - stimulate reflex activity via spinal cord motor neurons and activate spinal cord sensory neurons which relay signals to the brain

Question 33

What are E and F?

Answer 33

Single neurons which represent the sensory pathways for the limbs in the dorsal root ganglia - depicted as synapsing with a motor neurone in both spinal cord and motor cortex