Neuro 5

Question 1

a sensory receptor either…

Answer 1

Either
• Specialized cells that send a chemical signal to the sensory neuron, or
• Specialized terminals of the sensory neuron

• Excitation or inhibition are typically the result of ion channels opening or closing

Question 2

what are the 5 sensory receptor types

Answer 2

1. mechanoreceptors - touch, vibration
2. photoreceptors - light
3. nociceptors - tissue damage
4. chemoreceptors - chem.
5. thermoreceptors -temp

Question 3

sensory receptors play a…

Answer 3

homeostatic role

responding to food, light, chemicals, blood pressure etc.

Question 4

Ear hair cell example

Answer 4

hair cells - line the cochlea
- vibration of the ear drum moves the cilia to open/close K+ channels - depolarizing nerve cells and sending a message

Question 5

How to tell the dorsal and ventral side of a spinal cord

Answer 5

ventral side has long ventral medial fissure
dorsal side has a smaller dorsal medial sulcus and 2 dorsolateral sulci

Question 6

3 parts of white matter in the spinal cord

Answer 6

dorsal, lateral, and ventral funiculus

Question 7

how to tell the difference between cervical, thoracic, and lumbar spinal cord

Answer 7

C- more white matter than gray (small butterfly and deep ventral median fissure)

T- intermediolateral horn for sympathetic motor neurons (deep dorsolateral sulcus and overall rounded appearance)

L- more gray than white matter

Question 8

Sensory pathways are mostly on the

Answer 8

dorsal side (and dorsal funiculus)

Question 9

motor pathways are mostly on the…

Answer 9

ventral side and ventral funiculus

Question 10

Dorsal somatosensory pathways is also called the…. and is a __#__ neuron pathway

Answer 10

dorsal column system (touch, position, vibration)

three!

Question 11

Where are the three neurons in the dorsal somatosensory pathway?

Answer 11

First neuron
• Cell body in dorsal root ganglion
• Axon ascends in dorsal funiculus
• Synapses in brainstem (medulla)

Second neuron
• Cell body in medulla
• Axon crosses midline !!!!
• Synapses in thalamus

Third neuron
• Cell body in thalamus
• Synapses in sensory cortex

Question 12

Lateral somatosensory pathway is also called the…. and is a __#__ neuron pathway

Answer 12

spinothalamic tract (pain and temperature)

Three!!

Question 13

What is the neuron pathway of the lateral somatosensory pathway

Answer 13

First neuron
• Cell body in dorsal root ganglion
• Synapses in dorsal horn of spinal cord

Second neuron
• Cell body in dorsal horn of spinal cord
• Axon crosses midline !!!!!!
• Ascends in lateral funiculus
• Synapses in thalamus

Third neuron
• Cell body in thalamus
• Synapses in sensory cortex

Question 14

what are the pyramids

Answer 14

external landmark on the ventral medulla

corresponds to tracts composed of axons from the motor cortex to the spinal cord

Question 15

How many neurons are in the lateral corticospinal tracts and what is its purpose

Answer 15

two - voluntary control of skeletal muscle in distal limbs

Question 16

What is the neuron pathway for the lateral corticospional tract

Answer 16

(goes from the brain down)

Upper motor neuron
• Cell body in primary motor cortex
• Axon crosses midline in the ventral medulla (pyramids) !!!!
• Axon descends in the lateral corticospinal tract
• Synapses in ventral horn

Lower motor neuron
• Cell body in ventral horn
• Innervates skeletal muscle

Question 17

How many neurons are in the ventral corticospinal tracts and what is its purpose

Answer 17

two!

voluntary control of skeletal muscle in proximal limbs and trunk

Question 18

Explain the neuron pathway for the corticospinal tract

Answer 18

(from the brain down)
Upper motor neuron
• Cell body in primary motor cortex
• Axon passes through the ventral medulla (pyramids) and descends in the ventral corticospinal tract
• Axon crosses midline at the level of the second neuron !!!!
• Synapses in ventral horn

Lower motor neuron
• Cell body in ventral horn
• Innervates skeletal muscle

Question 19

What is the extrapyramidal tracts

Answer 19

Motor pathways other than the corticospinal tracts
• Axons do not travel in the pyramids of the medulla

Question 20

what are the functions of the extrapyramidal tracts

Answer 20

• Alternative route of transmission from motor cortex to spinal cord
• Control of postural reflexes
• Control of eye movements
• Control of head movements in response to sound or light
• Regulate muscle tone

Question 21

What is a neuromuscular junction

Answer 21

Synapse between a motor neuron and a muscle cell

Question 22

How does the neuromuscular junction work in the somatic nervous system?

Answer 22

• Neurotransmitter = acetylcholine
• Receptors = nicotinic cholinergic
• Response to binding = channel opens and Na+ flows into cell
• Depolarization
• Calcium released from endoplasmic (sarcoplasmic) reticulum
• Calcium promotes muscle contraction

Question 23

Processes involved in consciousness

Answer 23

Depends on multiple CNS structures
• Association cortex
• Ascending reticular activating system
• Thalamus
• Hypothalamus
• Midbrain
• Pons
• Medulla

Question 24

processes involved in memory

Answer 24

• Hippocampus is important in memory formation
• Memory storage is distributed throughout the cerebral cortex
• Learning = strengthening of synapses between neurons

Question 25

Intervertebral Disc Disease

Answer 25

nucleus of the disc bursts into the spinal cord space and damages nerve root