Senses And Perceptions 2

Question 1

What are the receptor endings on the peripheral of the skin

Answer 1

Free nerve endings
They are unspecialised

Question 2

Give some examples of mechanoreceptors

Answer 2

• meissners corpuscle
• meckels disc
• hair follicle receptors
• pacunian corpuscle
• ruffini endings

Question 3

Describe peripheral nerve structure

Answer 3

Contain sensory neurons (afferents) and motor neurons (efferents)

Question 4

What is epineurium

Answer 4

Tough connective tissue provides mechanical protection, covers each individual fascicle in peripheral nerves

Question 5

What is a fascicle

Answer 5

Each individual axon

Question 6

What surrounds the peripheral nerve

Answer 6

Perineurium

Question 7

Describe the vascular supply for peripheral nerves

Answer 7

Many blood vessels requires an adequate blood supply

Question 8

Describe alpha axons

Answer 8

Diameter - 13-20 (um)
Speed - 80-120 (m/sec)
Sensory receptors - proprioceptors of skeletal muscle

Conduct very fast

Question 9

Describe beta axons

Answer 9

• diameter 6-12 (um)
• speed - 35-75 (m/sec)
• sensory receptors - mechanoreceptors of skin

Conduct action potentials fats but not as fast as alpha

Question 10

Describe delta axons

Answer 10

Thin myelin sheath
The action potential moves slowly
5-30m/sec
Pain temperature

Question 11

Describe the C axon

Answer 11

Unmyelinated
0.5m/sec
Temperature, pain, itch

Question 12

What brain matter is in the centre of the brain

Answer 12

Central is grey matter

Question 13

What matter is found on the outside of the spinal cord

Answer 13

White matter

Question 14

What are sensory afferents

Answer 14

The sensory nerve that travels from the stimuli to the dorsal horn

Question 15

What are the motor efferents

Answer 15

The motor stimuli from the ventral horn to the muscle

Question 16

What goes into the spinal cord

Answer 16

Sensory afferents

Question 17

What comes out of the spinal cord

Answer 17

Motor efferents

Question 18

What is the dermatome map

Answer 18

The map of the skin, what parts of the skin is innervated by which part of the spinal cord

Question 19

What are the branches of the trigeminal nerve

Answer 19

Opthalmic and maxillary - sensory branches
Mandibular - mixed sensory and motor

Question 20

Where is the receptive field represented

Answer 20

In the cortex

Question 21

What body regions have high cortical representation

Answer 21

Body regions with high sensory innervation (high density of receptor endings and small overlapping receptive fields) have greater cortical representation

Question 22

What is the dorsal root

Answer 22

The dorsal root ganglia to the dorsal horn

Question 23

What are the sensory branches of the trigeminal nerve

Answer 23

Ophthalmic and maxillary branch

Question 24

What is the mixed sensory and motor region of the trigeminal nerve

Answer 24

Mandibular branch

Question 25

What neurons are involved in the sensory pathway

Answer 25

Neuron 1- primary sensory neuron (periphery) Neuron 2 - secondary sensory neuron (spinal cord/brainstem) Neuron 3- tertiary sensory neuron (thalamus)

Question 26

Describe the mechanosenation pathway

Answer 26

Neuron 1 - from hand (stimulus) to medulla (brainstem) Neuron 2 - at medulla switches to the other side and goes to the thalamus Neuron 3 - synapses at the second neuron and sends information to the cortex, where the mapping of the body is

Question 27

Describe the nociception pathway

Answer 27

Neuron 1 - stimulates pain receptor, pain synapses when it enters the spinal cord rather than at the medulla, meaning it switches sides here Neuron 2- bypasses the brainstem, must go to the thalamus and synapses with the 3rd neuron here Neuron 3 - travels to the cortex and gains a response, this is where you will become aware of the pain

Question 28

What is the spinal nucleus

Answer 28

Sensory tract located in the lateral medulla, principle function id relaying temp and sensation to the face