Spinal cord tracts

Question 1

How is the nervous system organised?

Answer 1

Into the Central and Peripheral nervous system

Question 2

What are afferent somatic (sensory) nerves

Answer 2

nerves that come from the skin/ retina

Question 3

What are afferent visceral (sensory) nerves?

Answer 3

nerves that come from thoracic/ abdominal areas

Question 4

What are efferent somatic (motor) nerves?

Answer 4

Nerves that go towards skeletal muscle

Question 5

What are efferent visceral (motor nerves)?

Answer 5

Nerves that go towards cardiac muscle

Question 6

What is a reflex?

Answer 6

an inherent, subconscious, relatively consistent response to a particular stimulus

Question 7

What are exteroreceptors?

Answer 7

Receptors that receive input from outside the body, e.g olfactory, smell and sight

Question 8

What are interoreceptors?

Answer 8

Receptors that receive input from inside of the body/ internal environment

Question 9

What are proprioreceptors?

Answer 9

Receptors used in spatial orientation/ mechanical so limbs etc.

Question 10

What are the main functions of the motor system?

Answer 10

to maintain posture, gait and provide a stable platform for movement

Question 11

Where are UMN found?

Answer 11

they are completely contained within the central nervous system and usually located in the brain stem or the forebrain

Question 12

What is the function of UMN?

Answer 12

modify and regulate the activity of LMN

Question 13

Where are LMN found?

Answer 13

their cell body is in the CNS and their axons project into the PNS via cranial or spinal nerves

Question 14

What is an ascending pathway?

Answer 14

They carry information from the receptors to the brain

Question 15

What is a descending pathway?

Answer 15

Carries information from the brain to effectors via the spinal cord

Question 16

What are tracts and where are they found?

Answer 16

Tracts are a bunch of functionally related axons found in the CNS (white matter)

Question 17

What is the first order neuron?

Answer 17

spinal ganglion

Question 18

What is the second order neuron?

Answer 18

In the spinal cord

Question 19

What is the third order neuron?

Answer 19

thalamus

Question 20

What is the somatosensory cortex?

Answer 20

Area where pain is localised

Question 21

What is the Spinocervicothalamic tract?

Answer 21

Concerned with the transmission of superficial pain and tactile sensations considered primary conscious pathway in carnivores

Question 22

What are the four extrapyramidal spinal pathways?

Answer 22

Rubrospinal, Vestibulospinal, Reticulospinal, and Tectospinal

Question 23

Which pathways control involuntary movement and adjustment of posture?

Answer 23

Vestibulospinal, Reticulospinal and Tectospinal

Question 24

Which spinal pathway controls voluntary movements?

Answer 24

Rubrospinal pathway

Question 25

Explain the patellar reflex

Answer 25

Tapping the patellar tendon activates the receptors in the quadriceps muscle, this then sends an impulse through the afferent sensory nerve to the spinal cord
Efferent motor nerve (femoral nerve) then extends/contracts the quadricep muscle whilst simultaneously inhibiting the hamstring from flexing

Question 26

Where does the motor component of the femoral nerve arise from?

Answer 26

L4-L6

Question 27

What nerve does the withdrawal reflex primarily test for?

Answer 27

Tests primarily for the sciatic nerve and the spinal cord

Question 28

What are the two pathways motor systems are functionally grouped into?

Answer 28

Ventromedial motor system and the Dorsolateral motor system

Question 29

What is the ventromedial motor system?

Answer 29

axial and proximal limb muscles, especially extensors

Question 30

What type of reflex is the patellar reflex?

Answer 30

It is a type of myotatic reflex

Question 31

Describe the spinothalamic tract

Answer 31

1) Receives pain stimulation from nociceptors
2) Pain stimulation travels to the first order neuron in the dorsal horn
3) neuron decussates to the other side to reach the second order neuron which then ascends along the tract
4) Third order neurons in the thalamus receive the stimulation and carry the impulse to the somatesthetic area of the cerebral cortex

Question 32

What are the two types of spinothalamic tract?

Answer 32

tract that goes to the lateral thalamus (neurons that decussate) = intensity of the pain
tract that goes to the medial thalamus (neurons that do not decussate) = emotional aspects of pain

Question 33

In what area of the dorsal horn are most of the projection neurons concentrated (for the spinothalamic tract)

Answer 33

Marginal nucleus and nucleus proprius

Question 34

What is the difference between spinothalamic and spinocervicothalamic?

Answer 34

Spinocervicothalamic is mostly concerned with carnivores
And has a 4th order neuron

Question 35

Describe the spinocervicothalamic pathway

Answer 35

1) Pain sensation from nociceptors along 1st order neuron
2) reaches the second order neuron on the marginal nucleus/ nucleus proprius which then ascends ipsilaterally
3) Terminates with the 3rd order neurons on the lateral cervical nucleus which then decussate to terminate on the 4th order neurons at the contralateral thalamus
4) these axons then project to the cerebral cortex

Question 36

In what segment is the lateral cervical nucleus found?

Answer 36

C1, C2

Question 37

What 4 pathways are knowns as extrapyramidal and why?

Answer 37

Rubrospinal, Reticulospinal, Tectospinal and vestibular spinal
because they pass outside of the ventral pyramids in the medulla