Spinal Cord physiology

Question 0

Two major sensory tracts:

Answer 0

1. Spinothalamic tract

2. Posterior column

Question 1

Two functions of the spinal cord:

Answer 1

1. Propagates nerve impulses (in white matter)

2. Integrates information (in grey matter)

Question 2

Spinothalamic tract

Answer 2

One of the two main sensory tracts.

Conveys nerve impulses for sending pain, temperature, itching, tickling, deep pressure and crude touch.

Question 3

Posterior column

Answer 3

One of the two main sensory tracts. (Most of sensory tract)

Discriminative touch. Light pressure, vibrations, conscious proprioception.

Question 4

Conscious proprioception

Answer 4

Awareness of positions and movements of your muscles, tendons and joints.

Question 5

Posterior column is made up of what two tracts:

Answer 5

Gracile fasciculus

Cuneate fasciculus

Question 6

Two main motor tracts

Answer 6

1. Direct pathway (intrapyramidal)

2. Indirect pathways (extrapyramidal)

Question 7

Direct motor pathway

Answer 7

Nerve impulses originates in cerebral cortex.

Voluntary movements of skeletal muscle.

Question 8

Indirect motor pathways

Answer 8

Extrapyramidal

Nerve impulses originate in brain stem.
Causes automatic movements.
Helps coordinate movement with visual stimuli.
Maintains skeletal muscle tone
Sustains contraction of postural muscles
Maintain equilibrium by regulating muscle response to head movement.

Question 9

Reflex

Answer 9

Fast, involuntary and unplanned sequence of actions that occurs in response to a particular stimulus.

Question 10

Spinal reflex

Answer 10

Integration in grey matter of spinal cord

Question 11

Cranial reflex

Answer 11

Integration in brain stem

Question 12

Somatic reflex

Answer 12

Involves contraction of skeletal muscle.

Question 13

Autonomic reflex

Answer 13

AKA visceral reflex

Not usually consciously perceived.
Smooth or cardiac muscle, glands.

Question 14

Five (ish) components of a reflex arc

Answer 14

1. Sensory receptor
2. Sensory neuron
3. Integrating centre
4. Motor neuron
5. Effector.

Question 15

What is the only monosynaptic reflex arc?

Answer 15

Stretch reflex.

Question 16

What is the only contralateral reflex?

Answer 16

Crossed extensor reflex

Question 17

Intersegmental Reflex Arc

Answer 17

A single sensory neuron activates a number of motor neurons, at different segments of the spinal cord.

Question 18

Reciprocal inhibition/innervation

Answer 18

Sensory neuron from GTO synapses with excitatory interneuron, which synapses with motor neuron in antagonistic muscle.

Question 19

Stretch reflex

Answer 19

Contraction of skeletal muscle in response to stretch. Prevents over stretching.

Monosynaptic
Ipsilateral.

1. Muscle spindles
2. Posterior nerve root
3. In spinal cord, synapses with motor neuron in anterior gray horn
4. Motor neuron
5. Muscle contracts.

Question 20

Muscle tone

Answer 20

Degree of contraction when muscle is at rest.

Set my muscle spindle.

Question 21

Tendon reflex

Answer 21

Relaxation of muscle when under too much tension.

Ipsilateral
Polysynaptic

1. GTO stimulated by tension in tenson
2. Nerve impulses to SC
3. Activates inhibitory interneuron what synapses with motor neuron
4. Motor neuron inhibited
5. Muscle relaxes.

Question 22

Flexor/Withdrawl reflex

Answer 22

Pain Withdrawl response.

Polysynaptic
Ipsilateral
Intersegmental

1. Sensory receptor or pain sensitive neuron
2. Nerve impulses to SC
3. Activates interneuron that extend to several SC segments
4. Several motor neurons activated
5. Relevant muscles contract

Question 23

Crossed Extensor Reflex

Answer 23

Occurs with flexor/Withdrawl reflex. Compensatory balance

Contralateral
Polysynaptic
Intersegmental

1. Pain sensitive neuron
2. Sensory neuron impulse to SC
3. Activation of several interneuron a
4. Excited motor neurons to muscles on unaffected side
5. Contraction of opposite side muscles.