# 5. Spinal cord physiology Flashcards Preview

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Flashcards in # 5. Spinal cord physiology Deck (26):
1

What are the 2 main functions of the spinal cord?

1. propagate nerve impulses (white matter)
2. integrates information (grey matter)

2

What are the 2 main sensory tracts?

1. spinothalamic tract
2. posterior column

3

What does the spinothalamic tract do?

conveys nerve impulses fro sensing pain, termperature, itch, tickle and deep pressure

4

What does the posterior column do?

conveys nerve impulses for touch, light pressure, vibration and conscious proprioception

5

Which to tracts make up the posterior column?

1. gracile fascilicus
2. cuneate fascilicus

6

What is conscious proprioception?

the awareness of the positions and movements of muscles, tendons, and joints

7

what are the 2 main motor tracts?

1. directs pathways
2. indirect pathways

8

What are the direct motor pathways?

-lateral corticospinal tract
-anterior corticospinal tract
-corticobulbar tract

9

What do the direct motor pathways do?

-convey nerve impulses that originate in the cerebral cortex
-causes voluntary movements of skeletal muscles.

10

What are the indirect pathways?

-rubrospinal tract
-tectospinal tract
-vestibulospinal tract
-lateral reticulospinal tract
-medial reticulospinal tract

11

What do the indirect pathways do?

-convey nerve impulses the originate in the brain stem
-cause automatic movements
-muscle tone
-sustain contraction of postural muscles

12

Define stimulus

a change in the internal or external environment

13

Define reflex

a fast involuntary, unplanned sequence of actions that occurs in response to a particular stimulus; can be inborn or learned

14

What are the four types of reflexes?

-spinal reflex
-cranial reflex
-somatic reflex
-autonomic (visceral) reflexes

15

Where does the integration happen in a spinal reflex?

in the grey matter of the spinal cord

16

Where does the integration happen in the cranial reflex?

in the brain stem

17

What is a somatic reflex?

involves contraction of skeletal muscles

18

What are autonomic reflexes?

not usually consciously perceived.
-involves responses of smooth muscle, cardiac muscle and glands.

19

What is a reflex arc (reflex circuit)?

the pathway for a nerve impulse to produce a reflex

20

What makes up the reflex arc? (pg. 462 in new A&P text)

1. sensory receptor
2. sensory neuron
3. integrating center (located in the CNS)
4. motor neuron
5. effector

21

What is a sensory receptor?

-the distal end of a sensory neuron (dendrite) or an associated sensory structure

22

What are the two types of reflex arcs that can occur in the integrating center?

-monosynaptic reflex arc
-polysynaptic reflex arc

23

What is a monosynaptic reflex arc?

-the most simple
-a reflex pathway with only one synapse in the CNS
-involves 2 neurons (the sensory neuron going in and the motor neuron going out) and 1 synapse

24

What is a polysynaptic reflex arc?

-when the integrating center consists of at least one interneuron
-involves more than 1 synapse in the CNS
-involves 3 neurons (one sensory going in, one interneuron to relay message, and one motor neuron going out) and 2 synapses.

25

What is the effector in a reflex arc?

the part of the body that is responding to the nerve impulse
(ie. the muscle or gland)

26

What are the four somatic spinal reflexes?

1. the stretch reflex
2. the tendon reflex
3. the flexor (withdrawal) reflex
4. the crossed extensor reflex