reflexes

Question 1

what is the function of the spinal cord?

Answer 1

neuronal link between brain and PNS
integrating centre for spinal reflexes

Question 2

how many pairs of spinal nerves are there?

Answer 2

31

Question 3

how many cervical nerves?

Answer 3

8

Question 4

how many thoracic nerves?

Answer 4

12

Question 5

how many lumbar nerves?

Answer 5

5

Question 6

how many sacral nerves?

Answer 6

5

Question 7

how many coccygeal nerves?

Answer 7

1

Question 8

how are spinal nerves connected to the spinal cord?

Answer 8

dorsal root (gains signal)
ventral root (sends signal)

Question 9

what connects the dorsal and ventral roots?

Answer 9

interneuron

Question 10

what are nerve tracts? and what are the 2 types?

Answer 10

white matter organized into bundles of nerve fibers with a similar function.
ascending and descending

Question 11

what does the dorsal horn contain?

Answer 11

cell bodies of interneurons on which afferen tneurons terminate

Question 12

what do lateral horns contain?

Answer 12

cell bodies of autonomic efferent nerve fibers

Question 13

what do ventral horns contain?

Answer 13

cell bodies of somatic efferent neurons

Question 14

what is a reflex?

Answer 14

an involuntary response to sensory input

Question 15

what are the 2 types of reflexes?

Answer 15

simple and conditioned

Question 16

what is a somatic reflex and what does it involve?

Answer 16

somatic neurons and skeletal muscles
spinal and cranial

Question 17

what is a autonomic/visceral reflex and what does it involve?

Answer 17

autonommic neurons
spinal - urination/defecation
brain - gag, vomit, sneeze, cough, swallow

Question 18

what are the 5 characteristics of a reflex pathway?

Answer 18

sensory receptor
afferent pathway
integrating center
efferent pathway
effector

Question 19

what is a monosynaptic reflec and what is one example?

Answer 19

a single synapse between the afferent and efferent neurons
strecth/knee-jerk

Question 20

what is a polysynaptic reflex and what is one example?

Answer 20

2 or more synapses between afferent and efferent neurons
flexion

Question 21

what is the function of a muscle spindle and where is it located?

Answer 21

senses stretch
located in muscles

Question 22

what type of contraction does a muscle spindle perform?

Answer 22

isotonic contraction

Question 23

what is the relationship between tension and length for a muscle spindle?

Answer 23

length changes but tension is constant

Question 24

what is the purpose of the golgi tendon organ and where is it located?

Answer 24

senses force
located in tendons

Question 25

what type of contraction is associated with the golgi tendon organ?

Answer 25

isometric contraction

Question 26

what is the relationship between tension and length in the golgi tendon organ?

Answer 26

tension increases, length is constant

Question 27

what is the purpose of the joint receptor?

Answer 27

senses pressure and position

Question 28

what does a gamma-motor neuron do?

Answer 28

modulate sensitivity of the spindles

Question 29

what causes a lack of reflex?

Answer 29

interruption of reflex arc via peripheral sensory or lower neuron
muscle disease

Question 30

what causes an increased reflex and muscle tension?

Answer 30

injury to upper motor neurons

Question 31

_____ is the afferent component of the muscle reflex

Answer 31

sensory neuron