SENSING&RESPONDING: reflexes

Question 1

define disynaptic reflex arc

Answer 1

2 interconnections between the sensory neuron & interneuron and motor neuron & interneuron

Question 1

define reflex arc

Answer 1

the basic neural pathway linking a sensory receptor to a muscle
- sensory neuron innervates receptor
- motor neuron innervates muscle
- connected by interneurons

Question 2

define spinal reflex

Answer 2

a reflex with a neural circuitry confined to the spinal cord and body, not involving the brain

Question 3

describe the monosynaptic muscle stretch reflex (phasic muscle stretch reflex)

Answer 3

eliciting stimulus = stretching of skeletal muscle
response = muscle contraction
- possessed by all skeletal muscles

Question 4

describe the knee jerk response

Answer 4

patellar tendon moves in, patellar down, quad muscle pulled, receptors stimulated

Question 5

define muscle spindles

Answer 5

receptor organs in the muscles, found in almost all skeletal muscles

Question 6

3 components of muscle spindles

Answer 6

• muscle stretch receptors
• fibrous capusle
• primary endings
• secondary endings

Question 7

describe the fibrous capsule of muscle spindle

Answer 7

• intrafusal muscle fibres
• connective tissue
• sensory / motor neuron endings

Question 8

describe the primary endings

Answer 8

type 1a afferent
- responsive to speed of muscle lengthening
- fast adapting
- response of muscle contraction depends on stretch of muscle

Question 9

describe the secondary endings

Answer 9

type 2 afferent endings
- responsive to amount of muscle stretch
- slow adapting

Question 10

what is the eliciting stimulus in the frog wiping reflex?

Answer 10

irritation at a location on the skin

Question 11

what is the response in the frog wiping reflex?

Answer 11

movement involving extension of rear leg wiping the toes over the stimulus

Question 12

describe the leg movement response in the frog wiping reflex

Answer 12

• positions leg so foot is in correct position to stimulus location, depending on the position of the forelimb
• hind limb must know where forelimb is
• spinal cord knows where limbs and stimulus are

Question 13

what does it mean if a reflex response is not stereotyped?

Answer 13

the same outcome is able to be achieved under different circumstances

Question 14

what are the extra ocular muscles?

Answer 14

muscles which produce eye movement in the eye socket

Question 15

what produces horizontal eye movements?

Answer 15

contracting medial and lateral recti