reflexes

Question 1

What kind of reflex is the knee-jerk reflex?

Answer 1

• spinal

Question 2

How does the knee-jerk reflex work?

Answer 2

• Leg tapped below patella
• Patellar tendon stretched (stimulus)
• Stretch receptors detect stimulus and send impulse along sensory neurone.
• Impulse transmitted across synapse to relay neurone in SC
• Relay neurone transmits it across synapse to motor neurone
• Motor neurone transmits impulse to extensor muscle at top of thigh to contract.
• At the same time, a relay neurone inhibits the motor neurone at the flexor muscle, causing it to relax.

Question 3

What stimuli can trigger the blinking reflex?

Answer 3

• Loud noises
• Touch (corneal reflex)
• Bright light (optical reflex)

Question 4

Is the blinking reflex cranial or spinal?

Answer 4

• cranial

Question 5

Where is the relay neurone involved in the blinking reflex found?

Answer 5

• lower brain stem

Question 6

Why is the blinking reflex described as a consensual response?

Answer 6

• both eyes close

Question 6

Why are reflexes important?

Answer 6

• Innate (do not have to be learnt)
• Involuntary (no decision making required as decision making parts of the brain not involved)
• ## Extremely fast (short reflex arc; one or two synapses)