Lab

Question 1

What events occur between striking patellar tendon and leg extension

Answer 1

stimulus: tap to tendon stretches muscle
receptor: muscle spindle stretches and fires
afferent path: action potential travels through sensory neuron
integrating centre: sensory neuron synapses in spinal cord
efferent path 1: somatic motor neuron
effector1: quadriceps muscle
response 1: quadriceps contract, swinging lower leg forward
efferent path 2: interneuron inhibiting somatic motor neuron
effector 2: hamstring muscle
response: hamstring stays relaxed, allowing leg to swing forward

Question 2

An abnormal babinski response may indicate damage to spinal cord. why?

Answer 2

An abnormal babinski reflex is where all the toes still move, but the big toe moves upward, while other toes flex. Since the big toe is still moving, there is no problem with the motor nerve. It indicates damage to the spinal cord at any level because the information is integrated in the brain, rather than in the spinal cord.

Question 3

Which parts of the body have the largest areas of the cortex? Which have the smallest?

Answer 3

Largest: lips, hands, tongue, face
smallest: thigh, back, stomach

Question 4

How does ear transduce sound wave?

Answer 4

1. tympanic membrane vibrates
2. transduction across middle ear bones
3. vibration of oval window
4. fluid wave through vestibular duct
5. wave pushes flexible membranes on cochlear duct, opening ion channels in hair cell. ion flow into hair cell creates electrical signal
6. electrical signals release NTs into the sensory neurons
7. triggers action potential that transport through cochlear nerve to brain
8. energy from waves transfers across cochlear duct, into tympanic duct, and is dissipated back into middle ear at the round window

Question 5

How will a severe middle ear infection affect Rinne’s test?

Answer 5

An ear infection would affect sound transduction through the middle ear, indicating conductive hearing loss. in air vs bone, the sound should transfer through better through the air. with an ear infection, the sound will be greater through bone.

Question 6

What senses are affected by lateral inhibition? Briefly explanation lateral inhibition.

Answer 6

-vision
-tactile (touch)
-auditory
lateral inhibition enhances the contrast between centre of receptive field and edges of receptive field.