Topic 6

Question 1

Structure of a pacinian corpuscle

Answer 1

Neurone ending surrounded by layers of connective tissue which are separated by a viscous gel
Contained within a capsule
Stretch mediated sodium ion channels on the membrane

Question 2

How does a pacinian corpuscle respond to pressure?

Answer 2

Pressure deforms membranes, causes the stretch mediated Na+ channels to open.
Na+ diffuse into the sensory neurone
This creates a generator potential
Depolarisation

Question 3

Name the 2 photo receptor cells in the retina

Answer 3

Cone cells
Rod cells

Question 4

Where are cone and rod cells located?

Answer 4

Cone - mainly at the fovea
Rod -evenly distributed at the retina, NOT at the fovea

Question 5

Compare and contrast rod and cone cells

Answer 5

Cone cells -
• pigment is iodopsin, high visual acuity, one cone cell with one bipolar cell, has 3 colours (red, green and blue), therefore see colour
Rod cells -
• pigment is Rod, low visual acuity, black and white, many rod cells with one bipolar cell (spatial summation)