Lecture 2 - Receptors

Question 1

Free Nerve endings

Answer 1

Mostly unmyelinated have small sensory terminals that act as cation channels that respond to temperature, pain, movement, pressure.
Some wrap-around hair follicles and act as light touch receptors

Question 2

Tactile discs

Answer 2

Free nerve endings which are located in the deepest layer of the epidermis. They are abundant in the fingertips and have large disc-shaped epidermal (Merkel) cells. Sensitive to texture, shapes and edges.

Question 3

Tactile corpuscles

Answer 3

Located in the papillary layer of the dermis. They are unmyelinated sensory terminals surrounded by modified schwann cells and a thin oval of fibrous connective tissue. They detect fine touch, deep pressure and low frequency

Question 4

What does deformation of the capsule in tactile corpuscles trigger?

Answer 4

The entry of Na+ ions into the nerve terminal

Question 5

Lamellar corpuscles

Answer 5

Scattered deep in the dermis and hypodermis. Dendrite lying in layers of collagen and fibroblasts. Deformation of the capsule opens pressure sensitive Na+ channels in sensory axon.

Question 6

Bulbous corpuscles

Answer 6

Located in the dermis and subcutaneous tissue. Also found in joint capsules. Network of free nerve endings twisted with a core of collagen fibres. Capsule surrounds the entire structure