Chapter 4

Question 1

Epidermis

Answer 1

Upper or outermost layer of the two main layers of cells that make up the skin. Mostly made up of dead flat, scale-like cells called squamous cells. Deepest part contains melanocytes, that produce melanin

Question 2

Dermis

Answer 2

Lower or inner layer of the 2 main layers of cells that make up the skin. Contains blood vessels, lymph vessels, hair follicles, and glands that produce sweat. Contains bulk of somatosensory receptors.

Question 3

Somatosensory Perception

Answer 3

3-neuron system that relays sensations detected in the periphery and conveys them via pathways through the spinal cord, brainstem, and thalamic relay nuclei to the. the sensory cortex in the parietal lobe

Question 4

Somatosensory Cortex

Answer 4

Part of the brain that receives and processes sensory information from the entire body

Question 5

Mechanoreceptors

Answer 5

Mechanoreceptors are primary sensory structures that provide information about mechanical features of the internal and external environment

Question 6

Merkel Disk Receptors

Answer 6

Found in the upper layers of skin near the base that has hair and on glabrous skin. Slow adapting, unencapsulated nerve endings, which respond to touch. Receptive fields are small, and with well defined borders that are very sensitive

Question 7

Messinere Corpuscles

Answer 7

Found in the upper dermis, but they project into the epidermis. Found primarily in glabrous skin. They respond to fine touch and pressure, but also to low-frequency vibration. Rapidly adapting fluid filled, encapsulated neurons with small well defined borders responsive to fine details

Question 8

Touch receptive field

Answer 8

Region which a tactile stimulus evoked a sensory response in the cell or the axon

Question 9

Ruffini Corpuscles

Answer 9

Slow adapting, encapsulated mechanoreceptors that detect skin stretch and deformations within joints. Provide valuable feedback for gripping objects and controlling finger position and movement. Also detect warmth and contribute to proprioception and kinesthesia

Question 10

Pacinian Corpuscles

Answer 10

Located deep in the dermis of both glabrous skin and hairy skin. Structure is similar to messiner’s corpuscles. Found in the bone periosteum, joint capsules, pancreas and other viscera, breast, and genitals. Rapidly adapting mechanoreceptors that sense deep transient pressure, and high frequency vibration. Detect pressure and vibration by being compressed which stimulates their internal dendrites

Question 11

Psuedounipolar

Answer 11

A type of neuron which has one extension from its cell body. Contains an axon that has split into 2 branches. One branch PNS, and the other CNS

Question 12

Dorsal Root Ganglion

Answer 12

A cluster of cell bodies in the dorsal root of a spinal nerve. The dorsal root ganglion contain cell bodies for sensory nerves that carry sensory information to the spinal cord

Question 13

Bifurcates

Answer 13

Divide into branches or forks

Question 14

Free Nerve Endings

Answer 14

The terminals of fine unmyelinated fibers or fine, thinly myelinated fibers

Question 15

Transient Receptor Potential Channel

Answer 15

Super family of ion channels occurring in cell membranes that are involved in various types of sensory reception, including thermoreception, chemoreception, mechanoreception, and photoreception.

Question 16

Lateral Spinothalamic tract

Answer 16

Contains fibers from the posterior horn of the spinal cord that carry information regarding pain and temperature to the thalamus

Question 17

The Dorsal Column-Medial Lemniscal Pathway

Answer 17

Carries the sensory modalities of fine touch, vibrations, and proprioception

Question 18

Proprioception

Answer 18

Perception of the position of different parts of the body. It allows you to recognize where your body is positioned in space; the brain uses this information to facilitate movement, maintain balance, and etc.

Question 19

Kinesthesis

Answer 19

The perception of body movements. Being able to detect changes in body position and movements without relying on information from the five senses

Question 20

Sense Modality

Answer 20

A particular way of sensing a stimulus (Via visual system, via auditory system, and etc)

Question 21

Cortical Maps

Answer 21

A neural representation of an input space such that similar features in the input space are represented by neurons which are nearby in the cortex

Question 22

Two-Point discrimination

Answer 22

The ability to discern that two nearby objects touching the skin are truly two distinct points, and not one.