PH1124 - Skin & the integument system

Question 1

What are the 3 layers of the skin?

Answer 1

epidermis, dermis, hypodermis (subcutaneous layer)

Question 2

What are the 3 main cells in the epidermis?

Answer 2

Keratinocyte, Melanocyte, langerhans

Question 3

What is the function of a Keratinocyte?

Answer 3

Dynamic renewal and differentiation.

The main purpose of these keratin-producing cells is to preserve against microbial, viral, fungal and parasitic invasion; to protect against UV radiation; and to minimize heat, solute and water loss.

Question 4

What is the function of an melanocyte?

Answer 4

Contribute to skin colour, filter UV light.

Question 5

What is the function of Langerhans?

Answer 5

Immune surveillance, they are dendritic antigen presenting cells.

Question 6

What are the main cells in the dermis?

Answer 6

Fibroblast and Dendritic cells.

Question 7

What is the function of a fibroblast?

Answer 7

Produces collagen to make fibres.

Question 8

What is the function of dendritic cells?

Answer 8

Antigen producing cells so involved in immune surveillance.

Question 9

What are the 2 different layers in the epidermis?

Answer 9

The proliferating layer and the differentiating layer.

Question 10

What are the 2 layers that make up the proliferating layer?

Answer 10

The stratum basale and the lamina basale.

Question 11

What are the 3 layers that make up the differentiating layer?

Answer 11

Stratum corneum, stratum granulosum and the stratum spinosum.

Question 12

What processes start to happen in the stratum granulosum?

Answer 12

Lipid extrusion, cornification (Formation of cornified envelopes)

Question 13

What is desquamation?

Answer 13

Shedding off of dead skin cells

Question 14

How is psoriasis caused?

Answer 14

Autoimmune disease where there is an increased in oxidised lipids that causes hyperproliferation of keratinocytes.

Question 15

How is eczema caused?

Answer 15

Alteration in the ceramide species that causes a perturbed barrier causing inflammation and infection.

Question 16

What are the 2 layers of the dermis?

Answer 16

papillary layer and reticular layer

Question 17

What is the papillary layer?

Answer 17

Contains fine collagenous and elastic fibres that form a unique pattern to give finger prints.

Question 18

What is the reticular layer?

Answer 18

Contains dense interlacing white collagenous fibres to make the skin tough yet stretchable.

Question 19

What happens in wound healing?

Answer 19

Dermal fibroblasts form a dense mass of connective tissue fibers if not replaced by normal tissue this mass remains a scar.

Question 20

What are the 2 sensory receptors in the dermis?

Answer 20

Tactile corpuscle and the lamellar corpuscle.

Question 21

Where is the tactile corpuscle and what does it sense?

Answer 21

Beneath the dermis, sense touch and slight pressure.

Question 22

Where is the lamellar corpuscle and what does it sense?

Answer 22

Above the hypodermis sense vibration and deep pressure.

Question 23

What are the 2 different sweat glands found in the dermis?

Answer 23

Eccrine glands and apocrine glands.

Question 24

What is the location and function of the eccrine sweat glands?

Answer 24

They cover the total body surface and are very small coiled tubular glands they function throughout life by secreting perspiration or sweat to help eliminate waste and maintain a constant core body temperature.

Question 25

What is the location and function of the apocrine gland?

Answer 25

Limited distribution only in the armpit, ear canal. They are large simple branched tubular glands and begin to function at puberty. They secrete water ,uric acid and urea mixed with lipid mix.

Question 26

What are sebaceous glands and where are they found?

Answer 26

They are associated with the hair follicle near the surface in the dermis except for palms and the soles of the feet. they are acinar branched glands.

Question 27

What do sebaceous glands secrete?

Answer 27

Triglycerides, squalene and wax esters. The secretion increases in adolescence leading to the formation of pimples and blackheads.

Question 28

What is the treatment for acne?

Answer 28

Benzoyl peroxide- works as an antiseptic to reduce the number of bacteria on the surface of the skin.
Topical retinoids- Removing dead skin cells from the surface of the skin (exfoliating) which helps to prevent them building up within hair follicles.

Question 29

What are the 3 parts of the hair follicle?

Answer 29

Papilla- cluster of capillaries under germinal matrix.
Root- part of the hair embedded in follicle in the dermis.
Shaft- the visible part of the hair spilt into the medulla (inner core of hair) and the cortex (outer portion).

Question 30

How does this skin thermoregulate?

Answer 30

Evaporation is the main source of heat loss from the body, when your body temperature rises/decreases the hypothalamus controls the function of sweat glands and blood vessels of the skin.