PH1124 - Skin & the integument system Flashcards
What are the 3 layers of the skin?
epidermis, dermis, hypodermis (subcutaneous layer)
What are the 3 main cells in the epidermis?
Keratinocyte, Melanocyte, langerhans
What is the function of a Keratinocyte?
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.
What is the function of an melanocyte?
Contribute to skin colour, filter UV light.
What is the function of Langerhans?
Immune surveillance, they are dendritic antigen presenting cells.
What are the main cells in the dermis?
Fibroblast and Dendritic cells.
What is the function of a fibroblast?
Produces collagen to make fibres.
What is the function of dendritic cells?
Antigen producing cells so involved in immune surveillance.
What are the 2 different layers in the epidermis?
The proliferating layer and the differentiating layer.
What are the 2 layers that make up the proliferating layer?
The stratum basale and the lamina basale.
What are the 3 layers that make up the differentiating layer?
Stratum corneum, stratum granulosum and the stratum spinosum.
What processes start to happen in the stratum granulosum?
Lipid extrusion, cornification (Formation of cornified envelopes)
What is desquamation?
Shedding off of dead skin cells
How is psoriasis caused?
Autoimmune disease where there is an increased in oxidised lipids that causes hyperproliferation of keratinocytes.
How is eczema caused?
Alteration in the ceramide species that causes a perturbed barrier causing inflammation and infection.
What are the 2 layers of the dermis?
papillary layer and reticular layer
What is the papillary layer?
Contains fine collagenous and elastic fibres that form a unique pattern to give finger prints.
What is the reticular layer?
Contains dense interlacing white collagenous fibres to make the skin tough yet stretchable.
What happens in wound healing?
Dermal fibroblasts form a dense mass of connective tissue fibers if not replaced by normal tissue this mass remains a scar.
What are the 2 sensory receptors in the dermis?
Tactile corpuscle and the lamellar corpuscle.
Where is the tactile corpuscle and what does it sense?
Beneath the dermis, sense touch and slight pressure.
Where is the lamellar corpuscle and what does it sense?
Above the hypodermis sense vibration and deep pressure.
What are the 2 different sweat glands found in the dermis?
Eccrine glands and apocrine glands.
What is the location and function of the eccrine sweat glands?
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.
What is the location and function of the apocrine gland?
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.
What are sebaceous glands and where are they found?
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.
What do sebaceous glands secrete?
Triglycerides, squalene and wax esters. The secretion increases in adolescence leading to the formation of pimples and blackheads.
What is the treatment for acne?
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.
What are the 3 parts of the hair follicle?
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).
How does this skin thermoregulate?
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.
