Intergumentary System Flashcards
What type of epithelium is the epidermis?
Stratified squamous epithelium.
What are the functions of the skin?
Protect underlying structures from injury & invasion by microbes.
Protect against infection-mechanical barrier & sebum (oil) inhibits growth of certain bacteria.
Protects against harmful effects of the sun.
Hair protects head from injury & the sun.
Contains sensory nerve endings for pain, temperature & touch.
Regulates body temperature.
Excretion of waste products-salts, certain foods (garlic).
Vitamin D synthesis.
Prevents excessive water loss or entry.
How many laters does the epidermis have?
5 main layers
What is the name of the base layer?
Stratum basale
What does the epidermis consist of?
Dead cells filled with keratin & a fatty matrix
What are the properties of the epidermis?
Waterproof, abrasion-resistant barrier.
Has no blood supply.
What type of epithelia is the stratum basale?
Single layer of cuboidal or columnar cells
What does the stratum basale separate?
Epidermis & dermis
What type of cells is the stratum basale?
Germinal cells
What does the stratum basale do?
Divides rapidly to provide a continuous source of new skin cells.
What are new skin cells called?
Keratinocytes
What do keratinocytes do?
Migrate up towards the surface changing characteristics until they are shed.
What other than keratinocytes is found in the epidermis?
Melanocytes
What do melanocytes contain?
Melanin
If uv light is actioned on a substance called 7-dehydrocholestrol. What is produced?
Vitamin d
What is the purpose of the dermis?
Strong, stretchy layer that helps hold the body together.
What type of tissue is the dermis & what does it contain?
Dense connective tissue containing collagen & elastic fibres.
What is the difference of the dermis between males & females?
Thinner in females.
What is located in the dermis?
Structures that enable the skin to carry out many functions.
Dermis contains a fibrous protein arranged in bundles that lies mostly parallel with the skins surface. What is this called?
Collagen
What gives the dermis flexibility?
Elastic fibres
What do ruptures elastic fibres cause?
Stretch marks
What is the clinical term for stretch marks?
Striae
What in the dermis decreases with age?
Number of elastic fibres
Sunlight may damage fibres in the dermis regardless of the presence of what?
Melanin
What are intertwined in the dermis?
Blood vessels, lymph vessels & nerve endings.
What causes the natural folds & creases of the skin?
Langar lines (cleavage lines)
What does the dermis do to help prevent separation of dermis & epidermis?
Forms ridges & hollows
What is the hypodermis?
Adipose tissue (adipocytes) & loose connective tissue
What is the hypodermis responsible for?
Fat distribution ( gives body shape), attaches skin to underlying tissue, provides mechanical support, acts as an energy store
What are hairs?
Down growth of epidermal cells into the dermis.
Formed by multiplication of cells at bulb.
Hair grow from follicles at their base. What is this cluster of cells called?
Bulb
What is the process in which hairs are made?
Cells are pushed upward away from source of nutrition, they die & are then keratinised.
What is the name of the muscle that causes piloerection?
Arrector pili
How many types of sweat gland are there in the skin?
3
What is the most numerous type of swear gland?
Eccrine glands
Where are ecceine glands most abundant?
Palms of hands, soles of feet & forehead.
What do eccrine glands secrete?
Sweat (salt solution)
What is the purpose of sweat?
Allows the skin to cool as it evaporates.
How much sweat is it possible to loose for short periods during exercise or hot weather?
6ltr/hr
How much do we sweat in cold conditions?
500ml per day (insensible water loss)
What gland is larger than eccrine & most numerous in the axillae, genital area & around nipples?
Apocrine gland
What does apocrine sweat contain that makes it thicker & stickier?
Protein, fats & other substances
What breaks down sweat on the surface of the skin?
Bacteria
What can the bacteria breakdown of sweat cause?
Unpleasant odour / body odour
When do apocrine glands begin to function
Puberty
What glands are found everywhere except hands & feet, neck, scalp & back?
Sebacious (oil) glands
What do sebacious glands secrete?
Sebum
What does sebum contain?
Fatty substance containing cholesterol & other lipids.
What do sebacious glands secrete onto?
Hair follicles or directly onto the skin.
Where would you find ceruminous glands?
Ear canal
What do ceruminous glands secrete?
Ear wax
The skin contains receptors that can detect what?
Pressure, stretch, vibration, tickle, itch, pain, temperature, pressure
What nerves are found in the skin?
Pacinian corpuscle, ruffinis corpuscle, free nerve endings, meissners corpuscle, merkel discs
What is the purpose of the cutaneous circulation?
Skin can contribute to control of body temperature.
Arterioles carry oxygenated blood into dermis.
Capillaries (capillary loop) drain into network of small veins within dermis.
Larger veins carry deoxygenated blood away
The ears, nose, fingertips & lips have additional blood vessels known as?
Arterio-venous (av) anastomoses
The epidermis has no direct blood supply. So how does it receive its oxygen & nutrients?
Diffusion
What is vasoconstriction?
Narrowing of the blood vessels
What is vasodilation?
Widening of the blood vessels
