Patho - Term Test II (Integumentary System, MSK) Flashcards
Skin accounts for about ___% of body weight.
20
Primary function of skin is:
Protection (against microorganisms, UV radiation, mechanical stress, and loss of body fluids)
What additional functions does the skin have. Select all that apply.
1) immune surveillance
2) body temp. regulation
3) production of vitamin D
4) Touch and pressure receptors
All
The layer that contains macrophages, fibroblasts, fat cells, nerves, fine muscles, blood vessels, lymphatics, and hair follicle roots is known as what?
Hypodermis (subcutaneous layer)
Fingernails and toenails are made of what?
protective keratinized plates
Describe the fingernail/toenail composition/structure (6).
1) proximal nail fold
2) eponychium (cuticle)
3) matrix where the nail grows and its nail root
4) hyponychium (nail bed)
5) nail plate
6) paronychium (lateral nail fold)
What is the approximal rate of nail growth?
~1mm or less daily
Hair follicles start from where in the skin?
Starts from the matrix/bulb
Hair colour depends on what?
melanin-secreting melanocytes in the hair follicle
What do sebaceous glands secrete and what stimulates the growth of these glands?
Secretes sebum
Growth stimulated by androgens (so enlargement of these glands = early signs of puberty = oily teenagers)
Sebum is primarily composed of what substance, which allows for what function?
Lipids; allows for prevention of hair and skin drying
Sebaceous glands are numermous in which parts on the body?
Face, chest, back
Modified sebaceous glands are found where?
eyelids, lips, nipples, glans penis, prepuce (foreskin)
The type of gland that is found all over the body (but mostly in palms of hands, soles of feet, and forehead) and involved with thermoregulation is known as?
eccrine sweat glands
(Apocrine/eccrine) sweat glands produce more sweat.
Apocrine
Where are apocrine sweat glands found?
near bulbs of hair follicles in axillae, scalp, face, abdomen, and genital areas
How does perspiration have an odor?
Due to interaction of sweat (from apocrine sweat glands) and flora bacteria
Blood supply to skin is supplied by what?
papillary capillaries (plexus) of the dermis (and these are supplied by a deeper arterial plexus)
Regulation of body temperature in the skin is faciliated by what vascular structures?
Arteriovenous anastomoses (direct connections between small arteries and veins)
How is body temperature/heat loss regulated in the skin? 2 mechanisms.
1) variations in skin blood flow through opening and closing of arteriovenous anastomoses
2) evaporative heat loss of sweat
Which nervous symptom regulates vasoconstriction/vasodilation in the skin?
SNS - sympathetic nervous system (via alpha-adrenergic receptors in the skin)
Approximately ____ % of heat is lost through the skin.
80
Epidermis consists of what 4 types of cells?
1) keratinocytes
2) melanocytes
3) Dendritic/Langerhans cells
4) Merkel cells
Layers ot the epidermis (from superficial to deep).
Stratum corneum Stratum lucidum Stratum granulosum Stratum spinosum Stratum basale