Integumentary System Flashcards
List the functions of the skin and relate them to its structure
- Resistance to trauma and infection - dendritic cells
- Barrier - Stratum Corneum
- Vitamin D synthesis
- Sensation - tactile cells/free nerve endings
- Thermoregulation - sweat glands, blood vessels, and subcutaneous fat
- Nonverbal communication
Describe the histological structure of the dermis (Hint: 2 layers)
Below epidermis
Papillary layer: superficial zone of the dermis.
lots of small blood vessels with a thin zone of areolar tissue near dermal papilla
Reticular layer: deeper and thicker zone of the dermis. Made up of dense, irregular connective tissue. Striae, stretch marks occur here which are tears in collagen fibers.
Describe the histological structure of subcutaneous tissue/hypodermis.
Subcutaneous tissue is in the hypodermis with more areolar and adipose tissue than dermis.
It pads the body and binds skin to underlying tissue; common site of injection. Subcutaneous fat is an energy reservoir and provides thermal insulation.
List the layers of the epidermis.
Can Lucy Grab Some Basil
Stratum Corneum Stratum Lucidum Stratum Granulosum Stratum Spinosum Stratum Basale
Describe the normal and pathological colors that the skin can have and explain their causes.
Melanin=skin color
eumelanin is brownish/black; pheomelanin is reddish/yellow
different skin colors=same number of melanocytes
Darker skin= melanin granules spread out
Lighter skin=melanin stays near stratum basale
Other pigments: hemoglobin, carotene (yellow egg)
Describe the common markings of the skin.
Friction ridges: markings on fingertips with oily fingerprints
flexion lines: creases on flexor surfaces on fingers, palms, and wrists (the lines used to palm read)
Describe the three types of hair.
Lanugo: fine hair with no pigment on fetus after 3 months of development
Vellus: fine, pale hair that replaces lanugo postbirth (2/3 hair on women, 1/10 hair on men, all body hair on children)
Terminal: long, coarse hair that is pigmented on head hair and pubic hair.
Describe the histology of a hair and its follicle.
Hair has three zones:
Bulb: swelling at base where hair originates in dermis/hypodermis
Root: remainder of hair in follicle
Shaft: the portion above the skin surface
Hair accessories:
dermal papilla: in bulb, bud of vascular connective tissue for hair nutrition
follicle: diagonal tube extending into surface.
hair receptors (arrector pili muscle): sensory nerve fibers entwining follicles that cause goosebumps
Describe the structure and function of nails.
Nails are derived from stratum corneum (thin dead cells with hard keratin)
Function: improve grooming, picking food, enhances touch sensitivity
Apocrine sweat (sudoriferous) gland
Location: groin, anal region, axilla, areola, beard in men. Inactive until puberty, ducts near hair follicle (biggest skin gland)
Function: produce milky sweat and fatty acids, responds to stress/sexual stimulation
Merocrine/Eccrine sweat (sudoriferous) gland
Location: dense on palm, soles, forehead, a simple tubular gland. Most numerous 3-4 million
Function: watery, perspiration that cools body down
Sebaceous gland
Location: flask shaped with ducts opening into hair follicles, holocrine secretion style
Function: secretes sebum, keeps skin and hair from being dry and cracked
Ceruminous gland
Location: coiled, simple tubular glands in external ear canal, modified apocrine gland
Function: Secretion combines with sebum and dead epithelium to form ear wax (cerumen)
Protects eardrum, waterproofs canal and kills bacteria/foreign particles.
Discuss the difference between breasts and mammary glands and explain there respective functions.
Mammary glands are a modifed apocrine sweat gland that develop during pregnancy and lactation. Rich secretion released through nipple for child.
Everyone has breasts.
Stratum Corneum
The surface layer. Consist of 30 layers of dead, scaly, keratinized cells. It helps resist abrasion, penetration and water loss.
