A&P 1: Integumentary System Flashcards
4 main functions of the integumentary system
i. protecting the body
ii. temperature regulation
iii. production of vitamin D
iv. sensations
Skin
the largest body organ
3 layers of skin
epidermis (superficial), dermis (middle), and hypodermis (deepest)
3 cell types in the epidermis
i. keratinocytes
ii. basal cells
iii. melanocytes
Keratinocytes
most abundant type in the epidermis; squamous cells filled with keratin that provide toughness and tear resistance; tight junctions and desmosomes link them together and exocytosis allow them to release lipids, helping to waterproof the epidermis; take up melanin through endocytosis
Basal Cells
stem cells found at the bottom of the epidermis; they regenerate the epidermis by continuously dividing to make new keratinocytes
Melanocytes
located deep in the epidermis; produce melanin and release it by exocytosis; everyone has the same number of melanocytes, but some people produce more melanin than others
Melanin
- tan-colored protein and the human body’s natural sunblock chemical; absorbs UV rays and protects the body from UV damage
- people produce lighter or darker forms of melanin; there are six varieties of melanin
Callous
increased thickness in a region of the epidermis; caused by friction/rubbing; basal cells sense the friction, and this triggers more cell division, so there are more keratinocytes being made than those being shed
Dandruff
increased shedding of keratinocytes in the scalp; caused by a fungal keratinocyte infection that kills them off and makes them shed prematurely
Psoriasis
auto-immune disease where keratinocytes are mistaken for microbes by the immune system, leading to premature shedding; can be treated with immunosuppressive medications
Dermis
middle layer of the skin; made of connective tissue
2 regions of the dermis
i. papillary region
ii. reticular region
Papillary Region
contains:
* areolar connective tissue that binds the epidermis and dermis together
* blood vessels, nerves, sensory receptors, lymphatic vessels
* dermal papillae: ridges/bumps that project up into the epidermis; increase binding of the epidermis to the dermis; they’re larger in thicker areas of the skin (i.e., palms +soles) and this forms prints
Reticular Region
consists of dense irregular connective tissue, providing the skin with toughness; contains blood vessels, nerves, sensory receptors, oil glands, hair follicles, lymphatic vessels, and bodies of sweat
Hypodermis
bottom layer of the skin, also called the “subcutaneous layer”; composed of adipose tissue, stores triglycerides for fuel, insulates heat, and pads the body
3 factors/pigments that contribute to skin color
i. melanin
ii. carotene
iii. hemoglobin
Carotene
a type of vitamin A; orange-colored chemical that gives the skin its orangish hue; also found in yellow and orange vegetables
Hemoglobin
red-colored protein in blood that makes the skin a reddish color; blood in the capillaries of the dermis and hypodermis help make the skin appear red
Suntan
high melanin production in the skin; UV stimulates the melanocytes to produce more melanin
Freckles
small patches of skin where melanocytes produce a high amount of melanin
Mole
a high number of melanocytes and large amount of produced melanin in a region of the skin
Albinism
genetic condition where an individual’s melanocytes don’t produce any melanin
Vitiligo
auto-immune condition where the immune system attacks and kills melanocytes in patches/blotches of skin
Tinea
also called “sunspots”; caused by a fungal infection that kills melanocytes
Tattoo
ink being injected into the skin’s dermis
3 functions of hair
i. shades the skin
ii. warmth
iii. touch/movement sensations
Hair Follicle
holds the hair in the skin
Matrix
portion of the follicle with basal cells and melanocytes
Arrector Pili Muscle
makes the hair stand on end-smooth muscles
Hair Root Plexus
nerve that’s activated by hair movement
Process of hair growth
the basal cells in the matrix divide into new keratinocytes at the base of the hair; hair can grow for several years, fall out of the follicle, and the matrix allows new hair to sprout; testosterone can make the hair grow thicker/wider
Hair Colors
- dark hair - large amount of melanin
- light/blonde hair - low amount of melanin
- red hair - modified form of melanin
- grey hair - mix of white and colored hair
- white hair - no melanin
Hair Shapes
- straight hair - circular-shaped melanocytes
- wavy hair - oval-shaped melanocytes
- curly hair - modified/irregular-shaped melanocytes
Baldness
also called “male pattern baldness”; caused by a type of testosterone that the body makes later in life; causes the follicle to degenerate prematurely
Rogaine Type meds
increased blood flow to the skin and increased nutrient delivery to the follicle
Oil Glands
also called “sebaceous glands”; pouch-like glands connected to hair follicles; secrete oil, or “sebum”, onto the hair
Sebum
- made of ipids and contains anti-microbial factors
- serves as the body’s natural hair conditioner
- stops hair and skin from drying out and cracking/breaking
- also hepls waterproof the skin and stop growth of certain bacteria
Acne
infected oil gland; usually caused by bacteria
2 types of sweat glands
i. eccrine
ii.apocrine
Eccrine Sweat Glands
- highly concentrated in skin of the palms, soles, and forehead
- secrets a clear, watery sweat containing dissolved salts and wastes (urea, lactic acid, CO2, alcohol)
- excretes wastes and cools the body
- when body temperature increases during excitement, stress, or exercise, they’re stimulated to secrete sweat pools in skin
Apocrine Sweat Glands
- found in skin of the armpits, nipples, groin, and face
- secrete a milky-colored sweat containing everything in eccrine sweat with additional proteins and lipids
- The proteins and lipids are thought to function as pheremones: scent/fragrance molecules that attract a mate
Tumor
an abnormal growth of cells; 2 types
Benign Tumor
abnormal cell growth that isn’t dangerous to one’s health (not cancerous)
Malignant Tumor
abnormal cell growth that IS dangerous for one’s health (cancerous); can interfere with functioning organs
Metastasis
spread of cancer cells; when these cells break off of a tumor, they travel thoughout the body and form a new tumor elsewhere in the body
3 common skin cancers
i. basal cell carcinoma
ii. squamous cell carcinoma
iii. melanoma
Basal Cell Carcinoma
tumor made of mutant/irregular basal cells; tumors look like red moles; least malignant of the three types
Squamous Cell Carcinoma
tumor made of mutant keratinocytes; tumors look like warts and are commonly formed on the scalp, ears, lips, or face
Melanoma
tumors of mutant melanocytes; most malignant of the three types; tumors look like moles and cells metastisize readily; this is difficult to treat becasue these cancer cells can’t be killed by conventional cancer meds
ABCDE Method of Melanoma Detection
A - Asymmetry
B - Irregular Border
C - Multi-Colored
D - Diameter > Pencil
E - Evolution in Size/Shape
Risk Factors for Skin Cancer
- UV exposure throughout life
- multiple sunburns
- fair skin, blue eyes, blonde, or red hair
- if your skin doesn’t tan
- heredity/family history/genetics
Burns
damage to the skin caused by heat, chemicals, friction, UV/radiation, electricity, or the cold; 3 types
First Degree Burns
the least severe burn; there’s only damage to the epidermis; inflammation through redness, heat, pain, or swelling
Second Degree Burns
damage to the epidermis and dermis; inflammation and blistering (fluid between the dermis and epidermis)
Third Degree Burns
the most severe burn; damage to all three layers of the skin; microbes can enter through the burn site, making it life-threatening and difficult to treat; look like burnt BBQ or charred meat
