Ch. 5 Objectives A&P I

epidermis

superficial, outer layer of skin. it is made primarily of keratinized stratified squamous epithelium

dermis

the deeper connective tissue layer that contains blood vessels, nerves, hair follicles, and glands

hypodermis

located beneath the dermis. it is primarily made of adipose and connective tissue and attaches the skin to underlying structures

label the image 1-18

1. hair shaft

2. epidermis

3. papillary layer

4. dermis

5. reticular layer

6. hypodermis

7. sensory nerve fiber with free nerve endings

8. lamellar corpuscle

9. hair follicle receptor

10. adipose tissue

11. dermal vascular plexus

12. hair root

13. hair follicle

14. sebaceous oil gland

15. arrector pili muscle

16. arrector sweat gland

17. sweat pore

18. dermal papillae

stratum basale

deepest epidermal layer. one row of actively mitotic stem cells; some newly formed cells become part of the superficial layer. see occasional melanocytes and tactile epithelial cells. merkel cells involved in light touch sensation

stratum spinosum

several layers of keratinocytes unified by desmosomes. cells contain thick bundles of intermediate filaments made of pre-keratin. Langerhan’s (dedritic) cells that help to activate the immune system

stratum granulosum

one to five layers of flattened cells, organelles deteriorating. cytoplasm full of lamellar granules (release lipids) and keratinhyaline granules

stratum corneum

most superficial layer; 20-30 layers of dead cells; essentially flat membranous sacs filled with keratin. glycolipids in extrecellular space.

ACRONYM for 4 layers of Epidermis

Be Students of Grace, (Love), and Compassion

stratum lucidum

present only in thick skin. thin translucent band of dead keratinocytes. deep to the stratum corneum, superficial to the stratum granulosum

papillary layer

areolar connective tissue. projections into epidermis called papillae, contain capillaries, free nerve endings, touch receptors (Meissner’s corpuscles)

reticular layer

80% of thickness of dermis, Pacinian corpuscles (sense deep pressure), dense irregular connective tissue, bundles of collagen fibers, less dense regions of bundles form lines of cleavage skin

formation of a fingerprint

formed by dermal papillae and the pattern of epidermal ridge if the fingerprint

melanin

yellow to red-brown to black, protects DNA in skin cells from UV light. melanocytes stimulates during sun exposure

carotene

(yellow to orange) pigment found is some plants (eg carrots). most obvious in palms and soles.

hemoglobin

pinkish hue of fair skin reflects crimson of oxygenated blood

clinical indicators

cyanosis, erythema, pallor, jaundice, bronzing, bruising

cyanosis

dark blue, hemoglobin poorly oxygenated, heart failure/severe respiratory disorders

erythema

embarrassment, fever, hypertension, polycythemia, inflammation, allergy

pallor

anemia, low blood pressure, emotional stress, fear, anger

jaundice

liver disorder, accumulation of yellow bile pigments

bronzing

Addison’s disease, hypofunction of adrenal cortex

black and blue marks, bruises

blood has escaped circulation and clotted beneath skin (hematoma)

sweat gland types

eccrine or merocrine glands

sweat glands

produce sweat (99% water, also sodium chloride, wastes, and lactic acid), sweat prevent body overheating, glands located over entire skin surface

sabaceous (oil) glands

produce sebum secreted into hair follicle to lubcricate hair and skin/ bacteriocidal, acne, glands located all over body except palms and soles

acne

active inflammation of sebaceous glands. whitehead= sebaceous gland duct blocked by sebum. seborrhea= “cradle cap”

hair papilla

located at the base of the hair follicle, contains blood vessels that provide nutrients to the growing hair

hair matrix

area of actively dividing cells surrounding the papilla. produces new hair cells

arrector pili

small smooth muscle attached to the hair follicle. contracts and causes the hair to stand up, producing goosebumps

hair shaft

the portion of hair extending above the skin surface. made of dead, keratinized cells

hair root

portion of the hair located below the skin surface inside the follicle

hair bulb

enlarged base of the hair root. contains the matrix and surrounds the hair papilla

hair color

comes from melanin produced by melanocytes in the hair matrix

major factors affecting hair growth

genetics, hormones, age, nutrition, overall health, stress, certain diseases or medications

alopecia

partial or complete hair loss, which can occur in the scalp or other parts of the body

fingernail

hard structure made primarily of dead keratinized cells

structures of fingernail

nail plate, nail bed, nail root, nail matrix, lunule, nail folds

nail plate

hard visible portion of the nail

nail bed

skin underneath the nail plate

nail root

portion of the nail embedded beneath the skin

lunule

whitish, crescent-shaped area at the base of the nail. visible portion of the nail matrix

nail folds

skin folds surrounding and overlapping the edges of the nail

function of the integumentary system

protection, body temperature regulation, cutaneous sensation, metabolism, blood reservoir, excretion

cell carcinoma, basal carcinoma, and melanoma

melanoma: cancer of melanocytes. less common but more dangerous because it can rapidly spread to other organs.

basal carcinoma: most common type. develops from cells in the stratum basal. grows slowly and rarely metastasizes.

cell carcinoma: cancer of keratinocytes in the epidermis. can be more aggressive than basal cell carcinoma and may metastasize

ABCDE rule for melanoma

A- asymmetry: one half of the mole doesn’t match the other half

B- border: edges are irregular, uneven, or poorly defined

C- color: color is uneven or contains multiple colors

D- diameter: a suspicious lesion is often larger than 6 mm

E- evolving: the mole changes in size, shape, color, or appearance

three types of burns

first degree burn: involved only the epidermis, skin is red and painful, ex: mild sunburn

second-degree burn: involves the epidermis and part of the dermis, usually produces redness, pain, swelling, and blisters

third-degree burn: destroys the epidermis and dermis and may damage deeper tissues, skin may appear white, brown, black or charred. may not be painful in the center because nerve endings have been destroyed

critical burn: covers a large percentage of body, involves the face, hands, feet, or major joints, involves the respiratory system/airway, is full-thickness (third degree) burn over a significant area

rule of nines

head and neck = 9%

upper limb (each) = 9%

anterior trunk = 18%

posterior trunk = 18%

each lower limb = 18%

perineum = 1%

athlete’s foot (tinea pedis)

fungal infection of the skin, causes itching, redness, scaling, and sometimes cracking, thrives in warm, moist environments

boil (furuncle)

infection of a hair follicle and surrounding tissue usually caused by bacteria

carbuncle

cluster of connected boil usually involves a deeper and larger infection

cold sores

caused by herpes simplex virus, usually HSV-1. produce painful fluid-filled blister around the lips or mouth. the virus remains in the body and can reactivate

contact dermatitis

inflammation caused by contact with an irritating substance or allergen. causes redness, itching, swelling, and sometimes blisters

impetigo

highly contagious bacterial skin infection. common in children. produces red sores that develop characteristic yellowish/honey colored crusts

psoriasis

chronic inflammatory skin disorder, skin cells reproduce too quickly, causing thick, raised patches covered with silvery scales, often affects the elbows, knees, scalp, and other areas. it not contagious.