Skin Flashcards
What is Dermatology?
The study and treatment of the integumentary system:
Skin, hair, nails, and cutaneous glands
What are the 3 layers of skin?
Epidermis: Epithelium of the skin
Dermis: Connective Tissue of the skin
Hypodermis: connective tissue just underneath the skin
Thick Skin
Plams of hands, front of fingers, soles of feet, bottom of toes
- Hairless
- DOES sweat
- adaptive for high friction
Thin Skin
- Covers most of the body
- Hairy, has both sebaceous oil glands and sweat glands
Epidermis
- Keratinized Stratified Squamous Epithelium
- Avascular
- Sparse Nerve Endings
Name the 2 layers of the Dermis
Papillary Layer
- superifical, thin layer
- Aerolar Tissue
- Rich in blood vessels
Reticular Layer
- Deep, thick layer
- Dense, Irregular connective tissue
- Stretch marks
Hypodermis
- Not a true layer of skin
- located below the dermis
- Contains adipose (fat) and aerolar tissue
Functions: - energy storage
- Thermal insultation
- connection to deeper tissue
Cells of the Epidermis
Cells of the Epidermis
Keratinocytes
Stem Cells
Melanocytes
Tactile Cells
Dendritic Cells
Cells of the Epidermis
Keratinocytes
Hard, waterproof protein cells
Cells of the Epidermis
Stem Cells in Epidermis
Produce keratinocytes
Found in stratum basale (deepest layer of epidermis)
Source of mitosis
Cells of the Epidermis
Melanocytes
Produce Melanin
- skin pigment
- Found in stratum basale (deepest layer of epidermis)
Cells of the Epidermis
Tactile (Merkel) Cells
Touch receptors that join with nerves
Found in stratum basale
Dendritic (Langerhans Cells)
Immune Surveilance
Found in stratum spinosum and stratum granulosum (two middle layers of epidermis)
Layers of the Epidermis
Most superficial to deepest: (CLGSB)
- Stratum Corneum
- Stratum Lucidum
- Stratum Granulosum
- Stratum Spinosum
- Stratum Basale
Stratification of the Skin and Hypodermis
Stratum Corneum
Dead, Keratinized cells of the skin surface (1st layer of Epidermis)
Stratification of the Skin and Hypodermis
Stratum Lucideum
Clear, featureless zone seen in only thick skin (2nd layer of Epidermis)
Stratification of the Skin and Hypodermis
Stratum Granulosum
2 to 5 layers of cells of dark-staining keratohyalin (3rd layer of Epidermis)
Stratification of the Skin and Hypodermis
Stratum Spinosum
Many layers of keratinocytes (4th layer of Epidermis)
Stratification of the Skin and Hypodermis
Stratum Basale
Single layer of cells on basement membrane, site of mitosis (5th layer of Epidermis, last layer)
Stratification of the Skin and Hypodermis
Dermis
Fibrous connective tissue, mixed with blood vessels and nerve endings
Has sweat glands and hair follicles
Melanin
Melanin is produced by melanocytes
Eumelanin: brownish black
Pheomelanin: reddish yellow
Hemogoblin
red pigment in blood
Diagnostic Skin Colors
Cyanosis
Blueness
Lack of oxygen
Diagnostic Skin Colors
Erythemia
Redness
Increased blood flow
Ex. stress or embarrassment
Diagnostic Skin Colors
Pallor
Pale or ashen
Reduced Blood flow
Albinism
White
Genetic lack of melanin
Jaundice
Yellow
Liver cannot breakdown bilirubin (breakdown by product of hemoglobin)
Hematoma
Bruise (slight purple)
Hair
Accessory organ of skin (ex. nails, skin glands)
Filament of keratinized cells
Grows from a tube called a hair follicle
Downy Hair
Hair grown on a fetus
- Fine, unpigmented hair
Vellus Hair
- Fine, unpigmented
- 2/3 of hair on women
- 1/10 of hair on men
All hair of children except eyelashes, eyebrows, and scalp
Terminal Hair
-Course, pigmented hair
-Eyebrows, eyelashes, and scalp
After puberty:
Axillary hair
Pubic
Male facial hair
Some hair on trunk and limbs
Functions of Hair
What is the purpose of hair on limbs and torso?
Serves a sensory purpose in detection
(ex. small insects crawling on skin)
Functions of Hair
Scalp Hair
Heat retention, protection from sun
Functions of Hair
Beard, Axillary, and Pubic Hair
Shows sexual maturity from puberty
Functions of Hair
Guard hairs
Help keep foriegn objects out of nostrils and auditory canal, eyelashes keep debris away from eyes
Functions of Hair
Eyebrows
Enhance facial expression
Three zones along length of hair
(BRS)
Blub
- where hair orginates from dermis
- Hair matrix (hair growth center from mitosis)
Root
- remainder of hair within follicle
- dead tissue
Shaft
- Portion above the skin
- Dead tissue
3 Layers to a hair
Medulla
- Internal layer
Cortex
- Bulk of hair
Cuticle
- Outer layer
Anatomy of a fingernail
Nail plate
- Free edge
- Nail body
- Nail root
Nail fold
-Nail groove
Nail bed
-Nail matrix (Source of nail growth)
- Eponychium
Name the 3 Cutaneous Glands
Eccrine Gland
Apocrine Gland
Sebaceous Gland
Sweat Glands
Apocrine Glands
- Produce sweat with many fatty acids
- Develop in puberty
- responds to stimuli
- Ducts open into hair follicle
Sweat Glands
Eccrine Glands
- Numerous, widespread, glands
- Found on palms, soles, and forehead
- Simple ducts that are pores on skin surface
Sweat Glands
Sebaceous Glands
- Holocrine secretion
- Keep skin and hair from becoming brittle due to OIL secretion
Ceruminous Glands
- Found in auditory Canal
- waterproofs canal, kills bacteria, and coats guard hairs
Mammary Glands
- produce milk
- modifed Apocrine gland
What causes Skin Cancer?
By UV rays
From natural sunlight and tanning beds
Skin Cancer
Basal Cell Carcinoma
Most common
Least dangerous, hardly spreads
Arises from Stratum Basale and invades Dermis
Skin Cancer
Squamous Cell Carcinoma
Arises from keratinocytes of stratum spinosum
Can spread to lymph nodes
Can be lethal
Melanoma
Most deadly, but in 5% of cases
Arises from melanocyte of existing mole
Spreads quickly, often fatal if not treated right away
