Anatomy

System that includes the skin and its derivatives

What the derivatives of skin?

Epithelial layer of skin

Layer of connective tissue, nerve & muscle

What is the Subcutaneious tissue (subQ or hypodermis)?

Composed of keratinized stratified squamous epithelium

Contains no blood vessels

4 types of cells in it

Has 4/5 distinct strata (layers) of cells

What are the four cell types of the epidermis?

Produces keratin

Produces melanin pigment

How is melanin transferred to other cells?

From bone marrow (modified monocytes)
Provide immunity (ingest bacteria and viruses)

In deepest layer
Form touch receptor with sensory neuron

Deepest single layer of cells
Called stratum germinativum

Combination of merkel cells, melanocytes, keratinocytes & stem cells that divide repeatedly
Cells attached to each other and to basement membrane

8-10 cell layers held together by desmosomes

Stratum Spinosum:
What happens to the cells during slide preparation?

Stratum Spinosum: How is melanin taken in?

3-5 layers of flat dying cells
Show nuclear generation
Contain dark-staining keratohylin granules

3-5 layers of clear, flat, dead cells
Contains precursor of keratin
Seen in thick skin on palms & soles of feet

25-30 layers of flat dead cells filled with keratin and surrounded by lipids
Continuously shed
Barrier to light, heat, water, chemicals & bacteria
Friction stimulates callus formation

What are the two types of skin?

Describe thin skin (3 points)

Describe thick skin (3 points)

Describe the process of Keratinization & Epidermal Growth

Connective tissue layer composed of collagen & elastic fibers, fibroblasts, macrophages & fat cells
Contains hair follicles, glands, nerves & blood vessels

What are the 2 major regions of dermis?

Top 20% of dermis
Composed of loose CT & elastic fibers
Finger like projections called dermal papillae

What are the 3 functions of the papillary region?

Dense irregular connective tissue
Contains interlacing collagen and elastic fibers
Packed with oil glands, sweat gland ducts, fat & hair follicles
Provides strength, extensibility & elasticity to skin– stretch marks are dermal tears from extreme stretching

Where do epidermal ridges form?

What do epidermal ridges give us? (2 things)

What are the 7 functions of skin?

What is Thermoregulation?

Adjusting flow of blood to body surface:
What happens during moderate exercise?

Adjusting flow of blood to the body surface:
What happens with extreme exercise?

What do humans do to raise internal body temperature as needed?

How does skin provide protection? (4 points)

Touch, temperature, pressure, vibration, tickling and pain sensations arise from the skin

Only a minor role is played by the skin
400 mL of water evaporates from it daily
Small amounts salt, CO2, ammonia and urea are excreted
Lipid soluble substances can be absorbed through the skin
– vitamins A, D, E and K, Oxygen and CO2
– acetone and dry-cleaning fluid, lead, mercury, arsenic, poisons in poison ivy and oak

Blood can be stored in venous vessels located in the dermis and hypodermis

Describe the synthesis of Vitamin D?

Why is vitamin D important?

How are hair, oil glands, sweat glands and nails formed?

What are the 4 functions of hair?

What are the 3 parts of the hair shaft?

What ar the 3 part so the hair structure?

What is the base of the follicle called and what does it have?

What is the difference between the external root sheath and the internal root sheath?

Smooth muscle in dermis contracts with cold or fear
Forms goosebumps as hair is pulled vertically

Detects hair movement

How does hair have color?

True or false: Dark hair contins true melanin
True False

What does blonde and red hair contain?

Why does hair go grey?

Why does hair go white?

Oil glands

Sweat glands

Wax glands

Milk glands

Secretory portion in the dermis
Located on most of body except palm of hands and sole of feet
Most open onto hair shafts

Combination of cholesterol, proteins, fats & salts
Keeps hair and skin soft & pliable
Inhibits growth of bacteria & fungi(ringworm)
Holocrine type of excretion

Bacterial inflammation of glands
Secretions stimulated by hormones at puberty

Most areas of skin
Secretory portion in dermis with duct to surface
Regulate body temperature with perspiration

Which glands:
Armpit and pubic region
Secretory portion in dermis with duct that opens onto hair follicle
Secretions more viscous

What are the two types of sweat glands?

What are nails composed of?

What is the nail body pink?

Which part of the nail is...
Buried under skin layers
Lunula is white due to thickened stratum basale

Which part of the nail is...
Stratum corneum layer

What are the 4 functions of nails?