A&P Skin Week 2 Achieve

The outermost superficial region of the skin?

The middle region of the skin?

The (superficial fascia) – deepest region of the skin?

The _ is composed of keratinized stratified squamous epithelium, consisting of four distinct cell types and four or five layers?

Cell types of this type of skin include keratinocytes, melanocytes, Merkel cells, and Langerhans’ cells?

This type of skin is the outer portion of the skin and is exposed to the external environment and functions in protection?

This skin cell produce the fibrous protein keratin?

This skin cell produce the brown pigment melanin?

These skin cells are epidermal macrophages that help activate the immune system?

These skin cells function as touch receptors in association with sensory nerve endings?

Layers of the Epidermis.
Deepest epidermal layer of the skin firmly attached to the dermis.
Consists of a single row of the youngest keratinocytes.
Cells undergo rapid division, hence its alternate name, stratum germinativum.

Layers of the Epidermis.
Cells contain a weblike system of intermediate filaments attached to desmosomes.
Melanin granules and Langerhans’ cells are abundant in this layer.

Layers of the Epidermis.
Thin; three to five cell layers in which drastic changes in keratinocyte appearance occurs.
Keratohyaline and lamellated granules accumulate in the cells of this layer.

Layers of the Epidermis.
Thin, transparent band superficial to the stratum granulosum.
Consists of a few rows of flat, dead keratinocytes.
Present only in thick skin.

Layers of the Epidermis.
Outermost layer of keratinized cells.
Accounts for 3/4 of epidermal thickness.
Functions include:.
Waterproofing, Protection from abrasion and penetration, Rendering the body relatively insensitive to biological, chemical, and physical assaults.

Skin Layers.
Second major skin region containing strong, flexible connective tissue.
Cell types include fibroblasts, macrophages, and occasionally mast cells and white blood cells.
Composed of two layers – papillary and reticular.
Contains the Appendages of the skin.

Layers of the Dermis.
Areolar connective tissue with collagen and elastic fibers.
Its superior surface contains peglike projections called dermal papillae.
Dermal papillae contain capillary loops, Meissner’s corpuscles, and free nerve endings.

Layers of the Dermis.
Accounts for approximately 80% of the thickness of the skin.
Collagen fibers in this layer add strength and resiliency to the skin.
Elastin fibers provide stretch-recoil properties.

Layers of the skin.
Subcutaneous layer deep to the skin.
Composed of adipose and areolar connective tissue.

3 Skin Pigments types.
Yellow to reddish-brown to black pigment, responsible for dark skin colors?
Freckles and pigmented moles – result from local accumulations of this?

3 Skin Pigments types.
Yellow to orange pigment, most obvious in the palms and soles of the feet?

3 Skin Pigments types.
Reddish pigment responsible for the pinkish hue of the skin?

Different types of sweat glands prevent overheating of the body; secrete cerumen and milk.
Found in palms, soles of the feet, and forehead.

Different types of sweat glands prevent overheating of the body; secrete cerumen and milk.
Found in axillary and anogenital areas.

Different types of sweat glands prevent overheating of the body; secrete cerumen and milk.
Modified apocrine glands in external ear canal that secrete cerumen.

Different types of sweat glands prevent overheating of the body; secrete cerumen and milk.
Specialized sweat glands that secrete milk.

Glands.

Simple alveolar glands found all over the body.
Soften skin when stimulated by hormones.
Secrete an oily secretion called sebum.

Filamentous strands of dead keratinized cells.
Contains hard keratin which is tougher and more durable than soft keratin of the skin.
Made up of the shaft projecting from the skin, and the root embedded in the skin.
Consists of a core called the medulla, a cortex, and an outermost cuticle.
Pigmented by melanocytes at the base of the hair.

Hair.
Root sheath extending from the epidermal surface into the dermis .
Deep end is expanded forming a hair bulb.
A knot of sensory nerve endings (a root hair plexus) wraps around each hair bulb.
Bending a hair stimulates these endings, hence our hairs act as sensitive touch receptors.

Types of Hair.

Pale, fine body hair found in children and the adult female.

Types of Hair.

Terminal – coarse, long hair of eyebrows, scalp, axillary, and pubic regions.

Functions of the Integumentary System.

Protection – chemical, physical, and mechanical barrier.
Body temperature regulation is accomplished by:
Dilation (cooling) and constriction (warming) of dermal vessels.
Increasing sweat gland secretions to cool the body.
Metabolic functions – synthesis of vitamin D in dermal blood vessels.
Blood reservoir – skin blood vessels store up to 5% of the body’s blood volume.
Excretion – limited amounts of nitrogenous wastes are eliminated from the body in sweat.
Cutaneous sensation – exoreceptors sense touch and pain

Skin Cancer.
Most skin tumors are benign and do not metastasize.
A crucial risk factor for nonmelanoma skin cancers is the disabling of the p53 gene.
Newly developed skin lotions can fix damaged DNA.

The three major types of skin cancer are?

Least malignant and most common skin cancer?
Stratum basale cells proliferate and invade the dermis and hypodermis?
Slow growing and do not often metastasize.
Can be cured by surgical excision in 99% of the cases?

Skin cancer that arises from keratinocytes of stratum spinosum?
Arise most often on scalp, ears, and lower lip?
Grows rapidly and metastasizes if not removed?
Prognosis is good if treated by radiation therapy or removed surgically?

Skin cancer of melanocytes is the most dangerous type of skin cancer because it is.
Highly metastatic.
Resistant to chemotherapy.

Burns.
only the epidermis is damaged.
Symptoms include localized redness, swelling, and pain.

Burns.
epidermis and upper regions of dermis are damaged.
Symptoms mimic first degree burns, but blisters also appear.

Burns.
entire thickness of the skin is damaged.
Burned area appears gray-white, cherry red, or black; there is no initial edema or pain (since nerve endings are destroyed.

Rule that Estimates the severity of burns.
Burns considered critical if:
Over 25% of the body has second-degree burns.
Over 10% of the body has third-degree burns.
There are third-degree burns on face, hands, or feet.

Developmental Aspects of the Integement.
Epidermis develops from ectoderm.
Dermis and hypodermis develop from mesoderm.
Lanugo is the downy coat of delicate hairs covering the fetus.
Vernix caseosa is the substance produced by sebaceous glands that protects the skin of the fetus in the amnion.

Developmental Aspects of the Integement.
Skin and hair become oilier and acne may appear.
Skin shows the effects of cumulative environmental assaults around age 30.
Scaling and dermatitis become more common.

Developmental Aspects of the Integement.
Epidermal replacement of cells slows and skin becomes thinner.
Skin becomes dry and itchy.
Subcutaneous fat layer diminishes, leading to intolerance of cold.
Decreased elasticity and loss of subcutaneous tissue leads to wrinkles.
Decreased numbers of melanocytes and Langerhans’ cells increase the risk of skin cancer.