Lecture 4: The Integumentary System

Name and describe three types of skin cancer.

Basal cell carcinoma: most common type, least dangerous, originates in stratum basal Squamos cell carcinoma: arises from Keratinocytes Malignant Melanoma: most deadly type, arises from melanocytes (suavely a preexisting mole) -early detection is crucial

Briefly describe the three basic layers of skin.

Epidermis: epithelial tissue Dermis: connective tissue Hypodermis: NOT a part of the integument (connective tissue)

1. Describe the size, thickness and functions of the integument. What structures, other than the skin, are included in the integumentary system?

Consists of appendages-skin, nails, hair, sweat glands, and sebaceous glands Thickness: ranges from 1.5-4 mm Functions: protection, prevent loss of water, temperature regulation, metabolic regulation, immune defense, sensory receptors, excretion by means of secretion

Compare and contrast the following glands in terms of basic structure, location in skin layers, location on the body, what is secreted, and function of the secretion -Merocrine sweat glands -Apocrine sweat glands -Sebaceous (oil) glands

Sebaceous (oil) glands -produces sebum -Holocrine Glands -occur over entire body except palms and soles Merocrine Sweat glands: most numerous, produces watery sweat. Apocrine Glands Axillary, nipple, anal and genital areas produces viscous sweat

Describe the structure and functions of the hypodermic (subcutaneous tissue).

Structure: areolar and adipose connective tissue -Not considered part of the integument Functions: anchors skin to underlying structures -thermal insulation -energy reservoir

Describe the basic structure of nails.

Structures: nail matrix, lanula (luna=moon) white part of nail, cuticle, free edge

Describe the basic structure, functions, types and growth cycles of hair

Three types: lanugo (fetal) vellus (fine hair on most of the body) terminal (head, pubic region, armpit, male facial hair) functions: protection, sense touch, reduce heat loss

Describe the structure of the dermis, including the cells and the extracellular matrix

Two layers: papillary layer (areolar CT) & reticular layer (Dense irregular CT) Vascular Innervated

The papillary layer of the dermis is rich in blood vessels and sensory nerve endings. Therefore, what are its main functions? Describe dermal papillae and epidermal ridges

dermal papillae: projections o fthe dermis toward the epidermis. Interlock with deep projections of epidermis called epidermal ridges. Together they increase the area of contact between the epidermis and dermis and connect these layers. -dermal papilla contain capillaries that supply nutrients to cells of epidermis -houses sensory receptors that continuously monitor touch not eh surface of the epidermis

Differentiate between first, second, and third degree burns.

first degree: damages epidermis second-degree: damages epidermis and part of the dermis third-degree: damages entire epidermis and dermis

Explain how hemoglobin, melanin and carotene contribute to skin color

hemoglobin: red pigmented protein that transports oxygen and carbon dioxide; responsible for characteristic bright red color of arterial blood melanin: any of the dark brown to black pigments that occur in the skin, hair, and retina carotene: class of yellow-red pigments widely distributed in plants and animals

Discuss the location and function of the following cell types found in the epidermis: keratinocyte, melanocyte, epidermal dendritic cell, tactile (Merkel) cell

keratinocyte: most abundant cell type in the epidermis and found throughout the epidermis; cells that produce keratin melanocyte: pigment-producing cell in the basal layer of the epidermis epidermal dendritic cell:

Explain the causes of acne (including whiteheads & blackheads)

plugged sebaceous ducts; blackheads part of skin is stretched back so can see dead skin cells-the bacteria and oil stuck in the pore

The reticular layer of the dermis is thick and rich in collagen fibers. Therefore, what functions does this layer perform? What structures are typically found in the reticular layer?

reticular: "network". These fibers conceal any distinct boundary between the papillary and reticular layers. Collagen fibers extend internally from the reticular layer of the dermis into the underlying subcutaneous layer. Structures found within reticular layer: dense irregular connective tissue, collagen fibers

Name and briefly describe the 5 layers of the epidermis. Which are found in thick skin? Which are found in thin skin?

stratum corneum stratum lucidem (thick skin only) stratum granulosum stratum spinosum stratum basale