05 integ std api

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Chapter 5 - The Integumentary System

Chapter Outline

IntroductionSkin

Epidermal Derivatives

Thermoregulation: Homeostasis of Body Temperature

Disorders: Homeostatic Imbalance

Notes

I. Introduction

A. An organ consists of a group of tissue that performs a specific function.

B. The tissues comprising the skin are the epithelium of the epidermis

and the connective tissues of the dermis.

C. A system is a group of organs working together toward common goals.

D. The integumentary system consists of the skin and its derivatives, such

as hair, nails, glands, and nerve endings.

II. Structure of the Skin

A. Objective:

1. Be able to complete this sentence: The medical specialty that deals

with diagnosing and treating skin disorders is

_______________________

B. Introduction

1. Objective:

of 11Human Anatomy and Physiology I (SC481)

Chapter 5 – The Integumentary System



D. Epidermis

1. Cells of the Epidermis

a) Objective: What is the purpose of the keratinocytes and

melanocytes?

b) Keratinocytes - (ker - a - TIN - o - sites) produce the protein

keratin that helps keep the skin waterproof and protect the

underlying tissues.

c) Melanocytes (MEL- a - no - sites) produce melanin, which

transfer granules of melanin to keratinocytes. Melanin absorbs

UV light. The melanin granules cluster to form a protective veil

over the nucleus on the skin side surface. This protects theDNA from the damaging UV light.

d) Langerhans cells - interact with white blood cells called helper T

cells in immune responses. Are located in the epidermis.

e) Merkel cell - found in the deepest layer (stratum basale) of the

epidermis of hairless skin, where they are attached to

keratinocytes. Merkel cells make contact with the flattened

portion of the ending of a sensory neuron, called a tactile

(Merkel) disc, and are thought to function in the sensation of

touch.





2. Layers of the Epidermis

a) Objective: Be able to list the layers of the epidermis and identify

their features.

b) ______________________________ – consists mostly of a

single layer of cells that multiply and move upward. Consists

mostly of keratinocytes.

c) ______________________________ – several layers of cells

thick. Keratinocytes are somewhat flattened and irregular in

shape.

d) ______________________________ – three to five layers thick.

The process of keratinization begins in this layer (to bedescribed below). The cells contain a substance (keratohyalin)

that is a precursor to the keratin.

e) _______________________________– this layer is present

only in thick skin (e.g., palms and soles of feet).

f) _______________________________– 25-30 layers thick of

flat, dead cells full of keratin. Cells are continually shed.

g) Layers of the skin can be remembered by using this mnemonic

device – Can Little Girls Speak German? (corneum, lucidum,

granulosum, spinosum, germinativum)

3. Keratinization and Growth of the Epidermis - Keratinization is the

process of a cell accumulating keratin, along with the

disappearance of the nucleus, cytoplasm and organelles, and death

of the cell.

E. Dermis

1. This is a layer of connective tissue consisting of collagen fibers and

elastic fibers and a few of the following cells: fibroblasts,

macrophages, and adipocytes.





2. Structures embedded in the dermis - Blood vessels, nerves, glands

and hair follicles.

3. Papillary region

a) This region contains fingerlike projections called dermal papilla.

b) Some dermal papillae contain tactile receptors called corpuscles

of touch.

4. Reticular region

a) Mostly interlacing bundles of collagen fibers and coarse elastic

fibers. There is adipose tissue, hair follicles nerves, oil glands

and the ducts of sweat glands between the fibers. The

combination of collagen and elastic fibers give the skin strength,

extensibility and elasticity. (Extensibility is the ability to stretch

and elasticity is the ability to return to the original length. Small

tears can occur in the dermis during pregnancy, obesity and

edema. Small tears in the dermis are initially red and remain

visible later as silvery white streaks called stretch marks or

striae.)

F. The Structural Basis of Skin Color

1. Objective:

a) Give the names of the three pigments that contribute to skin

color and indicate the color that each produces

2. Three pigments - melanin, carotene, and hemoglobin

a) Melanin

(1) Causes skin to range from pale yellow to red to tan toblack

(2) May cluster in patches giving freckles. Age (liver) spots

can also develop.





B. Skin Glands

1. Sebaceous (Oil) glands

a) Objective: What is the name of the substance secreted by the

sebaceous glands and what is the purpose of it?

b) The sebaceous glands secrete an oil called _______________

c) The purpose of the oil is _______________________________

___________________________________________________

2. Sudoriferous (sweat) glands

a) Objective: Be able to describe the principal function of sweat?





A. Burns

1. Protection by the skin is disrupted with a burn. The three ways that

burns do this are:

a) permit microbial invasion and infection

b) loss of fluid

c) loss of thermoregulation

2. First-degree burn

a) Amount of skin burned - only the surface epidermis

b) Appearance - redness but no blisters.

c) Healing period - Generally, two or three days

3. Second-degree burn

a) Amount of skin burned - entire epidermis and possibly parts of

the dermis

b) Appearance - redness, blisters, edema.

c) Healing period - three to four weeks if no infection

4. Third-degree burn





a) Amount of skin burned - epidermis, dermis and epidermal

derivatives are destroyed.

b) Appearance - vary in appearance; marble-white, mahogany

colored to charred, dry wounds. Marked edema. Burned regionis numb because sensory nerve endings have been destroyed.

c) Healing period - Skin regeneration is low.

B. Skin Cancer

1. The most prevalent life-threatening skin cancer in women in young

women are malignant melanomas.

C. Acne - Inflammation of the sebaceous glands.

D. Pressure sores

1. Also known as decubitus ulcers or bedsores.

2. Caused by a constant deficiency of blood supply to tissues that are

subjected to extended pressure against an object. Results in tissue

ulceration. Small breaks in the epidermis become infected and the

subcutaneous and deeper tissues are damaged.

E. Warts - caused by a virus (papillomavirus). Most warts are

noncancerous.





F. Athlete's foot

G. Chickenpox

H. Shingles

I. Cold sore

J. Contusion (bruise)

K. Blisters

L. Measles, German (Rubella)

M. Measles, red (Rubeola)

N. Impetigo

O. Ringworm

P. Spotted fever, Rocky Mountain

Q. Ectoparasite, Phthirius pubis (crab) - Ectoparasites often inhabit the

surface of our bodies, harvesting nutrients from skin, secretions,

andsometimes blood. They spread from one person to another by

physical contact.



05 integ std api

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