integumentary system

13
1 1 Human Anatomy, First Edition McKinley & O'Loughlin Chapter 5 Lecture Outline: Integumentary System 2 5-3 The Integument The skin that covers your body. Skin is also known as the cutaneous membrane. Integumentary system consists of the skin and its derivatives—nails, hair, sweat glands, and sebaceous glands.

Upload: janice-nieves

Post on 12-Nov-2014

700 views

Category:

Health & Medicine


1 download

DESCRIPTION

 

TRANSCRIPT

Page 1: Integumentary system

1

1

Human Anatomy, First EditionMcKinley & O'Loughlin

Chapter 5 Lecture Outline:Integumentary System

2

5-3

The Integument

The skin that covers your body. Skin is also known as the cutaneous membrane. Integumentary system consists of the skin and its derivatives—nails, hair, sweat glands, and sebaceous glands.

Page 2: Integumentary system

2

5-4

The IntegumentIs the body’s largest organ. Its surface is covered by an epithelium that protectsunderlying body layers. The connective tissues contain blood vessels that provide nutrients and provide strength and resilienceto the skin. Smooth muscle controls both blood vessel diameterand hair position. Neural tissue supports and monitors sensory receptors in the skin

5-5

2 Distinct Layers

A layer of stratified squamous epithelium called the epidermis. A deeper layer of dense irregular connective tissue called the dermis.

deep to the dermis is a layer of areolar and adipose connective tissue called the subcutaneous layer, or hypodermis

6

Page 3: Integumentary system

3

7

5-8

Thick Skin

Thick epidermis is found on the palms of the hands, the soles of the feet, and corresponding surfaces of the fingers and toes. All five epidermal strata occur in thick skin.

5-9

Thin Skin

Thin epidermis covers most of the body.Lacks the stratum lucidum

Has only four specific layers. Contains the following accessories: hair follicles, sebaceous glands, and sweat glands.

Page 4: Integumentary system

4

5-10

Functions of Skin

protectionprevention of water losstemperature regulationmetabolic regulationimmune defensesensory receptionexcretion

5-11

Skin Color

Hemoglobin is an oxygen-binding protein present in red blood cells. Upon binding with oxygen, hemoglobin exhibits a bright red color.Melanin is a pigment produced and stored in cells called melanocytes.

the two types of melanin occur in various yellow, reddish, tan, brown, and black shades

Carotene comes primarily from diet.

5-12

Friction Ridges

Found on the fingers, palms, soles, and toes. Formed from large folds and valleys of both dermal and epidermal tissue.Help us grasp objects, and they Increase friction so that items do not slip easily from our hands. Our feet do not slip on the floor when we walk.

Page 5: Integumentary system

5

5-13

Friction Ridges

Friction ridges can leave noticeable prints on touched surfaces.Each individual has a unique pattern of friction ridges.Fingerprints have become a valuable tool for law enforcement in identifying individuals.

5-14

Skin Markings

Nevus (mole) Freckles Hemangioma

capillary hemangiomas (“strawberry-colored birthmarks”) cavernous hemangiomas (“port-wine stains”)

5-15

Layers of the Dermis

Composed of cells of the connective tissue proper and primarily of collagen fibers, although both elastic and reticular fibers are also present. Other components of the dermis are blood vessels, sweat glands, sebaceous glands, hair follicles, nail roots, sensory nerve endings, and muscular tissue.

Page 6: Integumentary system

6

5-16

2 Major Regions of Dermis

Superficial papillary layer Deeper reticular layer

5-17

Lines of Cleavage

Tension lines in the skin identify the predominant orientation of collagen fiber bundles. Clinically and surgically significant because cuts can result in slow healing and increased scarring.

18

Page 7: Integumentary system

7

5-19

Innervation and Blood Supply The dermis has extensive innervation. Monitor sensory receptors in the dermis and epidermis, and control both blood flow and gland secretion rates. Tactile corpuscles and tactile (Merkel) cells perceive touch sensations, and work with a variety of other sensory nerve endings in the skin. This rich innervation allows us to be very aware of our surroundings and to differentiate among the different kinds of sensory signals from receptors in the skin.

5-20

Nails

Scalelike modifications of the epidermis that form on the dorsal surfaces of the tips of the fingers and toes. Protect the exposed distal tips and prevent damage or distortion during jumping, kicking, catching, or grasping. Hard derivatives formed from the stratum corneum layer of the epidermis.

21

Page 8: Integumentary system

8

5-22

Hair

Found almost everywhere on the body except the palms of the hands, the sides and soles of the feet, the lips, the sides of the fingers and toes, and portions of the external genitalia. Most of the hairs on the human body are on the general body surface rather than the head.

23

24

Page 9: Integumentary system

9

5-25

3 Kinds of Hair

During our lives, we produce three kinds of hair:

lanugovellus terminal hair

5-26

Functions of Hair

Protection Heat retention Prevents the loss of conducted heat from the scalp to the surrounding air Facial expressionSensory reception Visual identification Chemical signal dispersal

5-27

Hair Color

Result of the synthesis of melanin in the matrix adjacent to the papillae. Variations in hair color reflect genetically determined differences in the structure of the melanin. Environmental and hormonal factors Age

Gray hair

Page 10: Integumentary system

10

5-28

Hair Growth and Replacement

Sometimes hair loss may be temporary as a result of one or more of the following factors: exposure to drugs, dietary factors, radiation, high fever, or stress. Thinning of the hair, called alopecia can occur in both sexes, usually as a result of aging.

5-29

Exocrine Glands of the Skin

Sweat (sudoriferous) glands produce a watery solution that performs several specific functions.

merocrine (eccrine) sweat glands apocrine sweat glands

Sebaceous glands produce an oily material that coats hair shafts and the epidermal surface.

30

Page 11: Integumentary system

11

31

5-32

Other Integumentary Glands

Ceruminous glands Mammary glands

modified apocrine sweat glands

5-33

Burns

Major cause of accidental death, primarily as a result of their effects on the skin. Usually caused by heat, radiation, harmful chemicals, sunlight, or electrical shock. The immediate threat to life results primarily from fluid loss, infection, and the effects of burned, dead tissue. Burns are classified according to the depth of tissue involvement.

Page 12: Integumentary system

12

5-34

Classification of Burns

First- and second-degree burns are called partial-thickness burns. Third-degree burns are called full-thickness burns.

first-degree burns involve only the epidermis and are characterized by redness, pain, and slight edema

an example is sunburn

5-35

Classification of Burns

Second-degree burns involve the epidermis and part of the dermis. The skin appears red, tan, or white, and is blistered and painful.

An example is a scald.

5-36

Classification of BurnsThird-degree burns involve the epidermis, dermis, and subcutaneous layer, which are often destroyed. Regeneration may occur from the edge only, due to the absence of dermis.Skin grafting is required to prevent abnormal connective tissue fibrosis and disfigurement. Dehydration is a major concern because the entire portion of skin has been lost, and water cannot be retained. Must be aggressively treated for dehydration.

Page 13: Integumentary system

13

5-37

Aging of the Integument

Skin repair processes take longer due to reduced number and activity of stem cells. Skin forms wrinkles and becomes less resilient. Skin’s immune responsiveness is diminished.Skin becomes drier due to decreased sebaceous gland activity.Altered skin and hair pigmentation.

5-38

Aging of the Integument

Sweat production diminishes. Blood supply to the dermis is reduced leading to impaired thermoregulation. Hair thinning and loss. Integumentary production of vitamin D3diminishes. Development of skin cancers.

5-39

Skin Cancer

The most common type of cancer. The greatest risk factor is exposure to UV rays of the sun. The highest incidence is in people who have had severe sunburns, especially as children.