Chapter 7 Integumentary System and Body Temperature

Integumentary System

a complex organ that performs many functions

Integument or Cutaneous Membrane

the skin - considered an organ - largest organ in the body

Functions of the Integumentary System

Serves as mechanical barrier

Protects internal structures

Participates in the immune response

Acts as a gland for vitamin D synthesis

Performs excretory function

Performs sensory role

Helps regulate body temperature

Acts as a gland for vitamin D synthesis

Integumentary System

Layers of Integumentary System

Epidermis

Dermis

Subcutaneous

Accessory structures

Dermatology

The study of skin and skin disorders

Epidermis

the thin outer layer of the skin - composed of stratified squamous epithelium

Contains the stratum germinativum and the stratum corneum

Epidermis

Epidermal layer that forms the bathtub ring

Stratum Corneum

Layer underneath the Epidermis

Dermis

Stratum germinativum (deeper)

layer of epidermis that continuously produces millions of cells every day - cells continuously dividing and moving toward surface

Stratum corneum (surface layer)

surface layer of the epidermis that makes up most of the epidermal thickness - composed of dead, flattened cells that slough off

Keratinization

the protein keratin makes skin cells hard, flat, and water resistant

Dermis

lies under and supports epidermis - the largest portion of the skin - sits on the subcutaneous layer (hypodermis) - composed of dense fibrous tissue - contains numerous collagen and elastic fibers surrounded by a gel-like substance

Accessory Structures embedded within the Dermis

the hair, nails and certain glands

layer of skin that contains the blood vessels, nerves, and sensory receptors

Dermis

Sensory Receptors (Dermis)

detect pain, temperature, pressure, touch

Subcutaneous Layer

"hypodermis" - dermis lies on this layer - not considered part of the skin - composed of loose and adipose tissue

Layer that insulates the body from extreme temperature changes and anchors the skin to the underlying structures

Subcutaneous Layer

Hypodermis

Subcutaneous Layer

Another name for the skin

Integument

Striae

stretch marks

Dander

dead sloughed cells

Dandruff

forms when dander is clumped together by oil on the skull

The Skin Tells a Story

Reflects disease processes of the body

Drug reactions reflected in skin changes

The skin responds to chronic irritation

The skin mirrors your stress level

Desquamation and exfoliation refer to this epidermal layer

Stratum Corneum

Another name for the cutaneous membrane

Integument

This epidermal layer forms corns and calluses

Stratum Corneum

Skin Color

Determined by genes, physiology, and sometimes pathology

Melanin

Dark pigment - Secreted by melanocytes in the epidermis

Melanocyte malfunctions

Albinism, vitiligo, moles

Albinism

Condition that occurs if melanocytes completely fail to secrete melanin; the skin, hair, and iris (colored part of eye) are white.

Vitiligo

Condition that involves loss of pigment in certain areas of the skin - creating patches of white skin

Moles

Example of melanin that becomes concentrated in local areas

Carotene

Yellow pigment- presence of melanin overshadows it's tint in most people

Blushing

Blood vessel dilation

Pallor

Blood vessel constriction

Cyanosis

"bluish tint" - Poor oxygenation

Jaundice

"yellowing" - Bilirubin deposition

Bronzing

Melanin overproduction

Ecchymosis

Black and blue bruising

Functions of Hair

Detect insects, protect eyes, keep dust out of lungs

Hormones affect growth

Melanin influencescolor

Hair arises in epidermis

Cosmetic role

Hairless Body Parts

Palms of hands, soles of feet, lips, nipples and parts of the external reproductive organs

Functions of Nails

Made up of free edge, nail body, and nail root

Protect tips of fingers and toes from injury

Conditions affected by oxygenation of blood supply, trauma, and nutritional deficiencies

Lunula

Half-moon shaped - shows nail growth - located at the base of nail

Hirsutism

Excessive hair growth - "shaggy" or hairy

Arrector Pili

group of smooth muscle cells attached to hair follicle - Contraction of these muscles causes the hairs to stand on end- goose bumps.

Alopecia

Loss of hair

Sebaceous glands

Oil glands - associate with hair follicles - found in all areas of the body that have hair - secrete sebum

Sudoriferous

Sweat glands- located in Dermis

Vernix Caseosa

Covering that babies are born with that resembles cream cheese - protects the skin of the fetus from macerating effects of amniotic fluid

Apocrine Glands

Usually associated with hair follicles; more active at puberty

Eccrine glands:

Critical for temperature regulation

Types of modified sweat glands

Mammary glands and Ceruminous glands

Mammary glands

Secrete milk

Ceruminous glands

Secrete ear wax (cerumen)

Core temperature

The inner parts of the body

Shell temperature

The surface areas of the body

Thermoregulation

Balance of heat production and heat loss

Metabolism

Basis of body temperature

Heat Production produced by _________, _________, and _______ ________?

muscles, the liver, and endocrine glands

_________ disperses heat throughout the body

Blood

Heat Production is affected by _______ __________, _________ and __________ __________?

Food consumption, hormones, disease, and physical activity

Heat Loss in Skin (___%), lungs, and excretory products (___%)

80% and 20%

Types of Heat Loss

Radiation

Conduction

Convection

Evaporation

Radiation

heat is lost from a warm object (the body) to the cooler air surrounding the warm object - "losses heat it cold room"

Conduction

the loss of heat from a warm body to a cooler object in contact with the warm body - "sitting on ice block"

Convection

loss of heat by air currents moving over the surface of the skin - "fan moves air across skin, constantly removing layer of heated air next to the body"

Evaporation

when a liquid becomes a gas - "when alcohol is rubbed on the skin, it evaporates and cools the skin"

Burns are classified by _______?

Depth

Partial thickness burns

First-degree and Second-degree burns

First-degree

red, painful, slightly edematous (swollen) - only epidermis is involved - "sunburn"

Second-degree

involves damage to both epidermis and dermis - redness, pain, edema, blister formation - great damage may cause red, white or tan skin

Full-thickness burn

Third-degree

Third-degree

both epidermis and dermis are destroyed - painless due to sensory receptors being destroyed -

Eschar

dead burned tissue that forms thick, inflexible, scab like layer over burned surface - Acts like a tourniquet - Breeds bacteria - Secretes toxins

Burn victims are at risk for _______ ______ and ________?

fluid imbalances and infection