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Chapter 6Lecture

PowerPoint

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2401Anatomy and Physiology I

Chapter 6

Susan Gossett

sgossett@parisjc.edu

Department of Biology

Paris Junior College

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Hole’s Human Anatomyand Physiology

Twelfth Edition

Shier Butler Lewis

Chapter 6

Integumentary System

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6.1: Introduction

• Two or more kinds of tissues grouped together and performing specialized functions constitutes an organ.

• The skin and its various structures make up the integumentary system.

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6.2: Skin and Its Tissues

• Composed of several tissue types• Maintains homeostasis• Protective covering• Retards water loss• Regulates body temperature• Houses sensory receptors• Contains immune system cells• Synthesizes chemicals • Excretes small amounts of wastes

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Skin Cells

• Help produce Vitamin D needed for normal bone and tooth development

• Some cells (keratinocytes) produce substances that stimulate development of some white blood cells

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Layers of Skin

• Epidermis• Dermis• Subcutaneous layer

• A.k.a hypodermis• Beneath dermis

Stratifiedsquamousepithelium

Dense irregularconnectivetissue

Adipose tissue

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© The McGraw-Hill Companies, Inc./Al Telser, photographer

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(a)

Hair shaft

Epidermis

Hair follicle

(b)

Sebaceous gland

Dermis

Sweat

Epidermis

Dermis

Hair shaft

Sweat gland pore

Capillary

Stratum corneum

Stratum basale

Dermal papilla

Arrector pili muscle

Lamellated (Pacinian) corpuscle

Basement membrane

Sebaceous gland

Hair follicle

Sweat gland

Nerve cell process

Adipose tissue

Blood vessels

Muscle layer

Sweat gland duct

Subcutaneouslayer

TTactile (Meissner’s) corpuscle

Epidermis

• Lacks blood vessels• Keratinized• Thickest on palms and

soles (0.8-1.4mm)• Melanocytes provide melanin• Rests on basement membrane• Stratified squamous epithelia

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b: © Victor Eroschenko

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Epidermis

There are five (5) layers of the epidermis:• Stratum corneum• Stratum lucidum (only in thick skin – palms, soles)• Stratum granulosum• Stratum spinosum• Stratum basale

Stratum corneum

Stratum lucidum

Stratum granulosum

Stratum spinosum

Stratum basale

Basementmembrane

Dermis

Dermal papilla

(a) (b)

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b: © The McGraw-Hill Companies, Inc./Al Telser, photographer

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Epidermis

• Genetic Factors• Varying amounts of melanin• Varying size of melanin granules• Albinos lack melanin

• Environmental Factors• Sunlight• UV light from sunlamps• X-rays• Darkens melanin

• Physiological Factors• Dilation of dermal blood vessels• Constriction of dermal blood vessels• Accumulation of carotene• Jaundice

• Heredity and environment determine skin color

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6.1 Clinical Application

Tanning and Skin Cancer

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Dermis

• Contains dermal papillae

• Binds epidermis to underlying tissues• Irregular dense connective tissue

• On average 1.0-2.0mm thick

• Muscle cells

• Nerve cell processes• Specialized sensory receptors

• Blood vessels

• Hair follicles

• Glands

(a)

Sweat

Epidermis

Dermis

Hair shaft

Sweat gland pore

Capillary

Stratum corneum

Stratum basale

Dermal papilla

Arrector pili muscle

Lamellated (Pacinian) corpuscle

Basement membrane

Sebaceous gland

Hair follicle

Sweat gland

Nerve cell process

Adipose tissue

Blood vessels

Muscle layer

Sweat gland duct

Subcutaneouslayer

Tactile (Meissner’s) corpuscle

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Dermis

• Papillary layer• Thin• Superficial• Dermal papillae here

• Reticular layer• 80% of dermis• Cleavage, tension or Langer’s lines are here

• There are actually two (2) layers to the dermis:

(a)

Papillary layer

Reticular layer

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Subcutaneous Layer

• A.k.a hypodermis

• Loose connective tissue and Adipose tissue

• Insulates

• Major blood vessels present

(a)

Sweat

Epidermis

Dermis

Hair shaft

Sweat gland pore

Capillary

Stratum corneum

Stratum basale

Dermal papilla

Arrector pili muscle

Lamellated (Pacinian) corpuscle

Basement membrane

Sebaceous gland

Hair follicle

Sweat gland

Nerve cell process

Adipose tissue

Blood vessels

Muscle layer

Sweat gland duct

Subcutaneouslayer

Tactile (Meissner’s) corpuscle

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6.3: Accessory Structures of the Skin

• Accessory structures of the skin originate from the epidermis and include:

• Hair follicles• Nails• Skin glands

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Hair Follicles

• Epidermal cells

• Tube-like depression

• Extends into dermis

• Three (3) parts:• Hair root• Hair shaft• Hair papilla

• Dead epidermal cells

• Melanin• Arrector pili muscle

(a)

Hair shaft

Pore

Hair root(keratinizedcells)

Arrector pilimuscle

Sebaceousgland

Hair follicle

Region ofcell division

Hair papilla

Eccrinesweat gland

Dermal blood vessels

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Nails

• Protective coverings

• Three (3) parts:• Nail plate• Nail bed

• Lunula

Nail bed Nail plateLunula

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6.2 Clinical Application

Hair Loss

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Sebaceous Glands

• Usually associated with hair follicles

• Holocrine glands

• Secrete sebum (oil)

• Absent on palms and soles

Hair

Sebaceousgland

Hair follicle

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© Per H. Kjeldsen

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Sweat Glands

• A.k.a sudoriferous glands

• Widespread in skin

• Originates in deeper dermis or hypodermis

• Eccrine glands

• Apocrine glands

• Ceruminous glands

• Mammary glands

Dermalpapilla

Sebaceousgland

Duct

Hair shaft

Hairfollicle

Eccrinesweatgland

Apocrinesweatgland

Pore

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6.3 Clinical Application

Acne

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6.4: Regulation of Body Temperature

• Regulation of body temperature is vitally important because even slight shifts can disrupt metabolic reactions.

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Regulation of Body Temperature

If body temperaturecontinues to drop,control center signalsmuscles to contractinvoluntarily.

too high

too low

Normal bodytemperature37°C (98.6°F)

Control centerHypothalamusdetects the deviationfrom the set point andsignals effector organs.

Control centerHypothalamusdetects the deviationfrom the set point andsignals effector organs.

StimulusBody temperature risesabove normal.

EffectorsDermal blood vesselsdilate and sweat glandssecrete.

ResponseBody heat islost to surroundings,temperature drops towardnormal.

EffectorsDermal bloodvessels constrictand sweat glandsremain inactive.

EffectorsDermal bloodvessels constrictand sweat glandsremain inactive.

ResponseBody heat is conserved,temperature rises toward normal.

StimulusBody temperaturedrops below normal.

ReceptorsThermoreceptorssend signals to thecontrol center.

ReceptorsThermoreceptorssend signals to thecontrol center.

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Heat Production and Loss

• Heat is a product of cellular metabolism• The most active body cells are the heat producers and include:

• Skeletal muscle• Cardiac muscle• Cells of certain glands such as the liver

• The primary means of heat loss is radiation• Also there is conduction, convection and evaporation

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Problems in Temperature Regulation

• Hyperthermia – abnormally high body temperature

• Hypothermia – abnormally low body temperature

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6.4 Clinical Application

Elevated Body Temperature

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6.5: Healing of Wounds and Burns

• Inflammation is a normal response to injury or stress.• Blood vessels in affected tissues dilate and become more permeable, allowing fluids to leak into the damaged tissues.• Inflammed skin may become:

• Reddened • Swollen • Warm • Painful

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(a) (b)

(f) (g)

(c) (d) (e)

Scartissue

Fibroblasts

Scartissue

Blood cells

Site of injury

Scab

Bloodclot

Scab

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Types of Burns

• First degree burn – superficial, partial-thickness

• Second degree burn – deep, partial-thickness

• Third degree burn – full-thickness• Autograft• Homograft• Various skin substitutes

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Rule of Nines for AdultsCopyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.

Anteriortrunk18%

Posteriortrunk18%

Anterior upperextremities 9%

Posterior upperextremities 9%

Posterior lowerextremities 18%

Perineum 1%

Anterior andposterior upper

extremities18%

Anterior andposterior lower

extremities36%

100%

Anterior andposterior trunk

36%

Anterior and posterior head and neck9%

Anterior headand neck 41/2%

Posterior headand neck 41/2%

Anterior lowerextremities 18%

9% 9% 9% 9%

41/2%

41/2% 41/2% 41/2% 41/2%

41/2%

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6.6: Lifespan Changes

• Skin becomes scaly• Age spots appear• Epidermis thins• Dermis becomes reduced• Loss of fat• Wrinkling• Sagging• Sebaceous glands secrete less oil

• Melanin production slows• Hair thins• Number of hair follicles decreases• Nail growth becomes impaired• Sensory receptors decline• Body temperature unable to be controlled• Diminished ability to activate Vitamin D

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Important Points in Chapter 6:Outcomes to be Assessed

6.1: Introduction

Define organ, and name the large organ of the integumentary system.

6.2: Skin and Its Tissues

List the general functions of the skin.

Describe the structure of the layers of skin.

Summarize the factors that determine skin color.

6.3: Accessory Structures of the Skin

Describe the accessory structures associated with the skin.

Explain the functions of each accessory structure of the skin.

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Important Points in Chapter 6:Outcomes to be Assessed

6.4: Regulation of Body Temperature

Explain how the skin helps regulate body temperature.

6.5: Healing of Wounds and Burns

Describe the events that are part of wound healing.

Distinguish among the types of burns, including a description of healing with each type.

6.6: Lifespan Changes

Summarize lifespan changes in the integumentary system.

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Quiz 6

Complete Quiz 6 now!

Read Chapter 7.