Download The Integumentary System

The Integumentary System
The Integumentary System

Integument means covering.

Skin and its appendages make up the
integument system

It covers about 3,000 square inches of the
surface.

It is made up of hair, nails , sebaceous (oil)
glands, and Sudoferious (sweat) glands.
Functions of skin
 Skin is covering for the underlying, deeper, tissue ,
protecting them from dehydrations, injury, and germ
invasions.
 Skin helps regulate body temperature by controlling the
amount of heat loss .Evaporation of the water from the
skin , in the form of perspiration, rids the body of
excess heat.
 Skin helps manufacture vitamin D. The ultra violet light
on the skin is necessary for the first stages of vitamin D
formation.
Functions of The Skin
Continuation….
 Skin is the sight of many nerve endings. A square inch of
skin contains about 72 feet of nerves and hundreds of
receptors.
 Skin has tissues for the temporary storage of fat, glucose,
water, and salts such as sodium chloride. Most of the
substances are later contained observed and transferred
to other parts of the body.
 Skin is designed to screen out harmful
ultraviolet
contained by sunlight.
 Skin has special properties to absorb drugs and bad
toxins.
Structure of the Skin

The skin consists of two basic layers:
o
The epidermis or outermost or outermost
covering made of epithelial cells with no
blood vessels present
o The dermis or true skin is made of
connective tissue and is vascular
o ***The hypodermis isn’t really considered
but since its in the diagram I’ll go over it.
Epidermis
 Keratinized stratified squamous epithelium
 Four types of cells
 Keratinocytes – deepest, produces keratin (tough fibrous protein)
 Melanocytes - make dark skin pigment melanin
 Merkel cells – sensory receptors for touch
 Langerhans cells – macrophage which are effective in the defense
 Layers (from deep to superficial)
 Stratum basale or germinativum – single row of cells attached to




dermis; youngest cells
Stratum spinosum – spinyness is artifactual; tonofilaments (bundles
of protein) resist tension
Stratum granulosum – layers of flattened keratinocytes producing
keratin (hair and nails made of it also)
Stratum lucidum (only on palms and soles)
Stratum corneum – horny layer (cells dead, many layers thick)
Epithelium: layers (on left) and cell types (on right)
Dermis
 Corium, is the thicker, inner layer if the skin.
 It contains masses of connective tissues, collagen tissue
bands, elastic fibers, nerve endings, muscles, hair
follicles, oil and sweat glands, and fat cells.
 The thickness of the dermis varies over different parts of
the body for instance, the dermis is thicker over the soles
of the feet and the palms of the hands.
 There are many nerve receptor of different types of the
dermal layer.
 Blood vessels in the dermis aid in the regulation of body
temperature to maintain homeostasis.
*Dermis layers
*Dermal papillae
*
*
Hypodermis

Not considered apart of the Integumentary
system.

It lies under the dermis and called superficial
fascia.

It consists of loose connective tissues and
contains about ½ of the bodies stored half.
Derived from epidermis and dermis
Everywhere but palms, soles, nipples, parts of genitalia
*“arrector pili” is smooth muscle
*
Hair bulb:
epithelial cells
surrounding
papilla
Hair papilla
is connective
tissue________________
Skin appendages
 Derived from epidermis but extend into dermis.
 Include:
 Hair and hair follicles
 Sebaceous (oil) glands
 Sweat (sudoiferous) glands
 Nails
 Functions of hair
 Warmth – less in man than other mammals
 Sense light touch of the skin
 Protection - scalp
 Parts
 Root imbedded in skin
 Shaft projecting above skin surface
 Make up of hair – hard keratin
 Three concentric layers
 Medulla (core)
 Cortex (surrounds medulla)
 Cuticle (single layers, overlapping)
 Types of hair
 Vellus: fine, short hairs
 Intermediate hairs
 Terminal: longer, courser hair
 Hair growth: averages 2 mm/week
 Active: growing
 Resting phase then shed
 Hair loss
 Thinning – age related
 Male pattern baldness
 Hair color
 Amount of melanin for black or brown; distinct form of
melanin for red
 White: decreased melanin and air bubbles in the
medulla
 Genetically determined though influenced by hormones
and environment
Sebaceous (oil) glands
 Entire body except palms and soles
 Produce sebum by holocrine secretion
 Oils and lubricates
Sweat glands
 Entire skin surface
except nipples and
part of external
genitalia
 Prevent overheating
 500 cc to 12 l/day!
(is mostly water)
 Humans most
efficient (only
mammals have)
 Produced in
response to stress
as well as heat
Types of sweat
glands
 Eccrine or merocrine
 Most numerous
 True sweat: 99% water, some salts, traces of waste
 Open through pores
 Apocrine
 Axillary, anal and genital areas only
 Ducts open into hair follices
 The organic molecules in it decompose with time - odor
 Modified apocrine glands
 Ceruminous – secrete earwax
 Mammary – secrete milk
Nails

Of hard keratin

Corresponds to hooves and claws

Grows from nail matrix
Careers Associated with
Integumentary System
 Dermatologist- Annual salary of 279,000, Dermatologists are medical
doctors who deal with skin and skin aliments, the conduct skin
evaluations in order to determine how to best treat and prevent conditions
and diseases. Education: Undergraduate, 4 years of medical school,
residency programs (3-4 years)
 Plastic surgeon- Doctors who deal with replacing, repairing or
reconstructing various parts of the body, mostly facial features. Annual
salary of 300,000 to 791,510, Education: Complete up to medical school
requirements and then must complete residencies which takes longer
than other normal residencies.
 Allergist- Annual salary: 332,450, Specialist in diagnosis and treatment of
allergic diseases. Education: The first step towards becoming an allergist
is earning a medical degree, then two more years for specialization; the
final step is to earn certification from the board of allergy and
immunology.
Disorders of the Integumentary system
 Burns
 Threat to life
 Catastrophic loss of body fluids
 Dehydration and fatal circulatory shock
 Infection
 Types
 First degree – epidermis: redness (e.g. sunburn)
 Second degree – epidermis and upper dermis: blister
 Third degree - full thickness
 Infections
 Skin cancer
Burns
First-degree
(epidermis only; redness)
Second-degree
(epidermis and dermis,
with blistering)
Third-degree
(full thickness, destroying
epidermis, dermis, often part
of hypodermis)
Estimate by “rule of 9’s”
Critical burns
 Over 10% of the
body has thirddegree burns
 25 % of the body
has second-degree
burns
 Third-degree burns
on face, hands, or
feet
Tumors of the skin

Benign, e.g. warts

Cancer – associated with UV exposure (also skin aging)
 Aktinic keratosis - premalignant
 Basal cell - cells of stratum basale
 Squamous cell - keratinocytes
 Melanoma – melanocytes: most dangerous; recognition:
 A - Asymmetry
 B - Border irregularity
 C - Colors
 D - Diameter larger than 6 mm
Skin Cancer
Sqaumous cell carcinoma
Basal cell carcinoma
Melanoma