Transcript Integumentary System - Gantner Avenue Elementary School

Integumentary System
CHAPTER 4
Body membranes
 Cover surface
 Line body cavities
 Form protective sheets around organs
 2 major categories:
 1. epithelial membranes
 2. connective tissue membranes
Epithelial Membranes
 Cutaneous membrane(skin)
 Mucous membranes
 Serous membranes
 Even though we call them epithelial- they are not
only composed of epithelial tissue
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They are epithelial tissue and connective tissue
Cutaneous Membrane
 Skin
 Superficial epidermis is composed of a keratinizing
stratified squamous epithelium
 Underlying dermis is dense fibrous connective tissue
 Exposed to the air and is a dry membrane
Mucous membrane
 Composed of epithelium rest on a loose connective tissue
membrane called lamina pretrial
 Lines all body cavities that are open to the exterior
 Ex: lines the hollow organs of the respiratory system,
digestive system, urinary system, and reproductive tracts
 Most contained stratified squamous epithelium or simple
columnar epithelium.
 Wet or moist membranes that are bathed in secretions
 Adapted for absorption or secretion.
Serous membranes
 Serosa membrane
 Composed of a layer of simple squamous epithelium
resting on a thin layer or areolar connective tissue.
 Line body cavities that are closed to the exterior.
 Occur in pairs
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Parietal layer lines a specific portion of the wall of the ventral body
cavity
Parietal layer folds on itself and forms the visceral layer
Visceral layer- cover the outside of the organs in the cavity
Serous membranes
 Serous layers are separated by a thin, clear fluid called
serous fluid
 Serous fluid is secreted by membranes
 Serous fluid allows organs to slide easily across the cavity
walls of one another without friction as they carry out
routine functions.
 Serosa lining abdominal cavity- peritoneum
 Serosa around the lungs- pleura
 Serosa around the heart- pericardium
Connective tissue membranes
 Composed of soft areolar connective tissue
 Contain no epithelial cells at all
 Line fibrous capsules of surrounding joints
 Provide a smooth surface between joints
 Secrete lubricating fluid
 Line small sacs of connective tissue called bursae and
tubelike tendon sheaths
Basic Skin Functions
 Keeps water and precious molecules in.
 Keeps water and bacteria out.
 The capillary network and sweat glands offer regulation of
heat loss.
 Insulates and cushions the deeper organs.
 Protects the entire body from mechanical damage and UV
radiation.
 Houses our cutaneous sensory receptors. (part of the
nervous system)
Structure of the skin
 The skin is composed of two kinds of tissue
Stratified Squamous Epithelium makes up the
EPIDERMIS. (This epithelium is capable of
keratinizing.)
2. Dense Connective Tissue makes up the DERMIS.
 These two layers are firmly connected .
1.
 A layer of Adipose Tissue lies beneath the skin and is called
the subcutaneous tissue, or HYPODERMIS. It connects
the skin to underlying organs
EPIDERMIS
 The epidermis is composed of 5 layers which are avascular
called strata.
 The cells of the epidermis are keratinocytes – they produce
the fibrous protein keratin.
 The deepest layer of the epidermis is the STRATUM
BASALE, which is the only layer that receives nourishment
by diffusion from the dermis.
 The Stratum Basale undergoes constant division, pushing
new cells upward to become part of the next layer.
Layers of the epidermis
5. STRATUM BASALE
4. STRATUM SPINOSUM
3. STRATUM GRANULOSUM
2. STRATUM LUCIDUM
1. STRATUM CORNEUM
 The cells become flatter and increasingly full of keratin as
they move away from the dermis.
 The accumulation of water repellent keratin, and increasing
distance form the blood and nutrient supply ultimately kills
the cells.
dermis
 The dermis is a strong stretchy envelope that helps hold
your body together. It varies in thickness in different
locations of the body.
Layers of the dermis
1. Papillary Layer
2. Reticular Layer
 The papillary layer lies just below the epidermis. It is
uneven and has fingerlike projections from its superior
surface called DERMAL PAPILLAE. The Dermal Papillae
contains small blood vessels called capillary loops, pain
receptors, and touch receptors.
 The reticular layer is the deepest layer of the skin. It
contains blood vessels, sweat and oil glands, and pressure
receptors.
 Collagen and Elastic fibers are found throughout the dermis
and are responsible for its toughness.
Skin color
 Amount and kind (yellow, reddish brown, or black)
of melanin in the epidermis
 Amount of carotene deposited in the stratum
corneum and subcutaneous tissue
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Carotene is orange-yellow pigment found in carrots and other
yellow-orange vegetables
 Amount of oxygen bound to hemoglobin in the
dermal blood vessels.
Skin appendages
 1. Cutaneous Glands
(Sebaceous Glands and Sweat
Glands)
 2. Hair and Hair Follicles
 3. Nails
Skin appendages
1 Cutaneous Glands
 The cutaneous glands are all exocrine glands that secrete
their secretions to the skins surface via ducts. They fall into
2 groups:
 A. SEBACEOUS GLANDS
 B. SWEAT GLANDS
Sebaceous glands
 A. Sebaceous Glands (oil glands) – their ducts usually
empty into a hair follicle, but some open directly onto the
skin. These glands produce SEBUM. ( a mixture of an oily
substance and fragmented cells)
 Sebum keeps the skin soft and moist and prevents the hair
from becoming brittle. It contains chemicals that kill
bacteria.
Sweat glands
 B. Sweat glands – are found all over the body, there are two
main types.
1. Eccrine Glands produce SWEAT which reaches the skins
surface via a duct called a PORE.
 Eccrine glands are an important and highly efficient factor
in heat regulation. They are supplied with nerve endings
which sense internal and external temps.
2. Apocrine Glands
 Usually confined to the axillary and genital areas.
Skin appendages
2. Hair and Hair Follicles
 Today hairs only serve a few minor functions (eyelashes,
nose hairs)
 A HAIR is flexible epithelial structure produced by a HAIR
FOLLICLE
 The part of the hair enclosed in the follicle is called the
ROOT.
 Each hair consists of a central core called the MEDULLA
surrounded by a bulky CORTEX which is surrounded by
the CUTICLE.
SKIN Appendages
3. Nails
 Nails are a scale like modification of the epidermis that is
similar to a hoof or claw of other animals.
 Nails have a free edge, a body, and a root which imbedded
in the skin
 They are transparent and nearly colorless but appear pink
because of the blood supply in the dermis below.
Homeostatic Imbalance
 Overexposure to the sun
 The appearance of aging skin
 Bed Sores
 Blushing- Turning Blue
 Acne
 Allergies and Infections
 Burns
 Cancer
Homeostatic imbalances of skin
 Infections and allergies
 Burns
 Skin cancer
Athletes Foot
 Itchy, red, peeling condition of the skin
 Appears between the toes
 Results from a fungus infection
 Tinea pedis
Boils and Carbuncles
 Inflammation of hair follicles and sebaceous glands
 Common in dorsal neck
 Carbuncles- composite boils typically caused by a
bacteria infection
Cold Sores
 Fever blisters
 Small, fluid-filled blisters that itch and sting
 Caused by a herpes simplex infection
 Virus localizes in a cutaneous nerve where it remains
dormant until activated by emotions upset, fever, or UV
radiation
 Usually occur around the lips and oral mucosa of the
mouth
Contact Dermatitis
 Itching, redness, swelling of the skin
 Progressing to blistering
 Caused by exposure of the skin to chemicals that
provoke allergic responses in sensitive individuals
Impetigo
 Pink, water-filled, raised lesions (commonly around
the mouth and nose)
 Develop a yellow crust and eventually rupture
 Caused by a highly contageous staphlycoccus
infection
 Common in elementary school-ages children
Psorasis
 Chronic condition
 Characterized by reddened epidermal lesions covered
with dry, silvery scales
 May be disfiguring when severe
 Cause is unknown: may be hereditary in some cases
 Attacks often triggered by trauma, infection, hormonal
changes, and stress
Burns
 Skin is only as thick as a paper towel
 When skin is severely damages, nearly every body system
suffers
 Metabolism accelerates or may be impaired
 Changes in the immune system occur
 Cardiovascular system may falter
 Burn- tissue damage and cell death caused by intense
heat, electricity, UV radiation (sunburn), certain
chemicals (such acids)
Burns
 When skin is burned and its cells destroyed, two life-
threatening problems result.
 1. body loses its prescious supply of fluids containing
proteins and electrolytes as these seem from the
burned surfaces
 2. dehydration and electrolyte imbalance follow- this
can lead to a shutdown of kidneys and circulatory
shock
Rule of the nines
 Divides the body into 11 areas, each counts for 9
percent of the total body surface area
 Additional 1% is accounted for by the area
surrounding the genitals
 Volume of fluid lost can be estimated indirectly by
determining how much of the body surface is burned
by using this rule.
Developmental aspects of skin and body
membranes
 During the fifth and sixth month of fetal development the
infant is covered with a downy type of hair called lanugo.
 Lanugo has usually been shed by birth.
 When a baby is born the skin is covered with vernix
caseosa
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White, cheesy-looking substance
Produced by sebacous glands
Protects the baby’s skin while it is floating in water-filled sac inside
the mother
Newborn skin is very thin and you can see blood vessels through it
Developmental aspects of skin and body
membranes
 Milia- white spots that appear on the baby’s nose and
forehead
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Accumulations in the sebaceous glands
Usually disappear by 3 weeks after birth
 During adolescence skin and hair become more oily
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Sebaceous glands are activated
Acne may appear
Acne usually subsides in early adulthood and skin reaches optimal
appearance when we are in our 20s and 30s.
Visual changes appear in skin as we are exposed to sun, wind,
abrasion, chemicals, and other irritants
Developmental aspects of skin and body
membranes
 When skin pores become clogged with pollutants and
bacteria pimples, scales, and various kinds of
dermatitis(skin inflammation) become visible.
 During old age:
 Amount of subcutaneous tissue decreases which leads to
intolerance to cold
 Skin becomes dry
 Thinning skin make it more susceptible to bruising and other
types of injuries
 Sunlight causes loss of elasticity
Developmental aspects of skin and body
membranes
 Hair loses its luster as we age
 By age 50 the number of hair follicles has dropped by
1/3
 A bald man is not really hairless – he does have hairs
in the bald area
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The hair follicles have begun to degerate
Hairs are colorless and very tiny
These hairs are called vellus