Chapter 7
Integumentary System
and Body Temperature
Elsevier items and derived items © 2007, 2003, 2000 by Saunders, an imprint of Elsevier Inc.
Slide 1
Introduction
• The integumentary system includes the skin,
which covers the body, protects the internal
organs, and plays an important role in the
regulation of body temperature.
Slide 2
Structures: Organs of the
Integumentary System
• The integumentary system includes the skin,
accessory structures, and subcutaneous tissue
beneath the skin.
Slide 3
Structures: Organs of the
Integumentary System - cont’d
• Skin
– The skin is called the cutaneous membrane.
– The skin has two layers, an outer layer called the
epidermis and an inner layer called the dermis.
– The epidermis has five layers. The stratum
germinativum is the layer in which cell division takes
place. The new cells produce keratin (waterproofing)
and die as they are pushed toward the surface. The
outer layer is the stratum corneum and consists of
flattened, dead, keratinized cells.
Slide 4
Structures: Organs of the
Integumentary System - cont’d
• Skin—cont’d
– The dermis lies on the subcutaneous tissue.
– Skin color is determined by many factors: some
genetic, some physiologic, and some due to disease.
Melanin causes skin to darken. Carotene causes skin
to appear yellow. The amount of blood in the skin
affects skin color (e.g., flushing) as does the
appearance of abnormal substances such as
bilirubin (jaundice) and a low blood oxygen content
(cyanosis).
Slide 5
Structures: Organs of the
Integumentary System - cont’d
• Accessory Structures of the Skin
– Hair is unevenly distributed over the skin. The location
of the hair determines its function. Eyebrows and
eyelashes protect the eyes from dust and perspiration.
– The main parts of a hair are the shaft and root.
– Hair color is determined by the amount and type of
melanin.
– Nails are thin plates of stratified squamous epithelial
cells that contain a hard form of keratin.
– There are two major exocrine glands in the skin:
sebaceous glands and sweat glands.
Slide 6
Structures: Organs of the
Integumentary System - cont’d
• Accessory Structures of the Skin—cont’d
– The sebaceous glands (oil glands) secrete sebum. The
sebum lubricates hair and skin. In the fetus, these
glands secrete vernix caseosa, a cheeselike substance
that coats the skin of a newborn.
– The two types of sweat glands (sudoriferous glands)
are the apocrine glands and the eccrine glands. The
eccrine sweat glands play a crucial role in temperature
regulation.
– The mammary glands (which secrete milk) and the
ceruminous glands (which secrete ear wax) are
modified sweat glands.
Slide 7
Structures: Organs of the
Integumentary System - cont’d
• Subcutaneous Tissue
– Subcutaneous tissue anchors the dermis to
underlying structures.
– Subcutaneous tissue acts as an insulator; it
prevents heat loss.
Slide 8
Regulation of Body Temperature
• Heat Production
– Heat produced by metabolizing cells constitutes
the body temperature.
– Most of the heat is produced by the muscles and
the liver.
• Heat Loss
– Most of the heat (80%) is lost through the skin.
– Heat loss occurs through radiation, conduction,
convection, and evaporation.
Slide 9
Regulation of Body Temperature - cont’d
• Heat Loss—cont’d
– Normal body temperature is set by the body’s
thermostat in the hypothalamus.
– Heat is lost through sweating and vasodilation.
Heat is conserved by vasoconstriction and
produced by shivering.
Slide 10
When Skin Is Burned
• Physiological Effects
– Short-term effects: fluid and electrolyte losses,
shock, inability to regulate body temperature,
infection
– Long-term effects: scarring, loss of function, and
cosmetic and emotional problems
• Classification of Burns
– Classified according to the thickness of the burn
(partial, full); also first, second, and third degree.
– The rule of nines is a way to evaluate burns.
Slide 11
Introduction
• Tissues are groups of cells similar to each
other in structure and function.
• Membranes are thin sheets of tissue that
cover surfaces, line body cavities, and
surround organs.
Slide 12
Types of Tissue
• Epithelial Tissue Types
– Epithelial tissue covers surfaces, lines cavities, and
engages in secretion/absorption and protective
functions.
– Epithelial tissue is classified according to cell shape
(squamous, cuboidal, and columnar) and layers
(simple and stratified).
– The types and functions are summarized in Table 61.
Slide 13
Types of Tissue - cont’d
• Connective Tissue
– The primary function of connective tissue is to bind
together the parts of the body. Other functions
include support, protection, fat storage, and transport
of substances.
– Connective tissue has an abundant intercellular matrix
that fills spaces between cells. The intercellular matrix
may be liquid, gel-like, or hard. The matrix often
contains protein fibers that are secreted by the cells.
– There are three types of loose connective tissue:
areolar, adipose, and reticular.
Slide 14
Types of Tissue - cont’d
• Connective Tissue—cont’d
– Dense fibrous connective tissue forms tendons, ligaments,
capsules, and fascia, and is found in the skin (dermis).
– Types of cartilage include: hyaline, elastic, and
fibrocartilage.
– Bone (osseous tissue) is connective tissue formed by
osteocytes. Bone cells have a hard intercellular matrix that
includes collagen, calcium salts, and other minerals.
– Blood and lymph are types of connective tissue that have a
watery intercellular matrix.
Slide 15
Types of Tissue - cont’d
• Nervous Tissue
– Nervous tissue is found in the peripheral nerves,
brain, and spinal cord.
– The two types of nervous tissue are neurons,
which transmit electrical signals, and neuroglia,
which support and take care of the neurons.
• Muscle Tissue
– Muscle cells contract, thereby causing movement.
– The three kinds of muscle are skeletal, smooth,
and cardiac.
Slide 16
Tissue Repair
• Tissue Repair by Regeneration
– Replacement of tissue by cells that undergo
mitosis
• Tissue Repair by Fibrosis
– Formation of scar tissue
Slide 17
Membranes
• Epithelial Membranes
– The cutaneous membrane is the skin.
– Mucous membranes are epithelial membranes that line all
body cavities that open to the exterior of the body.
– Serous membranes are epithelial membranes that line the
ventral body cavities, which are not open to the exterior of
the body.
– Serous membranes form two layers: a parietal layer that lines
the wall of the cavity and a visceral layer that covers the
outside of an organ.
– The three serous membranes are the pleura, the
pericardium, and the peritoneum.
Slide 18
Membranes - cont’d
• Connective Tissue Membranes
– Synovial membranes are connective tissue
membranes.
– Other connective tissue membranes are listed in
Table 6-3.
Slide 19