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Chapter 7
Structure & Function of Human Body
OBJECT IVES
Students should be able to:
• Understand and explain the difference between anatomy,
physiology, and pathophysiology.
• Define what determines a state of wellness as opposed to
illness.
• Describe the primary anatomical features and physiological
actions of the systems for movement & protection of the
body.
• Name common diseases or disorders associated with each
system.
• Describe the behaviors and actions for each body system
that promote health and prevent major diseases and
disorders.
Definitions
Anatomy:
= study of the form & structure of
an organism, such as the names
& locations of bones, muscles, & organs.
Anatomy comes from 2
words:
Ana which means “up
or apart”
Tomos which means
“to cut”
“The Anatomy Lesson of Dr Nicolaes
Tulp” by Rembrandt in 1632
Definitions
Physiology:
= study of the functions (how and why
something works) of the body’s structures.
Definitions
Disease:
= abnormal conditions in the body are called
diseases. When an abnormality occurs it is
referred to as a pathophysiology (patho =
disease).
Definitions
Pathophysiology:
= is the study of why diseases occur & how the
body changes in function in rx to diseases.
Definitions cont.
Etiology:
= study of the causes of diseases. Diseases have
a variety of causes. Ex’s: Bact, viruses,
hazards, & personal habits.
Signs:
• objective evidence of an illness
• Means health care professional
can observe them
Symptoms:
• Subjective
• cannot be directly observed by
health care professional but
are reported by patient
Definitions
Syndrome:
= not a precise disease but a group of related signs
& symptoms
Definitions cont.
Diagnosis:
• Name of the Disease or Syndrome
Diagnostic procedures:
• Tests performed to determine the diagnosis
Definitions cont.
Treatment
= Meds or procedures used to control or cure
the disease. Common treatments include
surgery, exercise, & special diets.
Definitions cont.
Prognosis
• Prediction of possible outcome of the
disease & potential for recovery.
Prevention
• Behaviors that promote health & prevent
disease
Definitions cont.
Wellness
• state of wellness is experienced
when the body maintains
homeostasis.
Illness
• state of illness occurs when 1 or more of the
body's control systems lose ability to maintain
homeostasis
Definitions cont.
Prevention of Illness organized into 3 levels:
1) Primary
•
•
Prevent initial occurrence of disease or injury by
maintaining homeostasis.
Ex of how to:
 Practicing good lifestyle habits
 avoiding exposure to bact & viruses
2) Secondary
•
Treat conditions that do occur as quickly as
possible to prevent further damage.
3) Tertiary
•
Rehabilitate to allow person to regain as much fx
as possible & prevent further disability.
Question
• Which of the following is an example of
objective data?
A. Headache
B. High blood pressure
C. Numbness in arm
B. High blood pressure
Body System:
Body system
= When 2 or more organs combine to
perform major body function
• Systems work together (Interrelated) to
maintain homeostasis or wellness
Body
Systems
Systems providing Movement & Protection are:
Skeletal, Muscular, & Integumentary Systems
– Provide support
– Allow movement
– Protect body
The Integumentary
System
Integumentary System
Largest organ in body
 15% of body wt
 surface area ~ 25 ft2 in adult
 consists of Skin & its Appendages,
which include:
Hair, nails,
sweat glands,
& oil glands
Integumentary System
• Protects from environmental hazards, such as:
 sunrays
 bacteria
 Heat, cold, pain, pressure
• Helps controls body temp via sweating &
vasoconstricting/dilating BV’s
• Prevents dehydration by acting as waterproof
membrane
• helps maint Homeostasis
Layers of the Skin
• Epidermis
• Dermis
• Subcutaneous tissue
Epidermis
• =‘s outer layer of , consisting:
 of 5 – 6 layers c no blood supply or nerves
 outermost layer composed of cells (squamous)
that have died from environ exposure & are shed
daily
 shed cells are replaced c cells produced in lower
layers thru out lifetime
 About 500 million
squamous cells are
lost every day
Fascinating Facts
• Humans shed ~ 600,000
particles of skin q hr, which
is ~ 1.5 lbs per yr.
• By age 70, ave person will
have lost 105 lbs of skin.
• Humans shed & re-grow
outer skin cells ~ q 27 days.
That totals ~ 1000 new
skins in a lifetime.
Epidermis & Skin Pigmentation
• Skin pigmentation determined by Melanocytes
that produce pigment Melanin.
• Melanocytes loc’d lower epidermis
• Melanin can be black, brown, or yellow,
depending upon racial origin
• amt of melanin (& other
skin pigments such as
carotene & hemoglobin) in
melanocytes determines
shades of human skin.
Epidermis & Skin Pigmentation
• Patches of melanin = Freckles or, if related to
damaged skin areas, "age spots.“
• Albino = person who has no skin pigmentation.
Dermis
• 2nd layer of skin
• contains invol. muscles (arrector pili muscles
cause "goose bumps"), BV’s, nerves, hair
follicles, sudoriferous (sweat) glands, &
sebaceous (oil) glands.
Subcutaneous Tissue
• innermost layer of skin
• contains fat & connective tissue (CT),
which fastens skin to underlying muscles
Skin Structures
Skin Appendages: Hair
• each hair encased in (sits in) a hair follicle
& ends in a root where new hair growth
occurs.
•composed of a
fibrous protein called
keratin, which is a
nonliving cell, so haircuts
are not painful
Skin Appendages: Nails
• Fingernails & Toenails also made of keratin
• growth of the nail occurs at the base of nail
under the half-moon shaped area
• fx of nails is to protect fingers & toes
Skin Appendages: Sudoriferous (Sweat) Glands
• during perspiration, water mixed c salt &
waste products are excr’d thru sweat
glands
• fx is to excrete excess water & assist in
cooling body by
evaporation of
water from skin
Skin Appendages: Sebaceous (Oil) Glands
• excrete oily substance (sebum) to lubricate
& protect skin
• Sebum is slightly acidic,
so it discourages growth of bacteria.
Fascinating Facts
• fingernail or toenail takes ~ 6 months to
grow from base to tip
• beards are fastest growing hairs on body.
If never trimmed, beard could grow
to 30 feet in length over ave lifetime
• 45 miles of nerves just in the
skin of a human
The Skin
Animation
Click Here to Play
The Skin Animation
Diseases & Disorders of Skin
Athlete's foot:
• infection of skin caused by a fungus
Fungus under
Microscope
Diseases & Disorders of Skin
Boils (furuncles):
• bacterial infection of hair follicles or
sebaceous glands.
Diseases & Disorders of Skin
Skin Cancer: 3 forms
1. Basal Cell
• most common & easiest to treat
2. Squamous Cell
• more serious
3. Melanoma
• most serious & can
be life-threatening
Diseases & Disorders of Skin
Cellulitis
• bacterial infection of dermis & subcut
layers of skin
Diseases & Disorders of Skin
Pressure Sores = Bed Sores = Decubitus
Ulcers:
• areas of skin breakdown that occur over
bony prominence due to excessive &
prolonged pressure that prevents
adequate circ to tissues.
Diseases & Disorders of Skin
Dermatitis:
• general name for inflammation of skin
• Contact dermatitis = allergic rx to a
substance that makes contact c skin
Diseases & Disorders of Skin
Eczema:
• is a generalized skin irritation usu’ly caused
by an irritant
• appears as reddened areas on surface skin
Diseases & Disorders of Skin
Psoriasis:
• chronic, noncontagious,
inherited skin dis, in which too many
epithelial cells are produced.
Diseases & Disorders of Skin
Warts:
• caused by viral infection of skin.
Integumentary System – Preventive Measures
• good hygiene & keep skin clean
• Do not break open pimples or other growths
on skin.
• Do not scratch insect bites or other irritations
• Avoid excessive exposure to sun
• Use sunscreen & wear a hat when in sun
• Have skin changes checked immediately.
• Protect skin from poisonous plants & insect
bites.
• Get adequate amounts of vit’s A & C & niacin
Integumentary System – Age Related Changes
• Decr’d: Elasticity of the skin, subcutaneous fat
(insulation), and hair (head, face)
• Incr’d: Dryness, wrinkles, skin pigmentation,
and susceptibility to irritation
Question
• Which of the following is the outer layer of
skin?
A. Dermis
B. Subcutaneous
C. Epidermis