Chapters 4 & 10 of the Integrated A&P for Allied Health

1. Anatomyand
Physiology
S U Z A N N E S . F R U C H T
For Allied Health
Integrated

2. Integrated Anatomy and Physiology: Chapter 4
Integumentary System
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LEARNING OBJECTIVES
Following completion of this chapter, the student will be able to:
1. list the functions of the skin.
2. identify the layers of the skin.
3. identify the layers of the epidermis.
4. locate and describe the function of
sebaceous glands and sweat glands.
5. describe the functions of the sensory
receptors of the skin.
6. identify the structures of hair and nails.
7. discuss common integumentary
pathological conditions, diagnostic
procedures, and treatment procedures.
8. define chapter Key Terms.
OVERVIEW
The integumentary system consists of the skin (also called the integument or cutaneous membrane)
and its accessory organs: sweat glands, sebaceous glands, hair, sensory receptors, and nails. The
skin is not just the outer covering of the body; it is the largest organ of the body and performs many
vital functions, including:
• It is a two-way barrier protecting against invasion by pathogens, ultraviolet light damage, loss
of body fluids, and physical trauma.
• It assists in regulating body temperature. Evaporation of sweat cools the body. Dilating
superficial blood vessels releases excess heat and constricting the same blood vessels conserves
heat. Adipose tissue of the hypodermis is thermal insulation.
• The many sensory receptors in the skin provide vital sensory information to the brain.
• It excretes waste products such as small amounts of salt, water, and organic waste.
• It synthesizes vitamin D, which is important for calcium metabolism.
• The hypodermis stores energy in its adipose tissue.
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LAYERS OF THE SKIN AND THE HYPODERMIS
The skin is divided into two layers: the superficial epidermis and the deeper dermis. Deep to the
dermis is a layer called the hypodermis (also called the subcutaneous layer). The hypodermis is a
continuous layer of adipose tissue that separates the skin from deeper tissues. It is not technically
considered part of the skin, but is usually studied along with the skin and assists in some of its
functions.
Each layer is composed of a different type of tissue and therefore has its own characteristic
appearance.
Epidermis
• superficial layer
• composed of
stratified squamous
keratinized epithelium
• avascular
• consists of 5 layers in
thick skin and 4 layers
in thin skin
Dermis
• deep layer
• composed of connective tissue
• highly vascular
• consists of 2 layers
• houses glands, hair, and
sensory receptors
Hypodermis
• also called subcutaneous layer
• deep to dermis
• primarily composed of
adipose tissue
• also called subcutaneous layer
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Figure 4.1 The two layers of the skin and the hypodermis.
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Layers of the Epidermis
The epidermis consists of four or five (depending on body location) distinct layers. The primary cell
type is keratinocytes, whose main function is to produce keratin, a hard protein. New keratinocytes
are continually produced in the deepest layer, the stratum basale (or basal layer), and begin to
migrate toward the surface layer, the stratum corneum. The epidermis as a whole layer is avascular,
meaning it has no blood vessels. For this reason, the stratum basale is the only living layer of the
epidermis because it can receive needed nutrients from the adjacent dermis. As keratinocytes move
upward through each layer they die and become keratinized. During this process the internal cell
organelles are replaced with keratin. The oldest cells on the surface are continually shed and make up
the majority of household dust. Because there are many layers of flat, dry, dead, and keratinized cells,
the epidermis is an efficient two-way barrier, keeping out pathogens like bacteria and preventing loss
of water and vital body substances.
Stratum corneum
• most superficial layer
• 25–30 rows
• dead, flat keratinocytes
• continually slough off
Keratinocyte
• found in all epidermal
layers
• most abundant skin cell
• produces keratin
Melanocyte
• found in stratum basale
• cell extension grow into
stratum spinosum
• produce melanin
• melanin is a dark
pigment, which gives
skin and hair its color
Dermis
Stratum lucidum
• found only in thick skin of
palm and sole
• 3–5 layers of flattened, clear,
dead keratinocytes
Stratum granulosum
• 3–5 layers of flattened
keratinocytes
• cells are dying, flattening,
and filling with keratin
Stratum spinosum
• 8–10 layers of many-sided
keratinocytes
• keratinocytes are beginning
to die and shrink
• have characteristic“spiny”
appearance
Stratum basale
• deepest layer
• contacts dermis
• single layer of actively
dividing cells
• also called stratum
germinativum
Merkel cell
• found in stratum basale
• associated with Merkel’s
disc, a touch receptor
Langerhan’s cell
• found in stratum
spinosum
• migrate from bone
marrow
• protect against bacteria
Sensory neuron
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Figure 4.2 The five layers of the epidermis.
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Structure of the Dermis
The dermis is the thickest layer of the skin. It consists of a superficial papillary layer and deep
reticular layer. Because it is composed of connective tissue rich in collagen and elastic fibers, this
layer gives the skin strength and flexibility. It has a rich blood supply and is the location of most of
the skin’s accessory organs: hair, glands, and sensory receptors.
Vein
Artery
Papillary layer
• contacts stratum basale
• composed of areolar
connective tissue
Free nerve ending
• a sensory receptor
Pacinian
corpuscle
• a sensory
receptor
Apocrine sweat
gland
Sebaceous gland
Merocrine (eccrine)
sweat gland
Hair
Arrector pili muscle
Capillary
network
Reticular layer
• bulk of dermis
• composed of dense
irregular connective
tissue
• contacts hypodermis
Meissner’s corpuscle
• a sensory receptor
Dermal papilla
• extensions of
papillary layer
into epidermis
Hair follicle
plexus
• a sensory
receptor
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Figure 4.3 Structure of the dermis.
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ACCESSORY ORGANS
Glands
There are two different types of skin glands: sudoriferous glands, which produce sweat, and
sebaceous glands that secrete an oil called sebum. Although these glands are formed from the
epidermis infolding downward into the dermis (called invagination), they are considered part of
the dermis. There are two sub-types of sudoriferous glands: merocrine (eccrine) sweat glands and
apocrine sweat glands. The secretions of each type of gland assist the skin in performing its various
functions. Sweat, or perspiration, from merocrine sweat glands is a watery secretion containing a
small amount of salts and waste products. Sweat assists in cooling the body by evaporation. Sweat
from apocrine sweat glands is thicker and promotes bacterial growth. This is responsible for body
odor. Both types of sweat glands increase their secretions in response to heat and stress. Sebum
lubricates the skin, making it more flexible and better able to resist bacterial growth.
Sweat pore
Apocrine sweat gland
• a type of sudoriferous
gland
• found mainly in axillae
and genital region
• secretes thick substance
responsible for body odor
• secretes directly into
a hair follicle
Merocrine sweat gland
• a type of sudoriferous gland
• most common type of sweat gland
• found in most areas of the skin
• secretes watery sweat
• sweat duct empties onto skin surface
• sweat evaporation cools skin
• sweat contains small amount
of waste products
• also called eccrine glands
Duct emptying
into hair follicle
Sweat duct
Sebaceous gland
• secretes sebum
• secretes directly into a
hair follicle
• sebum is an oil that
lubricates skin to keep it
flexible and prevent
cracking
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Figure 4.4 Glands of the dermis.
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Sensory Receptors
Exteroceptors are sensory receptors that respond to stimuli from the external environment. The
sensory receptors located in the dermis (or very deepest levels of the epidermis) belong to this group
because they monitor the external environment that is in contact with the skin. This includes what
is touching your body (both lightly and with deep pressure), what temperature your body is being
exposed to, if your skin is being stretched (as occurs during movement), and if there is something
harming your skin and causing pain. On the other hand, interoceptors monitor internal body
conditions. Sensory receptors can also be classified by their structure. All the sensory receptors in
the skin are dendrites of the sensory neurons that carry the information to the brain. In free nerve
endings, the dendrites are bare. In encapsulated nerve endings, the dendrites are surrounded by a
connective tissue capsule.
Epidermis
Dermis
Subcutaneous
layer
Pacinian corpuscle
• encapsulated
• found deep in dermis
• detects deep touch
and pressure
• also called lamellated
corpuscle
Ruffini’s corpuscle
• encapsulated
• found in dermis
• detects stretching
Thermoreceptors
• free nerve endings
• found in dermis
• cold receptors detect
between 10–40 o
C
• warm receptors detect
between 32–49 o
C
Hair root complex
• free nerve endings
• found wrapped around
hair follicle
• detects hair movement
Meissner’s corpuscle
• encapsulated
• found in papillary region
of dermis
• detects light touch and
pressure
• also called tactile
corpuscles
Merkel discs
• free nerve endings
• found at junction of epidermis and dermis
• detect sustained touch and pressure
Nociceptors
• free nerve endings
• found in dermis and
basal layer of epidermis
• detect pain as a result
of tissue damage
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Figure 4.5 Sensory receptors of the skin.
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Hair
Hair is present on most of the surface area of the body. It is absent on the soles of the feet, the palms
of the hands, the sides of the fingers and toes, the lips, and parts of the external genitals. It grows
much like the epidermis, meaning new cells are produced in the base of the hair and as the cells
move upward, they die and become keratinized. Also as in the epidermis, melanin gives hair its color.
Papilla
• connective tissue cells
• extend into hair bulb
• contains blood vessels to bring
nutrients to dividing cells
Hair bulb
• enlarged base of hair root
• contains the matrix, group of cells
dividing to form new hair cells
Hair root
• portion of hair below skin surface
• root and shaft consist of dead,
keratinized cells
Hair follicle
• invagination of epidermal cells
• forms sheath around hair root
Hair shaft
• portion of hair above skin surface
• shaft and root consist of dead, keratinized cells
Arrector pili muscle
• bundle of smooth muscle fibers
• extends from hair follicle into dermis
• contracts to make hair stand up
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Figure 4.6 Structure of a hair.
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Nails
Like the epidermis and hair, nails are composed of dead, keratinized cells. In this case the cells form a
hard, flat plate that covers and protects the ends of fingers and toes.
Free edge of nail
• unattached end of nail
• extends outward from fingers and toes
Nail body
• flat plate of keratinized cells
• bulk of nail
Nail bed
• area of skin under nail body
• nail body is firmly attached
Distal phalanx
Epidermis
Dermis
Nail matrix
• actively dividing cells
• produces new nail cells
Nail root
• newly produced nail cells
• embedded under fold of skin
Cuticle
• thin layer of skin
• seals off nail root
Lunula
• half moon-shaped area
• at base of nail
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Figure 4.7 Structures of the nail.
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CLINICAL CONNECTION
Pathological Conditions
condition
(pronunciation)
med term review definition
Burns
burn
Injury to skin caused by heat (thermal),
electricity, ultraviolet light, or chemicals;
serious depends on depth of damage and
total area of body affected
burn, 1st degree
Damage is only to the epidermis; no
blisters form; example is a mild sunburn
burn, 2nd degree
Damage to the epidermis and dermis;
blisters form; also called partial-thickness
burn
burn, 3rd degree
Destroys epidermis and dermis, damages
hypodermis; also called full-thickness
burn
Skin Cancer
basal cell carcinoma (BCC)
(kar-sih-NOH-mah)
bas/o = the base
-al = pertaining to
carcin/o = cancer
-oma = tumor
Skin cancer originating in the basal layer
of the epidermis; most common and least
harmful skin cancer
CD-10-CM code C44.91
basal cell carcinoma of skin, unspecified
malignant melanoma
(MM)
(mel-ah-NO-mah)
melan/o = black
-oma = tumor
Skin cancer originating in a melanocyte;
dangerous and aggressive skin cancer;
prone to spreading (metastasizing) to
other locations
ICD-10-CM code C43.9
malignant melanoma of skin, unspecified
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condition
(pronunciation)
med term review definition
squamous cell carcinoma
(SCC)
(SKWAY-mus / cell / kar-sih-
NOH-mah)
carcin/o = cancer
-oma = tumor
Skin cancer originating in squamous
skin cells; appear as sores that will not
heal; can spread (metastasize) to other
locations
Take a Closer Look At … Skin Cancer
Cancer, no matter where it begins, starts in a single cell. Over a long
period of time, the cell's DNA becomes damaged and the cell begins to
grow and divide uncontrollably, forming a mass of abnormal cells, the
cancerous tumor. In addition, these cells are abnormal in their shape
and function, and they no longer carry out the intended function of the
cell. As the tumor grows larger, it invades the neighboring tissue and
the cells around the edges break loose and spread to other parts of the
body, a process called matastisizing. The most important risk factor for
developing skin cancer is exposure to ultraviolet light.
Normal cells Cancer cells
Skin Infections
Take a Closer Look At … Skin Infections
Since one of the primary jobs of the skin is to protect us from invading pathogens, it is not surprising
that it is very common to see the results of these pathogens trying to invade the body. The most
basic definition of pathogen [path/o = disease; -gen = that which produces] is anything that causes
disease. The list of potential pathogens is long and diverse. Typically, persons think of bacteria and
viruses as pathogens. But the list also includes fungi (like yeast), protozoans (like amoebas), animal
parasites (like lice and worms), and even toxins (like poisons). When looking specifically at skin
infections, the most common types are bacterial, viral, fungal, and parasitic.
Bacterial Infections
Bacteria are single-cell organisms. They are microscopic in size and
vary widely in shape. Bacteria are everywhere in our environment.
The vast majority are friendly to us or, at least, neutral toward us.
However, a small number attempt to invade the body through
our skin. The most common families of pathogenic bacteria are
staphylococcus, sterptococcus, and pseudomonas. Bacterial
infections are typically treated with antibiotic medications that
either kill the bacteria or prevent it from reproducing. A big health
concern is the increasing number of bacteria that have developed a
resistance to antibiotics that have been overused.
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condition
(pronunciation)
med term review definition
impetigo
(im-pe-TYE-go)
Highly contagious bacterial skin infection;
characterized by pustules
ICD-10-CM code L01.00
impetigo, unspecified
abscess
(AB-sess)
An enclosed pocket containing pus;
usually caused by bacterial infection
cellulitis
(sell-yoo-LIGH-tis)
-itis = inflammation
Bacterial infection of the connective
tissue of the skin
Viral Infections
Viruses are officially referred to as subcellular particles. They are
not alive because they do not have all the cellular organelles to
survive and reproduce independently. So, in truth, viruses are a
type of parasite because they take over living cells and trick them
into producing new virus particles. Since viruses are not living
organisms, antibiotics are not useful in treating viral infections.
Antiviral medications typically interfere with a virus’ability to invade
a living cell or its ability to reproduce inside a living cell.
varicella
(vair-ih-SELL-ah)
Highly contagious viral infection;
characterized by papules that change to
vesicles and then pustules; commonly
called chickenpox
ICD-10-CM code B01.9
varicella, without complication
genital herpes
genit/o = external
reproductive
organs
-al = pertaining to
Viral infection by herpes simplex virus,
type 2 (HSV-2); characterized by vesicles
around the genitals or rectum
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condition
(pronunciation)
med term review definition
oral herpes
or/o = mouth
-al = pertaining to
Viral infection by herpes simplex virus,
type 1 (HSV-1); characterized by vesicles
around the lips; commonly called fever
blisters or cold sores
rubella
(roo-BELL-ha)
from the Latin word
ruber, meaning red
Viral skin infection; commonly called
German measles
shingles
Infection by herpes zoster virus;
characterized by painful vesicles along
nerve path
verruca
(veh-ROO-kah)
from the Latin word
verruca, meaning
wart
A skin growth caused by a virus;
commonly called a wart
Fungal Infections
When you think of a fungus, you often think of bread mold and
mushrooms. But there are some fungi that cause skin infections.
They often occur in warm, moist regions of the skin. They typically
cause skin cracking, weeping (oozing) sores, and an intense itch.
Treatment requires medication that specifically targets fungi.
tinea corporis
(TIN-ee-ah / COR-por-is)
from Latin word
corporis, meaning
body
Fungal infection of the trunk; commonly
called ringworm
ICD-10-CM code B35.4
tinea corporis
tinea capitis
(TIN-ee-ah / KAP-ih-tis)
from Latin word,
capitis, meaning
head
Fungal infection of scalp; commonly
called ringworm
tinea pedis
(TIN-ee-ah / PEE-dis)
from Latin word pedis,
meaning foot
Fungal infection of the foot; commonly
called athlete's foot
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condition
(pronunciation)
med term review definition
Parasitic Infections
(or infestations)
Parasitic skin infections are typically caused by very tiny, sometimes
microscopic, animals living on the skin surface or burrowed in
the epidermis layer. These organisms feed on skin cells and debris
that collects on the skin. Each different type of parasite requires a
medication specifically designed to kill it.
pediculosis
(peh-dik-you-LOW-sis)
pedicul/o = lice
-osis = abnormal
condition
Skin infection caused by lice; they
typically live in the hairy regions of the
body (head and pubic region); lice lay
eggs, called nits, attached to hair shaft
ICD-10-CM code B85.2
pediculosis, unspecified
scabies
(SKA-bees)
from Latin term
scabo, meaning to
scratch
Skin condition caused by infestation by
the itch mite
Additional Skin Infections
dermatitis
(der-nah-TYE-tis)
dermat/o = skin
-itis = inflammation
Condition characterized by inflammation
of the skin (redness, swelling, and itching)
eczema
(ek-ZEE-mah)
Type of dermatitis; characterized by
erythema, pruritus, and vesicles
purulent
(PYOU-roo-lent)
A condition that produces pus; for
example an abscess
Skin Lesions (abnormality, wound, or injury)
abrasion
(ah-BRAY-shun)
from Latin word
abrado, meaning to
scrape off
Traumatic injury that scrapes away the
superficial layers of skin
cicatrix
(sick-AY-tricks)
from Latin word
cicatrix, meaning a
scar
A scar
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condition
(pronunciation)
med term review definition
contusion
(con-TOO-shun)
from Latin word,
contusio, meaning a
bruising
Traumatic injury without break in skin;
characterized by pain, swelling, and
bruising
cyst
(SIST)
from Greek word
kystis, meaning
bladder
An enclosed sac that contains fluid or
semi-solid material, other than pus
ecchymosis
(eck-ih-MOH-sis)
-osis = abnormal
condition
Black-and-blue bruising caused by
bleeding into the skin from trauma and
ruptured blood vessels
erythema
(air-ih-THEE-mah)
erythr/o = red
Redness of the skin caused by dilated
capillaries
fissure
(FISH-er)
A narrow slit or crack in the skin surface
keloid
(KEY-loyd)
A hypertrophic or abnormally large scar
laceration
(lass-eh-RAY-shun)
from Latin word,
laceratus, meaning
to cut
A jagged cut or torn skin wound
macule
(MACK-yool)
-ule = small
Small, flat, discolored spot; examples are
freckles and flat moles
papule
(PAP-yool)
-ule = small Small, solid, raised skin lesion
pustule
(PUS-tyool)
-ule = small
Small, raised skin lesion specifically
containing pus; example is a whitehead
pimple
ulcer
(UL-sir)
from Latin word ulcus,
meaning a sore
Area where skin has eroded away leaving
an open sore
vesicle
(VESS-ih-kul)
vesic/o = bladder Small skin blister containing fluid
wheal
(WHEEL)
Small, swollen area that itches; may
appear as a symptom of an allergic
reaction; example is itchy, swollen new
mosquito bite
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condition
(pronunciation)
med term review definition
Additional Skin Conditions
acne vulgaris
(AK-nee / vul-GA-ris)
Chronic inflammatory condition, most
common in adolescents; characterized by
inflammation, papules, and pustules
decubitus ulcer (decub)
(dee-KYOU-bih-tus / UL-ser)
from Latin word
decunbo, meaning
to lie down
Caused by prolonged pressure on skin
that cuts off the circulation to the area
resulting in necrosis and ulcers; persons
unable to change their position (lying or
sitting) are at risk
Take a Closer Look At … Decubitus Ulcers
Decubitus ulcers, or pressure ulcers, typically develop over
bony prominences, such as the heels, hips, sacrum, elbows,
scapulae, or back of skull. This is an ischemic [isch/o = to hold
back; -hemic = pertaining to blood] condition because the skin
and its blood vessels become pinched by the weight of the
body pressing a bony prominence against a hard surface. This
shuts off the blood supply to the surrounding skin. It is easier
to prevent these ulcers than to treat them. For this reason, it is
critical that at-risk patients be repositioned frequently, at least
every two hours. At-risk patients include the critically ill, frail,
comatose, and paralyzed.
Etiology of Pressure Sores
Normal
Bone
Soft tissue
Blood vessels
Skin layers
Bone
Soft tissue
Blood vessels
Skin layers
Pressure of bone
against hard surface
Pinching off of
blood vessels
Friction of
skin against
the surface
Hard surface
(bed)
Soft tissue
Epidermis
Dermis
Subcutaneous
fat
Bone
1 2
3 4
Stages
1 – area of redness that
does not blanch
white
2 – shallow ulcer
present
3 – deep ulcer extends
through dermis
4 – bone or muscle
exposed by ulcer
ICD-10-CM codes
Pressure ulcer, unspecified site,
unspecified stage – L89.90
stage 1 – L89.91
stage 2 – L89.92
stage 3 – L89.93
stage 4 – L89.94
unstageable – L89.95
gangrene
(GANG-green)
from Greek word
gangraina,
meaning an eating
sore
Necrosis usually caused by loss of
circulation to an area followed by
bacterial infection
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condition
(pronunciation)
med term review definition
necrosis
(neh-CROW-sis)
necr/o = death
-osis = abnormal
condition
Death to an area of tissue; some causes
include traumatic injury, infection, and
loss of blood supply
pruritus
(proo-RIGH-tus)
from the latin word
pruritus, meaning
itching
Intense itching; often associated with
infections and allergic reactions
psoriasis
(soh-RYE-ah-sis)
from the Greek word
psora, meaning the
itch
Skin condition characterized by episodes
of red papules covered by silvery scales
urticaria
(er-tih-KAY-ree-ah)
from the Latin word
urtica, meaning
stinging nettle
Hives; skin allergic reaction characterized
with pruritus and wheals
Nail and Hair Conditions
alopecia
(al-oh-PEE-she-ah)
from Greek word
alopekia, meaning
a disease like fox
mange
Absence or permanent loss of hair,
especially on the head; commonly called
baldness
carbuncle
(KAR-bung-kul)
A cluster of furuncles
furuncle
(FU-rung-kul)
Bacterial infection of a hair follicle or
sebaceous gland; characterized by
swelling, pain, and pus; commonly called
a boil
onychomycosis
(on-ih-koh-my-KOH-sis)
onych/o = nail
myc/o = fungus
-osis = abnormal
condition
Fungal infection of the nails
onycophagia
(on-ih-koh-FAY-jee-ah)
onych/o = nail
-phagia = to eat
Nail biting
trichomycosis
(trik-oh-my-KOH-sis)
trich/o = hair
myc/o = fungus
-osis = abnormal
condition
Fungal infection of the hair
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Diagnostic Procedures
procedure
(pronunciation)
med term review definition
Clinical Laboratory Tests
culture and sensitivity
(CS)
Laboratory test that identifies bacterial
infections by growing bacteria from
collected samples; if bacteria is found, then
various antibiotics are tested to determine
which is most effective
Surgical Procedures
biopsy (bx, BX)
(BYE-op-see)
bi/o = life
-opsy = to view
Diagnostic test in which a small piece of
tissue is removed (by needle, syringe, knife,
punch, or brush) and examined under a
microscope
Treatment Procedures
procedure
(pronunciation)
med term review definition
Pharmacology
antibiotic
anti- = against
bi/o = life
-tic = pertaining to
Medication that kills bacteria-causing skin
infections; may be oral (a pill) or topical (a
cream)
antifungal
(an-tye-FUNG-all)
anti- = against
-al = pertaining to
Medication that kills fungi-causing skin
infections; usually topical
antiparasitic
(an-tye-pair-ah-SIH-tic)
anti- = against
-tic = pertaining to
Medication that kills parasites infesting the
skin; usually topical
corticosteroids
(kor-tih-koh-STAIR-oid)
cortic/o = outer
portion
Medication that reduces inflammation; may
be oral (a pill) or topical (a cream)
Surgical Procedures
cauterization
(kaw-ter-eye-ZAY-shun)
cauter/o = burning
Destruction of skin lesion using electricity,
chemicals, heat, or freezing
chemabrasion
(keem-ah-BRAY-shun)
chem/o = chemical
Use of chemicals to remove superficial
layers of skin; also called chemical peel
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procedure
(pronunciation)
med term review definition
cryosurgery
(cry-oh-SER-jer-ee)
cry/o = cold
Use of extreme cold to freeze and destroy
abnormal tissue
curettage
(koo-REH-tahz)
Scraping off of superficial skin lesions or
damaged tissue
debridement
(duh-BREED-mint)
Removal of damaged tissue and debris
from a wound
dermabrasion
(der-mah-BRAY-zhun)
derm/o = skin
Use of wire brush to remove superficial
layers of skin; removes acne and varicella
scars
dermatoplasty
(DER-mah-toe-plas-tee)
dermat/o = skin
-plasty = surgical
repair
Replacement of damaged skin by healthy
skin from a donor site; also called skin graft
incision and drainage
(ID)
cis/o = to cut
Cutting open a lesion and draining its
contents; for example opening and
draining the pus from an abscess
laser surgery
Using a laser to remove skin lesions or
birthmarks
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CHAPTER SUMMARY
System Review
• The integumentary system consists of the skin and its accessory organs: sweat glands,
sebaceous glands, hair, sensory receptors, and nails.
• The functions of the skin include: acting as a two-way barrier, temperature regulation, providing
sensory information, excreting waste products, synthesizing vitamin D, and storing energy.
Key Terms
The following list contains the key terms introduced and defined in this chapter. Review this list and
look up any terms you are unable to define.
epidermis
keratinocytes
keratin
stratum basale
stratum spinosum
stratum granulosum
stratum lucidum
stratum corneum
melanocytes
melanin
dermis
merocrine sweat glands
apocrine sweat glands
sweat
sebum
nociceptors
Merkel discs
Meissner’s corpuscle
thermoreceptors
hair root complex
Ruffini’s corpuscle
Pacinian corpuscle
hypodermis
hair shaft
hair root
arrector pili muscle
hair follicle
hair bulb
papilla
nail body
nail matrix
nail root
lunula
cuticle
nail bed
Chapter Highlights
• The skin has two layers: the superficial epidermis and deeper dermis (see Figure 4.1).
• The hypodermis is a continuous layer of adipose tissue between the skin and underlying tissue.
It is not a layer of the skin but is studied with the skin. This is an important energy storage site
(see Figure 4.1).
• The epidermis consists of 4 or 5 layers, depending on the location. These layers are the: stratum
basale, stratum spinosum, stratum granulosum, stratum lucidum, and stratum corneum
(see Figure 4.2).
• The epidermis is composed of stratified squamous epithelium and the primary cell is the
keratinocyte (see Figure 4.2).
• Keratinocytes migrate from the stratum basale to the skin surface. During this process they die
and their insides are replaced with keratin (see Figure 4.2).
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• Melanocytes are cells containing melanin, the dark pigment molecule that gives skin and hair
its color (see Figure 4.2).
• The dermis is the thickest layer of the skin and houses the accessory organs: glands, hair, and
sensory receptors (see Figure 4.3).
• The dermis has two layers. The superficial papillary layer contacts the stratum basale of the
epidermis and is composed of areolar connective tissue. The deeper reticular layer contacts the
hypodermis and is composed of dense irregular connective tissue, rich in collagen and elastic
fibers (see Figure 4.3).
• Merocrine sweat glands produce a watery substance called sweat. Evaporation of sweat cools
the skin (see Figure 4.4).
• Apocrine sweat glands produce a thick sweat that promotes bacterial growth and causes body
odor (see Figure 4.4).
• Sebaceous glands secrete sebum, an oil that lubricates and protects the skin (see Figure 4.4).
• Sensory receptors provide the brain with information regarding the external environment
contacting the skin. They may be free nerve endings or encapsulated nerve endings (see
Figure 4.5).
• Nociceptors detect pain, Merkel discs detect touch and pressure, Meissner’s corpuscles detect
light touch, thermoreceptors detect cold and heat, hair root complexes detect hair movement,
Ruffini’s corpuscles detect stretching, and Pacinian corpuscles detect deep pressure (see
Figure 4.5).
• Like the epidermis, hair is composed of dead, keratinized cells. New hair cells are produced in the
hair matrix and grow toward the skin surface within the hair follicle. The hair root is below the
skin surface and the hair shaft is above the skin surface (see Figure 4.6).
• Nails are composed of dead, keratinized cells that form a flat plate, called the nail body, covering
the ends of toes and fingers. New nail cells are formed at the nail matrix. The nail root is the
portion of the nail embedded under a fold of skin. The nail body is firmly attached to underlying
tissue called the nail bed (see Figure 4.7).
• Pathological conditions of the skin include cancerous tumors; burns; bacterial, viral, and fungal
infections; parasitic infestations; allergic reactions; inflammatory conditions; traumatic injuries;
and various skin lesions.
• Diagnostic procedures obtain tissue samples for microscopic examination or to determine
bacterial infections.
• Treatment procedures include medications to treat a variety of infections and to reduce
inflammation and surgical procedures to remove damaged or dead tissue, drain fluids from
infected areas, and skin grafts.
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24. Integrated Anatomy and Physiology: Chapter 10
Cardiovasular System: Heart
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LEARNING OBJECTIVES
Following completion of this chapter, the student will be able to:
1. recognize the heart’s location in the thoracic
cavity.
2. identify the great vessels, heart chambers,
and heart valves.
3. describe the layers of the heart wall.
4. locate the arteries and veins of the coronary
circulation and the area of the heart that
each serves.
5. relate the order in which the stimulus to
contract is conducted through the heart.
6. recognize the parts of an ECG wave.
7. discuss common cardiovascular
pathological conditions, diagnostic
procedures, and treatment procedures.
8. define chapter Key Terms.
OVERVIEW
The cardiovascular system is designed to transport substances through the entire body, delivering
needed materials and removing waste products. It consists of a pump, the heart, that contracts to
push blood through a series of tubes, the blood vessels.
The heart wall is composed of cardiac muscle fibers that contract to squeeze blood passing through
its four chambers. This creates the pressure necessary to push blood through all of the blood vessels
of the body. Arteries carry blood away from the heart, veins carry blood toward the heart, and
capillaries (organized into extensive networks called capillary beds) are the site of substance
exchange between the blood and the cells and tissues of the body.
The heart will be covered in Chapter 10 and blood and blood vessels will be addressed in Chapter 11.
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THE HEART IN THE THORACIC CAVITY
The heart is located in the mediastinum of the thoracic cavity. It is approximately the size of your fist
and lies between the lungs and superior to the diaphragm. The heart is protected by the vertebral
column posteriorly and the sternum anteriorly. The heart is surrounded by the pericardium, which
forms a protective sac around it.
Right lung
Left lung
Apex of heart
• inferior pointed tip
• points to left side
Diaphragm
Parietal pericardium
• inner lining of
pericardial sac
• thin serous membrane
• forms pericardial sac with
fibrous pericardium
• protects heart
• anchors heart to body
wall and diaphragm
Visceral pericardium
• thin serous membrane
• attached to surface
of heart and part of
the heart wall
• also called epicardium
Base of heart
• broad superior region
• area where great vessels attach to heart
Pericardial cavity
• space between two
pericardial membranes
• contains serous fluid
• reduces friction between
heart and surrounding
tissue when heart beats
Mediastinum
• central region of thoracic
cavity
• between lungs
• contains heart, great vessels,
trachea, esophagus, and
thymus gland
Fibrous pericardium
• outer layer of pericardial
sac
• composed of thick
connective tissue
• forms pericardial sac with
visceral pericardium
• resembles a bag
• anchors heart to body
wall and diaphragm
Figure 10.1 Position of the heart within the thoracic cavity and the layers of the pericardium.
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EXTERNAL ANATOMY
Heart Chambers
The heart consists of four chambers that are visible both externally and internally. They are the right
atrium, right ventricle, left atrium, and left ventricle. The atria are the smaller superior chambers.
The much larger inferior chambers are the ventricles. Oxygenated blood is supplied to the heart
muscle by coronary arteries, which are branches of the aorta.
Right auricle
• pouch-like extension
of right atrium
• expands to increase
volume of blood
atrium may hold
Left auricle
• pouch-like extension of
left atrium
• expands to increase
volume of blood atrium
may hold
Left atrium
• upper chamber on left
side of heart
• receives blood from
pulmonary veins
• sends blood to left
ventricle
Left ventricle
• lower chamber on left side of heart
• receives blood from left atrium
• sends blood to aorta
Right ventricle
• lower chamber on right side of heart
• receives blood from right atrium
• sends blood to pulmonary trunk
Right atrium
• upper chamber on right
side of heart
• receives blood from
inferior and superior
vena cavae and coronary
sinus
• sends blood to right
ventricle
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Figure 10.2 The four heart chambers, anterior external view.
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Great Vessels
All the great vessels (with the exception of the pulmonary arteries) are attached to the base of
the heart. These vessels include the inferior vena cava, superior vena cava, pulmonary trunk,
pulmonary arteries, pulmonary veins, and aorta. Each of the great vessels is associated with one of
the chambers of the heart. They either deliver blood to an atrium or receive blood pumped out of a
ventricle. The exception is the pulmonary arteries; they receive blood from the pulmonary trunk.
Aortic arch
Ascending aorta
Descending aorta
Left pulmonary artery
• carries deoxygenated blood
• receives from pulmonary
trunk
• delivers to capillary bed in
left lung
Pulmonary trunk
• carries deoxygenated blood
• receives from right ventricle
• delivers to pulmonary arteries
Left pulmonary veins
• carry oxygenated
blood from left lung
• delivers to left atrium
Inferior vena cava
• carries deoxygenated blood
• drains lower regions of body
• delivers to right atrium
Superior vena cava
• carries deoxygenated blood
• drains upper regions of body
• delivers to right atrium
Right pulmonary veins
• carry oxygenated blood
from right lung
• delivers to left atrium
Right pulmonary artery
• carries deoxygenated blood
• receives from pulmonary trunk
• delivers to capillary bed in
right lung
Aorta
• carries oxygenated blood
• receives from left ventricle
• delivers to systemic arteries
• largest artery in the body
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Figure 10.3 Great vessels that deliver blood to or receive blood from the heart, anterior view.
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Coronary Circulation
The heart muscle does not receive its oxygen and nutrients from the blood passing through its
chambers, but relies on the coronary circulation. The right and left coronary arteries are actually
branches of the aorta that arise just above the aortic valve. Each curves down to supply oxygen and
nutrients to the heart muscle. Deoxygenated blood is collected by the coronary veins and returned
directly to the right atrium.
Aorta
Left coronary artery
• arises from left side of aorta
• passes posterior to pulmonary trunk
• divides into two major branches: anterior
interventricular artery and circumflex artery
Circumflex artery
• branch of left coronary artery
• occupies posterior coronary sulcus
• supplies left atrium and posterior left ventricleMarginal arteries
• branches of right coronary artery
• run along inferior border of heart
• supply right ventricle
Anterior interventricular artery
• branch of left coronary artery
• occupies anterior interventricular sulcus
• supplies left ventricle and interventricular
septum
Posterior interventricular artery
• branch of right coronary artery
• occupies posterior interventricular sulcus
• supplies distal areas of both ventricles
Right coronary artery
• arises from right side of aorta
• occupies coronary sulcus
• small branches supply right atrium
• divides into: posterior interventricular
artery and marginal arteries
Anastomosis between right coronary
artery and circumflex artery
Anastomosis between anterior interventricular
artery and posterior interventricular artery
Small cardiac vein
• runs along heart’s inferior right margin
• drains right atrium and ventricle
• empties into coronary sinus
Middle cardiac vein
• occupies posterior interventricular sulcus
• drains distal areas of both ventricles
• empties into coronary sinus
Coronary sinus
• an enlarged vein
• occupies posterior part of coronary sulcus
• drains blood from cardiac veins
• empties into right atrium
Great cardiac vein
• occupies anterior interventricular sulcus
• drains left ventricle and interventricular septum
• empties into coronary sinus
Anterior cardiac veins
• several horizontal veins on
anterior surface of right ventricle
• drains distal areas of both
ventricles
• empties directly into right atrium
(a)
(b)
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Figure 10.4 The arteries and veins that serve the heart, anterior view. a) Arteries. b) Veins.
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INTERNAL ANATOMY
Heart Chambers
It is easy to see the internal anatomical differences between the atria and ventricles that reflect the
function of each chamber. Atria have a thin muscular wall. Their primary function is to collect blood
returning to the heart and then contract to deliver it to the ventricles. The ventricles are much larger
volumed chambers and have a very thick wall. They are the primary pumping chambers. Because
the left ventricle must push blood a greater distance, it has the thickest, most muscular wall. Atria
communicate with ventricles, but the right and left halves of the heart are completely separated from
each other by a muscular wall, the septum. For this reason, it is able to function as a double pump.
Each half pumps blood into a different circuit. The right side of the heart receives deoxygenated
blood from the body and pumps it to the lungs for oxygenation—the pulmonary circulation. The
left side of the heart receives oxygenated blood from the lungs and pumps it to the body—the
systemic circulation.
Fossa ovalis
• visible remains of
foramen ovale in fetus
Right atrium
• receives deoxygenated
blood from superior and
inferior vena cavae
• empties into right ventricle
Left atrium
• receives oxygenated
blood from
pulmonary veins
• empties into left
ventricle
Interventricular septum
• muscular wall
• separates left and right ventricles
Left ventricle
• thicker muscular wall
• receives oxygenated
blood from left atrium
• pumps blood into aorta
Coronary sinus opening
• point at which coronary sinus
empties into right atrium
Right ventricle
• thinner muscular wall
• receives deoxygenated blood from right atrium
• pumps blood into pulmonary trunk
Trabeculae carneae
• ridges of cardiac muscle
• visible on inner surface of ventricles
Frontal
plane
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Figure 10.5 The four heart chambers and heart wall, anterior interior view.
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Heart Valves
The heart has four valves composed of strong fibrous tissue flaps called cusps, which close to prevent
regurgitation (backflow) of blood. This ensures that blood flows only in a forward direction through
the heart. One pair of valves, the atrioventricular valves (tricuspid valve on the right and mitral
valve [or bicuspid valve] on the left), are found between the atria and ventricles. They prevent blood
in the ventricles from flowing back into the atria when the ventricles contract. The second pair of
valves, the semilunar valves (pulmonary valve on the right side and aortic valve on the left), are
found between the ventricles and the great arteries. They prevent blood that has just been ejected
into the great arteries from flowing back into the ventricles when the ventricles relax. The two
audible heart sounds,“lub”and“dub”(or“dup”), occur as these valves close. Lub is caused by the
closing of the atrioventricular valves and dub is caused by the closing of the semilunar valves.
Frontal plane
Pulmonary valve
• semilunar valve
• between right ventricle
and pulmonary trunk
• prevents backflow into
right ventricle
Right atrium
Left atrium
Aortic valve
• semilunar valve
• between left
ventricle and aorta
• prevents backflow
into left ventricle
Mitral valve
• AV valve
• between left atrium
and ventricle
• prevents backflow
into left atrium
• also called bicuspid
valve
Chordae tendineae
• strands of tendinous tissue
• one end attached to edge of valve cusp
• other end attached to papillary muscle
• work with papillary muscle
Papillary muscle
• bundles of cardiac muscle
• attached to ends of chordae tendineae
• contract to tense chordae tendineae
• prevents valve cusps from moving into atria
Left ventricle
Tricuspid valve
• AV valve
• between right atrium
and ventricle
• prevents backflow
into right atrium
Right ventricle
Figure 10.6 The four valves of the heart, anterior interior view.
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Heart Wall
The wall of the heart is composed of three layers: the endocardium, myocardium, and epicardium.
Endocardium
Epicardium
Heart wall
Pericardial cavity
• contains serous fluid
Visceral pericardium
• the epicardium
Endocardium
• inner lining
• very thin and delicate
• simple squamous epithelium
Trabeculae
carneae
Myocardium
• middle layer
• cardiac muscle tissue
• contracts to pump blood
Parietal pericardium
• fibrous pericardial sac
Coronary
blood vessels
Pericardial
sac
Myocardium
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Figure 10.7 Structure of the heart wall.
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THE CARDIAC C YCLE
The Conduction System
In order to pump blood, the chambers of the heart alternate between a relaxation phase, called
diastole, and a contraction phase, called systole. One complete round of diastole and systole is
called the cardiac cycle (it is also one heartbeat). When a chamber is in diastole, blood is able to flow
into the chamber because it is relaxed. During systole, the chamber contracts, developing the force
needed to squeeze, or eject, blood from the chambers. The heart valves open and close to ensure
that blood only flows forward through the heart and not backward (called regurgitation). In order
to work effectively as a pump, the heart muscle must contract the chambers in a specific pattern. The
heart’s effectiveness is reduced if the ventricles contract before the atria finish delivering blood to
them. To accomplish this task, the heart has a network of interconnected, specialized cardiac muscle
cells called the conduction system that is able to stimulate a heartbeat. As the wave of stimulation
spreads through the conduction system, the chambers of the heart are stimulated to contract in
the proper sequence. It is important to note that while the heart is divided into left and right halves
for blood flow, the conduction system moves from the top to the bottom; meaning that both atria
contract together, then both ventricles contract together. The heart is unique in that it does not
require the nervous system to stimulate contraction, it is responsible for stimulating itself to contract.
The nervous system does play a role in adjusting the rate at which the heart contracts.
Interventricular septum
Left bundle branch
• carries stimulus to apex
of left ventricle
• stimulates Purkinje fibers
Purkinje fibers
• network in each ventricular wall
• conductile cells that carry stimulus
to ventricular cardiac muscle cells
Atrioventicular bundle
(AV bundle)
• located in interventricular septum
• receives stimulus from AV node
• carries stimulus to bundle
branches
• also called bundle of His
Sinoatrial node (SA node)
• called pacemaker of heart
• located near point superior
vena cava enters right atrium
• initates stimulus that results
in heart contraction
• stimulates internodal
pathway
Right bundle branch
• carries stimulus to apex of
right ventricle
• stimulates Purkinje fibers
Atrioventricular node
(AV node)
• located at junction of
atria and ventricles
• receives stimulus from
internodal pathway
• stimulates AV bundle
Internodal pathway
• receives stimulus
from SA node
• carries stimulus
throughout atria
• stimulates atrial
contraction and AV
node
1
2
3
4
5
6
5
Aorta
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Figure 10.8 Conduction system of the heart, anterior interior view with pulmonary trunk removed
in order to observe atrioventricular bundle.
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Because large regions of the heart muscle are stimulated and contract simultaneously, their electrical
activity can be detected and recorded by a machine called an electrocardiograph. The tracing of the
electrical current is called an electrocardiogram (ECG) and shows the changes in electrical voltage
over time. It is interesting to note that electrocardiogram may also be abbreviated as EKG. This relates
back to the German spelling of the word. To this day, ECG and EKG are used interchangeably. Figure
10.9 illustrates the parts of one complete ECG wave. Many heart abnormalities can be identified by
measuring the height and width of each wave and the size of the gaps between the waves.
Millivolts
Milliseconds
0
–0.5
0.5
1.0
0
200 400 600
T wave
• medium upward deflection
• ventricular diastole follows T wave
QRS complex
• series of three deflections
• Q – small downward deflection
• R – very tall upward deflection
• S – small to medium downward deflection
• complex represents spreading of
stimulation through the ventricles
• ventricular systole follows QRS complex
• atrial diastole also occurs during this time
but is not seen in the ECG wave
P wave
• small, upward deflection
• stimulation is spreading through the atria
• atrial systole follows P wave
T
S
R
Q
P
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Figure 10.9 Parts of an ECG wave.
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Cardiac Output
Cardiac output (CO) is the volume of blood pumped out of the left ventricle per minute. This is the
amount of blood circulating throughout the body. Cardiac output is determined by multiplying
stroke volume (SV), the volume of blood leaving the left ventricle with each beat, times the heart
rate (HR), the number of beats per minute. The equation for this is: CO = SV x HR.
The needs of the body change from minute to minute depending on activity level. For example,
during times of exertion, such as while exercising, the skeletal muscles need an increased blood flow
in order to obtain the oxygen and nutrients they need to work harder. Therefore, the heart needs to
be able to adjust cardiac output. This can be accomplished in two ways, either by increasing heart
rate or by increasing the force of contraction of the heart muscle (which increases stroke volume). In
this way, the heart is able to supply the proper amount of blood to each organ.
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CLINICAL CONNECTION
Pathological Conditions
condition
(pronunciation)
med term review definition
Cardiac Arrhythmias
arrhythmia
(ah-RITH-mee-ah)
a- = without
-ia = condition
A change from the normal heart rhythm;
examples include fibrillation, bradycardia,
and tachycardia; also called dysrhythmia
bradycardia
(BRAD-ee-kar-dee-ah)
brady- = slow
cardi/o = heart
-ia = condition
Type of arrhythmia with abnormally slow
heart rate; usually below 60 beats per
minute
ICD-10-CM code R00.1
Bradycardia, unspecified
fibrillation
(fih-brih-LAY-shun)
Type of arrhythmia with rapid, random,
quivering of the heart muscle; fails to
produce the coordinated contraction
necessary to pump blood; may be life
threatening
ICD-10-CM code I49.01
Ventricular fibrillation
flutter
Type of arrhythmia with very rapid (up to
300 beats/minute) but coordinated heart
contractions
ICD-10-CM code I48.3
Typical atrial flutter
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condition
(pronunciation)
med term review definition
heart block
Type of arrhythmia from disruption of the
movement of stimulus wave through the
conduction system; may be caused by scar
tissue or heart tissue damage
palpitations
(pal-pih-TAY-shuns)
from the Latin word
palpito, meaning to
throb
A pounding or racing heartbeat; often felt
as a fluttering sensation
premature atrial
contraction (PAC)
(A-tree-al)
atri/o = atrium
-al = pertaining to
Type of arrhythmia with contraction of the
atria too early in the cardiac cycle
premature ventricular
contraction (PVC)
(ven-TRIK-yu-lar)
ventricul/o = ventricle
-ar = pertaining to
Type of arrhythmia with contraction of the
ventricles too early in the cardiac cycle
tachycardia
(tack-ee-KAR-dee-ah)
tachy- = fast
cardi/o = heart
-ia = condition
Type of arrhythmia with abnormally fast
heart rate; usually applies to rates greater
than 100 beats per minute
ICD-10-CM code R00.0
Tachycardia, unspecified
Take a Closer Look At … Cardiac Arrhythmias
Arrhythmia is a general term that refers to a change in the rhythm of the heartbeat caused by a
problem with the conduction system. The heart beats either too fast, too slow, or irregularly. An
occasional irregular heartbeat is normal and can be affected by everyday things, such as caffeine,
nicotine, alcohol, stress, and physical activity. Arrhythmias may also be caused by medications,
a hyperactive thyroid gland, and, most commonly, heart disease. Arrhythmias range from
completely harmless to life threatening. The most dangerous arrhythmias reduce the heart's
ability to pump blood effectively. Symptoms of these arrhythmias include shortness of breath,
feeling light-headed, fatigue, dizziness, and fainting.
Many arrhythmias can be identified by electrocardiography (ECG or EKG). This procedure
measures and records the wave of stimulation as it moves through the heart muscle via the
conduction system. Depending on the nature of the arrhythmia, many are treated by medications
to restore normal rhythm. A surgically implanted pacemaker may be necessary to treat
bradycardia and an implantable cardioverter defibrillator may be necessary to shock the heart
back to a normal rhythm if it goes into fibrillation.
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condition
(pronunciation)
med term review definition
Heart Conditions
angina pectoris
(an-JI-nah / PEK-to-ris)
pect/o = chest
Episodes of severe pain in the chest
caused by insufficient oxygen supplied to
the heart muscle
cardiac arrest
(KAR-dee-ak)
cardi/o = heart
-ac = pertaining to
Stoppage of all heart function
cardiac tamponade
(KAR-dee-ak /
tam-poh-naid)
cardi/o = heart
-ac = pertaining to
Occurs when fluid accumulates in the
pericardial sac; this puts pressure on the
heart and prevents the ventricles from
fully expanding and reduces cardiac
output; may be caused by trauma to the
chest cavity
congestive heart
failure (CHF)
(kon-JES-tiv)
Inability of the heart to effectively pump
blood through the circulatory system;
symptoms include shortness of breath
and swelling in the feet and ankles
coronary artery
disease (CAD)
(koh-roh-NAIR-ee)
coron/o = heart
-ary = pertaining to
A hardening and narrowing
(atherosclerosis) of the coronary arteries
supplying blood to the heart muscle;
may result in angina pectoris, myocardial
infarction, or sudden death
Take a Closer Look At … Atherosclerosis
Atherosclerosis can affect any of the larger blood vessels of the body. It
is the most common cause of cardiovascular diseases, such as coronary
artery disease, angina pectoris, and myocardial infarction. It is also the
most common cause of cerebrovascular accidents.
Atherosclerosis develops over a long period of time as cholesterol
and cellular debris accumulates in the lining of a blood vessel forming
a plaque that bulges out into the open lumen of the artery. As the
plaque grows larger, it reduces the amount of blood that can flow past
it. The tissue downstream from the plaque begin to suffer, resulting in
CAD and angina pectoris. A thrombus may form at the plaque, which
completely shuts off blood flow, leading to a sudden myocardial
infarction.
ICD-10-CM code
I70.90
Atherosclerosis,
unspecified
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condition
(pronunciation)
med term review definition
cardiomegaly
(kar-dee-oh-MEG-ah-
lee)
cardi/o = heart
-megaly = enlarged
An abnormal enlargement of the heart
cardiomyopathy
(KAR-dee-oh-my-OP-
ah-thee)
cardi/o = heart
my/o = muscle
-pathy = disease
Disease of the heart muscle itself; often
from an unknown cause; major reason for
heart transplants
myocardial infarction
(MI)
(my-oh-KAR-dee-al /
in-FARK-shun)
my/o = muscle
cardi/o = heart
-al = pertaining to
The blockage (occlusion) of blood flow in
a coronary artery; results in the death of
the heart muscle served by that artery;
may result in permanent damage to the
heart muscle or sudden death; commonly
called a heart attack
Infections
endocarditis
(endo-kar-DIE-tis)
endo- = inside
cardi/o = heart
-itis = inflammation
Inflammation of the lining of the heart
chambers; often caused by a bacterial
infection
pericarditis
(per-ih-kar-DYE-tis)
peri- = around
cardi/o = heart
-itis = inflammation
Inflammation of either layer of the
pericardial sac
Congenital Defects
congenital defects
(kon-JEN-ih-tal)
-al = pertaining to Heart defects present from birth
patent ductus
arteriosus (PDA)
(PAY-tent / DUCK-tus /
ar-te-re-OH-sus)
arteri/o = artery
Type of congenital defect with failure of
a fetal blood vessel between pulmonary
artery and aorta to close at birth
atrial septal defect
(A-tree-al / SEP-tal)
atri/o = atrium
-al = pertaining to
sept/o = wall
Type of congenital defect with failure of
the foramen ovale to close over at birth,
leaving a hole in the interatrial septum
ICD-10-CM code Q21.1
Atrial septal defect
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condition
(pronunciation)
med term review definition
ventricular septal
defect
(ven-TRIK-yu-lar)
ventricul/o = ventricle
-ar = pertaining to
sept/o = wall
Type of congenital defect with the
presence of a hole in the interventricular
septum at birth
ICD-10-CM code Q21.0
Ventricular septal defect
Take a Closer Look At … Congenital Septal Defects
Ventricular septal defects is the most common congenital heart defect. When the heart first
forms in a fetus, the right and left ventricles are open to each other. As the fetus grows, the
interventricular septum forms. If the septum does not completely form, a hole (septal defect)
remains.
Atrial septal defects are much less common. In a fetus, an opening between the left and right
atrium is normal. This allows blood to go from the right atrium directly into the left atrium,
bypassing the pulmonary circulation. This occurs because the fetus' blood is being oxygenated by
the placenta, not the lungs. This hole normally closes at birth when the baby takes its first breath.
Small septal defects often do not have any symptoms. In the case of larger holes, symptoms
include shortness of breath, heart palpitations, and frequent respiratory infections. The presence
of a septal defect is diagnosed using echocardiography to visualize the internal heart structures.
Small septal defects often heal on their own. But if symptoms are severe enough, then heart
surgery to place a patch across the defect is performed.
Heart Valve Conditions
murmur
(mer-mer)
from the Latin word
murmur, meaning a
low noise
A change from the normal heart sounds;
often indicates a problem with a heart
valve
valvular prolapse
(VAL-vue-lar /
PROH-laps)
valvul/o = valve
-ar = pertaining to
Cusps of a heart valve are too loose; results
in inability of the valve to close tightly
valvular stenosis
(VAL-vue-lar /
steh-NOH-sis)
valvul/o = valve
-ar = pertaining to
Cusps of a heart valve become too stiff;
results in inability of the valve to either
open or close fully
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Diagnostic Procedures
procedure
(pronunciation)
med term review definition
Clinical Laboratory Tests
cardiac enzymes
(KAR-dee-ak)
cardi/o = heart
-ac = pertaining to
A blood test to identify substances released into
the bloodstream from damaged heart muscle cells
Diagnostic Imaging
cardiac catheterization
(KAR-dee-ak / kath-eh-
ter-eye-ZAY-shun)
cardi/o = heart
-ac = pertaining to
A thin, flexible tube (a catheter) is threaded
through blood vessels to the heart; dye is inserted
in order to view the flow of blood through the
coronary arteries (angiography)
cardiac magnetic
resonance imaging
(MRI)
(KAR-dee-ak)
cardi/o = heart
-ac = pertaining to
Use of radio waves in a strong magnetic field to
produce extremely clear images of the size and
thickness of the heart chambers
echocardiography
(EK-oh-kar-dee-OG-rah-
fee)
ech/o = sound
cardi/o = heart
-graphy = process
of recording
An ultrasound image of the heart; used to visualize
movement of the heart valves and strength of
heart muscle contraction
Heart Function Tests
electrocardiography
(ECG, EKG)
(ee-leck-troh-kar-dee-
OG-rah-fee)
electr/o =
electricity
cardi/o = heart
-graphy = process
of recording
Process of recording the electrical activity of the
heart; produces an electrocardiogram (record of
the heart's electrical activity)
Holter monitor
A portable heart monitor worn for at least 24 hours;
continuously monitors the heart's activity
stress test
An evaluation of heart function produced while
the patient is engaged in stressful activity such as
walking on a treadmill or riding a bicycle
thallium stress test
(THAL-ee-um)
A specialized type of stress test that uses
radioactive thallium injected into the bloodstream
to show how well blood flows into the heart
muscle, both at rest and during activity such as
walking on a treadmill
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Treatment Procedures
procedure
(pronunciation)
med term review definition
Medical Procedures
cardiopulmonary
resuscitation (CPR)
(kar-dee-oh-PULL-moh-
nair-ee)
cardi/o = heart
pulmon/o = lung
-ary = pertaining to
Emergency life-support procedure consisting of
chest compressions to pump blood and mouth-
to-mouth breathing to move air into the lungs
defibrillation
(dee-fib-rih-LAY-shun)
de- = without
Applying electrical shock to the external chest in
order to restore normal heart rhythm; also called
cardioversion
Pharmacology
antiarrhythmic
(an-tye-a-RHYTH-mik)
anti- = against
a- = without
-ic = pertaining to
Medication to prevent or reduce severity of
arrhythmias
cardiotonic
(card-ee-oh-TAHN-ic)
cardi/o = heart
-tonic = pertaining
to tone
Medication that improves the force of a heart
contraction; treatment for congestive heart
failure
thrombolytic
(throm-boh-LIT-ik)
thromb/o = clot
-lytic = pertaining
to destruction
Medication that dissolves an existing blood clot;
used to treat myocardial infarction
Surgical Procedures
coronary artery
bypass graft (CABG)
(koh-roh-NAIR-ee)
coron/o = heart
-ary = pertaining to
Open-heart surgery in which a vein from another
part of the body is grafted onto the heart to
bypass a blocked artery; also called bypass
surgery
heart transplant
The replacement of a diseased heart by a donor
heart
implantable
cardioverter
defibrillator
(KAR-dee-oh-ver-ter /
dee-fib-rih-LAY-ter)
cardi/o = heart
de- = without
An electrical device implanted in the chest
with electrodes to the heart; able to treat both
bradycardia and fibrillation
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procedure
(pronunciation)
med term review definition
pacemaker
An electrical device implanted in the chest with
electrodes to the heart; primarily used to treat
bradycardia
percutaneous
transluminal
angioplasty (PCTA)
(per-kyou-TAY-nee-ous
/trans-LOO-mih-nal/
AN-jee-oh-plas-tee)
per- = through
cutane/o = skin
-ous = pertaining to
trans- = across
-al = pertaining to
angi/o = vessel
-plasty = surgical
repair
During a cardiac catheterization procedure,
a small balloon at the tip of the catheter is
inflated in order to open up a coronary artery by
flattening the blockage; following the balloon
procedure, a wire mesh tube, a stent, may be
left in place to keep the artery open; also called a
balloon angioplasty
valvuloplasty
(VAL-view-loh-plas-tee)
valvul/o = valve
-plasty = surgical
repair
The surgical repair or replacement of a heart
valve; also called valvoplasty
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CHAPTER SUMMARY
System Review
• The cardiovascular system is designed to transport substances through the entire body,
delivering needed materials and removing waste products.
• The organs or the cardiovascular system are the heart, a pump that contracts to push blood
through a series of tubes, the blood vessels.
• The heart is a hollow organ. Its wall is composed of cardiac muscle fibers that contract to
squeeze blood passing through its four hollow chambers. This creates the pressure necessary to
push blood through all of the blood vessels of the body.
• Arteries carry blood away from the heart, veins carry blood toward the heart, and capillaries
(organized into extensive networks called capillary beds) are the site of substance exchange
between the blood and the cells and tissues of the body.
Key Terms
The following list contains the key terms introduced and defined in this chapter. Review this list and
look up any terms you are unable to define.
pericardium
pericardial cavity
apex
base
right auricle
right atrium
left auricle
left atrium
right ventricle
left ventricle
inferior vena cava
superior vena cava
pulmonary trunk
right pulmonary artery
left pulmonary artery
right pulmonary veins
left pulmonary veins
aorta
right coronary artery
posterior interventricular artery
marginal arteries
left coronary artery
anterior interventricular artery
circumflex artery
anterior cardiac veins
middle cardiac vein
small cardiac vein
great cardiac vein
coronary sinus
fossa ovalis
coronary sinus opening
trabeculae carneae
interventricular septum
atrioventricular valves
tricuspid valve
mitral valve
bicuspid valve
chordae tendineae
papillary muscle
semilunar valves
pulmonary valve
aortic valve
lub
dub
endocardium
myocardium
epicardium
pericardial sac
diastole
systole
cardiac cycle
sinoatrial node
internodal pathway
atrioventricular node
atrioventricular bundle
left bundle branch
right bundle branch
Purkinje fibers
electrocardiograph
electrocardiogram
P wave
QRS complex
T wave
cardiac output
stroke volume
heart rate
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Chapter Highlights
• The heart is located in the mediastinum, the middle region of the thoracic cavity and sits on the
diaphragm. The pointed, distal tip of the heart is the apex. The broad, superior region, where the
great vessels attach, is the base (see Figure 10.1).
• The heart is surrounded by a double-layered, protective sac, the pericardium. The outer layer is
the pericardial sac and consists of the fibrous pericardium and the parietal pericardium. The
inner layer is the visceral pericardium (also called the epicardium). The space between the two
layers is the pericardial cavity (see Figure 10.1).
• The heart consists of four hollow chambers, two superior and two inferior. The superior atria
receive blood returning to the heart and deliver it to the ventricles. The inferior ventricles
contract forcefully to pump blood into arteries (see Figures 10.2 and 10.5).
• The great vessels of the heart include the superior and inferior vena cava, the pulmonary
trunk, the right and left pulmonary arteries, the right and left pulmonary veins, and the
aorta (see Figure 10.3).
• The heart muscle does not receive its oxygen and nutrients from the blood passing through
its chambers, but relies on the coronary circulation. The right and left coronary arteries are
branches of the aorta. Each curves down and branches to supply oxygen and nutrients to the
heart muscle. Deoxygenated blood is collected by the coronary veins and returned directly to
the right atrium (see Figure 10.4).
• There are four valves in the heart. They close to prevent regurgitation of blood and ensure that
blood flows only in a forward direction. Atrioventricular valves, tricuspid valve on the right
and mitral valve on the left, are found between the atria and ventricles. Semilunar valves,
pulmonary valve on the right and aortic valve on the left, are found between the ventricles and
the great arteries. The audible heart sounds, lub and dub, are produced by the closing of these
valves (see Figure 10.6).
• The heart is divided into left and right halves by a solid wall, the septum and functions as a
double pump. Each half pumps blood into a different circuit. The right side of the heart receives
deoxygenated blood from the body and pumps it to the lungs for oxygenation—the pulmonary
circuit. The left side of the heart receives oxygenated blood from the lungs and pumps it to the
body—the systemic circuit.
• The wall of the heart is composed of three layers. The endocardium is the inner lining. The thick
myocardium contracts to pump blood. The epicardium (also the visceral pericardium) is the
outer layer of the heart wall (see Figure 10.7).
• The cardiac cycle consists of one round of diastole (relaxation and filling phase) and systole
(contraction and pumping phase). In order to work effectively as a pump, the heart muscle must
contract the chambers in a specific pattern. This is accomplished by the heart’s conduction
system. As the stimulus passes from one structure in the conduction system to the next, the
chambers contract in the proper sequence. The conduction system consists of the sinoatrial
node (initiates the stimulus), the internodal pathway, the atrioventricular node, the
atrioventricular bundle, the left and right bundle branches, and finally the Purkinje fibers
(see Figure 10.8).
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• As the heart muscle is stimulated and contracts, the electrical activity can be detected and
recorded by an electrocardiograph. A typical wave consists of three sections: the P wave, the
QRS complex, and the T wave (see Figure 10.9).
• Cardiac output is the volume of blood pumped out of the left ventricle per minute. It is
determined by multiplying stroke volume, the volume of blood leaving the left ventricle with
each beat, times the heart rate, the number of beats per minute.
• Pathological conditions of the heart may be caused by blockage of the coronary arteries,
resulting in insufficient oxygen to the heart muscle, abnormal heart rhythms, congenital defects
in heart structures, disease of the heart muscle tissue itself, inflammatory conditions, and
damage to the valves.
• Diagnostic procedures evaluate the blood flow to the heart muscle, produce images of the
heart, measure the electrical activity of the heart, and evaluate how the heart responds to stress.
• Treatment procedures include surgical procedures to improve circulation to the heart muscle,
implanting electrical devices to regulate the heartbeat, and repair damaged valves.
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