NR 283 PATHO FINAL EXAM 3 STUDY GUIDE / NR283 PATHO FINAL EXAM 3 STUDY GUIDE: 100% CORRECT,CHAMBERLAIN COLLEGE OF NURSING
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NR 283 (NR283)
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CHAMBERLAIN COLLEGE OF NURSING
NR 283 PATHO FINAL EXAM 3 STUDY GUIDE / NR283 PATHO FINAL EXAM 3 STUDY GUIDE: 100% CORRECT,CHAMBERLAIN COLLEGE OF NURSINGNR 283 PATHO FINAL EXAM 3 STUDY GUIDE / NR283 PATHO FINAL EXAM 3 STUDY GUIDE: 100% CORRECT,CHAMBERLAIN COLLEGE OF NURSINGNR 283 PATHO FINAL EXAM 3 STUDY GUIDE / NR283 PATHO FINAL...
CHAPTER 1
Common cellular adaptations
Atrophy refers to a decrease in the size of cells, resulting in a reduced tissue
mass. Common causes include reduced use of the tissue, insufficient nutrition,
decreased neurologic or hormonal stimulation, and aging. An example is the
shrinkage of skeletal muscle that occurs when a limb is immobilized in a cast for
several weeks.
• Hypertrophy refers to an increase in the size of individual cells, resulting in an
enlarged tissue mass. This increase may be caused by additional work by the
tissue, as demonstrated by an enlarged heart muscle resulting from increased
demands. A common example of hypertrophy is the effect of consistent exercise
on skeletal muscle, leading to an enlarged muscle mass. Excessive hormonal
stimulation may also stimulate cell growth.
• Hyperplasia is defined as an increased number of cells resulting in an enlarged
tissue mass. In some cases, hypertrophy and hyperplasia occur simultaneously, as
in the uterine enlargement that occurs during pregnancy. Hyperplasia may be a
compensatory mechanism to meet increased demands, or it may be pathologic
when there is a hormonal imbalance. In certain instances there may be an increased
risk of cancer when hyperplasia occurs.
• Metaplasia occurs when one mature cell type is replaced by a different mature
cell type. This change may result from a deficit of vitamin A. Sometimes,
metaplasia may be an adaptive mechanism that provides a more resistant tissue; for
instance, when stratified squamous epithelium replaces ciliated columnar
epithelium in the respiratory tracts of cigarette smokers. Although the new cells
present a stronger barrier, they result in decreased defenses for the lungs because
cilia are no longer present as a defense mechanism for the simpler squamous cells
in the mucosa.
• Dysplasia is the term applied to tissue in which the cells vary in size and shape,
large nuclei are frequently present, and the rate of mitosis is increased. This
situation may result from chronic irritation infection, or it may be a precancerous
,change. Detection of dysplasia is the basis of routine screening tests for atypical
cells such as the Pap smear (Papanicolaou test on cervical cells).
• Anaplasia refers to cells that are undifferentiated with variable nuclear and cell
structures and numerous mitotic figures. Anaplasia is characteristic of cancer and
is the basis for grading the aggressiveness of a tumor.
• Neoplasia means “new growth,” and a neoplasm is commonly called a tumor.
Tumors are of two types, benign and malignant. Malignant neoplasms are referred
to as cancer. Benign tumors do not necessarily become malignant. Benign tumors
are usually considered less serious because they do not spread and are not life
threatening unless they are found in certain locations, such as the brain, where they
can cause pressure problems. The characteristics of each tumor depend on the
specific type of cell from which the tumor arises, resulting in a unique appearance
and growth pattern. Neoplasms are discussed further in
Cell damage (Ischemia)
Apoptosis refers to programmed cell death, a normal occurrence in the body,
which may increase when cell development is abnormal, cell numbers are
excessive, or cells are injured or aged. Cells self-destruct, appearing to digest
themselves enzymatically, and then disintegrate into fragments.
There are many ways of injuring cells in the body, including:
•Ischemia, a decreased supply of oxygenated blood to a tissue or organ, due to
circulatory obstruction
•Physical agents, excessive heat or cold, or radiation exposure
•Mechanical damage such as pressure or tearing of tissue
•Chemical toxins
•Microorganisms such as bacteria, viruses, and parasites
•Abnormal metabolites accumulating in cells
•Nutritional deficits
•Imbalance of fluids or electrolytes
,The most common cause of injury is ischemia or reduced blood supply to the
tissue, which results in insufficient oxygen and reduced cellular metabolism.
Decreased oxygen in the tissue may occur locally because of a blocked artery or
systemically because of respiratory impairment. Cells with a high demand for
oxygen, such as those of the brain, heart, and kidney, are quickly affected
by hypoxia (reduced oxygen in the tissue). A severe oxygen deficit interferes with
energy (ATP) production in the cell, leading to loss of the sodium pump at
the cell membrane as well as loss of other cell functions. An increase in sodium
ions inside the cell leads to swelling of the cell and eventually to rupture of
the cell membrane. At the same time, in the absence of
oxygen, anaerobic metabolism occurs in the cell, leading to a decrease in pH from
build of lactic acid and further metabolic impairment. A deficit of other essential
nutrients such as vitamins may also damage cells because normal metabolic
processes cannot take place.
CHAPTER 2
Fluid deficit- Dehydration
Dehydration refers to insufficient body fluid resulting from inadequate intake or
excessive loss of fluids or a combination of the two. Losses are more common and
affect the extracellular compartment first. Water can shift within the extracellular
compartments. For example, if fluid is lost from the digestive tract because of
vomiting, water shifts from the vascular compartment into the digestive tract to
replace the lost secretions. If the deficit continues, eventually fluid is lost from the
cells, impairing cell function.
Fluid loss is often measured by a change in body weight; knowing the usual body
weight of a person is very helpful in assessment of the extent of loss. As a general
guide to extracellular fluid loss, a mild deficit is defined as a decrease of 2% in
body weight, a moderate deficit as a 5% weight loss, and severe dehydration is a
decrease of 8%. This figure should be adjusted for the individual's age, body size,
and condition.
Dehydration is a more serious problem for infants and elderly people, who lack
significant fluid reserves as well as the ability to conserve fluid quickly. Infants
also experience not only greater insensible water losses through their
proportionately larger body surface area but also an increased need for water
owing to their higher metabolic rate. The vascular compartment is rapidly depleted
in an infant (hypovolemia), affecting the heart, brain, and kidneys. This is
, indicated by decreased urine output (number of wet diapers), increased lethargy,
and dry mucosal membranes.
Water loss is often accompanied by a loss of electrolytes and sometimes of
proteins, depending on the specific cause of the loss. For example, sweating results
in a loss of water and sodium chloride. Electrolyte losses can influence water
balance significantly because electrolyte changes lead to osmotic pressure change
between compartments. To restore balance, electrolytes as well as fluid must be
replaced. Isotonic dehydration refers to a proportionate loss of fluid and
electrolytes, hypotonic dehydration to a loss of more electrolytes than water, and
hypertonic dehydration to a loss of more fluid than electrolytes. The latter two
types of dehydration cause signs of electrolyte imbalance and influence the
movement of water between the intracellular and extracellular compartments
(see Electrolyte Imbalances).
Causes of Dehydration
Common causes of dehydration include:
1.Vomiting and diarrhea, both of which result in loss of numerous electrolytes and
nutrients such as glucose, as well as water; drainage or suction of any portion of
the digestive system can also result in deficits
2.Excessive sweating with loss of sodium and water
3.Diabetic ketoacidosis with loss of fluid, electrolytes, and glucose in the urine
4.Insufficient water intake in an elderly or unconscious person
5.Use of a concentrated formula in an attempt to provide more nutrition to an
infant
Effects of Dehydration
Initially, dehydration involves a decrease in interstitial and intravascular fluids.
These losses may produce direct effects such as:
•Dry mucous membranes in the mouth (see Table 2-3)
Decreased skin turgor or elasticity (Fig. 2-4)
•Lower blood pressure, weak pulse, and a feeling of fatigue
•Increased hematocrit, indicating a higher proportion of red blood cells compared
with water in the blood
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