Week 4 2
NSG 6006 WEEK 4: ADVANCED PATHOPHYSIOLOGY
Lecture Summaries
Cell Biology /Cellular response/Cell environment
Cell Biology/Adaptation
Cells become specialized through the process of differentiation or maturation. The eight
specialized cellular functions are movement, conductivity, metabolic absorption, secretion,
excretion, respiration, reproduction, and communication. The eukaryotic cell consists of three
general components: plasma membrane, cytoplasm, and intracellular organelles.
The nucleus is the largest membrane-bound organelle and is usually found in the cell's center.
Vaults are cytoplasmic organelles. They are carrying messengers of ribonucleic acid (mRNA)
from the nucleus to the ribosomal sites of protein synthesis. The plasma membrane encloses the
cell and, by controlling the movement of substances across it, exerts a powerful influence on
metabolic pathways.
Atrophy is a decrease in cellular size. Hypertrophy is an increase in the size of cells by increased
work demands or hormonal stimulation. Hyperplasia is an increase in the number of cells caused
by an increased rate of cellular division. Dysplasia, or atypical hyperplasia, is an abnormal change
in the size, shape, and organization of mature tissue cells. Metaplasia is the reversible replacement
of one mature cell type by another less mature cell type.
Cellular Environment
Body fluids are distributed among functional compartments and are classified as intracellular fluid
(ICF) or extracellular fluid (ECF). The sum of all fluids is the total body water (TBW), which
varies with age and the amount of body fat. Water moves between the plasma and interstitial fluid
by osmosis and hydrostatic pressure. Edema is a problem of fluid distribution that results in the
accumulation of fluid in the interstitial spaces. (Please refer to figure 3-2 in your textbook, which
shows the mechanisms of edema formation.)
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NSG 6006 Pre-Specialty Evaluation
©2017 South University
, Advanced Pathophysiology
Week 4 3
Immunologic/Infectious
Two types of human defense mechanisms exist: (1) innate resistance or immunity conferred by
natural barriers, and (2) the inflammatory response and the adaptive (acquired) immune system.
First, let’s look at the mechanisms related to the inflammatory response. Vascular response in
acute inflammation includes vasodilation, increased capillary permeability, and adherence of
white blood cells to inner vessel walls and their migration through the vessel walls. Three plasma
protein systems provide a biochemical barrier against invading pathogens in the circulation.
Types of cells involved in the inflammatory process, including mast cells, granulocytes
(neutrophils, eosinophils, and basophils), monocytes or macrophages, natural killer (NK) cells,
lymphocytes, and cellular fragments (platelets). The inflammatory response is initiated upon
tissue injury or pathogen-associated molecular patterns that are recognized by pattern recognition
receptors on cells of the innate immune system. Local manifestations of inflammation are the
result of vascular vasodilation and increased capillary permeability. The symptoms include
redness, heat, swelling, and pain.
Immunity
Cells of the innate system most often initiate the adaptive immune response. These cells process
and present portions of invading pathogens (e.g., antigens) to lymphocytes in peripheral lymphoid
tissue. Adaptive immunity can be either active or passive, depending on whether the immune
response components originated in the host or came from a donor.
Hypersensitivity Disorders
There is a wide range of pathologic alterations in the immune response and are covered
extensively in the textbook Pathophysiology: The Biologic Basis for Disease in Adults and
Children. There are four types of common disorders, I‒IV. These hypersensitivity disorders are an
"exaggeration" of the immune response, resulting in a variety of disorders. The two more
common include type I and type IV. Type I is the immediate hypersensitivity disorder and is
mediated by IgE, i.e., allergic rhinitis and asthma. Type IV is delayed hypersensitivity and is from
direct contact.
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NSG 6006 Pre-Specialty Evaluation
©2017 South University
, Advanced Pathophysiology
Week 4 4
Genetics/Genomics
To review the full spectrum of genetics/genomics visit the textbook chapters to learn more.
Genes
Genes are structures within the chromosomes of each cell in our body that contain
deoxyribonucleic acid (DNA).. Genetic abnormalities occur when one of the following holds true:
An existing error in coding is transcribed to the new DNA.
A transcription error occurs that results in an error in coding.
Mutation in the coding occurs after transcription.
Genotype vs. Phenotype
A genotype refers to a map of an individual's complete genome. The phenotype refers more to
the individual's response to his or her genetic makeup and is influenced by both the genotype and
the environment.
Dominance and Recessiveness
An allelomorph, or allele, is DNA coding that occurs in a specific location on a chromosome.
Alleles that exhibit an observable effect are known as dominant, and alleles that don't exhibit an
observable effect are said to be recessive. Both parents must contribute a recessive allele at the
same location on one of the twenty-two autosomal chromosomes before the recessive trait can
create an observable effect. If only one parent contributes the autosomal recessive allele and the
other contributes an autosomal dominant allele, then the autosomal dominant allele will produce
the observable effect.
Genetic abnormalities may also be coded on the sex chromosomes and are known as X-linked
chromosomes because they occur on the X chromosome. No disorders have been documented that
code on the Y chromosome. Male and female carriers of autosomal disorders are equally likely to
pass the disorder to their offspring.
Look at some common genetic disorders such as Turner and Klinefelter syndrome to review
clinical manifestations and treatment. Other disorders may occur to mutation in oncogenes such as
BRCA1 and BRCA2 mutations.
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NSG 6006 Pre-Specialty Evaluation
©2017 South University
, Advanced Pathophysiology
Week 4 5
Cardiovascular
Heart murmurs are caused by valve disorders. Extra heart sounds are caused due to disorders of
the heart chambers. Aortic stenosis is one of the most common systolic murmurs heard in patients
who are over fifty years old, and systolic murmur is that of mitral valve prolapse. Diastolic
murmurs are almost always pathologic such as Aortic regurgitation.
Remember that S1 signifies closing of the mitral and tricuspid valves and simultaneously opening
of the aortic and pulmonic valves. S2 signifies closing of the aortic and pulmonic valves and
opening of the mitral and tricuspid valves.
Extra heart sounds are different from heart murmurs. The two most common extra heart sounds are
S3 and S4. For the most part, extra heart sounds signify heart failure and come after S1 and S2, but
before the next S1. These typically result from distended and noncompliant chambers of the heart
such as the atrium and ventricles.
Hypertension is one of the most important causes of mortality. Hypertension is not just a
cardiovascular disease as it affects other vital organs like the brain, eyes, and the kidneys.
Hypertension can be either primary or secondary. The cause of primary hypertension is not known.
It is important to be familiar with the common risk factors that contribute to high blood pressure.
Hyperlipidemia occurs in adults as well as children and adolescents. Lipids, generally known as
fats in the blood stream, tend to increase with age. This result in a condition called hyperlipidemia,
which is a risk factor for accelerated vascular disease. Cholesterol and triglycerides are the main
culprits causing hyperlipidemia.
The development of atherosclerosis (CAD) begins at a very early age and does not develop
overnight. In fact, endothelial injury begins with insult from a variety of sources. Such as
Smoking, high blood pressure, blood sugars or cholesterol levels.
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NSG 6006 Pre-Specialty Evaluation
©2017 South University