WGU D236 pathophysiology Exam
-Study Guide-With 100% verified
answers-2022-2023

WGU D236 pathophysiology Exam -Study
Guide-With 100% verified answers-2022-
2023
Patho OA Study Guide
1. What is Starling's Law of Capillary forces? How does this
explain why a nutritionally deficient child would have edema?
Starling’s Law describes how fluids move across the capillary membrane. There
are two major opposing forces that act to balance each other, hydrostatic pressure
(pushing water out of the capillaries) and osmotic pressure (including oncontic pressure,
which pushes fluid into the capillaries). Both electrolytes and proteins (oncontic
pressure) in the blood affect osmotic pressure, high electrolyte and protein
concentrations in the blood would cause water to leave the cells and interstitial space
and enter the blood stream to dilute the high concentrations. On, the other hand, low
electrolyte and protein concentrations (as seen in a nutritionally deficient child) would
cause water to leave the capillaries and enter the cells and interstitial fluid which can
lead to edema.
2. How does the RAAS (Renin-Angiotensin-Aldosterone System)
result in increased blood volume and increased blood
pressure?
A drop in blood pressure is sensed by the kidneys by low perfusion, which in turn
begins to secrete renin. Renin then triggers the liver to produce angiotensinogen, which
is converted to Angiotensin I in the lungs and then angiotensin II by the enzyme
Angiotensin-converting enzyme (ACE). Angiotensin II stimulates peripheral arterial
vasoconstriction which raises BP. Angiotensin II is also stimulating the adrenal gland to
release aldosterone, which acts to increase sodium and water reabsorption increasing
blood volume, while also increased potassium secretion in urine.
3. How can hyperkalemia lead to cardiac arrest?
Normal levels of potassium are between 3.5 and 5.2 mEq/dL. Hyperkalemia refers
to potassium levels higher that 5.2 mEq/dL. A major function of potassium is to conduct
nerve impulses in muscles. Too low and muscle weakness occurs and too much can
cause muscle spasms. This is especially dangerous in the heart muscle and an irregular
heartbeat can cause a heart attack.
4. The body uses the Protein Buffering System, Phosphate
Buffering System, and Carbonic Acid-Bicarbonate System to
regulate and maintain homeostatic pH, what is the
consequence of a pH imbalance?
Proteins contain many acidic and basic group that can be affected by pH
changes. Any increase or decrease in blood pH can alter the structure of the protein
(denature), thereby affecting its function as well.
5. Describe the laboratory findings associated with metabolic

Normal ABGs (Arterial Blood Gases) Blood pH: 7.35-7.45 PCO2: 35-45 mm Hg
PO2: 90-100 mm Hg HCO3-: 22-26 mEq/L SaO2: 95-100% Respiratory acidosis and
alkalosis are marked by changes in PCO2. Higher = acidosis and lower = alkalosis
Metabolic acidosis and alkalosis are caused by something other than abnormal CO2
levels. This could include toxicity, diabetes, renal failure or excessive GI losses. Here are
the rules to follow to determine if is respiratory or metabolic in nature. -If pH and PCO2
are moving in opposite directions, then it is the pCO2 levels that are causing the
imbalance and it is respiratory in nature. -If PCO2 is normal or is moving tin the same
direction as the pH, then the imbalance is metabolic in nature.
6. The anion gap is the difference between measured cations
(Na+ and K+) and measured anions (Cl - and HCO3 - ), this
calculation can be useful in determining the cause of metabolic
acidosis. Why would an increased anion gap be observed in
diabetic ketoacidosis or lactic acidosis?
The anion gap is the calculation of unmeasured anions in the blood. Lactic acid
and ketones both lead to the production of unmeasured anions, which remove HCO3- (a
measured anion) due to buffering of the excess H+ and therefore leads to an increase in
the AG.
7. Why is it important to maintain a homeostatic balance of
glucose in the blood (ie describe the pathogenesis of
diabetes)?
Insulin is the hormone responsible for initiating the uptake of glucose by the
cells. Cells use glucose to produce energy (ATP). In a normal individual, when blood
glucose increases, the pancreas is signaled to produced in insulin, which binds to insulin
receptors on a cells surface and initiates the uptake of glucose. Glucose is a very
reactive molecule and if left in the blood, it can start to bind to other proteins and lipids,
which can lead to loss of function. AGEs are advanced glycation end products that are a
result of glucose reacting with the endothelial lining, which can lead to damage in the
heart and kidneys.
8. Compare and contrast Type I and Type II Diabetes
Type I diabetes is caused by lack of insulin. With out insulin signaling, glucose will
not be taken into the cell and leads to high blood glucose (hyperglycemia). Type I is
usually treated with insulin injections. Type II diabetes is caused by a desensitization to
insulin signaling. The insulin receptors are no longer responding to insulin, which also
leads to hyperglycemia. Type II is usually treated with drugs to increase the sensitization
to insulin (metformin), dietary and life-style changes or insulin injections.
9. Describe some reasons for a patient needing dialysis AE IOU -
ac ido s is . E l ec t ro l yt e s , In t ox ic atio n/ In g es tio n, o ve rl o ad , ure m ia. Patie nt s w it h kidney
or heart failure. A build up of phosphates, urea and magnesium are removed
from the blood using a semi-permeable membrane and dialysate. AEIOU: A—acidosis; E
—e l ec t ro l y t es p rinc ip all y hype rkal e m i a; I—ing e s tio ns o r o ve rdo se o f m ed ic atio ns / d rugs ;
O —ove rl o ad o f flu id c aus ing he art fa il ure ; U—u re m i a le ad ing t o encep hal itis / pe ric ard itis .
10. Compare and contrast hemodialysis and peritoneal dialysis.
What are some reasons for a patient choosing one over the
other?
Hemodialysis uses a machine to pump blood from the body in one tube while
dialysate (made of water, electrolytes and salts) is pumped in the separate tube in the

opposite direction. Waste from the blood diffuses through the semipermeable
membrane separating the blood from the dialysate. Peritoneal Dialysis does not use a
machine, but instead injects a solution of water and glucose into the abdominal cavity.
The peritoneum acts as the membrane instead of dialysis tubing. The waste products
diffuse into the abdominal cavity and the waste solution is then drained from the body.
Peritoneal dialysis offers continuous filtration and is less disruption to the patient’s daily
routines. However, it does require some training of the patient and is not recommended
for individuals who are overweight or have severe kidney failure. Hemodialysis provides
medical care, but 3 times a week for several hours sitting at a hospital or clinic.
Individuals with acute kidney failure are recommended to use hemo
11. Essential Question: How does homeostasis and maintaining
optimal physiological health impact your wellbeing?
Homeostasis acts to create a constant and stable environment in the body
despite internal and external changes. Proteins and other cellular processes require
optimal conditions in order to carry out their functions. Alterations in pH, salt
concentration, temperature, glucose levels, etc. can have negative effects on health, so
it is vital for mechanisms that regulate homeostasis to function properly for maintaining
good health.
Lesson 2: Cellular Response and
Adaptation
1. Differentiate between Innate Immunity and Adaptive
Immunity.
The innate immune system encompasses physical barriers and chemical and
cellular defenses. Physical barriers protect the body from invasion. These include things
like the skin and eyelashes. Chemical barriers are defense mechanisms that can destroy
harmful agent. Examples include tears, mucous, and stomach acid. Cellular defenses of
the innate immune response are non-specific. These cellular defenses identify
pathogens and substances that are potentially dangerous and takes steps to neutralize
or destroy them. Adaptive immunity is an organism’s acquired immunity to a specific
pathogen. As such, it’s also referred to as acquired immunity. Adaptive immunity is not
immediate, nor does it always last throughout an organism’s entire lifespan, although it
can. The adaptive immune response is marked by clonal expansion of T and B
lymphocytes, releasing many antibody copies to neutralize or destroy their target
antigen.
2. What is a way that Adaptive Immunity can recruit innate
immunity?
The innate immune response to microbes stimulates adaptive immune responses
and influences the nature of the adaptive responses. Conversely, adaptive immune

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responses often work by enhancing the protective mechanisms of innate immunity,
making them more capable of effectively combating pathogenic microbes.
3.3. Why are some infections harder on children while other
infections are harder on the elderly?
Children have not been exposed to many pathogens yet, so they lack memory cells and have not built-
up immunity yet. The elderly have a depleted naïve T cell population from years of battling infections, so the
likelihood of getting a match is less.
4. Describe how and why our injury response results in the
signs of redness, swelling, heat, and pain? Be sure to use
chemokines, histamine, and vasodilation in your response.
An injury causes an inflammatory response which is responsible for the redness,
swelling, heat and pain. Upon injury, cells on the surface begin to release chemokines
which act as messengers that something has happened. Mast cells are also alerted to
release histamines which travel to the endothelial cells of capillaries and causes
vasodilation, which is related to swelling and redness. Vasodilation also causes the
capillaries to become leaky which allows for histamines, chemokines and even pathogen
particles to enter the blood stream where they are met by neutrophils (non-specific)
which start to adhere to the capillary wall and squeeze through the leaky holes
(diapedesis or extravasation) to phagocytose pathogens and damaged cells. Dendritic
cells just under the surface of skin are also activated to phagocytose foreign particles.
Other B cells, T cells (specific) and the complement system also squeeze through the
capillary wall to create an area of congestion.
5. Explain dominant vs recessive genetic diseases. What is a
"carrier" in recessive genetic diseases?
The human genome contains 23 pairs of chromosome (22 autosomes and 1 pair
of sex chromosomes). The pairs are homologous and contain the same genes in the
same order. This means that every gene has a copy, one inherited from your mother
and the other from your father. Not all versions of a gene (alleles) are treated the same
by the cell. Some are expressed over others. A dominant gene is a gene that is
expressed, even if you only have one copy. The dominant gene will be expressed over
the recessive gene, which must have two copies to be expressed. In a dominant genetic
disease, all it takes is one copy of the disease to have the disease. Recessive genetic
diseases require that the individual gets two copies of the gene to have the disease.
Someone who is a carrier for a recessive genetic disease is healthy, but contains a copy
of the disease gene, potentially passing it to their offspring.
6. Describe how to determine the probability of clinical
outcomes given information about the parents (eg two
heterozygous carriers of sickle cell disease)
Punnett Squares can be used to determine the potential probabilities of certain
traits being passed to offspring. If you know the genotypes of each parent (ie

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homozygous or heterozygous for the trait), you can determine the possible outcomes.
Heterozygous means that the parent has one copy of each gene, homozygous means
the parent has the same copy for each gene (either both dominant genes or both
recessive genes).
7. What are some of the consequences of alcohol exposure in
pregnancy?
ND-PAE (neurobehavioral disorder-prenatal alcohol exposure) can cause birth defects and
developmental disabilities (fetal alcohol spectrum disorders-FASDs). Affects thinking and memory, causes
behavioral issues and linked to trouble with everyday functioning
8. What are some of the distinctive features associated with
trisomy 21, or Down's Syndrome? Why is increased maternal
age a risk factor?
Distinct features of Down’s syndrome include intellectual disabilities and common physical features
that include slanted eyes, flattened bridge of the nose and forehead, short in stature, poor muscle tone, loose
joints and single palmar crease. As a woman’s eggs age, they can have mistakes in meiosis potentially leading
to a nondisjunction event causing trisomy 21
9. What is Spina Bifida? Why are relative deficiencies in Folic
acid or B12 associated with Spina Bifida?
Failure to close the neural tube early in gestation due to low folic acid and B-12. These vitamins help
activate DNA synthesis in the developing fetus in the first 4 weeks of pregnancy, that are responsible for
closing up the spinal column. Three types of spina bifida. 1) spina bifida occulta (most common, less severe)
2) Meningocele (least common) 3) Myelomeningocele (most severe).
10. Essential Question: How does the body's cellular responses
and adaptations react to disruptions?
The body uses the RAAS system to regulate blood volume and pressure, the
immune response reacts to fight infection, the inflammatory response reacts to injury
Lesson 3: Musculoskeletal
Pathophysiology
1. Describe how calcitonin, parathyroid hormone, and
calcitriol (Vitamin D) work together to maintain normal
blood calcium levels.
Pages 926, 968, and 980 of text. Vitamin D: UV light stimulates formation of cholecalciferol, which
is hydroxylated in the liver and the kidney into the active form of Vitamin D, calcitriol. Calcitriol
stimulates absorption of calcium and phosphorus from the GI tract in the intestine and phosphate in
the kidney. Calcitriol increases the calcification of osteoid. Calcitriol also stimulates the formation of
bone by raising the levels of calcium and phosphorus in the blood. Low vitamin D levels can cause
hypocalcemia, which stimulates the parathyroid gland to release parathyroid hormone (PTH). PTH
stimulates osteoclasts to resorb bone calcium to increase blood calcium levels. PTH also stimulates

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osteoblasts to form bone. PTH stimulates kidneys to reabsorb calcium into the blood and to
synthesize vitamin D. When blood calcium gets too high, the thyroid is stimulated to release
calcitonin (suppresses osteoclast activity and calcium will be used to form bone).
2. Describe the function of osteocytes within lacunae of bone
Osteocytes absorb nutrients from the bloodstream and distribute them within the bone structure.
Osteocytes absorb waste products from the bone and excrete them into the bloodstream.
3. Describe bone remodeling. Which cells are involved in this
process and what is their function?
Osteoclasts breakdown older bone structure and secrete the release calcium into the bloodstream.
Osteoblasts absorb calcium from the bloodstream and use it to build new bone structure. Working together,
these two cell types allow for regeneration of damaged bone structure.
4. Describe the process of articular degeneration. Which cells
are involved in this process and what is their function?
Articular Degeneration is the thinning and breakdown of the articular cartilage
that covers joints and acts as a lubricant and cushion. This articular cartilage is
comprised of chondrocytes in a matrix of collagen and aggrecan. The chondrocytes
produce enzymes and other proteins that slowly break down and reform the matrix,
allowing for regeneration. Stress caused by being overweight or physical trauma can
cause chondrocytes to speed up the matrix breakdown process relative to the
reformation process, leading to a thinning of the articular cartilage.
5. What is rickets? How does it develop? Who usually develops
rickets? How can rickets be treated?
Pages 979-980 of text. Rickets is, primarily, due to a deficiency of vitamin D (due to sunlight
exposure), which leads to a deficiency of blood calcium. Rickets can lead to bone weakness, deformity, and
susceptibility to fracture. Rickets results from a failure to calcify osteoid due to low amounts of blood calcium
and low vitamin D (typically). There are many different types of rickets. Children, especially under age 2, are
most likely to be diagnosed with rickets. Infants can develop rickets if their mother's diet was low in vitamin D
or in calcium, and breastmilk is low in vitamin D, so mother and baby need to supplement vitamin D (and
calcium). The best way to treat rickets is to prevent it by taking supplements of vitamin D and calcium, eating
food/drink containing vitamin D/calcium, and getting sufficient sunlight. Physical therapy with weight-bearing
exercise can help to treat rickets, as well. It is a multi step process to make the active form of Vit D
6. How does Denosumab treat osteoporosis?
Denosumab is a monoclonal antibody that binds to osteoclasts and inhibits their Calcium-withdrawing
capability.
7. Distinguish between open reduction and internal fixation
(ORIF) and hip replacement surgery.
Open reduction and internal fixation involves “surgical opening’ and insertion of hardware into the
patient that assists with maintaining proper bone alignment during the healing process. Hip replacement
involves replacement of a fractured hip joint with a prosthesis.
8. What is degenerative disc disease? What are some of the
anatomical features of degenerative disc disease? What are
some symptoms of lumbar vs. cervical degenerative disc
disease?

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2022-2023 WGU D236 Pathophysiology Exam - Study Guide with Answers (108 Solved Questions)

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