Understanding the Physiology of Disease

Physiology

Q1

Case A: 45-year-old Female with a Broken Right Ulna

a.

The most logical size difference when you look at the left and right arms is muscle atrophy in the right arm, due to being immobilized in a cast for five weeks. The muscles of the right arm would appear smaller compared to those in the left arm. This is a common enough phenomenon, as muscles that are not regularly used tend to lose mass (Rogers, 2022).

b.

The tissue that changed in size is the skeletal muscle tissue. Muscle atrophy affects the muscle fibers. In turn there is a reduction in muscle mass, muscle strength, and muscle size. There can also be some alteration in the connective tissues surrounding the muscles, but the skeletal muscle tissue is the main tissue involved (Rogers, 2022).

c.

The type of cellular adaptation that occurred is atrophy, which is a decrease in cell size, which leads to a reduction in the overall size of the affected organ or tissue. In this case, the immobilization of the arm resulted in atrophy from disuse of the skeletal muscles (Rogers, 2022).

d.

In terms of molecules, one would see a reduction in the synthesis of structural proteins like actin and myosin, which allow muscle contraction. There would be an increase in protein degradation pathways, such as the ubiquitin-proteasome pathway, which breaks down muscle proteins.

On the level of organelles, atrophy results in a decrease in the number and size of mitochondria in the muscle cells, as there is less energy demand due to reduced activity. As mitochondrial content decreases, the cell\\\'s capacity for ATP production is reduced (Rogers, 2022).

At the cellular level, the muscle fibers (myocytes) shrink as their protein content lessens. There is also a reduction in overall cellular metabolism, with fewer energy-producing organelles. Cells can undergo autophagy, wherein they digest their own organelles to adapt to the decreased need for cellular machinery (Rogers, 2022).

In terms of tissue, skeletal muscle fibers become thinner, and the overall muscle mass of the right arm decreases. This tissue-level change is seen as muscle wasting away and accounts for the observable difference in arm size.

Case B: 68-year-old Male with Atherosclerotic Occlusion in an Artery to His Left Leg Calf Muscle

e.

The most logical form of cellular injury in this case is ischemic injury, which is a type of hypoxia caused by atherosclerotic occlusion of the artery. The reduction of blood flow prevents oxygen and nutrients from getting to the calf muscle tissue. If it goes on long enough, ischemia can lead to cell death (Rogers, 2022).

f.

In terms of ions, ischemic injury results in a failure of the sodium-potassium (Na+/K+) pumps due to the lack of ATP. There is an influx of sodium and water into the cells, causing swelling. Calcium ions also accumulate inside the cell due to dysfunction in calcium pumps, which further damages the cell and its organelles (Rogers, 2022).

At the molecular level, there is a decrease in ATP production as oxidative phosphorylation in the mitochondria is impaired by the lack of oxygen. The cell shifts to anaerobic glycolysis. Lactic acid builds up as intracellular pH balance is lost.

Regarding organelles, the mitochondria are one of the first to be affected by the lack of oxygen. Mitochondrial damage leads to a further decrease in ATP production and the release of pro-apoptotic factors which initiate programmed cell death if the injury persists. The endoplasmic reticulum also becomes stressed, impairing protein synthesis (Rogers, 2022).

At the cellular level, the injury manifests as cell swelling, loss of membrane integrity, and potential cell death if the ischemia is severe and prolonged. If the blood supply is not restored, irreversible injury occurs.

In terms of tissue, prolonged ischemia leads to the breakdown of muscle fibers and tissue necrosis. The affected area may become discolored due to the death of the cells and tissues, and there may be subsequent inflammation as immune cells respond to clear the dead cells. Eventually, scar tissue can form in the area, replacing the damaged muscle tissue (Rogers, 2022).

Q2

Part A: Health Condition Selected – Chronic Kidney Disease (CKD)

The health condition I selected from the \\\"Health Conditions\\\" category of Healthy People 2030 is Chronic Kidney Disease (CKD). CKD is a condition in which the kidneys gradually lose their ability to filter waste and excess fluid from the blood. It affects millions of people, especially people with diabetes and high blood pressure (Healthy People 2030, 2024; Mini-Tutorial 1: Healthy People 2030 Studyguide and lecture notes, 2024).

Part B: Three Related Core Objectives

1. Objective CKD-01: Reduce the proportion of adults with chronic kidney disease

· Status: Improving (Green Symbol)

This objective focuses on lowering the number of adults who develop CKD. Healthy People 2030 shows that the incidence of CKD has been on a decline, but underserved populations like low-income communities and minorities are still disproportionately affected. This objective recommends early diagnosis and preventive care to manage risk factors that lead to CKD (Healthy People 2030, 2024).

2. Objective CKD-04: Increase the proportion of people with chronic kidney disease who know they have impaired kidney function

· Status: Little or No Detectable Change (Yellow Symbol)

This objective focuses on raising awareness of CKD by focusing on early detection. Many people with CKD do not know they have it. Improving access to testing and routine medical check-ups in underserved populations is a priority to help more people catch and manage CKD early on (Healthy People 2030, 2024).

3. Objective CKD-05: Increase the proportion of adults with diabetes who get at least annual urinary albumin tests

· Status: Improving (Green Symbol)

This objective recommends annual screening for kidney disease in people with diabetes. Regular urinary albumin testing can identify early signs of kidney damage. The status indicates that this screening is common where there is good access to healthcare, but there is still room for improvement, particularly among underserved minority populations (Mini-Tutorial 1: Healthy People 2030 Studyguide and lecture notes, 2024).

Part C: Application of Healthy People 2030 to the Advanced Practice Nurse (APN) Role

How can the advanced practice nurse (APN) use Healthy People 2030 in their work?

Advanced practice nurses (APNs) can use Healthy People 2030 as a guide for developing evidence-based interventions that address individual needs and public health needs. For example, an APN working in a primary care setting can use the objectives related to CKD to guide clinical practice by focusing on prevention, early detection, and management of risk factors like diabetes and hypertension. APNs can also focus on reducing the incidence of CKD in the community through advocacy work (Healthy People 2030, 2024).

Accessing and utilizing Healthy People 2030 programs

APNs can access the Healthy People 2030 website to review objectives and locate up-to-date data and resources. The website gives guidelines and strategies for APNs to use in their daily practice. For example, APNs can use the CKD-05 objective on urinary albumin testing to make sure their patients with diabetes receive annual kidney function screenings. APNs can also advocate for community-level interventions by working alongside public health organizations to promote CKD awareness and preventive screenings by way of educational outreach programs targeting at-risk populations (Mini-Tutorial 1: Healthy People 2030 Studyguide and lecture notes, 2024).

Incorporating aspects of Healthy People 2030 into practice

Objectives

The APN can incorporate Healthy People 2030 objectives by setting goals such as implementing protocols to screen all patients with diabetes for CKD.

Leading Health Indicators (LHIs)

LHIs are use to measure progress on priority health issues and APNs can use them for working with patients focused on controlling blood pressure or managing diabetes to reduce CKD risk.

Social Determinants of Health (SDOH)

APNs can apply an understanding of SDOH to address health disparities in their practice by looking at factors that affect the health of low-income communities—such as less access to healthcare, or financial or language barriers (Healthy People 2030, 2024).

Evidence-Based Resources

APNs can use evidence-based resources from Healthy People 2030 in their practice by using up-to-date research or protocols to make sure their care matches the bar set by national health objectives and standards.

Mindful of Diversity and Inclusion

APNs can apply the principles of diversity and inclusion by offering culturally sensitive care by way of sharing educational materials or having interventions that are linguistically and culturally relevant for the people they serve. APNs can also work to reduce healthcare disparities by advocating for policy changes that improve access to CKD screenings.

Q3

a.

Cystic fibrosis is inherited in an autosomal recessive pattern. Both the father and mother are carriers, meaning they each have one normal allele (C) and one defective allele (c) for the CF gene (Rogers, 2022). This is the Punnett square for their offspring:

C (Father)

c (Father)

C (Mother)

CC (Normal)

Cc (Carrier)

c (Mother)

Cc (Carrier)

cc (Affected)

As for recurrence risk, there is a 25% chance the child will be unaffected (CC), a 50% chance the child will be a carrier (Cc), and a 25% chance the child will inherit cystic fibrosis (cc).

b.

Huntington’s disease is an autosomal dominant disorder, meaning only one defective allele (H) is needed to pass on the disease (Rogers, 2022). The father expresses the disease and is heterozygous (Hh). The mother is healthy (hh). The Punnett square is:

H (Father)

h (Father)

h (Mother)

Hh (Affected)

hh (Unaffected)

There is a 50% chance the child will inherit Huntington’s disease (Hh) and a 50% chance the child will be unaffected (hh).

c.

Hemophilia A is an X-linked recessive disorder. The mother is a carrier (X*X) and the father is healthy (XY). The Punnett square is as follows:

X (Father)

Y (Father)

X (Mother)

XX (Unaffected daughter)

XY (Healthy son)

X* (Mother)

X*X (Carrier daughter)

X*Y (Affected son)

There is a 25% chance of a carrier daughter (X*X), a 25% chance of an affected son (X*Y), a 25% chance of a healthy son (XY), and a 25% chance of a healthy daughter (XX).

d.

If the father is heterozygous for an autosomal dominant disease X and two children are unaffected, the probability of the next child inheriting the disease is still 50% because the inheritance of a genetic condition is independent of prior outcomes. The risk stays the same.

e.

The loss of chromosome material is more likely to cause zygote death because missing genetic information typically causes vital proteins and structures to also be missing, and this is usually lethal. On the other hand, the addition of chromosome material will not be as immediately problematic because it may result in excess but functional proteins (Rogers, 2022).

f.

1. Genotype: The genetic makeup of an individual, represented by their alleles (e.g., CC, Cc, or cc).

2. Phenotype: The observable traits or characteristics of an individual resulting from their genotype.

3. Penetrance: The proportion of individuals with a specific genotype who actually express the associated phenotype.

4. Expressivity: The degree to which a genetic trait is expressed in an individual.

Penetrance can vary due to factors like modifier genes, environmental influences, or the specific mutation present.

g.

Turner Syndrome occurs when a female has only one X chromosome (45,X karyotype). It is considered serious because it tends to cause infertility, heart defects, and other developmental problems that stem from a missing second sex chromosome (Rogers, 2022).

h.

Cri du chat syndrome is caused by a deletion of a portion of chromosome 5. This deletion sets off a loss of important genes needed for normal development, which then causes mental disabilities, distinctive facial features, and the characteristic \\\"cry of the cat\\\" sound because of malformed laryngeal conditions (Rogers, 2022).

Q4

a.

Huntington’s disease is inherited in an autosomal dominant pattern: only one copy of the altered gene is necessary to cause the disease, and there is a 50% chance of passing the defective gene to offspring. It is caused by a mutation in the HTT gene located on chromosome 4. The gene mutation involves an abnormal expansion of CAG trinucleotide repeats (Rogers, 2022).

The altered protein is called huntingtin. This protein plays a role in nerve cell function, though its exact function is not fully understood. The defective huntingtin protein accumulates in neurons, leading to cell damage (NIH, 2024).

The accumulation of the defective huntingtin protein causes neuronal death, particularly in the basal ganglia, leading to motor dysfunction, cognitive decline, and psychiatric symptoms. This results in the progressive movement disorder known as chorea and other neurological impairments (Rogers, 2022).

b.

Cystic fibrosis is inherited in an autosomal recessive pattern. Both parents must carry one copy of the defective gene for a child to inherit the disease. It is caused by mutations in the CFTR gene located on chromosome 7. The most common mutation is ?F508, which results in the loss of a phenylalanine amino acid (Rogers, 2022).

The protein affected by this mutation is the cystic fibrosis transmembrane conductance regulator (CFTR) protein. This protein regulates the movement of chloride and sodium ions across cell membranes, which is essential for maintaining fluid balance in tissues (NIH, 2024).

Defective CFTR protein disrupts ion transport, leading to thick, sticky mucus buildup in various organs. This primarily affects the lungs, causing chronic respiratory infections, and the pancreas, leading to malabsorption of nutrients. These symptoms result in life-threatening respiratory and digestive issues (Rogers, 2022).

c.

PKU is inherited in an autosomal recessive pattern. Affected individuals inherit two copies of the defective gene, one from each parent. It is caused by mutations in the PAH gene located on chromosome 12. This gene encodes the enzyme phenylalanine hydroxylase, which is necessary for breaking down the amino acid phenylalanine.

The altered protein is phenylalanine hydroxylase (PAH). Its function is to convert phenylalanine into tyrosine, an important precursor for neurotransmitters (NIH, 2024).

A deficiency in PAH leads to the accumulation of phenylalanine in the blood and brain. High levels of phenylalanine are toxic to the brain and can cause intellectual disability, developmental delays, and neurological problems if untreated (Rogers, 2022).

d.

Hemophilia A is inherited in an X-linked recessive pattern. This means that males (with one X chromosome) are more likely to be affected, while females (with two X chromosomes) are usually carriers. It is caused by mutations in the F8 gene located on the X chromosome. This gene provides instructions for making Factor VIII, a protein involved in blood clotting (Rogers, 2022).

The affected protein is Factor VIII, which is essential for the blood coagulation cascade. Without sufficient functional Factor VIII, the blood cannot clot properly.