Patho Exam 1

What cells of the immune system belong to the myeloid cell line?

The cells of the immune system that belong to the myeloid cell line are neutrophils, basophils, eosinophils, mast cells, macrophages, and dendritic cells.

What cells of the immune system belong to the lymphoid cell line?

The cells of the immune system that belong to the lymphoid cell line are B-cells, T-cells, and natural killer cells.

Which cells are granulocytes, and what do they do in the body? Why are Mast cells different from other granulocytes? What role do Mast cells play in allergic reactions and asthma? 

Neutrophils, eosinophils, basophils, and mast cells are granulocytes and these cells that release enzymes and cytokines during infections and diseases, which fight pathogens. Mast cells are different from other granulocytes because they are not polymorphonuclear leukocytes (PMNs) and are involved in the tissues of the body. Mast cells release histamine, which contributes to inflammation in the body by swelling and turning red and asthma by dilating the blood vessels which lead to swelling in the airway.

What is the complement cascade? What are cytokines and what purpose do they serve in the immune response? 

Complement cascade is a series of proteins that serves as a defense system against pathogens and it has three pathways: classical, MB-Lectin, and Alternative. The classical pathway is when an antigen and antibody bind together, complement activates, then recruit inflammatory cells (PMNs and monocytes). The MB-Lectin pathway is when lectin binds to a pathogen surface, complement activates, then opsonization to cover the pathogen in opsonin so pathogens can ingest them. The Alternative pathway is the pathogen surface because there is no specific protein for them then the Membrane Attack Complex (MAC) pokes holes in the pathogen and dies. 

Cytokines are small proteins that are released when pathogens are present to signal to other immune cells to come to that specific site to protect and repair the body.

Compare/contrast the innate and adaptive immune systems and discuss their role in fighting pathogen invasion. 

The innate immune system is fast, but not specific and adaptive immune systems are slow, but very specific and has memory. The innate system is the first line of defense and are the physical barriers such as the skin, mucous membranes, and saliva and can be bloodborn, which involves the complement cascade and phagocytes. The adaptive immune system involves T-cells and B-cells and there is humoral and cell-mediated immunity.

The adaptive immune system allows the body to remember pathogens that have been previously encountered, and thus mount a faster immune response when it is re-exposed to that pathogen again. This process is mediated in part by antibodies. Active immunity is conferred through natural infection or vaccination, both of which induce antibodies that can respond to a particular pathogen if it is encountered again. So… What is passive immunity? 

Passive immunity is immediate, short-term protection and is conferred naturally when antibodies are passed from mother to baby or when an infected person gets injected antibodies from an immune person.

What does the term “cell-mediated immunity” mean? How about “humoral immunity?” 

“Cell-mediated immunity” is with T-cells and focuses on the cells. “Humoral immunity” is with B-cells and focuses on the blood and extracellular fluids like lymph.

What 3 immune cells are Antigen Presenting Cells (APCs)? Which are part of the innate system (ie: myeloid cell line)? Which are part of the adaptive system (ie: lymphoid cell line)? 

The 3 immune cells that are Antigen Presenting Cells (APCs) are dendritic cells, macrophages, and B cells. Dendritic cells and macrophages are part of the innate system and B cells are part of the adaptive system.

Describe the steps of antigen processing and presentation, and why this process is important in the immune response. Please be sure to include APCs, MHC I and II, T-Helper Cells, T-Cytotoxic Cells, and B-Cells in your answer.  

The APCs are macrophages, dendritic cells, and B cells (for the adaptive system). These APCs then perform phagocytosis, where they will “eat” the pathogens. The antigens from the APCs will then enter either of the two pathways: MHC I pathways and MHC II. The MHC I pathway is when it involves an intracellular problem such as cancer, cellular damage, and intracellular infection and recruits the CD8 T-killer cell which destroys viral infected cells and tumors. The MHC II pathway is when it involves an extracellular problem such as bacteria and toxins and recruits the CD4 T-helper cell which assists other lymphocytes to fight the infection site.

What are immunoglobulins? What role do they play in the immune response? What do “titers” tell us about a person’s immune response and the timing/duration of pathogen infection (think about IgG and IgM)? 

Immunoglobulins are another word for an antibody. They are Y-shaped proteins that identify and attack foreign objects. A titer measures the concentration of antibodies a person has. For example, IgG is the “memory” antibody and IgM is the “first responder” antibody. In the beginning of a pathogen infection, there will be a high concentration of IgM and no IgG and vice versa.

Myeloproliferative disorders cause excessive proliferation of certain cells from the myeloid cell line. They can be primary or secondary. What’s the difference? 

Primary is cancerous and caused by mutations such as JAK2 mutation in Polycythemia Vera and secondary is non-cancerous and caused by an overproduction of something.

Briefly describe the pathogenesis each of the following myeloproliferative diseases:

1. Polycythemia Vera

Excessive production of red blood cells (RBCs)

2. Essential Thrombocythemia 

Excessive production of platelets

3. Chronic Myeloid Leukemia 

Excessive production of granulocytes

There are several different types of Leukemia. How are leukemias generally classified? 

Leukemias are generally classified by the cell line that is affected (myeloid cells vs lymphoid cells) and whether it is acute, short-term, or chronic, long-term.

To determine the underlying cause of anemia due to a decreased production of RBCs, we can evaluate the size and color of red blood cells. Please identify and briefly describe the test that indicates RBC size and the test that indicates RBC color. 

The test that indicates RBC size is the Mean Corpuscular Volume (MCV) and that measures the average concentration of hemoglobin of RBCs. The test that indicates RBC color is the Mean Corpuscular Hemoglobin Concentration (MCHC) and that specifically measures the average amount of hemoglobin in 100 mL of red blood cells in percentages.

To determine whether anemia is due to increased destruction of RBCs, we often perform a Reticulocyte Count. What does an elevated Retic Count indicate? What does a decreased Retic Count indicate? 

Reticulocytes are immature RBCs made in the bone marrow. An elevated Retic Count indicates that there is an increased destruction of RBCs because the bone marrow is working hard to replace the RBCs. A decreased Retic Count indicates that there is a decreased production of RBCs.

When an anemia occurs due to decreased production of red blood cells, the reticulocyte count will be decreased (this is because the body cannot increase the number of reticulocytes due to having a “production problem”). Decreased production of RBCs can be due to major problems within the bone marrow, energy diversion away from making RBCs due to other chronic diseases, and various vitamin deficiencies. Name one condition that can cause anemia in each of these categories. 

Bone marrow - Leukemia, a cancer on the marrow and overproduction of abnormal white blood cells

Chronic diseases - Renal disease, it affects the kidney’s function

Vitamin deficiencies - Pernicious anemia, vitamin B-12 deficiency 

Describe the pathogenesis of Sickle Cell Disease

Sickle Cell Disease is genetically inherited and it is caused by a mutation in the Hemoglobin S (HbS). The hemoglobin would lose its ability to carry oxygen then clumps together to make a “sickle” shape. Sickle cells would break down ina  process called “hemolysis” and cause anemia.

Describe the complications that occur during a sickle cell crisis 

The complications that occur during a sickle cell crisis are painful swelling, damage to the spleen when fighting infections, and severe infections.

Name the priority interventions for patients in sickle cell crisis

The priority interventions for patients in sickle cell crisis are a bone marrow transplant, so the stem cells have new red blood cells, platelets, and white blood cells and use zinc-finger nuclease to cut and correct the mutation.

Von Willebrand Disease 

The coagulation factor that is impacted is the Von Willebrand factor. This affects anyone and is the most common disorder.

Hemophilia 

The coagulation factors that are impacted are Factor VIII and Factor IX. The population most affected is the male population.

Hemorrhagic Disease of the Newborn 

The supportive vitamin that is impacted is vitamin K. This disease is caused by a vitamin K deficiency and affects newborns.

A child presents for care with a chief complaint of a very painful swollen knee that appeared suddenly after a very minor trauma. He is very hesitant to move the knee or let you touch it. What condition do you suspect based on his initial presentation? What intervention would you expect to initiate right away in order to manage symptoms associated with this condition? 

The condition I would suspect based on his initial presentation would be a hemorrhage because the child does not want to move his knee. I would expect to initiate it to elevate the affected area and apply compressions with an ice pack to relieve the pain.

What parts of the body facilitate ventilation (ie: movement of air in and out)? 

The parts of the body that facilitates ventilation are the central nervous system, musculoskeletal system, and upper and lower airways.

What parts/features of the body facilitate the diffusion of gases like O2 and CO2? 

The parts/features of the body that facilitate the diffusion of gases like O2 and CO2 are the alveoli and specifically the acinus (alveoli and respiratory bronchioles), surfactant, and Pores of Kohn.

What parts of the body facilitate perfusion of oxygenated blood to the tissues? 

The parts of the body facilitate perfusion or oxygenated blood to the tissues are capillaries and circulation from right ventricle to pulmonary artery to arterioles to capillaries to venules to pulmonary vein to left atrium to left ventricle to body.

What is hypercapnia? 

Hypercapnia is increased carbon dioxide in the blood.

What causes hypercapnia?

Hypoventilation increases carbon dioxide in the blood.

How does hypercapnia affect blood pH?

The carbon dioxide decreases pH and makes it more acidic (acidosis).

What signs and symptoms are associated with hypercapnia?

The signs and symptoms that are associated with hypercapnia are fatigue, confusion, coma, anxiety, headaches, shortness of breath, and sweating. 

What is hypoxemia? 

Hypoxemia is decreased oxygen in the blood.

What is a ventilation/perfusion (V/Q) mismatch? (describe “dead space” and “shunt” in your answer)

Ventilation/perfusion (V/Q) mismatch is when there is either ventilation (movement of air in and out of alveoli in the lungs) and no perfusion (flow of blood through pulmonary capillaries) or perfusion and no ventilation. Ventilation with no perfusion is dead space and perfusion and no ventilation is shunt.

What signs and symptoms are associated with hypoxemia/hypoxia? 

The signs and symptoms are restlessness, anxiety, tachycardia/tachypnea, bradycardia, extreme restlessness, and dyspnea.

Compare/contrast acute respiratory failure and chronic respiratory failure.

Acute respiratory failure and chronic respiratory failure is similar by the derangements of arterial blood gases, but they differ because acute happens in minutes or hours and chronic happens days, weeks, or months.

Respiratory failure is generally caused by one of two problems: a gas exchange problem (Hypoxemic failure) or a ventilation problem (hypercapnic failure). Briefly describe each. 

A gas exchange problem (Hypoxemic failure) is when arterial oxygen tension is lower than 60 mmHg with normal or low arterial carbon dioxide tension. A ventilation problem is when arterial carbon dioxide tension is higher than 50 mmHg and commonly, hypoxemia.

What are some signs/symptoms of respiratory distress? What are the general approaches to treating respiratory distress?

Some signs and symptoms of respiratory distress are tachypnea (rapid breathing), stridor, wheezing, rales, absent breath, abnormal chest movements, cyanosis, and cold extremities. The general approaches to treating respiratory distress are to provide adequate oxygen, provide ventilation by intubating or suctioning, promote patient movement, and give any treatment to relieve the patient.

COPD is a leading cause of death in the US.  COPD includes a spectrum of obstructive changes in the lung, including features of both emphysema and chronic bronchitis.  In your own words: Please describe the basic pathophysiology of emphysema and chronic bronchitis. 

Emphysema - this is commonly caused by smoking and genetics and it is the permanent enlargement of the alveoli due to destruction of the alveolar wall. Genetically, it is caused by an alpha1 antitrypsin deficiency. For smoking, it increases the number of neutrophils. Both of them involve the release of protease elastase (break down elastin) and inhibition of alpha1 antitrypsin. Leads to “air-trapping” and “barrel chest.”

Chronic bronchitis - this is a cough lasting for at least 3 months in 2 years with sputum. It affects the bronchi and bronchioles and can also be caused by smoking. Sputum clogs the airways in both directions (not even inhaling and trapping air)  and can cause hypoxia which can then lead to cyanosis.

Asthma is an extremely common obstructive disease that affects children and adults. In general terms, please describe the pathophysiology of asthma, then describe the pathophysiology of an acute asthma attack. 

Asthma is when there is a resistance during expiration and inflammation of the airways which can lead to hyperesponsiveness or more effort to breathe. 

An acute asthma attack is when the airway suddenly narrows due to a trigger like pollen, dust, or smoke and this leads to a rapid decrease of airflow.

Both COPD and Asthma can be life-threatening, and thus it is important to prevent worsening of the disease and treat acute exacerbations. What similarities do these conditions share in terms of disease management? How are these conditions different in terms of disease management?  

They are similar in having similar triggers that cause these obstructive airway diseases like smoking, for example. They all would need to avoid triggers, vaccination, antibiotics and ventilatory support, and oxygen therapy. They are different in terms of disease management because the primary goal for asthma is to control inflammation and prevent airway hyperactivity and the primary goal for COPD is to prevent symptoms from worsening. Asthma can be reversible with an inhaler while COPD is not as easily reversible.

Briefly describe the 5 major types of pleural effusion.

Transudate - increased hydrostatic pressure (pressure exerted by fluid out of capillaries) or decreased oncotic pressure (pulling fluid in capillaries)

Exudate - inflammation which increase capillary permeability and allow leaks into pleural space

Empyema - infection of pleural space from bacteria

Hemothorax - bleeding into the pleural cavity

Chylothorax - lymphatic obstruction or leakage into pleural space

Compare and contrast an open pneumothorax to a closed pneumothorax.

Both open pneumothorax and closed pneumothorax involve air entering the pleural space by a rupture. However, open is when there is an external opening such as a stab wound, gunshot wound, or surgical injury and closed does not have an external opening.

Describe the pathophysiology of tension pneumothorax and explain why it is a medical emergency that can lead to death if uncorrected. 

A tension pneumothorax is when air enters the pleural space, but the air does not have a way to get out. This is a medical emergency that can lead to death if uncorrected because this collapses the lungs and compresses the heart which impairs the heart from filling and pumping.

What are the parts of a feedback loop? 

The parts of a feedback loop are the stimulus, sensor, control, and effector. The stimulus is the cause that disrupts the body’s “set point.” The sensors are the receptors that receive this information and signal it to the control center. The control center receives the information from the sensors then releases the response. Finally, the effectors carry out the response to restore the body back to its “set point.”

What’s an example of a positive feedback loop? How about a negative feedback loop? 

An example of a positive feedback loop is childbirth because the contractions amplify as the baby comes out. An example of a negative feedback loop is sweating when you are hot to decrease the body’s temperature and return to the body’s normal temperature.

Briefly describe each of the following mechanisms of stress adaptation and name the primary stress hormones involved in each system:

HPA Axis: The primary stress hormone of the HPA Axis is cortisol. The body releases cortisol when exposed to higher levels of stress to calm the body down. It provides energy and stabilizes blood pressure. 

SAS: The primary stress hormones of SAS are epinephrine and norepinephrine. These are the “fight-or-flight” hormones and they are the reason for “adrenaline rush.” It dilates the bronchioles, increases blood flow, and increases heartbeat.