Physiology of Blood and Respiratory System

Importance of ATP and Oxidative Phosphorylation

• Oxidative metabolism produces 95% of ATP
• 20 times more ATP is produced compared to anaerobic metabolism
• Lack of oxygen results in less energy and more lactic acid waste.

Metabolic Acidosis

• Excessive acid buildup or excessive bicarbonate loss
• Check the anion gap to identify the cause.
• Low pH, normal or slightly elevated carbon dioxide, low bicarbonate are common indicators
• Differences in cation and anion ratios help determine if the acidosis is from acid buildup (H+) or bicarbonate loss (HCO3-)
• Normal anion gap is approximately 12 mmol/L.
• Normal anion gap includes conditions like chronic diarrhea, pancreatic issues, and renal tubular acidosis.
• Elevated anion gap indicates issues like lactic acidosis, ketoacidosis, other renal failures, medications, or inherited metabolic disorders.

Metabolic Alkalosis

• Loss of acid from the blood results in excess bicarbonate.
• Excessive vomiting, hyperaldosteronism, and diuretics can cause this.
• High pH, normal carbon dioxide, and high bicarbonate levels are indicative of this condition.

Respiratory Acidosis

• Excessive carbon dioxide buildup.
• Conditions like hypoventilation (drugs, medications, CNS depression), diffusion issues, and obstructive lung diseases can cause this.
• Low pH, high carbon dioxide, and normal bicarbonate are common indicators.

Respiratory Alkalosis

• Excessive carbon dioxide loss.
• Hyperventilation (altitude, panic attacks) is the most common cause.
• High pH, low carbon dioxide, and normal bicarbonate are characteristic.

Oxygen Carrying

• PaO2 is the partial pressure of oxygen in arterial blood.
• Oxygen content measures how well oxygen moves from the lungs into the bloodstream and is transported to the body.
• Oxygen saturation is the percentage of hemoglobin sites carrying oxygen to tissues.
• Oxygen affinity refers to the tendency of hemoglobin to bind to oxygen.

Oxygen-Hgb Dissociation Curve

• Right shift means oxygen leaves hemoglobin and goes to tissues in cases of lactic acid buildup, DKA, diarrhea, or excessive CO2 retention (meaning the body needs to release the oxygen quickly). Reduced Hb-O2 affinity occurs with lower pH (acidosis), higher CO2, and higher temperature.
• Left shift means oxygen stays bound to hemoglobin, making it difficult to release oxygen to tissues in cases of alkalosis, low temperature, and low CO2. Increased Hb-O2 affinity occurs with high pH (alkalosis), low CO2, and lower temperature.

Hypoxemia

• Hypoxemia is low blood oxygen.
• Common causes are hypoventilation, diffusion impairment, ventilation/perfusion mismatch, and shunting.

Filtration and Reabsorption

• Filtration moves fluid out of the vascular space (capillaries). Capillary hydrostatic pressure is the major driving force.
• Reabsorption moves fluid back into the vascular space(capillaries). Capillary oncotic pressure is the dominant force.
• Albumin, a protein produced in the liver, is the major component of this force.

RAAS

• RAAS is a mechanism that maintains balanced blood pressure (BP) and tissue perfusion.
• Overactive RAAS can result in increased salt and water retention leading to higher blood vessel tone.
• Involves renin, angiotensinogen, angiotensin I, and angiotensin II; ultimately leading to aldosterone from adrenal cortex.

ADH

• ADH (antidiuretic hormone) regulates water balance.
• Detects changes in plasma osmolality (and plasma volume, too)
• Stimulates water retention in kidneys.
• Also called vasopressin.

RBC's and EPO

• Red blood cells (RBCs) are produced in bone marrow.
• Erythropoietin (EPO) is produced in the kidneys.
• EPO stimulates RBC production.

Anemia

• Anemia is a deficiency of red blood cells or hemoglobin.
• Possible causes include iron deficiency, B-12 deficiency, hemolysis, cancers, sickle cell disease, renal disease, and liver disease.
• Symptoms include fatigue, tachycardia, DOE, diaphoresis, leg cramps, insomnia.
• Lab values like CBC, Hgb, Hct, MCH, MCV, and iron levels are used for diagnosis.
• Types include microcytic hypochromic (small cells, low color), macrocytic normochromic (large cells, normal color), and normocytic normochromic (normal cells, normal color).

Clotting Factors

• Clotting factors are primarily produced in the liver, except factor VIII which is produced by the endothelium.
• Low or missing clotting factors increase bleeding risk.
• PT/INR and PTT tests measure clotting factors in the extrinsic and intrinsic pathways, respectively.

Sickle Cell Disease

• Inherited disorder.
• Proteins polymerize, causing RBCs to sickle.
• Symptoms include bilateral pain, extremity edema, acute chest syndrome, glomerular disease, and infection.

Inflammatory Response

• Initial response to injury/threat, involving various barriers, inflammatory responses, and acquired immunity.
• Characteristics of inflammatory response include speed, specificity, cells, memory, peptides, and protection.
• First, second, and third lines of defense are involved.

Antibodies

• Antibodies bind pathogens and cause them to clump together, thus promoting their removal via phagocytosis.
• Neutralization, agglutination, and precipitation are ways antibodies directly protect.
• Activation of the complement system and opsonization are antibody-mediated indirect protection mechanisms.
• Coating can help to avoid destruction by phagocytes.

Septic Shock

• Septic shock is a severe life-threatening condition.
• Caused by gram negative bacteria infection producing endotoxins, causing inflammatory tissue injuries and organ failure.
• Massive cytokines release leading to multi-organ failure

Viral Infections

• Viruses requires host cell reproduction.
• HIV, CD4 lymphocytes commonly infected cells.
• AIDS diagnoses typically shows a CD4 cell count of less than 200 cells/mm3.
• Viral symptoms may include anorexia, weight loss, Kaposi sarcoma, herpes, cytomegalovirus, retinitis, and thrush, among others.

Hypersensitivity Reactions

• Antibody mediated & cells mediated. Antibody-mediated types include type I (allergies, anaphylaxis), type II (tissue specific), and type III (antigen-antibody complexes). Cell-mediated type is type IV.

Type I Hypersensitivity Reactions (Anaphylaxis)

• Causes include allergen exposure resulting in mast cell or eosinophil degranulation, leading to immediate symptoms.
• Symptoms include release of histamine and other inflammatory mediators.

Cardiac Terms

• Preload is the filling pressure during diastole (relaxed phase of the heartbeat), influenced by blood volume and blood pressure.
• Contractility refers to how well the heart muscle contracts.
• Afterload is the pressure the heart must overpower to pump blood out (systemic vascular resistance).
• Left ventricle has highest pressure when pumping blood to the rest of the body.

Coronary Artery Disease (CAD)

• CAD is a condition where coronary arteries become narrowed or obstructed by plaque build-up.
• Resulting in myocardial ischemia (deprivation of blood to myocardium)
• Possible result is myocardial infarction.

Atherosclerosis

• Atherosclerosis involves cholesterol accumulation and inflammation in blood vessel walls causing plaque formation.
• This plaque can cause significant problems if it obstructs or narrows the blood vessels.

Atelectasis

• Atelectasis describes the collapse of alveoli (tiny air sacs in the lungs).
• Causes include reduced ventilation or reabsorption of air.
• Risk factors include bed rest, infection, illness.

Pulmonary Embolism

• A pulmonary embolism (PE) occurs when a blood clot travels to the lungs and blocks blood flow.
• Known risk factors commonly include hypercoagulability, venous stasis, and vessel injury (Virchow's triad).

Pneumonia

• Infections of the lungs: Viral, bacterial, or fungal origin (many causes).
• Alveoli filled with purulent fluid.
• Pneumonia can cause symptoms like tachypnea, dyspnea, chest pain, and increased dead space, V/Q imbalances, and decreased PaO2.

COPD

• COPD is a broad term describing lung diseases characterized by progressive airway obstruction.
• Chronic bronchitis, emphysema and some instances of refractory asthma are included in the definition of COPD.
• Associated causes include long-term exposure to irritants and environmental factors, as well as genetic predisposition.

Acute Kidney Injuries

• Acute kidney injury (AKI) involves decreased glomerular filtration rate (GFR) and urine output with accumulation of nitrogenous wastes (urea and creatinine) in the blood.
• Classifications are prerenal (inadequate perfusion), intrarenal (kidney damage), and postrenal (obstruction).

Thyroid and Parathyroid Conditions

• Conditions involving hypothyroidism (low thyroid hormone) or hyperthyroidism (high thyroid hormone).
• Conditions are defined as primary (originating in thyroid gland) or secondary (originating outside thyroid gland).

Adrenal Crisis

• An adrenal crisis involves life-threatening adrenal insufficiency due to low cortisol or low aldosterone secretion.

Diabetes Mellitus

• Type I diabetes is considered an autoimmune disease. The cause appears to be some viral trigger.
• Type II diabetes is considered a result of insulin resistance. Both can result in issues with blood glucose levels.
• Possible consequences include high blood glucose, DKA, and potential organ damage over time.

GI Issues

• Issues are frequently found in upper and or lower GI tract.
• Conditions can cause bleeding, obstructions, and inflammation as causes that lead to multiple symptoms.

Cerebral Vascular Disease

• Abnormal brain function due to disruptions in blood vessels can cause various neurological issues including possible strokes.
• Causes include abnormal vessel wall, vessel occlusion, vessel rupture, and blood abnormalities.

Delirium vs. Dementia

• Delirium is a temporary disturbance of brain function that causes issues with attention, awareness, and thinking. Likely caused by a medical issue (like infections, dehydration, electrolyte imbalances, or other causes). It can be brief (sometimes hours up to weeks), and usually reversible.
• Dementia is a progressive decline in cognitive function that affects several domains, such as memory, language, and problem-solving over time. Chronic in nature, not reversible.

This quiz covers essential concepts related to blood physiology and respiratory function, including conditions like hypoxia, anemia, and atherosclerosis. Test your knowledge on how these conditions affect overall health and their underlying mechanisms. Dive into key physiological processes related to red blood cell production and the cardiovascular system.