Study Guide: The Respiratory, Blood, Cardiovascular, and Vascular Systems

The Respiratory System

Major Functions of the Respiratory System

• Primary Function: To supply the body with oxygen (O2) and remove carbon dioxide (CO2).

• Additional Functions: Involved in speech, olfaction (smell), and regulation of blood pH.

Processes of Respiration

• Pulmonary Ventilation: Movement of air into and out of the lungs (breathing).

• External Respiration: Gas exchange between air in alveoli and blood in pulmonary capillaries.

• Transport of Gases: Movement of O2 and CO2 in the blood between lungs and tissues.

• Internal Respiration: Gas exchange between systemic blood and tissue cells.

Upper and Lower Respiratory Organs

• Upper Respiratory Tract: Nose, pharynx, larynx.

• Lower Respiratory Tract: Trachea, bronchial tree, lungs.

• Bronchial Tree: Series of branching airways including bronchi, bronchioles (contain smooth muscle and cuboidal epithelial cells), and alveoli.

Conducting Zone vs. Respiratory Zone

• Conducting Zone: All respiratory passageways that carry air to the sites of gas exchange (nose to terminal bronchioles); functions in air transport, humidification, warming, and filtering.

• Respiratory Zone: Sites of gas exchange (respiratory bronchioles, alveolar ducts, alveoli).

• Alveoli: Thin-walled sacs specialized for gas exchange; surrounded by capillaries; contain type I (gas exchange) and type II (surfactant-secreting) cells.

The Pleurae

• Visceral Pleura: Covers the lungs.

• Parietal Pleura: Lines the thoracic cavity.

• Pleural Cavity: Space between pleurae containing lubricating fluid to reduce friction.

Homeostatic Imbalances

• Laryngitis: Inflammation of the larynx, often causing voice loss.

• Rhinitis: Inflammation of the nasal mucosa.

• Pleurisy: Inflammation of the pleurae, causing painful breathing.

Respiratory Physiology

Pulmonary Ventilation

• Inspiration: Diaphragm and external intercostals contract, thoracic volume increases, pressure decreases, air flows in.

• Expiration: Muscles relax, thoracic volume decreases, pressure increases, air flows out.

• Gas Law: Boyle's Law applies: $P_1V_1 = P_2V_2$ (pressure and volume are inversely related).

Gas Exchange

• Dalton’s Law: Total pressure of a gas mixture is the sum of the partial pressures of each gas.

• Henry’s Law: The amount of gas dissolved in a liquid is proportional to its partial pressure and solubility.

• External Respiration: Influenced by partial pressure gradients, gas solubility, membrane thickness, and surface area.

• Internal Respiration: Driven by partial pressure gradients between blood and tissues.

Gas Transport

Oxygen Transport

• Transport Mechanisms: 98.5% bound to hemoglobin, 1.5% dissolved in plasma.

• Partial Pressure: High in alveoli and arterial blood; low in tissues and venous blood.

• Types of Hypoxia: Anemic, ischemic, histotoxic, hypoxemic.

• Hemoglobin Affinity: Decreased by increased temperature, CO2, H+ (Bohr effect), and 2,3-BPG.

Carbon Dioxide Transport

• Transport Mechanisms: 70% as bicarbonate ion (HCO3-), 23% bound to hemoglobin, 7% dissolved in plasma.

• Partial Pressure: High in tissues and venous blood; low in alveoli and arterial blood.

• Imbalances: Excess CO2 leads to acidosis; too little leads to alkalosis.

Lung Diseases (General Descriptions)

• Obstructive Diseases: Increased airway resistance (e.g., asthma, chronic bronchitis).

• Restrictive Diseases: Reduced lung expansion (e.g., pulmonary fibrosis).

Blood

General Functions

• Transport of gases, nutrients, hormones, and wastes.

• Regulation of pH, temperature, and fluid volume.

• Protection against blood loss (clotting) and infection (immune cells).

Components of Blood

• Plasma: Liquid matrix; 90% water, contains proteins, nutrients, hormones, wastes.

• Formed Elements: Erythrocytes (RBCs), leukocytes (WBCs), platelets (thrombocytes).

Erythrocytes (Red Blood Cells)

• Function: Transport O2 and some CO2.

• Regulation: Erythropoiesis in red bone marrow; regulated by erythropoietin (EPO) from kidneys in response to hypoxia.

Leukocytes (White Blood Cells)

• Function: Defense against pathogens.

• Types: Neutrophils, lymphocytes, monocytes, eosinophils, basophils (each with specialized functions).

Platelets

• Function: Essential for blood clotting (hemostasis).

Hemostasis (Blood Clotting)

• Vascular Spasm: Vasoconstriction to reduce blood loss.

• Platelet Plug Formation: Platelets adhere to exposed collagen and aggregate.

• Coagulation: Fibrin mesh forms, stabilizing the clot.

Blood Grouping (Types)

• Agglutinogens: Antigens on RBC surface (determine blood type).

• Agglutinins: Antibodies in plasma against foreign agglutinogens.

• ABO Types: A, B, AB, O (based on presence/absence of A and B agglutinogens).

• Rh Factor: Presence (+) or absence (−) of D antigen; Rh− individuals can develop anti-Rh antibodies after exposure.

• Pregnancy: Rh incompatibility can cause hemolytic disease of the newborn if mother is Rh− and fetus is Rh+.

Blood Type	Agglutinogens (Antigens)	Agglutinins (Antibodies)	Can Receive From
A	A	Anti-B	A, O
B	B	Anti-A	B, O
AB	A, B	None	A, B, AB, O
O	None	Anti-A, Anti-B	O

The Heart

Pulmonary and Systemic Circuits

• Pulmonary Circuit: Right side of heart pumps deoxygenated blood to lungs for gas exchange.

• Systemic Circuit: Left side pumps oxygenated blood to body tissues.

General Structure of the Heart

• Coverings: Pericardium (fibrous and serous layers).

• Chambers: 2 atria (receiving), 2 ventricles (pumping).

• Valves: Atrioventricular (tricuspid, bicuspid/mitral), semilunar (pulmonary, aortic).

Pathway of Blood Through the Heart

• Right atrium → right ventricle → pulmonary trunk → lungs → left atrium → left ventricle → aorta → body.

Cardiac Muscle Fibers

• Characteristics: Striated, branched, interconnected by intercalated discs (gap junctions and desmosomes).

• Nutrition/Gas Supply: Coronary arteries supply oxygen and nutrients.

Electrical Events of the Heart

• Sequence of Excitation: SA node → AV node → AV bundle (bundle of His) → bundle branches → Purkinje fibers.

• Electrocardiogram (ECG): P wave (atrial depolarization), QRS complex (ventricular depolarization), T wave (ventricular repolarization).

Mechanical Events of the Heart (Cardiac Cycle)

• Phases: Atrial systole, ventricular systole, diastole.

• Heart Rate Regulation: Autonomic nervous system, hormones, ions, fitness, age.

Homeostatic Imbalances

• Myocardial Infarction: Heart attack due to blocked coronary artery.

• Fibrillation: Rapid, irregular heart contractions.

Blood Vessels

Tunics of Blood Vessels

• Tunica Intima: Endothelial lining.

• Tunica Media: Smooth muscle and elastic fibers (controls vasoconstriction/dilation).

• Tunica Externa: Connective tissue (protects and anchors vessel).

Types of Blood Vessels

• Arteries: Carry blood away from heart; thick walls.

• Capillaries: Exchange vessels; thin walls for diffusion.

• Veins: Carry blood toward heart; thinner walls, valves to prevent backflow.

Types of Arteries

• Elastic Arteries: Largest, near heart, withstand high pressure.

• Muscular Arteries: Distribute blood to organs.

• Arterioles: Smallest, control flow into capillaries.

Types of Capillaries

• Continuous: Most common; uninterrupted lining.

• Fenestrated: Have pores; found in kidneys, intestines.

• Sinusoidal: Large gaps; found in liver, bone marrow.

Capillary Exchange

• Substances move by diffusion, filtration, and osmosis.

• Driven by hydrostatic and osmotic pressures.

Veins

• Thinner walls, larger lumens, contain valves to prevent backflow.

Pulse and Blood Pressure

• Pulse: Rhythmic expansion of artery due to heartbeat.

• Blood Pressure: Force of blood against vessel walls; measured as systolic/diastolic (e.g., 120/80 mmHg).

• Influencing Factors: Cardiac output, blood volume, resistance, vessel elasticity.

*Additional info: Academic context and definitions have been expanded for clarity and completeness. Table for blood types has been included for reference.*