Cardiac Function and Blood Flow vs

Cardiac Function and Blood Flow Summary

• Isovolumic contraction and relaxation occur when all heart valves are closed
• End diastolic volume (EDV) is the blood volume after ventricular diastole
• Atrial and ventricular valves open and close during different phases of the cardiac cycle
• Stroke volume is the amount of blood ejected from the ventricle in one heartbeat, calculated as EDV - ESV
• Cardiac output is the amount of blood ejected per minute, calculated as stroke volume times heart rate
• Autonomic nervous system control of heart rate involves parasympathetic and sympathetic influences
• Factors influencing stroke volume include contractility, venous return, and the Frank-Starling law of the heart
• Inotropic effects can be positive or negative and influence contractility, affecting stroke volume
• Venous return to the heart is influenced by the skeletal muscle pump, respiratory pump, and sympathetic nervous system
• Blood vessels include arteries, arterioles, metarterioles, capillaries, venules, and veins, each with distinct structures and functions
• Blood pressure is influenced by factors such as resistance, systolic and diastolic pressure, pulse, and mean arterial pressure (MAP)
• Factors influencing MAP include cardiac output, peripheral resistance, changes in blood volume, and compensation mechanisms

Respiratory System Physiology and Gas Exchange

• Iron is ingested from the diet and absorbed by active transport, with transferrin protein transporting iron in plasma to either the liver for storage as ferritin or to the bone marrow to form hemoglobin inside red blood cells.
• Hemostasis involves vasoconstriction, forming a platelet plug, and then forming a clot.
• The primary functions of the respiratory system are gas exchange, regulation of body pH, protection from inhaled pathogens and irritating substances, and vocalization.
• The pleural sac is a double-layered membrane around the lungs that prevents friction, maintains lung inflation, and stores pleural fluid.
• Cells of the alveolar sacs include type 1 (for respiration/gas exchange), type 2 (secreting surfactant), and alveolar macrophages (for immunity).
• The pulmonary circulation pathway involves the right ventricle, pulmonary trunk, arteries, capillaries, venules, veins, and left atrium.
• The mucociliary escalator traps and removes pathogens using mucous, saline, and cilia, with the cells secreting saline and utilizing a paracellular pathway for movement.
• Dalton’s law states that the sum of partial pressures in a container equals the total gas pressure, while partial pressure is the pressure exerted by each gas in a mixture.
• Gas particles move down a concentration gradient, following Boyle’s law which states that changing the volume of a container changes the pressure inside.
• Lung volumes and capacities include tidal volume, inspiratory reserve volume, expiratory reserve volume, residual volume, inspiratory capacity, functional residual capacity, vital capacity, and total lung capacity.
• Pressure changes in the lungs during quiet breathing involve intrapleural pressure decreasing during inhalation and increasing during exhalation, while alveolar pressure decreases during inhalation and increases during exhalation.
• Surfactant is a detergent that prevents alveolar walls from collapsing by breaking down water polar molecules in alveoli. Airway resistance is affected by factors like radius, air flow, bronchodilation, and bronchoconstriction. Total pulmonary ventilation and alveolar ventilation are measures of air entering the airways and fresh air reaching the alveoli, respectively.
• Hypoxia is a decrease in oxygen levels, while hypercapnia is an increase in carbon dioxide levels. Sensors respond to oxygen levels, carbon dioxide levels, and pH to avoid hypoxia and hypercapnia. Gas diffusion rate is affected by surface area, concentration gradient, barrier permeability, and diffusion distance. Oxygen is transported in blood and its binding to hemoglobin is determined by partial pressure and affinity.