Cardiorespiratory System Flashcards
Cardiorespiratory System
Primary purpose is to deliver adequate amounts of oxygen, remove wastes from body tissues, and to maintain carbon dioxide homeostasis in body tissues (15-25 times greater oxygen demand during exercise)
To meet oxygen demands of muscle during exercise the two major adjustments that must be made are:
1) Increased Cardiac Output
2) Redistribution of blood flow from inactive organs to active skeletal muscles
Circulatory System/Cardiovascular
Transports O2 and nutrients to tissues, removal of CO2 and waste from tissues, regulation of body temperature
Respiratory System
Adds oxygen and removes carbon dioxide from the blood; Plays an important role in the regulation of acid-base balance during heavy exercise
Heart
Creates pressure to pump blood
Arteries and Arterioles
Carry blood away from the heart
Capillaries
Exchange of O2, CO2, and nutrients between tissues; Oxygen is being used as final electron acceptor at the end of the electron transport chain, CO2 is byproduct of cellular metabolism and is used to make bicarbonate (major buffer of acidity), nutrients include glucose, amino acids, and lipids
Veins and Venules
Carry blood toward the heart
AVO2 Difference
Difference in oxygen tension between arteries and veins (How much oxygen is extracted from blood); 20-25% extracted during rest, 80-85% during work
Pulmonary Circuit
(Low Pressure Circuit) 25/5 mmHg; Right side of the heart, Pumps deoxygenated blood to the lungs via pulmonary arteries, Returns oxygenated blood to the right side of the heart via pulmonary veins
Systemic Circuit
(High Pressure Circuit) 120/80 mmHg; Left side of the heart, Pumps oxygenated blood to the whole body via arteries, Returns deoxygenated blood to the right side of the heart via veins
Which circuit (side of the heart) has less pressure?
Lower in Pulmonary Circuit (Right side of the heart) because it has Smaller blood volume, Shorter Vessels, Thinner walls, Less resistance to flow
Which side of the heart has thinner myocardial walls?
Right walls are thinner, left walls are thicker to send to entire systemic circuit
Pathway of Blood
Right Atrium> Tricuspid Valve> Right Ventricle> Pulmonary Semilunar Valve> Pulmonary Arteries> Lungs> Pulmonary Veins> Left Atrium> Mitral Valve> Left Ventricle> Aortic Semilunar Valve> Aorta> Arteries> Arterioles> Capillaries> Venules> Veins> Inferior and Superior Vena Cava> Back to RA
Epicardium/Visceral Pericardium
(fibrous and adipose tissue) serous membrane including blood capillaries, lymph capillaries, and nerve fibers (external); Lubricative pericardial sac/fluid prevents generation of friction and heat around heart
Myocardium
(muscle) Cardiac muscle tissue separated by connective tissues and including blood capillaries, lymph capillaries and nerve fibers
Muscular portion of heart wall that provides contractions that eject blood from heart chambers
Endocardium
Endothelial Wall) Endothelial tissue and a thick sub-endothelial layer of elastic and collagenous fibers (continuous with endothelial of the blood vessels); Serves as a protective inner lining of the chambers and valves
Myocardial thickness
The thicker the muscle or the more hypertrophy the muscle, the greater the pressure it can exert; thicker part should be associated to the part that has to push the furthest (systemic circuit)
Myocardial Hypertrophy=
Not Safe; occurs due to high resistance at aorta or peripheral arteries (scarred arteries)
Thickness of Myocardium
RA: 1-2mm, RV: 3-5mm, LA: 3-5mm, LV: 8-12mm
How myocardial perfusion needs met
The myocardium receives blood supply via the right and left coronary arteries which branch off the aorta and encircle the heart, when this blood flow is disrupted it can cause permanent damage to the heart; This injury results in the death of cardiac muscle cells and is known as a heart attack or myocardial infarction (The number of heart cells that die determines the severity of the heart attack)
Myocardial Infarction
Heart is protected by exercise training during it and myosin isoform changes
R & L Ventricle
Pressure Generation; Myocardium = Thickness Varies
Aorta & Large Arteries
Pressure Storage Increase Elastin (recoil)
Small Arteries & Arterioles
Resistance Vessels
Less Elastin, More Circular Smooth Muscle
Veins
Volume Storage
Little Elastin or Smooth Muscle, Thin Walls
