| Cardiovascular and Respiratory Anatomy and Physiology |
| Cardiovascular Anatomy and Physiology The Heart · Atrium (top) · Ventricle (bottom) · The right and left atria function principally as blood reservoirs, but also pump blood into the right and left ventricles. The right and left ventricles, respectively, supply the main force that propels the blood through the pulmonary and peripheral circulations. Valves · Artrioventricular (AV) valve o Triscuspid valve o Mitral valve o Prevent the flow of blood from the ventricles back into the artia during ventricular contraction (Systole) · Semilunar valve o Aortic valve o Pulmonary valve o Prevent backflow from the aorta and pulmonary arteries into the ventricles during ventricular relaxation (Diastole) Conduction System · Sinoatrial (SA) node rhythmic electrical impulses are initiated (internodal pathways) · Artrioventricular (AV) node impulse is delayed before passing into the ventricles · Artrioventricular (AV) bundle conduct impulse to the ventricles · Purkinje fiber conduct impulse to all parts of the ventricle Electrocardiogram · Electrocardiogram (ECG) o Depolarization QRS complex (ventricular contraction) o Repolarization T wave (ventricles recover from the state of depolarization) Blood Vessels · Artery o To transport blood pumped from the heart under high pressure to tissues o Arteiole act as control valves through which blood enters capillaries o Metarteriole conduits giving rise to capillaries and supplying the capillary bed or as thoroughfare channels bypassing the capillary bed, emptying into the venules · Capillary o To exchange oxygen, fluid, nutrients, electrolytes, hormones, and other substances between the blood and the interstitial fluid in the various tissues of the body. · Vein o Venule collect blood from the capillaries, gradually coalescing into progressively larger veins, which function as conduits for transporting blood from tissues back to the heart. Blood · Hemoglobin Iron-protein molecule carried by the red blood cells. (Transport oxygen) · Buffering power acid-base buffer (hemoglobin) |
| Respiratory Anatomy and Physiology · Trachea the first-generation respiratory passage · Bronchus - the second-generation respiratory passage · Bronchiole additional generations · Alveolus gases are exchanged in respiration Exchange of Air o The lungs are expanded and contracted in: o By downward and upward movement of diaphragm to lengthen and shorten chest cavity o By elevation & depression of ribs to increase & decrease anteroposterior diameter of chest cavity · Pleural pressure pressure in the narrow space between the lung pleura and chest wall pleura o Pleura membranes enveloping the lungs and lining the chest walls) · Alveolar pressure pressure inside the lung alveoli when the glottis is open and no air is flowing into or out of the lungs |
| Exchange of Respiratory Gases Control of Respiration - The nervous system adjusts the rate of alveolar ventilation by adjusting the rate and depth of breathing in order to meet the demands of the body. Thus, arterial blood oxygen concentration and carbon dioxide concentration are har4dly altered even during strenuous exercise Respiratory Center · Respiratory center o Dorsal respiratory group play the fundamental role in the control of respiration o Ventral respiratory group respiratory signals from the ventral respiratory group contribute to the respiratory drive for increased pulmonary ventilation, when increased ventilation becomes necessary. o Pneumotaxic center control both the rate and pattern of breathing Peripheral Chemoreceptor System · Peripheral chemoreceptor system Available for controlling respiration. o Peripheral chemoreceptors are located in several areas outside the brain and are especially important for detecting changes in oxygen concentration in the blood, although they also respond to changes in carbon dioxide and hydrogen ion concentration. |
| Cardiovascular and respiratory Responses to Acute Exercise |
| Cardiovascular responses Cardiac Output · Cardiac output the amount of blood pumped by the heart o Q = Stroke volume (SV) x Hear rate (HR) · Stroke volume quantity of blood ejected with each contraction · Heart rate the hearts rate of pumping Stroke Volume · End-diastolic volume volume of blood in left ventricle at the end of filling phase, or diastole · Starlings law of the heart force of contraction is a function of length of fibers f muscle wall · Ejection fraction fraction of blood ejected from the end-diastolic volume Heart Rate · Acetylcholine (hormone of the parasympathetic nervous system) is released from the vagal nervous endings, retarding the rate of SA node discharge and slowing the heart rate. · Bradycardia fewer than 60 beats/min · Tachycardia more than 100 beats/min Oxygen Uptake · Maximal oxygen uptake Greatest amount of oxygen that can be utilized at cellular level for entire body · Metabolic equivalent (MET) Resting oxygen uptake (3.5 ml O2/g of body weight/min) · Fick equation Q = VO2 / a-vO2 difference Blood Pressure · Rate-pressure product Work of heart is obtained by multiplying heart rate & systolic blood pressure · Mean arterial pressure average blood pressure throughout cardiac cycle · Normal resting pressure ranges from 110-140 mm Hg systolic/60-90 mm Hg diastolic Control of Local Circulation · Total peripheral resistance Resistance of the entire systemic circulation o Viscosity of blood o Length of vessel o Diameter of vessel · Viscosity resistance to flow (primarily result of friction drag of suspended red blood cells) · Adrenergic fiber Norepinephrine acts as general vasocontrictor & is released at certain sympatheic nerve endings. · Cholinergic fiber other sympathetic neurons (in skeleral and heart muscle) release acetylcholine · Vasomotor tone The degree of constrictor activity Internal Influences of Cardiorespiratory Responses Respiratory Responses · Minute ventilation volume of air breathed in 1 min · Tidal volume amount of air inhaled and exhaled with each breath · Ventrilatory equivalent ratio of minute ventilation to oxygen consumption · Anatomical dead space nondiffusible conducting portions of respiratory tract (nose, mouth, trachea) · Physiological dead space - portion of alveolar volume with poor ventilation-perfusion ratio Gas Responses Blood Transport of Gases and Metabolic By-Products |
| Cardiovascular and Respiratory Responses to Exercise Training The Heart Capillary Circulation Blood Ventilation Oxygen Extraction Lactic Acid |
| External Influences on Cardiorespiratory Response Altitude - Maintenance of acid-base balance of body fluids altered by hyperventilation - Increased formation of hemoglobin in red blood cells - Changes in local circulation and cellular tolerance to relative hypoxia of medium and high altitudes Hyperoxic Breathing Smoking Blood Doping |