Chapter 3 The Cardiorespiratory System:
- Figure 3.3 Atria and Ventricles know the functions of the right and left atrium and the right and left ventricles
- Table 3.1 Support Mechanisms of Blood
- Table 3.2 Structures of the respiratory pump.
The Cardiovascular System
- Cardiorespiratory system – composed of cardiovascular and respiratory system.
- Cardiovascular system – Heart, blood, and blood vessels.
- Heart – Hollow, muscular organ that pumps a circulation of blood through the body by means of rhytmic contraction. Positioned in thoracic cavity, lying anteriorly(in front) to the spine and posteriorly(behind) the sternum.
- Mediastinum – Space in the chest between lungs that contains all internal organs of the chest except lungs. Adult heart size of fist weighs 300g.
- Cardiac muscle one of three major types, involuntary muscle, not consciously controlled.
- Cardiac muscles are shorter and more tightly connected than skeletal muscle. Have irregularly spaced dark bands called intercalated discs.
- Sinoatrial (SA) Node – Specialized area of cardiac tissue located in the right atrium of the heart which initiates electrical impulses that determine the pacemaker for the heart. Electrical signals are transmitted from the SA, through both atria and down into ventricles. Referred to as the pacemaker for the heart.
- Atrioventicular (AV) Node – Small mass of specialized cardiac muscle fibers, located in the wall of the right atrium of the heart, that receives heartbeat impulses from the sinoatrical node and directs them to the walls of the ventricles. AV node delays electrical impulse from SA before allowing it to move on to ventricles. Directs impulses to walls of ventricles.
- Heart composed of four hollow chambers, delineated into two interdependent but separate pumps on each side. Two pumps are separated by interatrial septum(separates atria) and interventicular septum(separates the venticles).
- Each side of the heart has two chambers, an atrium and a ventricle.
- Right side of the heart is the pulmonic side because it receives blood from the body that is low in O2 and high in CO2 and pumps it to the lungs then back to the left atria.
- Left side of heart is systemic side, pumps blood high in O2 low in CO2 to rest of the body.
- Blood pumped from right side, pulmonic, to the lungs, then through left side, systemic to the rest of the body. Right to left.
- Atria – Superior(upper) chamber of the heart that receives blood from veins and forces it into ventricles. On either side of heart. Gather blood returning to heart. Right atrium gathers deoxygenated blood, left atrium gathers oxygenated blood from lungs.
- Ventricles – Inferior(lower) chamber of the heart receives blood from its corresponding atrium and forces blood into arteries. Larger than atria. Right ventricle has thin walls and pumps under low pressure. Left ventricle has thicker walls and pumps under high pressure b/c it pumps blood out to the rest of the body. Right ventricle receives deoxygenated blood from right atrium, left ventricle receives oxygenated blood from left atrium.
- Each chamber of heart is separated from one another and major veins and arteries by valves to prevent backflow or spillage of blood.
Functions of the Heart
- Stroke Volume – Amount of blood pumped out of the heart with each contraction. Difference between ventricular end-diastolic volume(EDV) and end-systolic volume(ESV). EDV is filled volume of ventricle before contraction, ESV is residual volume of blood remaining in ventricle after contraction. Typical EDV 120mL and ESV 50mL. Difference, 70mL represents SV. D comes before S EDV is BEFORE contraction, and ESV come AFTER contraction.
- Heart Rate – Rate at which heart pumps.
- Cardiac output (Q) – Heart rate x stroke volume, overall performance of heart.
- Blood – Fluid circulates in the heart, arteries, capillaries, and veins, carries nutrients and oxygen to all parts of the body and also rids body of waste products. Blood consists of cells suspended in watery luiquid called plasma, which also contains nutrients such as glucose, hormoens, and clotting agents.
- Red, white, and platelets in blood cells.
- Plasma makes up 55% of volume of blood and 45% are red, white, platelets. 4-6L of blood in adult.
- Blood vessels – network of hollow tubes that circulates blood throughout body. Transported to and from heart.
- Arteries – Blood vessels that transport blood away from heart.
- Capillaries – Smallest blood vessels, site of exchange of chemicals and water between blood and tissue.
- Veins – Vessels that transport blood from capillaries toward the heart.
- Largest artery in the body is the aorta, carries blood away from the heart.
- Arterioles – small terminal branches of an artery which end in capillaries.
- Venules – Very small veins that connect capillaries to the larger veins.
The Respiratory System
- Respiratory System – Lungs and respiratory passageways that collect oxygen from external environment and transports it to bloodstream.
- Breathing is the process of moving air in and out of the body and requires optimal functioning of the respiratory pump and all its components.
- Respiratory Pump – Bones and soft tissue that work together to allow proper respiratory mechanics to occur and help pump blood back to heart during inspiration.
- Inspiration – Inhilation, actively contracting the inspiratory muscles to move air into body. Actively contracting.
- Expiration – Exhalation, process of actively or passively releasing inspiratory muscles to move air out of the body.
- Respiratory passages are divided into conducting airways and respiratory airways.
- Conducting airways consists of all structures that air travels through before entering respiratory airways. Nasal, oral cavaties, mouth, pharynx, larynx, trachea, basically your nose and throat before lungs.
- Diffusion – process of getting oxygen from environment to tissues of the body.
Cardiorespiratory System Function
- Cardiovascular and respiratory systems work together to transport oxygen to body tissues. Capacity to efficiently use oxygen is dependent on respiratory system’s ability to collect oxygen and the cardiovascular system’s ability to absorb and transport it.
- Use of oxygen by the body is oxygen uptake.
- Resting oxygen consumption (VO2) is approximately 3.5 mL of oxygen per KG of bodyweight per minute, typically named 1 metabolic equivalent or 1 MET.
- Fick equation – equation for oxygen consumption.
- Maximal Oxygen Consumption (VO2max) – Highest rate of oxygen transport and utilization achieved at maximal physical exertion. Best measure of cardiorespiratory fitness. Anywhere from 11 to 23 METs.
Abnormal Breathing Patterns
- Breathing pattern becomes more shallow, uses secondary respiratory muscles more than diaphram. Upper chest breathing becomes habitual causing overuse in secondary respiratory muscles such as scalenes, sternocleidomastoid, levator scapulae, and upper trapezius.
- Respiratory muscles also play major postual role in human movement system, all connecting directly to cervical and cranial portions of the body. Increased activity and excessive tension may result in headaches, lightheadedness, and dizziness.
- Excessive breathing(short, shallow) can lead to altered CO2 and Oxygen blood content and can lead to feelings of anxiety.
- Inadequate oxygen and retention of metabolic waste within muscles can create fatigued, stiff muscles.
- Inadequate joint motion of the spine and rib cage, as a result of improper breathing, causes joints to become restricted and stiff.