Chapter 3/ The Cardirespiratory System Flashcards
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 rhythmic contraction. Positioned in thoracic cavity, lying anteriorly (in front) to the spine and posteriorly (behind) the sternum.
Mediastinum
Space in chest between lungs that contains all internal organs of the chest except lungs. Adult heart size of fist weighs 300g
3major types of muscle
Cardiac muscle, skeletal muscle, and smooth muscle.
Cardiac muscle
One of the three major types of muscle, involuntary muscle, not consciously controlled. Cardiac muscle fibers 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.
Atrioventricular (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 sinoatrial node and directs them to the walls of the ventricles. AV node delays electrical impulses from SA before allowing it to move in to ventricles. Directs impulses to walls of ventricles.
The 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 interventricular septum(separates the ventricles).
- 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 and low in CO2 to the rest of the body.
- Blood pumps from right side, pulmonic, to the lungs, then through left side, systemic to the rest of the body. Right to Left.
Atrium
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 forced 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 bc it pumps blood out of the rest of the body. Right ventricle receives deoxygenated blood from right atrium, left ventricle receives oxygenates blood from left atrium.
Stroke volume
Amount of blood pumped out of the heart with each contraction.
• end-diastolic volume (EDV) is filled volume of ventricle before a contraction.
• end-systolic volume (ESV) is residual volume of blood remaining in ventricle after contraction.
Typical EDV is 120ML and ESV is 50ML, the difference is 70ML which represents stroke volume.
• D comes before S. So, EDV is before contraction, ESV comes after contraction.
Heart rate
Rate at which heart pumps
Cardiac output (Q)
Heart rate x stroke volume, the overall performance of the 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 liquid called plasma, which also contains nutrients such as glucose, hormones, 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.
