Circulatory and Respiratory Systems Flashcards
cardiovascular system
composed of a muscular, four-chambered heart, a network of blood vessels and the blood itself
aorta
this is where blood is pumped
arteries
- branches from the aorta
- thick-walled muscular, elastic vessels that transport oxygenated blood away from the heart
arterioles
branches from the arteries
capillaries
- branches from the arteries
- have the smallest diameter of all three types of vessels
- red blood cells must often travel through them single file
venules
converged capillaries
veins
- converged venules, which carry deoxygenated blood back toward the heart
- relatively thin-walled, ineleastic vessels that conduct deoxygenated blood toward the heart
The Heart
- the driving force of the circulatory system
- the right side of the heart pumps deoxygenated blood into pulmonary circulation toward (toward the lungs)
- the left side pumps oxygenated blood into systemic circulation (throughout the body)
- the two upper chambers are called atria and the two lower chambers are called ventricles
atria
thin-walled
ventricles
- muscular
- the left ventricle is more muscular than the right ventricle b/c it is responsible for generating the force that propels the systematic circulation and because it pumps against higher resistance
Blood Flow
- blood returning from the body first flow through the right atrium, then through the tricuspid valve into the right ventricle, and finally through the pulmonary semilunar valve into the pulmonary arteries to continue to the lungs
- blood returning from the lungs flows through the pulmonary veins into the left atrium, then through the mitral valve into left ventricle and finally out through the aortic semilunar valve into the systemic circulation
Atrioventricular Valves
prevent backflow of blood into the atria
Tricuspid Valve
the valve on the right side of the heart and has three cusps
Mitral Valve
the valve on the left side of the heart and two ups
Semilunar Valves
have three cups and are located between the left ventricle and the aorta and between the right ventricle and the pulmonary artery
Contraction
the heart’s pumping cycle is divided into alternating phases, systole and diastole, which make up the heart beat
Systole
the period during which the ventricles contract, forcing blood out of the heart into pulmonary systematic circulation
Diastole
the period of cardiac muscle relaxation during which blood drains into all four chambers
Cardiac Output (heart rate)
the total volume of blood the left ventricles pumps out per minute
Sinoatrial (SA) node
an ordinary cardiac contraction originate in and is regulated by the SA node (the pacemaker), a small mass of specialized tissue located in the wall of the right atrium
Atrioventricular (AV) node
the impulse arrives at the AV node, which slowly conducts impulses to the rest of the heart, allowing enough time for atrial contraction and for ventricles to fill with blood
Bundle of His (AV bundle)
the impulse is then carried by the AV bundle which branches into the left and right bundle branches, and finally through the Purkinje fibers in the walls of both ventricles
Autonomic Nervous System
modifies the rate of heart contraction
Parasympathetic Nervous System
innervates the heart via the vagus nerve and causes a decrease in heart rate
Pulmonary Arteries
transport deoxygenated blood from the heart to the lungs
Pulmonary Veins
carry oxygenated blood from the lungs to the heart
Lymph Vessels
-transports excess interstitial fluid, called lymph to the cardiovascular system, thereby keeping fluid levels in the body constant
Lacteals
collect fats from the villi in the small intestine and deliver them into the blood stream, bypassing the liver
Lymph nodes
swellings along lymph vessels containing phagocytic cells (lymphocytes)that filter the lymph, removing and destroying foreign particles and pathogens
Blood
has both liquid components and cellular components
Plasma
the liquid portion of blood, an aqueous mixture of nutrients, salts, respiratory gases, wastes, hormones, and blood proteins
-the cellular components of blood are erythrocytes, leukocytes, and platelets
Leukocytes
WBCs are larger than erythrocytes and serve protective functions
Platelets
cell fragments that lack nuclei and are involved in clot formation
Erythrocytes
- AKA RBCs are thin oxygen-carrying components of blood
- contains approx 250 million molecules of hemoglobin when hemoglobin binds oxygen it is called oxyhemoglobin
- formed from stem cells in the bone marrow
- erythrocytes lose their nuclei, mitochondria, and membranous organelles in the bone marrow once mature, erythrocytes circulate in the blood for 120 days after which they are phagocytized in the spleen and liver
- finding immature erythrocytes circulating in the blood stream could mean a number of disease states
Functions of the Circulatory System
- blood transports nutrients and O2 to tissue and wastes and CO2 from tissue
- erythrocytes transport O2 throughout the circulatory system
- hemoglobin in erythrocytes bind to O2
- amino acids and simple sugars are absorbed into the blood stream at the intestinal capillaries
- metabolic waste products diffuse into capillaries from surrounding cells and delivered to the appropriate excretory organs
Hemoglobin
contains iron and capable of binding to four molecules of O2, can also bind to Co2
Clotting Cascade
- when platelets come into contact with exposed collagen of a damaged vessel, they release a chemical to neighboring platelets to adhere to another (platelet plug)
- the platelets and the damaged tissue release the clotting factor thromboplastin (co-factor calcium and vitamin K)
- threads of fibrin coat the damaged area and trap blood cells to form a clot
- fluid left after blood clotting is serum
- warfarin, anticoagulant, inhibits the recycling of vitamin K, pts are less likely to form clots
The Respiratory System
- air passages consist of the nose, pharynx, larynx, trachea, branchi, and branchioles, and alveoli
- gas exchange occurs in the thin walls of the alveoli
- ventilation is regulated by neurons located in the medulla oblongata
- when partial pressure in CO2 rises, the medulla oblangata increases the rate of ventilation
- total lung capacity represents the maximum volume of air the lungs can hold
