Circulatory and Respiratory Systems Flashcards
Heart
Right side pumps deoxygenated blood into pulmonary circulation. Left side pumps oxygenated blood into systemic circulation
Atria
Two upper chambers
Thin-walled
Ventricules
Two lower chambers
Extremely muscular
Blood flow through the heart
- Through the right atrium, tricuspid valve (3 cusps) into right ventricle
- Through pulmonary semilunar valve (3 cusps) into pulmonary arteries
- Return through pulmonary veins into left atrium
- Through mitral valve (2 cusps) into left ventricle
- Through aortic semilunar valve (3 cusps) into systemic circulation
Atrioventricular valves
Between the atria and ventricles
Prevent backflow into the atria
Systole
Period during which the ventricles contract, forcing blood out the heart into pulmonary and systemic circulation
Diastole
Period of cardiac muscle relaxation during which blood drains into all four chambers
Cardiac output
The total volume of blood the left ventricle pumps out per minute
CO = HR (beats/min) X stroke volume (volume/contraction)
Heart contraction
- SA node
- AV node
- Bundle of His (AV bundle)
- Purkinje fibers
Sinoatrial node (SA)
Pacemaker
Small mass of specialized tissue in the wall of the right atrium
Originates cardiac contraction and spreads impulses through the atrium, stimulating the to contract simultaneously
Atrioventricular node (AV)
Slowly conducts impulses to the rest of the heart allowing for atrial contraction and ventricles to fill with blood
Bundle of His (AV bundle)
Branches into the right and left bundle branches down the ventricles
Purkinje fibers
Up the walls of the ventricles
Stimulate strong contraction
Types of blood vessels
Arteries
Veins
Capillaries
Arteries
Thick-walled, muscular, elastiv vessels that transport oxygenated blood away from the heart
Veins
Thin-walled, inelastic vessels that transport deoxygenated blood toward the heart
Compression depends on skeletal muscle
Capillaries
Very thin walls composed of a single layer of endothelial cells across which respiratory gases, nutrients, enzymes, hormones, and wastes readily diffuse
Lymph vessesl
Transport excess interstitial fluid (lymph) to the cardiovascular system, keeping fluid levels constant
Lacteals
Smallest lymphatic vessels that collects fats (chylomicrons) from the villi in the small intestine and deliver them into the bloodstream
Lymph nodes
Swellings along lymph vessels containing phagocytic cells (lymphocytes) that filter lymph
Plasma
Liquid portion of the blood (55%)
Mixture of nutrients, salts, respiratory gases, wastes, hormones, and blood proteins
Leukocytes
White blood cells
Larger erythrocytes
Serve protective funcrtions
Platelets
Cell fragments that lack nuclei
Involved in clot formation
Erythrocytes
Red blood cells
Biconcave, disk-like shape gives increased surface area and greater flexibility
Contains ~250 million molecules of haemoglobin, each can bind 4 oxygen
Bone marrow
Site of erythrocyte formation stimulated by erythropoietin
Lose their nuclei, mitochondria, and membranous organelles to circulate for 120 days
Antigens
Macromolecules that are foreign to the host organism and trigger an immune response
Universal recipient
Type AB
Neither anti-A nor anti-B antibodies
Will not reject transfusions of any blood type
Universal donor
Type O
Does not posses any surface antigens that would elicit an immune response
Rh factor
Blood antigen that may be present on RBC surface
Rh+ possesses Rh antigen
Rh- lacks Rh antigen
Erythroblastosis fetalis
Severe anemia in a fetus if the anti-Rh antibodies of the mother cross the placenta and destroy fetal red blood cells
Clotting cascade
- Platelets come into contact with exposed collagen of damaged vessel. Release chemical causing neighbouring platelets to adhere forming a platelet plug
- Platelets release clotting factor thromboplastin
- Thromboplastin and its cofactors Ca2+ and vitamin K convert inactive prothrombin to active thrombin
- Thrombin converts fibrinogen into fibrin
- Threads of fibrin coat the damaged are and trap blood cells
- Fluid left after clotting is serum
Ventilation
Process by which air is inhaled and exhaled
Take in oxygen and eliminate carbon dioxide
Inhalation
Phrenic nerve innervates the diaphragm to contract and flatten
External intercostal muscles contract
Rib cage and chest wall push up an out
Increase thoracic cavity volume, reducing pressure, causing lungs to expand and fill with air
Exhalation
Diaphragm and external intercostal muscles relax
Chest wall pushes inward
Decrease thoracic cavity volume, increasing pressure, forcing air out and lungs deflate
Surfactant
Protein complex secreted by cells in the lungs to keep lungs from collapsing by decreasing surface tension in the alveoli
Ventilation control
Regulated by neurons in the medulla oblongata
Excessive CO2 and H+ in blood causes respiratory center to stimulate increased rate of ventilation
Pulmonary capillaries
Dense network of minute blood vessels that surround the alveoli
Total lung capcity
The maximum volume of air the lungs can hold
Tidal volume
The volume of air moved during a normal resting breath
Inspiratory reserve volume
The volume of air that could be additionally inhaled into the lungs at the end of a normal, resting inhalation
Expiratory reserve volume
The volume of air left in the lungs at the end of a normal, resting exhalation
Vital capacity
The volume of air moved during a maximum inhalation followed by a maximum exhalation
Residual volume
The air left in the lungs after maximum exhalation
