Ch 9 Part 1 Flashcards
Goals of the circulatory system
Distribute nutrients from digestive tract, liver, and adipose.
Transport O2 and CO2.
Transport metabolic waste to excretory system (kidneys).
Transport hormones.
Homeostasis of body temperature.
Hemostasis - blood clotting.
Perfusion, Ischemia, hypoxia
Perfusion: flow of blood through tissue.
Ischemia: inadequate blood flow.
Hypoxia: Adequate circulation, but inadequate O2
Components of Circulatory System
Heart - Arteries (high pressure) - arterioles - capillaries (single cells form wall, allows for diffusion of material) - venules - veins (low pressure)
Endothelial Cells
Blood vessels all have a thin layer of endothelial cells (this is the only layer for capillaries)
Endothelial cells contribute to:
Vaso-constric/dillation
Inflammation
Angiogenesis (creation of new blood vessels)
Thrombosis - blood clotting: undamaged endothelial cells secrete anti-clotting substances to prevent coagulation cascade.
Right V Left Heart
Right - pumps blood to lungs
Left - pumps to body
Pulmonary circulation
Heart - Lungs - Heart
Systemic Circulation
Heart - rest of body - Heart
Division of Pulmonary and Systemic Circulation
Avoids having to pump blood through two capillary beds which would require significant pressure.
Exceptions = Portal System.
Portal Systems
Hepatic portal system: Blood moves through capillaries in intestine, travels in veins to liver, blood passes through capillary bed in liver.
Hypothalamic-hypophysial system: Blood passes through capillaries in hypothalamus - moves through portal viens - then to capillaries in pituitary.
Benefit is direct transport from one system to another without having to move through entire body. ie.
Nutrients –> Liver
Hormones –> Pituitary
Atria
Reserves, “waiting rooms” - blood can collect from veins before being pumped to ventricles.
Right Atrium
Receives deoxygenated blood from systemic circulation.
From inferior vena cava and superior vena cava.
Pumps to right ventricle.
Left Atrium
Receives Oxygenated blood from the lungs via Pulmonary veins.
transfers to left ventricle which pumps oxygenated blood to rest to systemic circulation via aorta.
Coronary Arteries
First branches from Aorta feed back to the heart to oxygenate the muscles.
Coronary Veins
Deoxygenated blood from heart is brought back to the right atrium via the coronary sinus.
Note, this is the only blood that does not return to the heart via the inferior of superior vena cava.
Atrioventricular Valve
Required to divide atria and ventricle and prevent backflow.
AV Valve between left atrium and left ventricle is bicuspid or mitral valve.
If bicuspid breaks, result is blood flowing through aorta and back to left atrium. Consequence is elevated pulmonary blood pressure and pulmonary edema.
Tricuspid valve is between right atria and ventricle.
Pulmonary and Aortic semilunar valves
Are between large arteries and ventricles.
Varicose Veins
result of valve failure in veins that normally prevent backflow.
Pregnant women often suffer from varicose veins.
Cardiac Cycle
Happens at the same time on both sides.
Two periods: Diastole and Systole.
Diastole: Ventricles are relaxed, blood flows from atria to ventricles. Atria contract.
Systeole: Ventricles contract; AV valves close; pressure builds; semilunar valves open and blood moves to aorta and pulmonary artery.
Begins at Lub (Closure of AV valve), ends at Dup sound (Closure of semilunar valves).
2/3 of blood are ejected during systole, ejection fraction.