Circulation Overview Flashcards
(31 cards)
What is the function of the circulation system?
Functions to transfer materials between external environment and internal cellular spaces
Consists of cardiovascular and lymphatic systems
What is the cardiovascular system?
Heart and blood vessels (arteries, capillaries, veins)
What is the lymphatic system?
Collects fluid from tissue spaces and returns it to the venous circulation
What is the function of the pulmonary circulation?
Pumps low oxygen blood from right bentricle to lungs through pulmonary arteries
What is the function of the systemic circulation?
Pumps oxygen-rich blood from the left ventricle to the body through the aorta
Describe the pathway of blood starting with the RA.
RA –> RV –> Pulm. Arteries –> Lung capillaries –> Pulm. Veins –> LA –> LV –> Aorta +systemic arteries –> Systemic capillaries –> Systemic veins –> Vena Cavae –>
What are arteries?
Carry oxygen-rich blood under relatively high pressure from the heart to all parts of the body
What are Veins?
Return low-oxygen blood to heart, carry blood under lower pressure than arteries (except pulmonary veins)
What are capillaries?
Connect arterial and venous circulation for nutrient, oxygen, and waste exchange
What is the tunica adventitia?
Vessel outer connective tissue latyer
What is the tunica media?
Middle smooth muscle layer, most variable in thickness and amount of elastic fibers
Controls vessel constriction
What is the tunica intima?
Inner lining of endothelial cells supported by delicate connective tissue
What are Large, conducting arteries?
Receive initial cardiac output
Many layers of elastic fibers in TM to allow expansion and recoil during the cardiac cycle
Helps maintain constant flow of blood and minimizes changes in BP
E.g. aorta, pulmonary trunk
What are medium, distributing muscular arteries?
Composed primarily of smooth muscle in TM
Muscle wall allows vessels to decrease their diameter and regulate blood flow to different parts of the body
E.g. most of the named arteries
What are small arteries and arterioles?
Narrow lumina and thick muscular walls
Arteriole smooth muscles control the filling of capillary beds and regulate the arterial pressure in teh vascular system
These can result in hypertension if the muscle tonus is above normal
What is atherosclerosis?
Common form of arteriosclerosis associated with fat and cholesterol buildup - may result in thrombus
What are anastomoses?
Communications (connections) between branches of arteries
What are collateral vessels?
Series of smaller vessels that supply a tissue in addition to its main blood supply
What are end arteries?
Do not have functional anastomoses
Blockage interrupts tissue perfusion, usually results in tissue necrosis after occlusion
What are venules and small veins?
Smallest unnamed veins that drain capillaries
Venules join to form small veins, which empty into larger veins and unite to form venous plexuses
What is a medium vein?
Drain venous plexuses and accompany medium arteries
Have valves that permit blood flow towards the heart but prevent back flow
E.g. named superficial veins of upper and lower limbs
What are accompanying veins?
Occur as multiple vessels in a common vascular sheath with an artery
What are large veins?
Contain smooth muscle and a well-developed tunica adventitia
What are capillaries?
Continuous vessels that connect arterioles and venules
