Week 7: Chp 28: Overview of the Cardiovascular System Flashcards
Circulation
flow of blood throughout the heart and blood vessels
-flow of blood throughout the body and heart
Perfusion
blood flow to a capillary bed to provide nutrients and oxygen to tissues and organs
-blood flow to a capillary bed where nutrients and oxygenation is provided to tissues and organs (part of internal respiration)
Primary Function of The Cardiovascular System
- deliver oxygenated blood to the tissues and return deoxygenated blood back to the heart and lungs
- accomplished through the interaction of a muscular pump (heart) and a large complex of arteries and veins
Primary Job of the Heart
- propel blood from its left side into the aorta and the systemic circulation to provide oxygen and nutrients to the tissues
- muscle that pumps blood throughout the body
The amount of blood ejecting from the left heart is called?
cardiac output (CO)
Cardiac Output (CO)
- the amount of blood ejecting from the left heart
- varies depending on the bodys metabolic demands, increasing with exercise and decreasing when at rest
What happens after blood circulates in the body?
the blood returns to the right heart through the great veins, the superior and inferior vena cavae, to be delivered to the lungs to receive oxygen and remove carbon dioxide
The Vascular System Consists of
a combination of arteries, veins, and capillaries
-arterial and venous vascular systems
Arteries
carry oxygenated blood away from the heart
Veins
carry deoxygenated blood back to the heart
Which artery is an exception from oxygenated blood in the heart?
pulmonary artery
-carries deoxygenated blood away from the heart to get oxygenated by the lungs
The Function of the Vascular System
- the delivery of oxygenated blood to the tissues
- the removal and transportation of cellular waste for excretion
- the return of circulatory volume to the right heart
- the return of lymph fluid back into the general circulation
The Arterial System Consists of
high-pressured, thick walled muscular vessels
Function of the Arterial System
carry oxygenated blood from the heart to the tissues
- carries blood away from the heart
- accomplished through a series of vessels gradually decreasing in size, eventually entering the smallest vessels, the capillaries, where the actual oxygen and nutrient exchange takes place
- sequence of vessels: arteries to arterioles to metarterioles to capillaries
Sequence of vessels in the Arterial System
arteries –> arterioles –> metarterioles –> capillaries
The Venous System Consists of
low-pressure vascular circuit with vessels that contain valves to prevent retrograde, or backward, flow.
- these vessels carry blood from the capillary bed through venules, then veins, back to the heart
- Veins also have the flexibility to adapt to changes in volume without large changes in pressure; allows for the infusion of IV fluids and blood products
Sequence of Vessels in the Venous System
capillary bed —> venules —> veins–> back to heart
What have the flexibility to adapt to changes in volume without large changes in pressure
Veins
-this allows for the infusion of IV fluids and blood products
Where is the real work of the vascular system done?
at the capillary bed
What happens at the capillary bed?
oxygen and nutrients are delivered to the tissues and cellular waste is removed
-exchange
How Many capillaries are in the body?
- tremendously abundant in the body
- estimated in billions
- their abundance makes them close to virtually every cell in the body
Is the entire capillary system ever full at the same time?
- NO
- there are muscle cells or precapillary sphincters at the entrance of each capillary that constrict or dilate to deliver or divert blood to areas of need
- when precapillary sphincters are open, capillaries are filled with blood
- when a precapillary sphincter closes, the corresponding capillary shuts down, and blood travels through a thoroughfare channel, going directly from metarteriole to venule; in this way blood is diverted to organ systems in need
