Cardiovascular Flashcards
What is the purpose of cardiac function?
Transport food and Oxygen to tissues, remove CO2 and waste
What is Pulmonary or central circulation?
Blood in the heart and pulmonary circulation linked to gas exchange
What is Systemic or peripheral circulation?
Blood not in the central circulation which perfuse tissues of the body
What is involved in the pulmonary circuit?
lungs and veins and arteries going to and from the heart
What is involved in the systemic circuit?
all other areas of the body including the heart
What areas of the body have 4% total blood volume each?
left ventricle and capilliaries, right ventricle & pulmonary arteries combined
What area of the body has 64% of the total blood volume?
veins
What areas of the body make up 16% of the total blood volume?
aorta, large arteries, small arteries, and artieroles
What does the fluid flow through a vessel depend on?
The pressure difference between the ends of the vessel and the vessel’s resistance to fluid flow
What does the pressure difference between the ends of the vessel do?
The pressure pushes fluid through and keeps the vessel from collapsing
What does the vessel’s resistance to fluid flow do?
The smaller vessels will have more resistance and the thicker fluids will have greater resistance
What does the blood flow through a vessel depend on?
The heart creating pressure at different ends of the vessel and the vessel’s resistance to blood flow
How does the heart create difference between pressures at the end of the vessels?
The heart pushes the blood through and the blood pressure keeps the vessels open
What increases the vessel’s resistance to blood flow?
Constricting artieroles and increased hematocrit`
Where is the velocity of blood flow the greatest?
In the middle of the vessel of and where it is smaller
What is laminar flow?
blood flows without disturbances parallel
What is turbulent flow?
Blood flow is disturbed
What is happening during the P wave?
depolarization of the atria
What is happening in the during the p interval?
delay in av node
What is happening during QRS?
depolarization of the ventricle
What is happing during the t wave?
repolarization of the ventricles
What is happening during diastole?
Your ventricles are relaxed while the blood flows into the atria then to the ventricles. The av valves are open and the sl valves are closed
What is happening during systole?
The ventricles are contracting and blood shoots out. The av valves are closed at the very beginning and sl valves open up to eject blood
What is cardiac output (CO)?
the amount of blood the heart pumps per minute (CO=SV x HR)
What is stroke volume (SV)?
Amount of blood the fills the left ventricle during diastole
What is ejection fraction?
the volume of blood ejected from the left ventricle during systole (~60%)
What is preload?
the work (and stretch) on the heart before contraction begins. Is determined by volume of venous return. The more blood that returns will induce a stronger contraction (Starling’s Law).
What is afterload?
the work on the heart after contraction begins. Is determined by systemic & pulmonic arterial blood pressure and narrowing of the aortic valve.
What is cardiac contractility?
ability of the heart to change the force of contraction, mainly controlled by inotropic mechanisms and Ca+
What collateral circulation?
perfusion of an area by more than one artery. Develops when an artery is occluded to the affected area.
What is blood pressure?
Blood Pressure = Cardiac Output x Peripheral Vascular Resistance
What is the difference between an artery and a vein structure?
arteries have 2 layers of tunica intima
What is the wall of a vein like?
thin walled and distensible (flexible)
How much of the blood is stored in the veins?
2/3
What prevents backflow of blood in the veins?
valves
What can cause clots in veins?
turbulent blood flow can cause clots near valves
What are the walls of capilaries like?
they are single celled thickness with pores and cell junctions. Soluble lipids diffuse through membranes and water moves through pores
What is the structure of an artery?
3 layers
- tunica intima
- tunica media
- tunica externa
What makes up the tunica intima?
Endothelium and connective tissue
What makes up the tunica media?
smooth muscle
What makes up the tunica externa?
collagen and elastic fibers
What is vascular endothelium?
When food and oxygen pass into tissues and when wastes and co2 pass from tissues into the blood
What is created by vascular endothelium?
- Creates compounds that cause vasodilation or vasoconstriction
- Creates growth factors that can stimulate smooth muscle
- Forms a smooth lining of the blood vessels that resists clot formation
- Creates compounds to promote clot formation in injured areas
How is blood pressure controlled normally?
through baroreceptors that stimulate the peripheral vascular resistance and the kidney that maintains blood volume with the heart
How is the long term control of blood pressure?
the lungs
What are the levels of prehypertension?
systolic = 120-139 Diastolic = 80-89
What are the levels of stage 1 hypertension?
systolic = 140-159 diastolic = 90-99
What are the levels of stage 2 hypertension?
systolic = greater than 160 diastolic = greater than 100
What is mean arterial pressure (MAP)?
Average pressure in the arteries during a single cardiac cycle
What are the normal ranges of MAP?
70-110 mmHg
What is MAP an indicator of?
tissue perfusion
What does your MAP have to be to stay alive?
65
How do you calculate MAP?
MAP = SBP (systolic) + 2 (DBP-diastolic)
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