Heart Part 3 Flashcards
Flow rate definition
Volume of blood passing through per unit of time
Blood pressure definition
Force exerted by blood against vessel
Pressure gradient definition
Difference in pressure between beginning and end of vessel
Resistance definition
Friction between blood and vascular wall
Flow rate factors
Proportional to pressure gradient
Inversely proportional to resistance
Factors of blood pressure
Dependent on
(1) distensibility of vessel walls
(2) volume of blood within vessel
Systolic pressure
Max pressure when blood ejected into arteries
Diastolic pressure
Minimum pressure when blood draining into rest of vessel during diastole
What is Mean Arterial Pressure
Main driving force of blood flow
Average pressure driving blood forward
Pressure that is monitored and regulated by body’s blood pressure reflexes (homeostasis)
How is Mean Arterial Pressure calculated
Diastolic pressure + 1/3 pulse pressure
OR
2/3 Diastolic pressure + 1/3 systolic pressure
How is blood reconditioned
Reconditioned organs receive more blood than necessary to perform homeostatic adjustments to blood
- digestive tract: collect nutrient
- kidneys: remove waste and adjust water and electrolytes
What is the function of arteries
Pressure reservoir and rapid transit passageways to organs
How is pulse pressure calculated
Systolic pressure - diastolic pressure
Where can pulse waves be felt
Over major arteries
How is pulse wave generated
Differences in systolic and diastolic pressure
Stronger difference = stronger pulse wave
What properties of arteries create Pulse Pressure
Elastic properties of arteries help convert pulsatile flow of heart into more continuous flow in capillaries
Why are capillaries designed as site of exchange
Thin walled
Extensive branching
Close proximity to cells for exchange
How are RBCs positioned in capillaries
RBCs in single file
Is the blood flow in capillaries faster than arteries?
No. Blood velocity is slower in capillaries than in arteries
How are exchangeable proteins move across capillaries
Via vesicular transport
How are small water soluble substances pass through capillaries
Via water-filled pores
How are lipid substances pass through capillaries
Passes through endothelial cells
Can plasma proteins pass through capillary walls
No
What is the flow rate like in capillaries
Same throughout capillary tree due to increased surface area (5L/min)
If muscle are more metabolic active, does that mean more capillaries are present?
Yes
What is the purpose of pre-capillary sphincters
Control blood flow in capillaries since most are not open under resting conditions and lacks smooth muscle
What happens when there is an increase in metabolic activity for capillaries
Increased metabolic activity = sphincters relax = more open capillaries = increased blood flow to active tissues
Factors that induce vasoconstriction
increased O2, endothelin, sympathetic stimulus (cold, vasopressin, angiotensin II)
decreased CO2
Factors that induce vasodilation
Increased nitric oxide, co2
decreased o2, sympathetic stimulus (heat, histamine release)
What are local vasoregulators of arterioles
Vasoconstriction, vasodilation, vascular tone
What is Vascular tone
State of partial constriction of arteriolar smooth muscle
Establishes baseline of arteriolar resistance
What are the factors that causes difference in flow to organs
Difference in vascularization
Difference in resistance by arterioles supplying organs
Effects of exercise
Increase in HR, Venous return, Stroke volume, Cardiac output, blood flow to active skeletal and heart muscles, MAP, Blood flow to skin
Decrease in TPR, Bloodflow to digestive tract, kidneys and other organs
No effect on bloodflow to brain
What are vasopressin and angiotensin II
Potent vasoconstrictors
What is the effect of vasopressin
maintains water balance
What is the effect of angiotensin II
Regulates salt balance
What hormones are adrenal hormones
Epinephrine and Norepinephrine
Effect of epinephrine
Reinforce vasodilatory mechanisms of skeletal and heart muscles
Effect of norepinephrine
Induces generalised vasoconstriction
Factors of BP
CO and TPR
What drains blood into right atrium
Coronary sinus
What is the appendage of atrium
Auricle
What part of the heart is found at the 4th/5th intercostal space along the midclavicular line
Apex of the heart
What is the branch that delivers blood from arch of aorta to right side of the body
Brachiocephalic artery
Left Anterior Descending (LAD) artery is also known as?
Anterior interventricular artery
What is the posterolateral recess of the pleural cavity where fluid accumulation could occur
Costophrenic/Costodiaphragmatic recess
Untreated blockage of coronary arteries lead to?
Ischemia of the cardiac tissue
What is the outermost layer of the heart
Epicardium
How to differentiate middle mediastinum from the anterior and posterior
If it is inside the fibrous pericardium, it is middle mediastinum.
What is the things associated with anterior and posterior mediastinum
Anterior mediastinum
- phrenic nerves
- thymus
Posterior mediastinum
- Descending aorta
- Esophagus
What is the muscle unique to right atrium
Pectinati muscles (Musculi pectinati)
what do veins function as
Blood reservoir
