CVS Flashcards
Functions of cvs?
Circulates, transports nutrients and oxygen, hormones and blood cells around the body.
Fights disease, stabilize temp, Ph & helps maintain homeostasis
What are the 3 essential components of the human cvs system?
Heart, blood and blood vessels
What is meant by having a “closed circulation?”
Blood never leaves the network of arteries, veins and capillaries
How much blood does an avergae human have? How much is rbc? Plasma?
5L
Rbc» 2L
Plasma» 3L
Where does most of our blood lie?
Peripheral veins (65%)
Where does the least of our blood lie?
In capillaries, but they have the bigest surface area which is needed for substance exchange!
How lomg can a patient live with a artificial heart inserted?
4 yrs approx
The heart has 2 major arteries…what r they?
Left and right coronory system
Define an “end artery” & give examples
A terminal artery supplying all or most of the blood to a body part without collateral circulation.
What are 2 types of end arteries?
Give examples for each
1) Absolute (true) end artery: there are no anastomoses, IN THE RETINA
2) Functional end arteries: have anastomoses
Ex coronory arteries, splenic artery, cerebral artery, renal artery
During a stenosis, what special action do arteries have to compensate this?
They form a collateral circulation, but it takes ages tho.
What is a collateral circulation?
the alternate circulation around a blocked artery or vein via nearby minor vessels. branches formed between adjacent blood vessels.
The left and right coronory artery arise from what?
The aorta
What is an example lf a natural collateral circulation in the body?
When the radial and ulnar arteries take the job of the brachial artery if damaged
List the component sof the electrical conducting system of the heart in order
Sa node Av node Bundle of his Left and r bundle branch Purkunjee fibers
Why is the AV node implise delayed for 0.1 sec?
To allow the atria to respond and complete it’s contraction so the ventricles cam contract
Why does the SA node set the pace for the whole heart?
Bc its the only conduction sys that has the faster depolarization rate
Ventricular fibrillation
heart rhythm problem that occurs when the heart beats with rapid, erratic electrical impulses. This causes pumping chambers in your heart (the ventricles) to helplessly shimmer instead of pumping blood.
Must give shock via paddles
What is sytole? Diastole?
Systole: LV contracts, causing a rise in aortic bp (120mm HG)
Diastole (relaxation): AV valves close & walls of aorta recoil causing a drop
What r the 3 walls of veins and arteries?
Tunica intima
Tunica media
Tunica adventitia
Why do veins have a thin wall in comparisin to arteries?
Bc they work in a low pressure system
What is an aneursym?
Dilation of a bv
Why are most abdominal aortic aneurysm in the infra renal region?
Due to an anatomical point, the junction of the suprarenal and infrarenal point has less elastin, thus is our weakest point
What is paroxysmal noctural dyspnoea?
Paroxysmal nocturnal dyspnea (PND) is a sensation of shortness of breath that awakens the patient, often after 1 or 2 hours of sleep, and is usually relieved in the upright position.
What is orthopnea
Orthopnea or orthopnoea is shortness of breath (dyspnea) that occurs when lying flat, causing the person to have to sleep propped up in bed or sitting in a chair
What happens to BNP during heart failure?
It is released from the distended left ventricle which acts to lower bv and blood pressure
What is muscle atrohpy? What could cause it?
Reduction in cell number or cell size
Muscle inactivity Malnutrition Cancer COPD Neurogenic disorders
What r some indicators of muscle injury/ necrosis?
Troponin I (cardiac) Myoglobinurea (skeletal muscle) Creatinine Kinase (all muscle)
When do levels of CK rise?
During increased muscle activity
Why does a”Dead leg” need to be amputated asap!
The dying cells will release pottasium which may travel to the heart and stop the activity
What r vaso vorum?
“Vessels of vessels”
is a network of small blood vessels that supply the walls of large blood vessels
What is located in the outer tunica adventitia?
Vaso vorum
Unmyelinated nerve endings, vasoconstriciton is stimulated by sympathetic nerve fibers.
When is an artery considered to be an arteriole?
When the diameter less than 0.1mm
How does the smooth muscle in the tunica intima of the artery differ from arteriole
In the artery» 40 layers of SM
in arteriole» 1-3 layers only
What are metarterioles?
Arteries that supply blood to capillary beds
What is a pre capillary sphincter?
Allow the arterioles and metarteroiles to serve as flow regulaters for capillary bed
What do lymphatic capillaries do?
They drain away excess extracellular fluid, returning it to the blood at the junctions of the internal jugular vein and subclavian vein
When and where is blood velocity at its lowest?
When it is passing through the capillaries, to allow sufficient time for gas exchange!
What r is the capillaries composed of?
Endothelium and its basement membrane
What r pericytes?
Cells that Form a branching network on the outer surface of capillaries and have the ability ro divide into muscle cells or fibroblasts during angiogenesis or tumor growth
Why r veins called capacitance vessels?
Bc they can increase the volume of blood it hold without causimg an imcrease in pressure, and since they have non elastic properties, they cam stretch a great deal without rising pressure
