Flashcards in Short review for Human Phys Chapter 8 and atherosclerosis Deck (44):
All blood pumped by the right side of the heart goes into the _________ circulation, whilst all the blood pumped from the left side of the heart goes through the ___________ circulation.
What are examples of organs that recondition blood?
Kidneys, digestive tract, skin.
What does reconditioning of the blood mean?
keeps the conditions of the blood constant.
How do the kidneys recondition blood?
Eliminate metabolic wastes, adjust water and electrolyte composition.
How does the digestive system recondition the blood?
Supplies nutrients to the blood.
How does the skin recondition the blood?
Brings blood to the surface of the skin to eliminate heat.
What is peculiar of the organs that recondition blood, in terms of receiving blood?
They receive an excess of blood than is metabolically needed, thus, they can withstand periodic losses in blood.
An example is during exercise, blood is routed to the skeletal muscles instead.
What organ can withstand loss of blood the least?
What is flow rate?
The volume of blood passing through a blood vessel per unit of time.
What is the flow rate dependent on?
Resistance and the pressure gradient.
What is the pressure gradient?
The difference between the pressure at the beginning and the pressure at the end of a vessel.
Not to be confused with the absolute pressure within a vessel.
Blood flows from an area of _____ pressure to an area of _________ pressure.
What effect does vessel length have on pressure?
Longer vessels have a decrease in pressure due to frictional losses.
What is resistance?
Which is a measure of the hindrance or opposition of blood flow through a vessel, caused by friction between the moving fluid and the stationary vascular walls.
What three factors affect resistance?
1. viscosity of the blood
2. vessel length
3. vessel radius
How does viscosity affect resistance?
Blood viscosity is contingent on the RBC content, and the greater the viscosity, the greater the resistance.
How does radius affect resistance?
Larger radius imparts less resistance.
What is the vascular tree?
Arteries branch into small arteries which branch into numerous arterioles when reaching the organ that is being supplied. These further branch into capillaries, then into venules, small veins then veins.
What is the microcirculation?
The arterioles, capillaries and venules, located within the organs. Can only be seen by microscope.
What is the general composition of blood vessel walls?
Alternating layers of connective tissue (both fibrous and elastic), smooth muscle cells and epithelial cells.
What are the different layers?
tunica adventitia (outer layer), tunica media (middle layer), tunica intima (innermost layer) and sometimes the external elastic lamina (between the outermost and middle layer).
What is the tunica adventitia?
The outermost layer, mainly composed of collagen-rich connective tissue.
What is the tunica media?
Middle layer, thickest and contains circular arrangements of connective tissue and smooth muscle cells.
What is the external elastic lamina?
Found in some vessels, between the adventitia and media. It is an elastic rich area.
What is the tunica intima?
comprised of a single layer of endothelial cells (the endothelium) surrounded by a basement membrane of connective tissues, and in some vessels, an additional layer of elastic fibres called the internal elastic lamina.
What are arteries specialized for?
1. Serve as rapid-transient passageways for blood from the heart to the organs.
2. act as pressure reservoirs to provide the force to drive blood during ventricular diastole
Arterial connective tissue contains an abundance of two types of connective tissue. What are they?
Collage fibres, which provide tensile strength against the high driving pressure of blood ejected from the heart.
Elastin fibres, which give the arterial walls elasticity.
What is the process of blood reservoir?
When the heart contracts, blood is forced through the arteries. However, the smaller arteries only allow 1/3 of the blood through, thus the larger arteries elastin fibres lead the artery to stretch, to store the blood. Then, during diastole, the walls recoil and force the blood onward.
What is blood pressure?
The force exerted by the blood against the vessel wall.
What is blood pressure dependent on?
1-volume of blood contained in the blood vessel
2-the compliance (how easily the vessel can be stretched) of the vessel wall
What is the maximum pressure in the arteries?
Systolic pressure, avg of 120 torr.
What is the minimum pressure within the arteries?
Diastolic pressure, avg. of 80 torr.
How can blood pressure be measured?
Using a sphygmomanometer. (fuck this word)
Where is the sphygmomanometer applied?
To the brachial artery.
What other instrument is used with a sphygmomanometer?
What is the general process of blood pressure determination?
Cuff is inflated until circulation is cut off in the brachial artery. Then pressure in the cuff is decreased. The first sound heard by the stethoscope corresponds to the small amount of blood that leaves through the partially closed artery-this is the systolic pressure. The last sound heard (during the systole, diastole cycle) corresponds to the diastolic pressure.
What is pulse pressure?
The pulse that can be felt in an artery close to the surface of the skin is due to the difference in systolic and diastolic pressure. So in normal conditions, it is 40 torr.
What is the mean arterial pressure?
Average pressure driving blood forward into the tissues throughout the cardiac cycle. Mean arterial pressure remains closer to diastolic pressure. A method to calculate it is diastolic + 1/3 pulse pressure. (so 93 in normal conditions)
What is hypertension?
Chronically high blood pressure,
What are the two types of hypertension?
Secondary-occurs secondary to another primary problem or
Primary- in which the cause is unknown but is highly genetic.
How can primary hypertension be hastened?
Stress, Obesity, smoking, dietary habits.
What does hypertension do, in terms of the heart, and blood vessels?
Increased the workload of the heart because it is pumping against higher arterial pressure. This pressure can lead to rupturing of vessels.
How do beta blockers decrease blood pressure?
Block beta-adrenergic receptors and decrease the effects of sympathetic stimulation through adrenaline and noradrenaline.