How does amount of elastic tissue and smooth muscle differ between arteries and veins?
veins have less than arteries
How does the amount of fibrous tissue differ between arteries and veins?
veins contain more than arteries
What causes arterial blood pressure to increase?
increasing stroke volume, heart rate, arteriosclerosis, and blood volume
What results in the dilation of the feeder arterioles and opening of the precapillary sphincters in systemic capillary beds?
a decrease in local tissue oxygen content, an increase in local tissue CO2, and a local increase in histamine
What is the difference between the capillary wall of a vein and artery?
veins have one single tunic, the tunic intima
What are the baroreceptors in the carotid sinus and aortic arch sensitive to?
changes in arterial pressure
Blood flow in the capillaries is steady despite the rhythmic pumping of the heart because of what?
elasticity of the large arteries
What are the three branches off the aortic arch called?
brachiocephalic artery, left common coratid artery, and left subclavian vein
What drains directly into the inferior vena cava?
inferior phrenic veins, hepatic veins, and renal veins
When vascular smooth muscle contracts, what happens to the diameter of the blood vessel? What is this called?
the diameter of the blood vessel decreases; vasoconstriction
Which artery plays a major role in dampening the pulsatile pressure of heart contractions?
What artery allows vasodilation or constriction to determine blood flow to individual capillary beds?
In the systemic circuit, which contains more blood-arteries or veins- or is it the same?
veins contain more blood than arteries
Explain how renal artery obstruction could cause secondary hypertension
The blood pressure in the kidneys is lower than the rest of the body. This triggers direct and indirect renal mechanisms to increase blood pressure by increasing blood volume.
Suppose you are in a bicycle race. What happens to the smooth muscle in the arterioles supplying your leg muscles? What is the key mechanism in this case?
The smooth muscle relaxes, dilating the vessels and supplying more oxygen and nutrients to the exercising muscles; autoregulation by intrinsic metabolic controls
If many arterioles in your body dilated at once, you would expect MAP to plummet. What prevents MAP from decreasing during your bicycle race?
extrinsic mechanisms, primarily the SNS, and cardiac output increases
Which paired artery supplies most of the tissues of the head except for the brain and orbits?
the external carotid arteries
What is the name of the arterial anastomosis at the base of the brain?
the cerebral arterial circle, aka the circle of willis
What is the name of the 4 unpaired arteries that emerge from the abdominal aorta?
celiac trunk, superior and inferior mesenteric arteries, and the median sacral artery
Which veins drain the dural sinuses and where do these veins terminate?
the internal jugular veins; each internal jugular vein joins a subclavian vein to form a brachiocephalic vein
What is the function of the hepatic portal system?
to transport venous blood from the digestive organs to the liver for processing before it enters the rest of the systemic circulation
What are three differences between systemic arteries and veins with respect to their general pathways and courses?
arteries run deep, veins run deep and superficial, venous pathways are more interconnected than arterial pathways, the brain and digestive systems have unique venous drainage systems, and the arterial drainage system is not different
What are three common age-related vascular problems?
varicose veins, atherosclerosis, and hypertension
How do you calculate blood flow?
blood flow (F) = difference in blood pressure / peripheral resistance
What would be the approximate blood pressure in a blood vessel leaving the stomach for a person lying on her back (not standing) be?
below 20 mmHg
What is the most important force driving filtration at the arterial end of a capillary?
blood hydrostatic pressure
What increases capillary filtration?
obstructed venous return, blockage of lymphatic capillaries, dietary protein deficiency, and increased capillary permeability
What type of shock occurs when bacterial toxins trigger vasodilation and increases capillary permeability?
What can lead to edema?
hypertension, liver disease, vasoconstriction of arterioles leading to the capillary bed, obstruction of lymphatic vessels, and famine
What contributes to venous return?
the expansion and contraction of the thoracic cavity, contraction of skeletal muscles, activation of angiotensin II, the difference of pressure between venules and the vanae cavae, and the suction created by the atria slightly expanding during ventricular systole
What is the innermost layer of the pericardial sac called?
epicardium, or visceral layer of the serous pericardium
When will precapillary sphincters in systemic capillary beds dilate?
when exposed to high carbon dioxide, in areas of low oxygen, or when pH drops
The fight or flight response results in the constriction of what?
renal arteries, celiac trunk, and the internal iliac arteries
What is an exception to the normal effects of decreased oxygen on vasoconstriction?
If rising angiotensin II levels increased ADH, what would occur?
blood pressure would rise because of more water reabsorption
If the diameter of a vessel decreases, what would happen to the peripheral resistance? This change in diameter is most relevant in what?
it would increase; arterioles
The net filtration pressure of a blood capillary is the different between which two pressures?
net hydrostatic pressure and osmotic pressure
What is the outer wall of an artery or vein called? What does it contain in the large arteries and veins?
tunica externa; vasa vasorum
In a blood pressure ratio (x,y) what units is x measured in and what does it refer to?
millimeters of mercury; peak arterial pressure during systole