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31 terms

Ch21 A&P2 Blood Vessels & Hemodynamics

Questions and answers to the figure questions.
Which vessel ~ the femoral artery or the femoral vein~ has a thicker wall? Which has a wider lumen?
The femoral artery has the thicker wall: the femoral vein has the wider lumen.
In artherosclerosis, the walls of elastic arteries become less compliant (stiffer). What effect does reduced compliance have on the pressure reservoir function of arteries?
Due to artherosclerosis, less energy is stored in the less-compliant elastic arteries during systole: thus, the heart must pump harder to maintain the same rate of blood flow.
Why do metabolically active tissues have extensive capillary networks?
Metabolically active tissues use O2 and proceed wastes more rapidly than inactive tissues, so they require more extensive capillary networks.
How do materials move through capillary walls?
Materials cross capillary walls through intercellular clefts and fenestrations, via transcytosis in pinocytic vesicles, and through the plasma membranes of endothelial cells.
Why are valves more important in arm veins and leg veins than in neck veins?
Valves are more important in arm veins and leg veins than in neck veins because, when you are standing, gravity cause pooling of blood in the veins of the free limbs but aids the flow of blood in neck veins back toward the heart.
If your total blood volume is 5 liters, what volume is in your venules and veins right now? In your capillaries?
Blood volumen in venules and veins is about 64% of 5 liters, or 3.2 liters; blood volume in capillaries is about 7% of 5 liters, or 350 mL.
A person who has liver failure cannot synthesize the normal amount of plasma proteins. How does a deficit of plasma proteins affect blood colloid osmotic pressure, and what is the effect on capillary exchange?
Blood colloid osmotic pressure is lower than normal in a person with a low level of plasma proteins, and therefor capillary reabsorption is low. The result is edema.
Is the mean blood pressure in the aorta closer to systolic or to diastolic pressure?
Mean blood pressure in the aorta is closer to diastolic than to systolic pressure.
Aside from cardiac contractions, what mechanisms act as pumps to boost venous return?
The skeletal muscle pump and respiratory pump aid venous return.
Which type of blood vessel exerts the major control of systemic vascular resistance, and how does it achieve this?
Vasodilation and vasoconstriction of arterioles are the main regulators of systemic vascular resistance.
In which blood vessels is the velocity of flow fastest?
The velocity of blood flow is fastest in the aorta and arteries.
What types of effector tissues are regulated by the cardiovascular center?
The effector tissues regulated by the cardiovascular center are cardiac muscle in the heart and smooth muscle in blood vessel walls.
Which cranial nerves conduct impulses to the cardiovascular center from baroreceptors in the carotid sinuses and the arch of the aorta?
Impulses to the cardiovascular center pass from baroreceptors in the carotid sinuses via the glossopharyngeal (IX) nerves and from baroreceptors in the arch of the aorta via the vagus (X) nerves.
When blood pressure decreases, heart rate increases.
Does this negative feedback cycle represent the changes that occur when you lie down or when you stand up?
It represents a change that occurs when you stand up because gravity causes pooling of blood in leg veins once you are upright, decreasing the blood pressure in your upper body.
If a blood pressure is reported as "142 over 95", what are the diastolic, systolic, and pulse pressures? Does this person have hypertension?
Diastolic pressure = 95 mmHg: systolic blood pressure = 142 mmHg; pulse pressure = 47 mmHg. This person has stage 1 hypertension because the systolic blood pressure is greater than 140 mmHg and the diastolic blood pressure is greater than 90 mmHg.
Does almost normal blood pressure in a person who has lost blood indicate that the patient's tissues are receiving adequate perfusion (blood flow)?
Almost normal blood pressure in a person who has lost blood does not necessarily indicate that the patient's tissues are receiving adequate blood flow; if systemic vascular resistance has increased greatly, tissue perfusion may be inadequate.
What are the two main circulatory routes?
The two main circulatory routes are the systemic circulation and the pulmonary circulation.
What are the four subdivisions of the aorta?
ascending aorta
arch of the aorta
thoracic aorta
abdominal aorta
What are the three major branches of the arch of the aorta, in order of their origination?
Branches of the arch of the aorta (in order of origination) are the brachiocephalic trunk, left common carotid artery, and left subclavian artery.
Where does the abdominal aorta begin?
The abdominal aorta begins at the aortic hiatus in the diaphragm.
Where does the thoracic aorta begin?
The thoracic aorta begins at the level of the intervertebral disc between T4 and T5.
At what point does the abdominal aorta divide into the common iliac arteries?
The abdominal aorta divides into the common iliac arteries at about the level of L4.
Which general regions of the body are drained by the superior vena cava and the inferior vena cava?
The superior vena cava drains regions above the diaphragm, and the inferior vena cava drains regions below the diaphragm.
Into which veins in the neck does all venous blood in the brain drain?
All venous blood in the brain drains into the internal jugular veins.
From which vein in the upper limb is a blood sample often taken?
The median cubital vein of the upper limb is often used for drawing blood.
Which vein returns blood from the abdominopelvic viscera to the heart?
The inferior vena cava returns blood from abdominopelvic viscera to the heart.
Which veins of the lower limb are superficial?
Superficial veins of the lower limbs are the dorsal venous arches and the great saphenous and small saphenous veins.
Which veins carry blood away from the liver?
The hepatic veins carry blood away from the liver.
Which structure provides for exchange of materials between mother and fetus?
Exchange of materials between mother and fetus occurs across the placenta.
From which germ cell layer are blood vessels and blood derived?
Blood vessels and blood are derived from the mesenchyme.
After birth, which are the only arteries that carry deoxygenated blood?
After birth, the pulmonary arteries are the only arteries that carry deoxygenated blood.