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The myocardium receives its blood supply from the coronary arteries.

True

Cardiac muscle has more mitochondria and depends less on a continual supply of oxygen than does skeletal muscle.

False

Anastomoses among coronary arterial branches provide collateral routes for blood delivery to the heart muscle.

True

Congestive heart failure means that the pumping efficiency of the heart is depressed so that there is inadequate delivery of blood to body tissues.

True

The "lub" sounds of the heart are valuable in diagnosis because they provide information about the function of the heart's pulmonary and aortic valves.

False

Autonomic regulation of heart rate is via two reflex centers found in the pons.

False

If we were able to artificially alter the membrane permeability of pacemaker cells so that sodium influx is more rapid, ________.

threshold is reached more quickly and heart rate would increase

Select the correct statement about cardiac output.

A slow heart rate increases end diastolic volume, stroke volume, and force of contraction.

During contraction of heart muscle cells ________.

some calcium enters the cell from the extracellular space and triggers the release of larger amounts of calcium from intracellular stores

Select the correct statement about the structure of the heart wall.

The myocardium is the layer of the heart that actually contracts.

Compared to skeletal muscle, cardiac muscle ________.

has gap junctions that allow it to act as a functional syncytium

Site where resistance to blood flow is greatest.

Arterioles

Site where exchanges of food and gases are made.

Capillaries

Site where blood pressure is lowest.

Large veins

Vasodilation is a widening of the lumen due to smooth muscle contraction.

False

The pulmonary circulation does not directly serve the metabolic needs of body tissues.

True

An obstruction in the superior vena cava would decrease the flow of blood from the head and neck to the heart.

True

Arteries supplying the same territory are often merged with one another, forming arterial anastomoses.

True

Which of the following is not one of the three main factors influencing blood pressure?

emotional state

Which of the following chemicals does not help regulate blood pressure?

nitric acid

Which statement best describes arteries?

All carry blood away from the heart.

Which tunic of an artery is most responsible for maintaining blood pressure and continuous blood circulation?

tunica media

Peripheral resistance ________.

increases as blood viscosity increases

In the dynamics of blood flow through capillaries, hydrostatic pressure ________.

is the same as capillary blood pressure

The hepatic portal vein ________.

carries nutrient-rich blood to the liver

Which of the following blood pressure readings would be indicative of hypertension?

170/96 in a 50-year-old man

Select the correct statement about factors that influence blood pressure.

Excess red cell production would cause a blood pressure increase.

Chyle is delivered to the blood via the lymphatic system.

True

All lymphoid organs develop from mesoderm.

False

About 3 liters of fluid are lost to the tissue spaces every 24 hours and are returned to the bloodstream as lymph.

True

Because lymph vessels are very low-pressure conduits, movements of adjacent tissues are important in propelling lymph through the lymphatics.

True

When tissues are inflamed, lymphatic capillaries develop openings that permit uptake of large particles such as cell debris, pathogens, and cancer cells.

True

The cisterna chyli collects lymph from the lumbar trunks draining the upper limbs and from the intestinal trunk draining the digestive organs.

False

The thymus is most active during ________.

childhood

Which lymphatic structure drains lymph from the right upper limb and the right side of the head and thorax?

right lymphatic duct

What effect does age have on the size of the thymus?

The thymus initially increases in size and then decreases in size from adolescence through old age.

The lymphatic capillaries are ________.

more permeable than blood capillaries

Select the correct statement about lymphoid tissue.

Lymphoid tissue is predominantly reticular connective tissue.

Which of the following are functions of lymphoid tissue?

A)house and provide a proliferation site for lymphocytes
C) furnish an ideal surveillance vantage point for lymphocytes and macrophages

What is a bubo?

an infected lymph node

Cardiac muscle has more mitochondria and depends less on a continual supply of oxygen than does skeletal muscle.

False

As pressure in the aorta rises due to atherosclerosis, more ventricular pressure is required to open the aortic valve.

True

Normal heart sounds are caused by which of the following events?

closure of the heart valves

Damage to the ________ is referred to as heart block.

AV node

The P wave of a normal electrocardiogram indicates ________.

atrial depolarization

To auscultate the aortic semilunar valve, you would place your stethoscope in the ________.

second intercostal space to the right of the sternum

Norepinephrine acts on the heart by ________.

causing threshold to be reached more quickly

If the vagal nerves to the heart were cut, the result would be that ________.

the heart rate would increase by about 25 beats per minute

During the period of ventricular filling ________.

blood flows passively through the atria and the open AV valves into the ventricles

Why is fibrosis of the cardiac muscle serious?

With fibrosis the heart muscle stiffens and is unable to fill the atria as it once did; therefore, less blood is pumped. Further, as the muscle stiffens it takes more energy to expel the bolus of blood from the heart, which will eventually weaken the heart.

A man enters the hospital complaining of chest pain. His history includes smoking, a stressful job, a diet heavy in saturated fats, lack of exercise, and high blood pressure. Although he is not suffering from a heart attack, his doctor explains to him that a heart attack is quite possible.

What did the chest pain indicate? Why is this man a prime candidate for a heart attack?

His symptoms indicate angina pectoris, possibly due to either atherosclerosis or stress-induced spasms of the coronary arteries. If the arteries are occluded (atherosclerosis), the heart muscle could be deprived of blood, and therefore oxygen. A heart attack could occur if the coronary vessels experience further (or progressive) occlusion.

A patient takes a nitroglycerin tablet sublingually for chest pain. Nitroglycerin acts directly on smooth muscle, producing relaxation and vessel dilation. How would this relieve chest pain?

Angina pectoris is thoracic pain caused by a fleeting deficiency in blood delivery to the myocardium, with resulting decreased oxygen being delivered to the cells. Because nitroglycerin acts as a vasodilator, blood flow is increased, promoting the delivery of oxygen to the cells.

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