The atrioventricular (AV) node is located in the

What part of the cardiac conduction system is located in the posterior wall of the right atrium, adjacent to the entrance of the superior vena cava?

During a cardiac cycle, how many of the four chambers contract at any one time?

As blood is pumped out of the heart and into the major arteries leaving the heart, it

Occlusion of blood vessels tends to lead to

The units for perfusion of blood are typically

During ventricular contraction

How many half-moon shaped, pocketlike cusps are found in each semilunar valve?

During the S-T segment, what is occurring within cardiac muscle cells?

The opening and closing of the heart valves is caused by

The plateau phase of an action potential

Purkinje fibers are small fibers within the atria that conduct impulses rapidly.

Which describes the endocardium? a: Has single layer of epithelium b: Has layer of areolar connective tissue c: Epithelial cells are squamous d: Epithelial cells are cuboidal e: Has layer of adipose connective tissue f: Has patches of myocardium

The layer of the heart wall composed of cardiac muscle tissue is the

Which action leads tothe closure of the right atrioventricular valve?

Metabolically, cardiac muscle relies on

Most of the calcium that triggers contraction of cardiac muscle comes

Which carries oxygenated blood from the lungs to the heart?

Immediately prior to atrial contraction, blood continues to enter the atria from the venae cavae and pulmonary veins.

Nodal cells contain fast voltage-gated calcium channels.

Cardiac muscle is able to use a variety of fuel types for cellular respiration.

The pericardial cavity is between the

For the repolarization phase of an SA nodal cell action potential,

Which segment of the ECG reflects the plateau phase of ventricular muscle cells' action potentials?

The metabolic pathways of cardiac muscle make it

Glucose is a

Simply put, antibodies are molecules on the lookout for antigens.

The type of leukocyte that is very active during a bacterial infection is a(n)

Platelets are roughly the same size as erythrocytes, and like erythrocytes, they eject their nucleus just before entering circulation.

Which type of leukocyte releases histamine?

Which events occur during the recycling of aged or damaged erythrocytes? (Order is not important.) a: The heme group is converted into biliverdin. b: Bilirubin is placed in long-term storage in the liver. c: The iron ions in hemoglobin are removed. d: The iron ions are stored in the liver. e: The iron ions are stored in the red bone marrow. f: Membrane proteins and globin proteins are broken down and reused. g: The erythrocyte contents, excluding the globins, are excreted unchanged via the digestive tract.

Macrophages are the converted monocytes that phagocytize bacteria, cell fragments, dead cells, and debris.

During hemopoiesis, the lymphoid line forms lymphocytes only.

The agglutinogens (or antigens) that determine the ABO and Rh blood types are

Macrophage colony-stimulating factor stimulates the production of

Leukocytesare the _______ of the formed elements, and leukocytes have ______________.

The growth factor that increases the formation of erythrocytes, all classes of granulocytes, monocytes, and platelets from myeloid stem cells is

The “buffy coat" in a centrifuged blood sample is composed of

Blood plasma is slightly _______; if pH drifts out of the normal range, dire consequences can result from alterations in the structure of_______ .

Which term best describes the function of blood when considering the presence of leukocytes and antibodies?

Which clotting pathway involves the combining of thromboplastin (factor III) with factor VII and calcium?

Which most closely approximates the percentage of water in plasma by weight?

The main function of leukocytes is to

Which are characteristic of type Rh negative blood? a: Always has Rh (anti-D) antibodies b: Only under certain conditions will Rh (anti-D) antibodies be present c: Always has Rh (D) antigen d: Only under certain conditions will the Rh (D) antigen be present e: Is inherited independent of the ABO group

The type of leukocyte that will migrate in the blood and take up residence in the tissues as a macrophage is a(n)

Fibrinolysis involves ________ of the fibrin framework, and it involves the protein _______.

For a relatively small injury, a platelet plug is formed within 1 minute.

Vascular spasms last

One of the functions of blood is to regulate fluid levels in the body. If too much fluid escapes from the bloodstream and enters the tissues, blood pressure will

Which is going to result in significant agglutination?