Blood Cells, Blood Types, and Hemostasis

Flashcards reviewing hematopoiesis, red bone marrow, blood types, Rh factors, blood gases, and hemostasis.

What is hematopoiesis?

The formation of blood cells.

What are hematopoietic stem cells, and what do they differentiate into?

Immature cells called hemocytoblasts that differentiate into erythrocytes, platelets, and leukocytes as they develop.

How is differentiation defined in the context of maturing blood cells?

The process through which maturing cells take on a more specific form and function.

Where does blood cell formation take place before birth in a developing embryo?

Mainly in the spleen, liver, and bone marrow of the developing embryo.

Where does hematopoiesis occur throughout life after birth?

In the red bone core of most bones.

How many cells are produced daily to continuously renew the body's blood supply?

More than 100,000,000,000 cells every day.

What is peripheral blood?

The blood circulating throughout the body.

What are reticulocytes, and how long do they take to mature in the bloodstream?

Red blood cells that have just been released from the bone marrow; they mature in about a day in the bloodstream.

What does the reticulocyte count in a blood sample indicate?

How well the bone marrow, liver, and kidneys are functioning, or extensive blood loss if the count is high.

Where do B cells and T cells mature?

B cells mature in the bone marrow, while T cells migrate to and mature in the thymus, where they are referred to as thymocytes.

What is an antigen?

Any substance that the body regards as being foreign, thus sometimes triggering an adverse reaction.

What determines the A, AB, and B blood groups?

The presence of the A and/or B antigens on the red blood cells.

What does the 'O' in type O blood represent?

It represents a zero, referring to the lack of either A or B antigens.

Why is the Rh factor named 'Rh'?

Because its antigen was first found in rhesus monkeys.

What percentage of Americans are Rh positive versus Rh negative?

About 85 percent are Rh positive (have the Rh antigen) and the remaining 15 percent are Rh negative (do not have the Rh antigen).

How are ABO blood group genes inherited from biological parents?

Each biological parent donates one ABO gene to their child; the A and B genes are dominant and the O gene is recessive.

What medication is given during pregnancy if an Rh-negative mother carries an Rh-positive fetus, and why?

Rhod immunoglobulin or Rhodium is administered to prevent the mother's body from producing Rh antibodies that might harm the fetus.

Why is type O negative blood considered a universal donor for red blood cells?

Because it does not contain any antigens.

What blood types can an Rh-positive individual receive compared to an Rh-negative individual?

Rh-positive individuals can receive either Rh-positive or Rh-negative blood, whereas Rh-negative individuals can only receive Rh-negative blood.

Which two blood types account for about 70 percent of all people in the United States?

O positive and A positive.

What are the major blood gases dissolved in the fluid portion of blood?

Oxygen ($O_2$), carbon dioxide ($CO_2$), and nitrogen ($N_2$).

How does the human body obtain the nitrogen it needs?

From food and water, because the human body cannot absorb nitrogen in its gaseous form.

What is hemostasis and how does the body attempt to achieve it?

Hemostasis means to stop or control bleeding; the body constricts an injured blood vessel and activates factors that cause platelets and proteins to form a clot.

What is mechanical hemostasis?

The use of external means, such as a tourniquet, to stop the flow of blood during surgery or in an emergency.

How do thrombin and fibrinogen function in blood coagulation?

They are blood plasma proteins that act as clotting agents; when activated by an injury, fibrinogen forms a web-like material called fibrin that aids in clot and scab formation.

How does increased formation of fibrin affect aging bodies?

It can increase the risk of dangerous blood clots.