Chapter 13: Blood Functions and Components

Major functions of blood

Transportation, regulation, and protection are all general functions of blood that are vital to homeostasis.

Blood

The ONLY connective tissue (category blood falls under for its characteristics) with a fluid extracellular matrix (PLASMA).

Formed elements in blood

red blood cells, white blood cells, and platelets (which are cell fragments).

Hematocrit

Hematocrit (HCT) is the percentage of the red blood cells in a blood sample.

Determining hematocrit

This is obtained by allowing the sample to stand (clotting is prevented), allowing the cells to separate and sink to the bottom. This is further centrifuged, and the percentage of the cells and liquid is determined.

Liquid portion of blood

plasma.

Blood cell differentiation

Blood cells originate in red bone marrow from stem cells.

Red blood cell

A red blood cell is a biconcave disk that has no nucleus.

Oxyhemoglobin

Oxyhemoglobin is hemoglobin combined with oxygen.

Deoxyhemoglobin

Deoxyhemoglobin is hemoglobin that has released its oxygen.

Red blood cell count

A red blood cell count is the number of red blood cells in a cubic millimeter (mm3) of blood.

Life cycle of a red blood cell

Nutrients from food are absorbed from the small intestine into the bloodstream; the blood transports the absorbed nutrients to the red bone marrow tissue; the red bone marrow produces red blood cells; the red blood cells circulate for about 120 days; damaged and old red blood cells are destroyed in the liver; the resulting biliverdin is converted to bilirubin that is excreted in the bile from the liver.

Erythropoietin

Erythropoietin is a hormone that is released from the kidneys, and to a lesser extent the liver, which stimulates red blood cell production.

How does vitamin C affect iron absorption?

Obtaining vitamin C in the diet will increase iron absorption from the small intestine.

What happens to iron during red blood cell destruction?

Iron is conserved and reused from the red blood cell destruction.

Biliverdin

Biliverdin is the greenish pigment that results when the heme portion of the hemoglobin breaks apart.

Bilirubin

Bilirubin is what biliverdin eventually converts to over time.

Granulocytes

A granulocyte is a white blood cell that has granular cytoplasm (visible granules).

Agranulocytes

Agranulocytes are white blood cells that lack cytoplasmic granules (non-visible granules).

Neutrophils

Neutrophils are granulocytes that function to phagocytize foreign particles.

Eosinophils

Eosinophils are granulocytes that function to kill certain parasites and help control allergic reactions.

Basophils

Basophils are granulocytes that function to release heparin that inhibits blood clotting and release histamine to cause inflammation.

Monocytes

Monocytes are agranulocytes that leave the bloodstream to function as macrophages that phagocytize foreign particles.

Lymphocytes

Lymphocytes are agranulocytes that function to produce antibodies that act against specific foreign substances.

What is Leukopenia

< 5,000 WBC count; caused by viral diseases, chemo, glucocorticoids

Platelets

Platelets (thrombocytes) are fragments of megakaryocytes that function in the formation of blood clots.

Most abundant component of plasma

water (92% of plasma)

Types of plasma proteins

Albumins—help to maintain osmotic pressure of the blood; Globulins—help to transmit lipids and fat-soluble vitamins and are the antibodies of immunity;

Fibrinogen—precursor to fibrin that has a major role in blood clotting.

Gases in plasma

Gases in plasma include oxygen, carbon dioxide, and nitrogen.

Plasma nutrients

Plasma nutrients include amino acids, simple sugars, and lipids.

Most abundant plasma electrolytes

sodium and chloride.

Hemostasis

The term for stoppage of bleeding.

What is blood vessel spasm?

A contraction of smooth muscles in the wall of a blood vessel.

What stimulates a blood vessel spasm?

Cutting or breaking a blood vessel.

Platelet plug

Platelets adhering to form a plug that may control blood loss from a small break.

Blood clot

Required to halt bleeding from a larger break.

Positive feedback system

Once a blood clot starts to form, the promotion of blood clotting continues.

Rh-positive blood

Blood with Rh antigens present on the red blood cell membrane.

Rh-negative blood

Blood that lacks Rh antigens.

What is a universal recipient in blood types?

A person with blood type AB who can receive blood of any type.

What blood types can a person with AB+ receive?

All Rh+/- blood.

What blood types can a person with AB- receive?

Only Rh- blood.

Universal donor

A person with blood type O who can donate blood to any other type.

Erythroblastosis fetalis

A condition where an Rh-positive fetus has come into contact with anti-Rh antibodies through breaks in the placental membrane.

What is Anemia?

deficiency in red blood cells or hemoglobin (decreased O2 carrying capacity in both scenarios)

RBCs have no nucleus, what can it not do because of this?

RBCs cannot replicate, they must be produced in red bone marrow.

Can erythroblastosis lead to polycythemia or anemia in the newborn if it's not treated?

Anemia (particularly hemolytic anemia - a destruction of RBCs faster than they are produced)

What is diapedesis?

Diapedesis is the process by which cells move from the capillaries to the tissues in order to fight pathogens.

What is chemotaxis?

Chemotaxis is the method by which cells move in response to a chemical signal.

How do immune cells use chemotaxis?

Immune cells use chemotaxis to move to the tissues.

What is jaundice and how is it caused?

a buildup of bile pigments in the blood which are caused by liver disease, obstruction of bile ducts, or hemolytic anemia (destruction of RBCs that happens faster than RBCs are produced)

What is another name(s) for neutrophils?

polymorphonuclear cells (PMNs) and segmented neutrophils (segs)

This granulocyte has many lysosomes to breakdown captured bacteria

Neutrophils

Platelets are formed from what cells?

Megakaryocytes

What is it called when someone has a platelet deficiency?

Thrombocytopenia

What is the importance of B-cells?

produce antibodies

What is the importance of T-cells?

directly attack tumor cells, virus-infected cells

What leukocyte is slightly larger than erythrocytes, but is the smallest WBC?

Lymphocyte

What cell releases serotonin as a vasoconstrictor?

Thrombocytes (platelets)