Chapter 14

What are the two main components of whole blood?

Plasma and formed elements (RBCs, WBCs, platelets).

What percentage of blood is plasma?

55%

What percentage of blood is formed elements?

45%

What percentage of plasma is water?

91.5%.

What percentage of plasma are solutes?

8.5%.

Name the three major plasma proteins.

Albumin, globulins, fibrinogen.

What is the role of albumin in blood?

Maintains oncotic pressure and prevents fluid loss from capillaries.

What happens if albumin levels drop?

Causes fluid shifts into tissues, leading to edema.

What is the function of globulins?

Responsible for immune function (gamma globulins = antibodies).

What is fibrinogen and its clotting factor number?

Plasma protein involved in clotting; Factor I.

What does fibrinogen convert into during clot formation?

Fibrin.

What is bilirubin?

A waste product formed from hemoglobin breakdown.

What are the formed elements of blood?

RBCs, WBCs, and platelets.

What is hematocrit?

Percentage of blood volume composed of RBCs.

What does low hematocrit indicate?

Anemia or blood loss.

What does high hematocrit indicate?

Polycythemia or dehydration.

What is erythropoiesis?

Production of red blood cells.

What stimulates erythropoiesis?

Hypoxia.

What hormone stimulates RBC production?

Erythropoietin (EPO).

What is the normal RBC count?

Approximately 5.4 million/µL.

What is the normal reticulocyte count?

0.5–1.5%.

What does a reticulocyte count measure?

The rate of RBC production.

What is the lifespan of an RBC?

About 120 days.

What is the shape of an RBC?

Biconcave disc.

Why do RBCs lack a nucleus?

To maximize space for hemoglobin.

What is oxyhemoglobin?

Hemoglobin bound to oxygen.

What is carbaminohemoglobin?

Hemoglobin bound to carbon dioxide.

What happens when RBCs break down?

Hemoglobin splits into globin and heme.

What happens to globin after RBC breakdown?

Broken into amino acids reused for protein synthesis.

What happens to heme after RBC breakdown?

Converted to biliverdin then bilirubin, eventually forming bile.

Where is bile stored?

In the gallbladder.

What is nitric oxide's role in blood?

It causes vasodilation.

What is the normal WBC count?

5,000–10,000/mm³.

What is leukocytosis?

Elevated white blood cell count.

What is leukopenia?

Low white blood cell count.

Which WBC is most abundant?

Neutrophils

Which WBC increases in bacterial infections?

Neutrophils.

Which WBC increases during allergic reactions?

Eosinophils.

What do basophils release?

Histamine and heparin.

What do monocytes become in tissues?

Macrophages.

What do B lymphocytes produce?

Antibodies.

What do T lymphocytes do?

Directly attack infected or abnormal cells.

What is MHC?

Major histocompatibility complex; surface proteins that identify self vs non-self.

What is thrombopoiesis?

Production of platelets.

What hormone stimulates platelet production?

Thrombopoietin.

What are the three steps of hemostasis?

Vascular spasm, platelet plug formation, coagulation.

What is Hageman factor and its number?

Factor XII; initiates intrinsic pathway.

What triggers the extrinsic pathway?

Tissue thromboplastin from damaged tissue.

What is thrombosis?

A clot forming inside a vessel.

What is embolism?

A clot that travels and blocks another vessel.

What is the primary function of capillaries?

Exchange of gases, nutrients, hormones, and wastes.

What is the most common mechanism of capillary exchange?

Diffusion.

Which capillaries are least leaky?

Continuous capillaries.

Where are continuous capillaries found?

Muscle, skin, nervous tissue.

Which capillaries are moderately leaky?

Fenestrated capillaries.

Where are fenestrated capillaries found?

Kidneys, small intestine, endocrine glands.

Which capillaries are most leaky?

Sinusoidal (discontinuous) capillaries.

Where are sinusoidal capillaries found?

Liver, spleen, red bone marrow.

Where is most blood volume located in the body?

Systemic veins and venules.

What does it mean that venules anastomize?

They form interconnected networks.

What does a CBC measure?

RBCs, WBCs, and platelets.

What does a WBC differential measure?

Percentage of each type of white blood cell.

What does blood typing determine?

Presence of A, B, and Rh antigens.