Chapter 10 Blood and Circulatory System Disorders

What are the two main systems that make up the circulatory system?

The cardiovascular system (heart and vessels) and the lymphatic system.

What is the primary function of arteries?

To transport blood away from the heart.

What is the primary function of veins?

To return blood back to the heart.

Explain the difference between systemic and pulmonary circulation.

Systemic circulation involves the exchange of gases, nutrients, and wastes throughout the body, while pulmonary circulation is specific to gas exchange in the lungs.

What are the three main functions of blood?

Transporting oxygen/nutrients, removing waste products, and playing a key role in the body's defense and homeostasis.

What are the three types of cellular components in blood?

Red blood cells (RBCs/erythrocytes), white blood cells (WBCs/leukocytes), and platelets (thrombocytes).

What is hematopoiesis and where does it occur?

Hematopoiesis is the process of forming blood cells, which originates from a single stem cell in the red bone marrow.

What is the approximate lifespan of a mature red blood cell?

120 days.

What hormone stimulates the production of red blood cells (erythrocytes) and where is it produced?

Erythropoietin, which is produced in the kidney in response to tissue hypoxia.

What are the three layers that make up the walls of arteries and veins?

The tunica intima (inner), tunica media (middle), and tunica adventitia (outer).

What does hematocrit measure?

The proportion of cells (specifically erythrocytes) in the blood, which indicates blood viscosity.

What determines a person's ABO blood type?

The presence or absence of specific antigens (A or B) on the plasma membrane of their erythrocytes.

Why is a person with type O negative blood considered a "universal donor"?

Because their red blood cells have no A, B, or Rh antigens to cause an immune reaction in the recipient.

Why is a person with type AB positive blood considered a "universal receiver"?

Because their blood plasma has no antibodies against A, B, or Rh antigens, so they can receive any blood type.

What does leukocytosis, an increased WBC count, often indicate?

Inflammation or infection.

What does leukopenia, a decreased WBC count, often indicate?

Some viral infections, or exposure to radiation or chemotherapy.

What do prothrombin time (PT) and partial thromboplastin time (PTT) measure?

They measure the function of various factors in the coagulation process and are used to monitor anticoagulant therapy.

How is bone marrow function assessed through a diagnostic test?

By a reticulocyte (immature RBC) count or a bone marrow aspiration and biopsy.

What does the term "pancytopenia" mean?

It describes a deficiency of all three blood cell types: red blood cells (anemia), white blood cells (leukopenia), and platelets (thrombocytopenia).

What is a differential WBC count used for?

To determine the proportions of specific types of WBCs, which can help in making a diagnosis.

What is the fundamental problem common to all anemias?

A deficit in hemoglobin, which causes a reduction in the oxygen-transporting capacity of the blood.

What are four general signs of anemia that result from the body's compensation mechanisms for hypoxia?

Fatigue, pallor (pale skin), dyspnea (difficulty breathing), and tachycardia (rapid heart rate).

Describe the characteristic appearance of red blood cells in iron deficiency anemia.

They are microcytic (small) and hypochromic (pale) due to low hemoglobin concentration.

Why is pernicious anemia caused by a vitamin B12 deficiency?

It results from a lack of intrinsic factor, a substance produced by the gastric mucosa that is required to absorb vitamin B12 in the intestine.

What critical role, besides RBC production, does vitamin B12 play in the body?

It is essential for the function and maintenance of neurons in the nervous system

What are the characteristic red blood cells in pernicious anemia called?

Megaloblasts, which are very large, immature, and nucleated erythrocytes.

What is aplastic anemia?

Anemia caused by the impairment or failure of bone marrow, leading to pancytopenia (a decrease in all blood cell types).

What does "idiopathic" mean in the context of a disease like aplastic anemia?

The cause of the disease is unknown.

What is hemolytic anemia?

Anemia resulting from the excessive destruction (hemolysis) of red blood cells.

Explain the underlying genetic cause of sickle cell anemia.

An inherited recessive gene causes an amino acid substitution in the hemoglobin molecule (HbS), which deforms the RBC into a sickle shape when deoxygenated.

At what age do clinical signs of sickle cell anemia typically appear, and why?

Around 12 months old, which is when fetal hemoglobin (HbF) has been replaced by the abnormal hemoglobin S (HbS).

What is the primary danger during a sickle cell crisis?

The rigid, sickle-shaped cells obstruct small blood vessels, leading to tissue ischemia, multiple infarctions (tissue death), and severe pain.

What is thalassemia?

A genetic disorder where one or more genes for hemoglobin are missing or variant, reducing the amount of hemoglobin synthesized.

Explain why a person with severe anemia might experience angina (chest pain).

The reduced oxygen supply to the heart muscle, especially during stressful situations, can cause chest pain.

Describe the three main steps of hemostasis (stopping bleeding).

1. Vasoconstriction, 2. Platelet plug formation, and 3. The coagulation mechanism (clotting cascade).

What role does Vitamin K play in coagulation?

It is a fat-soluble vitamin required for the synthesis of most clotting factors in the liver.

What is fibrinolysis?

The natural process of breaking down newly formed clots, involving the conversion of plasminogen to plasmin.

What is hemophilia A?

The most common inherited clotting disorder, caused by a deficit or abnormality of clotting factor VIII.

Why is hemophilia A manifested in men but carried by women?

It is an X-linked recessive trait, so women are typically carriers while men, having only one X chromosome, will manifest the disease if they inherit the gene.

What is Disseminated Intravascular Coagulation (DIC)?

A life-threatening condition involving both excessive clotting and excessive bleeding simultaneously, which depletes clotting factors and leads to hemorrhage.

What are petechiae?

Pinpoint, flat red spots on the skin or mucous membranes that result from bleeding from small capillaries.

How might severe liver disease lead to a bleeding disorder?

The liver produces most clotting factors and is necessary for absorbing and using Vitamin K, both essential for coagulation.

What is thrombophilia?

A group of inherited or acquired disorders that increase the risk of developing abnormal clots (thrombosis) in veins or arteries.

Why should a person with a bleeding disorder avoid taking aspirin (ASA)?

Aspirin reduces platelet adhesion, which can increase the tendency to bleed.

What is the difference between primary polycythemia (polycythemia vera) and secondary polycythemia?

Primary polycythemia is a neoplastic disorder causing overproduction of RBCs, while secondary polycythemia is a compensatory increase in RBCs due to prolonged hypoxia.

How are acute and chronic leukemias different?

Acute leukemias have an abrupt onset with a high proportion of immature, non-functional "blast" cells. Chronic leukemias have an insidious onset with more mature-looking cells that have reduced function.

What are the four major types of leukemia?

Acute Lymphocytic Leukemia (ALL), Acute Myelogenous Leukemia (AML), Chronic Lymphocytic Leukemia (CLL), and Chronic Myelogenous Leukemia (CML).

Which type of leukemia is most common in young children?

Acute Lymphocytic Leukemia (ALL).

Why are patients with leukemia prone to frequent and severe infections?

The bone marrow is crowded with nonfunctional cancerous WBCs, which suppresses the production of normal, functional leukocytes needed to fight infection.

What are some common signs at the onset of acute leukemia?

Unresponsive infections, severe hemorrhage (due to low platelets), anemia, and severe, steady bone pain.

What is multiple myeloma?

A neoplastic disease involving the increased production of cancerous plasma cells in the bone marrow, leading to bone destruction and impairing the production of other blood cells.

Why does severe bone pain occur in patients with leukemia?

The proliferation of leukemic cells crowds the bone marrow, increasing pressure on nerves within the rigid bone and stretching the periosteum.

What is myelodysplastic syndrome (MDS)?

A group of diseases involving inadequate production of blood cells by the bone marrow, which can sometimes progress to leukemia.

Why might a patient with polycythemia experience headaches or visual disturbances?

The increased blood volume and viscosity lead to sluggish blood flow and distended blood vessels, affecting circulation to the brain.

What is Epoetin alfa (Procrit)?

An artificial form of erythropoietin used to stimulate the production of red blood cells in patients with certain types of anemia.

What is the purpose of periodic phlebotomy in treating polycythemia vera?

To remove blood, thereby reducing blood volume and viscosity to minimize the risk of thrombosis or hemorrhage.

Why is a close tissue match (HLA match) necessary for a bone marrow transplant?

To minimize the risk of the recipient's body rejecting the donor's stem cells.

What is the main treatment for leukemia?

Chemotherapy.

What type of blood product would be given for severe anemia?

Packed red blood cells.

What is the treatment for hemophilia A?

Replacement therapy with factor VIII or medication like desmopressin (DDAVP) that raises factor VIII levels.

What are "clot-buster" drugs like streptokinase used for?

To break down newly formed clots (fibrinolysis) in conditions like strokes or heart attacks.

What is chelation therapy used for in blood disorders?

To remove excess iron from the body, which can accumulate from frequent blood transfusions.

How do biologic therapies like interferon work in treating cancer?

They stimulate the body's own immune system to help fight the cancer cells.

Why might a patient with pernicious anemia require vitamin B12 injections rather than oral supplements?

Because the condition is caused by a lack of intrinsic factor needed for oral absorption, so injections bypass the digestive system.

In cases of severe bleeding, what can be administered to maintain blood volume?

Plasma or colloid volume-expanding solutions.

Rh system

Rh+/Rh-

eosinophils cause

allergic rxns

von willebrand disease

most common hereditary clotting disorder