Blood

• Transports essential oxygen to tissues along with nutrients required for cellular metabolism
• provides for the necessary removal of many cell wastes
• plays a critical role in the body's defenses/immune system
• serves in maintaining body homeostasis
• Provides a mechanism for controlling body temperature by distributing Core heat throughout the peripheral tissues

Two Separate Circulations

1. The pulmonary circulation
2. The systemic circulation

The Pulmonary Circulation

• allows The exchange of oxygen and carbon dioxide in the lungs

The Systemic Circulation

• Provides for the exchange of nutrients and wastes between the blood and the cells throughout the body

Arteries

• Transports Blood away from the heart

Arterioles

• The smaller branches of arteries
• Controls the amount of blood flowing into the capillaries in specific areas through the degree of contraction of smooth muscle in the vessel wall

Capillaries

• Very small vessels
• Forms the microcirculation
• Blood flow very slowly through capillaries
• precapillary sphincters
• Single endothelial layer
  • Facilitates the exchange of fluid, oxygen, carbon dioxide, electrolytes glucose, and other nutrients and waste between the blood and interstitial fluid

Precapillary Sphincters

• Determines the amount of blood flowing from the arterioles into the individual capillaries
• depends on the metabolic needs of the tissues

Small Venules

• conduct blood from the capillary beds toward the heart

Veins

• returns blood back to the heart
• Have thinner walls than arteries and less smooth muscles

Capacitance Vessels

• the blood vessels that hold the major portion of theintravascular blood volume
• veins

Walls of arteries and veins

1. Tunica Intima
   
   • the inner layer
   • endothelium (simple squamous)
   • flat so fluid can be exchanged back-and-forth
2. Tunica Media
   
   • The middle layer
   • Layer of smooth muscle
   • Controls the diameter and lumen size
3. Tunica Adventitia
   
   • outer connective tissue layer
   • Contains elastic and collagen fibers

autoregulation

• A reflex adjustment in a small area of a tissue
• varies depending on the needs of the cells in the area

Causes of local vasodilation

• decrease in pH
• increase in carbon dioxide
• decrease in oxygen

composition of blood

• Water and its dissolve solutes (plasma) = 55% of the whole blood volume
• remaining 45% is composed of the cells or formed elements erythrocytes, leukocytes, and thrombocytes

Hematocrit

• Refers to The proportion of cells in blood
• Indicates the viscosity of the blood

plasma

• The clear yellowish fluid remaining after the cells have been removed
• contains:
  • water 92%
  • plasma proteins 7%
  • other solutes 1%
    • Amino acids
    • Carbohydrates
    • Lipids
    • Vitamins
    • Hormones
    • Enzymes
    • Electrolytes
    • Wastes

serum

• Refers to the fluid and solutes remaining after the cells and fibrinogen has been removed

Examples of plasma proteins

• Albumin
• Globulins/Anti-bodies
• fibrinogen

albumin

• Maintains osmotic pressure in the blood

Fibrinogen

• essential for the formation of blood clots

Red bone marrow

• Origination of all blood cells
• found in the flat and irregular bones, ribs, vertebrae, sternum, and pelvis

Erythrocytes or red blood cells

• Biconcave flexible discs
• non-nucleated when mature state
• Contain hemoglobin
• Size and structure are essential for easy passage to small capillaries
• life span = 120 days b/c no nucleus

Erythropoietin

• Originates in the kidney
• Hormone that stimulates erythrocyte production in the red bone marrow

Hemoglobin

• Consists of:
  • the globlin portion
    • two pairs of amino acid chains
  • four heme groups
    • each containing a ferrous iron atom, to which oxygen molecule can attach

Oxyhemoglobin

• A bright red color that distinguishes arterial blood from venous blood

deoxyhemoglobin

• Dark bluish red in color and font and venous blood

Leukopoiesis

• Production of white blood cells
• Stimulated by colony stimulating factors that are produced by cells such as macrophages and T lymphocytes

leukocytes

• Makes up only about 1% of blood volume
• Subdivided into two categories:
  1. Granulocytes
  2. Agranulocytes
• All types develop in differentiate from the original stem cell in bone marrow
• There are five types of leukocytes
  1. Lymphocytes
  2. Neutrophils
  3. Basophils
  4. Eosinophils
  5. Monocytes

Lymphocytes

• Makes up 30 to 40% of the white blood cells

neutrophils

• The most common leukocyte
• Makes up 50 to 60% of White blood cells
• Survive only four days
• The first to respond to any tissue damage And phagocytosis
• Increase in numbers by bacterial affection

Basophils

• Can release histamine and heparin
• Maybe fixed in tissues or wandering

Eosinophils

• Combat the effects of histamine
• Increase by allergic rea ctions and parasitic infections

monocytes

• can enter the tissue to become macrophages

differential count

• Indicates the proportion the specific types of white blood cells in the blood
• Assist in making a diagnosis

Thrombocytes

• Essential part of the blood clotting process
• Not cells
• Non-nucleated

Hemostasis (3 steps)

1. An immediate response of a blood vessel to injury is vasoconstriction of vascular spasm
2. Form a platelet plug in the vessel
3. Coagulation mechanism

Heparin

• an anticoagulant
• Released from basophils or mast cells in the tissues
• Blocks thrombin
• Does not dissolve clots but prevents further growth of the thrombus

Blood type

• Determined by the presence of specific antigens on the cell membranes of erythrocytes

ABO groups

• An inherited characteristic
• Depends on the presence of type A or B antigens

type O blood

• Lack A and B antigens
• are considered universal donors

type A and B blood

• Are universal recipients

RH system

• May cause blood and incompatibility if the mother is Rh negative and the fetus is Rh positive
• Antigen D in plasma membrane = RH positive
• Absence of antigen D = RH negative

Complete blood count (CBC)

diagnostic test for blood

• Includes total red blood cells, white blood cells, platelet count, and morphology (size and shape), a differential count for white blood cells, hemoglobin, and hematocrit values

Leukocytosis

• An increase in white blood cells
• Often associated with inflammation or infection

leukopenia

• Decrease in leukocytes
• Occurs with some viral infections as well as with radiation and chemo therapy

increase in eosinophils

• Common with allergic responses and parasitic infections

morphology

• Observe with blood sMears
• Shows size, shape, uniformity, and maturity of cells
  • Helps to distinguish different types of anemia

Hemoglobin (diagnostic test)

• Amount of hemoglobin per unit volume of blood
• Mean corpuscular volume
  • Indicates the oxygen-carrying capacity of blood
• Mean corpuscular hemoglobin

Reticulocyte Count

• Assessment of bone marrow function

Chemical analysis of the blood

• Determine serum levels of components such as iron, vitamin B12, folic acid, cholesterol, urea, and glucose

Bleeding time (diagnostic test)

• Measures platelet function

prothrombin time (PT) and partial thromboplastin time (PTT)

• Measures function of various factors in coagulation process
• interNational normalized ratio is a standardized version

partial thromboplastin time

• Measures the intrinsic pathway
• PTT... the 2 t's are in(trinsic) a relationship

prothrombin time

• measures the extrinsic pathway

anemia

• A reduction in oxygen transport in the blood due to a decrease in hemoglobin content
• May result from the declining production of the protein, a decrease in the number of erythrocytes, or a combination of these factors
• May be classified by typical cell morphology
• oxygen deficiency leads to:
  • Less energy production and all cells
    • Cell metabolism and reproduction diminished
  • Compensation mechanism to improve the oxygen supply
    • ex:
      • Tachycardia
      • peripheral vasoconstriction
  • General signs of anemia
    • Fatigue, Pallor, dyspnea, and tachycardia
  • Decrease regeneration of epithelial cells

Iron deficiency anemia

• Insufficient iron impairs hemoglobin synthesis
  • Which reduces the amount of oxygen transported in the blood
• Red blood cells are microcytic and hypochromic
• Very common
• Ranges from mild to severe
• Occurs in all age groups
• One in five women is affected
  • Proportion increases for pregnant women
• Frequently a sign of an underlying problem

Etiology of iron deficiency anemia

• Dietary intake of iron may be below the minimum requirement
• Chronic blood loss
• duodenal absorption of iron may be impaired
• Severe liver disease may affect both iron absorption and iron storage

Manifestations of iron deficiency anemia

• pallor of the skin and mucous membranes
• Due to vasoconstriction

• Fatigue,lethargy, and cold intolerance
  • b/c cell metabolism decreased
• Irritability
  • A central nervous system response to hypoxia
• Degenerative changes
  • such as brittle hair, spoon shaped and rigid nails
• Inflammation of oral mucosa and tongue
• Menstrual irregularities
• Delayed healing
• Tachycardia, heart palpitations, dyspnea, syncope

* People who have iron deficiency anemia may have unusual craving for nonfood items such as ice, paint, or starch. This craving is called pica

Diagnostic tests for Iron deficiency anemia

• Laboratory test demonstrate low values of hemoglobin, hematocrit, mean corpuscular volume and mean corpuscular hemoglobin, serum ferritin and serum iron, and transferrin saturation

Treatment for iron deficiency anemia

• Identified underlying cause and resolves if possible
• Consume Iron rich foods or iron supplements

pernicious anemia: vitamin B₁₂ deficiency (megaloblastic anemia)

• The common form of megaloblastic anemia
• Caused by the malabsorption of the vitamin B₁₂
• Iron deficiency may be present as well
• Red blood cells are very large and contain nuclei
• Dietary and sufficiency is a very rare cause
• May be an outcome of surgeries in which the parietal cells are removed or resection of the ileum which is a sight of absorption

Vitamin B₁₂ and nerve cells

• Vitamin B₁₂ is needed for the function and maintenance of neurons
• Deficiency can result in neuropsychiatric symptoms

Manifestations of pernicious anemia

• Tongue is typically in large, red, sore, and shiny
• Decrease in gastric acid leads to digestive discomfort such as nausea and diarrhea
• Tingling or burning sensations in the extremities or loss of coordination and ataxia

Diagnostic tests for pernicious anemia

• Microscopic examination (erythrocytes)
• Bone marrow examination (hyperactive)
• Vitamin B₁₂ serum levels below normal

Treatment for Pernicious Anemia

• Oral supplements are recommended
• Vitamin B₁₂ is administered by injection

Aplastic anemia

• Results from impairment or failure of bone marrow leading to loss of stem cells and pancytopenia
• may be temporary or permanent
• often idiopathic

Pancytopenia

• decreased numbers of erythrocytes, leukocytes, and thrombocytes in the blood.

Hemolytic Anemia

• results from excessive destruction of RBCs
• leads to a low erythrocyte count and low hemoglobin
• causes:
  • genetic defects
  • immune reactions
  • Changes in blood chemistry
  • Presence of toxins in the blood
  • Infections such as malaria
  • Antigen-antibody reaction
    • Incompatible blood transfusion

What term is used to describe a deficit of all types of blood cells?

• Leucopenia
• Neutropenia
• Pancytopenia
• Erythrocytosis

• PANCYTOPENIA

Capillary walls consist of:

• multiple endothelial layers.
• a thick layer of smooth muscle.
• two or three epithelial layers.
• a single endothelial layer

• a single endothelial layer

Individuals with type O blood are considered to be universal donors because their blood:

• contains A and B antibodies.
• contains A and B antigens.
• lacks A and B antibodies.
• lacks A and B antigens.

• lacks A and B antigens.

What causes numbness and tingling in the fingers of individuals with untreated pernicious anemia?

• Persistent hyperbilirubinemia
• Increasing acidosis affecting metabolism
• Vitamin B₁₂ deficit causing peripheral nerve demyelination
• Multiple small vascular occlusions affecting peripheral nerves

• Vitamin B₁₂ deficit causing peripheral nerve demyelination

What is the cause of oral ulcerations and delayed healing occurring with any severe anemia?

• Lack of folic acid for DNA synthesis
• Frequent microinfarcts in the tissues
• Deficit of oxygen for epithelial cell mitosis and metabolism
• Elevated bilirubin levels in blood and body fluids

• Deficit of oxygen for epithelial cell mitosis and metabolism

Why is pernicious anemia treated with injections of vitamin B₁₂?

• An immune reaction in the stomach would destroy the vitamin.
• Digestive enzymes would destroy the vitamin.
• The vitamin irritates the gastric mucosa.
• The ingested vitamin would not be absorbed into the blood.

• The ingested vitamin would not be absorbed into the blood.

Why do vascular occlusions and infarcts occur frequently with sickle cell anemia?

• The red blood cells are abnormally large.
• Increased hemolysis of erythrocytes occurs.
• Erythrocytes change to sickle shape when hypoxia occurs
• HbS is unable to transport oxygen

• Erythrocytes change to sickle shape when hypoxia occurs

In cases of polycythemia vera, blood pressure is elevated as a result of:

• increased blood volume.
• frequent infarcts in the coronary circulation.
• congested spleen and bone marrow.
• increased renin and aldosterone secretions.

• increased blood volume.

In individuals with pernicious anemia, antibodies form to:

• vitamin B₁₂ .
• intrinsic factor or parietal cells.
• mucus-producing glands.
• hydrochloric acid.

• intrinsic factor or parietal cells.

Petechiae and purpura are common signs of:

• excessive hemolysis.
• leucopenia.
• increased bleeding.
• hemoglobin deficit.

• increased bleeding.

Which of the following substances acts as an anticoagulant?

• Prothrombin
• Heparin
• Fibrinogen
• Vitamin K

• Heparin

Why is excessive bleeding a common occurrence with acute leukemia?

• Deficit of calcium ions
• Impaired production of prothrombin and fibrinogen
• Decreased platelets
• Dysfunctional thrombocytes

• Decreased platelets

Multiple myeloma is a malignant tumor involving:

• plasma cells.
• granulocytes
• bone cells.
• lymph nodes.

• plasma cells.

The Reed-Sternberg cell is diagnostic for:

• chronic myeloblastic leukemia.
• Hodgkin’s lymphoma.
• multiple myeloma.
• non-Hodgkin’s lymphoma.

• Hodgkin’s lymphoma.

Which of the following applies to the leukemias?

• Chronic leukemias are more common in older people.
• AML is the most common childhood leukemia.
• Exposure to chemicals is not considered a predisposing factor.
• Lymphoid tissue produces abnormal leukocytes.

• Chronic leukemias are more common in older people.

A high percentage of blast cells in the leukocyte population indicates a poor prognosis for an individual with:

• thalassemia
• acute myelogenous leukemia (AML).
• myelodysplastic syndrome.
• multiple myeloma.

• acute myelogenous leukemia (AML).

Which of the following applies to erythropoietin?

• It is produced by the liver.
• It increases iron absorption for heme production.
• It stimulates production of red blood cells.
• Hypoxia stimulates the red bone marrow to produce erythropoietin.

• It stimulates production of red blood cells.

Microcytic and hypochromic erythrocytes are commonly found as a result of:

• iron deficiency anemia.
• polycythemia
• disseminated intravascular coagulation.
• hemophilia A

• iron deficiency anemia.