Blood and the� Lymphatic and� Immune Systems�

Objectives

• New medical terms (prefixes, roots and suffixes)

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• List the major components, structures and organs of the blood and lymphatic and immune systems and their functions.

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• Describe blood typing systems.

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• Discuss immunity, the immune response and standard precautions.

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• Identify and define:
• Anatomical terms
• Pathology terms
• Diagnostic procedures
• Therapeutic procedures
• Selected medications

Blood

• Function:
• Blood transports gases, nutrients and wastes to all areas of the body either attached to red blood cells or dissolved in the plasma.

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• White blood cells fight infection and disease

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• Platelets initiate the blood clotting process

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• Structures:
• Erythrocytes
• Leukocytes
• Platelets
• Plasma

Anatomy & Physiology

• Average adult has about 5 liters of blood that circulates throughout the body within the blood vessels.

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• Blood is the mixture of cells floating in watery plasma.

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• Formed Elements:
• Erythrocytes (red blood cells)
• Leukocytes (white blood cells)
• Platelets

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• Hematopoiesis: the process of blood cell production in the red bone marrow.

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Plasma

• Liquid Plasma composes about 55% of whole body in an average adult and is 90 – 92% water.

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• 8 – 10% of plasma is dissolved substances, such as (plasma proteins):
• Albumin
• Helps transport fatty substances that cannot dissolve in water.
• Globulins
• 4 types (alpha, beta, beta2 microglobulin and macroglobulin)
• Most common gamma globulin, acts as an antibody
• Fibrinogen
• Blood clotting protein
• Other substances
• Calcium, potassium, sodium, glucose, amino acids and fats
• Waste products, such as: urea and creatinine

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Erythrocytes

• Are Red Blood Cells.
• Are biconcave disks, that are enucleated meaning without a nucleus.
• Appear red due to the hemoglobin, and iron-containing pigment.
• Hemoglobin picks up Oxygen from the lungs and delivers it to the bodies tissues.
• Men have more red blood cells than women.
• Average life-span is 120 days.
• Spleen removes the worn-out and damaged RBCs from circulation.
• A portion of the RBC is disposed of by the liver: Billirubin(waste product)

Leukocytes

• Also known as White Blood Cells (WBCs).
• Provide protection against pathogens
• Such as Bacteria, Viruses and other foreign material.
• Shape (in general)
• Spherical shape with a large nucleus.
• 2 Categories (5 different types)
• Granulocytes (with granules in the cytoplasm)
• Basophils
• Eosinophils
• Neutrophils
• Agranulocytes (without granules in the cytoplasm)
• Monocytes
• Lymphocytes

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Monocyte: engulfs foreign and damaged cells (phagocytosis)

Eosinophil: Destroy parasites and increase during allergic reactions.

Basophil: release histamine and heparin to damaged tissues.

Neutrophil: engulfs foreign and damaged cells (phagocytosis); most numerous of the leukocytes.

Lymphocytes: has several different roles in the immune response.

Platelets

• Also known as Thrombocyte, smallest of the formed elements.
• Formed from shattered large precursor cells (such as blood cell)
• Function – critical in blood clotting
• Hemostasis: agglutinate or clump together in small clusters when a blood vessel is cut or damaged.
• Releases Thromboplastin, which, in the presence of calcium, reacts with prothrombin (clotting protein) to form thrombin.
• Thrombin works to convert fibrinogen to fibrin, which eventually becomes the meshlike blood clot.

New Terminology

• The roots and suffixes for this chapter are on page 178 in your medical terminology book.

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• Make sure you study these as you will see them again!

BREAK – Rest Your Brain

Blood Typing

• Each person’s blood is different due to the presence of antigens or markers on the surface of erythrocytes (RBCs)
• 2 most important subgroups of blood markers:
• ABO system
• 2 possible Red Blood Cell markers (A and B)
• Type A
• Produces Anti-B antibodies (will attack B blood)
• Type B
• Produces Anti-A antibodies (will attack A blood)
• Type AB
• Has both markers and does not contain any antibodies
• Will NOT attack any other type of blood.
• Type O
• Has neither A or B markers.
• Contains both Anti-A and Anti-B antibodies and will attack all other blood types.

• Universal Donor
• Person with type O Neg blood.
• Extreme cases can be given to a person with any of the other blood types.

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• Universal Recipient
• Person with type AB blood.
• Extreme cases can receive any type of blood.

• Rh Factor
• Rh Negative
• Does not have the Rh factor on his or her red blood cells.
• Produces the anti-Rh antibodies. (This could be an issue for a pregnant mother of a Rh positive fetus)
• Can receive only blood with the Rh- factor.

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• Rh Positive
• Has the Rh factor on his or her red blood cells.
• Will not create anti-Rh antibodies.
• Can receive either Rh+ or Rh- Blood.

Other Information Related to the Blood

• Hematology – deals with counting RBCs, white blood cells (WBCs) and platelets.
• Differentiating WBCs on stained blood smears
• Measuring the percentage of RBCs in the blood (hematocrit)
• Determining the oxygen-carrying capacity of the blood (hemoglobin)

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• Complete blood count (CBC) – laboratory procedure most frequently ordered for blood specimens.
• Includes:
• RBC count
• WBC count
• Hemoglobin determination
• Hematocrit determination
• Differential WBC count
• Estimation of platelet numbers
• Red cell indices

Collection of Blood Specimens

• Most blood samples can be taken from capillaries by a finger puncture.

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• If a larger sample is required, it is collected from a vein by venipuncture.

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• For a CBC, a sample is gotten from a vein, collected in a tube with anticoagulant (prevents clotting).

Hematocrit (Hct)

• Definition: measurement of the percentage of packed RBCs in a volume of blood.
• Process of centrifugation is used to separate the cellular elements from the plasma
• Compare the concentration of the RBCs to the total volume of the whole blood sample.
• Normal Hct values vary with gender and age; low of 36% in women to high 52% in men.
• Low Hct values can indicate anemia, or presence of bleeding in the patient.
• High Hct values can be caused by dehydration or a condition such as polycythemia vera.

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Hemaglobin (Hgb)

• Definition: rough measure of the oxygen-carrying capacity of the blood.
• Some places use a color chart; others use the “gold standard”; hemiglobincyanide or cyanmethemoglobin method.
• Blood sample of whole blood diluted with Drabkin’s reagent, which contains cyanide.
• RBCs lyse, releasing hemoglobin, which reacts with the cyanide to form hemiglobincyanide.
• Sample is placed in a colorimeter, and the amount of light absorbed by the sample at a 540-nm wave-length is determined.
• Hemoglobinometer: colormeter that determines the amount of light a sample absorbs due to the chemically modified hemoglobin.

• Normal hemoglobin values vary throughout life.
• Normally quite high at birth, decline during childhood, and increase during the teens until adult levels are reached.
• Values range from low 12 g/dL in women to high 17.5 g/dL in men.
• Factors that affect Hemoglobin levels:
• Age
• Gender
• Diet
• Altitude
• Disease

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• Hemoglobin & Hematocit tests often performed together and are referred to as an “H&H”
• Results: Hemoglobin value x 3+/- 3 should equal the hematocrit value.

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BREAK – Rest Your Brain

Lymphatic and Immune Systems

• Consists of:
• Lymph
• Watery fluid composed of intercellular, or interstitial, fluid, which forms when plasma diffuses into tissue spaces.
• Composed of water, digested nutrients, salts, hormones, O2, CO2, Lymphocytes and metabolic wastes.
• Lymph vessels
• Lymph nodes
• Lymph tissue

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• Functions:
• Collect excess tissue fluid throughout the body and return it to the circulatory system.
• Works with the immune system to form groups of cells the help with invasions of pathogens.
• Help with removal of our own cells that have become diseased.

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Lymphatic Vessels

• These are not in a closed loop like the circulatory system.
• They are one way pipes conducting lymph from the tissues toward the thoracic cavity.
• They start with the small lymphatic capillaries in the tissues
• Excessive fluid enters these to make their trip back to the circulatory system.
• These vessels have valves, to make sure lymph can only move forward.
• Lacteals, pick up digested fats and lipids near the small intestine. When mixed with lipids it is called chyle.
• These vessels drain into 2 large lymphatic ducts:
• Right lymphatic duct
• Drains the R arm and the R side of the head, neck and chest.
• Empties lymph into the R subclavian vein, returns purified lymph to the blood.
• Thoracic duct
• Drains lymph from the rest of the body
• Empties lymph into the L subclavian vein.
• Cisterna chyli, a pouch-like structure, serves as a storage area for purified lymph before it goes to the blood and chyle from the intestinal lacteals.

Lymph Nodes

• Small organs composed of lymphatic tissue located along the route of the lymphatic vessels.
• Also known as, lymph glands:
• Serve to trap and destroy cells from cancerous tumors, pathogens, carbon and dead blood cells.
• Found throughout the body, but concentrate in certain areas.
• In groups or clusters.
• Range from the size of a pinhead to an almond.
• Produce lymphocytes (type of leukocyte, or white blood cell) and antibodies.

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Lymphatic Tissue

• Located throughout the body.
• Tonsils, spleen and thymus are examples.

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• Tonsils:
• Located on either side of the pharynx.
• Filter interstitial fluid and protect against invasion of pathogens through the digestive or respiratory systems.
• 3 pairs of tonsils
• Palatine tonsils, located on each side of the soft palate
• Pharyngeal tonsils, also known as adenoids, located in the nasopharynx
• Lingual tonsils, located on the back of the tongue

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• Spleen:
• Organ located beneath the left side of the diaphragm and in back of the upper part of the abdomen.
• Blood vessels that are spread out into slow moving blood sinuses
• Produces leukocytes and antibodies
• Stores erythrocytes to release due to excessive bleeding
• Phagocytic macrophages line the blood sinuses, to engulf and remove pathogens.
• Destroys thrombocytes (platelets) and recycles iron
• Filters metabolites and wastes from body tissues

• Thymus:
• Mass of lymph tissue located in the center of the upper chest (upper portion of the mediastinum).
• Atrophies (disintegrates) after puberty and is replaced by fat and connective tissue.
• Early on it produces antibodies and manufactures lymphocytes to fight infection.
• It’s function is taken over by the lymph nodes.
• Hormone, Thymosin, changes lymphocytes to T lymphocytes (simply T cells)

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Diseases & Abnormal Conditions

• Adenitis
• Inflammation or infection of the lymph nodes.
• Large amount of pathogens or cancer cells enter the lymph nodes and infect the tissue.
• Signs & Symptoms: fever and swollen, painful nodes
• Treatment: antibiotics and warm, moist compresses.

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• Hodgkin’s Disease
• Chronic, malignant disease of the lymph nodes.
• Most common form of lymphoma
• Signs & Symptoms: painless swelling of the lymph nodes, fever, night sweats, weight loss, fatigue, and pruritus (itching)
• Treatment: chemotherapy and radiation.

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• Lymphangitis
• Inflammation of lymphatic vessels, resulting from an infection in an extremity.
• Signs & Symptoms: characteristic red streak extending up an arm or leg from the source of infection, fever, chills, and tenderness or pain.
• Treatment: antibiotics, rest, elevation of the affected part, and/or warm, moist compresses.

• Splenomegaly
• Enlargement of the spleen
• Can result from: abnormal accumulation of red blood cells, mononucleosis and cirrhosis of the liver
• Signs & Symptoms: swelling and abdominal pain
• Anemia (from increased destruction of red blood cells)
• Leukopenia (low white blood cell count)
• Thrombocytopenia (low thrombocyte count)
• Treatment: severe cases is a splenectomy (surgical removal of the spleen)
• If not treated and it ruptures, intraperitoneal hemorrhage and shock can lead to death.

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• Tonsillitis
• Inflammation or infection of the tonsils.
• Involves the pharyngeal (adenoid) and palatine tonsils.
• Signs & Symptoms: dysphagia (difficulty swallowing), fever, white or yellow spots of exudate on the tonsils, swollen lymph nodes near the mandible.
• Treatment: Antibiotics, warm throat irrigations, rest and analgesics for pain
• Chronic, frequent infections or hypertrophy (enlargement) that causes obstruction are indications for a tonsillectomy.

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Immunity

• Body’s ability to defend itself against pathogens, such as bacteria, viruses, fungi, protozoans, toxins and cancerous tumors.
• 2 Forms:
• Natural immunity (innate immunity) – not specific to a particular disease and does not require prior exposure to the pathogenic agent.
• Ex: Macrophage – high concentration in the lungs and digestive system

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• Acquired immunity (body’s response to a specific pathogen and may be established either passively or actively)
• Passive acquired immunity – when a person receives protective substances produced by another human or animal.
• Ex: antibodies coming from a mother across the placenta or an antitoxin or gamma globulin injection.

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• Active acquired immunity – develops following direct exposure to the pathogenic agent.
• This stimulates the body’s immune response.
• Immunizations or vaccinations are special types.

Chicken Pox

Vaccination

Immune Response

• Antigen – a protein that are different from a person’s own natural protein. Seen as a foreign substance and stimulates the immune response.
• Consists of 2 distinct & different processes:
• Humoral immunity (antibody-mediated immunity)
• Production of B lymphocytes (B cells); which produce antibodies (the protective protein)
• Antigen & Antibody combine to form a antigen-antibody complex which either targets the foreign substance for phagocytosis or prevents the infectious agent from damaging healthy cells.
• Cellular immunity (cell-mediated immunity)
• Production of T cells and natural killer (NK) cells
• These are cytotoxic – they physically attack and destroy pathogenic cells.

Standard Precautions

• Nosocomial infection – when a person acquires an infection in the hospital from another person’s pathogens.

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• These can spread in several ways:
• Cross – infection – when a patient or healthcare worker acquires a pathogen from another patient or healthcare worker.
• Reinfection – when a patient becomes infected again with the same pathogen that brought them to the hospital initially.
• Self – inoculation – when a person becomes infected in a different part of the body by a pathogen from another part of his/her own body (ex: intestinal bacteria that spreads to the urethra).

OSHA - 1987

• Occupational Safety and Health Administration issued mandatory guidelines to ensure that all employees at risk of exposure to body fluids are provided with personal protective equipment.

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• Hand washing techniques
• Wearing gloves
• Non-permeable gown or apron
• Wearing masks/face shields
• Eye protection (sealing area)
• Appropriate cleaning of equipment that has come into contact with body fluids, mucous membranes or non-intact skin.

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