Blood

Properties of blood

• Viscous

• Temp 100.4F

• pH range 7.35- 7.45 (alkaline)

• 5-6 L males; 4-5 L females

• 8% body weight

Functions of Blood• Transport (Co2, O2, waste, nutrients,

hormones)

• Maintenance of body temperature, pH, H2O content cells

• Protection against foreign substances; antibodies

• Clot formation

Plasma Contents• Liquid part of blood.

– 91% water ; 9 % solutes• Proteins

– Albumins: made by liver; viscosity, osmotic pressure

– Globulins: Transports other molecules– Fibrinogen: blood clotting

• Ions: involved in osmosis, membrane potentials, and acid-base balance

• Nutrients: glucose, amino acids, cholesterol, vitamins

Plasma Contents Cont’d.

• Waste Products: – Urea, uric acid, creatinine, ammonia salts– Bilirubin– Lactic acid– Gases: oxygen, carbon dioxide, and nitrogen

• Regulatory substances: hormones, enzymes

Formed Elements

RBC

WBC

Platelet (megakaryocyte)

Hematopoiesis

Hematopoiesis (in bone marrow)

White Blood Cells (WBCs)• Leukocytes

• Protect body against microorganisms and remove dead cells and debris

• Movements– Ameboid: pseudopods– Diapedesis: cells move through blood

vessels– Chemotaxis: attraction to and movement

toward foreign materials or damaged cells

White Blood Cells1% normal blood

Agranular V. Granular

Neutrophils

• Lobed nuclei connected by filaments

• 50-70% WBCs• Last 1-2 days• Move into tissues and

phagocytize substances• Fight normal infections

• bacterial

• PUS!

Eosinophils

• Bi-lobed nucleus; granules stain red (“eos” = dawn)

• Enter tissues during inflammatory response

• 1-4% WBCs– Parasitic infections;

Allergic response

Basophils

• Indistinct lobed nucleus

• Less than 1% WBCs• Release histamine

(vasodilation) and heparin (anticoagulant)

• Inflammatory response & allergic reactions

Monocytes

• Kidney shaped or round nucleus

• 2-8% WBCs• Become macrophages• Macrophages found in

tissues (spleen)• Osteoclasts & Microglia• Fight chronic infections,

tumors, remove old tissue• Present antigens to

lymphocytes

Lymphocytes• Big, round nucleus• 25-40% WBCs• B-cells: produced in

Bone marrow– Produce antibodies

• T-cells: produced in marrow and migrate to Thymus to mature

• IMMUNE SYSTEMAntigen: foreign proteinAntibody: binds to antigen and causes death or removal by WBC

The Immune System is the Third Line of Defense Against Infection

Components of the immune system

Lymphocytes• B Cells

– Produced/ mature in red marrow; then move to lymph ts.

– Produce antibodies that battle bacteria and some viruses

• T Cells– Mature in Thymus gland– Directly contact antigens– Affect mostly abnormal

body cells (cancerous/ virus infected, transplant ts.)

Innate Immunity (non-specific) : Immunity an organism is born with Genetically determined All antigens attacked equally by neutrophils,

macrophages, basophils, eosinophils Skin, saliva, tears, stomach acids, mucus

Acquired Immunity (specific): Immunity that an organism develops during lifetime after exposure to antigen

Not genetically determined

Based on immune system recognizing, remembering, and responding to antigens

Active body exposed to antigen (naturally or thru vaccine) and generates an immune response

Passive antibodies (antiserum) introduced to body; no immune response c=generated; short-lived

Red Blood Cells (RBCs)• Erythrocytes• 95% “formed elements”• Biconcave discs…

WHY?• Anucleate• Antigens on surface

determine blood type

Erythropoiesis• Lifespan= 120 days• Spleen and liver “clean-up”

– bilirubin• Takes 4 days to make one RBC; 2.5 million made each second!• Reticulocytes: immature RBCs• Erythropoietin: hormone stimulates RBC production; produced

by kidneys in response to low blood O2 levels

Erythrocyte function: Transport

• Oxygen from lungs to tissues: 98.5% attached to hemoglobin; 1.5% dissolved in plasma

• Carbon dioxide from tissues to lungs. – 7% dissolved in plasma– 23% in combination with hemoglobin– 70% transported as bicarbonate ions

produced as a result of combination of H2O and CO2 because of enzyme carbonic anhydrase found within RBCs

Hemoglobin

• Hemoglobin (Hgb/ Hb)– Heme (iron): Fe + Protein (globin)

– Each Hgb carries 4 O2 molecules (oxyhemoglobin)

– Each RBC carries 250 million Hgb molecules…

Regulation of blood pHMore H+ causes blood to be more acidicFewer H+ causes blood to be less acidic70% of carbon dioxide (CO2) in blood is dissolved in plasma forming carbonic acid (H2CO3)

H2CO3 is then dissociated into HCO3- and H+

H2CO3 acts as a hydrogen ion donor (acid)

HCO3- is the hydrogen ion acceptor (base)

HCO3- /CO2 buffer system is extremely important because it can be rapidly

readjusted in alkalosis and acidosis

AcidosisToo Much CO2 or Too Little HCO3

- Will Cause Acidosis

The balance will swing toward a low pH (acidosis) if 1. CO2 is raised hypoventilation (pneumonia, emphysema)

2. HCO3

- lowered Metabolic conditions such as ketoacidosis caused by excess fat metabolism (diabetes mellitus) will lower bicarbonate

Symptoms may include:ConfusionEasy fatigueLethargyShortness of breathSleepinessCompensation for acidosis: Remove CO2: occurs first because lungs work faster than kidneys Add HCO3

-

AlkalosisToo little CO2 or Too much HCO3 Will Cause AlkalosisThe balance will swing toward a higher pH (alkalosis) if

1. CO2 is lowered (hyperventilation)

2. Bicarbonate is raised (Vomiting reduces stomach acid) Alkalosis is less common than acidosis

Symptoms may include:Deep, rapid breathingDizziness, agitation; seizures; Compensation for alkalosis: Add CO2: occurs first because lungs work faster than kidneys Remove HCO3

-

ABO Blood Groups

Rh antigen: another antigen; positive (+) blood has it, negative (-) does not

Transfusions

• Donor: gives blood

• Recipient: receives blood

• We have antibodies against antigens that we do not have!

Red Cross Facts

Thrombocytes

• Arise from megakaryocytes; anucleate

• Form platelet plugs (small vessels)

• Form clots (larger wounds)

Hemostasis: “Stop Bleeding”!

1. Vasoconstriction: reduces blood flow

2. Platelet plug formation: platelets attracted to exposed proteins from damaged tissue, attracted to more platelets... (Positive feedback!)

3. Coagulation: thrombin (enzyme) activates fibrinogens (plasma proteins) when tissue is damaged… clotting factors

4. Dissolution: after epithelial cells rebuild, WBCs destroy clot

Blood “Thinners”

Heparin inhibits thrombin; isolated from pigs and cows; must be injected; short-lived

Coumadin: inhibits processing of vitamin K (needed for liver synthesis of clotting factors); taken orally

Aspirin: inhibits platelet activation

Coagulation Factors

• Plasma proteins

• 13 clotting factors (+ 4 platelet factors)

• Many made in liver with aid of Vitamin K

Clotting Disorders

• Immune Thrombocytopenia (ITP)– autoimmune

• Von Willebrand– Most common bleeding

disorder

• Hemophilia A: missing Factor VIII– 80% Hemophilia

• Hemophilia B: missing Factor IX

Anemias: usually refers to a condition in

which your blood has a lower than normal number of red blood cells. This condition also can occur if your red blood cells don't contain enough hemoglobin

Anemia has three main causes: blood loss, lack of red blood cell production, or high rates of red blood cell destruction.

• Iron deficient

• Pernicious

• Aplastic

• Hemolytic

Iron-deficiency anemia •Lack of iron usually due to blood loss, poor diet, or an inability to absorb enough iron from foods

•Microcytic RBCs; low hemoglobin values

•Symptoms fatigue, shortness of breath, chest pain, dizziness, pallor. (Severe iron-deficiency anemia can lead to heart problems, infections, problems with growth and development in children, and other complications.)

•People at highest risk for iron-deficiency anemia include infants and young children, women, and adults who have internal bleeding.

Hemolytic Anemia: is due to high rates of red blood cell destruction. When blood cells die, the body's bone marrow makes more blood cells to replace them. However, in hemolytic anemia, the bone marrow can't make red blood cells fast enough to meet the body's needs.

Inherited forms:•Sickle Cell Anemia: a serious, inherited disease. In this disease, the body makes abnormal hemoglobin. This causes the red blood cells to have a sickle, or "C," shape.

– Sickle cells don't last as long as healthy red blood cells. They usually die after only about 10 to 20 days. The bone marrow can't make new red blood cells fast enough to replace the dying ones.

– Sickle cell anemia mainly affects people of African descent.

•Thalassemias: inherited blood disorders in which the body doesn't make enough of certain types of hemoglobin. This causes the body to make fewer healthy red blood cells than normal.

– most often affect people of Southeast Asian, Indian, Chinese, Filipino, Mediterranean, or African origin or descent.

Acquired forms:Autoimmune hemolytic anemia (AIHA). In this condition, your immune system makes antibodies (proteins) that attack your red blood cells. Why this happens isn't known. AIHA accounts for half of all cases of hemolytic anemia. AIHA may come on very quickly and become serious. It's most common in people older than 40.

Rh-Incompatibility: WBC’s of Rh negative mothers can cause hemolytic in second child

Acquired aplastic anemia: most common, sometimes temporary. In many people the cause is unknown. Some research suggests that stem cell damage may occur because the body's immune system attacks its own cells by mistake.

Inherited aplastic anemia (rare): Certain inherited conditions can damage the stem cells Causes: •Toxins, such as pesticides, arsenic, and benzene. •Radiation and chemotherapy (treatments for cancer). •Infectious diseases, such as hepatitis, Epstein-Barr virus, cytomegalovirus, parvovirus, HIV. •Autoimmune disorders, such as lupus and rheumatoid arthritis. •Pregnancy. (Aplastic anemia that occurs during pregnancy often goes away after delivery.) •Sometimes, cancer from another part of the body can spread to the bone and cause aplastic anemia.

Symptoms irregular heartbeats called arrhythmias, an enlarged heart, heart failure, infections, and bleeding. Severe aplastic anemia can even cause death.

Aplastic anemia is a blood disorder in which the body's bone

marrow doesn't make enough new blood cells. This is because the bone marrow's stem cells are damaged. (Aplastic anemia also is called bone marrow failure.)

Polycythemia• Hematocrit over 48% (women) or 52% (men)• The extra red blood cells make your blood

thicker than normal leading poor circulation and possible to heart attack and stroke

• Symptoms headaches, dizziness, itching, and vision problems, such as blurred or double vision, angina (chest pain), and heart failure

• Causes of Primary polycythemia: DNA mutation causes excess RBC production;

• Causes of Secondary polycythemia: living at high altitudes as a response to lower oxygen levels; hypoxic diseases, radiation exposure

Normal blood

Polycythemia vera

Erythrocytosis an excess of erythrocytes, (RBCs)

Hemochromatosis: iron builds up in body

Excess iron can is toxic to organs and causes organ failure. Iron especially builds up in the•liver (enlarged liver, liver failure, liver cancer, or cirrhosis )•heart (irregular heartbeats called arrhythmias and heart failure)•pancreas (diabetes)

Primary hemochromatosis: recessive genetic disorder; one of the most common genetic diseases in the United States; most common in Caucasians of Northern European descent; less common in African Americans, Hispanics, Asians, and American Indians; more common in men than in women; older people are more likely to develop the disease than younger people.

Secondary hemochromatosis : can be caused by thalassemias, other anemias, chronic alcoholism

** Certain factors can affect the severity of the disease. For example, a high intake of vitamin C can make hemochromatosis worse. This is because vitamin C helps your body absorb iron from food**

Leukocytosis is an increased number of leukocytes

A high white blood cell count usually indicates: •An increased production of white blood cells to fight an infection•A reaction to a drug that enhances white blood cell production•A disease of bone marrow, causing abnormally high production of white blood cells•An immune system disorder that increases white blood cell production

Specific causes of high white blood cell count include: •Leukemia * Measles•Myelofibrosis * Other bacterial infections•Other viral infections * Polycythemia vera•Rheumatoid arthritis * Smoking•Tuberculosis * Whooping cough•Stress * Tissue damage, such as from burn•Allergy, especially severe allergic reactions•Drugs, such as corticosteroids and epinephrine

Leukopenia – low wbc countCauses:•Viral infections that temporarily disrupt bone marrow function•Congenital disorders characterized by diminished bone marrow function•Cancer or other diseases that damage bone marrow•Autoimmune disorders that destroy white blood cells or bone marrow cells•Overwhelming infections that use up white blood cells faster than they can be produced•Drugs that destroy white blood cells or damage bone marrow

Specific causes of low white blood cell count include: •Aplastic anemia * Leukemia•Lupus-autoimmune disorders * Other congenital disorders•Parasitic diseases * Radiation therapy•Rheumatoid arthritis * Vitamin deficiencies•Certain medications, such as antibiotics and diuretics * Chemotherapy•HIV/AIDS/ * Hypersplenism•Hyperthyroidism (overactive thyroid)Infectious diseases•Kostmann's syndrome, a congenital disorder involving low neutrophil production

Leukemia

• Bone marrow produces a high number of abnormal WBCs• Chronic: progresses slowly Vs. Acute: progresses quickly• Type of leukemia depends on what type bone marrow cell affected

(myeloid: early granular WBC or lymphoid: early lymphocyte)– Some types are more common in children or adults

• Symptoms Weakness, Fatigue, Anemia, Frequent infections or fever, Weight loss and/or loss of appetite, Increased bruising or bleeding from wounds, Bone pain or joint pains caused by the spread of malignant cells to the surface of the bone or into the joint from the marrow cavity, Enlarged lymph nodes, liver and/or spleen

• Treatment includes chemotherapy, radiation, medication GOAL= remission

Chronic lymphocytic leukemia (CLL): mostly adultsChronic myeloid leukemia (CML): mostly adults

Acute lymphocytic (lymphoblastic) leukemia (ALL): most common in childremAcute myeloid leukemia (AML): both adults and children