The Cardiovascular System: The Blood Chapter 19 The Cardiovascular System: The Blood

What is blood? Blood is a connective tissue composed of a liquid extracellular matrix called plasma. It has cells and cell fragments dissolved in it. The cardiovascular system is made up of blood, the heart, and blood vessels. Principles of Human Anatomy and Physiology, 11e

Functions of Blood Transportation O2, CO2, metabolic wastes, nutrients, heat & hormones Regulation helps regulate pH through buffers helps regulate body temperature helps regulate water content of cells Protection from disease & loss of blood Hematology is study of blood and blood disorders Principles of Human Anatomy and Physiology, 11e

Physical Characteristics of Blood Thicker than water and therefore flows more slowly than water Feels sticky Temperature of 100.4 degrees F pH 7.4 (7.35-7.45) 8 % of total body weight Blood volume 5 to 6 liters in average male 4 to 5 liters in average female Principles of Human Anatomy and Physiology, 11e

Techniques of Blood Sampling Venipuncture Most common method sample taken from vein with hypodermic needle & syringe Finger or heel stick Used by diabetics to monitor blood sugar Used to test blood of infants Arterial stick: used to determine oxygen levels Principles of Human Anatomy and Physiology, 11e

COMPONENTS OF BLOOD Blood consists of 55% plasma and 45% of cells. Blood plasma consists of 91.5% water and 8.5% solutes. Principal solutes include nutrients, enzymes, hormones, respiratory gases, electrolytes, and waste products. Principles of Human Anatomy and Physiology, 11e

Blood Cells Red blood cells, 40% ( erythrocytes ) White blood cells, 20% ( leukocytes ) neutrophils, eosinophils, basophils lymphocytes = T cells, B cells, and natural killer cells monocytes Platelets, 30% (special cell fragments) Principles of Human Anatomy and Physiology, 11e

Hematocrit Hematocrit is the percentage of total blood volume occupied by RBCs. Anemia not enough RBCs or not enough hemoglobin Can be due to leukemia, iron deficiency, or B12 deficiency Vitamins or injections of iron can treat anemia Polycythemia too many RBCs (over 65%) dehydration, blood loss (including menstruation), blood doping in athletes (common in professional cycling to increase O2 supplies to the blood, muscles, and lungs)

Formation of Blood Cells Most blood cells types need to be continually replaced die within hours, days or weeks process of blood cells formation is hematopoiesis or hemopoiesis In the embryo occurs in yolk sac, liver, spleen, thymus, lymph nodes & red bone marrow In adults occurs only in red marrow of flat bones like sternum, ribs, skull & pelvis and ends of long bones Principles of Human Anatomy and Physiology, 11e

Red Blood Cells or Erythrocytes Contain oxygen-carrying protein hemoglobin that gives blood its red color 1/3 of cell’s weight is hemoglobin Biconcave disk 8 microns in diameter increased surface area/volume ratio flexible shape for narrow passages no nucleus or other organelles Principles of Human Anatomy and Physiology, 11e

RBC Life Cycle RBCs live only 120 days wear out from bending to fit through capillaries no repair possible due to lack of organelles Worn out cells removed by macrophages in spleen & liver Principles of Human Anatomy and Physiology, 11e

Erythropoiesis: Production of RBCs Erythrocyte formation, called erythropoiesis, occurs in adult red bone marrow of certain bones. It takes 1-2 days for a mature red blood cell to be formed and released into the blood stream. Principles of Human Anatomy and Physiology, 11e

Hemoglobin Each RBC has 280 million hemoglobin molecules Each one can bind 4 molecules of oxygen (to the iron at the center of the molecule). Hemoglobin removes CO2 from the blood Hemoglobin also regulates blood pressure by regulating nitric oxide in the blood Principles of Human Anatomy and Physiology, 11e

WHITE BLOOD CELLS Leukocytes (WBCs) have a nucleus but do not have hemoglobin. Granular leukocytes include eosinophils, basophils, and neutrophils based on the straining of the granules. Agranular leukocytes do not have cytoplasmic granules and include the lymphocytes and monocytes. Principles of Human Anatomy and Physiology, 11e

WBC Physiology Less numerous than RBCs 5000 to 10,000 cells per drop of blood 1 WBC for every 700 RBC Leukocytosis is a high white blood cell count microbes, disease, strenuous exercise, anesthesia, cancer or surgery Leukopenia is low white blood cell count radiation, shock or chemotherapy Only 2% of total WBC population is in circulating blood at any given time rest is in lymphatic fluid, skin, lungs, lymph nodes & spleen Principles of Human Anatomy and Physiology, 11e

Neutrophils (Granulocyte) The most abundant WBC 60 to 70% of circulating WBCs First cells to migrate to the site of bacterial infection or cancer formation. Also involved in healing injuries release lysozymes which destroy/digest bacteria release defensin proteins that act like antibiotics & poke holes in bacterial cell walls destroying them release strong oxidants (bleach-like, strong chemicals) that destroy bacteria Principles of Human Anatomy and Physiology, 11e

Eosinophils (Granulocyte) 2 to 4% of circulating WBCs Combat parasites and infections Fight allergies and asthma Principles of Human Anatomy and Physiology, 11e

Basophils (Granulocyte) Less than 1% of circulating WBCs Store histamine and can contribute to allergic reactions Also contain heparin, which prevents blood from clotting too quickly Principles of Human Anatomy and Physiology, 11e

Lymphocyte (Agranulocyte) 20 to 25% of circulating WBCs The main soldiers in the immune system battles B cells destroy bacteria and their toxins turn into plasma cells that produces antibodies T cells attack viruses, fungi, transplanted organs, cancer cells & some bacteria Natural killer cells (NKC) attack many different microbes & some tumor cells destroy foreign invaders by direct attack Principles of Human Anatomy and Physiology, 11e

Monocyte (Agranulocyte) 3 to 8% of circulating WBCs Stored in the spleen Produce macrophages which attack bacteria Destroy microbes and clean up dead tissue following an infection Principles of Human Anatomy and Physiology, 11e

PLATELETS Platelets help stop blood loss from damaged vessels by forming a platelet plug. Their granules also contain chemicals that promote blood clotting. Principles of Human Anatomy and Physiology, 11e

Platelet (Thrombocyte) Anatomy Disc-shaped cell fragment with no nucleus They are produced in the bone marrow and live 5 to 9 days in the blood stream before being recycled by the spleen and liver. Principles of Human Anatomy and Physiology, 11e

Bone Marrow Transplant Bone marrow transplant replaces diseased marrow with healthy marrow. Patient’s diseased marrow is destroyed by cancer or disease. Healthy marrow is supplied by a donor or the patient. It is removed (painfully) by sticking a needle into the hipbone. Risks to recipient include: Infection due to decreased WBC T cells might attack new bone marrow Must take immunosuppressant drugs for life Principles of Human Anatomy and Physiology, 11e

Cord-Blood Transplant Stem cells are taken from the umbilical cord and frozen This method offers several advantages over marrow transplant. Easy to obtain More abundant Are not rejected by patient Don’t transmit infections Can be stored, frozen, forever Principles of Human Anatomy and Physiology, 11e

Hemostasis Stoppage of bleeding in a quick & localized fashion when blood vessels are damaged Prevents hemorrhage (loss of a large amount of blood) Methods utilized vascular spasm platelet plug formation blood clotting Principles of Human Anatomy and Physiology, 11e

Vascular Spasm Damage to blood vessel produces stimulates pain receptors Small blood vessels are contracted which reduces blood flow to the injury site

Platelet Plug Formation Steps in the process (1) platelet adhesion (2) platelet release reaction (3) platelet aggregation Principles of Human Anatomy and Physiology, 11e

Platelet Adhesion Platelets stick to exposed collagen underlying damaged cells in vessel wall Principles of Human Anatomy and Physiology, 11e

Platelet Release Reaction Platelets activated by adhesion Extend projections to make contact with each other This decreases blood flow to injury site Principles of Human Anatomy and Physiology, 11e

Platelet Aggregation Activated platelets stick together and activate new platelets to form a mass called a platelet plug Plug reinforced by fibrin threads formed during clotting process Principles of Human Anatomy and Physiology, 11e

Clot Retraction & Blood Vessel Repair The plug stops the bleeding, then… Edges of damaged vessel are pulled together Fibroblasts & endothelial cells repair the blood vessel Principles of Human Anatomy and Physiology, 11e

Blood Clotting Blood drawn from the body thickens into a gel gel separates into liquid (serum) and a clot of insoluble fibers (fibrin) in which the cells are trapped If clotting occurs inside the body, it is called a thrombosis Having vitamin K in your diet can help prevent blood clotting Principles of Human Anatomy and Physiology, 11e

Blood Groups and Blood Types RBC surfaces are marked by antigens, which determine blood type Principles of Human Anatomy and Physiology, 11e

ABO Blood Groups Blood types in humans are: display only antigen A -- blood type A display only antigen B -- blood type B display both antigens A & B -- blood type AB display neither antigen -- blood type O Type O is the universal donor Type AB is the universal receiver Principles of Human Anatomy and Physiology, 11e

RH blood groups Antigen was discovered in blood of Rhesus monkey People with Rh agglutinogens on RBC surface are Rh+. Most people are Rh + If an Rh - woman is pregnant and the baby is Rh+, the mother’s body may reject the pregnancy; she must take anti-rejection drugs and be closely monitored. Principles of Human Anatomy and Physiology, 11e

DISORDERS: HOMEOSTATIC IMBALANCES Anemia Sickle-cell Hemophilia Disseminated intravascular clotting Acute leukemia chronic leukemia Principles of Human Anatomy and Physiology, 11e

Anemia = Not Enough RBCs Symptoms oxygen-carrying capacity of blood is reduced fatigue, cold intolerance & paleness Types of anemia iron-deficiency =lack of absorption or loss of iron pernicious = lack of intrinsic factor for B12 absorption hemorrhagic = loss of RBCs due to bleeding (ulcer) hemolytic = defects in cell membranes cause rupture thalassemia = hereditary deficiency of hemoglobin aplastic = destruction of bone marrow (radiation/toxins) Principles of Human Anatomy and Physiology, 11e

Sickle-cell Anemia Genetic defect in hemoglobin molecule RBC is deformed sickle-shaped cells rupture easily = causing anemia & clots Found among populations in malaria belt Mediterranean Europe, sub-Saharan Africa & Asia Principles of Human Anatomy and Physiology, 11e

Hemophilia Inherited deficiency of clotting factors bleeding spontaneously or after minor trauma subcutaneous & intramuscular hemorrhaging nosebleeds, blood in urine, articular bleeding & pain Treatment is transfusions of fresh plasma or concentrates of the missing clotting factor Principles of Human Anatomy and Physiology, 11e

Disseminated Intravascular Clotting Life threatening paradoxical presence of blood clotting and bleeding at the same time throughout the whole body Associated with infections, hypoxia, low blood flow rates, trauma, hypotension & hemolysis Clots cause necrosis leading to multisystem organ failure

Leukemia Acute leukemia uncontrolled production of immature leukocytes crowding out of normal red bone marrow cells by production of immature WBC prevents production of RBC & platelets Chronic leukemia accumulation of mature WBC in bloodstream because they do not die Principles of Human Anatomy and Physiology, 11e