The Cardiovascular System

The Blood

• Cells of the body are serviced by 2 fluids:Fluids of the Body

• Nutrients and oxygen diffuse from the blood into the interstitial fluid & then into the cells

• Wastes move in the reverse direction

interstitial fluid• bathes the cells of the

body

blood• composed of plasma

and a variety of cells• transports nutrients

and wastes

Functions of Blood• Transportation

– O2, CO2, metabolic wastes, nutrients, heat & hormones

• Regulation– pH through buffers– body temperature

• coolant properties of water • vasodilatation of surface vessels dump heat

– water content of cells by interactions with dissolved ions and proteins

• Protection from disease & loss of blood

Physical Characteristics of Blood• Denser and more viscous than water • Temperature of 38oC (100.4oF)• pH range 7.35-7.45• 8 % of total body weight (20% of extracellular

fluid)• Blood volume

–5 to 6 liters in average male–4 to 5 liters in average female–hormonal negative feedback systems maintain

constant blood volume and osmotic pressure

Components of Blood

Plasma

Proteins (~7%)

albumins

globulins

fibrinogen

Other Solutes (~1.5%)

electrolytes

nutrients

gases

regulatory substances

waste products

Water (~91%)

Formed Elements of the Blood

Hematocrit• Percentage of total blood volume occupied by red blood

cells– female normal range: 38 - 46% (average of 42%)– male normal range: 40 - 54% (average of 47%)

• Anemia – not enough RBCs or not enough hemoglobin

• Polycythemia– too many RBCs (over 65%)– Dehydration, blood doping in athletes

Hemopoiesis

Red Blood Cells

No nucleus

Biconcave shape

O2 / CO2 transport Provides RBCs their ability to carry oxygen

RBC Lifecycle and Hemoglobin

Control ofErythropoiesis

White Blood CellsCharacteristicsNucleus

lobed

round

Granules

granular

agranular

LymphocyteFunctions: Immune response

Direct attack

Antibodies Characteristics:

Agranular

Round nucleus

Pale blue cytoplasm

MonocyteFunctions:

Phagocytosis

Become macrophages Characteristics:

Large

Agranular

U-shaped nucleus

Neutrophil

Functions:

Phagocytize bacteria

Characteristics:

Nucleus multi-lobed

Inconspicuous granules

Eosinophil

Functions:

Kills parasitic worms

Destroys antigen-antibody complexes

Characteristics:

Nucleus bilobed

Red granules

BasophilFunctions:

Release histamine

Contain heparin

Characteristics:

Nucleus lobed

Blue-purple granules

Emigration of WBCs• WBCs roll along

endothelium, stick to it & squeeze between cells.– adhesion molecules (selectins)

help WBCs stick to endothelium

• displayed near site of injury– molecules (integrins) found on

neutrophils assist in movement through wall

• Neutrophils & macrophages phagocytize bacteria & debris– chemotaxis of both

• kinins from injury site & toxins

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, strenuous exercise, anesthesia 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

Differential WBC Count • Detection of changes in numbers of circulating

WBCs (percentages of each type)– indicates infection, poisoning, leukemia,

chemotherapy, parasites or allergy reaction• Normal WBC counts

– neutrophils 60-70% (up if bacterial infection)– lymphocyte 20-25% (up if viral infection)– monocytes 3 -- 8 % (up if fungal/viral infection)– eosinophil 2 -- 4 % (up if parasite or allergy reaction)– basophil <1% (up if allergy reaction or hypothyroid)

Differential WBC Count

Complete Blood Count• Screens for anemia and infection• Total RBC, WBC & platelet counts; differential

WBC; hematocrit and hemoglobin measurements• Normal hemoglobin range

– infants have 14 to 20 g/100mL of blood– adult females have 12 to 16 g/100mL of blood– adult males have 13.5 to 18g/100mL of blood

Platelets• Myeloid stem cells develop eventually into a

megakaryocyte• Splinters into 2000-3000 fragments• Each fragment enclosed in a piece of plasma

membrane• Disc-shaped with many vesicles but no nucleus• Help stop blood loss by forming platelet plug• Granules contain blood clot promoting chemicals• Short life span – 5-9 days

Summary of Formed Elements

1. Vascular spasm

2. Platelet plug formation

3. Coagulation (clotting)

Hemostasis

- sequence of responses to stop bleeding

Platelet Plug

Formation

Blood Clotting

Clotting Cascade

Clotting Factors

Blood Groups and Blood Types

Blood Groups and Blood Types

ABO Blood Group Interactions

Rh+ has Rh antigen no Rh antibody

Rh- no Rh antigen no Rh antibody

exposure of Rh- to Rh+ will produce antibody

Rh Factor

Hemolytic Disease of the newborn (HDN)

Blood Typing

- reduced oxygen carrying capacity of the blood.1. Insufficient number of RBCs

a. hemorrhagic anemia

b. hemolytic anemia

c. aplastic anemia

2. Decreased hemoglobin content

a. iron-deficiency anemia

b. pernicious anemia

3. Abnormal hemoglobin

a. thalassemia

b. sickle-cell anemia

Anemia

Sickle-Cell Disease (SCD)• Genetic defect in hemoglobin

molecule (Hb-S) that changes 2 amino acids – at very low O2 levels, RBC is

deformed by changes in hemoglobin molecule within the RBC

• sickle-shaped cells rupture easily = causing anemia & clots

• Person with only one sickle cell gene– increased resistance to malaria

because RBC membranes leak K+ & lowered levels of K+ kill the parasite infecting the red blood cells

Hemophilia• Inherited deficiency of clotting factors

– bleeding spontaneously or after minor trauma– subcutaneous & intramuscular hemorrhaging– nosebleeds, blood in urine, articular bleeding & pain

• Hemophilia A lacks factor VIII (males only)– most common

• Hemophilia B lacks factor IX (males only)• Hemophilia C (males & females)

– less severe because alternate clotting activator exists• Treatment is transfusions of fresh plasma or

concentrates of the missing clotting factor

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– classified by type of WBC that is predominant---

monocytic, lymphocytic