Unit 6: Circulatory System

6.1 Blood

Blood Function

Function Effects on Body

Nutritive Transporting nutrient molecules (glucose, amino acids, fatty acids and glycerol) from small intestine or storage sites to tissues

Respiratory Transporting oxygen from the lungs to the tissues and carbon dioxide from the tissue to the lungs

Excretory Transporting waste products (lactic acid, urea and creatinine) from cells to excretory organs

Regulatory Transporting hormones and other chemical substances that control the proper functioning of many organs.Circulating excess heat to the body surfaces and to the lungs, through which it is lost (controls body temperature).Maintains water balance and a constant environment for tissue cells.

Protective Circulating antibodies and defensive cells throughout the body to combat infection and disease

Blood Composition

• Blood is made up of the following major components:• Plasma

• Cellular Elements:• Erythrocytes

• Leukocytes

• Thrombocytes

Blood Plasma

• Composes about half of blood volume

• Made up of the following substances in solution:1. Water – makes up about 90% of plasma

2. Blood proteins – hemoglobin (oxygen)

3. Plasma proteins – fibrinogen (blood clotting), serum albumin (osmotic pressure), serum globulin (antibodies and coagulation)

Blood Plasma

• Composes about half of blood volume

• Made up of the following substances in solution:4. Nutrients – absorbed from digestive tract (glucose,

fatty acids, cholesterol, amino acids)

5. Electrolytes – come from food (sodium chloride and potassium)

6. Hormones, vitamins, enzymes – control chemical reactions (very small amounts)

7. Metabolic waste products – come from cellular functions to go to excretory organs

Erythrocytes

• Erythrocytes are commonly known as red blood cells (RBCs)

• Only live about 120 days due to the lack of a nucleus

• Hemoglobin pigment in erythrocytes gives the red color• A single erythrocyte contains

several million molecules of hemoglobin

• Vital in carrying oxygen to tissues and some carbon dioxide away from tissues.

• Normal hemoglobin count (per 100cc):

• Males: 14-18 gm• Females: 12-16 gm

Erythrocyte Function

• In lungs, erythrocytes pick up oxygen from air breathed in• Oxygen combines with hemoglobin to form the

molecule oxyhemoglobin

• The oxygen-rich erythrocytes travel to the tissues and the oxygen is released

• In tissues, erythrocytes pick up carbon dioxide

• Erythrocytes circle back to the lungs to release carbon dioxide and pick up more oxygen

Erythropoiesis

• Creation of red blood cells• Occurs in bone marrow of

all bones, until adolescence.

• As one grows older, red blood cells are formed in short and flat bones

• Erythrocytes come from stem cells in red bone marrow (hemocytoblasts)• As hemocytoblasts

develop, they lose their nucleus and cytoplasmic organelles. Becomes smaller and gains hemoglobin.

Hemolysis

• Rupturing (bursting) of red blood cells• Can occur due to a

blood transfusion or other disease process

Leukocytes

• Leukocytes are commonly known as white blood cells (WBCs)• Larger than

erythrocytes• Have a granular,

agranular, translucent and ameboid shape

• Manufactured in red bone marrow and lymphatic tissue

Types of Leukocytes

• Granulocytes (granular leukocytes): synthesized in red bone marrow by myeloblasts; destroyed as they age (from bacterial destruction); most only live a few days• Neutrophils (polymorphonuclear leukocytes):

phagocytize bacteria with lysosomal enzymes• Eosinophils: phagocytize antibody-antigen reactions;

increase greatly in allergic reactions, malaria and worm infestations

• Basophils: perform phagocytosis; increases during chronic inflammation and healing from infection; produce histamine (vasodilator) and heparin (coagulant)

Types of Leukocytes

• Agranulocytes:• Lymphocytes: life spans a few days to several years; help

body by synthesizing and releasing antibody molecules and protect against cancer cell formation• B-lymphocytes: synthesized in bone marrow

• T-lymphocytes: synthesized in thymus gland

• Others are formed in lymph nodes and spleen

• Monocytes: formed in bone marrow and spleen; assist in phagocytosis; can leave blood and attach to tissues

Inflammation

• Occurs when tissues are subjected to a chemical (heat) or physical (cut) trauma

• Invasion of pathogens (bacteria, fungi, protozoa, viruses) can also cause inflammation

• Characteristics are redness, local heat, swelling and pain

Inflammation Reaction

1. Histamine released from basophils increases blood flow to the injured area

2. Neutrophils begin phagocytosis of pathogen

• In most inflammations, a cream-colored liquid (pus) forms. Pus is a combination of dead tissue, dead and living bacteria, dead leukocytes and blood plasma.

• If the damaged area is below the epidermis, an abcess(pus-filled cavity) forms. If it is on the skin or mucous surface, it is called an ulcer.

Thrombocytes

• Thrombocytes are commonly called blood platelets.• Ovoid-shaped structures synthesized by

megakaryocytes in red bone marrow.• Thrombocytes are NOT cells but fragments of the

megakaryocytes cytoplasm.• Function in the initiation of the blood clotting process

(coagulation).• Thrombocytes produce sticky projecting structures

when introduced to a wounded area.• Release serotonin which causes blood vessel to spasm

and narrow decreasing the amount of blood flow to the area.

Coagulation

• “Blood clotting”

• When a blood vessel or tissue is injured, platelets and tissue release thromboplastin (plasma protein).• Converts prothrombin to

thrombin

• Thrombin changes fibrinogen into fibrin• Traps RBC, platelets and

plasma creating a blood clot

• As serum oozes out of cut, it dries and a crust (scab) forms.

• In order for coagulation to occur properly:• Two anticoagulants must be

neutralized to allow coagulation

• The clotting time for humans is from 5-15 minutes.

Once Upon a Time…The Tiny Platelets• Part 1

• Part 2

• Part 3

Blood Types

• Four types of blood: A, B, AB, O

• Inherited from parents and determined by the presence (or absence) of blood protein antigens on the surface of the red blood cell• Type A: presence of A antigen

• Type B: presence of B antigen

• Type AB: presence of A and B antigen

• Type O: absence of A and B antigen

Rh Factor in Blood

• Human red blood cells also contain Rh antigen (found in the Rhesus monkey)• Found on the surface of red blood cells

• Someone containing the Rh antigen is said to be “Rh positive (Rh+)”

• Someone not containing the Rh antigen is said to be “Rh negative (Rh-)”

Blood Types

Blood Type Compatibility

Blood Typing Problems – Handout

Concept Map: Blood – Handout

• WORD BANK:• Red blood cells• Homeostasis• Albumins• biconcave disc• bone marrow• transport nutrients• Hemoglobin• Monocytes• defend against diseases• Plasma• Leukocytes

• Spleen• Phagocytes• inflammatory reaction• Water• Platelets• Hematopoeisis• Eosinophils• Oxygen• Nucleus• Hemostasis• Globulins• Antibodies

Blood Disorders

• Sickle cell anemia• Causes: genetic disorder

that causes blood cells to become sickle shaped instead of oval shaped

• Symptoms: pain, lethargy, lifelong anemia (low RBC count), organ failure, stroke

• Treatment: bone marrow transplant, medication to reduce pain and prevent complications, blood transfusions

Blood Disorders

• Hemophilia• Causes: disorder that causes

the blood not to clot• Symptoms:

unexplained/excessive bleeding, large/deep bruises, blood in urine/stool, nosebleeds without a cause

• Treatment: blood transfusions, gene replacement for clotting factor

• Believed that Queen Victoria was the original carrier of the disease

Blood Disorders

• Leukemia• Causes: cancer of the

blood due to the overproduction of WBC

• Symptoms: fatigue/weakness, frequent infections, losing weight without trying, swollen lymph nodes, easy bleeding/bruising

• Treatment: bone marrow transplants, chemotherapy, radiation

Blood Disorders

• Mononucleosis: “mono” or “kissing disease”• Causes: infection caused by

Epstein-Barr virus (EBV); increase in lymphocytes in the bloodstream

• Symptoms: fatigue, loss of appetite, headache, sore and red throat, chills, fever, aches, swollen and red tonsils, swollen lymph nodes, cough

• Treatment: bed rest, good nutrition, fluids (antibiotics don’t work against viruses)

Blood Disorders

• Septicemia: “sepsis” or “blood poisoning”• Causes: infection in the

bloodstream• Symptoms: body

temperature above 101 F or below 96.8 F, heart rate greater than 90 beats per minute, respiratory rate higher than 20 breaths per minute

• Treatment: antibiotics

Blood Crossword – Handout

Blood Feedback Loop – Handout