Chapter 6 Cardiovascular System: Blood. What are the functions of blood? Transportation: oxygen,...

Chapter 6

Cardiovascular

System: Blood

What are the functions of blood?

• Transportation: oxygen, nutrients, wastes, carbon dioxide and hormones

• Defense: against invasion by pathogens

• Regulatory functions: body temperature, water-salt balance and body pH

6.1 Blood: An overview

What is the composition of blood?

• Formed elements: produced in bone marrow– Red blood cells/erythrocytes (RBC)– White blood cells/leukocytes (WBC)– Platelets

• Plasma: – 91% water and 9% salts (ions) and organic molecules

6.1 Blood: An overview

The structure of red blood cells is important to their function

• Lack a nucleus and few organelles

• Biconcave shape increases surface area

• Contain about 280 million hemoglobin molecules that bind 3 molecules of O2 each

6.2 Blood: Red blood cells and transport of oxygen

Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.

a: © Andrew Syred/Photo Researchers, Inc.; c: © Lennart Nilsson, Behold Man, Little Brown and Company, Boston

a. Red blood cells b. Hemoglobin molecule c. Blood capillary

helical shapeof the polypeptidemolecule

ironhemegroup

capillary

Production of red blood cells

• Produced in the bone marrow

• Lifespan of about 120 days

• Erythropoietin (EPO) is excreted by kidney cells and moves to red marrow when oxygen levels are low

• Old cells are destroyed by the liver and spleen



Normal O2

blood level

2. Kidney increaseproduction oferythropoietin

1. Low O2

blood level

3. Stem cells increasered blood cellproduction

4. O2 blood levelreturns to normal

What is blood doping?• Any method of increasing the number of RBC’s

to increase athletic performance

• EPO is injected into a person months prior to an athletic event

• Is thought to be able to cause death due to thickening of blood that leads to a heart attack


What disorders involve RBC’s?• Anemia – a condition resulting from too few

RBC’s or hemoglobin that causes a run-down feeling

• Sickle-cell anemia – genetic disease that causes RBC’s to be sickle shaped that tend to rupture

• Hemolytic disease of the newborn – a condition with incompatible blood types that leads to rupturing of blood cells in a baby before and continuing after birth


White blood cells

• Derived from red bone marrow• Large blood cells that have a nucleus• Production is regulated by colony-stimulating

factor (CSF)• Can be found in the blood as well as in tissues• Fight infection and an important part of the

immune system• Some live days and others live months or years

6.3 White blood cells and defense against disease

What disorders involve WBC’s?

• Severe combined immunodeficiency disease (SCID) – an inherited disease in which stem cells of WBC’s lack an enzyme that allows them to fight any infection

• Leukemia – a groups of cancers that affect white blood cells in which cells proliferate without control

• Infectious mononucleosis – also known as the “kissing disease” occurs when the Epstein-Barr virus (EBV) infects lymphocytes resulting in fatigue, sore throat and swollen lymph nodes

6.3 White blood cells and defense against disease

Platelets• Cell fragments

• About 200 billion are made per day

• Function in blood clotting

6.4 Platelets and blood clotting

How do platelets clot blood?6.4 Platelets and blood clotting


b: © Eye of Science/Photo Researchers, Inc.

b. Blood clot 4,400

1. Blood vessel is punctured.

2. Platelets congregate and form a plug.

3. Platelets and damaged tissuecells release prothrombinactivator, which initiates acascade of enzymatic reactions.

4. Fibrin threads form and trap red blood cells.

Prothrombin activator

Prothrombin

Ca2+

Ca2+

Thrombin

Fibrinogen Fibrin threads

a. Blood-clotting process

fibrin threads

red blood cell

Step one: Blood vessel is punctured

Step two: Platelets form plug

Step three: Platelets release proteins that cause fibrin threads to form

Step four: Fibrin thread trap red blood cells

What disorders involve platelets?

• Thromboembolism – when a clot forms and breaks off from its site of origin and plugs another vessel

• Thrombophilia - when blood naturally clots to much

• Hemophilia – a genetic disorder that results in a deficiency of a clotting factor so that when a person damages a blood vessel they are unable to properly clot their blood both internally and externally

• Von Willebrands disease – deficiency in the factor that helps platelets clot

6.4 Platelets and blood clotting

Terminology to help understand ABO blood typing?

• Antigen - a foreign substance, often a polysaccharide or a protein, that stimulates an immune response

• Antibody – proteins made in response to an antigen in the body and bind to that antigen

• Blood transfusion – transfer of blood from one individual into another individual

6.5 Blood typing and transfusions

Visualizing how hemolytic disease of the newborn happens?



a. Fetal Rh-positive red blood cells leak across placenta intomother's bloodstream.

b. Mother forms anti-Rh antibodies that cross the placenta and attackfetal Rh-positive red blood cells.

Rh-negative redblood cell of mother

Rh-positivered blood cell

of fetus

anti-Rhantibody

blood of mother blood of mother

How can hemolytic disease of the newborn be prevented?

• Rh- women are given an injection of anti-Rh antibodies no later than 72 hours after birth to an Rh+ baby

• These antibodies attack fetal red blood cells in the mother before the mother’s immune system can make antibodies

• This will have to be repeated if an Rh- mother has another Rh+ baby in case she has later pregnancies


How does the heart, blood vessels and blood work with other systems to maintain homeostasis?

6.6 Homeostasis


Cardiovascular System

Nervous System

Blood vessels transport hormones fromglands to their target organs. The Hormone epinephrine increases blood pressure; other hormones help regulate blood volume and blood cell formation.

Endocrine System

Respiratory System

Muscular System Skeletal System

Urinary System

Digestive System

Lymphatic System

All systems of the body work with thecardiovascular system to maintainhomeostasis. These systems inparticular are especially noteworthy.

Heart pumps the blood. Blood vesselstransport oxygen and nutrients to the cellsof all the organs and transports wastes awayfrom them. The blood clots to prevent bloodloss. The cardiovascular system alsospecifically helps the other systems asmentioned below.

Blood vessels deliver nutrients from thedigestive tract to the cells. The digestive tractprovides the molecules needed for plasmaprotein formation and blood cell formation.The digestive system absorbs the waterneeded to maintain blood pressure and theCa2+ needed for blood clotting.

Blood vessels transport wastes to be excreted.Kidneys excrete wastes and help regulatethe water-salt balance necessary to maintainblood volume and pressure and help regulatethe acid-base balance of the blood.

Muscle contraction keeps blood movingthrough the heart and in the blood vessels,particularly the veins.

Nerves help regulate the contraction of theheart and the constriction/dilation of bloodvessels.

Blood vessels transport gases to and from lungs. Gas exchange in lungs Supplies oxygen and rids the body of carbon dioxide, helping to regulate the acid-base balance of blood. Breathing aids venous return.

Capillaries are the source of tissue fluid,which becomes lymph. The lymphaticsystem helps maintain blood volume bycollecting excess tissue fluid (i.e., lymph), and returning it via lymphatic vessels to thecardiovascular veins.

The rib cage protects the heart, red bonemarrow produces blood cells, and bonesstore Ca2 ; for blood clotting.

Chapter 6 Cardiovascular System: Blood. What are the functions of blood? Transportation: oxygen,...

Documents

Transcript of Chapter 6 Cardiovascular System: Blood. What are the functions of blood? Transportation: oxygen,...