Chapter 14

Blood

Functions

• Transportation – Food and oxygen to cells– Waste from cells– Hormones– Heat from the core to the surface

Blood Characteristics

• Plasma = fluid portion of blood. – 55% of the blood’s volume – 90% water, 8% proteins,

and 2% acids and salts.

• Blood Cells:– Erythrocytes – red blood

cells (rbc) (99%)– Leukocytes – white blood

cells (.2%)– Thrombocytes – platelets

(.6 – 1%)

Blood Characteristics Continued

• Blood volume – Varies with age, body type, and sex– Body Fat

• decrease in body fat = increase blood volume. • More oxygen to cells = increase energy

– About 10-12 pints of blood

Blood Cells

• Erythrocytes (Red blood cells)– Appearance

• No nucleus or organelles• Concave shape (donut)• Large surface area to carry oxygen• Great elasticity

– Abnormalities• Sickle cells – crescent shaped RBC’s

– Hemoglobin – molecule in RBC• Contains 4 iron atoms – which allows

oxygen to bind• Men carry more than women• Color of blood depends on

hemoglobin content

Blood Cells Continued• Erythrocytes

– Anemia – the state of having a deficiency of hemoglobin content in RBC’s

– Blood doping – increases RBC’s = increase in hemoglobin = more oxygen to cells

– Formation of RBC’s – Erythoropoiesis• Mature in red bone marrow• Contain reticulocytes – help doctors diagnose how

much blood is being made

– Destruction of RBC’s• Live 3-4 months• Cells lining blood vessels phagocytose RBC’s• Iron is recycled in the liver• Bilirubin is formed = yellow pigment = jaundice

Homeostatic Mechanism – Keeps RBC’s Constant

Normal Red Blood Count

Some Factor (Car Wreck)

Tissue Hypoxia

Increased secretion of erythroprotein by kidney and liver

Decreased # of RBC’s

Hormone

Increased erythropoiesis (rbc production) by red bone marrow

Increased # of RBC’s

Tends to restore

Blood Cells Continued• Leukocytes (White

blood cells)– Appearance

• Five types in body – lymphocytes, neutrophils, eosinophils, monocytes, and basophils

– Function• Fight infection• Phagocytosis – ingest and

digest microbes– Formation

• In red bone marrow or lymphatic tissue

• Life span not known (3-12 days or 3-6 months)

Blood Cells Continued• Platlets

– Appearance• Colorless, irregular

spindles or oval disks– Function

• Hemostasis – stopping of blood flow to area

• Clotting – plugging up ruptured vessels

– Formation• In red bone marrow, lungs,

and spleen• About a 10 day life span

Blood Types• A person’s blood type

depends on the type of antigen on the RBC membrane – Type A – antigen A on RBC– Type B – antigen B on RBC– Type AB – antigen A and B

on RBC (universal recipient)

– Type O – no antigen A or B on RBC (universal donor)

– Rh-factor = Rh antigen on RBC

• Rh-positive = Rh antigen present

• Rh-negative = Rh antigen not present

Blood Types Continued• Antigen – stimulates the formation of

antibodies (identify and neutralize foreign objects) that combine with antigen to clump cells– Danger in blood transfusions– Plasma never contains antibodies against the

antigen present on RBC’s

Blood Types Continued• Anti-Rh antibodies

– No blood usually contains this antibody– Can show up in blood of an Rh-negative

type comes into contact with an Rh-positive type• Transfusions• Pregnant women with Rh-negative blood

– Fetus is Rh-positive (gene from dad)– Blood mixes at birth – mother’s body makes anti-

Rh antibodies (no harm to mother)– During the 2nd pregnancy the antibodies could

attack the fetus and destroy = erythroblastosis fetalis

Blood Types Continued

Blood Coagulation• Mechanism

– Vessel is cut– Bleeding occurs– Platelets aggregate at the site of injury– Formation of a chemical with chemical

fibrinogen– Insoluble fibrin is made and tangles with

RBC which forms the clot– RBC’s give scab a red/brown color

Blood Coagulation Continued

• Opposition of Clotting Mechanism– Smooth surface of blood vessel– Antithrombins – heparin

• No thrombin made – no clot

Blood Coagulation Continued

• Factors that Hasten Clotting– Rough spot on blood vessel lining– Slow blood flow to area – atherosclerosis

• Bed patients must be moved frequently

– Clots seem to grow once started– Clinical method

• Apply gauze – rough surface• Heat massage

http://www.bloodbook.com/type-facts.html

Donating Blood

http://waynesword.palomar.edu/aniblood.htm

Blood Typing

http://nobelprize.org/educational/medicine/landsteiner/index.html

Blood Transfusion Game