Chapter 11 -Blood

“ I vant to suck yur blood”Count Dracula

Functions of Blood

1) transport-dissolved gases, nutrients, hormones and metabolic waste

2) Regulate pH & ions, ex. calcium, potassium, lactate acid control

3) Restrict fluid loss at injury site, ie. blood clot4) Defend against toxins and pathogens. White

blood cells (WBCs) and antibodies5) Stabilize body temp.

Blood Composition

• Chart- page 367• 55% plasma ( leave space for next slide)• 45% formed elements

Plasma• 92% water!! Excellent for transporting dissolved

molecules and heat• 7% Plasma proteins-

– Albumin and Globulin for transport– Fibrinogen for clotting– Regulatory proteins- enzymes, hormones

• 1% other solutes (dissolved stuff)- – Electrolytes: Na+ , K+, Cl-, etc.– Organic nutrients ( used for energy & building stuff):

Fatty acids, glucose, amino acids, etc.– Organic waste: Urea, bilirubin ( broken down RBCs)

Formed elements

• 99.9% RBCs!!• 0.1% WBCs and platelets

Blood Trivia

• Blood Temp: 100.4o F (Hot Blooded by Foreigner!)

• Viscosity- 5 times more resistant to flow than water ( “blood is thicker than water”)

• pH of 7.2-7.4 (slightly alkaline)

RBCs• As adults, hemopoiesis occurs in red bone

marrow.• As fetus, RBC formation also occurs in liver

and spleen• Hematocrit- % by volume of formed elements

in whole blood, found by centrifuging• 46% in men, 42% in women- why?

RBC Anatomy/Physiology• Loses many cellular components upon maturity:

nucleus, DNA, mitochondria• Shaped like a donut, contains many molecules of

hemoglobin• Each hemoglobin contains 4 pigment groups

called “heme” groups• Each heme group holds an iron ion that can form

a weak bond with an O2, lots of CO2 causes the bond to break and release O2

• However, CO has a much higher affinity to hemoglobin than O2!

• Anemia- blood with low ability to carry O2

– Symptoms: lack of energy, premature muscle fatigue, weakness

• RBC lifespan- about 120 days– 1% replaced each day– 3 million new RBCs per second!– If your body holds 6 liters and each blood donation

is 500 mL, how long before blood back to normal RBC count? Hint what % of your blood is removed?

RBC recycling

• Small amount ( 10%) hemolyze (rupture) in blood and proteins are filtered out by kidneys. Too many rupturing will give urine reddish/ brown color!!

• Usually phagocytic cells in the liver, spleen, and bone marrow engulf old RBCs and break them down into component parts.

• Heme molecule loses its iron and becomes biliverdin (green color)

• Biliverdin converted to Bilirubin ( orange yellow) and released into the blood, liver then absorbs and secretes into bile duct.

• Sometimes bilirubin will build up in tissue (visible in skin and whites of eyes), condition known as “Jaundice”. Sign of bigger problems!

• In fetus, mom’s liver is disposing of bilirubin. Upon birth is can take a couple days for baby’s liver to get up to speed! In the mean time baby gets funny color- “Jaundiced” yellow.

Severe Neonatal Jaundice Therapy

• Certain wavelength of light will break down bilirubin in skin!

• When bilirubin reaches Lg. intestine it is broken down further. Some is reabsorbed with water and released by kidneys, some goes out with feces. Thus urine’s yellow color and brown of feces.

RBC production

• Occurs in red bone marrow of larger bones ( proximal limb, pelvic, scapulae, etc.)

• When O2 levels low, kidneys release Erythropoeitin (EPO).

Blood types

• Red blood cells have about 50 different surface proteins

• These proteins are known as surface antigens• 2 types are problems when getting blood

transfusions: ABO and rh +/-• The body recognizes the ones you have and

produces antibodies against those you don’t• Page 376

White Blood Cells (WBCs or leukocytes)

• Larger than RBCs and have a nucleus and other organelles. They lack hemoglobin.

• Help defend against pathogens, remove wastes, toxins, and abnormal or damaged cells.

Types of WBCs

• Neutrophils: 50-70%, phagocytes that attack and digest bacteria

• Eosinophils: 2-4%, use exocytosis to attack toxic compounds

• Basophils: less than 1%, releases heparin (prevents clotting) and histamine (enhances inflammation)

• Monocytes: 2-8%, aggressive phagocytes

• Lymphocytes: 20-30%

WBC Movement and Circulation

WBCs are sensitive to chemical signs of damage to surrounding areas,

so when there is a problem WBCs leave the bloodstream and enter the

damaged area. • Amoeboid Movement: gliding motion that allows WBCs to move

along• walls of blood vessels• Diapedesis: leaving the bloodstream and entering surrounding

tissue• Positive Chemotaxis: attraction to chemical stimuli• Phagocytosis: engulf pathogens, cell debris, or other materials

Platelets

• In humans, these are cell fragments and not individual cells

• Initiate the clotting process and help close injured blood vessels

• A platelet circulates for 9-12 days before being removed

by phagocytes.

Hemostasis

Hemostasis: the process that stops bleeding by preventing the loss of blood through damaged vessel walls.

• Phase 1 (Vascular Phase): Cutting a blood vessel’s wall triggers a vascular spasm, which can slow or stop loss of blood through a small vessel

• Phase 2 (Platelet Phase): Platelets attach to exposed fibers to close the break in a small vessel

• Phase 3 (Coagulation Phase): As the network of caught fribrinogen grows, blood cells and platelets become trapped and form a blood clot.

Types of WBCs

• Neutrophils: 50-70%, phagocytes that attack and digest bacteria

• Eosinophils: 2-4%, use exocytosis to attack toxic compounds

• Basophils: less than 1%, releases heparin (prevents clotting) and histamine (enhances inflammation)

• Monocytes: 2-8%, aggressive phagocytes

• Lymphocytes: 20-30%