Anatomy and Physiology 2 Chapter 19 - Blood

what is the 2 components of blood and how are they separated by density?

• plasma: non-living fluid matrix that is ~90% water; contains proteins, nutrients, hormones, electrolytes, gases, and waste

• formed elements: living blood “cells” suspended in plasma; includes erythrocytes, platelets, and leukocytes

density

1. plasma = least dense

2. buffy coat (includes leukocytes and platelets)

3. erythrocytes = most dense

what are 3 characteristics of blood

1. variable color based on oxygenation (high O2 = scarlet, low O2 = dark red)

2. pH range of 7.35-7.45

3. average volume of blood depends on sex (males = 5-6 L, females = 4-5 L)

3 functions of blood

1. transportation (gas exchange): delivering O2 and nutrients to body cells, metabolic wastes to lungs and kidneys for elimination, and hormones to target organs

2. homeostasis: includes body temperature (absorbing and distributing heat), pH (alkaline reserve of bicarbonate ions for normal pH), and fluid volume (maintaining adequate fluid volume)

3. protection: prevent blood loss and infection

what are 3 plasma proteins

1. albumins: 60% of plasma proteins; act as a substance carrier (hormones), blood barrier, and major contributor to plasma osmotic pressure

2. globulins: 36% plasma proteins; binds different types of hormones

3. fibrinogen: 4% plasma proteins; form clots and repair blood vessels

what are 3 characteristics of erythrocytes

1. hemoglobin: used for gas transport and binds reversibly with O2

2. biconcave: increased surface area relative to volume making it efficient for gas exchange

3. anucleate: no mitochondria, nucleas, and other organelles; ATP production is anaerobic and don’t consume O2 they transport

hemoglobin

made up of globin (4 polypeptide chain) and heme (pigment bonded to chain); heme’s central Fe atom binds 1 O2; each Hb can transport up to 4 O2

hematocrit

a blood test that measures the percentage of your total blood volume that consists of red blood cells

oxyhemoglobin

when O2 attaches to hemoglobin in lungs

deoxyhemoglobin

when O2 unbinds from hemoglobin in tissues

carbaminohemoglobin

when CO2 attaches to hemoglobin in tissues

hematopoiesis vs. erythropoiesis

• hematopoiesis: the overarching biological process of blood cell formation in bone marrow; composed of reticular connective tissue and blood sinusoids

• erythropoiesis: a subset of hematopoiesis driven by EPO and focuses on the production of red blood cells in bone marrow; homeostasis depends on hormonal control and adequate supplies of iron, amino acids, and B vitamins

hematopoietic stem cells (hemocytoblasts)

give rise to all formed elements; hormones and growth factors push cell toward specific pathway of blood cell development, committed cells can’t change

how are blood cells in erythropoiesis destroyed and the fate of hemoglobin

macrophages eat old RBCs in the spleen

macrophages separate heme and globin; Fe is salvaged for reuse

bilirubin

a yellow pigment the degrades heme, secreted by liver in intestines; it’s degraded to pigment urobilinogen and leaves in stool as stercobilin

what is anemia and 3 types of anemia

anemia: low O2-carrying capacity; feel fatigue, pallor, shortness of breath, and chills

1. blood loss: rapid vs. chronic

2. low RBC production: low Fe, B-12 deficiency, reduced EPO secretion

3. high RBC destruction: Hb abnormalities in globin, infections, etc.

leukocytes

defense against disease; leave capillaries via diapedesis and move through tissue spaces by amoeboid motion and positive chemotaxis

what type of cell do granulocytes and agranulocytes originate from

myeloid stem cells

what are 3 granulocytes

1. neutrophils: highly mobilized and arrive at site of injury

2. eosinophils: attack objects coated with antibodies

3. basophils: contain histamine and heparin

what are 2 agranulocytes

1. monocytes: becomes a tissue macrophage

2. lymphocytes: continuously migrate through the bloodstream; 3 types which are T cells, B cells, and natural killer cells

list the granulocytes and agranulocytes by decreasing abundance

1. neutrophils

2. lymphocytes

3. monocytes

4. eosinophils

5. basphils

*Never Let Monkeys Eat Bananas

thrombocytes (platelets)

cytoplasmic fragments of megakaryocytes and help seal breaks in blood vessels; formation regulated by thrombopoietin

megakaryocytes

granules contain serotonin, Ca2+, enzymes, ADP, and PDGF

8 steps of hemostasis (blood clotting process)

1. vascular spasm: vasocontriction of damaged blood vessel; triggered by direct injury to smooth muscle, chemical release, and pain reflexes

2. platelet plug formation: damaged enothelium exposes collagen fibers (platelets stick to collagen fibers) and swelling occurs where it becomes spiked and sticky, releasing chemical messengers to attract more platelets/WBC

3. coagulation: series of reactions using clotting factors to reinforce platelet plug with fibrin threads

   1. prothrombin activator formed in both intrinsic and extrinsic pathways

   2. prothrombin converted to enzyme thrombin

   3. thrombin catalyzes fibrinogen to fibrin

4. clot retraction: stabilizes clot by pulling on fibrin strands, squeezing serum from clot, drawing the ruptured edges together

5. plasminogen in clot is converted to plasmid which breaks down fibrin

*includes the steps in coagulation

antigen

protein structure on red blood cell; anything perceived as foreign generates an immune response

antibodies

proteins produced by immune system to identify and neutralize harmful foreign substances

what is the universal recipient/plasma donor

AB+

what is the universal donor

O-

agglutination

antibodies stick onto antigens and stack multiple blood cells together; makes it difficult for bacteria to move around

erythroblastosis fetalis

only occurs in Rh- mom with Rh+ fetus; mom exposed to Rh+ blood during delivery of first baby where the mom synthesizes anti-Rh antibodies; when the mom is pregnant a second time with an Rh+ baby, the mom’s pre-existing antibodies cross the placenta and attack the fetus’s red blood cells