ch 17: Blood

composition of blood

composed of plasma and cells, which can be separated

what is plasma

liquid protein—fluid, water, electrolytes, proteins, gases

what is blood

the life-sustaining transport vehicle of the cardiovascular system

functions are transport, regulation and production

a connective tissue

what are the cells suspended in plasma

erythrocytes—transportation of gases

leukocytes-immune system

platelets—clotting machinery

what are the layers of blood

hematocrit—RBC, ~45%

buffy coat—WBC, ~1%

plasma— ~55%

what is plasma

liquid without cells but rich in protein

mostly produced by liver

albumin makes majority of plasma proteins, whih carry objects not water soluble

aspects of blood

sticky, opaque with metallic taste (high iron content)

color varies with O2 content

pH of 7.4 for artery blood

makes up ~6% of body weight

avg 5-6 L in men and 4-5 L in women

aspects of blood cells

most cells only survive in the bloodstream for a few days

most cells originate in the bone marrow and do not divide

Leukocytes

complete cells, have nucleus and organelles

function in immunity against disease

not confined to cardiovascular system

how do WBCs travel outside the cardiovascular system

1. margination—the WBC grabs onto wall of artery

2. Diapedesis—go through hole in the “wall”

3. chemotaxis—the WBC goes to the problem

categories of WBCs

granulocytes and agranulocytes

the granulocytes

neutrophils, eosinophils, and basophils

the agranulocytes

lymphocytes and monocytes

what is the WBC volume of each

Neutrophils—50-70%

Lymphocytes—25-45%

Monocytes—3-8%

Eosinophils—2-4%

Basophils—0.5-1%

Neutrophils

usually have 3 nuclei

eats phagosomes

dominant in bacteial infections

hydrolytic enzymes and antimicrobial proteins

eosinophils

antiparasitic, eats worms

large, red-staining granules

basophils

heightened inflammatory response, dont attack

blood clotting, attract other WBCs to the problem

rarest of the granulocytes

contains histamine (vasodilator) and herparin (prevents blood clotting)

lymphocytes

adaptive immunity, transforms into T or B cells

T cells act against viral infection, turmos, and unmatched transplants

B cells give rise to plasma cells, which produce antibodies

monocytes

largest WBC

differentiates into macrophages or DCs

highly active phagocytic

activate lymphocyte population (T cells)

Erythrocytes

no nuclei or organelles, break down rapidly

majority of cells in blood

transport O2 and CO2

biconcave disc shape

filled with hemoglobin for gas transport

ATTP production is anaerobic, so they do not use the O2 they transport

hemoglobin

binds reversibly to oxygen (attach and detach)

heme contains iron and pigment

globin is the protein structure

oxygen binds to Fe

how does oxygen bind to iron

breathing in, O2 loading in lungs, oxygen binds to iron, producing ruby red oxyhemoglobin

breathing out, O2 unloading in tissues, oxygen detaches and turns into dark red deoxyhemoglobin

hematopoiesis

the formation of all the cells of the blood

occurs in blood

hematopoietic stem cells have potential to become RBC or WBC

hormonea dn growth factors push cell toward a specific pathway

erythropoiesis

formation of red blood cells

three steps:

ribosome synthesis
hemo accumulation
eject organelles

reticulocyte

circulated out of the bones at the end of erythropoiesis

reticulocyte count indicates rate of erythropoiesis in the body

how is RBC production controlled

hormonal controls and dietary requirements

hormonal controls in RBC production

erythropoieton (EPO) stimulates the formation of erythrocytes

always a small amount of EPO in the blood to maintain basal rate

released by kidneys in reponse to hypoxia

dietary requirements in RBC production

iron available from diet

vitamin B12 and folic acid for DNA synthesis

Breakdown of RBCs

heme (red) goes to liver, becomes bilirubin (yellow/green) which goes to kidneys OR is secreted in bile via the liver to go to the intestines

intestines convert it into urobilinogen, some goes into kidneys and some stay in intestines

kidneys convert urobilinogen to urobilin (yellow) into urine

intestines convert urobilinogen to stercobilin (brown) into feces

anemia

low O2 carrying capacity due to low RBC count

pallor, fatigue, dyspnea, chills

due to not enought RBCs being made or too many being destroyed

polycythemia

excessive RBCs

increases blood viscosity, causing sluggish blood flow

iron-deficiency anemia

not making enough RBCs

RBCs called microcytes (small and pale) and cannot synthesize hemoglobin due to lack of iron

pernicious anemia

autoimmune disease that destroys stomach mucosa, lack of vitamin B12 absorption

renal anemia

lack of EPO in the kidney, accompanies renal disease

aplastic anemia

destruction/inhibition of red bone marrow, all cell lines affected

hemolytic anemia

too much RBC breakdown

ex malaria and sickle-cell anemia

platelets

thrombocytes

cell fragmebts

chemicals involved in blood clotting

form temporary platelet plug

formation regulated by thrombopoieton, which is produced by liver and kidney

hemostasis

fast series of reactions for stoppage of bleeding, requires clotting factors

1. injury

2. vascular spasm

3. platelet plug formation

4. coagulation

vascular spams

to prevent further blood loss, vasoconstriction

triggered by direct injury to vascular smooth muscle

chemicals released by endothelial cells and platelets

platelet plug formation

band aid over bleed, platelets stick to collagen fibers of damaged vessels

platelets swell and become spiked and sticky, attracting more cells to injury

coagulation

blood clotting

blood becomes a gel-like solid

13 clotting factors

3 general phases of coagulation

1. ends with formation of prothrombin activator

2. prothrombrin activated and transformed to active enzyme thrombin

3. creation of fibrin mesh, platelets and cells glued together to catch cells

clot retraction

30 mints to 1 hr after clot forms, clot pulls together when damage has been repaired, pulls wound together

fibrinolysis

clots are removed after repair is complete

Blood types

RBC membranes bear different antigens (or agglutinogens) called A or B

blood has to be processed and only hematocrit should be transferred

body produces antibodies against the antigens (A and B) NOT present

Rh factor

+/- symbol indicates presence of Rh factor

Rh factor can produce after being given mismatched blood

CMP

comprehensive medical panel

blood chemistry profile to check levels, abnormal results indicate liver or kidney disorders

CBC

complete blood count

checks cell levels, hematocrit, hemoglobin