226 anatomy: blood objectives

What percentage of blood is formed elements (RBC, WBC, and platelets) and what percent is plasma (fluid)?

formed elements: 45%

plasma: 55%

What is the percentage of platelets, RBC, and WBC in formed elements?

platelets: 4.8%

RBC: 95.1%

WBC: 0.1%

What is the most abundant thing in plasma?

water (92%) and proteins (7%)

Describe the anatomy of a Erythrocyte (red blood cell)

• biconcave shape

• no nucleus or organelles

• delivers hemoglobin

• life span=120 days

• typical count= 4.2-6.1 million/µL

What is erythropoiesis?

the process in which new red blood cells are produced

*everyday you replace about 8% of RBC

Describe the life cycle of erythrocytes

negative feedback mechanism

• stem cells turn into progenitor cells to develop into immature RBC

• produces lots of hemoglobin

• mature erythrocyte and enters bloodstream

• macrophages in liver and spleen break down old blood cells (hemoglobin broken down)

• heme is broken down into iron

*Controlled by erythropoietin

What happens to iron and heme after an erythrocyte is destroyed?

heme is broken down into iron

heme: broken down into biliverdin (green) and converted to bilirubin (orange)

iron: recycled/stored to produce hemoglobin and myoglobin

describe the lifecycle of a bruise

purple: hemoglobin low in o2

green/orange/yellow: hemoglobin breaking down

macrophages remove those pigments and breakdown the pieces and are eliminated in bile

What are some symptoms of sickle cell anemia?

• low O2

• poor blood flow

• blood cells get caught in the vessels and can’t circulate very well

What does type A blood have in it?

antigen A and antibody B

What does type B blood have in it?

antigen B and antibody A

What does type AB blood contain?

antigen A and B with no antibodies

what does type O blood contain?

no antigens and anti-A and anti-B

What is a fun fact about antibodies?

by 6 months old, a baby will have self manufactured the antibodies

What is the Rh factor (D antigen)?

if the blood is positive for Rh/D antigen, then you have positive blood and negative=negative blood

• if you lack these antigens, the antibodies do not form naturally

What is agglutination?

when antibodies and antigens in the blood react and clump together

What is coagulation?

when the blood clots

How do you choose what blood a person can receive for transfusions?

you can’t give someone antigens they do not already have or the antibodies will react

• all depends on the antigens

What is Erythroblastosis Fetalis?

occurs when the mother is Rh- and the anti-D antibodies cross into the placenta, only becomes a problem after the first pregnancy

• can be treated with drugs

What is the difference between a phenotype and a genotype?

phenotype= physical trait

genotype=genes you inherit

what is important to follow when figuring out the genetics of blood types?

you have to assume someone is heterozygous unless told otherwise

• O- and AB- blood is always homozygous

What are leukocytes?

white blood cells

What is a granulocyte?

• contains cytoplasmic granules

• polymorphonuclear (nucleus takes on many shapes)

• life span= about 12 hours (everyday you replace all of them twice)

What is a agranulocyte?

• lacks cytoplasmic granules

• nucleus is oval or lobed

• life span= weeks to years (contains long term immunity cells)

What specific cells are granulocytes?

• neutrophils, eosinophils, and basophils

what specific cells are agranulocytes?

monocytes and lymphocytes

What is the job of neutrophils?

• general phagocytosis

• first to show up when you cut yourself

  • first line of defense against infection

• after fighting infection, they die

  • dead neutrophils+bacteria+debris=pus

• lives hours to days

What is the job of eosinophils?

• deal with parasitic infections

  • release toxic substances to kill it

• allergic rxns

  • increase inflammation

• lives days to about a week

What is the job of basophils?

• produce histamine

  • increase blood flow/vessels dilate (swelling, redness, and itching)

• produce heparin

  • anticoagulant: warms injury sight to kill infection

• least common and only live 12 hours

what is the job of monocytes?

• cleanup crew

• help to clean up infection

  • lives longer than neutrophils

• can leave the bloodstream and become macrophages in connective tissue

• largest type of white blood cells

What is the job of lymphocytes?

• involved in immunity

  • some become memory cells

• some produce antibodies

What is the origin of T lymphocytes?

travel red bone marrow in thymus where they mature

What is the origin of B lymphocytes?

originate and mature in bone marrow

What is the major histocompatibility complex?

helps T cells recognize when an antigen s “foreign” and not “self”

Describe immune response (cell-mediated immunity)

Directly attacking infected or abnormal cells

1. a cell engulfs a pathogen and displays pieces of it on its surface

2. helper T cells see this and start releasing interleukins

3. interleukins stimulate cytotoxic T cells to multiply and activate

4. cytotoxic T cells find the infected cells and cause them to die

5. some T cells become memory cells to allow for a faster response if that same pathogen appears again

What is the humoral immune response?

B cell activation (usually requires the help of T cells/cytokines)

*uses antibodies in body fluids

1. B cells bind with foreign antigen

2. B cells divide and make many identical cells

3. cells become either plasma cells or memory B cells

• memory cell: reacts quickly when interacting with the same foreign antigen again

Describe the anatomy of platelets

• fragments of cells

• function=helps to control bleeding

  • forms platelet plug

• normal count= 150,000-350,000 µL

• life span= 7-10 days

Why are platelets not technically called thrombocytes?

they are not whole cells which is what the word cytes implies

What are the major components of blood plasma?

water (92%), proteins (7%), and other solutes

What specific proteins make up blood plasma?

albumins, globulins, and fibrinogen

What is the job of albumins?

colloid osmotic pressure

What is the job of globulins?

transport lipids; immunity

What is the job of fibrinogen?

blood clotting

What is hemostasis?

maintain blood volume by limiting loss

• controls bleeding

What are the steps to hemostasis?

1. vascular spasm: blood vessel constricts (reduce flow)

2. platelet plug formation

3. coagulation: blood clot (fibrinogen)

describe the steps of platelet plug formation:

1. Break in vessel wall

2. blood escapes through the break

3. platelets adhere to each other at the end of the blood vessel, and to the exposed collagen

4. platelet plug help control blood loss

*platelets respond to exposed connective tissue

what mechanisms are used to prevent abnormal clotting?

1. anticoagulant pathway: antithrombin and heparin

2. fibrinolytic pathway: breaks down fibrin and uses plasminogen → plasmin

What is the basic mechanism of blood coagulation?

1. Prothrombin is activated

2. converts prothrombin to thrombin

3. thrombin converts fibrinogen to fibrin

4. it stabilizes into a fibrin clot

Why is blood coagulation considered a positive feedback mechanism?

each step amplifies the next

• chain reaction: small clots at first then more and more

What is the extrinsic clotting mechanism?

triggered by something other than in the blood

• damaged tissues release factor and then leads to prothrombin activator

What is the intrinsic clotting mechanism?

triggered by a substance in the blood

• blood contacts foreign substance which activates the Hageman factor and leads to prothrombin activator