Lecture 10: Blood

what are the functions of blood?

transport, homeostasis, protection

what does blood transport?

• O2 and nutrients

• waste (ex. lung and kidneys)

• hormones

How does blood regulate homeostasis?

• migrating blood volume (core vs. extremities) for temperature

• pH

How does blood provide protection?

• WBCs (leukocytes) protect from infection

• blood loss → clotting

what is blood composed of?

plasma, buffy coat, and hematocrit

what does plasma contain?

water, proteins, nutrients, hormones, etc

what is the buffy coat made of?

WBCs and platelets

what is hematocrit?

RBCs

what is the pH of blood?

about 7.35-7.45

what are erythrocytes?

RBCs

what kind of shape do RBCs have, and why?

biconcave shape; more surface area = volume ratio for exchange

what is the cytoskeleton protein that allows RBC changing in shape for capillary passage?

spectrin

what do erythrocytes have that is required for gas transport?

hemoglobin (Hb)

Heme

red pigment that contains iron

Globin

4 chains of protein, each have heme

what binds to each iron in heme?

O2 (4O2 to 1 Hb)

lots of Hb in one erythrocyte = ?

lots of O2 moved

Hb + O2= ?

deoxyhemoglobin

Hb + CO2 = ?

carbaminohemoglobin

O2 movement is based on what?

• amount of erythrocytes

• amount of Hb in erythrocytes

what happens if blood oxygen is low?

hypoxemia

what do the kidneys do when they notice hypoxia?

secrete EPO

what is erythropoietin (EPO)?

hormone that stimulates erythrocyte production

what does erythropoietin target?

red bone marrow

low levels of erythropoietin always present to hold?

basal rate

making complete erythrocytes requires __________ and other materials?

iron

free iron ions are?

toxic- can lead to organ damage

what are the carrier proteins involved in storage of iron?

territin and hemosiderin

what carrier proteins are involved in transport of iron?

transferrrin

what is required in blood for DNA synthesis?

Vit B12 and folic acid good for rapidly dividing cells

why is copper needed in blood?

needed for hemoglobin production

what is anemia?

low erythrocyte count or low Hb

what are symptoms of anemia?

fatigue, pallor, dyspnea (trouble breathing), and chills

what are the 3 potential causes of anemia?

• blood loss

• too few erythrocytes made

• too many erythrocytes destroyed

what is hemorrhagic anemia?

rapid blood loss caused by severe wound

what is chronic hemorrhagic anemia?

lighter, but persistent blood loss (hemorrhoids or bleeding ulcer)

what is iron-deficiency anemia?

low iron intake/absorption

what are potential causes of iron-deficiency anemia?

• microcytes (small erythrocytes) instead of regular ones produced

• Unable to make hemoglobin due to lack of iron

what is renal anemia?

low EPO generally caused by renal disease (kidneys can’t make sufficient EPO)

what is aplastic anemia?

red bone marrow destroyed/inhibited; can be caused by drugs, chemicals, viruses, radiation, etc

what is polycythemia?

excess of erythrocytes or dehydration

what happens if someone has polycythemia?

• increased viscosity

• slow/sluggish blood flow

what is polycythemia vera?

bone marrow cancer (hematocrit can get to 80%)

what is secondary polycythemia?

Low O2 levels or increased EPO production

What is the function of leukocytes?

defense against various pathogens

what are leukocytes?

WBCs

what is diapedesis?

ability of WBCs to leave capillaries

what are the two categories of leukocytes?

• granulocytes

• agranulocytes

what are granulocytes?

cytoplasmic granules (most have phagocytic capability)

what are agranulocytes?

no granules

What are the types of granulocytes?

• neutrophils

• eosinophils

• basophils

what are the types of agranulocytes?

• lymphocytes

• monocytes

which type of granulocyte is the most common?

neutrophils (50=70% of WBC)

what are the characteristics of neutrophils?

• very phagocytic

• granules contain defensin or hydrolytic enzymes

• kill microbes via respiratory bust

what is defensin?

antimicrobial protein

how are microbes killed via respiratory burst?

synthesizes oxidizing substances (hydrogen peroxide)

how does defensin work?

pierces holes in membrane of ingested microbe

eosinophils play a role in what?

allergies and asthma

what are characteristics of eosinophils?

• granules contain digestive enzymes

  • target large parasitic worms - digest their surface

what are characteristics of basophils?

• granules contain histamine

• rarest of the WBCs

what is histamine?

inflammatory compound that causes vasodilation and attracts WBCs to inflamed areas

where are lymphocytes generally found?

lymph tissue (lymph nods, spleen) but some circulate blood

what are the types of lymphocytes?

• T lymphocytes (T cells)

• B lymphocytes (B cells)

what do T lymphocytes (T cells) do?

recognize virus-infected cells and tumor cells

What do B lymphocytes (B cells) do?

can make plasma cells that secrete antibodies

what do monocytes do?

leave circulation, enter tissues, and differentiate into macrophages

what are characteristics of monocytes?

• active phagocytic cells

• crucial against viruses, bacteria, and chronic infections

what do monocytes do in terms of immune response?

activate lymphocytes to mount immune response

what is leukopoises?

production of leukocytes

leukopoiesis is stimulated by?

chemical messengers from red bone marrow and mature WBCs

what are the messengers that stimulate leukopoiesis?

• interleukins

• colony-stimulating factors (CSFs)

what is leukopenia?

abnormally low WBC count

what is leukemia?

• cancer that produced abnormally high WBC count (generally one single type of abnormal cell)

• ex. lymphocytic leukemia: lymphocytes

what happens when someone has leukemia?

cancerous cells fill red bone marrow → anemias → internal hemorrhage or uncontrolled bleeding

what is mononucleosis?

highly contagious viral disease → epstein-Barr virus

what happens when someone has mononucleosis?

• increased numbers of agranulocytes

• affected lymphocytes are enlarged

what do platelets contain?

fragments of megakaryocytes

what is the function of platelets?

form temporary plug to seal breaks in blood vessels

what keeps platelets inactive and mobile?

nitric oxide and prostacyclin

what is thrombopoietin?

platelet production/formation

how is homestasis done in terms of hemorraging?

series of reactions to stop bleeding

what is the first stage of coagulation?

injury: blood leak/loss

what is the second stage of coagulation?

vascular spasm

• injury causes vasoconstriction

• reduces blood loss

what is the third stage of coagulation?

• platelet plug formation

what occurs during platelet plug formation?

• platelets stick to collagen fibers from vessel damage

• platelet activation leads to release of ADP, serotonin, and other factors

what does ADP do during blood coagulation?

gets more platelets stick which activate more platelets

what does serotonin do during blood coagulation?

maintains vasoconstriction

what is the fourth stage of coagulation?

coagulation

• fibrinogen converted to fibrin

• makes a “net” to catch more platelets and erythrocytes to form clot

• clots more effective at sealing larger vessels

what is a thrombus?

Persisting clot (unbroken blood vessel)

• can block circulation → necrosis

what is an embolus?

circulating thrombus in bloodstream

what is an embolism?

embolus obstructing a vessel (pulmonary or cerebral emboli)

what is an antigen?

anything is recognized as foreign → immune response

antigens are also known as ?

agglutinogens (promote agglutination/clumping)

what is one of the more volatile groups of agglutinogens that causes more intense transfusion reactions?

ABO and Rh

Type A blood, has what kind of antigen?

A

Type B blood, has what kind of antigen?

B

Type AB blood, has what kind of antigen?

both A and B

Type O blood, has what kind of antigen?

none

Anti-A binds to?

antigen A

Anti-B binds to?

antigen B