Clin. Lab Theory: EXAM 3 - Bullet Points

This is a collection of all the difficult bullet points from my notes from of "Clinical Laboratory Science" by Mary Louise Turgeon 7th edition

What is hemosiderin?

Iron protein complex formed when the body breaks down hemoglobin after bleeding or hemorrhage

What cells store ferritin?

Macrophages

____ is iron in the Ferrous state where no hemoglobin is bound to oxygen, but it is still in a reduced state

Fe+2

____ is iron in the Ferric state where no hemoglobin is bound to oxygen, but the molecule is oxidized (Methemoglobin)

Fe+3

What are the 3 normal Hemoglobin variants?

HbA, HbA2, HbF

RBC values are ___ times the hemoglobin value?

3

Hemoglobin values are ___ times the hematocrit

3

What is Thalassemia a problem in? What type of anemia will it present as?

globin synthesis; presents as hypochromic-microcytic with target cells

What are Sideroblasts? What are Siderocytes? What does their presence indicate?

Sideroblasts are nucleated RBCs with granules of iron around their circumference. Siderocytes have no nucleus, but still have the iron: Indicates a problem with porphyrin or heme synthesis

What is the G1 checkpoint?

A checkpoint before the S phase of the cell cycle that checks for DNA damage and prevents progression into S phase

What does the S checkpoint do?

Monitors the accuracy of DNA replication during S phase

What does the G2 checkpoint do?

Monitors accuracy of DNA replication and checks of damage or unreplicated DNA and will block mitosis if found

What does the M/ Spindle Checkpoint do?

Make sure all chromosomes are aligned on the spindle between Metaphase and Anaphase

What do Cdks do in cell cycle control?

Phosphorylate target molecules to control the cell cycle and allow it to progress between phases

What do Cyclins do in the cell cycle?

Bind to Cdks to regulate the cell cycle

What do D cyclins regulate?

Growth factor hormones

What are p21 - p27 - p57 ?

Universal Cdk inhibitors that prevent uncontrolled cell growth

What are p15 - p16 - p18 - p19 ?

Specific proteins that induce cell cycle arrest at G1 and are especially important in preventing cancer

The default cell cycle phase of all Hematopoietic precursor cells is _____, but cytokines and cellular matrix proteins function to _____.

Apoptosis, suppress it

List of the order of the 4 areas Hematopoiesis takes place as you develop?

Yolk sac, liver, spleen, bone marrow

Where does primitive erythropoiesis occur?

in the yolk sac

When does definitive erythropoiesis begin?

When hematopoietic stem cells are first formed in the AGM

What are the primary hematopoietic organs?

Bone marrow and thymus

What are the 3 organs that do B and T cells development?

Spleen, thymus, lymph nodes

What are the (3) things contained in the vascular bone marrow?

arteries, stroll cells, hematopoietic cells

What are the (2) things happening/ present in the endosteal bone marrow?

bone remodeling and the presence of hematopoietic stem cells

What is the stroma in the bone marrow? What are (3) major components

A netowork of different cells that provide the favorable microenvironment for the proliferation of Hematopoietic Stem Cells; the 3 major components are macrophages, reticular cells, and adipocytes

What do reticular cells do in the Stroma?

Active leukocytes

What do adipocytes do in the Stroma of the bone marrow?

control the volume of bone marrow making space for stem cells

Describe the erythroblast island in the bone marrow. Why is it like this?

An area with a central macrophage surrounded by erythroblasts because the macrophage secrets cytokines

Where is the granulocyte nest within the bone marrow?

In the trabeculae

Where are the Lymphoid aggregates within the bone marrow?

Near arterioles

What 2 organs can make RBCs in adults if the bone marrow can’t keep up with the demand?

Liver and spleen

What are the (3) diagnostic criteria for hypersplenism

anemia, hyperplastic bone marrow, and splenomegaly

What phase of the cell cycle are Hematopoietic Stem Cells usually kept at?

Quinesence/ G0

Are progenitor cells morphologically distinct?

no

What does the osteoblastic niche do? (2)

Support and maintain hematopoietic stem cell quiescence and regulates their self renewal

What does the vascular niche do in the bone marrow? (2)

Signal for proliferation and differentiation

What do Hematopoietic growth factors/ cytokines do in the bone marrow?

govern percursor cell survival self renewal proliferation and differentiation, and suppress apoptosis

What does G-CSF regulate?

Neutrophils

What does Thrombopoietin regulate?

platelets

What does M-CSF regulate?

Macrophages and osteoclasts

What does SCF regulate?

Stem cells survival and division

What does Flt-3 ligand regulate?

progenitor cell expansion/ can send them into the cell cycle and B cells

What does G-CSF regulate?

granulocytes

What does IL-7 regulate?

Lymphocyte production

SCF and Flt-3 ligand are considered ________ growth factors.

Early acting

G-CSF, M-CSF, EPO, and TPO are considered _____ _____ growth factors.

Late acting

Cytokines bind to ______. ______ to activate the signaling pathway to recruit transcription factors

membrane receptors

What is the most common membrane receptor for hematopoiesis

JAK

What does JAK do in the JAK STAT signaling pathway?

Phosphorylate receptors which allows STAT to bind and then phosphorylates STAT

What does STAT do in the JAK STAT pathway?

Travels to the cell nucleus and activates transcription pathways to express certain genes for hematopoiesis

What does the Lymphoid Niche do in the bone marrow?

develop B cells

What does the Stem Cell Niche have in the bone marrow?

Stromal cells which secrete surface associates factors that restrain hematopoietic stem cell differentiation

What is Tissue Thromboplastin (Factor III)?

Any substance capable of converting prothrombin to thrombin

What does ionized calcium do in coagulation?

Activate thromboplastin and convert prothrombin to thrombin

What does Factor V do in coagulation?

Convert prothrombin to thrombin

What is the only unique extrinsic factor?

Factor VII

What are the 2 subunits of factor VIII?

VIII: C , VIII:vWF

Absence of _____ causes Hemophilia A

VIII:C

Absence of ____ cause Hemophilia B

Factor IX

What are key signs of Hemophilia A?

bleeding into joints and intramuscular hemorrhages and prolonged APTT testing

What does Factor VIII:vWF do in coagulation?

Allow for platelet adherence to subendothelial surfaces

What does Factor X do?

Generates thromboplastin

What triggers the extrinsic coagulation pathway?

The release of Factor III Thromboplastin (tissue factor) when cells are damaged since this is not normally found in the blood

What is the key step in the Common coagulation pathway?

activation of Factor X into Factor Xa

What happens in the common pathway once Factor X is activated to Factor Xa?

Factor V converts prothrombin to thrombin and thrombin converts fibrinogen to fibrin