Blood 101Peter Jean

What is blood?• Functions:• Transport of nutrients

and waste• Defense against internal

damage• Repair of damaged

tissues

Image: http://static.ddmcdn.com/gif/blood-cells.jpg

Hematopoiesis: The Differentiation of Progenitor Cells

http://apbrwww5.apsu.edu/thompsonj/Anatomy%20&%20Physiology/2020/2020%20Exam%20Reviews/Exam%201/hematopoiesis00.gif

Progenitor Cells

• Differentiated stem cells from bone marrow

• In hemapoiesis, progenitor cells are the starting material.

• Can be differentiated further into specific blood cells such as platelets, T-cells, and red blood cells (erythrocytes).

Platelets

• Not true cells, meaning they lack a nucleus.

• Membrane bound fragments derived cells in the bone marrow.

• Play a major role in blood clotting.

Image: http://www.daviddarling.info/images/blood_clotting.gif

Plasma

• The natural environment of blood cells, or the liquid phase of blood.• When blood is

centrifuged, 3 layers form.

• Top layer: plasma• Middle layer: the “buffy”

layer (mostly platelets)• Bottom layer: Red Blood

Cells (RBCs)Image: http://2.bp.blogspot.com/_FoiEZNQLqOI/TIi_PXga-eI/AAAAAAAABpU/NslutpCNkZ0/s1600/plasma-blood.gif

Leukocytes

• Also known as White Blood Cells (WBCs)• Different subgroups, including lymphocytes

and granulocytes.

• Protect against infection

• Mostly produced in bone marrow

• Have the ability to migrate out of the bloodstream into surrounding tissues.

Iron Transport and Storage

• Iron is essential for life, two oxidation states:• Fe2+ Fe3+

• A protein called ceruloplasmin donates a free electron, changing the oxidation state of iron.

• Transferrin protein protects the body against free iron, which has toxic effects, and TRANSFERS the protein to different parts of cell.

• Iron is important in RBCs because that is where oxygen (O2) binds to the Hemoglobin protein in the cell, and can be released in various tissues.

Image: http://sickle.bwh.harvard.edu/tf-endocytosis.gif

Hemoglobin

• Two structural figures: oxygenated and deoxygenated.

• Affected by the binding of O2.

• The chemical bonds between different “chains” are broken and others are formed, effectively rotating the shape of the protein.

Image: http://alexandria.healthlibrary.ca/documents/notes/bom/unit_2/Hemoglobin%20fig%201.jpg

What about Blood Type?

• Types: A, B, AB, O

• The difference? Antigens on the surface of RBCs recognize the differing types floating in the plasma. “O negative” type is the universal red blood cell donor, while “AB positive” is the universal plasma donor.

• There is also an Rh factor, which can be present (+) or absent (-).

Image: http://waynesword.palomar.edu/images/blood1.gif

The Fate of Red Blood Cells

• Last approximately 60 to 120 days.

• Cells that are ready to die are taken up (phagocytosed) by macrophages. The amino acids that make up the protein, are recycled.

• The hemoglobin is broken down into bilirubin. Bilirubin is toxic, so it must be transported to the liver via albumin where it is broken down and eventually excreted.

Image: http://ars.sciencedirect.com/content/image/1-s2.0-S1074552109002919-gr8.jpg

Blood Related Diseases: Hemophilia

• Inherited disease, caused by single gene mutation.

• All female children of men with hemophilia are carriers, very rare for a woman to have (1:25,000,000)

• Symptoms: bleeding into muscle, bruising easily, blood in urine, first sign usually bleeding gums.

• Testing: Bleeding time, Thrombin time (used to look at deficiencies in fibrinogen, also tests for liver disease).

• Hemophilia spread throughout royal houses in Europe as marriages were arranged to set up political alliances.

Blood Related Diseases: Acute Intermittent Porphyria

• Deficiency of the enzyme porphobilinogen deaminase (PBGD)

• More than 250 mutations have been identified.

• Symptoms include abdominal pain, irregular heart beat (tachycardia), acute psychosis, and respiratory paralysis.

• Treatment: family screening (DNA testing), aviodance of factors that are known to cause attacks, heme derivatives. Future treatment may include liver transplantation, gene and enzyme therapy.

• Vincent van Gogh may have been a case for AIP, as he worked tirelessly, fasted, and excessive consumption of absinthe.

Image: http://www.framedcanvasart.com/images/site/Van_Gogh.jpg

“Self-Portrait”