Amphipathic molecules; Components of blood

What would happen if there was a vitamin B12 malabsorption?

Pernicious anemia. B/c Vitamin B12 and Folic acids required for maturation RBC. (and in order for B12 to be absorbed, intrinsic factor--folic acids-- are needed) Folic acid is present in green vegetables, some fruits, and liver.

What is required for maturation of RBC?

Vitamin B12 ( extrinsic factor) and Folic acids (intrinsic factor) B12 needs folic acid from GI tract for absorption

Lipophilic

"Lipid loving" - Tend to combine with or soluble in lipids

Hydrophobic

"Water fearing" - Water insoluble - Nonpolar - Symmetrical

Hydrophilic

"Water loving" - Water soluble - Polar - Non-symmetrical

In RBCs, 90-95% of glucose is used for what? What is the other 5-10% used for?

- 90-95% used for generating ATP through glycolysis - 5-10% used for the hexose monophosphate pathway (HMP) to produce NAPDH NADPH can reduce oxidative stress

What are the major components of blood?

- Cellular fraction (RBC, WBC, and platelets) - Noncelluar fraction (Plasma--water, protein, other; & serum)

Where are RBC produced?

- Embryonic stage: yolk sac, liver, lymphoid tissues - After birth: BONE MARROW *

What does the mitochondria do in Platelets (thrombocytes)?

- Form ATP (for energy) - Form ADP (vasoconstriction) - Synthesize PROSTAGLANDINS --> cause vascular rxns

Characteristics of erythrocytes (RBC)

- Non-nucleated - Lack most organelles (including mitochondria) - Metabolically highly active - Biconcave shape

What energy source do RBC utilize?

- Uses glucose as it's only (absolute) energy source. - Glycolysis--not efficient, but very rapid. Glucose is preferred energy source for brain neurons

What cells make up the cellular fraction of blood?

1) Erythrocytes (RBC). - most of cell mass 2) Leukocytes (WBC) - The body's defense 3) Thrombocytes (blood platelets) - fragments of big cells--megakaryocytes

What 2 components make up the noncellular fraction of blood

1) Plasma 2) Serum

What are the major components of plasma

1) Water (93%) 2) Protein (7%) - albumin - globulins - Fibrinogen 3) Small M.W. materials (molecular waste?) Lipids???? They are carried by lipid proteins that are amphiphatic molecule. Part of globulins.

Characteristics of Platelet cell membranes

1) coat of GLYCOPROTEINS - repulse adherence to normal endothelium and yet cause adherence to injured area of vessel wall (endothelial cells and collagen) 2) Rich in PHOSPHOLIPIDS -coagulation

What is RBC's shape and why

Biconcave - Wider surface area = easier to diffuse

function of erthrocytes (RBC)

Combine with oxygen, carry oxygen to peripheral cells, dump O2, load Co2.

In vivo, Plasma is ______

EXTRACELLULAR FLUID in the blood.

What is most essential regulator in production of RBC?

HYPOXIA: lower partial pressure of oxygen. Body does not have enough oxygen for metabolic needs. Hypoxia will cause increase in erythropoietin (EPO) from KIDNEYs --> Will stimulate bone marrow to produce RBC

Platelets contain mitochondria, but do not contain _______

No nuclei. Cannot reproduce.

Difference in plasma and serum

Serum = plasma - clotting factors

What is serum?

The overlying extracellular fluid in blood AFTER CLOT formation. Blood removed from vascular system will clot. Clot composed of fibrin and cellular elements enmeshed in the fibrin strands. The surrounding fluid is serum

what do Platelets contain to help with contraction when activated?

They contain ACTIN, MYOSIN, and THROMBOSTHENIN (contractile proteins. Cause contraction when ACTIVATED.

How does RBC reduce oxidative stress?

Uses little of glucose for HMP pathway to produce NADPH, which reduces oxidative stress In RBC, oxidative stress is abundant b/c it is involved with transfer of O2.

Amphipathic

amphi = both - Has both hydrophilic (polar) head and hydrophobic (nonpolar) tail

In vitro, Plasma is ______

extracellular fluid portion of the blood when an appropriate ANTICOAGULANT is added and blood is allowed to be centrifuged. The overlying fluid is plasma