Issues Flashcards
Body weight percentage of blood
8%
What do RBCs have in their membranes?
Glycoproteins
Name 2 key erythorocyte enzymes.
- Glycolytic enzymes
- Carbonic anhydrase
Life cycle of erythrocyte
- Erythrocytes form in red bone marrow.
- Erythrocytes circulate in bloodstream for 120 days.
- Aged erythrocytes are phagocytized in the liver and spleen.
- Heme components of blood are recycled.
- Membrane proteins and globin proteins are broken down into amino acids, some of which are used to make new erythrocytes.
What happens to heme components recycled?
- Heme is converted into biliverdin and then to bilirubin which is secreted in bile from the liver.
- Iron is transported in the blood by the protein transferrin and stored by the protein ferritin in the liver.
How does erythropoetin from kidney stimulate erythropoiesis?
- Kidneys detect reducted O2 carrying capacity of blood.
- When less O2 is delivered to the kidneys, they secrete erythropoetin into blood.
- Erythropoietin stimulates erythropoiesis by bone marrow.
- Additional circulating erythrocytes increase O2-carrying capacity of blood.
- Increased O2-carrying capacity relieves initial stimulates that triggered erythropoietin secretion.
NB! Platelets (thrombocytes) details
- smallest elements in blood
- lack nucleus
- fragments of megakaryocytes
- make most of mass of blood clots
- release serotonin (vasoconstrict, reduce blood flow to clot)
- secrete growth factors (maintain integrity of blood vessel wall)
- survive 5-9 days (removed by tissue macrophages)
Where is thrombopoeitin produced?
Liver
Where is erythropoeitin produced?
Kidney
3 steps in Hemostasis
- Vascular spasm
- Formation of a platelet plug
- Blood coagulation (clotting)
Beta (β) globulins function
Inactive precursor proteins eg proteases
Hemostasis
Blood clotting
What happens to heme components recycled?
- Heme is converted into biliverdin and then to bilirubin which is secreted in bile from the liver.
- Iron is transported in the blood by the protein transferrin and stored by the protein ferritin in the liver.
What is the function of innate immune cells
- Complement protein & peptides in blood/tissue
- Beat trivial infections
What is the function of T-lymphocytes?
- Priming of innate responses (T-helper 1, TH1)
- Priming of antibody responses (T-helper 2, TH2)
- Direct cell lysis (cytotoxic T’s)
What are monocytes attracted by?
- Histamine
- Cytokines
What are the types of fixed macrophages?
- Dust/Alveolar type (lungs)
- Histiocytes (connective tissue)
- Kupffer cells (liver)
- Microglial cells (nervous)
- Osteoclasts (bone)
- Sinusoidal lining cells (spleen)
What do natural killer cells release?
Perforin
What do natural killer cells function in?
In rejection of tumors and cells infected by viruses
Leptin, release, function
Released from stored fat, suppressed appetite, dominant long-term regulator of energy balance and body weight.
What do the 2 subunits of the arcuate nucleus release?
One - neuropeptide Y
Other - melanocortins
Which adipokines is suppressed in obesity?
Adiponectin
What is neuropeptide Y?
An appetite stimulator
What is melanocortin?
An appetite supressor
Function of visfatin
Stimulates glucose uptake; binds with insulin receptor at a site distinct from the insulin-binding site
