Physiology Flashcards
What is Fibrin?
Insoluble protein that is used to repair tissue damage by forming a clot over the wound to hinder blood flow.
Fibrinogen is converted to fibrin
What are the four major functions of blood?
Transport
Homeostasis
Self Defense
Immunity (Defense)
Why do we use RBC to transport O2?
O2 is poorly soluble in water. Needs a carrier.
What is the function of Glomus cells? Where are they located?
They are in the Carotid Body
They monitor partial pressures of oxygen in the blood, and signal afferent fibers to the brain when there is low PO2 or high H+ concentrations.
As the partial pressure in arteries lowers, the nerve fires less
Explain the cellular change during hypoxia and normoxia
Hif-a binds to VHL when there is oxygen. This allows ubiquitin to bind to the protein complex for proteasomal degradation.
In hypoxia Hif-a is undbound and binds to Hif-B and this complex acts as a transcription factor. This stimulates erythropoesis, affects metabolism, and induces angiogenesis.
What is Erythropoietin (EPO) and where is it used?
EPO is increased in the kidneys when there is hemolysis or lowering of PO2 (due to altitude etc..)
HIF-1a induces EPO mRNA to increase viable EPO
The increase of EPO increases the numbers of RBC that are created.
What are the levels of EPO and the Hematocrit of someone with Aplastic Anemia?
Lowered Hematocrit and high EPO
EPO is created in excess to increase hematocrit but someone with aplastic anemia does not respond to the EPO and so their hematocrit remains low.
What are the hematocrit and EPO of someone with renal failure?
Polycythemia Vera?
Renal failure: Low EPO and low hematocrit
Polycythemia Vera: Low EPO and High hematocrit.
What transports CO2 in the blood?
90% by RBC
10% by plasma
The majority is bicarbonate. Most of it is in the form NaHCO3
20/1 NaHCO3 to H2CO3
What system keeps water homeostasis?
What happens when there is a problem?
What are two examples?
Capillaries and Lymph Vessels
Edema
Lymphatic Filariasis: Nematodes that migrate from mosquito bites to the lymph system that physically block the lymph causing huge edema.
Kwashiorkor: Edema for extreme wasting of underlying tissues. Causes streaky red or gray hair.
What changes the body temp in the blood?
Vasoconstriction keeps in the heat
Vasodilation (active) releases heat.
What acts as a buffer of H+ in the blood?
HCO3-
An increase in HCO3- or a decrease of CO2 will cause the pH to rise in the blood.
