Physiology

Hormones are carried by the blood throughout the entire body, yet they affect only certain cells.  The specific cells that respond to a given hormone have receptor sites for that hormone.     This is sort of a lock and key mechanism.  If the key fits the lock, then the door will open.  If a hormone fits the receptor site, then there will be an effect.  If a hormone and a receptor site do not match, then there is no reaction. &nbsp…

The Kidneys The kidneys are the primary functional organ of the renal system. They are essential in homeostatic functions such as the regulation of electrolytes, maintenance of acid–base balance, and the regulation of blood pressure (by maintaining salt and water balance). They serve the body as a natural filter of the blood and remove wastes that are excreted through the urine. They are also responsible for the reabsorption of water, glucose, and …

Partial Pressures of O2 and CO2 in the body (normal, resting conditions): Alveoli PO2 = 100 mm Hg PCO2 = 40 mm Hg Alveolar capillaries Entering the alveolar capillaries PO2 = 40 mm Hg (relatively low because this blood has just returned from the systemic circulation & has lost much of its oxygen) PCO2 = 45 mm Hg (relatively high because the blood returning from the systemic circulation ha…

Asthma = Reversible Bronchioconstruction 4%-5% of population     Extrinsic / Atopic = Allergic, inherited (familia), chromosome 11     IgE, Chemical Mediators of inflammation      a.    Intrinsic = Negative for Allergy, Normal IgE, Negative Allergic Tests     Nucleotide Imbalance cAMP/cGMP: cAMP = Inhibits mediator release, cGMP = Facilitates mediator release b.    Into…

Platelets Platelets are cell fragments produced from megakaryocytes. Blood normally contains 150,000 to 350,000 per microliter (µl). If this value should drop much below 50,000/µl, there is a danger of uncontrolled bleeding. This is because of the essential role that platelets have in blood clotting. When blood vessels are damaged, fibrils of collagen are exposed. von Willebrand factor links the collagen to platelets forming a plug of plat…