Question

1. What are some physiological mechanism to control blood pressure
2. Name different blood buffers and their functions
3. Acid-base balance mechanism
   1. 1st and 2nd line of mechanism
4. What are the effects of hydrogen ions on contractile proteins
5. What are sources of hydrogen ions during exercise
6. What is Hb-O2 affinity

Answer 1

1 a) Renin-Angiotensin-Aldosterone System (RAAS) : In which renin is releases in response to low blood pressure.

b) Anti Diuretic hormone released from hypothalamus in response to low blood pressure.

c) Atrial natriuretic peptide (ANP) is synthesised and stored in cardiac myocytes. It is released when the atria are stretched, indicating of high blood pressure.

d) Baroreceptors. Increased blood pressure stretches the wall of the blood vessel, triggering the baroreceptors resulting in parasympathetic stimulation, decrease in blood pressure detected by baroreceptors, which then trigger a sympathetic response.

2 .The buffer systems functioning in blood plasma include plasma proteins, phosphate, and bicarbonate and carbonic acid buffers. Most important is the Bicarbonate - carbonic acid buffer system, the bicarbonate buffer is the primary buffering system of the interstitial fluid surrounding the cells in tissues throughout the body, in this system when sodium bicarbonate (NaHCO3), comes into contact with a strong acid, such as HCl, carbonic acid, which is a weak acid, and NaCl are formed. When carbonic acid comes into contact with a strong base, such as NaOH, bicarbonate and water are formed, thus  a weak acid or weak base captures the free ions, and a significant change in pH is prevented.

In addition to this our respiratory system also plays as buffer system by hyperventillating when excess CO2 is present and hypoventillating when CO2 is low.

3. Acid-base balance refers to the mechanisms the body uses to keep its fluids close to neutral pH , so that the body can function normally.The body's acid– base balance is tightly regulated to keep the arterial blood pH between 7.38 and 7.42.

4.) The kidneys help control acid-base balance by excreting hydrogen ions and generating bicarbonate that helps maintain blood plasma pH within a normal range. The respiratory system contributes to the balance of acids and bases in the body by regulating the blood levels of carbonic acid

5) Hydrogen ion can cause muscle fatigue and impaired muscle force, the accumulation of H+ lowers the pH, thus potentially interfering with sarcoplasmic reticulum calcium release,, troponin C sensitivity to Ca2+ and cross-bridge cycling and resulting in impaired muscle force

6. Source of hydrogen ion, Production of lactic acid during exercise. The breakdown of ATP for energy during muscle concentration results in the release of H+ ions.

7. Hemoglobin affinity to oxygen (Hb-O2 affinity) is a measure of how readily hemoglobin acquires and releases oxygen molecules into the fluid that surrounds it