MILKING EJECTION REFLEX IN ANIMAL
Removal of milk from the mammary gland is dependent on a functional milk ejection reflex. This is a neurohormonal- dependent process. The ejection of milk results from a nervous stimulus that an animal associates with milking or suckling activity, such as manual massage of the udder teats, suckling, or sight and smell of the calf.
the milking machine itself can also stimulate the reflex. The neural stimulus reaches the central nervous system and causes the posterior lobe to release oxytocin. Oxytocin reaches the mammary gland and myoepithelial cells, and contracti on of these cells forces milk from the alveoli into the duct system. Milk then flows freely into the larger ducts and cisterns. Adrenalin inhibits milk ejection primarily by reducing blood flow to the gland so that sufficient concentrations of oxytocin can not be reach the receptors on the myoepithelial cells. it is called MILKING EJECTION REFLEX IN ANIMAL
ACID BASE BALANCE..=
Acid–base balance is the homeostatic regulation of the pH of the body’s extracellular fluid (ECF). The proper balance between the acids and bases (i.e. the pH) in the ECF is crucial for the normal physiology of the body, and cellular metabolism. The pH of the intracellular fluid and the extracellular fluid need to be maintained at a constant level.
Acid-base balance is important for maintaining the narrow pH range that is require for various enzyme systems to function optimally in the body. Normal blood pH ranges from 7.3-7.4.3 Decreased pH is termed acidemia and is cause by an increase in the concentration of hydrogen ions ([H+]). Increase blood pH is termed alkalemia and is cause by a decrease in the [H+].
- The buffer systems that maintain this pH balance are bicarbonate, phosphates, and proteins. Bicarbonate is the most important extracellular buffer, while phosphates and proteins contribute mostly to intracellular acid-base balance.
- The bicarbonate system is the only buffer measure for the calculation of acid-base status in patients and is represent by the equilibrium equation CO2 + H2O <—> H2CO3 <—> H+ + HCO3-.
- In addition to buffers, the lungs and kidneys play a major role in acid-base homeostasis. The lungs function in ventilation and they are responsible for regulating the amount of CO2 present in plasma. The kidneys are responsible for controlling the amount of HCO3- in the blood by resorbing or excreting it in the proximal tubule.
- Simple acid-base disorders are common clinically, and 4 possibilities can arise: Metabolic acidosis. Metabolic alkalosis Respiratory acidosis Respiratory alkalosis MILKING EJECTION REFLEX IN ANIMAL