Question

ESSAYS Describe the types of Asthma, etiology and treatment. Discuss extrinsic (neural and humoral) and intrinsic control (autoregulation which should include myogenic mechanism and juxtaglomerular apparatus) of GFR regulation 3. Describe in detail formation of concentrated urine, including role of ADH, urea and countercurrent mechanism Define oxyhemoglobin dissociation curve. What is the significance of steep and plateau portion of the curve? Discuss all the factors that affect % saturation of hemoglobin including anemia, high altitude and heart failure.

Answer 1

Question: 1. Describe the types of asthma, etiology, and treatment?

Asthma types:

• Adult-onset asthma
• Allergic Asthma
• Asthma-COPD Overlap
• Exercise-Induced Bronchoconstriction(EIB)
• Non-allergic Asthma
• Occupational Asthma

Causes: There is no evidence of the underlying cause of asthma, but it is thought to be due to a combination of genetic and environmental factors. ... Common triggers for asthma include smoke from cigarettes, dust mites, air pollution, pollen, mold, respiratory infections, physical activity, cold air and allergic reactions to certain foods.

Treatment: Quick-relief inhalers (bronchodilators) expand swollen airways rapidly, which restrict breathing. Allergy medicines are required in some cases. The foundation of asthma diagnosis is long-term asthma management medications, usually taken regularly.

Question: 2. Discuss extrinsic (neural and humoral) and intrinsic control (autoregulation which should include myogenic mechanism and juxtaglomerular apparatus) of GFR regulation.

It is necessary to regulate renal blood flow to maintain a stable glomerular filtration rate (GFR) despite changes in systemic blood pressure (about 80-180 mmHg). The kidney regulates its own blood flow in response to changes in sodium concentration in a mechanism called tubuloglomerular feedback. The levels of sodium chloride in the urinary filtrate are detected at the end of the ascending limb by the macula densa cells. The macula densa releases ATP and decreases the transfer of prostaglandin E2 to neighboring juxtaglomerular cells when sodium levels are slightly increased. The juxtaglomerular cells in the afferent arteriole constrict, and both afferent and efferent arteriole juxtaglomerular cells reduce their renin secretion. Such acts work to lower GFR. To prevent excessive vasoconstriction, a further increase in sodium concentration results in the release of nitric oxide, a vasodilating drug. In the opposite case, juxtaglomerular cells are stimulated to release more renin, which activates the cycle of renin–angiotensin, releasing angiotensin I which is converted to angiotensin II by angiotensin conversion enzyme (ACE). Angiotensin II then allows the glomerulus' efferent arteriole to be preferentially constricted and raises the GFR.

Question 3: Describe in detail the formation of concentrated urine, including the role of ADH, urea and countercurrent mechanism.

Formation of Concentrated urine:

Henle loop and Anti-Diuretic Hormone are the factors responsible for the production of concentrated urine.

The loop of Henle creates a negative or low water potential in the medulla tissues so that more water gets absorbed from the fluid present in the collecting duct.

The Anti-Diuretic Hormone alters the permeability of the collecting duct walls. When the blood as low water potential, the posterior pituitary releases ADH because the neurosecretory cells in the hypothalamus get stimulated.

Role of ADH, urea and concurrent mechanism:

ADH : ADH is primarily responsible for dilute or condensed urine production. The single most important function of antidiuretic hormone is to retain body water by increasing urinary water loss. ... Antidiuretic hormone binds to receptors on cells in the collecting ducts of the kidney and promotes reabsorption of water back into the circulation.

Urea:

Urea plays an important role in the metabolism of animal compounds containing nitrogen and is the primary material containing nitrogen in mammalian urine. It is a solid, colorless, odorless, extremely water-soluble, and almost non-toxic.

Countercurrent mechanism:

The countercurrent multiplier's purpose is to generate the Medullary Interstitium hyperosmotic.The hyperosmotic Medullary interstitium is formed by the urea reabsorbed from the collection duct to the medullary interstitum.In the presence of ADH, urea should be reabsorbed.

Question 4: Define the oxyhemoglobin dissociation curve. What is the significance of the steep and plateau portion of the curve? Discuss all the factors that affect % saturation of hemoglobin including anemia, high altitude, and heart failure.

The dissociation curve of oxygen–hemoglobin, also known as the curve of oxyhemoglobin dissociation or the curve of oxygen dissociation (ODC), is a curve that plots the proportion of hemoglobin in its saturated (oxygen-laden) form against the prevailing oxygen pressure on the horizontal axis on the vertical axis. A curve is a vital tool for understanding how oxygen is transferred and released by our blood. Specifically, the oxyhemoglobin dissociation curve relates oxygen saturation (SO2) and partial pressure of oxygen in the blood (PO2), and is determined by what is called "hemoglobin affinity for oxygen"; that is, how readily hemoglobin acquires and releases oxygen molecules into the fluid that surrounds it.