Renal Physiology Lectures 33-45

A substance that is filtered at the glomerulus and is not reabsorbed or secreted by the tubules. Inulin is used as a gold standard for measuring glomerular filtration rate (GFR).

The rate at which the kidneys remove a substance from the blood stream. It is commonly measured using inulin.

The process by which substances are moved from the tubules back into the blood stream. It is important for conserving essential molecules and regulating blood volume.

The process by which substances are moved from the blood stream into the tubules of the kidney. It is important for eliminating waste products and regulating blood composition.

Sodium, magnesium, calcium, phosphate, bicarbonate, amino acids, glucose, and water are all reabsorbed to varying degrees in the proximal tubule.

Proteins and peptide hormones are reabsorbed by endocytosis in the proximal tubule. This is a different mechanism than transporter-mediated reabsorption.

The maximum rate at which a substance can be reabsorbed by the kidneys. When the concentration of a substance in the blood exceeds the transport maximum, it will be excreted in the urine.

The proximal tubule plays a crucial role in regulating blood volume by reabsorbing significant amounts of sodium and water. This process is fine-tuned according to various physiological states, such as reduced extracellular volume.

A measure of the hydrogen ion concentration in a solution. A lower pH indicates a higher concentration of hydrogen ions, making the solution more acidic.

The pH at which a weak acid is 50% dissociated. It represents the acid's strength.

The concentration of the conjugate base (the anion form) of a weak acid in a solution. It indicates the amount of the acid that has lost a proton.

The concentration of the weak acid (proton donor) in a solution. It indicates the amount of the acid that has not yet lost a proton.

A condition in which the blood pH is too low, often due to an excess of CO₂ in the blood.

A condition in which the blood pH is too high, often due to a decrease in CO₂ in the blood.

A condition in which the blood pH is too high, often due to an excess of bicarbonate ions (HCO₃⁻) in the blood.

A condition in which the blood pH is too low, often due to a decrease in bicarbonate ions (HCO₃⁻) in the blood.

The arcuate nucleus integrates signals from peripheral hormones like leptin, insulin, and ghrelin to maintain energy homeostasis, ensuring that food intake is balanced with the body's energy needs.

Agouti-related protein (AgRP) is a neuropeptide that stimulates appetite and reduces energy expenditure. It is a powerful and long-lasting appetite stimulant, playing a significant role in regulating energy balance.

Irritable bowel syndrome with diarrhea (IBS-D) is a gastrointestinal disorder characterized by frequent loose stools and abdominal pain. It is diagnosed by the presence of elevated antibodies against CdtB (cytotoxic diarrheal toxin) and Vinculin.

Cholecystokinin (CCK) slows gastric emptying, stimulates gallbladder contraction, and plays a role in regulating appetite. Overproduction can lead to symptoms like nausea, bloating, and right upper quadrant pain.

Vasoactive intestinal peptide (VIP) generally promotes gastric motility by relaxing smooth muscles. Excessive VIP can cause watery diarrhea, hypokalemia (low potassium), and achlorhydria (lack of stomach acid).

Bicarbonate is secreted by the pancreas and neutralizes stomach acid, protecting the gastric lining. Problems with bicarbonate secretion can lead to gastritis or ulcers, while excess bicarbonate can cause alkalosis and digestive discomfort.

Hormones are chemical messengers that regulate various bodily functions. They are classified into four classes: peptides, steroids, amines, and eicosanoids, each with their unique synthesis, storage, secretion, and metabolism.

The half-life of a hormone is the time it takes for its concentration in the bloodstream to decrease by half. Longer half-life means a hormone will stay in the bloodstream for a longer time.

The phase responsible for the actual expulsion of the fetus from the mother's body.

A hormone produced by the placenta that helps prepare the uterus for labor and delivery.

A hormone produced by the placenta that is crucial for early pregnancy maintenance. It is primarily secreted by the trophoblasts.

A temporary organ that forms during pregnancy, acting as an endocrine gland. It secretes hormones crucial for the functioning of the pregnancy and development of the fetus.

This hormone is produced in large amounts during pregnancy. It has a major effect on milk production.

A hormone produced by the kidneys, primarily regulated by plasma calcium, phosphate, and parathyroid hormone (PTH) levels. Its production is increased when plasma calcium is low, plasma phosphate is low, or PTH is high.

Enzymes that are essential for vitamin D synthesis and activation. They are found in a number of organs, including the liver, the kidneys, and the skin.

A hormone that increases calcium and phosphate absorption in the intestines and kidneys, as well as bone resorption. Its action is stimulated by low plasma calcium levels.

It increases calcium and phosphate absorption in the intestines and kidneys. It also promotes bone resorption, leading to mineralization of new bone. Its action is stimulated by low plasma calcium levels.

A hormone that decreases blood calcium by inhibiting bone resorption from the bones. Its action is stimulated by elevated plasma calcium levels.

A genetic disorder characterized by mutations in the calcium-sensing receptor (CaSR) in the parathyroid gland, leading to hypercalcemia, hypocalciuria, and normal or slightly elevated phosphate levels.

A receptor found primarily in the parathyroid gland that is responsible for sensing extracellular calcium levels. Its function is vital for regulating parathyroid hormone (PTH) secretion.

A hormone produced by the posterior pituitary gland that increases water reabsorption in the kidneys, leading to concentrated urine and decreased urine volume. It also has vasoconstrictive effects, helping regulate blood pressure.

Renin is an enzyme released by the kidneys that initiates the renin-angiotensin-aldosterone system (RAAS).

The juxtaglomerular apparatus (JGA) is a specialized structure within the kidney where the afferent arteriole and the distal convoluted tubule come close together. It plays a crucial role in regulating blood pressure by sensing sodium levels and releasing renin.

Angiotensinogen is a precursor protein synthesized by the liver, which is converted by renin into Angiotensin I.

Angiotensin-Converting Enzyme (ACE) is an enzyme that converts Angiotensin I into Angiotensin II. ACE is primarily found in the lungs.

Angiotensin II is a potent vasoconstrictor that increases blood pressure. It also stimulates the release of aldosterone from the adrenal glands, which promotes sodium reabsorption in the kidneys.

Aldosterone is a hormone produced by the adrenal glands that promotes sodium reabsorption in the kidneys, leading to increased blood volume and blood pressure.

Constriction of the afferent arteriole reduces both renal blood flow (RBF) and glomerular filtration rate (GFR) but does not affect the filtration fraction (FF).

Changes in glomerular capillary pressure directly impact GFR, RBF, and FF. Increased pressure leads to increased filtration and vice versa.