Renal Physiology Quiz

<p>60 times (C)</p> Signup and view all the answers

<p>Uric acid (A)</p> Signup and view all the answers

<p>Sodium ions (A)</p> Signup and view all the answers

<p>Excretion of metabolic products (B)</p> Signup and view all the answers

<p>Detect sodium chloride concentration (C)</p> Signup and view all the answers

<p>Excretion of metabolic waste products (A)</p> Signup and view all the answers

<p>60 times (D)</p> Signup and view all the answers

<p>O2 (B)</p> Signup and view all the answers

<p>1200 mOsm (A)</p> Signup and view all the answers

<p>Performing specific modifications to fluid (C)</p> Signup and view all the answers

<p>Blood volume and cardiac output (B)</p> Signup and view all the answers

<p>0.5 L (D)</p> Signup and view all the answers

<p>Urine containing substances for homeostatic balance (B)</p> Signup and view all the answers

<p>Na+ (D)</p> Signup and view all the answers

<p>Secretion of erythropoietin (A)</p> Signup and view all the answers

<p>Hypothalamus (A)</p> Signup and view all the answers

<p>They shrink (C)</p> Signup and view all the answers

<p>Increases water permeability (C)</p> Signup and view all the answers

<p>Stimulates their translocation to the membrane (C)</p> Signup and view all the answers

<p>Decreased ADH release (B)</p> Signup and view all the answers

<p>Increased water reabsorption (C)</p> Signup and view all the answers

<p>It decreases from 600 mOsm/L to 300 mOsm/L (D)</p> Signup and view all the answers

<p>Reduces sodium reabsorption (C)</p> Signup and view all the answers

<p>Promote Na+ and water reabsorption (A)</p> Signup and view all the answers

<p>Angiotensin II action (A)</p> Signup and view all the answers

<p>Constricts efferent arteriole (B)</p> Signup and view all the answers

<p>Promotes K+ secretion (C)</p> Signup and view all the answers

<p>Renin-angiotensin-aldosterone (RAAS) system (B)</p> Signup and view all the answers

<p>Increases urine concentration (B)</p> Signup and view all the answers

<p>Na-K ATPase (C)</p> Signup and view all the answers

<p>Increased blood pressure over time (B)</p> Signup and view all the answers

<p>Increases water excretion (D)</p> Signup and view all the answers

<p>It increases the resistance of the afferent arteriole by constriction. (B)</p> Signup and view all the answers

<p>Nitric oxide (A), Prostaglandin (C)</p> Signup and view all the answers

<p>Increased intracellular Ca2+ in smooth muscle cells. (B)</p> Signup and view all the answers

<p>By influencing afferent arteriolar resistance based on NaCl and flow. (B)</p> Signup and view all the answers

<p>Decreased NaCl concentration sensed by the macula densa. (C)</p> Signup and view all the answers

<p>It constricts the efferent arterioles. (C)</p> Signup and view all the answers

<p>Decreased renin secretion. (A)</p> Signup and view all the answers

<p>They increase smooth muscle contraction in the afferent arterioles. (C)</p> Signup and view all the answers

<p>Decreases GFR due to reduced blood flow (A)</p> Signup and view all the answers

<p>Decreases GFR by constricting renal arterioles (D)</p> Signup and view all the answers

<p>Myogenic autoregulation (A)</p> Signup and view all the answers

<p>Decreased GFR due to reduced renal blood flow (C)</p> Signup and view all the answers

<p>Myogenic autoregulation (D)</p> Signup and view all the answers

<p>Afferent and efferent arteriole feedback mechanisms (B)</p> Signup and view all the answers

<p>Urine production increases significantly (B)</p> Signup and view all the answers

<p>They constrict both afferent and efferent arterioles (A)</p> Signup and view all the answers

<p>Arterial pressure (A)</p> Signup and view all the answers

<p>Contracts smooth muscle cells in arterioles (A)</p> Signup and view all the answers

The kidneys filter approximately 20% of blood volume daily resulting in 180 liters of filtrate produced per day.

The kidneys regulate the volume and composition of body fluids by controlling the excretion of water and electrolytes.

The kidneys maintain blood pressure by helping to regulate blood volume and electrolyte balance.

The kidneys regulate red blood cell production by producing erythropoietin, a hormone that stimulates red blood cell production by the bone marrow.

The kidneys regulate calcium and phosphate balance by activating vitamin D, which is essential for calcium absorption in the gut.

The kidneys regulate acid-base balance by secreting hydrogen ions into the urine and reabsorbing bicarbonate.

Each nephron is a functional unit of the kidney comprised of a glomerulus and a tubule.

The glomerulus is a network of capillaries in the nephron where filtration occurs.

The tubules are the long, narrow tubes in the nephron where reabsorption and secretion occur.

The kidneys concentrate urine to conserve water by creating a concentration gradient in the renal medulla.

The renal corpuscle is the initial filtering unit in the kidney, composed of Bowman's capsule and the glomerulus. It's responsible for filtering blood and producing a fluid called filtrate.

The proximal convoluted tubule is the first part of the renal tubule, a long and coiled structure in the kidney. It reabsorbs most of the water, electrolytes, and nutrients from the filtrate.

The filtration process in the kidney selectively allows certain substances, like water, waste products, and electrolytes, to pass from the blood into the nephron, while blocking larger molecules like proteins.

Reabsorption is the process where essential substances, such as glucose, amino acids, and water, are taken back from the filtrate in the renal tubules and return to the bloodstream.

Secretion is an active process where the kidney adds specific substances to the filtrate in the renal tubules, including waste products and excess ions.

The glomerular filtration rate (GFR) is a measure of how well the kidneys are filtering blood. It indicates the volume of blood filtered by the kidneys per minute.

Urea, creatinine, and uric acid are waste products produced by the body's metabolic processes and are eliminated through urine. They are poorly reabsorbed by the kidneys.

The body filters a large volume of fluid (about 60 times the plasma volume) daily. This is necessary for maintaining proper blood volume, electrolyte balance, and removal of waste products.

The ability of renal blood vessels to resist stretching with increased arterial pressure.

The efferent arteriole, when slightly constricted, causes an increase in the GFR. However, if strongly constricted, a decrease in GFR occurs due to reduced renal blood flow causing a build-up of pressure.

Afferent arteriole resistance is inversely proportional to GFR. This means that as afferent arteriole resistance increases, GFR decreases.

The macula densa feedback mechanism is a system in the kidney that helps regulate GFR by adjusting the resistance of both afferent and efferent arterioles.

The macula densa detects alterations in fluid composition within the distal tubule, initiating signals to adjust GFR.

The juxtaglomerular complex is a specialized structure in the kidney that plays a key role in the macula densa feedback mechanism.

The "myogenic mechanism" helps maintain a consistent renal blood flow and GFR. When the arterial pressure increases, the vessel walls stretch, causing Ca2+ to enter the smooth muscle cells which contracts, preventing an increase in renal blood flow and GFR.

The sympathetic nervous system (SNS) activation decreases GFR by constricting renal blood vessels. Mild SNS activation has little effect on GFR, while severe SNS activation only has effects under severe conditions like hemorrhage.

Endothelin, a peptide released by damaged endothelial cells, constricts afferent and efferent arterioles, reducing GFR.

Norepinephrine and epinephrine constrict afferent and efferent arterioles, reducing GFR however, their effects are only prominent under severe conditions.

ADH is produced by neurons in the supraoptic and paraventricular nuclei of the hypothalamus.

Osmoreceptors in the hypothalamus sense changes in blood osmolarity. When ECF osmolarity increases, osmoreceptors shrink.

When osmoreceptors shrink, they signal to the nerve cells in the hypothalamus, leading to the release of ADH.

ADH is released from the posterior pituitary gland into the bloodstream.

ADH increases the permeability of the distal tubules and collecting ducts to water, leading to increased water reabsorption and the production of concentrated urine.

The lack of ADH leads to decreased water permeability in the distal tubules and collecting ducts, resulting in the production of dilute urine.

The countercurrent multiplier system establishes a high osmolarity in the renal medulla, allowing the kidneys to concentrate urine.

In the formation of dilute urine, the interstitial osmolarity gradient is lower than in the formation of concentrated urine.

The macula densa (MD) is a specialized group of epithelial cells located in the distal convoluted tubule (DCT) of the nephron, where it senses changes in the concentration of sodium chloride (NaCl) in the tubular fluid.

The tubuloglomerular feedback (TGF) mechanism is a critical autoregulatory process that ensures stable glomerular filtration rate (GFR) despite fluctuations in blood pressure. This mechanism relies on the macula densa to detect changes in NaCl concentration in the tubular fluid and trigger adjustments in afferent arteriole resistance.

When GFR decreases, there is less NaCl reaching the macula densa cells in the DCT. This triggers a series of events designed to increase GFR back to normal. The MD cells release nitric oxide (NO) and prostaglandin (PGE2), both vasodilators, which relax the afferent arteriole smooth muscle. This increase in afferent arteriole diameter leads to increased blood flow and pressure, ultimately increasing GFR.

When GFR increases, more NaCl reaches the macula densa. This activates the Na-K-2Cl cotransporter, increasing intracellular NaCl concentration. As a result, the MD cells release ATP and adenosine. These bind to purinergic receptors on the afferent arteriole smooth muscle, triggering calcium influx and constriction. This ultimately reduces blood flow and pressure, thereby lowering GFR.

The release of renin is also affected by the TGF mechanism. When GFR is low, the MD cells stimulate renin release from the juxtaglomerular cells. Renin initiates the RAAS (renin-angiotensin-aldosterone system), leading to angiotensin II production, which constricts the efferent arteriole. This helps to maintain glomerular pressure and filtration rate, even when systemic blood pressure is low.

In low GFR, the MD cells release NO and PGE2 leading to dilation of the afferent arteriole, increasing glomerular pressure and filtration rate. Renin release is also stimulated, activating the RAAS system and further increasing GFR.

In high GFR, the MD cells release ATP and adenosine, constricting the afferent arteriole. This reduces glomerular pressure and filtration rate. Renin release is suppressed, further reducing GFR.

Angiotensin II, a powerful vasoconstrictor, acts on peripheral blood vessels, causing rapid narrowing, which increases blood pressure.

Angiotensin II decreases blood flow to the kidneys by constricting the renal arterioles, reducing filtration rate.

Angiotensin II reduces pressure in the peritubular capillaries, causing increased reabsorption of fluid from the renal tubules back into the bloodstream.

Angiotensin II increases sodium and water reabsorption at multiple points along the nephron, including the proximal tubule, Loop of Henle, distal tubule, and collecting ducts.

Angiotensin II stimulates the Na-K ATPase, Na-H exchanger (NHE), and Na-bicarbonate co-transporter in various parts of the nephron, enhancing sodium reabsorption.

Aldosterone, a hormone produced by the adrenal cortex, promotes sodium and water reabsorption, increasing extracellular fluid volume and blood pressure.

Aldosterone's primary site of action is the principal cells of the cortical collecting duct, where it stimulates sodium reabsorption and potassium secretion.

Aldosterone is synthesized from cholesterol through a series of enzymatic conversions, starting with pregnenolone.

Aldosterone increases sodium reabsorption by activating the Na-K ATPase and enhancing sodium permeability in the luminal membrane, leading to slight increases in blood volume and pressure.

The Renin-Angiotensin-Aldosterone System (RAAS) is a crucial pathway for blood pressure regulation, involving the interplay of renin, angiotensin, and aldosterone.