Kidney and Bladder Anatomy and Physiology

The proximal convoluted tubule is the primary site for selective reabsorption of water, electrolytes, and nutrients from the filtrate back into the bloodstream.

Urinary retention is a condition where the bladder is unable to empty completely due to various causes like nerve damage, obstruction, or muscle dysfunction.

Acute Kidney Injury (AKI) is a sudden decline in kidney function, often characterized by oliguria (reduced urine output). This can occur due to decreased blood flow to the kidneys (prerenal), damage to the kidney tissue (intrarenal), or obstruction of urine flow (postrenal).

Oliguria in AKI is caused by a decrease in glomerular filtration rate (GFR), meaning the kidneys filter less blood, increased reabsorption of water, and sometimes obstruction in the urinary tract, all of which contribute to less urine production.

Urinary tract infections (UTIs) occur when bacteria enter the urinary tract, typically through the urethra, and multiply. Women are more susceptible due to their shorter urethra, making it easier for bacteria to travel from the anus to the bladder. Left untreated, UTIs can progress to pyelonephritis (kidney infection) and even sepsis.

Paired, bean-shaped organs located below the rib cage, responsible for filtering blood and producing urine.

Functional unit of the kidney, responsible for filtering blood and producing urine. Each kidney has approximately 1 to 1.5 million nephrons.

Nephrons located mostly in the renal cortex, with shorter loops of Henle. Responsible for most filtration.

Nephrons with longer loops of Henle extending into the medulla. Crucial for concentrating urine and conserving water.

Network of capillaries at the beginning of the nephron. Filters blood, allowing water, electrolytes, and small molecules to pass through while keeping larger molecules like proteins and blood cells.

Cup-like sac surrounding the glomerulus, collecting filtered substances. It's the first stage of processing urine.

Hollow, muscular organ storing urine before excretion. Its muscle is called the detrusor muscle.

Absence of urine production or less than 50 ml/day. Indicates severe kidney dysfunction or urinary tract obstruction.

Frequent and sudden urge to urinate, hard to control, can lead to incontinence.

Reduced urine output, less than 400 ml/day or 20 ml/hour, can be a sign of kidney problems or dehydration.

Blood in the urine, can be a sign of infection, stones, or even cancer.

Inability to empty the bladder completely, can be acute or chronic, caused by nerve issues, blockages, or weak muscles.

Involuntary leakage of urine during activities increasing pressure, like coughing or lifting.

Production of abnormally large amount of urine, often exceeding 3 liters per day, seen in diabetes.

Prostate gland enlargement, common in older men, causes difficulty urinating, frequent urination, and weak stream.

Infection in any part of the urinary system, includes kidneys, bladder or urethra, symptoms include burning sensation during urination.

A state where the blood pH is too low, often caused by a buildup of acids or loss of bicarbonate.

A state where the blood pH is too high, often caused by an excess of bicarbonate or loss of acids.

The kidneys help restore acid-base balance by increasing reabsorption of bicarbonate and excretion of hydrogen ions.

The kidneys help restore acid-base balance by excreting excess bicarbonate and reducing hydrogen ion secretion.

The lungs increase the rate and depth of breathing (hyperventilation) to expel more CO2, raising the pH.

The lungs decrease the rate and depth of breathing (hypoventilation) to retain more CO2, lowering the pH.

The kidneys play a vital role in maintaining the body's pH by regulating bicarbonate levels and excreting hydrogen ions.

A process where the nephron selectively takes back essential substances like water, electrolytes, and nutrients from the filtered fluid and returns them to the bloodstream.

The nephron removes additional waste products and excess ions from the blood and adds them to the filtered fluid, which eventually becomes urine.

The rate at which the kidneys filter blood, measured in milliliters per minute, typically around 125 ml/min in healthy adults.

The reabsorption of water and solutes that happens regardless of the body's needs, mainly in the proximal convoluted tubule of the nephron.

The adjustable reabsorption of water and solutes based on the body's needs, controlled by hormones like ADH.

A hormone that controls the reabsorption of water in the kidneys, leading to concentrated urine.

A hormone produced by the kidneys in response to low blood pressure or low sodium levels. It helps regulate blood pressure and fluid balance.

A hormone produced by the kidneys that stimulates the production of red blood cells in the bone marrow, crucial for oxygen transport.

A hormone produced by the liver that is converted into angiotensin I by renin, a key player in the renin-angiotensin-aldosterone system (RAAS).

The active hormone in the RAAS, formed from angiotensin I by ACE. It causes vasoconstriction, increases sodium reabsorption, and stimulates the release of aldosterone, ultimately leading to increased blood pressure.

An enzyme primarily found in the lungs that converts angiotensin I into angiotensin II, a crucial step in the RAAS cascade.

A hormone released from the adrenal gland in response to angiotensin II. It increases sodium reabsorption in the distal convoluted tubule, contributing to increased blood pressure.

A negative feedback loop that regulates blood pressure, blood volume, and sodium levels. It is activated when blood pressure or sodium levels are low.

Specialized cells in the afferent arteriole of the nephron that sense changes in blood pressure. They trigger the release of renin, initiating the RAAS.

Sensors located in the macula densa of the distal convoluted tubule that detect changes in sodium levels, contributing to the activation of the RAAS.

A complex system in the body that regulates blood pressure and fluid balance. It is activated when the body detects low blood volume or blood pressure.

Specialized cells in the juxtaglomerular apparatus that detect changes in blood pressure and volume. They act like sensors for the RAAS.

These receptors located in the macula densa monitor sodium levels in the blood. Decreases in sodium trigger the release of renin.

An enzyme produced by the juxtaglomerular cells in the kidney. It converts angiotensinogen to angiotensin I, the first step in the RAAS cascade.

An enzyme produced by the lungs that converts angiotensin I to angiotensin II, the active hormone in the RAAS.

The active hormone in the RAAS. It triggers a cascade of effects to increase blood pressure and volume.

A hormone produced by the adrenal glands in response to angiotensin II. It increases sodium reabsorption in the kidneys.

A hormone produced by the posterior pituitary gland. It increases water reabsorption in the kidneys, concentrating urine.

A process where blood vessels constrict, reducing blood flow. Angiotensin II causes vasoconstriction.

The sympathetic nervous system is activated by angiotensin II, leading to increased heart rate, vasoconstriction, and other 'fight-or-flight' responses.