Urinary System Overview

Sodium actively moves from tubule cells to interstitial fluid, then to peritubular capillaries. This creates a low sodium concentration in the tubule cells which allows sodium to diffuse back in; this process is coupled with glucose and amino acid transport into tubule cells, and accompanied by chloride for balanced charge.

Certain substances are actively or passively moved from the peritubular capillaries back into the nephron, including penicillin, pesticides, preservatives, hydrogen ions, urea, ammonium, potassium, & cocaine.

High blood pressure forces fluid and small molecules from the glomerulus into the glomerular capsule, leaving behind blood cells and large proteins.

Antidiuretic hormone (ADH) affects the permeability of the collecting and distal tubules, controlling whether urine is dilute or concentrated to manage excess water.

A high sodium intake leads to increased water reabsorption, higher blood volume, and consequently, higher blood pressure.

The urinary system filters waste from the blood, excreting water, nitrogenous wastes, and other solutes.

The nephron is the basic functional unit of the kidney and filters blood, reabsorbing essential substances. 180 liters of Blood fluid potentially enter the nephrons daily.

Nutrients and water are reabsorbed back into the blood through peritubular capillaries.

Urea, uric acid, and excess ions like sodium and potassium are excreted in urine.

A cluster of capillaries in the nephron where blood filtration begins, high pressure helps filtration.

The cup-shaped structure at the start of the nephron that catches the filtered fluid from the glomerulus.

The liver converts ammonia (from protein breakdown) to urea, which is then filtered by the kidneys.

Antidiuretic hormone (ADH) regulates the concentration of urine. High ADH leads to more water retention, creating concentrated urine. Low ADH results in more water loss, producing dilute urine.

Substances like alcohol and caffeine interfere with ADH secretion or sodium reabsorption, promoting water loss through urine. This can be beneficial in treating high blood pressure.

Urine flows from the kidneys (renal pelvis) to the ureters, bladder, and finally, urethra for excretion.

The urinary system has two sphincters: an internal (smooth muscle) and external (skeletal muscle) sphincter. The internal sphincter is involuntary, while the external is under conscious control.

Kidney stones form from crystallized minerals (uric acid, calcium, magnesium). These can block the ureters, causing pain during passage and potential damage to nephrons.

Kidney failure occurs when the kidneys lose their ability to effectively filter waste, often due to other medical conditions like high blood pressure or diabetes.

Urinary tract infections (UTIs) are infections that can start in the urethra and spread to the bladder and even kidneys—caused by bacteria entering the urinary system.

Sodium actively moves out of tubule cells into the interstitial fluid, then into peritubular capillaries. This creates a lower sodium concentration in the tubule cells, allowing sodium to passively diffuse back in. This process is coupled with glucose and amino acid transport into the tubule cell, and accompanied by chloride ions to maintain electrical balance.

Certain substances actively or passively move from the peritubular capillaries back into the nephron. This includes things like penicillin, some pesticides and preservatives, hydrogen ions, urea, ammonium, potassium ions, cocaine, and marijuana.

A high sodium diet leads to increased water reabsorption back into the peritubular capillaries. This results in greater retention of water in blood vessels, leading to higher blood pressure.

The kidneys play a crucial role in regulating the body's pH by secreting hydrogen ions into the nephron.

The urinary system filters waste products from the blood, forming urine. It excretes water, nitrogenous waste like urea, and other excess solutes like salts.

The four main organs are the Kidneys, Ureters, Urinary Bladder, and Urethra.

Urine is produced in the nephrons, which are located in the medulla of the kidneys.

1. Filtration: Blood pressure forces fluid and small molecules from the glomerulus into the glomerular capsule. 2. Reabsorption: Essential substances (like water, glucose, and amino acids) are reabsorbed back into the blood. 3. Secretion: Waste products and excess substances are moved from the blood into the nephron for excretion.

The glomerulus is a cluster of capillaries where filtration occurs. It has high blood pressure that forces fluid and small molecules out of the blood.

Tubular reabsorption is when essential substances, like water, glucose, and amino acids, are reabsorbed back into the blood from the nephron.

The collecting duct plays a key role in regulating urine concentration by controlling the amount of water reabsorbed back into the body.

Common waste products include urea, uric acid, excess sodium and potassium ions, and excess water-soluble vitamins.

Diuretics are medications that promote water loss through urination. They work by interfering with ADH secretion or sodium reabsorption in the kidneys.

Two sphincters control urine release. The internal sphincter is involuntary, made of smooth muscle. The external sphincter is under conscious control, made of skeletal muscle. The external sphincter lets you hold your urine, but the internal sphincter relaxes when your bladder is full.

Kidney stones form when minerals (uric acid, calcium, magnesium) crystallize in the renal pelvis. They can block the ureters, causing pain and potential damage to the kidneys.

UTIs occur when bacteria enter the urethra and spread to the bladder and even the kidneys. This can cause painful urination, frequent urges to urinate, and sometimes even fever.