Urinary System Functions and Kidney Structure

Kidneys filter blood, produce urine, and regulate blood pressure and volume.

Nephrons are located in the cortex of the kidney.

Blood flows from the renal artery to the glomerulus, then to the peritubular capillaries and back to the renal vein.

Antidiuretic hormone (ADH) increases water reabsorption in the collecting ducts.

Excess uric acid forms crystals in joints (like the big toe), causing gout.

Filtrate flows from glomerular capsule to proximal tubule, loop of Henle, distal tubule, collecting duct, and renal pelvis.

Ureters enter bladder obliquely, preventing urine backflow.

Higher blood pressure raises glomerular pressure, leading to a faster filtration rate. Lower pressure does the opposite.

Aldosterone increases sodium reabsorption, potassium excretion, and water retention.

Renal clearance is the speed at which the kidneys remove a substance from the blood.

Filtration flows through the proximal convoluted tubule, loop of Henle, distal convoluted tubule, and collecting duct.

Regulates blood pressure and filtrate by releasing renin, activating the RAAS.

Concentrates urine by creating an osmotic gradient in the medulla of the kidney.

Glomerular filtrate is essentially plasma without large proteins and cells.

Conscious control inhibits the micturition reflex at the external urethral sphincter.

Epithelial cells have microvilli to increase the surface area for reabsorption.

Filtration is the primary purpose of glomerular capillaries.

Reabsorption and secretion occur in these capillaries.

Secreted into distal convoluted tubule and collecting ducts for acid-base balance.

Water channels (aquaporins) form in response to ADH in the collecting ducts.

A hormonal pathway that regulates blood pressure by controlling sodium and water balance.

Aldosterone, a hormone released by the adrenal glands, increases sodium reabsorption in the kidneys, leading to water retention and potassium excretion.

RAS activation increases aldosterone, which promotes sodium reabsorption and potassium excretion, ultimately maintaining blood pressure and electrolyte balance.

Gastric band placement can reduce stomach capacity, possibly affecting stretch receptor signals and altering thirst mechanisms.

The difference between hydrostatic pressure inside and outside capillaries drives fluid movement.

Diuretics increase urine production by reducing sodium reabsorption in the kidneys, thereby decreasing blood volume and pressure.

Diuretics increase urine output by preventing the kidneys from reabsorbing sodium, which then leads to more water being excreted.

The kidneys filter waste products from the blood, produce urine, and regulate blood pressure and volume.

The glomerulus is a network of capillaries within the kidney that filters blood to form urine.

The nephron is the functional unit of the kidney responsible for filtering blood, producing urine, and regulating blood pressure.

Water movement across cell membranes depends on osmotic gradients created by electrolyte concentrations. Electrolytes regulate fluid distribution between cells and the space surrounding them.

Increased plasma osmolality (more concentrated blood), decreased blood volume/pressure, or the hormone angiotensin II stimulate the thirst center in the brain.

Adequate water intake, decreased osmolality (less concentrated blood), and stretch receptors in the stomach and intestines signal to stop drinking.

High in sodium, chloride, and bicarbonate ions; low in potassium and magnesium.

High in potassium, magnesium, and phosphate ions; low in sodium and chloride.

Loss of electrolytes (sodium, potassium), metabolic alkalosis (pH too high) due to lost stomach acid, and dehydration.

Bicarbonate, phosphate, and proteins neutralize excess acids or bases, maintaining pH balance.

Hemoglobin and plasma proteins bind hydrogen ions to help regulate pH.

Act immediately to neutralize excess acids or bases, maintaining pH homeostasis before respiratory or renal systems kick in.

Ketones from fat metabolism can cause ketoacidosis, lowering blood pH and leading to metabolic acidosis.