Overview of the Urinary System and Its Functions

Kidneys

Filter waste out of our bloodstream, producing urine

Renal arteries

Carry unfiltered blood into the kidneys to be filtered

Renal veins

Carry filtered blood away from the kidneys and to the inferior vena cava

Renal cortex

Superficial, outer layer of the kidneys

Renal medulla

Deeper portion of the kidneys

Nephron

The smallest functional unit of our kidneys

Calyces

Singular = calyx

Renal pelvis

Funnel-shaped

Ureters

Narrow tubes

Urinary Bladder

Muscular sac that stores urine until urination

Urethra

Tube that drains urine from the bladder out of the body

Nephrons

Tiny tubes inside your kidneys that filter your blood to produce urine

Urine

Made of water, urea, and other waste products

Renal artery

Delivers unfiltered blood to the nephron; splits into the glomerulus

Glomerulus

A tight ball of capillaries filled with unfiltered blood from the renal artery

Bowman's capsule

The first part of the nephron; cup-shaped; surrounds the glomerulus

Renal tubule

Consists of 3 parts: proximal convoluted tubule; loop of Henle; distal convoluted tubule

Proximal convoluted tubule

Part of the renal tubule

Loop of Henle

Part of the renal tubule

Distal convoluted tubule

Part of the renal tubule

Renal vein

Removes filtered blood from the nephron back to the body

Collecting duct

Collects urine from many nephrons

Filtration

Removing waste from the blood in the Bowman's capsule to create filtrate

Filtrate

About 20% of the blood's plasma that enters the Bowman's capsule

Reabsorption

Putting important materials (ex. Water & nutrients) in the filtrate back into the bloodstream

Secretion

Last chance to diffuse waste from the blood into the filtrate/urine

Filtration process

Pressure on the blood in the capillaries of the glomerulus causes water and small waste molecules to leave the glomerulus and enter the Bowman's capsule

Reabsorption locations

Occurs in the proximal convoluted tubule & loop of Henle all the time; occurs in the distal convoluted tubule if we are dehydrated

Daily filtrate removal

In 24 hours, we remove 180 L of filtrate from our blood