Ch 25, L1a

• Study notes on the urinary system

Urinary System Overview

• Kidneys facilitate urine production.
• Ureters are for transporting urine from the kidneys to the bladder.
• The bladder serves as a storage unit for urine.
• The urethra transports urine outside the body.

Kidney Function

• Kidneys are major excretory organs that maintain the body's internal environment.
• They regulate total water within the body alongside total solute concentration.
• Kidneys regulate ion concentrations in extracellular fluid (ECF).
• Kidneys ensure long-term acid-base balance.
• Kidneys are responsible for excreting metabolic wastes, toxins, and drugs.
• The kidneys produce erythropoietin, which regulates blood pressure and renin, further regulating RBC production.
• Kidneys are able to activate vitamin D.
• Gluconeogenesis is carried out in the kidneys, if needed.

Kidney Location and Anatomy

• Kidneys are retroperitoneal, located in the superior lumbar region.
• Kidneys' location is between T12 and L5.
• The right kidney is positioned lower than the left because it is crowded by the liver.
• The adrenal (suprarenal) gland sit atop each kidney.
• Each kidney is about the size of a large bar of soap.

Kidney Internal Anatomy and Urine Flow

• Urine formation occurs in the renal medulla.
• Urine flows through the renal pyramid, minor calyx, major calyx, renal pelvis, and finally the ureter.

Blood Supply to Kidneys

• Path of blood flow through renal blood vessels is as follows: Aorta, renal artery, segmental artery, interlobar artery, arcuate artery, cortical radiate artery, afferent arteriole, glomerulus (capillaries), efferent arteriole, peritubular capillaries (or vasa recta), cortical radiate vein, arcuate vein, interlobar vein, renal vein, and inferior vena cava.