Renal System and Urinary Anatomy

Students will distinguish structures and functions of the urinary system
Understand differences between male and female urinary tracts
Describe the blood flow through the kidneys
Understand nephron structures and their functions
Learn fluid transportation through the urinary system
Understand urine formation, composition, and qualities
Recognize clinical implications of abnormal urinalysis and urinary tract infections (UTIs)

Urine: Liquid waste produced by the kidneys.
Urea: A component of urine, formed by the breakdown of proteins in food.
Renal hilus: External anatomy with medial indentation of the kidney.
Renal capsule: Fibrous external covering of the kidney.
Adrenal gland: Endocrine gland on the kidney's superior surface.
Cortex: Most superficial region of internal kidney anatomy.
Medulla: Inner kidney region, deeper than the cortex.
Renal pyramids: Triangular regions of the medulla, striped appearance due to urine-collecting tubules.
Renal calyx: Cup-shaped area collecting urine from the renal pyramids.
Renal artery: Vessel carrying blood into the kidneys from the descending aorta.

Renal vein: Carries blood from the kidneys to the inferior vena cava.
Nephron: Filtering unit of the kidneys; each kidney contains over 1 million nephrons.
Glomerulus: A ball of capillaries in the nephron where blood filtration occurs.
Renal tubule: Twisted, coiled tube of the nephron that connects to collecting ducts.
Bowman's capsule: Cup-shaped end of the renal tubule surrounding the glomerulus.
Filtration: Nonselective process where blood pressure pushes fluids and solutes out into the glomerular capsule.
Filtrate: The fluid in the renal tubule post-filtration.
Reabsorption: The process where useful substances like water, glucose, and ions are moved back into the blood.
Secretion: Active transport of substances from blood into the tubule for urine formation.
Afferent arteriole: Brings blood into the glomerulus.
Efferent arteriole: Drains blood from the glomerulus into peritubular capillaries.

Kidneys: Filter blood, remove waste, convert filtrate into urine.
Ureters: Transport urine from kidneys to urinary bladder.
Bladder: Expandable muscular sac storing up to 1 L of urine.
Urethra: Eliminates urine from the body; longer in males than in females.
Functions: Elimination of metabolic wastes, regulation of ion levels and acid-base balance, regulation of blood pressure, and formation of erythropoietin.

Hilum: Vessels and nerves connect to the kidney.
Renal artery: Transports blood to the kidney; renal vein filters and exits blood from the kidney.
Renal cortex: Outer functional tissue; renal medulla: inner functional tissue.

Components: Consists of renal corpuscle (glomerulus and Bowman's capsule) and renal tubule (PCT, nephron loop, DCT).
Juxtaglomerular Apparatus: Regulates blood filtrate formation and blood pressure; contains granular cells that produce renin.

Urethritis: Infection begins in urethra.
Cystitis: Infection spreads to the bladder.
Pyelonephritis: Infection spreads to the kidneys.
Symptoms: Painful urination, frequent urination, pressure, back pain, nausea.

Mechanisms: Activated by juxtaglomerular complex, leading to renin production.
Renin activates angiotensin I, converted to angiotensin II, which constricts arterioles and increases aldosterone secretion, raising blood pressure and improving glomerular filtration rate (GFR).

Ureters: Conduct urine from kidneys to the bladder; their mucosa is distensible to store urine.
Urinary bladder: Expandable container for urine.
Urethra: Conducts urine out of the body; has internal (involuntary) and external (voluntary) sphincters.
Male Urethra: Passageway for urine and semen, consists of three segments: prostatic, membranous, and spongy urethra.

Understanding the urinary system's anatomy, functions, and clinical aspects is crucial for identifying and treating conditions related to renal health.