General Introduction Excretory Organs Lungs Liver Skin Kidneys

Functions of the Urinary System A. Conserves Valuable Nutrients B. Separates/Eliminates Wastes C. Regulates Blood Volume and Blood Pressure D. Regulates Ion Levels In Plasma E. Regulates Blood pH

Organs of the Urinary System Kidneys Ureters Urinary bladder Urethra

Kidneys: Location Retroperitoneal

Kidneys: Structure Renal capsule Several layers of fat

Kidneys: Structure 2 layers: Cortex Medulla

Kidneys: Structure Calyx Renal Pelvis Renal Hilus

Nephron Glomerulus Bowman’s capsule Proximal convoluted tubule Loop of Henle Distal convoluted tubule

Glomerulus and Bowman’s Capsule

Bowman’s Capsule Podocytes Pedicels Filtration Slits

Collecting Duct

Summary of Flow of Fluid Glomerular capsule Proximal convoluted tubule Loop of Henle Distal convoluted tubule Collecting duct Renal papilla Calyx Renal pelvis Ureter Bladder Urethra Out of body

Kidneys: Function Filter wastes and produce urine by: Filtration Reabsorption Secretion

Ureters: Structure Mucosa: epithelium Muscularis: two layers Adventitia: connective tissue a = lumen b= mucosa c = circular muscle layer d = longitudinal muscle layer e = adventitia

Ureters: Structure

Ureters: Function Carry urine from the kidneys to the urinary bladder

Urinary Bladder: Structure Mucosa (rugae) Muscularis (Detrusor muscle) Adventitia

Urinary Bladder: Function Stores and expels urine

Urethra: Structure Mucosa Muscularis Adventitia

Urethra: Function Transports urine from bladder to outside body

Female Urethra

Male Urethra Prostatic Membranous Spongy/Penile

Blood Flow Through the Kidney (A RAGE PRV I) A bdominal Aorta R enal Artery A fferent Arterioles G lomerular Capillaries E fferent Arterioles P eritubular Capillaries V asa Recta R enal Vein I nferior Vena Cava

Tubular Section of Nephron Figure 23.4b

Regulation of Water and Electrolytes The body gains water through 2 processes 1. Absorption 2. Metabolism

Water Loss Urinary System Lungs Skin Intestines

Cardiac Output and Renal Function Cardiac Output = Stroke volume (ml)  Heart Rate (beats/min)

Hormones that Regulate Electrolyte Balance Antidiuretic Hormone (ADH or vasopressin) Renal-Angiotensin Aldosterone Erythropoetin Atrial Natriuretic Hormone

Antidiuretic Hormone (ADH) Released in response to increase in concentration of electrolytes in blood or a fall in blood volume or pressure ADH decreases the amount of water lost at the kidneys, which reduces the concentration of electrolytes. ADH also constricts peripheral blood vessels, which helps to increase blood pressure.

Renin-Angiotensin-Aldosterone The enzyme renin is released by kidney in response to a decrease in blood volume, blood pressure or both. Renin starts chain of reactions that lead to formation of hormone in liver called angiotensin II. AG II stimulates adrenal cortex to make aldosterone and posterior pituitary gland to make ADH. Both inhibit salt and water loss at kidneys resulting in increased blood volume and blood pressure.

Erthyropoietin Released by kidneys in response to low O2 levels Stimulates production of RBCs in bone marrow. Increase number of RBCs elevates blood volume.

Atrial Natriuretic Hormone Cells in right atrium make this hormone in response to increased blood volume. Stimulates loss of sodium ions and water at the kidneys Inhibits renin release Inhibits secretion of ADH and aldosterone Result is reduced blood volume and blood pressure.