11_Urinary System.pptx

Urinary System Chapter 22, Human Anatomy (LibreTexts) “Kidney Cross Section” by Holly Fischer is licensed under CC BY 3.0 Functions of the Urinary System • Filter waste out of bloodstream: produces urine from waste • Store and excrete urine • Regulate blood volume and, indirectly, blood pressure:...

Urinary System Chapter 22, Human Anatomy (LibreTexts) “Kidney Cross Section” by Holly Fischer is licensed under CC BY 3.0 Functions of the Urinary System • Filter waste out of bloodstream: produces urine from waste • Store and excrete urine • Regulate blood volume and, indirectly, blood pressure: controls how much water is in the blood; level of water related to blood pressure • Regulate production of erythrocytes if oxygen levels are low • Regulate ion balance and acid-base balance in blood Organs of the Urinary System • Kidneys filter blood and produce urine • Urinary tract: • Ureters carry urine to urinary bladder • Urinary bladder stores urine • Urethra expels urine Kidneys: Location • Retroperitoneal organ • Posterior abdominal wall at the level of the 12th rib • Protected by the ribs, muscles, and fats • Left kidney is slightly higher than the right kidney because the liver is in the way • Adrenal gland sits on top of kidney Kidney Position in Abdomen “Kidney Position in Abdomen” by OpenStax is licensed under CC BY 3.0 Kidneys: External Gross Anatomy • Renal fascia: Anchors the kidney in place • Renal fat pad: Cushions and protects kidney • Renal capsule: Dense irregular connective tissue; protects and holds shape of kidney • Hilum: On the medial border; entry and exit site for: blood vessels (renal artery and vein), lymphatic vessel, nerves, ureters Kidneys: Internal Gross Anatomy - 1 Renal cortex: outer region Renal medulla: inner region "2610 The Kidney" by OpenStax College is licensed under CC BY 3.0 Kidneys: Internal Gross Anatomy - 2 Renal lobes: smaller triangular sections that include the followings (from outer to inner): • Section of renal cortex • Renal pyramid: triangular sections in medulla, separated by columns • Renal columns: in both cortex and medulla, divide lobes "2610 The Kidney" by OpenStax College is licensed under CC BY 3.0 • Kidneys: Internal Gross Anatomy - 3 Minor calyx: space adjacent to renal papilla Major calyx: merging of 2 or more minor calyces Renal pelvis: merging of all major calyces, willby OpenStax College is licensed under CC BY 3.0 "2610 The Kidney" Arterial Blood Flow through the Kidneys • Renal artery (starting point) • Segmental artery • Interlobar artery • Arcuate artery • Interlobular artery • Afferent arteriole • Glomerulus (inside Bowman’s capsule): set of fenestrated capillaries where blood filtration happens (no gas exchange) • Efferent arteriole • Peritubular capillaries and Vasa recta: set of capillaries in the cortex and in the medulla, respectively, where gas and nutrients exchange happens. Venous Blood Flow through the Kidneys • Venule • Interlobular vein • Arcuate vein • Interlobar vein • Renal vein • Same names as arteries without the segmental ones. Blood Flow in the Kidney Vasa recta “Blood Flow in the Kidney” by OpenStax is licensed under CC BY 3.0 Kidneys: Microscopic Anatomy • Nephrons are the filtration units of the kidneys. They form urine by filtering blood through a series of tubes, reabsorbing and secreting substances as needed by the body. • Part of the nephron is in the cortex and part in the medulla. • Made by the following tubular parts: • Renal corpuscle = glomerulus + glomerular capsule • Proximal convoluted tubule (PCT) • Nephron Loop (or Loop of Henle): descending limb and ascending limb • Distal convoluted tubule (DCT) Nephron Anatomy • "2611 Blood Flow in the Nephron" by OpenStax College is licensed under CC BY 3.0 / Labeled added by Chiara Mazzasette Nephron: Renal Corpuscle • Glomerulus is a set of fenestrated capillaries surrounded by glomerular capsule. Podocytes are cells that sit on the capillaries and extend pedicels leaving gaps to regulate filtration of liquid. • Lots of liquid (but not cells) can pass through it and into the glomerular capsule which collects the liquid. Renal Corpuscle Image (a) “Juxtaglomerular Apparatus and Glomerulus” by OpenStax is licensed under CC BY 3.0. (b) Micrograph provided by the Regents of University of Michigan Medical School © 2012. Nephron: PCT, DCT and Nephron Loop • Proximal Convoluted Tubule and Distal Convoluted Tubule: tortuous tubes lined with simple cuboidal epithelium with microvilli. • Between proximal and distal convoluted tubule, there is Nephron Loop consisting of a descending limb and ascending limb. Nephron Loop is lined with simple cuboidal epithelium except for the U-turn that is lined with simple squamous epithelium. • In order, the filtrated liquid goes through the glomerular capsule, proximal convoluted tubule, descending limb of nephron loop, ascending limb of nephron loop and distal convoluted tubule. Afterwards, liquid is collected in Collecting Duct. Collecting Duct • NOT part of the nephron • Continuous with DCT • Multiple DCT will empty into one collecting duct • Multiple collecting duct will empty to minor calyx at renal papilla, which will in turn empty in major calyx and renal pelvis. Urinary Tract • From renal pelvis, urine is funneled into urinary tract. • Organs: • Ureters • Urinary bladder • Urethra • Functions: transport, store and excrete urine Ureters • 2 Retroperitoneal tubes connecting kidneys to urinary bladder • Continuous with renal pelvis • Lined with mucosa with transitional epithelium that stretches to accommodate fluid volume and goblet cells to produce mucus • Longitudinal and circular smooth muscles for peristalsis to move urine to urinary bladder • Adventitia with collagen and fats to anchor it to the posterior abdominal wall Ureter Micrograph provided by the Regents of the University of Michigan Medical School © 2012. “Ureter” by OpenStax is licensed under CC BY 3.0 Urinary Bladder • Partially retroperitoneal w/ peritoneum covering the dome superiorly • Receives urine from 2 ureters • Held in place by median umbilical ligament • Rugae inside the bladder • Area bordered by ureteral openings and neck of urinary bladder is called trigone • Mucosa with transitional epithelium • Muscularis has 3 layers of smooth muscle called detrusor muscle that crisscrosses to force urine out and distend as urine accumulates Urinary Bladder Micrograph provided by the Regents of the University of Michigan Medical School © 2012. “Bladder” by OpenStax is licensed under CC BY 3.0 Urethra • Starts at trigone of bladder • Upper region has transitional epithelium • Lower region has nonkeratinized stratified squamous epithelium • 2 sphincters: internal urinary sphincter (superior, involuntary) and external urinary sphincter (inferior, voluntary). Male vs Female Urethra • Female Urethra: • 4 cm in length • Between clitoris and vagina • More urinary tract infection • Male Urethra • 20 cm in length • Passes through prostate • 3 parts: • Prostatic urethra • Membranous urethra • Spongy urethra Female Urethra “Female and Male Urethras” by OpenStax is licensed under CC BY 3.0 Male Urethra “Female and Male Urethras” by OpenStax is licensed under CC BY 3.0 Clinical Anatomy: UTIs • Urinary Tract Infections (UTIs) are common infections that happen when bacteria, often from the skin or rectum, enter the urethra, and infect the urinary tract. The infections can affect several parts of the urinary tract, but the most common type is a bladder infection (cystitis). • Kidney infection (pyelonephritis) is another type of UTI. They’re less common, but more serious than bladder infections. UTI "Bladder Infection" by BruceBlaus is licensed under CC BY-SA 4.0 Clinical Anatomy: Kidney Stones • Kidney stones (also called renal calculi, nephrolithiasis or urolithiasis) are hard deposits made of minerals and salts that form inside your kidneys. • Diet, excess body weight, some medical conditions, and certain supplements and medications are among the many causes of kidney stones. • Kidney stones can affect any part of your urinary tract — from your kidneys to your bladder. Often, stones form when the urine becomes concentrated, allowing minerals to crystallize and stick together. • Depending on the situation, the patient may need nothing more than to take pain medication and drink lots of water to pass a kidney stone. In other instances — for example, if stones become lodged in the urinary tract, are associated with a urinary infection or cause complications — surgery or shock waves may be needed. Kidney Stones "A man with Kidney Stones" by https://www.myupchar.com/en is licensed under CC BY-SA 4.0 Clinical Anatomy: Kidney Transplant • A kidney transplant is a surgical procedure to place a healthy kidney from a living or deceased donor into a person whose kidneys no longer function properly. • When your kidneys lose this filtering ability, harmful levels of fluid and waste accumulate in your body, which can raise your blood pressure and result in kidney failure (end-stage kidney disease). End-stage renal disease occurs when the kidneys have lost about 90% of their ability to function normally. • Only one donated kidney is needed to replace two failed kidneys, making living-donor kidney transplantation an option. In most cases the barely functioning existing kidneys are not removed, as removal has been shown to increase the rates of surgical morbidity. Therefore, the kidney is usually placed in a location different from the original kidney. Kidney Transplant "Kidney Transplant" by BruceBlaus is licensed under CC BY-SA 4.0