Urinary system

Urinary system - Urinary (Renal) System EXSS 175 ­ Human...

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Unformatted text preview: Urinary (Renal) System EXSS 175 ­ Human Anatomy The University of North Carolina at Chapel Hill The University of North Carolina at Chapel Hill Outline • • • • • • Overview of urinary system Kidney functions External anatomy of the kidneys Internal anatomy of the kidneys Physiology of urinary system Urine transportation, storage, and elimination The University of North Carolina at Chapel Hill The University of North Carolina at Chapel Hill Renal System • Consists of: • 2 Kidneys • 2 Ureters • 1 Urinary bladder • 1 Urethra • General function: Filter blood and, • Keep necessary fluid and components • Excrete wastes The University of North Carolina at Chapel Hill The University of North Carolina at Chapel Hill Kidneys • “Size of a fist” – 4­5 inches long – 2­3 inches wide – 1 inch thick • Location – Lateral to T12 ­ L3 – Right slightly lower • Retroperitoneal cavity The University of North Carolina at Chapel Hill The University of North Carolina at Chapel Hill Kidney Functions 1. 2. 3. 4. 5. 6. 7. 8. Regulation of blood ionic composition Regulation of blood pH Regulation of blood volume Regulation of blood pressure Maintenance of blood osmolarity Production of hormones Regulation of blood glucose level Excretion of wastes and foreign substances The University of North Carolina at Chapel Hill The University of North Carolina at Chapel Hill Regulation of blood ionic composition • Regulate blood levels of: • Sodium ions (Na+) • Normal: Na+ 135 to 145 milliequivalents per liter • Potassium ions (K+) • Calcium ions (Ca2+) • Chloride ions (Cl­) • Phosphate ions (HPO42­) The University of North Carolina at Chapel Hill The University of North Carolina at Chapel Hill Regulation of blood pH • Excretion • Hydrogen ions (H+) into urine • Conservation • Bicarbonate ions (HCO3­) The University of North Carolina at Chapel Hill The University of North Carolina at Chapel Hill Regulation of blood volume and pressure Fluid Reduction • Conserve vs. eliminate water volume= blood pressure Constriction of blood vessel = blood pressure Vasoconstriction The University of North Carolina at Chapel Hill The University of North Carolina at Chapel Hill Kidney Functions • Maintenance of blood osmolarity • Loss of water and solutes • Production of hormones • Calcitriol • Active form of Vitamin D • Helps with Calcium homeostasis • Erythropoietin • Stimulate production of RBC The University of North Carolina at Chapel Hill The University of North Carolina at Chapel Hill Kidney Functions • Regulation of blood glucose level • Gluconeogenesis • Release glucose into blood • Excretion of waste and foreign substance • Metabolic reaction wastes • Ammonia, urea, bilirubin, creatine, uric acid • Drugs and toxins The University of North Carolina at Chapel Hill The University of North Carolina at Chapel Hill Kidney External Anatomy • Renal Hilus (hilum) – Notch located near the center concavity – Passageway to renal sinus (cavity) • Ureter • Renal artery • Renal vein • Lymphatic vessels • Nervous innervation The University of North Carolina at Chapel Hill The University of North Carolina at Chapel Hill Kidney Tissue Layers • Renal Fascia (superficial) • Anchor kidney to surrounding structures and posterior abdominal wall • Adipose Capsule (intermediate) • Protection • Holds kidney in place • Renal Capsule (deep) • Protection from trauma and infection • Maintainance of shape • Continuous with ureter The University of North Carolina at Chapel Hill The University of North Carolina at Chapel Hill Kidney Tissue Layers The University of North Carolina at Chapel Hill The University of North Carolina at Chapel Hill Blood Supply of Kidneys • Renal artery • Delivers blood into kidney • Afferent Arteriole • Delivers blood into glomerulus • Efferent Arteriole • Delivers blood away from glomerulus • Peritubular capillaries • Surrounds renal tubule, to collect the filtered blood • Renal Vein • Delivers blood away from kidney The University of North Carolina at Chapel Hill The University of North Carolina at Chapel Hill The University of North Carolina at Chapel Hill The University of North Carolina at Chapel Hill Kidney Internal Anatomy • Two regions • Renal Cortex • Outer reddish covering • Extends from renal capsule to bases of the renal pyramids and into the spaces in between them • Renal Columns • Spaces between pyramids • Renal Medulla • Inner reddish brown area • Renal pyramids • 8­18 cone shaped structures • Bases of pyramids face cortex • Apex: = renal papillae • Points toward center of kidney (renal hilium) The University of North Carolina at Chapel Hill The University of North Carolina at Chapel Hill Kidney Internal Anatomy • Parenchyma = renal cortex + renal pyramids • Functional portion of kidney • Contains about 1 million nephrons • Nephron • Functional unit of the kidney • Urine is produced here and drained to papillary ducts The University of North Carolina at Chapel Hill The University of North Carolina at Chapel Hill Nephrons • Functional units of the kidneys • Consists of renal corpuscle and renal tubule • Functions: • Filtration • Wastes filtered from blood into nephron • Resorption • Useful materials returned to blood • Secretion • Wastes released from nephron into filtrate The University of North Carolina at Chapel Hill The University of North Carolina at Chapel Hill Renal corpuscle Renal Tubule Nephron Anatomy • Renal Corpuscle • Site of blood filtration (plasma is filtered) • Glomerulus • Capilary network • Bowman’s Capsule • Encapsulates glomerulus • Filtrate: blood that passed through the glomerular capillary to the space of Bowman's capsule The University of North Carolina at Chapel Hill The University of North Carolina at Chapel Hill Bowman’s capsule Glomerulus Nephron Anatomy • Renal Tubule • Passage of filtrate • Proximal Convoluted Tubule • Descending portion • Attached to glomerulus/bowman’s capsule • Located in renal cortex • Loop of Henle • Located in renal cortex & medula • Distal Convoluted Tubule • Ascending portion • Located in renal cortex The University of North Carolina at Chapel Hill The University of North Carolina at Chapel Hill Pathway of urine • • • • Renal Tubule Collecting duct Papillary duct Renal papilla • Apex of renal medulla • Minor calyx (calyces) – Small depressions at apex of pyramid (papillae) – 8­18 per kidney • Major calyx – 2­3 per kidney • Renal Pelvis • • Expanded upper end of the ureter Collection center for urine The University of North Carolina at Chapel Hill The University of North Carolina at Chapel Hill Physiology of urinary system • Filtration of blood • Re­absorption • Secretion The University of North Carolina at Chapel Hill The University of North Carolina at Chapel Hill Glomerular Filtration • Filtration of blood at the renal corpuscle • Glomerular Filtration Rate • Volume of fluid filtered per unit time • Males 125ml/min • Females 105ml/min 125ml/min x 60min x 24 hour = 180L/day = 47.6 Gallon!! The University of North Carolina at Chapel Hill The University of North Carolina at Chapel Hill Bowman’s capsule Renal Artery Glomerulus Renal Vein Re­absorption •Proximal convoluted tube •65% of the filtered water •Glucose, amino acids, lactic acids, vitamines etc. •Descending Loop of Henle •15% of the filtered water •Ascending Loop of Henle •Re­absorption of Na+, K+, Cl2­ •Distal convoluted tube •Re­absorption of Na+, K+, Cl2­ •Collected duct •Re­absorption of Na+, K+, Cl2­ The University of North Carolina at Chapel Hill The University of North Carolina at Chapel Hill Ureters • 2 ureters each ~10 inches in length • Communicating link b/w the renal pelvis and the urinary bladder • Transport urine from kidney to urinary bladder • Muscle contraction (walls), gravity & pressure The University of North Carolina at Chapel Hill The University of North Carolina at Chapel Hill Urinary Bladder • Hollow muscular organ • Size increases as it fills w/ urine • Rises into abdominal cavity when full • Capacity ~ 700 – 800 mL • Smaller in females due to uterus sitting superiorly • Located posterior to the pubic symphysis • Storage area for urine The University of North Carolina at Chapel Hill The University of North Carolina at Chapel Hill Urinary Bladder • Trigone • Triangular area on floor of bladder • Posterior: ureteral openings • Anterior: urethral opening The University of North Carolina at Chapel Hill The University of North Carolina at Chapel Hill The University of North Carolina at Chapel Hill The University of North Carolina at Chapel Hill Urinary Bladder • Valve mechanism • No actual valve b/w ureter and urinary bladder • As the urinary bladder swells, pressure is placed on ureter openings • Ureters are shut off, preventing backflow of urine • Potential role in kidney infection The University of North Carolina at Chapel Hill The University of North Carolina at Chapel Hill Urethra • Transports urine from the bladder to outside the body • External urethral orifice • Shorter in females than males • Results in higher rate of urinary tract infections in females The University of North Carolina at Chapel Hill The University of North Carolina at Chapel Hill The University of North Carolina at Chapel Hill The University of North Carolina at Chapel Hill Micturition (Urination) • Caused by voluntary and involuntary actions • Mictrition reflex • Urine level > 200 – 400 mL • Stretch receptors in urinary bladder wall activated • Conscious desire to urinate • Relaxation of the internal urehtral spincter & Contraction of detruser muscle The University of North Carolina at Chapel Hill The University of North Carolina at Chapel Hill Renal Calculi • Kidney stones • Crystallization of salts within filtrate • Excess calcium • Decreased water intake • Abnormal pH of filtrate • Over activity of the parathyroid glands • Parathyroid hormone = increases calcium content of blood ...
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This note was uploaded on 11/16/2011 for the course EXSS 175 taught by Professor Zinder during the Fall '08 term at UNC.

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