Bio202 Urinary System Notes PDF

ARIZONA STATE UNIVERSITY Urinary System College of Integrative Sciences & Arts Bio 202 A natomy & Physiology II Tonya A. Penkrot, Ph.D.  Function of Kidneys  Kidneys, a major excretory organ, mai...

ARIZONA STATE UNIVERSITY Urinary System College of Integrative Sciences & Arts Bio 202 A natomy & Physiology II Tonya A. Penkrot, Ph.D.  Function of Kidneys  Kidneys, a major excretory organ, maintain the body’s internal environment by: Regulating total water volume and total solute concentration in water Regulating ion concentrations in extracellular fluid (ECF) Ensuring long-term acid-base balance Excreting metabolic wastes, toxins, drugs Producing renin (regulates blood pressure) and erythropoietin (regulates RBC production) Activating vitamin D Carrying out gluconeogenesis, if needed Bio 202 A&P ASU DPC T. Penkrot © 2016 Pea rs on Education, Inc. Figure 25.1 The urinary system. Hepatic veins (cut) Esophagus (cut) Inferior vena cava Renal artery Adrenal gland Renal hilum Aorta Renal vein Kidney Iliac crest Ureter Rectum (cut) Uterus (part of female reproductive system) Urinary bladder Urethra Bio 202 A&P ASU DPC T. Penkrot © 2016 Pea rs on Education, Inc. Figure 25.3b Position of the kidneys against the posterior body wall. 12th rib Bio 202 A&P ASU DPC T. Penkrot © 2016 Pea rs on Education, Inc. Figure 25.3a Position of the kidneys against the posterior body wall. Anterior Inferior vena cava Aorta Peritoneum Peritoneal cavity (organs removed) Supportive Renal tissue layers vein Renal fascia anterior Renal posterior artery Perirenal fat capsule Fibrous Body of capsule vertebra L2 Body wall Posterior Bio 202 A&P ASU DPC T. Penkrot © 2016 Pea rs on Education, Inc. Figure 25.4 Internal anatomy of the kidney. Renal hilum Renal cortex Renal medulla Major calyx Papilla of pyramid Renal pelvis Minor calyx Ureter Renal pyramid in renal medulla Renal column Fibrous capsule Photograph of right kidney, frontal section Diagrammatic view Bio 202 A&P ASU DPC T. Penkrot © 2016 Pea rs on Education, Inc.  Blood and Nerve Supply  Blood: kidneys cleanse blood and adjust its composition, so it has a rich blood supply Renal arteries deliver about one-fourth (1200 ml) of cardiac output to kidneys each minute Arterial flow: renal  segmental  interlobar  arcuate  cortical radiate (interlobular) Venous flow: cortical radiate  arcuate  interlobar  renal veins ― No segmental veins  Nerve supply: via sympathetic fibers from renal plexus Bio 202 A&P ASU DPC T. Penkrot © 2016 Pea rs on Education, Inc. Figure 25.5a Blood vessels of the kidney. Cortical radiate vein Cortical radiate artery Arcuate vein Arcuate artery Interlobar vein Interlobar artery Segmental arteries Renal vein Renal artery Renal pelvis Ureter Renal medulla Renal cortex Frontal section illustrating major blood vessels Bio 202 A&P ASU DPC T. Penkrot © 2016 Pea rs on Education, Inc. Figure 25.5b Blood vesselsAorta of the kidney. Inferior vena cava Renal artery Renal vein Segmental artery Interlobar vein Interlobar artery Arcuate vein Arcuate artery Cortical radiate vein Peritubular Cortical radiate artery capillaries or vasa recta Afferent arteriole Efferent arteriole Glomerulus (capillaries) Nephron-associated blood vessels (see Figure 25.8) Bio 202 A&P ASU DPC T. Penkrot Path of blood flow through renal blood vessels © 2016 Pea rs on Education, Inc.  25.2 Nephrons  Nephrons are the structural and functional units that form urine  > 1 million per kidney  Two main parts Renal corpuscle Renal tubule Bio 202 A&P ASU DPC T. Penkrot © 2016 Pea rs on Education, Inc. Figure 25.6 Location and structure of nephrons. Renal cortex Renal medulla Renal pelvis Gl omerular ca psule: parietal layer Ureter Basement membrane Podocyte Kidney Fenestrated Renal corpuscle endothelium Glomerular capsule of the glomerulus Glomerulus Gl omerular ca psule: vi sceral l ayer Di s tal convol uted Apical microvilli tubul e Mitochondria Highly Proxi ma l infolded convol uted basolateral tubul e membrane Proxi ma l convoluted tubule cells Cortex Apical side Medulla Basolateral side Thick segment Di s tal convoluted tubule cells Thin segment Nephron l oop Descending limb Ascending limb Col l ecting Nephron l oop (thin-segment) cells duct Principal cell Intercalated cell Col l ecting duct cells Bio 202 A&P ASU DPC T. Penkrot © 2016 Pea rs on Education, Inc. Figure 25.12a The filtration membrane. Glomerular capsular space Efferent arteriole Afferent arteriole Proximal convoluted Glomerular capillary tubule covered by podocytes Parietal layer that form the visceral layer of glomerular of glomerular capsule capsule Renal corpuscle Bio 202 A&P ASU DPC T. Penkrot © 2016 Pea rs on Education, Inc. Figure 25.12b The filtration membrane. Cytoplasmic extensions of podocytes Filtration slits Podocyte cell body Fenestrations (pores) Glomerular capillary endothelium (podocyte covering and basement Foot processes membrane removed) of podocyte Glomerular capillary surrounded by podocytes Bio 202 A&P ASU DPC T. Penkrot © 2016 Pea rs on Education, Inc. Figure 25.12c The filtration membrane. Filtration slits Podocyte cell body Foot processes Bio 202 A&P ASU DPCFiltration T. Penkrot slits between the podocyte foot processes © 2016 Pea rs on Education, Inc. Figure 25.7 Renal cortical tissue. Renal corpuscle Proximal Squamous epithelium convoluted of parietal layer of tubule (fuzzy glomerular capsule lumen due to long microvilli) Glomerular capsular space Distal convoluted Glomerulus tubule (clear lumen) Bio 202 A&P ASU DPC T. Penkrot © 2016 Pea rs on Education, Inc. Figure 25.8 Cortical and juxtamedullary nephrons, and their blood vessels. Cortical nephron Juxtamedullary nephron Short nephron loop Long nephron loop Glomerulus further from Glomerulus closer to the the cortex-medulla junction cortex-medulla junction Efferent arteriole Gl omerulus Efferent Cortical radiate vein Efferent arteriole supplies supplies peritubular (capillaries) a rteri ole Cortical radiate artery vasa recta capillaries Renal corpuscle Glomerular Afferent arteriole capsule Collecting duct Proximal Distal convoluted tubule convoluted Afferent arteriole tubule Efferent a rteri ole Peri tubular ca pi llaries Ascending limb of nephron loop Cortex-medulla junction Arcuate vein Kidney Va s a recta Arcuate artery Nephron loop Descending limb of nephron loop Bio 202 A&P ASU DPC T. Penkrot © 2016 Pea rs on Education, Inc. Figure 25.9 Blood vessels of the renal cortex. Peritubular capillary bed Afferent arteriole Glomerulus Efferent arteriole Bio 202 A&P ASU DPC T. Penkrot © 2016 Pea rs on Education, Inc.  Juxtaglomerular Complex (JGC) (cont.)  Each nephron has one juxtaglomerular complex (JGC): 1. Macula densa ― Contain chemoreceptors that sense NaCl content of filtrate 2. Granular cells (juxtaglomerular, or JG cells) ― Act as mechanoreceptors to sense blood pressure in afferent arteriole ― Contain secretory granules that contain enzyme renin 3. Extraglomerular mesangial cells May pass signals between macula densa and granular cells Bio 202 A&P ASU DPC T. Penkrot © 2016 Pea rs on Education, Inc. Figure 25.10 Juxtaglomerular complex (JGC) of a nephron. Glomerular capsule Efferent arteriole Glomerulus Parietal layer Foot processes of glomerular of podocytes Podocyte cell body capsule (visceral layer) Capsular Red blood cell space Afferent Efferent arteriole Proximal arteriole tubule cell Juxtaglomerular Complex: Macula densa cells of the ascending limb of nephron loop Extraglomerular Lumens of mesangial cells glomerular Granular cells capillaries Endothelial cell Afferent arteriole of glomerular capillary Glomerular mesangial cells Juxtaglomerular complex Renal corpuscle Bio 202 A&P ASU DPC T. Penkrot © 2016 Pea rs on Education, Inc.  25.3 Physiology of Kidney  180 L of fluid processed daily, but only 1.5 L of urine is formed  Kidneys filter body’s entire plasma volume 60 times each day  Consume 20–25% of oxygen used by body at rest  Filtrate (produced by glomerular filtration) is basically blood plasma minus proteins  Urine is produced from filtrate Urine ― 125 ml/min, substance was secreted (most drug metabolites) Bio 202 A&P ASU DPC T. Penkrot © 2016 Pea rs on Education, Inc.  Urine (cont.) Other normal solutes found in urine ― Na+, K+, PO43–, and SO42–, Ca2+, Mg2+ and HCO3– Abnormally high concentrations of any constituent, or abnormal components such as blood proteins, WBCs, and bile pigments, may indicate pathology Bio 202 A&P ASU DPC T. Penkrot © 2016 Pea rs on Education, Inc.  Urine (cont.)  Physical characteristics Color and transparency ― Clear  Cloudy may indicate urinary tract infection ― Pale to deep yellow from urochrome  Pigment from hemoglobin breakdown  Yellow color deepens with increased concentration ― Abnormal color (pink, brown, smoky)  Can be caused by certain foods, bile pigments, blood, Bio 202 A&P ASU DPC T. Penkrot drugs © 2016 Pea rs on Education, Inc.  Urine (cont.) Odor ― Slightly aromatic when fresh ― Develops ammonia odor upon standing as bacteria metabolize urea ― May be altered by some drugs or vegetables (ex.= asparagus) ― Disease may alter smell  Patients with diabetes may have acetone smell to urine Bio 202 A&P ASU DPC T. Penkrot © 2016 Pea rs on Education, Inc.  Urine (cont.) pH ― Urine is slightly acidic (~pH 6, with range of 4.5 to 8.0) ― Acidic diet (protein, whole wheat) can cause drop in pH ― Alkaline diet (vegetarian), prolonged vomiting, or urinary tract infections can cause an increase in pH Specific gravity ― Ratio of mass of substance to mass of equal volume of water (specific gravity of water = 1) ― Ranges from 1.001 to 1.035 because urine is made up of water and solutes Bio 202 A&P ASU DPC T. Penkrot © 2016 Pea rs on Education, Inc. Figure 25.20 Cross-sectional view of the ureter wall (10). Lumen Mucosa Transitional epithelium Lamina propria Muscularis Longitudinal layer Circular layer Adventitia Bio 202 A&P ASU DPC T. Penkrot © 2016 Pea rs on Education, Inc. Figure 25.21a Structure of the urinary bladder and male urethra. Peritoneum Ureter Rugae Detrusor Adventitia Ureteric orifices Trigone of bladder Bladder neck Internal urethral sphincter Prostate Prostatic urethra Intermediate part of the urethra External urethral sphincter Urogenital diaphragm Spongy urethra Erectile tissue of penis External urethral orifice Male. The long male urethra has three regions: prostatic, Bio 202 A&P ASU DPC T. Penkrot intermediate, and spongy. © 2016 Pea rs on Education, Inc. Figure 25.21b Structure of the urinary bladder and female urethra. Peritoneum Ureter Rugae Detrusor Ureteric orifices Bladder neck Internal urethral sphincter Trigone External urethral sphincter Urogenital diaphragm Urethra External urethral orifice Bio 202 A&P ASU DPC T. Penkrot Female. © 2016 Pea rs on Education, Inc.  Urinary Bladder (cont.)  Urine storage capacity Collapses when empty Rugae appear Expands and rises superiorly during filling without significant rise in internal pressure Moderately full bladder is ~12 cm long (5 in.) and can hold ~ 500 ml (1 pint) ― Can hold twice that amount if necessary but can burst if overdistended Bio 202 A&P ASU DPC T. Penkrot © 2016 Pea rs on Education, Inc.  Urethra (cont.)  Sphincters Internal urethral sphincter ― Involuntary (smooth muscle) at bladder-urethra junction ― Contracts to open External urethral sphincter ― Voluntary (skeletal) muscle surrounding urethra as it passes through pelvic floor  Female urethra (3–4 cm): tightly bound to anterior vaginal wall External urethral orifice: anterior to vaginal opening; posterior to clitoris Bio 202 A&P ASU DPC T. Penkrot © 2016 Pea rs on Education, Inc.  Urethra (cont.)  Male urethra carries semen and urine Three named regions ― Prostatic urethra (2.5 cm): within prostate ― Intermediate part of the urethra (membranous urethra) (2 cm): passes through urogenital diaphragm from prostate to beginning of penis ― Spongy urethra (15 cm): passes through penis; opens via external urethral orifice Bio 202 A&P ASU DPC T. Penkrot © 2016 Pea rs on Education, Inc. Figure 25.23 Control of micturition. Brain Higher brain Urinary bladder centers fills, stretching bladder wall Allow or inhibit micturition as appropriate Afferent impulses Pontine micturition Pontine storage from stretch center center receptors Simple Promotes micturition Inhibits micturition spinal by acting on all three by acting on all three spinal efferents spinal efferents reflex Spinal Spinal cord cord Parasympathetic Sympathetic Somatic motor Parasympathetic activity activity activity nerve activity Sympathetic activity Somatic motor nerve activity Detrusor contracts; External urethral internal urethral sphincter opens sphincter opens Inhibits Micturition Bio 202 A&P ASU DPC T. Penkrot © 2016 Pea rs on Education, Inc.