Urinary System Organs PDF

ANA ANA 204 Topic: URINARY SYSTEM ORGANS BY: BY : DR ANDRE  THE URINARY SYSTEN Thousands of metab0lic processes in myriad 60dy cells pr0duce hundreds Of waste pr0du4s. The urinary system removes them by filtering and cleansing th...

ANA ANA 204 Topic: URINARY SYSTEM ORGANS BY: BY : DR ANDRE  THE URINARY SYSTEN Thousands of metab0lic processes in myriad 60dy cells pr0duce hundreds Of waste pr0du4s. The urinary system removes them by filtering and cleansing the 6I00d as it passes thr0ugh the kidneys. Afi0ther vital functi0n is the regulatÏ0fi Of the v0lume, acidity, salinity, c0ncentration, and chemical comp0SÏtÏ0h Of bI00b,I MgÈ, ühb Other 60dy fuids. Under h0rm0nal contr0l, the kidneys c0ntinuall/ M0hit0r what they release int0 the urine IO mdintaina healthy chemical balance. 2 The urinary system is c0mposed ofa pair of URINARY SYSTEM kidneys,a pair of ureters,a bladder, and a urethra. These components together carry out the urinary system's function of regulating the V0lume and comp0Sition of body fluids, removing waste products from the blood, and expelling the waste and exCe5S Water fr0m the b0dy in the form 0f urine. The tno kidneys are reddish organs resembling beans in shape that are situated on either side of the abd0ITIen just above the waist and t0wards the back of the dody. ure|ef The kidneys contain micr0sc0pic filtering units that remove waste, unwanted minerals, and excess water from the blo0d as urine. b adder Each kidney is connected to the bladder dya long tube calleda ureter, which transpols urine — vrettra away. 3  4 0 0 ¿ a0 g u.-*"0 ğ -r g u w 0.E gš “ ł 0 0 E g p 17/07/2014 4 Š # u0 17/07/2014 5  Internal Anatomy oftheKidney Certléol iadlcte Arcciate veTn Renel.column Areuata artery tnterJobm'vain Major ozdyñ ritnor calyz Ronisl Mem Renal pelv'fe.Mzgor celyx urstar G0P»rghI@ Zo0B PBdfB‹x1 €@JCbtorI; 1ñ'., pLozShblg as:Bert zziTtF› cUlTllTllñps. '. '. ”'-” Copyñght 0 2O0b Pearson Educalim. Inc., publishlng as Benjamin Cummings 17/07/2014 6  KIDNEY Kidney cross section This cutaway shows the kidney's main layers, the kidney’s the and the the cortex and the medulla, which form segments known as asrenal renal pyramids. The and vein circulate huge The renal artery and amounts ofofblood blood —about2 1/2 pints/min at –about 2 1/2 rest, which is up up to to one-quarter of the heart’s heart's total output. Blood enters the kidneys through renal arteries. These aleries branCh into tiny Cd illaries that interaCt With urinary struCtures inside the kidneys (namely the nephrons). Here the blood is filtered. Waste is removed and vital subStanCes are reabsorbed back into the bloodstream. The filtered blood leaves through the renal veins. All the blood in the body moves in and out of the kidneys hundreds oftimes each day—that's about 200 quarts of liquid to be filtered every 24 hours. Each kidney contains over1 million tiny structures called nephrons. The nephrons are located partly in the cortex and pa1Iy inside the renal pyramids, where the nephron tubules make up most of the pyramid mass. Nephrons perform the primary function of the kidneys: regulating the concentration of water and other substances in the body. They filter the blOod, reabsOrb what the body needs, and excrete the rest as urine. The kidneys filter unwanted substances from I\9 blO0J anJ pr0Juce urine ts excrete then. There are3 main ste§S Of urine fOrrratÏOF: Glomerular filtrati0n, ReabsOrptiOI1 Secretioh. Thèse promesses ensure that Only raste ana excess water are remoVeä from t\9 b»Jy. Each nephron hasa glomerulus, the site of blOOd filtration. The glomerulus isa network Of capillaries surrounded bya cuplike structure, the glomerular capsule (Or BOrlzlans capsule). As blO0d flO¥/s thr0ugh the glomerulus, blOOd pressure pushes rater and s0lutes from the capillaries into the capsule I\rOugLa filtrati0n membrane. This glomerular filtratioh degins the urine formation process. The nephrons Of the kidneys process blOOd and create urine thrOughd gFOCQSS Of filtration, reabs0rpti0h, ahd 5ecreti0h. Urine is about 950/owater and 5% waste products. NitrOgenous wastes excreted in urine include urea, creatinine, ammonia, and uric acid. I0ns Such d5 S0giUM, g0td5SiUITI, hydr0gen, and calcium are al50 excreted. Urine produced in the kidneys travels down the ureters into the urinary bladder. The bladder expands like an 9ldStiC Sae to hold more urine. As it reaches capacity, the process of micturition, or urination, begins. Involuntary muscle movements send signals to the nervous system, putting the decision IO urinate under cOnsci0uS COntrOl. The internal urethral sphincter and the external urethral sphincter both provide muscle control for the flow of urine. The internal sphincter is involuntary. It surrounds the opening of the bladder to the urethra and relaxes to allow urine to paS5. The external sphincter is voluntary. It surrounds the urethra outside the bladder and must de relaxed for urination to occur.  URINARY BLADDER Smooth muscle stretch initiates the micturition the micturition by activating stretch receptors in the reflex by the bladder wall. This autonomic reflex causes the detrusor muscle to contract and and the the internal urethral sphincter muscle to relax, allowing urine to flow into the the urethra. The The stretch receptors also send sendaa message tothe to the thalamus and and the cerebral cortex, giving voluntary control over the external urethral sphincter. sphincter. We We usually gain this control of urination between the the ages of22 and and 3, as as our our brains develop.