Urinary System Anatomy and Physiology PDF

Anatomy and Physiology URINARY SYSTEM URINARY SYSTEM - prevents infections in surrounding regions from...

Anatomy and Physiology URINARY SYSTEM URINARY SYSTEM - prevents infections in surrounding regions from spreading to the kidney INTERNAL ANATOMY OF THE KIDNEYS FUNCTIONS 1. produces erythropoietin and renin, which are vital molecules for regulating RBC production and BP 2. converts vitamin D in its active form 3. carries out gluconeogenesis during prolonged fasting URINE-FORMING KIDNEYS A. URETERS - paired tubes that transport urine from the kidneys to the urinary bladder B. URINARY BLADDER - temporary storage reservoir for urine C. URETHRA - tube that carries urine from the bladder to the body exterior EXTERNAL ANATOMY OF THE KIDNEYS A. RENAL HILUM - vertical cleft that leads into an internal space within the kidney - medial indentation where several structures enter or exit the kidney (ureters, renal blood, vessels, and nerves) B. RENAL SINUS - internal space within the kidney C. RIBCAGE DISTINCT REGIONS OF THE KIDNEY - its lower part protects the kidneys superficial to deep D. ADRENAL GLAND RENAL CORTEX - outermost region - sits atop of the kidney - light-colored and has a granular - functionally unrelated to the kidney appearance LAYERS OF SUPPORTIVE TISSUE RENAL MEDULLA - deeper in the cortex SURROUNDING EACH KIDNEY - reddish-brown in color superficial to deep RENAL (MEDULLARY) PYRAMID RENAL FASCIA - outermost capsule - triangular regions of tissue in and - anchors the kidney and exhibited by the renal medulla adrenal gland to its - its broad base faces toward the surrounding structures cortex apex, and the papilla points PERIRENAL FAT - fatty mass surrounding the internally CAPSULE kidney, providing a cushion - each constitutes to one of against blows approximately eight kidney lobes FIBROUS CAPSULE - transparent capsule - appear striated because they are formed almost entirely of parallel Anatomy and Physiology URINARY SYSTEM bundles of microscopic urine- for the small parts of that dip collecting tubules and capillaries into the outer medulla RENAL COLUMNS - mainly carries out excretory and - extensions of cortex-like material regulatory functions that separate the pyramids JUXTAMEDULLARY - originates close to the cortex RENAL PELVIS - flat medullary tube continuous NEPHRONS medulla junction with the hilum - makes up 15% of the nephrons BRANCHING EXTENSIONS - allows the kidney to produce - form two or three major calyces CALYCES diluted and concentrated urine - collect urine which drains from the papillae and empties into the renal RENAL CORPUSCLE pelvis - blood-filtering component of the nephron MAJOR CALYCES - each consists of a glomerulus and a glomerular - subdivides to form several minor capsule calyces - located in the renal cortex MINOR CALYCES - cup-shaped areas that enclose the RENAL TUBULE papillae - leaves the glomerular capsule as elaborately coiled URINE proximal convoluted tube - flows through the renal pelvis into - dropis into the hairpin loop called the nephron loop the ureter which moves it to the - winds an bladder for storage - each consists of a glomerulus and a glomerular capsule RENAL ARTERIES PROXIMAL CONVOLUTED TUBULE (PCT) - delivers one-fourth of the total cardiac output (about - with walls formed by cuboidal epithelial cells with 1200 ml) to the kidneys each minute under normal large mitochondria resting conditions - bears dense microvilli in the apical surfaces RIGHT RENAL ARTERY BRUSH BORDER - longer than to the left renal artery as it consists of the - increases surface area ang capacity of reabsorbing aorta that lies to the left of the midline water and solutes RENAL PLEXUS NEPHRON LOOP - variable network of autonomic fibers and ganglia - formerly called the “Loop of Henle” - provides nerve supply of the kidney and ureter - u-shaped loop containing descending and ascending - largely supplied by sympathetic fibers from the most limbs inferior thoracic and first lumbar splanchnic nerve A. PROXIMAL DESCENDING LIMB - courses along with the renal artery to rich the kidney - continuous with the proximal tubule which has similar SYMPATHETIC VASOMOTOR FIBERS cells - regulates renal blood flow by adjusting the diameter B. DESCENDING THIN LIMB of the renal arteriole - the rest of the descending limb that consists of single - influences the formation of urine by the nephron squamous epithelium cells NEPHRON C. ASCENDING THICK LIMB - structural and functional units of the kidney, with each - where the epithelium becomes cuboidal or even low having over a million columnar - carry out the processes that form urine D. ASCENDING THIN LIMB COMPONENTS OF A NEPHRON - thin segments around the bends of the nephron RENAL CORPUSCLE located in the renal cortex DISTAL CONVOLUTED TUBULE (DCT) RENAL TUBULE begins in the cortex, passes in the - cuboidal like PCT, but thinner and lacks microvilli medulla, and returns to the cortex COLLECTING DUCT A. PRINCIPAL CELLS CLASSES OF NEPHRON - maintains the body’s sodium and water balance CORTICAL NEPHRONS - located in the cortex - contains sparse and short microvilli - accounts for 85% of the B. INTERCALATED CELLS nephrons in the kidneys except - cuboidal cells with abundant microvilli Anatomy and Physiology URINARY SYSTEM - as two varieties (type A and type B) which maintains B. VISCERAL LAYER the acid balance of the body - clings to the glomerular capillaries JUXTAGLOMERULAR COMPLEX (JGC) - consists of podocytes - region where the most distal portion of the ascending PODOCYTES limb of the nephron loop lies against the afferent - highly modified branching epithelial cells and octopus- arteriole feeding the glomerulus like in shape - includes three populations of cells that help regulate FOOT PROCESSES the rate of filtrate formation and systemic blood - site of termination and where podocytes interdigitate pressure as they cling to the glomerulus’ basement membrane A. MACULA DENSA FILTRATION SLITS - “dense spot” - openings between the foot processes - group of tall, closely packed cells in the ascending - site of filtrate entry to the capsular space inside the limb of the nephron loop that lies adjacent to the glomerular capsule granular cells FILTRATION MEMBRANE - chemoreceptors that monitor the NaCl content of the - filter that lies between the blood in the glomerulus filtrate entering the DCT and the filtrate in the capsular space B. GRANULAR CELLS PERITUBULAR CAPILLARIES - “juxtaglomerular cells” - cling closely to adjacent renal tubules and empties - enlarged smooth muscles found in the arteriolar walls into nearby venules with prominent secretory granules containing renin - arise from high-resistance efferent arterioles making - acts as mechanoreceptors that sense blood pressure them experience low pressure in the afferent arteriole - readily absorbs solutes and water from tubule cells C. EXTRAGLOMERULAR MESANGIAL CELLS during the recovery of substances from the filtrate - lies between the arteriole and tubule cells which are VASA RECTA interconnected by a gap junction - long and straight vessels that form bundles which - pass regulatory signals between macula densa and extends into the medulla alongside the longest granular cells nephron loops NEPHRON CAPILLARY BEDS - thin-walled vessels that are crucial for producing - is closely associated with every nephron of the renal concentrated urine tubule GLOMERULUS - tuft of capillaries that maintains high pressure specialized for filtration - allows large amounts of solute-rich but virtually protein-free fluid to pass from the blood into the glomerular capsule - its capillaries’ endothelium is fenestrated (penetrated by many pores), making them porous FILTRATE - raw, plasma-derived fluid that the renal tubules process to form urine GLOMERULAR OR BOWMAN’S CAPSULE - cup-shaped hollow structure surrounding the glomerulus, continuous with the renal tubule - has an external parietal and visceral layer that clings to the glomerular capillaries LAYERS OF THE GLOMERULAR CAPSULE A. PARIETAL LAYER - stratified squamous epithelium - contributes to the capsule structure but plays no part in filtrate formation Anatomy and Physiology URINARY SYSTEM Anatomy and Physiology URINARY SYSTEM FLOW OF BLOOD SUPPLY IN THE KIDNEYS A. FENESTRATED ENDOTHELIUM OF THE 1. From the abdominal aorta, the renal arteries will exit GLOMERULAR CAPILLARIES at right angles. - has fenestrations (capillary pores) allow all blood 2. As each renal artery approaches a kidney, it divides components except blood cells to pass through into five segmental arteries. B. DECLINE IN OSMOLALITY 3. Within the renal sinus, each segmental artery - lies between the other two layers of the filtration branches further to form several interlobar arteries. membrane 4. The interlobar arteries branch into the arcuate arteries - forms a physical barrier that blocks all but the smallest that arch over the bases of the medullary pyramids at proteins, permitting other solutes to pass through the cortex-medulla junction. C. FOOT PROCESSES OF PODOCYTES OF THE GLOMERULAR CAPSULE 5. Small cortical radiate arteries (interlobular arteries) - visceral layer of glomerular capsule radiate outward from the arcuate arteries to supply - made of podocytes containing filtration slots between the cortical tissue (more than 90% of the blood their foot processes entering the kidney perfuses the renal cortex). SLIT DIAPHRAGM 6. Afferent arterioles branching from the cortical radiate - thin membranes extending across the filtration slit arteries begin a complex arrangement of microscopic - prevents most macromolecules from traveling farther blood vessels. the basement membrane 7. Blood leaving the renal cortex drains sequentially into REGULATION OF GLOMERULAR FILTRATION the cortical radiate, arcuate, interlobar, and finally - aids kidney to maintain extracellular balance renal veins. - increase in the GFR affects the urine output, reduces 8. Renal veins exit from the kidneys and empty into the blood volume and pressure vice versa. inferior vena cava. A. INTRINSIC CONTROLS 9. Veins will then trace the pathway of the arterial supply - aids in kidney autoregulation by altering its resistance in reverse. to blood flow despite changes in systemic arterial blood pressure B. EXTRINSIC CONTROLS - involves neural and hormonal mechanisms to regulate the GFR to maintain systemic blood pressure TUBULAR REABSORPTION - “reclaiming what the body needs to keep” - takes place in the renal tubules and collecting ducts - process of selectively moving substances from the filtrate back in the blood - reclaims filtered glucose, amino acids, water, salt, and other components URINE - produced from any component that was not reabsorbed during tubular reabsorption A. SODIUM REABSORPTION - transported across the basolateral and apical URINE PRODUCTION membranes GLOMERULAR FILTRATION - brings back sodium and supplies the energy needed to - “dumping into the waste container” - takes place in the renal corpuscle reabsorb almost everything else SODIUM IONS - produces a cell-free and protein-free filtrate - most abundant cation in the filtrate which uses - passive process in which hydrostatic pressure forces roughly 80% of energy to be reabsorbed fluids and solutes through a filtration membrane - occurs through the transcellular route and is primarily FILTRATION MEMBRANE active - lies between the blood and the interior of the B. NUTRIENTS, WATER, AND IONS REABSORPTION glomerular capsule - secondary active and passive tubular reabsorption of - porous membrane that allows the free passage of water and solutes water and solutes smaller than plasma proteins Anatomy and Physiology URINARY SYSTEM ROUTES OF REABSORBED SUBSTANCES A. TRANSCELLULAR ROUTE 1. Substances moves through the apical membrane. 2. Diffusion happens through the cytosol. 3. Components are transported across the basolateral membrane, involving the lateral intercellular spaces as the membrane transporters transports ions to these spaces. 4. It will then move through the interstitial fluid into the capillary. B. PARACELLULAR ROUTE 1. Substances moves through the leaky tight junctions, particularly in the PCT. 2. It will then move through the interstitial fluid into the capillary. REABSORPTION PROCESS A. ACTVE TUBULAR REABSORPTION - requires ATP URINE TRANSPORTATION, - occurs either directly (primary active transport) or STORAGE, AND ELIMINATION 1. Incoming urine distends the ureter and stimulates its indirectly (secondary active transport) in at least one muscularis to contract, propelling urine into the step B. PASSIVE TUBULAR REABSORPTION bladder. - involves diffusion, facilitated diffusion, and osmosis 2. The strength and frequency of the peristaltic waves - allows substances to move down their electrochemical are then adjusted to the rate of urine formation. gradients 3. Both sympathetic and parasympathetic fibers 1. Sodium is pumped into the interstitial space by the innervate each ureter in order to stimulate the sodium-potassium ATPase at the basolateral ureteral smooth muscle respond to stretch. membrane. 4. As urine accumulates, the bladder expands, becomes 2. Sodium then enters the apical membrane “downhill” pear shaped, and rises superiorly in the abdominal 3. Organic nutrient and certain ions are then reabsorbed cavity. by cotransport at the apical membrane. 5. The muscular wall stretches and thins making rugae 4. Water will be reabsorbed by osmosis through disappear, allowing the bladder to store more urine aquaporins increasing the concentration of solutes left without a significant rise in internal pressure. behind. These solutes can be reabsorbed as they move 6. At the bladder-urethra junction, the detrusor smooth down the gradients. muscle thickens to form the internal urethral 5. Lipid-soluble substances diffuse by the transcellular sphincter. route. 7. This involuntary sphincter controlled by the autonomic 6. Varius ions and urea diffuses by the paracellular route nervous system keeps the urethra closed when urine TUBULAR SECRETION is not being passed, preventing leaking between - “selectively adding to the waste container” voiding. - occurs along the length of the tubule and the 8. The external urethral sphincter on the other hand collecting duct serves as a voluntary constrictor of the urethra. - process of selectively moving substances from the 9. Urine is then drained from the bladder when of blood into the filtrate that have been reabsorbed by sphincters involuntarily and voluntarily open. passive processes, such as urea and uric acid MICTURITION REFLEX - urine is then excreted containing both filtered and - “urination” or “voiding” secreted substances, especially plasma proteins that - the act of emptying the urinary bladder aren’t generally filtered - restarts when more urine collects, but if delayed, it - rids the body of excess potassium and controls the pH dampens again level of blood A. CONTRACTING OF THE DETRUSOR - the pontine storage center inhibits urination by affecting nerve signals to the bladder activating stretch receptors in its walls Anatomy and Physiology URINARY SYSTEM - If we choose not to urinate, reflex contractions ease, - result of eating certain foods, presence of bile allowing urine to accumulate pigments, blood in the urine, or medications that alter B. OPENING OF INTERNAL URETHRAL SPHINCTER its color - impulses from the activated receptors via visceral C. CLOUDY afferent fibers to the sacral region of the spinal cord - may indicate the presence of Urinary Tract infection - visceral afferent impulses relayed by sets of (UTI) interneurons excites parasympathetic neurons and ODOR inhibit sympathetic neurons allowing the internal - ammonia and sulfur-containing molecules breakdown sphincter to open proteins and nitrogen-containing substances in the C. OPENING OF THE EXTERNAL URETHRAL SPHINCTER body which affects the smell of urine - the visceral afferent impulses also decrease the firing - may be influenced by certain medications, food, and rate of somatic efferent cells that keeps the external illnesses sphincter closed, relaxes and allows the urine to flow PH - we can voluntarily control the external sphincter, - normally around pH 6, which is slightly acidic delaying bladder emptying ACIDIC DIET - consumption of large amounts of protein and whole MICTURATION PROCESS BASED ON AGE INFANTS wheat products that causes urine to be more acidic - urination is controlled by the spinal ALKALINE DIET reflex that coordinates the whole - diet of large amount of vegetables, fruits, legumes, process basically a vegetarian diet which causes urine to be 1. When the bladder fills up, stretch alkaline receptors are activated which sends - may have side effects such as prolonged vomiting and signals to the spinal cord. bacterial infection of the urinary tract 2. Impulses from the activated receptors SPECIFIC GRAVITY travel via visceral afferent fibers to the - determined through the density of materials in sacral region of the spinal cord. dissolved urine which shows its solute concentration 3. Visceral afferent impulses relayed by - reflects the kidney’s ability to concentrate or dilute sets of interneurons, excite urine based on the body’s hydration status parasympathetic neurons and inhibit - a well-hydrated body allows the kidney to produce a sympathetic neurons. more diluted urine, lowering its specific gravity 4. Signals make the bladder contract which - ranges from 1.001 to 1.035 allows the sphincters to open, letting DEHYDRATION urine flow out. - leads to concentrated urine with a higher specific BETWEEN - brain’s descending circuits mature, gravity AGES 2-3 allowing conscious control over CHEMICAL COMPONENTS OF URINE urination A. UREA - bladder stretch signals are sent to the - largest component of urine by weight pons and higher brain centers, making - derived from the breakdown of amino acids us aware of bladder fullness B. URIC ACID PONTINE STORAGE URINATION - nitrogenous waste in the urine - inhibits micturition - end product of metabolism PONTINE MICTURITION CENTER C. CREATININE - promotes urination - metabolite of creatine phosphate - large amounts found in the skeletal muscle tissues PHYSICAL CHARACTERISTICS OF URINE where it stores energy to regenerate ATP COLOR AND TRANSPARENCY MAINTAINING WATER BALANCE IN THE BODY A. UROCHROME - overall body homeostasis is attained by maintaining - pigment is from the destruction of hemoglobin and proper concentration of water and various electrolytes solutes in the two main fluid compartments - the more concentrated the urine, the deeper the color - water intake and water output should be equal for the - freshly voided urine is clear and pale to deep yellow body to remain hydrated B. ABNORMAL COLOR - pink, brown, or smoky tinge Anatomy and Physiology URINARY SYSTEM OSMOLALITY - maintains contraction of muscles, neural function, and A. RISE IN OSMOLALITY general cellular activity - releases Antidiuretic Hormone (ADH) prompting D. FLUID BALANCE kidneys to conserve water and excrete concentrated - enough water regulates bodily fluid and composition, urine preserves blood pressure, avoids dehydration, and - stimulates thirst which prompts the body to drink guarantees appropriate hydration water E. REGULATION OF BLOOD PRESSURE B. DECLINE IN OSMOLALITY - kidneys release renin, a part of the renal-angiotensin- - inhibits thirst and Antidiuretic Hormone (ADH) release aldosterone system helping regulate blood pressure - prompts kidneys to excrete large volume s of dilute RELEVANCE OF THE URINARY SYSTEM urine TO NURSING PRACTICE WATER AND SODIUM IN OSMOLALITY A. ASSESMENT AND MONITORING - sodium is s a water magnet - urinary function is often assessed and monitored by - ADH and thirst mechanisms controlling osmolality nurses as part of a patient’s overall health assessment regulate water independently of sodium - monitoring urine output, color, clarity, and features - modifications and urine habits may serve as markers ROLE OF ANTIDIURETIC HORMONE for a number of medical conditions, including kidney - when extracellular fluid osmolality rises, blood levels disease, urinary tract infections, and dehydration of the antidiuretic hormone rises allowing the B. MANAGEMENT OF FLUID AND ELECTROLYTES collecting ducts to become more permeable to water, - renal function is directly related to fluid and which produces more concentrated urine in smaller electrolyte balance, which nurses are responsible for amounts monitoring and maintaining in patients - absence of the antidiuretic hormone allows dilute - nurses act to avoid dehydration or fluid overload, and filtrate to simply be allowed to pass the kidneys, monitoring urine output aids in assessing the state of forming diluted urine hydration HOW THE RAA SYSTEM MAINTAIN VASCULAR C. PREVENTION AND MANAGEMENT OF DISORDERS RESISTANCE AND BLOOD VOLUME - to avoid urinary tract infections, nurses instruct A. RENIN-ANGIOTENSIN MECHANISM patients on good hygiene practices - most important trigger of aldosterone release - when it comes to treating patients with renal - changes to the filtrates solute content results in low problems, such as acute kidney injury, chronic kidney blood pressure, stimulating the release of renin from disease, or kidney failure, nurses are essential the juxtaglomerular apparatus - this includes monitoring vital signs, controlling dialysis B. ALDOSTERONE treatments, giving medicine, and educating patients - regulates blood composition and blood volume by about food restrictions and lifestyle changes acting on the kidney tubules, promoting sodium D. ADMINISTRATITION OF MEDICINE reabsorption and water absorption - medication that may affect renal function is something - major factor in electrolyte concentration and osmotic that nurses need to be aware of possible toxicity or flow regulation adverse effects, since the kidneys are responsible for ANGIOTENSIN II excreting several medications - produced from the cascading reactions of renin - patients with reduced renal function may need to - increases vascular resistance via constriction and have their prescription dosage adjusted promotes aldosterone secretion on the adrenal cortex COMMON NURSING INTERVENTIONS IMPORTANCE OF THE URINARY SYSTEM IN HEALTHY KIDNEY MAINTENANCE A. MAINTAIN HOMEOSTASIS A. PATIENT EDUCATION - maintains homeostasis by controlling the composition - proper education on hydration, balanced low-sodium and volume of blood diet, and regular blood pressure and blood sugar level B. EXCRETION OF WASTE PRODUCTS monitoring can prevent and manage various - removes urea, creatinine, and excess salt from the conditions that affect kidney function, leading to blood by filtering and elimination better health outcomes for patients - avoids buildup of harmful chemicals B. PROMOTING HYDRATION C. MAINTENANCE OF ELECTROLYTE EQUILIBRIUM - helps maintain healthy kidneys by aiding in waste - kidney controlling the levels of electrolytes in the elimination through urine blood Anatomy and Physiology URINARY SYSTEM - adequate water intake optimizes blood flow to the 2. severe metabolic disturbances kidneys, aiding in waste filtration and electrolyte 3. cerebral edema and uncorrected cerebral edema balance maintenance TREATMENT C. DIETARY MANAGEMENT - administering intravenous hypertonic saline that - focusing on a balanced diet of fruits, vegetables, and reverses osmotic gradient, pulling water put of the cell proper protein portions to provide the kidneys with necessary nutrients - consuming foods that are rich in sodium, phosphorus, and potassium can put a strain on the kidneys, making it harder for them to function properly D. MONITORING AND ASSESMENT OF HEALTH - regular and consistent monitoring of vital signs such as blood pressure, heart rate, and temperature, coupled with frequent blood and urine tests, as well as keeping track of fluid intake, can be extremely beneficial in C. RENAL CALCULI (KIDNEY STONES) identifying any kidney abnormalities at an early stage - solutes from extremely concentrated urine forms - early detection of urinary issues can help healthcare crystals that precipitate in the renal pelvis professionals provide timely and effective treatment, - solid masses of crystals eventually moves down the thus improving the patient's overall health outcome ureters, blocking the flow of urine which leads to DISEASES OF THE URINARY SYSTEM severe pain A. RENAL PTOSIS (NEPHROPTOSIS) SIGNS AND SYMPTOMS - “wandering kidney” or “floating kidney” 1. groin pain - congenital disease 2. testicle (men) pain or labia (women) pain - descent of either kidney (5 cm) when someone with 3. blood in the urine the condition moves from a supine to an upright 4. anormal urine color position 5. fever SIGNS AND SYMPTOMS 6. chills 1. sharp pain radiating into the groin 2. proteinuria or excessive protein in urine 3. hematuria or blood in urine 4. high blood pressure 5. vomiting 6. nausea D. URINARY TRACT INFECTION - infection of the urinary tract caused by bacteria from the skin or rectum entering the urethra CYTITIS OR BLADDER INFECTION - most common type of UTI SIGNS AND SYMPTOMS 1. pain or burning sensation when urinating 2. frequent urination 3. pressure or cramping in the groin or lower abdomen 4. fever B. HYPOTONIC HYDRATION E. DIABETES INSIPIDUS - cellular overhydration caused by drinking - inability of kidneys to properly retain water due to extraordinary amounts water very quickly abnormalities in the release of ADH from the posterior - inhibition of ADH release reabsorbing less water and pituitary gland immediately flushing it out SIGNS AND SYMPTOMS SIGNS AND SYMPTOMS 1. severe dehydration 1. hyponatremia or low ECF sodium concentration 2. stimulated thirst response producing swelling in tissue cells due to osmosis 3. huge amounts of urine excreted per day (25L)