Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
55 Cards in this Set
- Front
- Back
Urinary System |
- A major part of homeostasis is maintaining the composition, pH & volume of body fluids within normal limits - Removes metabolic wastes and substances present in excess, including foreign substances like drugs & their toxic metabolites - Consists of the following organs: kidneys, ureters, urinary bladder, urethra |
|
kidneys |
- Filter blood and form urine - Reddish brown, bean- shaped organ with a smooth surface - Tough, fibrous capsule |
|
Ureters |
- Transport urine from kidneys to urinary bladder |
|
Urinary bladder |
- Collects and stores urine |
|
Urethra |
- Conveys urine from urinary bladder to outside of body |
|
Location of the kidneys |
- Lie on either side of the vertebral column high in a depression on the posterior abdominal wall
- Retroperitoneal, behind the parietal peritoneum - Left is 1.5 to 2 cm higher than right - Surrounded by connective tissue (renal fascia) & masses of adipose tissue (renal fat) |
|
Renal Sinus |
- Hollow chamber in medial depression |
|
Hilum |
Entrance to renal sinus |
|
Renal pelvis |
- Funnel- shaped sac - Superior end of ureter - Collects all of the urine from the kidney, & then narrows as it leaves the kidney to become the ureter |
|
major calyces |
- Large tubes that merge to form renal pelvis |
|
minor calyces |
- Small tubes that merge to form major calyces |
|
Renal medulla |
- Inner region - Composed of renal pyramids |
|
Renal cortex |
- Outer region of kidney |
|
Renal columns |
- Extensions of cortex that dip into medulla |
|
Renal capsule |
- Fibrous capsule around kidney |
|
Nephrons |
- Functional units of kidney, each of which is a site of urine production
|
|
Renal Artery |
- Enters each kidney through the hilum, & continues to branch to the nephrons |
|
Nephrons |
- Each kidney contains about 1 million functional units |
|
Renal Corpuscle |
- Consists of a glomerulus and a glomerular capsule - Site of blood filtration in the kidney |
|
Glomerulus |
- Cluster of capillaries; Filters blood, (first step in urine formation) - Afferent arteriole -> Glomerulus -> Efferent arteriole |
|
Glomerular (Bowman's) Capsule |
- Receives filtrate from glomerulus |
|
Renal Tubule |
- Extends from glomerular capsule to collecting duct - Filtrate proceeds from glomerular capsule -> proximal convoluted tubule -> Nephron loop, composed of a descending and an ascending limb -> Distal convoluted tubule |
|
Cortical Nephrons |
- Sit high in cortex, with short nephron loops - Majority of nephrons |
|
Juxtamedullary nephrons |
- Sit low in cortex & have long nephron loops - Important in regulating water balance, & urine concentration - Small percentage of nephrons |
|
Juxtaglomerular Apparatus |
- A structure that regulates the secretion of renin - The top portion of the ascending limb of the nephron loop of each nephron passes between the afferent & efferent arterioles - The ascending limb comes in contact with the afferent arteriole, to form the juxtaglomerular appartus |
|
Macula densa |
- Tall, closely packed cells of the ascending limb |
|
Juxtaglomerular cells |
- Large vascular smooth muscle cells of the afferent arteriole |
|
Nephritis |
- Inflammation of the kidney |
|
Glomerulonephritis |
- Inflammation of the glomeruli - Acute or chronic |
|
Acute Glomerulonephritis (AGN) |
- Results of abnormal immue reaction, 1-3 weeks after infection by beta- hemolytic Streptococcus - Infection does not start in kidney - Antigen -antibody complexes form insoluble immune complexes, which lodge in the kidneys - Complexes deposit in and block glomeruli |
|
Chronic Glomerulonephritis |
- Progressive disease - More & more nephrons are damaged, until kidneys cannot function - Prolonged inflammation - Fibrous tissue replaces glomerular membranes, disabling nephrons |
|
Urine Formation |
- The main function of the nephrons & collecting ducts is to control the composition of body fluids & remove wastes from the blood, the product being urine - Contains: Wastes, excess water, & electrolytes - 3 processes: Glomerular filtration, tubular re-absorption, tubular secretion |
|
Glomerular filtration |
- First step of urine formation - Substances move from the blood in the glomerulus into the glomerular capsule - Water & small dissolved molecules & ions can be filtered - Large molecules, such as large proteins, remain in the blood because they're too large to pass through - Glomerular capillaries are many times more permeable than other capillaries |
|
Fenestrae |
- Tiny openings in walls |
|
Gomerular filtrate |
- Formed as substances filter from glomerulus into the glomerular capsule - Filtrate has about the same composition as tissue fluid |
|
Net Filtration pressure |
Force favoring filtration -- Forces opposing filtration |
|
Glomerular Filtration Rate (GFR) |
- Directly proportional to the net filtration pressure
- Average adult GFR = 125 mL/ min or 180 L/day - Blood plasma is filtered about 60x/day |
|
Autoregulation |
- GFR remains relatively constant through this process - Certain conditions override it, such as when GFR increases |
|
Renin- Angiotensin System |
- Responds to a decrease in BP - Secretion of ADH & aldosterone, it results in conservation of Na+ & H2O & an increase in BP. - Also keeps GFR constant |
|
Tubular Reabsorption |
- Movement of substances from the renal tubules into the interstitial fluid, where they then diffuse into the peritubular capillaries - 70% occurs in the proximal concoluted tubule, which is lined with microvilli - Different parts of the renal tubule reabsorb specific substances - Different substances are transported back into the internal environment by different methods of transport |
|
Tubular Secretion |
- Movement of wastes from peritubular capillaries into renal tubules - These substances are wastes, destined to be excreted in the urine - Active transport mechanisms function but they work in the opposite direction as tubular reabsorption - Secretion of subtances such as drugs & ions (k+) Secretion of H+ ions is important in regulating the pH of body fluids |
|
Active Transport |
- Movement of substances against their concentration gradients; limited transport capacity due to number of carrier proteins - Renal plasma threshold is reached when there is more transported substance in the plasma than the active transport mechanism can handle; excess spills into forming urine - Examples: Glucose, amino acids, creatine, lactic, citric, uric, and ascorbic acid, ion |
|
Osmosis |
- Water reabsorption |
|
Endocytosis |
- Small protein reabsorption |
|
Urea |
- A by- product of amino acid catabolism - The plasma concentration reflects the amount of protein in diet - Enters the renal tubules through glomerular filtration, & undergoes both tubular reabsorption & tubular secretion - about 80% is reabsorbed; 20% is excreted in the urine |
|
Uric Acid |
- A product of nucleic acid metabolism - It enters the renal tubules through glomerular filtration - Active transport completely reabsorbs the filtered uric acid - About 10% of uric acid enters urine through tubular secretions & is excreted |
|
Urine composition |
- About 95% water - Usually going to contain metabolic waste products: urea, uric acid, & creatine - Likely to contain trace amounts of amino acids & varying amounts of electrolytes |
|
Urine volume |
- 0.6 - 2.5 L/day - 50/60 mL of urine output/hour is normal - Volume varies with fluid intake & environmental factors |
|
Renal Clearance |
- Rate at which a chemical is removed from the plasma by the kidney - Indicates kidney efficiency, glomerular damage, progression of renal disease - Tests: Inulin clearance test, creatinine clearance test |
|
Ureters |
- Tubular organs, about 25 cm long - Each begins as renal pelvis in kidney - Join the urinary bladder in the pelvic cavity - Wall consists of 3 layers: Inner mucous coat (Transitional epithelium), middle muscular coat, outer fibrous coat |
|
Kidney Stones |
- Can be composed of uric acid, calcium oxalate, calcium phosphate, or magnesium phosphate - Form in collecting ducts or renal pelvis of kidney - Causes severe pain, nausea & vomiting, blood in urine - 60% of kidney stones pass on their own; others can be shattered with lithotripsy or removed surgically - Tendency to form these stones is inherited, specially calcium stones - Causes: Calcium supplements, Excess vitamin D, urinary tract blockage, UTI |
|
Urinary bladder |
- Hollow, distensible, muscular organ located within the pelvic cavity, posterior to the pubic symphysis & inferior to the parietal peritoneum - Storage organ for urine - Contacts the anterior walls of the uterus & vagina in female, lies against the rectum in male - Wall consists of 4 layers: Inner mucous coat, submucous coat, muscular coat, & outer serous coat |
|
Internal Urethral Sphincter |
- Surrounds the neck of the bladder |
|
Urethra |
- Tubular organ that conveys urine from the urinary bladder to the outside of the body
- Lined with a mucous membrane, & has a thick layer of longitudinal smooth muscle fibers - Has many mucous glands (urethral glands) - Female: 4 cm long, external urethral orifice is anterior to vaginal opening - Male: 19.5 cm long, dual function for both urination & reproduction |
|
Micturition or Urination reflex |
- Urine leaves the urinary bladder by this |