Urinary System Flashcards
What are the functions of the kidneys?
Filter blood and excrete toxic metabolic wastes
Regulate blood volume, pressure, and osmolarity
Regulate electrolytes and acid-base balance
Secrete erythropoietin, which stimulates the production of red blood cells
Help regulate calcium levels by participating in calcitriol synthesis
Clear hormones from blood
Detoxify free radicals
In starvation, they synthesize glucose from amino acids
____ is a by-product of protein metabolism
Urea
What is the step-by-step process of proteins to urea?
It goes from proteins to amino acids, where the NH2 gets removed, then ammonia is formed, to which the liver converts that to urea
____ is nucleic acid catabolism?
Uric acid
____ is the product of creatine phosphate catabolism
Creatinine
What is the normal concentration of blood urea supposed to be?
10 to 20 mg/dL
____ can be defined as separating wastes from body fluids and eliminating them
Excretion
What are the 4 systems that carry out excretion?
Respiratory, integumentary, digestive and urinary systems
What does the respiratory excrete?
CO_2, small amounts of other gases, and water
What does the integumentary excrete?
Water, inorganic salts, lactic acid, urea in sweat
What does the digestive system excrete?
Water, salts, CO_2, lipids, bile pigments, cholesterol, and other metabolic waste
What does the urinary system excrete?
Many metabolic wastes, toxins, drugs, hormones, salts, H^+, and water
What are the CT coverings/layers hat protect the kidney?
Renal fascia, adipose (perirenal) capsule, renal (fibrous) capsule
What layer binds kidney to abdominal wall?
Renal fascia
What layer cushions and supports kidney; holds it in place?
Adipose (Perirenal) Capsule
What layer surrounds kidney like cellophane wrap; protects from trauma and infection?
Renal (Fibrous) Capsule
What is the sectional anatomy of the kidney composed of?
Renal cortex, renal medulla, renal columns and lobes of kidney
____ is the path of blood through the kidney
Renal circulation
Explain the path of blood in the reanl artery.
Interlobular arteries to arcuate arteries to interlobar (cortical radiate) arteries to afferent arterioles to glomerulus to efferent arterioles to peritubular capillaries
How does blood exit the kidney?
It flows back through the interlobular, arcuate and interlobar veins and finally exits through the renal vein
Innervate kidneys and ureters
Enter each kidney at hilum
Follow tributaries of renal arteries to individual nephrons
These are common features of the ____ nerves
Renal
What does sympathetic innevation of the renal nerve supply do?
Adjusts rate of urine formation and stimulates the release of renin
What are nephrons?
Microscopic, tubular structures in cortex of each lobe of the kidney where urine production begins
How many nephrons does each kidney have?
1.2 million
What is the nephron composed of?
The renal corpsucle and tubule
What part of the nephron filters the blood plasma?
Renal corpsucle
What makes up the renal corpsucle?
Consists of the glomerulus (ball of capillaries) and a two-layered glomerular (bowmans) capsule that encloses glomerulus
What kind of epithelium makes up the outer layer of the glomerular capsule?
Simple squamous
What is the inner layer of the glomerular capsule composed of?
Podocytes that wrap around the capillaries of the glomerulus
What seperates the two layers of the glomerular capsule?
Capsular space
____ is a long, coiled tube that converts the filtrate into urine (PCT, Nephron Loop, DCT)
Renal tubule
What does the renal tubule do?
Processes filtrate into urine
The ____ leaves the glomerular capsule
Proximal Convoluted Tubule
What features does the PCT have?
Longest, most coiled simple cuboidal epithelium with microvilli for absorption
What is the shape of the nephron loop and the limbs?
U shaped, with ascending and descending limbs
The nephron loopis made of the thick segement which has ____ epithelium and the thin segment which has ____ epithelium
Simple cuboidal
Simple squamous
What is the thick segment of the nephron loop involved in?
the active transport of salts
The ____ segment is very water peremeable
thin
What kind of microvillli does the DCT have?
Cuboidal and minimal
What is the end of the nephron?
The DCT
The ____ receives fluid from the DCTs of several nephrons as it passes back into the medulla.
Collecting duct
What is the flow of fluid starting from the glomerular capsule and ending with the urethra?
glomerular capsule - PCT - nephron loop - DCT - collecting duct - renal papilla (papillary duct) - minor calyx - major calyx - renal pelvis - ureter - urinary bladder - urethra
What are the proportions of the juxtamedullary and cortical nephrons?
Cortical - 85%
Juxtamedullary - 15%
The ____ nephrons are very short loops while the ____ are very long loops
Cortical and juxtamedullary
What are the 3 basic processes of urine formation?
Glomerular Filtration
Tubular Reabsorption and Secretion
Water Conservation
In ____ a plasma like filtrate of blood is created
Glomerular filtration
In ____ useful solutes from the filtrate are removed and returned back into the blood
Tubular resorption
In ____ additional wastes from the blood and added to the filtrate
Tubular secretion
In ____ water is removed from the urine and returned to the blood. Waste is concentrated here
Water conservation
What does the kidney convert?
Blood plasma to urine
____ is the fluid in the capsular space?
Glomerular filrate
What is the difference between glomerular fltarte and blood plasma?
GF has almost no protein
____ is fluid from the proximal convoluted tubule through the distal convoluted tubule
Tubular fluid
What removes or adds substances from the tubular fluid?
Tubular cells
____ is fluid that enters the collecting duct
Urine
Fluid flows through renal tubules too rapidly for them to reabsorb the usual amount of water and solutes
Urine output rises
Chance of dehydration and electrolyte depletion
are all symptoms of too ____ GFR
High
What happens in GFR is too low?
Wastes are reabsorbed
Azotemia may occur
____ is controlled by adjusting glomerular blood pressure from moment to moment
GFR
What are the 3 main homoestatic mechanisms by which GFR control is achieved?
Renal autoregulation
Sympathetic control
Hormonal control
What are the hormones that help control blood pressure and GFR?
Renin, angiotensin and aldosterone
What do baroreceptors in the carotid and aorta do in response to a drop in blood pressure?
They stimulate the sympathetic nervous system
Sympathetic fibers trigger release of ________ by the _____
renin
kidneys
Renin converts ________ (a blood protein) into _______
angiotensinogen
Angiotensin I
In lungs and kidneys, angiotensin-converting enzyme (ACE) converts angiotensin I to ________
Angiotensin II
What does Angiotensin II do to BP?
Raises it
What does Angiotensin II stimulate?
the adrenal cortex
What does the adrenal cortex secrete?
Aldosterone
Aldosterone ____ blood pressure by ____ urine volume
Increases and decreases
The ____ reabsorbs about ________ of glomerular filtrate, removes some substances from blood, and secretes them into tubular fluid for disposal in urine
PCT and 65%
What is the 2 routes of reabsorption by the PCT?
Transcellular and Paracellular routes
What does the PCT reabsorb?
Na+ (creates osmotic and electrical gradient important for reabsorption of H2O and solutes),
Cl-
glucose
bicarbonate
K+
Mg
Water (the kidneys reduce about 180 liters of urine each day, so it is obvious that water reabsorption is a significant function)
nitrogenous wastes
What does the PCT secrete?
Hydrogen ions
ANP stand for ________ and PTH stands for ______
Atrial Natiuretic Peptide
Parathyroid Hormone
____ is secreted by the atrial myocardium of the heart in response to high blood pressure
ANP
What does ANP do?
Promotes sodium and water excretion, increases urine volume and decreases blood pressure and volume
What are the effects of PTH?
Increases calcium reabsorption in DCT and blood, increases phosphate excretion in PCT, decreases new bone formation
