Renal System Flashcards
Learn the Urinary System
There are 5 Major functions of the Urinary System, Name them
- Regulation of water, inorganic ion balance, and acid-base balance
- Removal of metabolic waste from the blood (excreted through urine)
- Removal of foreign chemicals in the blood (excreted through urine)
- Gluconeogenesis (formation of glucose)
- Production of hormones
What hormones are produced in the urinary system? What are their functions? (3 total hormones)
- Erythropoietin- controls erythrocyte production
- Renin- enzyme controls the formation of angiotensin, influences blood pressure and sodium balance
- 1,25-dihydroxyvitamin D, influences calcium balance
Main components of the Urinary System
- 2 Kidneys
- 2 Ureters
- Urinary Bladder
- Urethra
How do the kidneys function?
they produce urine (fluid made of water, ions, soluble compounds)
How does the Urethra Function?
During micturition (urination), it conducts urine out of the body
Gross Anatomy of the kidneys (Location)
- located in the retroperitoneal space (posterior to the peritoneum)
- extend from T12 to L3
- protected by the floating ribs
- right kidney is crowded by liver (lower than left)
Give an overview of the surface of the kidneys
- convex lateral surface
- concave medial surface
- renal hilum leads to internal space (leads straight into the concave area)
Why is the renal Hilum important for the kidneys?
- ureters, renal blood vessels, lymphatics, and nerves enter and exit at the hilum
What are the four main features of the internal area of the kidney?
- Renal cortex, renal medulla, renal columns, and major and minor calyces
Renal Cortex (internal kidney)
outer regions (granular, reddish brown)
Renal Medulla (internal kidney)
inner regions composed of renal pyramids with striped appearance
Renal Columns (internal kidney)
separate renal pyramids
major and minor calyces (internal kidney)
collect urine
Give an overview of the structure and function of the ureters
- continuation of the renal pelvis
- carries urine out of the kidneys and to the bladder
- capable of peristalsis (rhythmic contractions of smooth muscle to propel urine to the bladder)
- bladder filling compresses the distal end of the ureter, preventing backflow
Microscopically, the ureters has 3 layers. What are they? (from deepest to superficial)
Deepest: Mucosa
Middle: Muscularis
Superficial: adventitia
What is the mucosa of the ureters? (microscopic)
- transitional epithelium
- readily stretches to accommodate distension from urine filling
What is the muscularis of the ureters? (microscopic)
- senses distention with urine filling and triggers reflexive peristalsis
What is the adventitia of the ureters? (microscopic)
- fibrous connective tissue
- anchors the ureter in place
Renal Calculi
kidney stones in renal pelvis (crystalized calcium, magnesium, or uric acid salts)
- large stones can block the ureter causing pressure and pain
Why are kidney stones caused? What is the treatment?
- genetics, diet, bacterial infection, increased blood calcium levels, or high pH of urine
- treatment- shock wave lithotripsy- non invasive procedure sending shock waves to shatter calculi
Give a brief overview of the Urinary Bladder Anatomy.
- a muscular sac for temporary storage of urine
- located on the pelvic floor posterior to pubic symphysis
- Males: superior to prostate
- Females: anterior to vagina and uterus
5 Common features of the bladder in both men and women
- trigone: triangular area at the bottom of the bladder marked by the openings for the paired ureters and urethra
- Inner mucosa of bladder: transitional epithelium that fold into rugae
- middle layer is the detrusor muscle: contains muscle that contracts to drive urination
- thick muscle near the opening leading to the urethra forms the internal urethral sphincter
- urethra passes through a ring of skeletal muscle on its way out the external urethral sphincter
Give a brief overview of the structure of the urinary system in females
- urethra is only 3-5 cm in length; functions only in transport of urine
Give a brief overview of the structure of the urinary system in males
- urethra is longer (20 cm); functions in transport of both urine and semen
What do the kidneys do to the blood?
they cleanse the blood and adjust the composition, so it has a rich blood supply
What arteries deliver about 1/4 of cardiac output to kidneys each minute?
renal arteries
What are the kindye’s filtration rates?
- females: 115 ml/min
- males: 125 ml/min
about 45 gallons a day
study the overall structure of kidney vasculature
What are nephrons?
the structural and functional units that form urine
What are the two main parts of nephrons?
renal corpuscle
renal tubule
Give a brief overview of the overall structure of kidney nephrons
- afferent arterioles drain into the glomerulus (leaky capillaries)
- filtration occurs when fluid/ solutes are forced from the blood into the glomerular capillaries and into the surrounding bowman’s capsule
- blood is drained from the glomerulus by efferent arterioles
What are cortical Nephrons?
- short nephron loop
- glomerulus further from the cortex-medulla junction
- efferent arteriole supplies peritubular capillaries
what are juxtamedullary nephron?
- long nephron loop
- glomerulus closer to the cortex-medulla junction
- efferent arteriole supplies vasa recta
Give the order of the flow of fluid through the nephron’s tubules.
- Proximal convoluted tubule (PCT)
- Descending Tube (DT)
- Loop of Henle (LH)
- Ascending Tube (AT)
- Distal convoluted Tubule (DCT)
Proximal convoluted tubule (PCT) (give location and types of cells)
- located within the cortex
- simple epithelium with microvilli
Descending Tube (location, segments)
- descends into the medulla
- alternates between thick and thin segments
Loop of Henle LH (connector)
- connects ascending and descending tubes
Ascending Tube (segments)
- alternates between thick and thin segments
Distal convoluted Tubule (cell type)
simple cuboidal epithelium without microvilli
Now give the flow of Fluid AFTER FILTRATION through the nephron
- filtrate from nephrons
- collecting duct (CD)
- To Renal Pelvis
Study the strucutre of nephrons slide !
What is the body water content in males?
60% water
What is the body water content of infants?
73% or more water (low body fat, low bone mass)
What is the body water content in females?
55% water (higher fat, lower muscle mass)
- adipose tissue is least hydrated, (10% water), muscle contains (75% water).
What are the two main fluid compartments?
Intracellular fluid compartment (ICF), and Extracellular fluid compartment (ECF)
Intracellular Fluid (ICF)
fluid inside cells (2/3 of total body fluid)
Extracellular Fluid
fluid in two main ECF compartments outside cell (1/3 of total body fluid)
- plasma (20%)
- Interstitial fluid (IF)- (80%) in spaces between cells
Water is the ________ solvent
universal
What are solutes?
substances dissolved in water
How are solutes classified?
electrolytes and non electrolytes
Nonelectrolytes
- most are organic molecules
- do not dissolve in water
- glucose, lipids, creatine, and urea
Electrolytes
- dissolve into ions in water (inorganic salts, all acids and bases)- ions conduct electrical current
- greater osmotic power than nonelectrolytes
How are fluid pools interconnected?
- fluid moves between pools in response to changes in pressure and osmotic gradients via aquaporin channels
- change in osmolarity in any pools mean changes in all pools
How does fluid move among compartments?
- osmotic and hydrostatic pressures regulate fluids
- water moves freely
- all body fluid osmolarity is almost always equal
If there is a higher extracellular fluid osmolality, where does water move?
leaves the cell
if there is a lower extracellular fluid osmolality, where does water move?
water enters the cell
Exchanges between plasma and interstitial fluid occur across _________ _______
capillary walls
When fluid leaks from the arterial end of the capillary, where is it reabsorbed?
the venous end
___________ picks up remaining fluid and returns it to the blood
lymphatics
Exchanges between interstitial fluid and intracellular fluid occur across the ______ ____________
cell membrane
What happens when solutes are exchanged across the interstitial fluid and intracellular fluid ?
- two way osmotic flow of water
- ions move selectively into or out of the cell
- nutrients, wastes, and gases have unidirectional flow
In order to maintain homeostasis, what must be true of water balance?
water intake must equal water output
If there is a rise in osmolarity, what happens?
- thirst is stimulated
- causes ADH release from posterior pituitary
what happens if there is a decrease in osmolarity?
- ADH release is inhibited
What is the driivng mechanism for water intake?
the thirst mechanism
- governed by the hypothalamic thirst center
- also activated by dry mouth, decreased blood volume or pressure, and Angiotensin II
How does the hypothalamic thirst center control regulation of water intake?
- hypothalamic osmoreceptors detect extracellular osmolarity and activate the thirst center
- drinking of water inhibits the thirst center
What are obligatory water losses?
- water loss from lungs, skin, feces, from urine to excrete wastes
- why we cannot live without water very long
What causes Dehydration?
- extracellular fluid water loss due to hemorrhage, severe burns, prolonged vomiting, diarrhea, profuse sweating, water deprivation, diuretic abuse, endocrine disturbances
What are the symptoms of dehydration?
- “cottony” oral mucosa, thirst, dry flushed skin, headaches
- ECF osmotic pressure rises, cells lose H2O to ECF by osmosis, cells shrink
What may happen with dehydration if left untreated?
- mental confusion, hypovolemic shock, and seizures
When does Hypotonic hydration occur?
- also known as water intoxication
- renal insufficiency or rapid excess of water ingestion
What happens during hypotonic hydration?
- ECF osmolality decreases
- symptoms: severe metabolic disturbances, nausea, vomiting, muscular cramping, cerebral edema, possible death
What is the result of hypotonic hydration?
net osmosis of water into tissue cells and cell swelling
how is hypotonic hydration treated?
hypertonic saline
What is Edema?
atypical accumulation of interstitial fluid, resulting in tissue swelling (only volume of interstitial fluid is increased)
What are the symptoms of Edema?
- impairment of tissues by increasing distance for diffusion of oxygen and nutrients from blood into cells
What causes edema?
- increased fluid flow out of blood or decreased return of fluid to blood
