Exam 4- Urinary System Flashcards
Functions of Urinary System !!!
-Excretion= filter blood to remove wastes from body fluids
-Production, storage, & elimination of urine
-Homeostatic regulation (electrolyte concentration, blood pH, fluid volume & BP, erythropoiesis)
Function/Location/Structure of Kidney
function: filter blood and produce urine
location: retroperitoneal (behind peritoneal membrane that lines abdominal cavity)
structure: three external layers-
1. renal fascia: anchor kidney in place
2. perinephric fat (adipose capsule): provide protection and padding
3. fibrous (renal) capsule: for protection
Structure of Kidney: Renal Cortex, Renal Column, Renal Medulla, Renal Pyramids, Renal Papilla, Minor Calyx, Major Calyx, Renal Pelvis, Renal Sinus
Renal Cortex: outer region
Renal Column: extension of renal cortex that passes b/w renal pyramids
Renal Medulla: inner region
Renal Pyramid: cone-shaped structure in medulla
Papilla: where renal pyramid tapers into
Minor calyx: cup-shaped tube next to renal papilla that collects urine
Major calyx: where minor calyx drain into
Renal pelvis: where major calyx drain into that empties into ureter
Renal Sinus: internal chamber that contains major and minor calyces, renal pelvis, and some adipose tissue
Function of Ureter
move urine from kidneys to bladder
Function of Urethra
move urine from bladder to exterior
Function of Urinary Bladder
stores urine
Nephron
def: main functional unit of kidney
structure:
-renal corpuscle: contains glomerulus inside and glomerular capsule surrounding glomerulus
-renal tubule: contains PCT, nephron loop, and DCT
Types of Nephrons
- Cortical Nephron: majority of nephrons; have short nephron loops
- Juxtamedullary Nephron: long nephron loops that extend into medulla. Important for concentrating the urine & reabsorbing water
Collecting System & Types
def: comes after nephron; nephrons empty filtrate (urine) & further modify it until it becomes urine
-Cortical collecting ducts: (go through cortex) receive filtrate from DCT & empty into medullary collecting ducts
-Medullary collecting ducts: empty into papillary ducts
-Papillary ducts: empty into minor calyx at renal papilla
Urea
most abundant organic waste from protein catabolism (ammonia -> urea)
Creatinine
from breakdown of creatine phosphate
Uric Acid
product of breaking down nucleic acid
Renal Failure & Dialysis
Renal Failure: results in buildup of toxic wastes
Dialysis: method to artificially filter blood
Renal Physiology !!!
- Filtration: passive movement of fluid & solutes; solutes + water go ; OUT of blood INTO filtrate
- Reabsorption: active or passive movement of water & solute; OUT of filtrate INTO blood
- Secretion: active transport of water & solutes; OUT of blood INTO filtrate
Passive Transport
diffusion (solute from high to low) & osmosis (water from low concentration to high concentration)
Active Transport
requires an energy input; pumps that need ATP to pump substances against concentration gradient
Carrier-Mediated Transport
*require protein carrier/pumps
Examples: facilitated diffusion (passive transport) & active transport
*carriers (channels) are specific & can be saturated (when saturated, they are working at max capacity & cannot move any more substances) aka, cannot pump anymore
Transport Maximus & Renal Threshold
Transport Maximus: max amount of a solute in blood that can be reabsorbed in kidneys; cannot move/reabsorb any more substances
Renal Threshold: concentration of substance before it starts appearing in urine
Renal Corpuscle
outside part is the Glomerular (Bowman’s) capsule & inside is glomerulus
Visceral & parietal layers of capsule
visceral layer: made of specialized epithelial cells (podocytes)
parietal layer: outside of capsule made of simple squamous epithelium
Podocytes
have pedicels: “feet” that wrap around glomerular capillaries to form filtration slits
-only small substances can fit through filtration slits and filter out of glomerulus; control size of substances that go in/out
Glomerular Filtration
type of passive transport driven that happens when blood goes through glomerulas, water & solutes leave the blood and enter capsular space that becomes filtrate
Only selective based on size (proteins & cells aren’t filtered)
Components of Filtration Membrane
def: what substances need to cross to come out of blood to enter filtrate
1.pores on fenestrated glomerular capillaries
2. sticky basement membrane: thin layer of gel extracellular matrix with proteins
3. podocyte filtration slits
Hydrostatic Pressure
what drives filtration; pushes water out of capillary into glomerular capsule