Urinary System 1 Flashcards
what are the four main components of the urinary system
kidneys
ureters
bladder
urethra
what 5 things are happening during the filtration system
1.) elimination of metabolic wastes
2.) regulation of ion levels
3.) regulation of acid-base balance
4.) regulation of blood pressure
5.) elimination of biologically active molecules
what are the four main functions of the kidneys
1.) filter blood
2.) formation of calcitriol
3.) production and release of erythropoietin
4.) potential to engage in gluconeogenesis
what does calcitriol do
increases absorption of calcium from small intestine to increase blood calcium concentration
what does erythropoietin do
stimulates red bone marrow to increase red blood cell production
what is gluconeogenesis
making of glucose from noncarbohydrate sources
helps to maintain glucose levels
between which vertebrae are the kidneys located
T12 and L3 (in the retroperitoneal)
what are the functions of the fibrous capsule of the kidney
maintains kidney’s shape
protects it from trauma
prevents pathogen penetration
what does the perinephric fat of the kidney do
cushions and supports kidney
what does the renal fascia of the kidney do
anchors kidney to surrounding structures
what does the paranephric fat of the kidney do
cushions and supports kidney
what is renal ptosis
sagging of kidney due to loss of adipose
usually occurs in those with very little fat
ureter may kink and block urinary flow - renal failure
define hydronephrosis
swelling of the kidney caused by urine backup
what is renal agenesis
failure to develop a kidney
usually unilateral
what is a pelvic kidney
developing kidney fails to migrate from pelvic cavity
what is a horseshoe kidney
inferior parts of kidneys are fused
what is a supernumerary kidney
extra kidney
what are the two regions of functional kidney tissue
renal cortex and renal medulla
what are the renal columns
extensions of cortex projecting into the medulla
what are the renal pyramids
portion of medulla dividing by renal columns
what is the corticomedullary junction
where the wide base of medulla meets the cortex
what does a renal lobe include
renal pyramid and portions of columns
cortex in that area as well
what does the renal sinus include
drainage area
minor and major calyces and renal pelvis
what is the sympathetic innervation of the kidney
T10-T12
innervates blood vessels and juxtaglomerular apparatus
decreases urine production
what is the parasympathetic innervation of the kidney
vagus nerve
unknown
what is a nephron and what does it include
functional filtration unit of kidney
made of renal corpuscle and renal tubule
what is a glomerulus
capillary loops
blood enters afferent arteriole
blood exits efferent arteriole
what does the capsular space between two layers of glomerular capsule do
receives filtrate which is modified to form urine
what are the three parts to a renal tubule
proximal converted tubule, nephron loop, distal convoluted tubule
what do juxtumedullary nephrons do
help establish salt concentration gradient in interstitial space
allows for regulation of urine concentration by ADH
what do principal cells do
responsive to hormones aldosterone and antidiuretic hormone
what to intercalated cells do
help regulate urine pH and blood pH
what do the granular cells of the JG apparatus do
contract when stimulated by stretch or sympathetic
make, store, and release renin
what does the macula dense of the JG apparatus do
detect changes in NaCl concentration of fluid in lumen of DCT
what is the path of tubular fluid (filtrate) once it enters the proximal converted tubule
PCT
nephron loop
DCT
collecting tubules
collecting ducts
papillar duct
what is the flow of urine
papillary duct
renal sinus
minor calyx
major calyx
renal pelvis
ureter
bladder
urethra
explain the first step of urine formation: glomerular filtration
occurs in glomerular capillaries
blood moves into glomerular through afferent arteriole
water and solutes leave blood and enter renal corpuscle due to pressure differences
substances in the corpuscle are now called filtrate
explain the second step of urine formation: tubular reabsorption
substances like water and vital solutes move from lumen of tubules and collecting ducts to blood
excess solutes, waste products, and some water stays within the tubular fluid
explain the third step of urine formation: tubular secretion
selective materials move out of blood and into the tubular fluid to be excreted
what are some characteristics of the filtration membrane
porous, thin, and negatively charged
formed by glomerulus and visceral layer of glomerular capsule
what are the three layers of the filtration membrane from innermost to outermost
endothelium, basement membrane, and visceral layer
what are some characteristics of the endothelium of glomerulus
innermost layer of membrane
fenestrated to allow substances to move through it
fenestrations are not too big so prevents large substances from moving through them
what are some characteristics of the basement membrane of glomerulus
middle layer of membrane
made of glycoprotein and proteoglycan
also restricts large plasma proteins
what are some characteristics of the visceral layer of glomerular capsule
outermost later
made of podocytes
restrict passage of most small proteins
what are some features of podocytes
make up the visceral layer of the glomerular capsule
have long processes (pedicels)
support capillary wall
have filtration slits
what are mesangial cells and what is their function
cells between glomerular capillary loops
phagocytic, contractile, and signaling properties
what gets filtered through the glomerulus
water
glucose
amino acids
ion
urea
hormones
vitamins B and C
ketones
some proteins
what are the three categories of substances in blood
freely filtered
not filtered
limited filtration
what are freely filtered things in blood
small substances like water, glucose, amino acids, and ions
pass easily through membrane
what are not filtered things in blood
formed elements and large proteins
cannot pass through filtration membrane
what are things whose filtration is limited in blood
proteins of intermediate size
usually blocked because of size or negative charge
what is the glomerular hydrostatic pressure (HPg)
blood pressure in glomerulus
pushes water and some solutes out into the renal corpuscle
60 mmHg
what are two things required for filtration to occur
larger diameter of afferent arteriole
smaller diameter of efferent arteriole
what does increasing blood pressure do to glomerular hydrostatic pressure
raises it
what is blood colloid osmotic pressure (OPg)
osmotic pressure in the blood due to dissolved solutes
draws fluid back into glomerulus
32 mmHg
what is capsular hydrostatic pressure (HPc)
pressure in glomerular capsule due to filtrate
impedes movement of additional fluid
18 mmHg
what is the net filtration pressure (NFP) equation
HPg - (OPg + HPc)
what is glomerular filtration rate (GFR)
rate at which the volume of filtrate is formed
mL/min
what is the average glomerular filtration rate
125 mL/min
what happens when you increase net filtration pressure
increased glomerular filtration rate
increased solutes and water remaining in tubular fluid
increased substance in urine
decreased filtrate reabsorption
what are the two things that alter glomerular filtration rate
changing luminal diameter of afferent arteriole
altering surface area of filtration membrane
(intrinsic and extrinsic controls)
what is renal autoregulation
a type of intrinsic control
kidney maintains constant blood pressure and GFR in spite of changes in systemic arterial pressure
functions by myogenic response and tubuloglomerular feedback mechanism
explain myogenic response in terms of the kidney
afferent arteriole’s control of its smooth muscle in response to stretch
increased blood pressure, more stretch, contraction to get it back to normal
decreased blood pressure, less stretch, smooth muscle relaxes to get it to dilate
explain the tubuloglomerular feedback mechanism
backup to the myogenic response
if blood pressure increases, NaCl in tubular fluid increases
this is detected by macula dense cells in juxtaglomerular apparatus
we get further vasoconstriction of afferent arteriole
what happens when blood pressure decreases below 80 mmHg
arterioles are at maximum dilation
decrease in glomerular blood pressure and GFR
less urine
what happens when blood pressure is over 180 mmHg
arterioles at maximum constriction
increased glomerular blood pressure and GFR
urine formation increasing
how do neural and hormonal control of the glomerular filtration work
types of extrinic controls
involve physiologic processes to change GFR
how does sympathetic stimulation effect GFR
during exercise or emergency, GFR decreases
afferent and efferent vessels constrict
renin released, angiotensin 2 is produced
mesangial cells contract which decreases surface area of glomerulus, therefore decreasing GFR
water is conserved
how does parasympathetic stimulation effect GFR
peptide hormone released from cardiac muscle cells when atria stretch
afferent arterioles relax
no release of renin, mesangial cells relax
increase in filtration surface area, increased GFR
more urine, less blood volume and pressure
