Lecture 1 Renal Flashcards
what are the 2 keys to maintaining homeostasis within the kidney
excrete wastes/ drugs, balance intake and secretion
5 functions of kidneys
eliminate waste like urea regulate water and salts removal foreign chemicals like drugs gluconeogenesis produce hormones
3 hormones produced by kidneys
renin
1,25 dihydroxyvitamin D
erythropotietin
what does renin do
INC in renin?
DEC in renin
renin regulates BP part of angiotensin -aldesterone cascade
INC renin INC BP
DEC renin DEC BP
what is Erythropoietin for
acts in bone marrow to stimulate production of RBCs
what is 1,25 Dihydroxyvitamin D for
regulation of Ca reabsorption
End State Renal disease can be acute or chronic which one needs dialysis
chronic ESRD requires dialysis
What does ESRD causes concerning kidney function
causes inability to excrete N wastes leading to excess ammonium
what does excess ammonium production by kidney lead to
INC blood pH- blood becomes alkalized which leads to INC pH in mouth!
ESRD oral health affects (4)
gingival enlargment (side effect of ESRD drugs)
xerostomia
tooth problems (premature loss, narrowing of pulp chambers, necrosis beneath restorations)
ammonium breath - from INC pH
what tooth problems from restricted blood flow arise from ESRD
premature tooth loss - which indicates stage of ESRD
narrowing of pulp chambers
necrosis beneath restorations
Contras for ESRD pts?
DO NOT use nephrotoxic drugs such as tetracycline, acyclovir, apsirin, NSAIDs
PTs with ESRD have a INC in what? what is this caused from
PTs with ESRD have INC in bleeding due to destruction of platelets
PTs with ESRD have INC bleeding so what drugs would you not want to prescribe to them?
aspirin and NSAIDs
position of kidney in abdominal cavity
retroperitoneal
Structure of kidney
outer cortex and inner medulla composed of many nephrons
functional until of kidney
nephron
what happens in renal cortex
blood is filtrated through glomeruli and filtrate passes thru tubule of nephron
what concentrates urine
LoH
in the medulla what do portions of the nephron do?
concentration and collection of urine
what do the tubules empty into? what does this empty in to?
tubules > renal pelvis > ureter
ureter empties in to what? this empties in to what?
ureter > urinary bladder > urethra
how many nephrons in each kidney
1.2 x 10^6
what is a nephron made of (x 5)
renal corpuscle (glomerulus + capsule) Prox tubule loop of hence distal tubule collecting duct (which is shared by several nephrons)
what is the renal corpuscle made of
glomerulus and renal capsule
two types of nephrons
superficial (cortical nephrons)
JA nephrons
describe the position and length of medullary tubules of the superficial (cortical) nephron and urine produced
the cortical nephron is mostly in the renal cortex and has short LoH which produces diluted urine
majority of nephrons are which type
superficial (cortical nephrons)
describe position and length of medullary tubules of the JA nephron, and urine produced
JA nephrons very close to medulla, have LONG LoH, and produced very concentrated urine
what are the 3 renal processes of regulating blood composition
filtration
secretion
reabsorption
what is filtration
solutes and water pass from blood into tubular fluid in renal capsule (bowmans space)
where does filtration occur and how much plasma is filtered?
filtration occurs in glomerulus capillaries where 15-20% of plasma is filtered
where does blood leaving the glomerulus capillaries go? 2 names for this are?
blood > glomerulus capillaries > peritubular capillaries (AKA vasa recta)
what is secretion
secretion if the transport of substances from blood in vasa recta into tubular fluid
what is reabsorption
reabsorption is substances transported from tubular fluid into the blood in the vasa recta (peritubular capillaries)
does secretion and absorption occur throughout the length of the entire tubule?
YES
what is the glomerulus
glomerulus is a dense capillary bed where filtration occurs surrounded by the bowmans capsule
the renal capsule surrounds the glomerulus what is the renal capsules actions
the renal capsule collects filtrate from blood entering via AFFERENT ARTERIOLES
what transports blood from the renal corpsucle into the peritubular capillaries
EFFERENT ARTERIOLES
path of blood into renal corpuscle (glomerulus)
Afferent arterioles > renal corpuscle > Efferent arterioles
how is blood flow regulated thru the glomerulus (x3)
smooth muscle contraction of afferent and efferent arterioles
JGA secretion of renin which regulates systemic BP
where the the juxtaglomerular apparatus?
the JGA is at the intersection of the macula dense of the distal tubule with Afferent and Efferent arterioles
actions of JGA? INC in Na causes what?
JGA secretes renin .
JGA senses INC in NA thus INC Renin thus INC BP
stimulation of sympathetic NS does what
reduces blood flow through the glomerulus
the Prox convoluted tubule drains the capsule what happens in the PCT
PCT reabsorbs 2/3 of filtered water and salts
reabsorbs all filtered GLUCOSE AND AAs
some diuretics act here
after the PCT is the Loop of Henle what is this divided into? and describe the urine makeup bc of the LoH
LoH = thin descending limb, thin ascending limb and thick ascending lim
LoH DOES NOT CONCENTRATE URINE ITSELF! makes it possible for the urine to be concentrated later
LoH produces what kind of urine
LoH produces a dilute filtrate, but is a site of countercurrent mechanisms needed to concentrate later
the distal tubule drains the LoH what is the DCT actions
DCT = continued reabsorption of solutes, REGULATES Ca, site of action for diuretics
What is the site of action for Ca regulation?
Distal Tubule!!
Collecting duct collects fluid from multiple nephrons describe the collecting ducts site and action
Collecting duct extends from kidney context into the medullar
regulates Na, K, and H2O
diuretics act here
what is renal clearance
Renal clearance is the rate of excretion of a solute through the kidney
represents the volume of plasma from which all of a substance is removed to urine
helps monitor renal function
Renal clearance is used to monitor Glomerular Filtration rate (GFR) based on what 3 assumptions
substance is NOT secreted
substance is NOT reabsorbed
substance is freely filtered
what is the normal GFR from all nephrons
125 ml/ min
180 L/ day
what are 2 substances that can be used for assessing GFR
inulin and creatinine
what is Inulin
Inulin is a small polysaccharide freely filtered and NOT secreted or absurd
what is creatinine
creatinine is a product of muscle metabolism FREELY FILTERED, NOT reabsorbed and ALMOST NO secretion
Normal levels
female GFR
125 ml/ min
male GFR
90 -140 ml/ min
Glomerular capillaries are fenestrated and podocytes around the capillaries have filtration slits describe the filtrate going thru
Filtrate will be ACELLULAR and protein free
Glucose, salts, AAs are freely filtered
42 A not filtered
Charge matters! (negative charged moderate sized particles limited bc BM is neg charged)
where the route of filtrate
blood side > fenestrations in endothelium > Basement Membrane > filtration slits (bowman capsule) >
what are Starling forces?
Starling forces is why filtration occurs due to the pressure differences between the blood in capillaries and the fluid in the capsule
What is pressure due to fluid?
Higher in what?
Pressure due to fluid = hydrostatic pressure
P in capillaries > P in capsule fluid
what is pressure due to solutes in fluid?
higher in what?
oncotic pressure is pressure due to solutes including those NOT dissolved
Oncotic pressure in capillaries > capsule fluid
Net filtration pressure favors what
filtration from blood into capsule bc GFR = (Pgc - Pbs) - (Oncotic cap - Oncotic BS)
Oncotic pressure in the bowman space is always what?
0!!
what two intrinsic mechanisms auto regulate blood flow through the glomerulus
myogenic mechanism and tubuloglomerular feedback
what is the myogenic mechanism
what happens during INC in sympathetic stimulation? DEC in Symp?
contraction and relaxation of smooth m affect BP thus affects RBF and GFR
Thus Inc Symp = contraction = INC Bp = DEC RBF = DEC GFR
DEC Symp = dilation = DEC BP = INC RBF = INC GFR
describe the tubuloglomerular feedback
feedback from the JGA adjusts afferent arteriole diameter and thus GFR
INC in GFR thus INC in NaCl in tubulular fluid > ? > ? finish path
INC GFR > INC NaCl tubular fluid > INC NaCl at macula densa > INC resistance in afferent arteriole > Dec GFR
what extrinsic mechanisms can regulate RBF and GFR
diet, dehydration/ hemorrhage, Symp NS, angiotensin alderstone cascase and natriuretic peptides
dehydration and hemorrhage leads to what of GFR
DEC GFR
INC sympathetic does what to GFR
INC BP so dec GFR (Symp limits production of urine)
