renal part 1 Flashcards
what are the 2 main ways the kidney maintains homeostasis?
regulates or balances intake with excretion
excretes metabolic wastes and drugs
renal functions include:
Eliminate metabolic waste (e.g. urea)
Regulation of water and salts (e.g. Na+, K+, Ca++)
Removal of foreign chemicals (e.g. drugs)
Gluconeogenesis
Production of hormones
what 3 hormones do the kidneys secrete?
erythropoietin
renin
1,25-dihydroxyvitamin D
Kidney has an _____ cortex and ______ medulla
an outer cortex and inner medulla
what is the functional unit of the kidney?
the nephron
what occurs to blood in the renal cortex?
blood is filtered in the glomeruli and filtrate passes through tubule of nephron
In what section of the kidney are there portions of nephron tubules involved with concentration and collection of urine?
the renal medulla
where do nephron tubules empty into?
tubules empty into renal pelvis and then into ureter
chronic _____ requires hemodialysis
ESRD
In ESRD, Patients have reduced ability to eliminate ___________________
nitrogenous wastes
In ESRD, excess nitrogen is converted to what?
ammonium
what is the physiological effect of excess ammonium in patients with ESRD?
increase pH of oral cavity
blood is alkalized
Manifestations of renal disease include what?
ammonia breath
gingival enlargement
xerostomia
tooth problems
what tooth problems are associated with renal disease?
premature loss
narrowing pulp chambers
necrosis beneath fillings or crowns
what are the contraindications for ESRD patients
nephrotoxic drugs
increased susceptibility to bleeding due to destruction of platelets
what drugs should never be given to patients with ESRD?
nephrotoxic drugs:
tetracycline, acyclovir, aspirin, NSAIDs
trace the flow of urine through a nephron, starting with the glomerulus
1) glomerulus
2) proximal tubule
3) loop of henle
4) distal tubule
5) collecting duct
what structures make up a renal corpuscle?
glomerulus + capsule
the __________ is shared by several nephrons
collecting duct
what are the two types of nephrons that differ in the length of tubules
superficial or cortical
juxtamedullary
what are the 3 renal processes that regulate blood composition?
- filtration
- Secretion
- reabsorption
what occurs during renal filtration?
solutes (and the water they are dissolved in) pass from the blood into tubular fluid in Bowman’s space or the renal capsule
what occurs during renal secretion?
substances are transported from the blood in the peritubular capillaries into the tubular fluid
what occurs during renal reabsorption?
substances are transported from the tubular fluid into the blood in the peritubular capillaries
____________ and ___________ occur throughout the length of the tubules
Secretion and absorption
composition of the tubular fluid varies with tubular _______
region
the ________ is a dense capillary bed where filtration occurs
Glomerulus
the glomerulus is surrounded by ______________ (or renal capsule) which collects the filtrate
Bowman’s capsule
in the glomerulus, filtered blood leaves via _______ arterioles and flows into peritubular capillaries
efferent
how is blood flow through the glomerulus regulated?
1) smooth muscle contraction in afferent or efferent arterioles
2) response of the juxtaglomerular apparatus (JGA)
3) sympathetic nervous system
where is the juxtaglomerular apparatus (JGA) found?
intersection of the macula densa of distal tubule with aff. and eff. arterioles
____ secreted from juxtaglomerular cells
renin
the ____________ reabsorbs 2/3 of flitered salt and water
proximal tubule
the proximal tubule reabsorbs what molecules?
reabsorbs all filtered glucose and amino acids
what does the renal capsule drain into?
the proximal tubule
what are the 3 sections of the loop of henle?
thin descending limb
thick ascending limb (TAL)
thin ascending limb
The loop of henle is the site of ___________ multiplication
countercurrent
why is countercurrent multiplication by the loop of henle needed?
needed to produce concentrated urine
T/F: the loop of henle produces concentrated urine
FALSE
it is needed to produce concentrated urine, but the loop itself produces a dilute flitrate
where do very powerful diuretics work?
on the loop of henle
The distal tubule drains the __________
loop of Henle
what are the functions (2) of the distal tubule?
continued reabsorption
regulation of calcium
the _____________ extends from cortex through the medulla
collecting duct
the collecting duct regulates what?
regulates sodium, potassium, and water
what is renal clearance?
the rate of excretion of a solute expressed as how much per unit time (compares in to out)
____________ represents the volume of plasma from which all of a particular substance is removed to the urine, e.g. 100 ml/min
renal clearance
Renal clearance can be used to measure _____________________
glomular filtration rate (GFR)
what is the GFR of a normal kidney?
in a normal kidney, GFR (from all nephrons) is:
125 ml/min or 180 L/day
_______ and _______ are substances that can be used to measure renal clearance
inulin and creatinine
what is inulin? how do nephrons respond to it?
small polysaccharide
freely filtered and not secreted or absorbed
what is creatinine? how do nephrons respond to it?
product of muscle metabolism
freely filtered, not reasbsorbed, almost no secretion
what are normal creatinine levels in the bloodstream? when would creatinine levels be so high that they require dialysis?
Normal levels are < 1+ 0.5 mg/dl
if > 10 → requires dialysis
what are typical GFR’s for men? women?
125 ml/min (females)
90-140 ml/min (male)
Glomerular capillaries are ________
fenestated
_______ (cells) around the capillaries form filtration slits in the glomerulus
podocytes
T/F: glomerular filtrate is acellular and essentially protein-free
true
what substances are freely filtered in the glomerulus?
glucose, salts, and amino acids
what factors influence whether or not a solute will be filtered in the glomerulus?
Size
charge
the basal lamina (basement membrane) of the glomerulus is ________ charged
negatively
Filtration occurs due to ________ differences between the blood in the capillaries and the fluid in the capsule (Starling forces)
pressure
what is hydrostatic pressure?
pressure due to fluid
is hydrostatic pressure higher in the capillaries, or in the capsule fluid?
higher in the capillaries
what is oncotic pressure (π)?
pressure due to solutes in fluid (including those not dissolved)
is oncotic pressure higher in the capillaries, or in the capsule fluid?
higher in the capillaries
Net filtration pressure in the glomerulus favors filtration from _____ into the __________
from blood into the capsule fluid
_________ is affected by bloodflow into and out of the glomerulus
GFR
glomular filtration rate
T/F: renal blood flow (RBF) varies depending on systemic blood pressure
FALSE
Despite changes in systemic blood pressure, renal blood flow (RBF) remains fairly constant
because _______ remains constant, GFR remains constant
RBF
renal blood flow
what are the 2 primary mechanisms for auto regulation of the bloodflow to the glomerulus?
- myogenic mechanism
2. tubuloglomerular feedback
what causes the myogenic mechanism for blood flow auto-regulation?
vascular smooth muscle tends to contract when it is stretched
what is tubuloglomerular feedback ?
feedback from the JGA adjusts afferent arteriole diameter and, thus, GFR
diet, dehydration/hemorrhaging, and the sympathetic nervous system can effect what?
the regulation of RBF and GFR
what hormones can effect the regulation of RBF and GFR?
angiotensin II, aldosterone, and natriuretic peptide
