The Kidney Flashcards
If GFR is too low then….. A) ….filtrate moves too quickly and is not reabsorbed B) ….filtrate backs up to the kidneys C) ….filtrate moves too slowly and too much is reabsorbed D) ….Blood pressure is too low
C) ….filtrate moves too slowly and too much is reabsorbed
what substance has a plasma clearance rate of 0
glucose because it is all reabsorbed
where does most of acid base balance take place
proximal convuluted tubule
describe the blood supply of the kidney
renal artery carries blood to the kidney renal vein carries blood away these are separated by the glomerular and peritubular capillary beds
What is the order (from outside in) of kidney layers A) cortex, medulla, pelvis B) pelvis, cortex, medulla C) Cortex, pelvis, medulla oblongata D) cortex, medulla oblongata, pelvis
A) cortex, medulla, pelvis
what else can be used to determine GFR
creatinine , the end product of muscle metabolism
describe the basement membrane
acellular network of collagen and glycoproteins, glycoproteins are negatively charged to repel negative proteins including albumin (smallest plasma protein)
what is the nephron and where is it situated
the smallest functional unit of the kidney, situated in the renal cortex and the medulla
what is plasma clearance
the volume of plasma cleared of substance per minute
what are the 3 layers that separate the glomerulus and bowman’s capsule are why are they needed
glomerular capillary wall basement membrane inner layer of bowman’s capsule ensures only very small particles can pass through to the bowman’s space
Which of these is not a function of the PCT? A) Reabsorption of glucose, amino acids and ions B) Secretion of some toxins & urea C) Reabsorption of H+ D) Recovery of bicarbonate ions
C) Reabsorption of H+
when is plasma clearance lower than GFR
when a substance is filtered and reabsorbed and not reabsorbed
what substance has a plasma clearance rate of 0
glucose because it is all reabsorbed
how does HCO3- get into the capillary from the proximal tubule
Na+/HCO3- symporter in the basolateral membrane HCO3- moves down cg, this powers Na+ to move against cg
what is plasma clearance
the volume of plasma cleared of substance per minute
how does HCo3- get reabsorbed into distal tubule
Cl-/HCO3- antiporter HCO3- exchanged for Cl-
- A fit and healthy 21 year old male Medical Science student with normal kidneys decreases his intake of dietary sodium by half over a period of two months. Which of the following would be expected to be increased in response to this restriction of dietary sodium? A. Arterial pressure B. Extracellular fluid volume C. Release of Atrial Natriuretic Peptide (ANP) D. Release of renin E. Sodium excretion
Answer: D Learning Point: Fluid Homeostasis
What is the role of a macula densa cell? A) Monitor Na+ and control GFR B) Monitor osmolality in the collecting duct C) Control the vasodilation/constriction of the nephron D) Increase ADH secretion
A) Monitor Na+ and control GFR
what else can be used to determine GFR
creatinine , the end product of muscle metabolism
What is the order of the structures of the nephron? A) Bowmans Capsule, DCT, Loop of Henle, PCT, Collecting Duct B) Loop of henle, PCT, DCT, collecting duct C) Bowmans capsule, PCT, loop of henle, DCT, collecting duct
C) Bowmans capsule, PCT, loop of henle, DCT, collecting duct
8 parts of the nephron
- glomerulus 2. bowman’s capsule 3. proximal convoluted tubule 4. descending loop of Henle 5. ascending loop of Henle 6. Distal convoluted tubule 7. connecting and cortical collecting tubules 8. collecting duct
Where would ACE inhibitors intervene? A) HMG-CoA –> Mevalonate B) Ang 1 –> Ang 2 C) Angiotensinogen –> Ang 1 D) Renin
B) Ang 1 –> Ang 2
What effect does vasopressin have? A) Increases calcium reabsorption B) Stimulates production of aquaporins C) Natriuresis D) Increases GFR
B) Stimulates production of aquaporins
- The kidney secretes a protein that triggers a cascade which regulates blood sodium concentration and blood pressure. What is the name of this protein?
A. Angiotensin II
B. Angiotensinogen
C. Erythropoietin
D. Renin
E. Vasopressin
Answer: D Learning point: function of the kidney
what increases GFR
increased blood pressure and hydrostatic pressure in the glomerulus caused by vasodilation of afferent arteriole / vasoconstriction of efferent arteriole
when is plasma clearance = GFR, example of such substance
when a substance is filtered but not reabsorbed e.g. inulin
describe hydrostatic pressure
the pressure exerted by fluid on the capillary walls of the glomerulus or walls of the bowman’s capsule
where is carbonic anhydrase and what does it do
in the renal tubule, converts carbonic acid into H2O and CO2
Which of these corresponds to a GFR control system which effects the glomerular capillary vasoconstriction/dilation A)Tubuloglomerular Feedback B)Sympathetic innervation C)Myogenic autoregulation
B)Sympathetic innervation
Roughly, on average, how much urine do kidneys form each minute? A) 115 ml/min B) 2 l/min C) 50 ml/min D) 500 ml/min
A) 115 ml/min
What organelle is particularly present in the PCT cells? A) Chloroplasts B) Rough ER C) Golgi Apparatus D) Mitochondria
D) Mitochondria
Where is aldosterone released from? A) the hypothalamus B) the anterior pituitary C) the kidney D) the adrenal cortex
D) the adrenal cortex
when is plasma clearance = GFR, example of such substance
when a substance is filtered but not reabsorbed e.g. inulin
Which of these is not a part of the renal corpuscle? A) Basal Lamina B) Glomerulus C) Afferent Arteriole D) Bowmans Capsule
C) Afferent Arteriole
Describe the effect of ANP….
Decreases blood Na- Decreasing blood pressure and volume –> by counteracting ang 2
describe the glomerular capillary wall
a single layer of flattened epithelial cells perforated with fenestrations
what is the renal corpuscle
glomerulus and bowman’s capsule
Which of these corresponds to a GFR control system which uses macula densa cells A)Tubuloglomerular Feedback B)Sympathetic innervation C)Myogenic autoregulation
A)Tubuloglomerular Feedback
Which structures are the principle detectors for RAAS A) Macula Densa cells B) Renal corpuscle C) Juxta-glomerular D) Granular cells
C) Juxta-glomerular
what causes metabolic acidosis
dietary input of H+ exceeds H+ excretion e.g. Atkins diet ketoacidiosis, type 1 diabetes
how is H+ secretion similar and different in the distal convoluted tubule to the proximal
both tubules use ATPase pumps to pump H+ into tubule distal tubule uses a K+/H+ antiporter whereas Na+/H+ anti porter used in proximal tubule
what is colloid osmotic pressure
the pressure exerted by albumin colloids on the glomerulus the proteins generate oncotic pressure that tries to hold water back in the glomerulus
what is the function of the renal tubules
they convert glomerular filtrate into urine
Which of these corresponds to a GFR control system which causes vasoconstriction/dilation of the afferent arteriole in response to BP A)Tubuloglomerular Feedback B)Sympathetic innervation C)Myogenic autoregulation
C)Myogenic autoregulation
Diabetes is an example of a condition which typically has: A) too high GFR B) too low GFR C) No GFR
A) too high GFR
blood supply to glomerulus
receives arteriole branches from the renal artery afferent arteriole brings blood in efferent arteriole takes blood out
what is plasma clearance a measure of
GFR
what causes respiratory alkalosis
hyperventilation, excess artificial ventilation
when is plasma clearance higher than GFR
when a substance is filtered and secreted but not reabsorbed
what are the two types of loops (of henle)
Juxtamedullary and Cortical
what is plasma clearance a measure of
GFR
what causes respiratory acidosis
hypoventilation and respiratory depression CO2 retention, elevated H+
what causes metabolic alkalosis
excessive vomiting of acidic stomach contents, too many bicarbonate antacids
what is the renal hilium
region of the kidney where renal artery, vein and ureter pass
If a lady has proteins present in their urine, which could this not indicate out of the following? A) she’s pregnant B) she’s got a fever C) she’s got high blood pressure D) she’s got high GFR
B) she’s got a fever
What is the epithelium lining the PCT?
Cuboidal (with brush border)
when is plasma clearance higher than GFR
when a substance is filtered and secreted but not reabsorbed
what happens to H2o and co2 produced in renal tubule
diffuses into epithelial cell and combine to make H2CO3 which is broken down by carbonic anhydrase into H+ and HCO3-
when is plasma clearance lower than GFR
when a substance is filtered and reabsorbed and not reabsorbed
describe the inner layer of the Bowman’s capsule
made up of Podocytes which are a special kind of epithelial cell with foot like projections that wrap around capillaries of glomerulus filtration slits between Podocytes which filter blood
how is acidosis prevented
secretion of H+/reabsorption of HCO3-
what is the glomerulus
a capillary network that is the main site of filtration
how does H+ get back into the proximal tubule
ATPase pump or Na+/H+ antiporter on the APICAL membrane
what 3 things does GFR depend upon
- net filtration pressure (difference between hydrostatic and colloid osmotic pressure ) 2. glomerular surface area 3. permeability of glomerular membrane
what are the forces involved in glomerular filtration
hydrostatic pressure and colloid osmotic pressure
