Lecture 14 Flashcards
which structures increase the absorptive area of proximal convoluted tubule cells?
Microvilli
In the kidney, the process by which fluid and solutes from the tubular fluid are reclaimed and returned to the blood is called tubular ______.
reabsorption
Sodium is transported into the cells of the PCT by a protein that simultaneously moves it and another solute in the same direction. This type of transport protein is called a(n) ______.
symport
The PCT reabsorbs water at a constant rate known as what?
Obligatory water reabsorption
The accumulation of reabsorbed fluid on the basal side of the epithelial cells creates a high tissue fluid pressure that drives water ______ the peritubular capillaries.
into
Which region of the nephron is adapted for reabsorption, as seen in its length and prominent microvilli?
Proximal convoluted tubule
When the transporters within the proximal convoluted tubule are saturated and no additional solute can be reabsorbed,which of the following has been reached?
Transport maximum
Where does most tubular reabsorption take place?
In the proximal convoluted tubule
what is tubular secretion? (explain)
renal tubule extracts chemicals from capillary blood and secretes them into tubular fluid
What is tubular secretion?
The movement of water and solutes from the blood into the tubular fluid
An antiport transports sodium into the cells of the PCT while pumping hydrogen ions out. What hormone activates this transport?
Angiotensin II
Choose all the solutes that are reabsorbed from the nephron loop.
- potassium ions
- sodium ions
- glucose and amino acids
- water
- chloride
Na+, K+, Cl-
Potassium ions
Sodium ions
Chloride
Water is reabsorbed through specialized water channels called ______.
aquaporins
Choose all the hormones that regulate the amount of water and salt reabsorbed by the DCT and collecting duct.
- epinephrine
- antidiuretic hormone
- aldosterone
- natriuretic peptides
- angiotensin converting enzyme
aldosterone
natriuretic peptides
antidiuretic hormone (ADH)
parathyroid hormone (PTH)
What are the mechanisms of peritubular capillary absorption?
Osmosis and solvent drag
Which defines the transport maximum?
It is the upper limit of the rate solute can be reabsorbed
the hormone ___ causes increased reabsorption of sodium (and the water that follows) and secretion of potassium from the later segments of the renal tubule.
aldosterone
Aspirin, penicillin, and other drugs are cleared from the blood via the kidneys by which of the following processes?
tubular secretion
why does the heart secrete natriuretic peptides?
heart secretes natriuretic peptides in response to high BP
natriuretic peptides lower BP
excrete more salt and water in urine –> reduce blood volume and pressure
what are the effects of atrial natriuretic peptides?
1) dilate afferent arteriole and constrict efferent arteriole –> increase GFR
2) antagonize the renin-angiotensin-aldosterone mechanism by inhibiting renin and aldosterone secretion
3) inhibit the secretion of antidiuretic hormone and its action on the kidney
4) inhibit NaCl reabsorption by the collecting duct
Which leads to an increased secretion of natriuretic peptides?
increased blood pressure
The primary function of the nephron loop is to generate a medullary extracellular fluid (ECF) osmotic gradient that allows for what?
The concentration of urine
Antidiuretic hormone is secreted in response to _____.
dehydration
loss of blood volume
rising blood osmolarity
What is the primary function of the distal convoluted tubule and collecting duct?
The reabsorption of water and salts
What is the role of the collecting ducts?
To adjust the concentration of urine
The accumulation of reabsorbed fluid on the basal side of the epithelial cells creates a high tissue fluid pressure that drives water ______ the peritubular capillaries.
into
Antidiuretic hormone increases water permeability of the collecting ducts by altering the number and location of membrane proteins called ______.
aquaporins
Which renal tubule segments are influenced by aldosterone?
aldosterone acts on:
- thick segment of the ascending limb of the nephron loop
- DCT
- cortical portion of the collecting duct
Which renal tubule segments are influenced by aldosterone?
- collecting duct
- proximal convoluted tubule
- ascending limb of nephron loop
- descending limb of nephron loop
- distal convoluted tubule
Collecting duct
Ascending limb of nephron loop
Distal convoluted tubule
The ___ loop of the nephron acts as a countercurrent multiplier.
nephron
Which is an effect of atrial natriuretic peptide?
Decreased sodium reabsorption
The hormone that makes the collecting duct more permeable to water, thus increasing its reabsorption, is ______.
ADH
What is the importance of the medullary ECF osmolarity gradient?
It allows the production of very concentrated urine.
Hormones can alter the amount of water reabsorbed during urine production, allowing the production of either concentrated or dilute urine. This is the role of the ___ duct.
collecting
How does the ascending limb of the nephron loop shift sodium, potassium, and chloride into the ECF?
Active transport
How does antidiuretic hormone affect the permeability of the collecting ducts to water?
It increases their permeability.
The salts in the medullary ECF were transported from which limb of the nephron loop?
Ascending
Which segment of the renal tubule acts as a countercurrent multiplier?
nephron loop
Which leads to an increased secretion of natriuretic peptides?
Increased blood pressure
The osmolarity of the ECF deep in the renal medulla is ______ than that of the ECF of the renal cortex.
higher
As fluid flows down the water-permeable descending limb of the nephron loop, the osmolarity of the tubular fluid is ______.
increasing
What is the source of the salts that contribute to the high osmolarity of the medullary ECF?
The active transport of Na+, K+, and Cl- from the ascending limb of nephron loop
The ___ loop of the nephron acts as a countercurrent multiplier.
nephron
How does the ascending limb of the nephron loop shift sodium, potassium, and chloride into the ECF?
Active transport
