Ch 19 the kidneys Flashcards
This comes from the greek word enphros neaning kidney.
Nephron
Where are the kidneys situated in the body?
btw the renal cortex
What is the renal medulla?
The functional unit of the kidney
What is the Glomerulus?
bulb of capillaries surrounded by a covering
What is the Gomerulus surrounded by?
Bowman’s capsule
What does the Glomerulus contain?
Afferent arteriole and Efferent arteriole
Afferent arteriole is going…
into the glomerulus
Efferent arteriole is going….
out of the glomerulus
What is the Proximal convoluted tubule?
The tube leading from the glomerulus
What happens in the proximal convoluted tubule?
Reabsorption of H20, ions and organic nutrients via diffusion, facilitated diffusion, or active transport
What is the descending limb
Tubule that comes down away from the glomerulus
What happens in the descending limb
H20 is reabsorbed via active transport
What is the Loop of Henle
The hairpin turn of the tubule leading back toward the glomerulus
What happens in the loop f henle
NaCl reabsorption via passive transport
Why is there no H20 reabsorption in the loop of henle
due to lack of aquaporin (a common water transport channel protein)
What is the ascending limb?
Tubule that comes back up toward the glomerulus
What happens in the ascending limb?
NaCl reabsorption
What happens in the Distal Convoluted tubule?
Secretion of ions under hormonal control of aldosterone stimulating the Na+ and K+ ion pumps, acids, and drugs
What is an example of something reabsorbed in the distal convoluted tubule?
penicillin
What happens at the Juxtaglomerular apparatus?
The point at which the distal convoluted tubule makes contact with the afferent arteriole to regulate the kidney function.
By releasing the enzyme (renin) it in turn activates what?
Angiotensin protein to increase BP the kidneys maintain the pressure needed for proper filtration
In this some substances are actively moved from the blood into the nephron to regulate the acid-base pH balance of the body fluids.
Tubular Secretion
What does the glomerulus allow as far as filtration goes?
Allows diffusible materials to pass from the blood into the nephron
What are the fenestrated capillaries wrapped with?
Podocytes (footed cells)
What are the secondary processes called on the Podocytes?
Pedicels
What do the Pedicels do?
Allow filtrate to pass through filtration slits while retaining blood cells
What is absorption?
Out of the nephron into the tissues
What is secretion?
From the tissues back into the nephrons
Maintenance of extracellular volume is brought about by retaining or excreting what?
Sodium
Regulation of sodium and water output or excretion involves a complex set of intertwined processes in the
kidneys, adrenal cortex, and the blood
What are the 3 factors know of importance in the regulation of Na+ and H20
- Glomerular Filtration Rate
- The hormon Aldosterone
- Physical factors within the kidney itself
Increase in blood pressure causes podocytes to reduce what?
Capillary permeability
What are the 3 factors that effect the GFR?
- Increase in BP
- Sympathetic stimulation and vasoconstriction
- Parasympathetic stimulation
If BP is decreased in the Juxtaglomerular apparatus the the Renin Concentration is
increased
Increased GFR =
Increased Na+ excretion
Decreased GFR =
Decreased Na+ excretion
What produces Aldosterone?
zona glomerulosa of the adrenal ccortex
What does Aldosterone stimulate?
Sodium reabsorption and potassium secretion
How does Aldosterone reabsorb sodium and secrete potassium?
by the cells of the distal convoluted tubules and collecting ducts of the kidney nephrons
What increases in the DCT as Aldosterone concentration increases?
Na+
What are the 4 things that Control the secretion of aldosterone?
- Na+ concentration in blood plasma
- K+ concentration in blood plasma
- ACTH concentration
- Renin secretion from the kidneys
When sodium concentration increases in the plasma what also increases?
Intracellular concentration of sodium
Increased sodium concentration =
decreased rate of Aldosterone secretion
Increased potassium concentration =
increased rate of aldosterone secretion
Decreased concentration of sodium in the plasma WITH an increased potassium concentration =
an additive affect on Aldosterone
Increased concentration of sodium and potassium in the plasma =
a net affect on Aldosterone that is the algebraic sum of the two.
The physical factors in the kidneys involve changes in what?
protein concentration in the plasma of the peritubular capillaries
What results in Hyponatremia?
Not consuming enough sodium in the diet, excreting too much, or being overhydrated.
How can someone get a low sodium level??
When body produces too much antidiuretic hormone which signals the kidneys to retain water
What disorders can arise from Hyponatremia?
Pneumonia, stroke, drugs, heart failure, liver failure, kidney disorders
Having a low sodium levels can cause what?
confusion, dorowsiness, muscle weakness, and seizures
What is Hypernatremia?
A high sodium level
What is Hypernatremia caused by?
dehydration or use of diuretics
What are the symptoms of hypernatremia?
weak and feel sluggish
Having high sodium levels can cause what?
confusion, paralysis, coma and seizures
If the sodium level is slightly high it can be lowered by drinking fluids. true or false
true
What is Hypokalemia?
Low potassium levels
What causes Hypokalemia?
caused by use of a diuretic
What do diuretics do?
Cause the kidneys to excrete more potassium in urine
What is another way you can get hypokalemia?
having diarrhea or vomiting for a long time
What happens to the body if the potassium levels are low for a long time?
the body tends to produce less insulin.
What are the side effects of a low potassium level?
fatigue, confusion, muscle weakness and cramps.
What can a VERY low potassium level cause?
paralysis and abnrmal heart rhythems
In what people do heart rhythms tend to develop even if their potassium level is even moderately low?
People who take digoxin. (treatment for heart failure)
What is Hyperkalemia?
a high potassium level
Which is more dangerous a high or low potassium level?
A High potassium level
What happens to the kidneys if there is high potassium levels?
kidney failure
What is a drug that can help lower the potassium level in the kidneys?
Diuretic called spironolactone and angiotensin-converting exzyme inhibitors
What can be the first symptom of high potassium levels?
abnormal heart rhythm
What can help with the diagnosis of high potassium levels?
ECG
Excretion = what?
Filtration - reabsorption + secretion
Clearance of X =
[X]plasma (mg/mL plasma)
filtration of X = what?
[X]plasma X GFR
Inulin clearance = what
[inulin]plasma
GFR = what?
inulin clearance
During micturiton first the stretch receptors fire then what happens?
Parasympathetic neruons fire. Motor neurons stop firing. Then smooth muscle contracts. internal sphincter passively pulled open. External sphincter relaxes.
