Lecture: Urinary, Kidney, Electrolyte/Acid Base Balance Flashcards
Where is the urinary system derived from?
Mesoderm
Where are the kidneys located in infants and then adulthood?
Pelvis and then moves to the abdomen (retro peritoneum)
Function unit of kidney
Nephron
Senses sodium passing in distal convoluted tube
Macula densa
Cells that make the enzyme renin
Juxtaglomerular cells
Avg force of pushing water and soluters out of the blood and across the filtration membrane. HP gc (OUTWARD PRESSURE)
55-60 mmHg
Glomerulus is made with what kind of endothelium for filtration membrane permeability?
Fenestrated endothelium (only fits 3 nm or smaller molecules)
a hormone secreted by the kidneys that increases the rate of production of red blood cells in response to falling levels of oxygen in the tissues. Controls blood pressure with renin
Erythropoietin
Account for 85% of kidneys nephrons
Cortical nephrons
play an important role in kidney’s ability to produce concentrated urine
Juxtamedullary nephrons
Glomerulus produces the ___________
filtrate
Peritubular capillaries or vasa recta _________ most of the ___________
reclaims; filtrate
Region where most distal portion of ascending limb of the nephron loops lies against the afferent arteriole feeding the glomerulus.
Juxtaglomerular apparatus
Where are macula dense cells found?
Distal convoluted tubule
Where are JG cells found?
Arteriole wall
No urination/kidney stops functioning
Anuria
Urinating less than 50 ml/ day
Oliguria
Normal urination per day
1-2 L or 1,000-2,000 ml per day
What is the kidneys MAP
93 mmHg. Less than 80 will not be able to filter properly
The 3 steps in the kidney
- Filtration
- Reabsorption
- Secretion
Take place in the renal corpuscle and produces a cell- and protein-free filtrate,
Step 1. Filtration
(dumping into the waste container)
The process of selectively moving substances from filtrate back into the blood. Takes place in renal tubules and collecting ducts.
- Reabsorption: glucose, amino acids, water, salt..
(reclaiming what the body needs to keep)
Process of selectively moving substances from the blood into the filtrate
- Secretion:
(selectively adding back to the waste container)
How much plasma is filtered through glomeruli per minute?
120-125 ml
About _____ ml of blood passes through gomeruli per min, about ______ ml is plasma
1200 ml; 650 ml
A passive process in which hydrostatic pressure forces fluids and solutes through a membrane
Glomerular filtration
The pressure exerted by proteins in the blood
Colloid osmotic pressure in glomerular capillaries OP gc
What is the avg colloid osmotic pressure in glomerular cappilaries? OP gc
(protein trying to bring back filtrate into the glomerulus) INWARD PRESSURE
30 mmHg
What is the hydrostatic pressure in the capsular space? HP cs
(pressure exerted by fitrate in the glomerular capsule) INWARD PRESSURE
15 mmHg
How is net filtration pressure found?
(HP gc) - (OP cs + HP cs) = NFP
ex: 55 mmHg - (30 mmhg + 15 mmHg) = 10 mmHg`
Intrinsic Regulation of Glomerular Filtration
Renal autoregulation:
Myogenic Mechanism
Tubuloglomerular Feedback Mechanism
In vascular smooth muscle, when afferent arteriole is stretched (pressure rises) it will contract to regulate GFR and when it doesn’t stretch (pressure drops) the muscle relaxes
Intrinsic: Myogenic Regulation
Directed by macula dense cells of Juxtaglomerular complex
Intrinsic: Tubuloglomerular Feedback Regulation
When GFR increases, there is not enough time for reabsorption and the concentration of filtrate remains high. Macula densa sense high levels of NaCl and…
Release vasoconstrictor chemicals to constrict afferent arteriole, reducing blood flow into glomerulus.
What happens when LOW FILTRATE FLOW and NaCl concentration is detected to be low in ascending loops’ macula densa cells?
Tubuloglomerular regulation senses signals to DILATE afferent arteriole to INCREASE GFR, then RENIN is released by JG cells to raise BP
Angiotensin II causes what
-Decrease efferent arteriole diameter (constricts)
-Decrease bloow flow out of glomerulus
-Increase HPgc
-Increase GFR
Angiotensin II causes what
-Decrease efferent arteriole diameter (constricts)
-Decrease bloow flow out of glomerulus
-Increase HPgc
-Increase GFR
a corticosteroid hormone which stimulates Na+ absorption of sodium by the kidneys and so regulates water and salt balance which then increases BP
Aldosterone
Once MAP drops below 80 mmHg kidneys, what kind of regulation takes over?
Extrinsic regulation; RAA or sympathetic
Effects of macula densa releasing vasoconstrictor:
-GFR decreases
-Tubular filtrate flow slows
-Reabsorption of sodium and chloride ions increase bc they have more time
Effects of macula densa releasing vasoconstrictor:
-GFR decreases
-Tubular filtrate flow slows
-Reabsorption of sodium and chloride ions increase bc they have more time
What does the macula densa do?
Monitors filtrate concentration autoregulates itself
What are the extrinsic controls for regulation?
Neural (sympathetic nervous system)
Hormonal (RAA system)
When blood pressure falls, sympathetic nerve fibers release _____ to cause vascular smooth muscles to constrict, increasing peripheral resistance and bringing blood pressure back to normal
Norepinephrine + Epinephrine (released by adrenal gland)`
Are baroreceptors a part of intrinsic or extrinsic renal regulation?
Extrinsic sympathetic nervous system controls
3 pathways to stimulate granular cells to release renin
- Symp. nervous system barocreceptors to release renin
- Activated macula densa cells
- Mechanoreceptors detect stretch (v MAP, more renin)
The slower the GFR the _______ the concentration of filtrate
Lower the concentration of filtrate
The faster the GFR the ________ the concentration of filtrate
Higher concentration of filtrate (less time to filter reabsorb)
Permeable to water, not salt
Water leaves the tubule + becomes more concentrated
Descending loop of henle
Impermeable to water, pumps out salt to space around tubule
Na+, Cl-, K+
Ascending loop of henle
If theres an increase is ADH, what happens to the collecting duct
Higher permeability to water:
Then higher concentration of urine:
Then volume of urine decrease:
Then increase bld. vol. + pressure
If theres a decrease is ADH, what happens to the collecting duct
Lower permeability to water:
More dilute urine:
Then vol. urine increases:
Then bld. vol. + bld. pressure decreases
Too high of Potassium
Hyperkalemia
Where does ADH come from?
Posterior pituitary gland
Freely filtered in glomerulus; not reabsorbed or secreted
Inulin
Clearance=
C=ml/min
Clearance of Inulin
Ci=125ml/min (normal GFR filtration)
Normal volume of urine per day
1-2 L/day
insufficient aldosterone production. A disorder in which the adrenal glands don’t produce enough hormones.
Addison’s Disease
% of H20 in body
60%
Intracellular fluid % in body
40%
Extracellular fluid % in body
20% IF + PLASMA
Most important IF cation
Na+
Most important ICF cation
K+
Normal H2O intake
2500 ml/day
Where does Renin come from?
Medulla triggers Renin to come from kidneys
Hormone that increases salt and water intake
Angiotensin 1
MAP=
Diastolic - (PP / 3)
A condition involving abnormally high levels of waste products in the blood.
Uremia
Tx of uermia
Hemodialysis (mechanically filters blood)
Urinating too frequently at night
Nocturia
Senses ECF osmolality
Osmolality
Post pit gland produces…
ADH and thirst mechanisms
Passing abnormally large amounts of urine.
Polyuria
Increased neuromuscular excitability
Hypercalcemia
Decreased neuromuscular excitability
Hypocalcemia
Hypokalemia
Muscle twitches, weakness
Hyperkalemia
Heart palpitation, metabolic acidosis
How much plasma is filtered per day
200 L /day
How much blood is filtered per min
1.25 L/min
_____ L is reabsorbed into circulation, _____ L is secreted back to eliminate as urine
197 L, 3L