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98 Cards in this Set
- Front
- Back
Function of urinary system
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To maintain proper chemical composition of blood.
Kidneys remove things that are too high in concentration |
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What maintains pH of blood
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Kidney's and lungs
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Components of urine production (4)
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1) Maintain proper ionic concentrations in plasma
2) Maintain proper pH of blood 3) Eliminate toxins 4) Maintain proper water in plasma (add/remove water) to control blood pressure |
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Nephrons are?
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Functional unit that make up kidneys
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Vasculature of Nephron
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Renal Artery-->Afferent Arteriole-->Glomerulus--> Efferent Arteriole--> Peritubular Capillary--> Venule--> Renal Vein (leaves kidney)
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Glomerulus
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Where filtration occurs
Knot of a capillary "fenestrated capillary" endothelial pores allow filtration of blood plasma. Proteins do not filter Plasma and dissolved particles filter through glomerulus |
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Tubules of Nephron
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Bowman's capsule-->Proximal Convoluted Tubule--> Loop of Henle--> Distal Convoluted Tubule-->Collecting Duct
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Reabsorption
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Things sucked out of tube, back to bloodstream
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Secretion
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Out of blood stream into tube. Seen with toxins.
Utilizes active transport. |
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Urine=
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Filtered-Reabsorbed + Secreted
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P(gr)
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Pressure of glomerular capillary
Pressure driving blood out of glomerulus 55mmHg |
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P(t)
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Tubular (capsular) pressure
15mmHg |
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P(co)
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Colloid osmotic pressure
30mmHg |
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P(f)
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Effective Filtration Pressure
10mmHg |
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What happens in nephron
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-20% of plasma is filtered at glomerulus
-99% of filtrate, reaborbed -1% of that which is filtered becomes urine |
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Glomerular Filtration Rate
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1) P(f) Effective Filtration Rate
2) Filtration Coefficient |
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Filtration Coefficient
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Under normal conditions =12.5ml/min/1mmHg P(f)
GFR= 125 ml/min- Amount of plasma squeezed out/min |
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Trouble levels of GFR
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Kidney problems when GFR below 30ml/min
'kidney function decline' @15 dialysis is needed |
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Ideal substance to monitor for GFR measurement
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Creatinine
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"Plasma Clearance Test"
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How much of substance is being filtered
Collect urine over 24 hours and blood test to see how much creatinine in blood |
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Ucr
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[Cr] in Urine--> 30mg/ml
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Pcr
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[Cr] in plasma--> 0.3 mg/ml
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Uvol
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Urine Volume--> 1800ml
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T
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Time (minute)-->1440 minutes
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Plasma Clearance Test Equation
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(Ucr/Pcr)x(Uvol/T)=125ml/min
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Results of Clearance Test leads to medicine?
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High-->Filtered/Secreted
Low-->Filtered/Reabsorbed...administer in higher does to keep in body |
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Autoregulation of GFR
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Myogenic Reflex
-In afferent arteriole -Smooth muscles within arterioles act to a stretch, by constricting |
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GFR and Blood Pressure
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-BP(UP)-->Arterioles Stretch-->Vasoconstriction--> Blood Flow Stabilized
-BP(Down)--> Arteriole Strength (Down)--> Vasodilation--> Blood Flow Stabilized -BP (DOWN,DOWN)-->Filtration (DOWN) -Kidneys stop using glomerulus |
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Reabsorption is Variable
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Differential factor composing blood composition
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Volume of Blood Filtered and Reabsorbed
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Filtered=125ml/min
Reabsorption=124ml/min Urine is 1ml/min |
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Components that are reabsorbed
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Water-99%
Sodium-99.5% Glucose-100%(normal) Amino Acids-100% If glucose/AA seen then they are in excess or there is kidney damage |
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Passive Reabsorption
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-Via specific channels
-Concentration gradients and electrical gradients are created by active transport |
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What is passively absorbed?
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Water
Urea Chloride |
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Why is water highly reabsorbed?
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-Most complex because it is last mechanism under control of a hormone
-Reabsorption is increased if ADH is not available |
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ADH?
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Anti-Diuretic Hormone
-vasopressin When ADH is high in blood, don't make as much urine. Alcohol supresses ADH--> Urinate more |
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Active Reabsorption
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Pumping components back into blood so that little of it is in urine
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Sodium Reabsorption
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80% of ATP Generation
Unique and complex process |
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Where sodium reabsorption occurs
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1) Proximal Convoluted Tubule
2) Loop of Henle 3) Distal Convoluted Tubule & Collecting Duct |
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Sodium Reabsorption in Proximal Tubule
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Sets up passive reabsorption of Chloride, Water, and Urea
-Chloride-electrical gradient -Water and Urea-Concentration Gradient |
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Sodium Reabsorption in Loop of Henle
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In ascending limb water will follow sodium resulting in concentrated urine production
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Sodium Reabsorption in Distal Tubule & Collecting Duct
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Depends on Aldosterone
Presence of aldosterone causes sodium to be reabsorbed No Aldosterone= No Absorption= No water absorption= More urine produced |
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Secretion in Urine Production
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Get things out of blood stream
Essentially is active transport backwards Uses sodium linked pumps (antiport pumps) |
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Antiport pumps in secretion
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Na/K Pump
Na/H Pump Na/NH3 Pump Various other pumps |
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Na/K Pump in secretion
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Na out/K in
Eliminates K+ |
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Na/H Pump
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Secretes H+
Maintains Blood pH |
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Na/NH3 Pump
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Ammonia (nitrogenous) is toxic to tissues
Pumped out of blood and in to tubules |
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Drug Tests
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Use Plasma Clearance Test
Normal GFR=125ml/min If urinated amount is greater than 125ml/min then drug is secreted -Antibiotics are secreted (penicillin in wartime) |
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Urine Composition
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-99% water
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Kidney Regulation
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1) Blood Osmolarity (water/electrolyte balance)
2) Blood Pressure (by regulating blood volume) Incredible water osmolarity gradient set up in loop of henle |
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Actions in Descending Loop
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Impermeable to sodium
water channels-aquaporins Becomes more concentrated as it loses water and becomes incredibly salty Losing water generates higher osmolarity to pump sodium out of ascending limb |
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Actions in Ascending Loop
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Sodium Pumps
Impermeable to Water Change of 200mOsM of sodium concentration Pumps out sodium, potassium, and chloride and filtrate becomes hyposmotic |
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"Renal Counter Multiplier"
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Makes region extremely concentrated in sodium
Reason: Since final collecting duct passes through region and water can be sucked out to concentrate urine |
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Vasa Recta
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Loop of blood vessel traveling down with loop of henle
Collects water from loop so water does not dilute sodium |
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Characteristics of Animal Urinary Tract
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Animals who must store water to survive have extremely long loops of henle and produce very concentrated urine
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ADH (part 2)
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Target cells that make up collecting duct
Collecting duct cells--> synthesis of aquaporins -ADH produced by pituitary gland -Essentially hypothalamus controls production of urine |
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Hypothalamus Responds To (3)
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Blood Osmoreceptors
Baroreceptors Angiotensin II |
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Hypothalamus Response: Blood Osmoreceptors
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Responds to osmolarity of blood and CSF (within Hypothalamus)
Trigger Hypothalamus to allow more/less urine production |
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Osmolarity Up/Down
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Up: hypothalamus-->pituitary--> ADH (UP)--> Water reabsorbed
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Osmolarity (Down)
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Hypothalamus-->Pituitary-->ADH (DOWN)-->No (less) water reabsorbed
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Baroreceptors: Hypothalamus Response
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Located in Aorta, Int. Carotid
Monitor BP No effect when BP in normal range with regards to ADH |
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-Blood Pressure (Way Up)
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--> ADH (Down)--> Water Reabsorption (Down)--> Urine (UP)
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-Water intake (UP)
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-->Blood osmolarity (Down)-->ADH (Down)--> Water Reabsorption (Down)-->Urine Volume (UP)
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-Sodium Intake (UP)
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Blood Osmolarity (UP)-->ADH (UP)--> Water reabsorption (DOWN)-->Urine Volume (Up)
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-Blood Pressure (WAY UP)
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-->(After a lot of Sodium)-->Blood osmolarity (UP)--> ADH (Way Down)--> Water Reabsorption (Way Down)--> Urine production (Way up)
*When blood pressure goes skyhigh, the hypothalamus overrides osmolarity and triggers ADH (DOWN) and Urine (UP) |
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Angiotensin II: Hypothalamus Response
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Hormone
Certain levels cause hypothalamus to produce ADH |
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After a lot of salt intake, control for Sodium is?
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Aldosterone
-Controls sodium reabsorption |
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Cells for sodium regulation
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Juxtaglomerular Cells (JG)
-Located in wall of afferent arteriole -Sensitive to changes in blood pressure -Secrete Renin |
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JG Cells respond to?
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1)Blood Pressure Directly
2)Sympathetic Nervous System |
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JG response to blood pressure
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BP (DOWN)-->JG Cells-->Renin
BP (DOWN)-->Hypothalamus--> Increase sympathetic tone--> Heart rate increases--> NorE--> JG Cells-->Renin |
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Angiotensinogen
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-always in blood; inactive
Angiotensinogen--renin-->Angiotensin I (still inactive)--ACE-->Angiotensin II (active hormone) |
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ACE?
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Angiotensin Converting Enzyme
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Angiotensin II Effects?
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1) Adrenal Gland--> Aldosterone
-Increase activity on sodium pumps -Increase sodium reabsorption -More sodium in blood, water reabosrbed, BP up 2) Vasoconstrictor (most powerful), BP up 3) Hypothalamus--> Pituitary Gland-->ADH (UP)-->BP (UP) |
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Normally seen in urine?
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Water
Electrolytes Nitrogen-Base Metabolic Bi-Products -filtered and actively secreted |
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Not normally seen in urine?
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Protein
Amino Acids Glucose |
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How protein can be found in urine?
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Too big to be filtered
Only seen in urine if: -Incredibly high blood pressure -Renal pathology causing inflammation of glomerulus: pores open wider |
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Why amino acids/glucose not seen in urine?
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- All are Actively Absorbed
-Secondary Active Transport --Use [Na] gradients to carry glucose/amino acids into blood stream (synport) |
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How amino acids/glucose can be seen in urine?
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Limited in rate they can work
-if synports are saturated, not all glucose/amino acids can be reabosrbed |
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Max Reabsorption Rate of Glucose
Max Plasma Glucose |
375mg/min
>375mg/min, saturated with glucose Max Plasma Glucose=300mg/dl, more than 300, glucose seen in blood. |
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Average Glucose in blood
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100mg/100ml, in blood 100mg/dl
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How much glucose is filtered?
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125ml/min...so all glucose can be filtered at normal level
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Diabetes Mellitis (Honey)
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Cells cannot take up glucose
Glucose found in urine Produce large volume of urine Water not reabosrbed since water follows concentraton gradient. Concentration is high in urine, no osmosis |
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Diabetes Insipidus (No Taste)
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Urine Production (UP)
Pituitary gland insufficient in ADH production Water not reabsorbed Urinate often |
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Hypertension Medication
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1) ADH Inhibitors
2) Inhibit Production of Aldosterone. ACE Inhibitors -Angiotensin Converting Enzymes -Bind ACE -Allow Vasodilation |
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Osmolarity (Down)
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Hypothalamus-->Pituitary-->ADH (DOWN)-->No (less) water reabsorbed
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Baroreceptors: Hypothalamus Response
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Located in Aorta, Int. Carotid
Monitor BP No effect when BP in normal range with regards to ADH |
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-Blood Pressure (Way Up)
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--> ADH (Down)--> Water Reabsorption (Down)--> Urine (UP)
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-Water intake (UP)
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-->Blood osmolarity (Down)-->ADH (Down)--> Water Reabsorption (Down)-->Urine Volume (UP)
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-Sodium Intake (UP)
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Blood Osmolarity (UP)-->ADH (UP)--> Water reabsorption (DOWN)-->Urine Volume (Up)
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-Blood Pressure (WAY UP)
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-->(After a lot of Sodium)-->Blood osmolarity (UP)--> ADH (Way Down)--> Water Reabsorption (Way Down)--> Urine production (Way up)
*When blood pressure goes skyhigh, the hypothalamus overrides osmolarity and triggers ADH (DOWN) and Urine (UP) |
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Angiotensin II: Hypothalamus Response
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Hormone
Certain levels cause hypothalamus to produce ADH |
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After a lot of salt intake, control for Sodium is?
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Aldosterone
-Controls sodium reabsorption |
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Cells for sodium regulation
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Juxtaglomerular Cells (JG)
-Located in wall of afferent arteriole -Sensitive to changes in blood pressure -Secrete Renin |
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JG Cells respond to?
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1)Blood Pressure Directly
2)Sympathetic Nervous System |
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JG response to blood pressure
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BP (DOWN)-->JG Cells-->Renin
BP (DOWN)-->Hypothalamus--> Increase sympathetic tone--> Heart rate increases--> NorE--> JG Cells-->Renin |
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Angiotensinogen
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-always in blood; inactive
Angiotensinogen--renin-->Angiotensin I (still inactive)--ACE-->Angiotensin II (active hormone) |
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ACE?
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Angiotensin Converting Enzyme
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Angiotensin II Effects?
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1) Adrenal Gland--> Aldosterone
-Increase activity on sodium pumps -Increase sodium reabsorption -More sodium in blood, water reabosrbed, BP up 2) Vasoconstrictor (most powerful), BP up 3) Hypothalamus--> Pituitary Gland-->ADH (UP)-->BP (UP) |
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Normally seen in urine?
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Water
Electrolytes Nitrogen-Base Metabolic Bi-Products -filtered and actively secreted |