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98 Cards in this Set

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