excretory system
DESCRIPTION
EXCRETORY SYSTEM. Function. Disposes of wastes & excess ions Regulates volume & chemical makeup of blood by maintaining proper balance between water & salts, acids & bases. UREA. Produces renin to regulate blood pressure & kidney function - PowerPoint PPT PresentationTRANSCRIPT
EXCRETORY EXCRETORY SYSTEMSYSTEM
FunctionFunctionDisposes of wastes Disposes of wastes
& excess ions& excess ionsRegulates volume & Regulates volume &
chemical makeup of chemical makeup of blood by maintaining blood by maintaining proper balance proper balance between water & between water &
salts, acids & basessalts, acids & bases UREA
Produces Produces reninrenin to regulate to regulate blood pressure & kidney blood pressure & kidney functionfunction
Produces Produces erythropoietinerythropoietin to to stimulate RBC production stimulate RBC production in bone marrowin bone marrow
Metabolizes Metabolizes vitamin Dvitamin D to its active formto its active form
OrgansOrgans
KidneysKidneysUretersUretersUrinary Urinary BladderBladder
UrethraUrethra
Anatomy of KidneyAnatomy of KidneyBean-shapedLocated between 12th thoracic
vertebra and 3rd lumbar vertebra (partial protection)
Rt. kidney lies lower than leftConcave cleft on medial surface
called- hilus which leads to the renal sinus
Adrenal Adrenal GlandsGlands lie lie on top of on top of each each kidney kidney
External anatomyExternal anatomysurrounded by surrounded by renal renal
capsulecapsule (protects from (protects from surrounding infection surrounding infection and trauma), and trauma),
adipose capsuleadipose capsule (holds kidneys in place (holds kidneys in place and protects from and protects from trauma), trauma),
renal fasciarenal fascia (anchors). (anchors).
Internal anatomyInternal anatomyrenal renal cortexcortex - outer - outer
regionregionrenal renal medullamedulla - inner - inner
region with cone shaped region with cone shaped renal pyramidsrenal pyramids
renal renal columnscolumns separate separate pyramidspyramids
renal renal pelvispelvis - continuous - continuous with the ureter leaving with the ureter leaving the hilusthe hilus
major and minor major and minor calycescalyces
Renal pyramidRenal column
Renal calyx
Blood and Nerve SupplyBlood and Nerve Supply
renal arteries - deliver 1/4 total cardiac output to kidneys per minute
lobar arteriesinterlobar arteries arcuate arteries Interlobular arteries
Nephron (this is where the action is!)
Interlobar, Interlobular, Arcuate, Lobar, Renal veins
Renal Plexus – sympathetic nerve fibers
NephronNephron
over 1 million/ over 1 million/ kidney; kidney; filtering unitfiltering unit of of kidney; results kidney; results in production in production of urine of urine
renal corpusclerenal corpuscle - consisting of - consisting of glomerulus, glomerulus,
Bowman's Bowman's capsulecapsuleproximal proximal convoluted convoluted tubuletubule (PCT) (PCT) loop of Henleloop of Henle
distal convoluted tubuledistal convoluted tubule (DCT) (DCT)
collecting tubulecollecting tubule (urine (urine collecting duct)collecting duct)
papillary ductspapillary ducts (collection (collection of all collecting tubules)of all collecting tubules)
Nephron
1. Bowman’s Capsule
2. PCT
3. DCT
4. Loop of Henle
5. Collecting Tubule
6. Renal artery
7. Renal vein8. Interlobular artery9. Afferent artery10. Glomerulus11. Efferent artery12. Peritubule
capillaries
Kidney PhysiologyKidney Physiology
3 Steps involved in kidney 3 Steps involved in kidney filtrationfiltrationGlomerular Filtration Glomerular Filtration
PassivePassiveMechanicalMechanical
based on based on hydrostatic hydrostatic pressurepressure
enhanced by permeability of enhanced by permeability of filtration membranefiltration membrane
filtration membrane consists filtration membrane consists of 3 layersof 3 layers
porous endotheliumporous endothelium - - prevents passage of cells & prevents passage of cells & large proteinslarge proteins
thin basement membranethin basement membrane – – charged to repel charged charged to repel charged proteinsproteins
visceral membranevisceral membrane with slit-like with slit-like openings; prevents passage of openings; prevents passage of large plasma proteinslarge plasma proteins
Net Filtration PressureNet Filtration Pressure – – Glomerular hydrostatic pressure Glomerular hydrostatic pressure
+ Bowman's hydrostatic pressure + Bowman's hydrostatic pressure (opposing forces)(opposing forces)
Filtration RateFiltration Rate: rate at which fluid : rate at which fluid is forced from blood into Bowman's is forced from blood into Bowman's
capsule; dependent upon:capsule; dependent upon:- surface area- surface area- filtration membrane permeability - filtration membrane permeability
- - Net filtration pressureNet filtration pressure
- Glomerular filtration rateGlomerular filtration rate - is proportional to Net is proportional to Net filtration pressurefiltration pressure
- anything changing pressure anything changing pressure at the membrane also at the membrane also changes the GFR, therefore changes the GFR, therefore higher blood pressure = higher blood pressure = higher GFR; dehydration = higher GFR; dehydration = lower GFRlower GFR
Tubular ReabsorptionTubular Reabsorption - - reclamation of tubule contents reclamation of tubule contents difference b/t filtrate & urinedifference b/t filtrate & urine
filtratefiltrate - everything in blood - everything in blood plasma except proteins & plasma except proteins & cellscells
urineurine - wastes & unneeded - wastes & unneeded substancessubstances
reclamation begins in PCT reclamation begins in PCT (both active/passive transport)(both active/passive transport)activeactive - glucose; a.a., vit, Na, - glucose; a.a., vit, Na, Ca, Cl, K, P,; most require a Ca, Cl, K, P,; most require a carrier molecule. When all carrier molecule. When all carrier molecules are bound, carrier molecules are bound, excess are excreted into excess are excreted into urineurine
passivepassive - (diffusion, osmosis) - (diffusion, osmosis)usually tied to active usually tied to active transport of Natransport of Na
other anions move with Na to other anions move with Na to balance charges in the blood.balance charges in the blood.
The anions that move depend The anions that move depend on the blood pHon the blood pH
HH22O moves passively O moves passively (osmosis) due to its linkage to (osmosis) due to its linkage to Na+Na+
solvent dragsolvent drag occurs when occurs when filtrate becomes filtrate becomes concentrated & solvent concentrated & solvent follows the concentration follows the concentration gradient back into the bodygradient back into the bodyExplains why some Explains why some drugs & toxins are not drugs & toxins are not excreted easilyexcreted easily
Nonreabsorbed substancesNonreabsorbed substancesUrea (40% reabsorbed)Urea (40% reabsorbed)CreatineCreatineuric aciduric acid
Tubule absorption capabilitiesTubule absorption capabilities PCT PCT most reabsorption occurs most reabsorption occurs
herehere
Uric Acid
DCT DCT permeable to Na but not Hpermeable to Na but not H22OOurine concentration urine concentration
determined heredetermined heredependent on blood pressure dependent on blood pressure
or volumeor volumedependent on hormone dependent on hormone
release:release:
aldosterone - increases Na aldosterone - increases Na reabsorption & therefore Hreabsorption & therefore H22OO
ANF - opposes thisANF - opposes thissex hormonessex hormonesglucocorticoidsglucocorticoids
Tubular SecretionTubular Secretion – – Reabsorption in reverseReabsorption in reverseammonia (secreted ammonia (secreted
into the collecting into the collecting tubule from the blood)tubule from the blood)
Active process Active process Some drugs Some drugs
(penicillin)(penicillin)
PathologyPathologySuppressionSuppression - holding - holding
backbackPyuriaPyuria - tract infection - tract infectionPtosisPtosis
(hydronephrosis) - (hydronephrosis) - kinked ureterkinked ureter
PyelonephritisPyelonephritis – – kidney inflammationkidney inflammation
PyelitisPyelitis - - inflammation of pelvisinflammation of pelvis
AnuriaAnuria - no output - no output due to low pressuredue to low pressure
UrethritisUrethritis - - inflammation of inflammation of urethraurethra
CystitisCystitis- inflammation - inflammation of bladderof bladder
DysuriaDysuria- painful urination- painful urinationIncontinenceIncontinence - sphincter control - sphincter controlRetentionRetention - involuntary - involuntary
suppressionsuppressionDiabetes insipidusDiabetes insipidus – lack of ADH – lack of ADHAddison's DiseaseAddison's Disease – not enough – not enough
aldosteronealdosteroneExcess ClExcess Cl – indicate stone – indicate stone
formationformation
Excess phosphatesExcess phosphates - alkaline - alkaline urineurine
Cushing's DiseaseCushing's Disease - - hyperaldosteronismhyperaldosteronism
DehydrationDehydration – low GFR – low GFRHypotonic hydrationHypotonic hydration – “water – “water
intoxication”; Hyponatremia, too intoxication”; Hyponatremia, too much ADHmuch ADH
Renal calculiRenal calculi – kidney stones – kidney stones