RETAKE - Midterm 4 Flashcards
Topic 40. Basics of physiokogical functions of the kidney
- Filtration - a. EFP b. permability of barriers
- Reabsorption - small fraction 0,5%-1% becomes urin cause of reabsorbtion
- Secretion - Plasma (leaving the glomerulus)-> Efferent arteriole -> further substances –> Lumen at site of the peritubular cappilaries. Trans/paracellular
- Excretion= URINATION, result of filtration. as a result of.1,2,3 in the end of tubular system = 4. Secondary filtrate of 4.
Extretion investigated: CLEARANCE
Function
1.) Maintaining the homeostasis - Isovolemia
… Elimination of H+, regulatiob of Acid/base equilibrium-> isohydria
-
2.) Excretory function: eli of natural by products, medicines, toxic materials
3.) Regulates circulation -> Angiotensin II synthesis
4.) Endocrine organ:
- Formation blood(erythropoetin),
- Bone metabolism(d-hormone),
- Heat prod (activation of.thyroud gland hormones)
Functional unit: Nephron!
Topic 41- Glomerular filtration rate (GFR), extraction, clearance
GFR
- GFR - Amount of filtrate produced per unit time by all of the nephrones from both kidneys.
- Measurement: INULIN - Only filtrated (Dog-Creatinine)
- Autoregulation: Constant! = Tubulo-Glomerular feedback. MACULA DENSA
- Extraction = E= (Pa-PV)/Pa
- The ability of the kidney to ELI a substance from a organism.
- Whole kidney or nephron
- Max and Min extraction DRAWING E=1 and E=0 - Clearance = C=U/P*V
- To investigate EXTRACTION
- Inulin (entirely filteres) = GFR = Clearance
- PAHA (enterely secreted) = RPF = Clearance
- Clearance of
PAH
INULIN
UREA
GLUCOSE
Topic 42. Renal Plasma flow (RPF), Filtration fraction
-Renal plasma flow -> Para-Amino-Hyppuric Acid
- Amount of plasma flowing through the kidney(RPF)
- Based on ficks law (conservation of matter)
Drawing
- Clearance: Filtered and Excreted = PAH
- RPF=U*V/(Pa-Pv)
- Autoregulation (GFR & RPF)
- Renal Blood Flow (RBF)= RPF/1-HLc = 1200 ml/min
- Distribution of BF in tissue layers
Topic 43: Transport process in the proximal tubule
- 70% filtered
- Permable to manny subst, but imperbable to: Creatinine
Urea
HCO3-
Proteins
REABSORPTION OF NA+ & INDIRECTLY HCO3-
SECRETION OF H+ (into lumen)
AQP-1 Channels - allow free movement H2O
DRAWING
1.) The basolateral Na+/K+ ATPase pump =
Main energy source for SECONDARY active trasport: Glucose & Amino acids
- Moves Na+ from tubular cells –>
Interstitium –> Cells
2.) The secreted H+ –> CO2 & H20 w/ luminal HCO3- in the precense of CARBONIC anhydrase
3.) CO2 Diffuses back into the tubular cell –> Transformed to HCO3- –> Interstitium by (Na+/3HCO3- co trasporter
GLUCOSE & AMINO AC: 100% withdrawn from proximal tubule + Na+ by the secondary active symport of Na+/K+ ATPase pump
UREA= ca 1/2 of urea passively reabsorbed
PROTEINS - some –> Lumen, majority of these get back to the tubular cells = PINOCITOSIS
Topic 44: Transport in loop of henle & Distal loop
1.) Decending part of Henle loop (DTL- Thin dec)
High permability
2.)Thick ascending limb of Henle loop (TAL)
Reabsorbs 25% of filtered substances
Symport protein: Na+/K+/2cl- transporter
Furosemid sensitive
Na+/K+ ATPase pump, pumps Na+ from the cell to the interstitium (reabsorbtion), and from the interstitium to the cell: aginst conc. gradient
3.) TAL is Impermable to WATER and Urea! -> lumen= hypoosmotic.
K+ & Cl- will passively leave the cell at basolateral side. Na+ is eliminated here also by a very active ATPase pump
4.) DCT - NaCl withdrawal/reabsorbtion takes place.
Na+/cl- symport protein absobes a further 5% of filtered Na+ on luminal side .
- Can be inhibited by TIAZIDE derivates = Causes DIURESIS-> urination
- Cl carried out by a special K+/cl- cotransporter
Ca2+ transport directly by Parathormone (PTH)
DRAWING
Topic 45: Transport in distal CNT and collecting tubule (CCT/MCT)
The formation of the hormonally regulated final URIN takes place.
- CNT, CCT = Mineralcorticoid dependent Na+ reabsobtion.
- CCT= ADH-dependent water reabsorbtion
- MCT= ADH- delendent water and urea.reabsorbtion, ANP-dependent Na+ excreton
- Regulation of acid/base and K+ BALANCE
- Mineralcorticoid dependent Ma+/K+ transport
- Active water transport
- Acid-base balance
- K+ transport
Topic 46: Osmoregulation in kidney, the countercurrent system
- Osmotegulation
- Hyperosmosis
- Hypoosmosis - ADH- Mechanism
- The countercurrent system
Responsible for creation and maintainance of the osmotic layering. (Countercurrent multiplyer & exhange mechanism) - Osmotic gradient of the kidney
- Factors creating the osmotic gradient
Vasa recta=countercurrent+Exhange - Effect of the osmoticgradient-possible change
5stk - Clearance of free water
Topic 47. The.maintance of isosmosis, the ADH mechanism
ANTI DIURETIC HORMONE
- Reduced volume as a result of a decreased fluid or injury = DEHYDRATED
1. ) Conc of salt dissolved in blood increases = Osmotic pressure rise = Reseptors in hypothalamus -> Osmotic pressure shift -> Trigger the posteriour lobe of pituary to activate ADH
2. ) At same time- Thirst senter in Hypothalamus responds -> Stimulating ADEQUATE STIMULUS = Extra cellular HYPER OSMOSIS
3.) Role of ADH maintaining isosmosis
A- Experimentaly perfusing kidney -> hypoosmotic urine. Lack.of endocrine mechanisms: ADH readjusts ISOSMOSIS
B- Damaged hypothalmic ADH secteting locus
-> HYPOOSMOTIC Urine. DIABETES
C- INCREASED DIURESIS Following extra H20 load -> BLOCKED by ADH
D- HYDROPENIA result in immeditiate blood: ADH INCREASE
ADH mechanism of action: level: CNT distal + CD
- Result: Resets H2O permability (rebsobtion)
Osmoregulation
- Hyperosmosis
- > Isoosmotic hyperosmosis
- Hypoosmosis: ADH innhibition
- > Isoosmotic hypovolemia
VERNEYS EXPERIMENT - DIURESIS (DOG)
Topic 48. The maintanance of Isovolemia: Reninangiotension system, ANP, Aldosterone
- Volume regulation: ISOVOLEMIA
- Renin Angiostin System (RAS)
effects:
- Renin
- Angiotensin I
- Angiotensin II
- Angiotensin III
ANP figure
Other hormonal regulations:
- Prostaglandings -> Strong vasodilator
- Kalikrein-kinin system -> Strong vasodilator, Result in Bradykinin production
Aldosterone
- most importaint member of mineralocorticoids
- Steroid hormone (prod: zona glomruloza, adrenal cortex)
- Key enzyme: 18-aldolase
- MAIN EFFECT: Na+ reabsorbtion & K+ excretion
essential in the sodium and water retention
- ADH–>Primary role: setting plasma osmolarity
- Aldosterone–> Regulate the entire Na+ content of the body (EC volume) as a member of RAS.
- Independent role: Keep K+ conc of plasma within limits.
- Mainsite: DCT + CCT and collecting ducts.
ANP
- Atrial Natriuretic Peptide
Secreted in cardiac atrium
Function: Increased Na+ excretion
Topic 49 The process of Urination
- ) Urin:
- Produced in kidney continiously
- Pericordial process
- Faciliated - kept in urinary bladder - urination takes place = Micturation
2.) Urinary process: Figure Rythmical contraction: Calyx -> pelvis Speed 2-3cm/s Normaly no urinary reflux
3.) Regulation
- Emptying bladder - Controlled by PONS -> mechanoreceptors in the bladder.
- Execution carried out by:
Lumbal (Sympathethic)
Sacral ( Parasympwthetic)
Appropriate somatic motor center (m. abd, perineum, outher spincether)
A. Saturational
B. At urination
