RENAL PHYSIOLOGY Flashcards
RENAL FUNCTIONS
a. renal blood flow
b. glomerular filtration
c. tubular reabsorption
d. tubular secretion
e. Erythropoietin production
How many nephrons each kidney?
1-1.5 millions
Basic structural unit of the kidney
NEPHRON
Two types of nephron and their functions
1) Cortical nephrons - removal of waste and reabsorption of nutrients; 85% of nephron
2) Juxtamedullary nephrons - concentration of urine; have longer hoops of Henle; 15% of nephron
Blood flow in KIDNEY
Afferent arteriole –> efferent arteriole –> peritubular capillaries –> vasa recta
Kidney receives how much/many of blood?
20-25% of blood
This surrounds the proximal and distal convoluted tubule
Peritubular capillaries
Vasa recta is located at?
Located at the adjacent of ascending and descending loop of Henle
Where loop of Henle is located
Medulla
This is where urine formation begins
GLOMERULUS
How many coils of capillary lobes does glomerulus have?
8
Forms the beginning of the renal tubule
Bowman’s capsule
TRUE OR FALSE
Glomerular filtration barriers are SELECTIVE filter
False; it is non-selective
What are the three glomerular filtration barriers?
1) Capillary wall membrane
2) Basement membrane
3) Visceral epithelium of Bowman’s capsule
In the glomerulus, this are foot like processes that has _____________ that repels negative charged protein
PODOCYTES; Shield of negativity
Specific gravity of plasma filtrate
1.010
Factors influencing glomerular filtration
a) Structure of capillary walls and Bowman’s capsule
b) Hydrostatic and oncotic pressure
c) Feedback mechanism of RAAS (Renin-Angiotensin-Aldosterone System)
Explain the RAAS; how does it work?
Low Na+ –> Decrease H2O retention –> Decrease Blood volume –> Decrease BP –> Macula densa sense changes in BP
–> Juxtaglomerular cells produce and secrete RENIN (enzyme and Hormone) -> Renin + Angiotensinogen –>
Angiotensin I + Angiotensin converting enzyme (In the alveoli of the lungs) –> Angiotensin II, which will:
Angiotensin 2 will
- Dilate afferent arteriole and constrict efferent arteriole
- Triggers the release of ALDOSTERONE and ADH (Antidiuretic hormone).
What is the role of aldosterone and ADH in RAAS?
ALDOSTERONE - For retention/reabsorption of sodium
ADH - Retention of water
GFR: <15 mL/min
what is the stage and description that is according to the systematic classification of chronic kidney disease?
Stage 5; kidney failure
Proximal convoluted tubules has columnar cells with ____________ border
Brush border
PCT reabsorbs ….
Bicarbonate
Urea
Uric acid
Water
Glucose
Salt
Calcium
Phosphate
Protein
This mechanism uses ATP, movement of substance against a gradient
active transport
In active transport, where does Na+ is reabsorbed?
PCT & DCT
In active transport, give the other substances and their location where they are reabsorbed
Glucose, amino acid, NaCl - PCT
Chloride - ascending loop of Henle
Movement of substance as a result of differences in concentration
passive transport
TRUE OR FALSE
H2O is reabsorbed in all parts except descending loop of Henle
FALSE
it should be ascending loop of Henle
What is the glucose renal threshold and its average?
160-180 mg/dL
ave: 170 mg/dL
Give the sodium threshold
120 mmol/L
Give the threshold substances
NaCl
amino acids
creatine
ascorbic acid
Tubular concentration begins in the
descending and ascending loop of Henle
Maintains the osmotic gradient of the medulla
Countercurrent mechanism
Distal convoluted tubule secretes this substance to make the urine acid
NH3 Ammonia
This is where the final adjustment of the urinary composition
Distal convoluted tubule
It regulates the final urine concentration by controlling tubular permeability
Antidiuretic hormone/ADH
Explain what happens when there is LOW and HIGH BODY HYDRATION
Low body hydration –> Present ADH - CD is permeable to water –> low urine volume (Oliguria)
High body hydration –> Absent ADH - CD is impermeable to water –> high urine volume (Polyuria)
Factors that suppresses Antidiuretic hormone
Caffeine
Alcohol
Diuretics
In nephrogenic diabetes insipidus, there is
There is ADH resistance
In neurogenic diabetes insipidus, there is
There is LOW ADH
