T1: Renal Function (Part 1) Flashcards
4 components of the urinary system
- kidney
- Ureter
- bladder
- urethra
Anatomy of the kidney
- Vascular supply
Efferent arteriole - outgoing blood
Afferent arteriole - incoming blood
Peritubular capillaries
Vasa Recta
Location of the medulla
Loops of Henle and collecting ducts
Location of the cortex
Where glomeruli are on outside edge
Location of the calices
Where the collecting ducts dump
Location of the renal pelvis
Trunk that will empty into the ureter
Order of the nephron in order
Afferent arteriol, efferent arteriol, blood filtered at Glomerulus, Proximal Convoluted Tubules, Loops of Henle, Distal Convoluted Tubules, Collecting Ducts
Juxtaglomerular apparatus (JGA) - function
Regulated the function of each nephron
Juxtaglomerular apparatus (JGA) - Importance of location
Found between the vascular pole of the glomerulus and the returning distal convoluted tubule of the same nephron.
Importance: location is critical to its function in regulating renal blood flow and the glomerular filtration rate
Juxtaglomerular apparatus (JGA) - functions of granular cells
secrete renin, which is an enzyme that is the starting point for the renin-angiotensin-aldosterone system
Juxtaglomerular apparatus (JGA) - functions of macula densa cells
Regulate sodium and chloride concentrations by sensing (NaCl) in the DCT.
Juxtaglomerular apparatus (JGA) - functions and mesangial cells
Receive stimulation from sympathetic nervous system to modulate actions of the JGA
Three functions of the kidney
- excretion
- homeostatic regulation
- endocrine
Three basic procedures involved in renal excretion
Filtration, reabsorption, and secretion
In FILTRATION, are substances being conserved in the blood or are they excreted in the urine
Going into forming urine from blood
In REABSORPTION, are substances being conserved in the blood or are they excreted in the urine
Capillary system taking substance into the blood
In SECRETION, are substances being conserved in the blood or are they excreted in the urine
From blood to secretion
What two plasma constituents that are not normally filtered through the glomerulus?
- high molecular weight plasma proteins
- cells
Definition of Glomerular Filtration Rate (GFR)
rate in milliliters per minute that that substances are filtered through the kidney’s glomeruli
Normal GFR
125-130 mL/min
Two clinical uses of GFR measurement
- measure of number of functioning nephrons
- sensitive and specific marker of changes in overall renal function
Three forces which determine glomerular filtration pressure
Hydrostatic pressure of blood Fluid pressure (Glomerular hydrostatic pressure) Plasma osmotic pressure (colloid)
Ten substances reabsorbed in the proximal convoluted tubule
- Na+
- HCO3-
- Glucose
- amino acids
- proteins
- phosphate
- sulfate
- Mg2+
- Ca2+
- uric acid
specific renal threshold for glucose
about 160 mg/dl
Major purpose of the countercurrent mechanism
Purpose is to remove water from the filtrate on the way down the descending loop making it very salty at the bottom of the loop. Then, on the way up the ascending loop, active reabsorption of sodium and chloride ions occurs. OR like a water heater, allows for the reabsorption of H2O, Na, Cl, and urea with less energy expenditure
Where does the countercurrent mechanism occurs in the nephron
Loops of Henle
differentiation of the histology of the descending and ascending limbs
Descending: permeable to water so there is passive water and urea reabsorption
Ascending: impermeable to water so there is active reabsorption of sodium and chloride
Coutercurrent mechanism
- movement of SODIUM in or out of the renal tubules
Out
Coutercurrent mechanism
- movement of CHLORIDE in or out of the renal tubules
Out
Coutercurrent mechanism
- movement of UREA in or out of the renal tubules
In
Coutercurrent mechanism
- movement of WATER in or out of the renal tubules
Out
Two distinct regulatory functions of the distal convoluted tubule
Responsible for acid-base, water and electrolyte balance control in the nephron so…
- sodium reabsorption
- potassium secretion
Four substances that are normally reabsorbed in the distal convoluted tubule
Reabsorption of sodium, chloride, bicarbonate, and water
Four substances that are normally secreted in the distal convoluted tubule
Secretion of K+, H+, NH4+, and uric acid
Specific hormone that exerts its effect on the distal convoluted tubule
Aldosterone
What substances are normally reabsorbed in the collecting ducts
increased or decreased water adsorption is controlled here
What hormone exerts its effect on the collecting ducts
Antidiuretic hormone (ADH) (Vasopressin)
- presence causes water reabsorption by widening pores
- absence causes decrease water reabsorption
Net movement of substance against a concentration or electrical gradient; requires energy expenditure
Active tubular absorption
substance moves by simple diffusion as a result of a concentration or electrical gradient; no energy expenditure
Passive tubular absorption
