Lesson 1: Renal Anatomy & Physiology and Function Test Flashcards
The human body contains approximately how many nephrons per kidney?
1 to 1.5 million
This is located adjacent to the ascending and descending loops of Henle in juxtamedullary nephrons and in this area, the major exchanges of water and salts take place between the “Blood” and the “Medullary Interstitium”
Vasa recta
2 Types of Nephrons
Cortical Nephrons:
- 85% of nephrons
- Cortex
- Removal of waste products and reabsorption of nutrients
Juxtamedullary nephrons
- Have longer loops of Henle
- Medulla
- For concentration of urine
This supplies blood to the kidney
Renal artery
What percentage of blood do human kidneys receive from the heart?
25%
Blood enters the capillaries of the nephron through the?
Afferent arteriole
Before returning to the renal vein, blood from the efferent arterioles enters the _________ and _________ and flows slowly through the cortex and medulla of the kidney close to the tubes
peritubular capillaries and vasa recta
These surround the proximal and distal convoluted tubules, providing for the:
Proximal convoluted tubule = immediate reabsorption of essential substances from the fluid
Distal convoluted tubule = final adjustment of urinary composition
Identify the capillaries
Peritubular capillaries
Based on the average body size of 1.73m^2, what is the:
Total Renal Blood Flow:
Total Renal Plasma Flow:
Total RBF: 1200 mL/min
Total RPF: 600-700 mL/min
Normal value fors renal blood flow and renal function tests depend on?
Body size
The glomerulus consists of a coil of approximately ____________
8 capillary lobes
The walls of the capillary lobes are referred to as?
Glomerular Filtration Barrier
The glomerulus is located within ___________, which forms the beginning of the renal tubule
Bowman’s capsule
The pores increase capillary permeability but do not allow the passage of large molecules and blood cells, these are referred to as?
Fenestrated endothelium
Plasma filtrate must pass through 3 Glomerular Filtration Barrier Cellular Layers which are?
Capillary Wall Membrane
Basement Membrane (Basal Lamina)
Visceral Epithelium of Bowman’s Capsule
Which serves as a “non-selective filter” of plasma substances? MW: <70,000
Glomerulus
Further restriction of large molecules occurs as the filtrate passes through the basement membrane and the thin membranes covering the filtration slits formed by the intertwining foot processes of the _________ of the INNER LAYER of the Bowman’s capsule
Podocytes
The primary protein associated with renal disease
Albumin
Renal Blood Flow (7)(RAGE PVR)
Renal artery
Afferent arteriole
Glomerulus
Efferent arteriole
Peritubular capillaries
Vasa recta
Renal vein
What monitors the blood pressure and plasma sodium content?
Juxtaglomerular apparatus which consists:
JG Cells = afferent arteriole
Macula densa = DCT
An autoregulatory mechanism within the juxtaglomerular apparatus maintains the glomerular blood pressure at a relatively constant rate, regardless of fluctuations in systemic blood pressure by what action?
By changing the size of the afferent and efferent arterioles
When blood pressure drops, this action prevents a marked decrease in blood flowing through the kidney, thus preventing an increase in the blood level of toxic waste products.
Afferent arterioles:
Efferent arterioles:
Drop in BP
Afferent: Dilation
Efferent: Constriction
This system regulates the blood flow to and within the glomerulus
RAAS
If not for the ___________, all routine urines would have positive readings on reagent strips for protein and albumin
Shield of negativity
When blood pressure increases, what action takes place between the afferent arterioles and efferent arterioles?
Increase in BP
Afferent: Constriction
Efferent: Dilation
Renin is produced by what cells?
Juxtaglomerular cells
Urinary Filtrate Flow (10) (BPDAD CRUBU)
Bowman capsule
Proximal CT
Descending LH
Ascending LH
Distal CT
Collecting duct
Renal calyces
Ureter
Bladder
Urethra
Angiotensin II corrects renal blood flow by? (3)
Causing vasodilation of afferent arterioles and constriction of efferent arterioles
Reabsorption of Sodium and Water in the PCT
Release of Aldosterone (sodium-retaining hormone from Adrenal cortex) and ADH (from the Hypothalamus)
Every minute, approximately 2-3 million glomeruli filter how much water-containing LMW substances?
120 mL
What is the specific gravity of the ultrafiltrate of plasma as it leaves the glomerulus?
1.010
The cellular mechanisms involved in tubular reabsorption are termed as?
Active and passive transport
Active Transport is responsible for the reabsorption of these substances in?
Glucose, amino acids, and Salts =
Chloride =
Sodium =
Glucose, AA, Salts = PCT
Chloride = Ascending LH
Sodium = DCT and PCT
Which part of the nephron is water unable to cross because its walls are impermeable to water?
Ascending Loop of Henle
Passive Transport is responsible for the reabsorption of these substances in?
Water =
Urea =
Sodium =
Water = PCT, DCT, Descending LH except for Ascending LH
Urea = PCT, Ascending LH
Sodium = Ascending LH
When plasma concentration of a substance that is normally completely reabsorbed reaches a level that is ABNORMALLY HIGH, the filtrate concentration exceeds the _____________ of the tubules, and the substance begins appearing in the urine
Maximal reabsorptive capacity (Tm)
Plasma renal threshold of GLUCOSE
160 to 180 mg/dL
The plasma concentration at which active transport stops is termed as?
Renal threshold
Tubular secretion serves two major functions (2)
Eliminating waste products not filtered by the glomerulus
Regulating acid-base balance through H+ secretion
Why can’t medications be filtered by the glomerulus?
They are bound to plasma proteins
This selective reabsorption process serves to maintain the osmotic gradient of the medulla
Countercurrent mechanism
Major site of removal of nonfiltered substances is in the?
Proximal convoluted tubule
The buffering capacity of the blood depends on what ions that are readily filtered by the glomerulus and must be returned to the blood expediently to maintain proper pH
Bicarbonate ions (HCO3-)