Module 9: KUB, RBF, Tubules, Hormones And Renal Function Tests (a) Flashcards
1
Q
Renal system Overview
-Primary Functions
A
- Maintain stable internal environment for optimal cell tissue metabolism — Ex Blood pressure*
- Balance solute and water transport
- Excrete metabolic waste products
- Conserve nutrients
- Regulate serum pH
2
Q
Renal system Overview
-Endocrine Functions?
A
- Renin — Important for regulation of BP
- Erythropoietin — Production of erythrocytes in response to low oxygenation
- 1,25-dihydroxyvitamin D3 — important in metabolism of calcium — performs gluconeogenesis in renal cortex
- Forms urine
3
Q
Nephron
-Info
A
- Functional unit of the kidney
- Superficial cortical nephrons — 85% of all nephrons — located on outer edge
- Midcortical nephrons
- Juxtamedullary nephrons — Concentrate urine and secrete renin - EACH kidney contains 1.2 million nephrons
4
Q
Glomerulus
-Info
A
- Afferent arteriole — Supplies glomerulus w/ blood
- Efferent arteriole — Returns blood to systemic blood flow — Away from glomerulus
- Juxtaglomerular apparatus **
- Controls renal blood flow, glomerular filtration, and renin secretion
5
Q
Glomerulus
-Juxtaglomerular Apparatus
A
- Control renal blood flow, glomerular filtration, and renin secretion
- Juxtaglomerular cells — Specialized cells located around afferent arterioles
- Macula densa — Specialized sodium and chloride sensing cells — Found in distal convoluted tubules where afferent and efferent arterioles enter glomerular space
6
Q
Glomerulus & Juxtaglomerular Apparatus
-Function
A
- Juxtaglomerular cells — Surround afferent arteriole — Distal tubule and afferent arteriole come into contact
- Macula Dens — Line the Distal tubule — Measure sodium concentration of urine being excreted — Regulates sodium concentration
- Glomerulus — Tuft of capillaries surrounded by Bowman’s capsule —
—Space between glomerulus and Bowman’s capsule is the Bowmans Space — Filtrate (Mostly water) is in this space
—Filtrate in Bowman’s space should NEVER contain PROTEIN when kidney is healthy
7
Q
Glomerulus
-3 layers?
A
- Endothelial cell layer — forms lumen and comes into contact with blood — contains pores that allow for particles to pass through
- Basement Membrane — Selectively permeable & NEGATIVELY charged (Repels negatively charged material) Ex of Neg charged is: ALBUMIN
—Damage to Basement membrane removes Negative charge — Allows proteinuria and hematuria** - Visceral Capillary Epithelium — Contains foot processes of podocytes — Interlocking fingers serve as filtration slits
8
Q
Bladder
-Components
A
- Detrusor muscle — “basket weave” of smooth muscle — muscle fibers run in different directions to cause bladder to contract
- Trigone — Smooth triangular region where 2 ureters and urethra sit
- Transitional epithelium — Allows bladder to expand and contract — Provides interface between urinary space and underlying vasculature
9
Q
Urethra
-Components
A
- Internal sphincters — autonomic regulation; parasympathetic fibers— smooth muscle located at junction of bladder & Urethra
- External sphincter — Voluntary control — striated skeletal muscle — Skeletal motor neurons in pudendal nerve (L4 -S3)
- Female Urethra — 3 to 4 cm long — Increased UTI’s in female
- Male urethra — 18 to 20 cm long
10
Q
Renal Blood Flow
-Process
A
- Kidneys receive 1000 to 2000 ml/min of blood
- GFR
- Filtration of plasma into bowman space
- 120 to 140 ml of plasma per minute
- DIRECTLY related to perfusion pressure in the glomerular capillaries** - If MAP decreases or renal artery vascular resistance increases, renal blood flow decreases*
11
Q
Glomerular Filtration
-Process
A
- Glomerulus is freely permeable to water and relatively impermeable to large colloids such as plasma proteins
- Size and electrical charge are important factors that affect permeability
—Positive-charged particles permeate the membrane more readily than neutral or Negative-charged particles**
12
Q
Glomerular Filtration
-Net Filtration Pressure**
A
- Combined effect of forces favoring and forces opposing filtration
- Favoring Forces — Capillary hydrostatic pressure
- Opposing Forces — Oncotic pressure in the capillary AND hydrostatic pressure in Bowman capsule
- Glomerular Filtration Results in — NET POSITIVE FILTRATION 10mmHg leaving glomerulus into proximal convoluted tubule
13
Q
Renal Blood Flow Regulation Systems
-3 Methods
A
- Auto regulation
- Myogenic mechanism
- Tubuloglomerular feedback - Neural Regulation
- Hormonal Regulation
- RAAS
- Natruiretic Peptides
14
Q
Renal Blood Flow Regulation & GFR
-Auto-Regulation
A
- Goal is to maintain constant GFR when atrial pressure is between 80 to 180mmHg
- As SBP increases, afferent arterioles constrict preventing an increase in filtration pressure**
—Also prevents wide fluctuations in the systemic arterial pressure from being transmitted to glomerular capillaries
15
Q
Renal Blood Flow Regulation
-Auto-regulation — Myogenic Mechanism (Stretch)
A
- As atrial pressure declines, stretch on the afferent arteriolar smooth muscle decreases
—Afferent arteriole relaxes and glomerular perfusion INCREASES
16
Q
Renal Blood Flow Regulation
-Auto-Regulation Tubuloglomerular Feedback
A
- When sodium filtration increases (As sensed by the macula densa*), GFR needs to be decreased
- Macula densa cells stimulate afferent arteriolar VASOCONSTRICTION