Urinary Tract Flashcards
what are the 6 homeostatic roles of the kidney?
- regulation of extracellular fluid volume
- Regulation of blood osmolarity
- Maintenance of electrolyte balance
- Regulation of blood pH
- excretion of waste
- hormone production
The homeostatic roles are achieved in 3 main events conducted in the nephrons.. which are?
- Glomerular filtration
- Tubular reabsorption
- Tubular secretion
What does glomerular filtration do?
removes solutes from the blood
- receives 12-30% of cardiac output
What happens in the glomerulus?
filtration of solutes from the blood
What covers the glomerulus?
Bowman’s capsule
What happens to the osmolarity as you descend into the renal medulla?
it increases
What happens at the proximal convoluted tubule?
Reabsorption of ions, water, and nutrients into the blood
removal of toxins and adjustment of filtrate pH
What is the proximal convoluted tubule lined with?
Simple cuboidal brush border epithelium
What proportion/% of nutrients/water/electrolytes are reabsorbed in the PCT?
nearly all of the essential nutrients and 70-80% of
electrolytes and water are reabsorbed
How does the PCT help to maintain the pH and ionic balance of body fluids?
by selective secretion of hydrogen ions, ammonia, and K+ into the filtrate and absorption of HCO3
What happens in the descending loop of Henle? What does this require
Aquaporins allow water to pass from the filtrate into the interstitial fluid
- concentrate the filtrate
- requires energy
What happens in the ascending loop of Henle?
Reabsorption of Na and CL from the filtrate into the interstitial fluid
- active or passive
What is the main role of the loop of Henle as a whole? (2 things actually)
to maintain high osmolarity of the interstitial fluid
production of concentrated urine
What happens to the filtrate as it passes up through the ascending loop of Henle?
it gets diluted due to the passage of electrolytes to the medullary fluid
What is the lining of the distal tubule like?
lined with simple cuboidal cells that lack a brush border
What happens in the distal tubule?
selective secretion and absorption of various ions in maintain blood pH and electrolyte balance
- Ca2+, K+, Na+
What does the collecting duct connect?
the nephron to the ureter
What happens in the collecting duct? (secretion/resorption)
The secretion of K+ and the resorption of Na+
What hormones regulate the collecting duct?
vasopressin and aldosterone
What are 4 hormones that are made in the kidney?
- Calcitriol
- Klotho
- Renin
- EPO
What cells in the kidney make calcitrol?
proximal tubular cells (PT)
What cells in the kidney make klotho?
distal tubular cells (DT)
What cells in the kidney produce renin? where ?
Juxtaglomerular epithelioid cells in the media layer of afferent arterioles
located at the entrance of the glomerulus
What cells synthesize EPO?
interstitial fibroblast-like cells located between proximal tubules
What is calcitriol? what is the main role?
Physiologically active form of vitamin D
Contributes to bone mineralization by regulating homeostasis of Ca2+ and phosphate
What does calcitriol inhibit? what other functions does it have?
Inhibits renin expression
Also affects erythropoiesis and leukocyte activity
What are the layers of the uerter? (inside to outside)
- Transitional epithelium
- Lamina propria
- Muscularis
- Adventitia
What allows for expansion of the ureter?
Folding of the lamina propria and lumen
What are the layers of the muscularis like in the ureter?
opposite from the GI tract
- inner longitudinal, middle circular, and outer longitudinal
What kind of movement is the ureter capable of
peristaltic waves
Filling of the bladder compresses…
the oblique openings to the ureters
What allows for expansion of the urinary bladder?
Rugae
What is the capacity of the urinary bladder like?
300-500 mL
What is the transition of epithelium like in the female urethra? Where does this occur?
Epithelium of the female urethra changes from transitional at the bladder to non-keratinizing stratified squamous distally
What is the change of epithelium like in the male urethra ?
changes to pseudostratified through prostatic, membranous and most of the penile uretha, then to non-keratinizing stratified squamous distally
What are some common diseases of the kidney?
- Cancer: renal carcinoma (tubule cells)
- Polycystic kidney diseases
- Systemic lupus erythemoatosus which leads to lupus nephritis
- Chronic kidney disease due to things like diabetes and HPB
- Kidney and uretal stones
When do kidney and uretal stones develop?
Develop in the kidneys when there are crystal in the urine and small particles surround and collect on them
Circulating ___ may cause glomerular disease
immune complexes
Many glomerular diseases are mediated by ..
antigen antibody immune complexes
What type of hypersensitivity reactions are often involving complement activation?
type III
What property of immune complexes determines the site of glomerular disease?
size
• small complexes move through the BM
•larger complexes get stuck in the mesangium or subendothelial
What happens to immune complexes that deposit in the glomeruli?
activate complement and cause cellular damage
split complement products attract macrophages and neutrophils which cause further damage
What are some common diseases of the urinary tract/bladder?
- Benign Prostatic hyperplasia
- Urinary incontinence
- Cancer: of tubule cells or renal cell carcinoma
- Bladder prolapse
- Hematuria
- Interstitial cystitis
- Nephritic Syndrome
- Urinary Tract Infection
What is benign prostatic hyperplasia?
Enlargement of the prostate which causes pressure on the urethra
What is nephrotic syndrome? What are 3 symptoms
Injury (from multiple causes) to the glomeruli results in…
- high levels of protein in the urine
- low levels of albumin in the blood
- leakage of fluid out of peripheral blood vessels = ankle swelling
What kinds of diseases will NOT cause nephrotic syndrome?
diseases that affect tubules and interstitium
What are 4 symptoms of Nephritic syndrome?
- Blood in the urine
- High BP
- Decreased GFR
- More inflammation than in nephrotic syndrome
UTIs are defined by…
presence of microorganisms in the urinary tract
What are 4 main non immune innate defences protecting against UTIs?
- Urine flow
- Batericidal factors in urine
- Sloughing of infected epithelial cells
- Tamm Horsfall protein
What reflex is a major host determinant in the localization and severity of UTIs
Vesicoureteric reflux (urine backing into the kidneys)
What does Tamm Horsfall Protein do? where is it made?
Made in the kidney
prevents attachment of fimbriated E. coli to epithelial cells
What kind of Ig response is there to bacterial UTIs?
IgA
