urinary Flashcards
cats kidney
-true unipyramidal before and after birth
-can be yellow if cat is obese and is normal
-FIP leads to vasculitis which is white lesions following vasculature. if not following than could be neoplasia
Horse kidney
-left normal, right heart shaped.
-urine has lots of calcium carbonate cloudy pee is normal
major components of the kidney
-if you damage one the others will follow, damaged glomeruli leads to damaged tubules. -vessels, glomeruli, tubules, interstitum.
-kidney looks the same in chronic stages of the disease
vascular supply to the kidney
-20-25% cardiac output
-helps maintain BP
-supplied by end arterioles
-supplied by renal artery
Regulation of renal blood flow
Juxtaglomerular apparatus
1. Juxta glomerular cells (afferent arteriole)
2. Efferent arteriole
3. Macula densa (distal convoluted tubule)
4. Mesangial cells
what and how kidneys respond to changes in BP
Respond to:
1. Depletion of extracellular fluid–> ADH release
2. Decrease in renal blood pressure–> ang-II
3. Decrease in sodium chloride-> Aldosterone
glomerulus
Function: production of the ultrafiltrate
Structure:
- Capillaries
- Mesangial cells
- Podocytes
Glomerular Filtration Barrier
- Composed of
1. Fenestrated endothelium
2. Glomerular basement membrane
3. Podocytes
-selective permeability based on size, charge, and capillary pressure
tubules
_Proximal convoluted tubules:
* Reabsorb water, solutes
(Na, Cl, HCO3), glucose,
amino acids
* Excrete hydrogen.
* PT have large number of mitochondia since they need lots of energy.
-first structure to encounter toxins ect. will get necrosis first. decreased renal BP can cause death of tubule cells.
loop of henle
- Creats a corticopapillary
osmolarity gradient**
-the one structure responsible for water conservation/ reabsorption. - Establishes hypertonicity
within the medullary interstitium - Descending loop is
permeable to water only
(water goes out) - Ascending loop is
permeable to solutes only
(solutes go out)
how is urine concentrated?
- Two requirements for urine concentration:
1. Cortico-papillary osmolarity gradient
(within the interstitium) created by countercurrent multiplier (loop of henle) and urea recycling in the renal medulla.
2. Presence of ADH
Collecting duct
- Permeable to small amount of water but not urea (except at its distal end)
- Susceptible to ADH which causes the collecting tubules to become more permeable to water
- ADH increases water reabsorption from 4%-24%
Interstitium:
- Contain peritubular capillaries and fibroblasts
- Expansion is abnormal and may occur due to
edema, infiltrate or fibrosis
examining capsule of kidney
- should be able to remove easily, if you are unable to it means there is renal fibrosis. Capsule is stuck to the kidney.
-ex. horses can be hard to peel
Functions of the kidney
- Formation of urine elimination of waste and conservation of water
- Acid-base regulation
- Maintenance of electrolyte balance
- Endocrine function:
– Renin-angiotensin system (hypertension with renal failure)
– Erythropoietin (rbc formation) can get anemia with renal failure
– Vitamin D
Kidney function requirements
- Adequate blood flow
- Functioning nephrons
- Excretion of urine
Azotemia
-Increased concentration of non-
protein nitrogenous wastes (urea and creatinine) in the BLOOD
3 causes:
1. Pre-renal azotemia
2. Renal azotemia
3. Post-renal (obstruction)
azotemia and renal failure
-azotemia in blood and low USG in urine means renal failure.
-you can have azotemia and no renal failure.
Renal failure, 3 types and causes
-Impaired renal function associated with azotemia
* 75-80% of the renal function is lost
Pre renal causes: Shock, hemorrhage, heart failure, severe
dehydration, DIC. related to blood.
- Renal causes: damage to tubules or glomeruli by a long list of
industrial or natural (plant) toxins and metals, acute
glomerulonephritis, renal infection. related to renal disease. - Post renal causes: Obstruction within the lower urinary tract.
- Can be acute or chronic
- Can be reversible
uremia
-The syndrome associated with
multisystemic lesions and clinical signs because of renal failure.
-animal with uremia will have azotemia.
- Clinical syndrome of renal failure
- Can be seen with acute and chronic renal failure (more in chronic).
- Results in gross lesions within other organs via one of two mechanisms: ***
1. Vascular endothelial injury
2. Alteration in Ca/P balance
End Stage Renal Disease or Kidney disease
- Renal function is less than 5% of normal
- Animal is in the terminal stages of uremia
acute renal failure
- Acute and sudden reduction in renal function that result in
azotemia - Cause is severe damage to kidney components from pre-renal,
renal or post renal causes - BUN and creatinine are both high and urine specific gravity is low
- Reduced blood pH (metabolic acidosis)
- Alterations in plasma ion concentrations, particularly hyperkalemia, calcium, and phosphate
-hyperkalemia effects heart and can kill animal - Can be reversible
Chronic Renal Failure
- Similar to acute BUT longer duration and irreversible
- Most common renal disorder in dogs and cats
- Usually progressive loss of renal function
- Usually high blood phosphate and low calcium and normal to low potassium
-diffusly fibrotic kidneys, white, shrunken. could have areas of uremia.
How uremia produces gross lesions following vascular injury
-Vascular injury causes one or more of the following:
1 . Thrombosis, ischemia, necrosis and hemorrhage
2. Increased vascular permeability (edema)
3. leakage of urea and its conversion to caustic ammonia by bacteria leading to ulceration
How uremia produce gross lesions
Alteration in Ca/P balance.
Low Ca and high P
- Chronic renal failure causes low Ca and high P due to decreased GFR
- Chronic renal failure causes decreased Vit. D production leading to decreased gut absorption of Ca.
Consequences of low Ca and high P:
- Parathyroid hyperplasia and increased parathyroid hormone. bilateral usually renal failure, one usually thyroid.
- Fibrous osteodystrophy (release of Ca from bone and with time Ca is
replaced by fibrous tissue)
- Widespread mineralisation***
where to exam gross if you have renal failure
-bilateral parathyroid hyperplasia
-oral cavity (tongue tip necrsis or ulcerative glossitis)
-stomach: uremic glossitis, in small animals, uremic colitis in large animals.
-bones (grab rib bone is it bends there is fibrous osteodystrophy)
Renal Dysplasia
- Renal dysplasia is disorganized development of renal parenchyma due to anomalous differentiation
- Congenital
- Young animals present with renal failure
- Cause:
Unknown (viral, random hereditary abnormality)
Progressive Juvenile Nephropathy
- A form of renal dysplasia?
- Also known as familial (hereditary) renal disease
- Young dog disease
- Runs in families of dogs and in specific dog breeds
- Hereditary
-white fibrotic misshaped kidney
renal cysts
- Dilated nephron structure filled
with water fluid - Acquired: secondary to fibrosis squeezing tubules.
- Congenital
Polycystic Kidney Disease
- Inherited as an autosomal
dominant trait in families of Persian
cats and bull terriers and
others….. - Can lead to renal failure