Week6: Chapter 13: The urinary tract Flashcards
The formation of urine is accomplished in the
nephron- basic funcional unit of each kidney
Secretory functions of the kidney
Secretes renin
secretes erythropoietin
Diagram of the kidney
Facts for understanding the kidney:
primary function
- ) Primary funtion of the kidney is to excrete urine.
- The kidneys must be anatomically normal
- body must have sufficient blood flow and adequate hydration
- hormones also regulate renal function: antidiuretic hormone (ADH) from the posterior pituitary, and atrial natriuretic hormone from the atria of the heart, Aldosterone from adrenal cortex
- passages must be patent to excrete urine
Renal failure classifications
- pre-renal: shock
- Renal: kidney diseases
- post-renal: obstruction
Facts to know about the kideny:
-infection
The urinary tract is extremely sensitive to bacterial infections.
The kidneys are perfused constantly by a high volume of blood, which is filtered in the glomeruli.
Bacteria found in the circulation thus have a good chance of entering and colonizing the kidneys and causing a urinary tract infection (UTI).
Moreover, because the ure-thral opening lies external to the body, bacteria may easily enter the urinary tract through it as well.
UTIs that are acquired from bacteremia are called descendingor hematogenous infections, whereas those attributable to upstream bacterial spread are called ascending infections
Facts to know about the kidney:
Glomeruli and infection
The specialized capillaries of the glomeruli are a ready target for bloodborne antibodies.
The glomeruli filter large amounts of blood.
During this process, their basement membranes are exposed to potentially noxious plasma components—most notably, antibodies and antigen-antibody complexes.
Glomeruli are thus often involved in many systemic autoimmune diseases mediated by antibodies. Antibody-mediated disease of the glom-eruli is known as glomerulonephritis and may be acute or chronic”
Facts to know about the kidney:
Renal tubules
Renal tubules are composed of highly specialized cells that are very sensitive to a lack of oxygen and to the adverse action of toxins.
Because the proximal tubular cells have the most complex function of all parts of the nephron, and require the most oxygen, they are most suscep-tible to hypoxia or anoxia.
Even a short interruption of blood supply or a hypoperfusion of the kidneys, as typically occurs in shock or heart failure, results in tubular necrosis.
Many drugs, poisons, heavy metals, and endogenous waste products that are filtered through the glomeruli are taken up by the proximal tubular cells and may adversely affect them.
For example, mercury salts inactivate the enzymes of the proximal tubules and, if ingested in large amounts (e.g., in suicidal mercury poisoning), can cause necrosis of the proximal tubules.”
Facts to know about the kideny: carcinogens
The urinary tract is exposed to many carcinogens that are excreted in urine
ex. bladder cancer r/t carginogens of tobacco smoke excreted in urine
Facts to know about the kidney: presentation of diseases
May present with local or systemic symtpoms
-a variety of symptoms that may be either localized to the urinary tract or systemic, affecting the entire body.
The best-known local symptom is the flank pain that occurs with kidney infection (pyelonephritis) or renal tumors.
Painful urination (dysuria) is the best-known symptom of cystitis.
Urinary colic is a symptom associ-ated with urinary stones impacted in the ureters.
Colic attacks of spasmodic pain occur as the ureteral smooth muscles contract in an effort to propel the stone and relieve the urinary obstruction”
Polyuria, oliguria, anuria
polyuria: overproduction of urine
oliguria: low urine output
anuria: no urine output
pyuria: pus in urine (leukocytes, appears turbid)
Bacteremia: numerious bacteria in urine
What is uremia?
Characterized by
“poisoning with urine”
Characterized by retention of water; minerals (e.g., sodium, potassium, chloride, calcium, and phosphate); organic substances, such as creatinine or uric acid; and other nitrogen-rich substances, such as ammonia, measured in the clinical laboratory as blood urea nitrogen (BUN).
Hypercalcemia or hyperkalemia endanger life, because these metabolic changes may cause cardiac arrest
Chronic uremia?
Marked by
Chronic uremia is marked by profound neurologic changes and depression of the central nervous system, which initially presents as somnolence and fatigue and ultimately results in coma and death.
Fortunately, by an act of Con-gress introduced in the 1970s, all Americans are entitled to free treatment of chronic renal failure; therefore, end stage chronic renal disease (uremia) is a rare cause of death in the US. Clinically, renal failure is encountered usually only in patients who have many other severe diseases or suffer from decompensated untreatable multiple organ failure.”
Polycystic kidney disease
- autosomal dominant
- r/t mutatin for gene coding polycystin-1, a cell-to-cell adhesion molecule that holds cells together
- cysts, increase weight 20x normal, 3000-4000g
cysts are from obstructed tutbules and contain fluid
resons for obstruction is unknown, but renal function is gradually impaired.
renal failure by 40-50 yo
Glomurulopathies: table
Catagories of glomerulopathys
Immunologic: glomerulonephritis
Metabolic: diabetes, amyloidosis
Circulatory: HTN, atherosclerosis, disseminated intravascular coagulation
Glomerular Disease: Immunologic
immunologic injury is most often mediated by antibodies and can be classified as a type II (cytotoxic) or type III (immune complex) hypersensitivity reaction.
Pathologic studies reveal that such injury is marked by deposits of immunoglobulins in the glomeruli.
If the deposition of immunoglobulins on GBM evokes an inflammatory reaction, the disease is classified as glomerulonephritis.
Those glomerulopathies that have an immunologic patho-genesis or a presumptive immunologic pathogenesis but that do not show signs of inflammation carry names without the suffix -itis (which is reserved for inflammatory disease). Within this category, the most important diseases are lipoid nephrosis, membranous nephropathy, and immunoglobulin A (IgA) nephropathy.
Immune-mediated glomerulonephritis can occur in an isolated form (primary) or in the course of a systemic disease (secondary), as in systemic lupus erythematosus (SLE) or granulo-matosis with polyangiitis. Primary glomerulonephritis is often limited to the glomeruli, whereas secondary glomerulone-phritis is usually associated with tubulointerstitial renal inflammation.”
metabolic glomerular disorders
best example is DM
Diabetes causes biochemical changes in the composition of the GBMs, which become thickened and “leaky” as a result of a loss in their selective semiperme-ability.
Diabetic glomerulosclerosis, like other metabolic glomerulopathies, is also associated with pathologic changes involving other parts of the kidney, including arterioles, renal tubules, and interstitial spaces”
Cirulatory disturbances of the glomeruli
- Atherosclerosis of the renal arteries is typically associated with hypoperfusion, which leads to involution and hyalin-ization of glomeruli.
- The sudden onset of hypertension may cause fibrinoid necrosis of the glomerular capillaries.
Shock is often associated with disseminated intravascular coagula-tion (DIC) and the formation of microthrombi in the glo-merular capillaries.
Syndromes of glomerular diseases
Rapidly progressive glomerulonephritis: is characterized by a loss of renal excretory function over a period of several weeks. The destruction of glomeruli presents initially with hematuria, progressing fast to oliguria, and finally to anuria. Acute renal failure is typically caused by crescentic glomerulonephritis.
- Nephritic syndrome: is diagnosed on the basis of typical clinical and laboratory findings. These include generalized edema, hypertension, hematuria, protein-uria, and hypoalbuminemia. Acute nephritis syn-drome is usually caused by acute poststreptococcal or postinfectious glomerulonephritis. The most common cause of chronic nephritic syndrome is systemic lupus erythematosus.
- Nephrotic syndrome is characterized by general-ized edema, proteinuria, hypoalbuminemia, and often hyperlipidemia and lipiduria. The most common causes of nephrotic syndrome in adults are focal glo-merulosclerosis, membranous nephropathy, and diabetes. Lipoid nephrosis is the most common cause of nephrotic syn-drome in children.
- Isolated glomerular hematuria, with or without proteinuria, is usually not accompanied by constant clinical symptoms and generally can be diagnosed only on the basis of abnormal urinary findings. This syndrome, as typically seen in IgA nephropathy (Berger’s disease), may progress to chronic renal failure like any other immune-mediated glomerulonephritis.”
Acute Glomerular Nephritis: diagram
Nephrotic syndome: as seen on microscope
What you need to know about glomerular diseases
- circulating immune complexes - produce injury to epithelial cells -deposits- antigen in the basement membrane
- or antibody/antigen reaction-antibodies to antigens that exist in the basement membrane
Renal Amyloid
Glomerular Nephritis
Pathogensis of Glomerular Nephritis
- Damage to GBM
- Fibrin in the Bowmans space
- fibrin, macrophages, and parietal cell proliferation for crescent
