Mod Lecture 1: FULL GU and ... Flashcards
Exam 1
Renal regulation: Purpose is to conserve:
Conserve nutrients
Renal Regulation: What does the kidney excrete?
Excretion of nitrogenous metabolic waste products
Urea, uric acid, creatinine
Metabolic waste and drug excretion & drug detoxification
What are examples of nitrogenous metabolic waste products?
Urea, uric acid, creatinine
Renal Regulation: What doe the kidneys do with hormones?
Hormone synthesis & breakdown
Renal regulation: What does it balance?
Acid–base, water, electrolyte balance
Renal regulation leads to endocrine regulation of:
Endocrine regulation of insulin, extracellular fluids, ions, volume & BP
Renal Regulation leads to endocrine control of:
Endocrine control of Ca-Po4 metabolism (Vit D activation, PO4 excretion)
What does the renal system perform?
Performs gluconeogenesis
Components of the Renal System?
- Kidneys
- Ureters
- Urinary Bladder
- Urethra
Kidney function
Eliminates waste from the blood
Helps regulate water concentration
Helps regulation blood pressure
Helps maintain a constant blood pH
Ureter function
Transport urine to the urinary bladder
Urinary bladder function
Stores urine,
contracts to eliminate stored urine
Urethra function
Transports urine to the outside of the body
Moves urine from bladder to urinary meatus
Renal/GU Anatomy includes:
Renal capsule
Renal cortex
Renal artery
Renal pelvis
Ureters
Bladder
Urethra
Nephrons
Arterioles
Glomerulus
Renal capsule in the kidney
Surrounding connective tissue
Renal cortex of the kidney
Contains nephrons
The outer layer of the kidney is called the cortex.
Renal artery of the kidney
Supplies blood
Renal pelvis of the kidney
Funnel for urine flowing to ureter
Ureters
Urine from calyces –> bladder
How long is a male’s urethra? How long is a female’s urethra?
6-8” males > 1.5” females ~ UTI risk
How many nephrons are on each kidney?
1–2 million per kidney
Where are nephrons located?
Located in the cortex and medulla
What does the nephrons do?
Filters plasma
Responsible for passing urine into collecting ducts
Reabsorbs and secretes (Tubular reabsorption and secretion)
What do nephrons form?
Forms a filtrate of protein-free fluid
What does the nephron regulate?
Regulates the filtrate to maintain fluid volume, electrolytes, and pH
Glomerulus
Cluster of capillaries ~ filters blood
The glomerulus receives how much blood?
Receive about 1-2 L blood/minute
How much blood is filtered through the glomerulus and where does it go?
120-140 ml blood/min is filtered (180L/day) & passes into Bowman’s capsule
Of the 180L/day that is filtered by the glomerulus, how much is reabsorbed by peritubular capillaries?
178L or more of filtrate is reabsorbed by peritubular capillaries 1 -2 L urine/day
Water, electrolytes
Slide 9
Study if you have time
Parts of the nephron?
- Glomerulus
- Proximal Tubule
- Loop of Henle
- Distal Tubule
- Collecting duct
Different Renal Function Tests
- GFR
- Creatinine Clearance
- Blood Urea Nitrogen
- Serum Creatinine (SCr)
- Urinalysis
What is the best estimate of renal functioning renal tissue, used for drug dosing? highlighted red point
GFR
What does GFR measure?
Flow rate of filtered fluid through the kidney
The filtration of the plasma per unit of time is known as the glomerular filtration rate (GFR)
glomerular filtration rate (GFR)
The filtration of the plasma per unit of time is known as the glomerular filtration rate (GFR)
What are normal GFR values?
Normal GFR 90 to 120 ml/min
eGFR
eGFR = Expressed as a single equation that accounts for gender and race
Estimated Glomerular Filtration Rate
How is GFR determined? Highlighted red point*
Determined by perfusion pressure in the glomerular capillaries
is directly related to the perfusion pressure of the glomerular capillaries
??????
The Modification of Diet in Renal Disease (MDRD) Study equation and the Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) equation
Creatinine Clearance (CrCl)- what is it; what is it an estimate of
Volume of blood plasma cleared of creatinine per unit time
Estimate of GFR
Blood Urea Nitrogen (BUN)
End-product of protein metabolism is urea
Liver & renal function
measures the amount of urea nitrogen in your blood, which is a waste product that your kidneys remove.
Serum Creatinine (sCr) is filtered where?
Filtered at the glomerulus
A small amount of serum creatinine is secreted by what?
Small amt secreted by renal tubules
What is a better indicator of renal functioning SCr or BUN?
SCr Indicator of renal function > BUN
Urinalysis-normal results
Normal: pale yellow, clear
pH 4.6-8
SG ~ 1.001 – 1.035
Urinalysis-sign of UTI
Cloudy, foul-smelling, turbid, WBC ~ UTI
Urinalysis-sign of dehydration
Dark yellow ~ dehydration
Urinalysis-sign of DKA
Acetone odor
Urinalysis-presence of Proteinuria, hyaline casts
presence of Proteinuria, hyaline casts ~ injured glomerular membrane
Urinalysis-presence of glucose
Glucose ~ DM
Urinalysis-presence ketonuria
Ketonuria ~ fatty acid metabolism
Urinalysis-presence of crystalluria
Crystalluria ~ renal stone formation
Urinalysis- presence of cellular casts
Cellular casts ~ nephrotic syndrome
Urinalysis: Ketones present
Ketones ~ fat metabolism
First three steps to RAAS
- The drop in blood pressure triggers the release ADH from the posterior pituitary
- ADH increases water reabsorption by the kidney by increasing water permeability of the distal tubules and collecting ducts.
- The drop in blood pressure also is detected by kidneys, which responds by secreting renin.
- Renin triggers the formation of angiotensin II, which stimulates release of aldosterone from the adrenal cortex.
- Aldosterone then slowly boosts water reabsorption by the kidneys by increasing reabsorption of Na+
Additional Regulation by Kidneys include:
Vitamin D
pH regulation
ANP/BNP
Erythropoietin
Certain hormones are either activated or synthesized by the kidney. These hormones have significant systemic effects and include:
urodilatin,
the active form of vitamin D,
and erythropoietin.
What is vitamin D needed for?
Needed for Ca absorption
Vitamin D is a hormone that is necessary for the absorption of calcium and phosphate by the small intestine.
How is vitamin D obtained? In what form?
It can be obtained in the diet or synthesized by the action of ultraviolet radiation (sun exposure) on cholesterol in the skin. These forms of vitamin D3 (cholecalciferol) are inactive
What does kidney do to vitamin D?
Renal conversion Vit D to active form
When does reabsorption of renal Ca occur by the kidney?
Reabsorption of renal Ca when levels are low
What does decreased plasma calcium levels cause?
A decreased plasma calcium level (less than 10 mg/dl) stimulates the secretion of parathyroid hormone.
Parathyroid hormone then stimulates a sequence of events to help return the plasma calcium concentration toward normal levels (9 to 10.5 mg/dl)
Parathyroid hormone causes release of Ca from bones, absorption of Ca from intestines, increased renal reabsorption, decreased renal phosphate reabsorption.
When is there increased excretion of Ca by the kidneys? ***THis doesn’t make sense?
Increased excretion when PO4 levels are high
How does the kidney regulate pH?
HCO3 secretion, H+ excretion
ANP/BNP (Natriuretic Peptides)
slide 13
Erythropoietin (Epo)
Erythropoietin (Epo) stimulates the bone marrow to produce red blood cells in response to tissue hypoxia and may have tissue protective effects
What is the stimulus for erythropoietin release?
The stimulus for Epo release is decreased oxygen delivery in the kidneys.
Lack of erythropoietin can be related to what?
The anemia of chronic renal failure, in which kidney cells have become nonfunctional, can be related to the lack of this hormone (erythopoietin)
Changes that occur with aging kidneys:
Structural changes commonly occur in the kidney with aging, including:
loss of renal mass,
arterial sclerosis,
an increased number of sclerotic glomeruli,
loss of tubules, and
interstitial fibrosis.
As number of nephrons decline, what occurs?
As the number of nephrons decreases and degenerative changes occur, nephrons are less able to concentrate urine and less able to tolerate dehydration, excessive water loads, or electrolyte imbalances, particularly with physiologic stress.
What would accelerate the decline of kidney function?
The presence of comordid conditions, such as hypertension and diabetes mellitus, accelerates the decline of renal function.
The process of urination is what kind of process?
Voluntary process
What does urination require?
Functional bladder & stretch receptors that senses bladder filling with urine
Intact parasymp nervous system (PNS) to transmit the signal
Working bladder detrusor muscles to initiate bladder contractions –> urine
Urinary Tract infection
A urinary tract infection (UTI) is an inflammation of the urinary epithelium (mucosa) usually caused by bacteria from gut flora.
Where can a UTI occur?
A UTI can occur anywhere along the urinary tract, including the urethra, prostate, bladder, ureter, or kidney (pyelonephritis).
Who is at risk of UTIs?
At risk are premature newborns; prepubertal children; sexually active and pregnant women; women treated with antibiotics that disrupt vaginal flora; spermicide users; estrogen-deficient postmenopausal women; individuals with indwelling catheters; and persons with diabetes mellitus, neurogenic bladder, or urinary tract obstruction.
Uncomplicated UTIs
Uncomplicated UTIs are mild and without complications and occur in individuals with a normal urinary tract.
Complicated UTIs- how do they develop?
A complicated UTI develops when there is an abnormality in the urinary system or a health problem that compromises host defenses, such as human immunodeficiency virus (HIV), renal transplant, diabetes, or spinal cord injury.
Cystitis
Cystitis is an inflammation of the bladder and is the most common site of UTI.
What is the most common site of UTI?
The bladder
The different types of cystitis?
- Mild cystitis
- Hemorrhagic cystitis
- Suppurative cystitis
- Ulcerative cystitis
- Gangrenous cystitis
Mild cystitis
Mild cystitis shows a hyperemic (red) mucosa.
Hemorrhagic cystitis
shows diffuse mucosal hemorrhages and occurs with more advanced inflammation.
Suppurative cystitis
shows mucosal pus formation or suppurative exudates.
Ulcerative cystitis
results from prolonged infection with ulcers that may lead to sloughing of the mucosa.
Gangrenous cystitis
is necrosis of the bladder wall and occurs with the most severe infections.
What are the most common microorganism to cause UTI? What is the second?
The most common infecting microorganisms are uropathic strains of Escherichia coli, and the second most common is Staphylococcus saprophyticus.
Less common microorganisms to cause UTIs include:
Less common microorganisms include Klebsiella, Proteus, Pseudomonas, fungi, viruses, parasites, or tubercular bacilli.
How does bacterial contamination of the normally sterile urine usually occur?
Bacterial contamination of the normally sterile urine usually occurs by retrograde (backward) movement of gastrointestinal gram-negative bacilli into the urethra and bladder from the opening of the urethra.
The microorganisms can then move into the ureter and kidney.
Clinical manifestations of cystitis are usually related to what?
Clinical manifestations of cystitis are related to the inflammatory response
Clinical manifestations of cystitis are what?
usually include frequency, urgency, dysuria (painful urination), and suprapubic and low back pain. Hematuria, cloudy urine, and flank pain are more serious symptoms.
Many individuals with bacteruria are asymptomatic, what group has the highest risk of this? What may this group experience instead?
Many individuals with bacteriuria are asymptomatic, and the elderly have the highest risk and may have only confusion or vague abdominal discomfort.
Evaluation and Treatment of cystitis?
If a urine culture and sensitivity are ordered, the urine specimen must be obtained before the initiation of any antibiotic therapy; 3 to 7 days of treatment is most common.
What can be used for the diagnosis of uncomplicated UTI?
Urine dipstick testing that is positive for leukocyte esterase or nitrite reductase can be used for the diagnosis of uncomplicated UTI.
What produces the urgency and frequency of urination associated with cystitus?
Inflammatory edema in bladder wall stimulates activation of stretch receptors.
The activated stretch receptors initiate symptoms of bladder fullness with small volumes of urine, producing the urgency and frequency of urination associated with cystitis.
Pyelonephritis
is an infection of one or both upper urinary tracts (ureter, renal pelvis, and kidney interstitium).
WHat are the most common underlying risk factors of pyelonephritis?
Urinary obstruction and reflux of urine from the bladder (vesicoureteral reflux) are the most common underlying risk factors.
How is pyelonephritis spread?
The infection is probably spread by ascending uropathic microorganisms along the ureters.
The inflammatory process involved in pyelonephritis affect what?
The inflammatory process primarily affects the pelvis, calyces, and medulla of the kidney.
What does pyelonephritis cause?
The infection causes infiltration of white blood cells with renal inflammation, renal edema, and purulent urine.
In severe infections of pyelonephritis, what can occur?
In severe infections, localized abscesses may form in the medulla and extend to the cortex.
Clinical manifestations of pyelonephritis include:
The onset of symptoms is usually acute, with fever, chills, and flank or groin pain.
Symptoms characteristic of a UTI, including frequency, dysuria, and costovertebral tenderness, may precede systemic signs and symptoms.
Chronic pyelonephritis
is a persistent or recurrent infection of the kidney leading to scarring of the kidney.
