1 Flashcards
The urinary system is composed of what 4 components?
1) Kidneys
2) Ureters
3) Bladder
4) Urethra
What do the kidneys produce?
Urine, which removes liquid waste products from blood
What part of the urinary system keeps a “metabolic balance of the blood?”
Kidney
What hormones do the kidneys produce?
Erythropeoietin, Calcitriol, and Prostaglandins
What hormone helps with red blood cell production?
Erythropoietin
What is the active form of Vitamin D?
Calcitriol
What do the ureters do?
Carry urine to the bladder
What does the bladder do?
Stores the urine produced
What does the urethra do?
Delivers the urine for excretion outside the body
Where is the left kidney located?
Level of T11 - L2
Where is the right kidney located?
Level of T12 - L3
The renal artery, renal vein, and ureter all leave the kidney through what?
An indention of the hilum (hilus) of each kidney
What covers the kidney?
A capsule
What 4 things consist of the internal kidney?
1) Cortex (including renal columns
2) Medulla (pyramids)
3) Minor Calyces, Major Calyces
4) Renal Pelvis
What endocrine gland is associated with the kidney (located on top)?
Adrenal gland
What is the main functional unit of the kidney?
Nephron
How many nephrons in each kidney?
1 million or slightly more
Where are nephrons located?
Both the renal cortex and the renal medulla
What does the nephron consist of?
Glomerulus, proximal convoluted tubule, loop of Henle, and distal convoluted tubule
Nephrons empty into collecting ducts that run out to the ______
Minor and Major calyx, and renal pelvis
What are the 2 nephron types?
1) Cortical
2) Juxtamedullary
Where are cortical nephrons located, and what appearance do they have?
Located mostly within the cortex, and have short length of the loop of Henle
Where are Juxtamedullary nephrons located and what is their appearance?
Extend deep into the medulla and have long loop of Henle
How do various regions of the nephron differ from one another?
Anatomically, and they consist of different types of epithelium related to their own functions
What are the 4 stages of Urine Formation?
1) Filtration (from blood to kidney)
2) Reabsorption (From kidney back to body)
3) Secretion (from body straight to kidney)
4) Excretion
Where does “Filtration” occur?
In Glomerulus
Where does “Secretion” occur?
Proximal convoluted tubule, loop of Henle, and Distal convoluted tubule
Where does “Excretion” occur?
In collecting duct, minor calyx, major calyx, and renal pelvis
20-25% of the blood leaving the left ventricle of the heart enters _________
The kidneys via renal arteries
Blood passes through the kidneys at a rate of ______
1200 ml/min, or 600 ml/min/kidney **
___1_____ arterioles carry blood to the ____2___ known as the _____3____
1) Afferent
2) Capillary Tuft
3) Glomerulus
___1____ arterioles that contain the remaining blood that was not filtered by the glomerulus form the __2___ in the cortex and ____3___ in the medulla
1) Efferent
2) Peritubular capillaries
3) Vasa Recta
Where are the peritubular capillaries?
Cortex
Where are the Vasa Recta?
Medulla
Where is the glomerulus located?
Between 2 arterioles
Each glomerulus is located in _______
Bowman’s Capsule
What is the outer layer of the Bowman’s capsule?
“Parietal” layer, and it is composed of squamous epithelium (aka parietal epithelial cells)
What is the inner layer of Bowman’s capsule?
“Visceral” layer, and it is composed of specialized cells known as podocytes (aka visceral epithelial cells)
The epithelial layers of the glomerulus rest on what?
A thin basal lamina
What is “Bowman’s Space?”
The space between the outer portion of the capsule and visceral portion of the capsule
Where does the filtrate of the blood pool?
Bowman’s space
What does the glomerulus consist of?
Bowman’s Capsule, Glomerular Tuft, and Juxtaglomerular Apparatus
What are the 3 major components of glomerular capillary wall (They help account for the glomerular filtration)?
1) Endothelial cells with fenestra
2) Glomerular Basement Membrane (GBM)
3) Visceral Epithelial cells, aka podocytes
Approximately 90-120 ml/min, or 1/5th of the renal plasma, is filtered through the glomeruli forming _______
The Ultrafiltrate *
Ultrafiltrate has the same composition as to blood plasma and includes:
Water, Electrolytes, Glucose, Amino Acids, Urea, Uric Acid, Creatinine, and Ammonia
What is a key indicator of kidney function and is used to check how well the kidneys are working, or monitor kidney disease progression?
Glomerular Filtration Rate (GFR)
What does GFR specifically estimate?
How much blood passes through glomeruli each minute
What is the normal result of GFR range?
90-120 ml/min
What is GFR proportional to?
Body size and varies with age and sex
Older people have __1___ normal GFR levels, because GFR ___2__ with age
1) Lower
2) Decreases
GFR test aka:
Clearance Test *
What does the GFR test (glomerular filtration rate) aka clearance test measure?
How well the kidneys are filtering creatinine * which is a waste product of creatine phosphate breakdown in muscles
For the Glomerular Filtration Rate test (GFR), what is required?
1) A 24 hour urine sample
2) Blood sample
When the kidneys aren’t working as well as they should _______ builds up in the blood
Creatinine
What are “Threshold substances?”
Those substances which are almost completely reabsorbed by the renal tubules when their concentration in the plasma is within normal limits
In regards to tubular function, when the normal plasma level is exceeded, what happens?
The substance is no longer totally reabsorbed and it appears in the urine
Glucose is a high threshold substance, T/F?
TRUE
When does glucose appear in the urine?
When plasma concentration exceeds about 160 to 180 mg/dl *
What are some of the other threshold substances in tubular function?
amino acids, creatine, potassium, and sodium chloride
Tubular function of the proximal tubules reabsorbs what?
1) 100% of amino acids, proteins and glucose
2) HCO3
3) K+, NaCl, Ca
4) H20
* NO REABSORPTION OF CREATININE ***
What does the proximal tubule secrete?
1) Uric Acid
2) Organic acids (antibiotics)
3) Creatinine
4) Hydrogen Ion
What is reabsorbed in the Loop of Henle?
1) H20
2) NaCl
3) Ca, Mg
What is secreted from the Loop of Henle?
Hydrogen ion and Ammonia
What is the key feature of the Descending loop of Henle?
PERMEABLE to water *
- Reabsorption of solutes does NOT occur in this part of the loop
What limb of the Loop of Henle is Nearly impermeable to water?
Ascending limb
Which limb of the loop of Henle has hydrogen ion and ammonia secreted?
Ascending Limb
What is the key function of the Ascending Loop of Henle?
Active Resorption of Solute** without water
sodium chloride, calcium, and magnesium
Fluid leaving the loop of Henle has a ___1____ osmolality than plasma because of lost ___2____
1) Lower
2) Sodium Chloride
What do the distal tubules reabsorb?
1) NaCl
2) H20
3) Ca
Not much reabsorption is happening
What do the distal tubules secrete?
1) K+
2) H+
3) Urea
What do the collecting ducts reabsorb?
1) Urea
2) NaCl
3) H20
Not much reabsorption is happening here either
What do the collecting ducts excrete?
1) H20
2) NaCl
3) K+
4) HCO3
5) CREATININE **
About 90% of the glomerular filtrate is reabsorbed by the time it reaches ______
The distal tubule
Where is urea absorbed?
In the Collecting Duct
Is there any reabsorption of creatinine in the “Tubular Reabsorption?”
NO
T/F, some reabsorption is passive and some requires energy for active transport across the cells?
TRUE
What does Tubular Secretion involve?
Sending molecules from the blood into the tubular filtrate
What does the tubular secretion account for?
Removal of unneeded foreign waste substances that are not filtered by the glomerulus including various toxins and medications (such as penicillin)
What type of ions are secreted during “tubular secretion?”
Removal of hydrogen ions and other ions to help regulate acid-base and electrolyte balance
What are the actual ions being being secreted?
ammonium, sodium, potassium, bicarbonate, and uric acid
Within the human body, the blood pH must be maintained within the narrow range of _____
7.35 - 7.45
Maintaining pH within the limits is regulated by proper functions of _______
lungs and kidneys
pH outside the range of 7.35 - 7.45 becomes incompatible with life. What happens during the process?
Proteins of the body are denatured and cells are destroyed enzymes lose their ability to function, and death is possible
What are hydrogen ions produced as?
Waste from metabolism and are generally secreted
What happens to bicarbonates in regards to the “Kidney’s role in Ion secretion and acid-base balance?”
Bicarbonates can be secreted but they are more often reabsorbed, usually up to 100% to help maintain the proper blood pH
What plays a major role in the metabolic acid-base balance?
The kidneys, and they also help with compensation of respiratory acidosis or alkalosis
What are the 3 main functions of the distal and collecting tubules?
1) Adjustment of the pH, osmolality, and electrolytes
2) Secretion of potassium, ammonia, and hydrogen ions
3) Reabsorption of sodium and bicarbonate
What is a region of tissue found in each nephron in the kidney that is important in regulating blood pressure and body fluid and electrolytes?
Juxtaglomerular Apparatus (JGA)
What is a microscopic structure in the kidney that regulates the function of each nephron?
Juxtaglomerular Apparatus (JGA)
What are the 3 cellular components of the JGA?
1) Macula Densa of the distal convoluted tubule
2) Juxtaglomerular cells
3) Mesangial cells
Smooth muscle cells of the afferent arteriole are also known as what?
Juxtaglomerular cells
What do juxtaglomerular cells produce and secrete?
Renin
Mesangial cells secrete what?
Erythropoietin
What is Renin?
An ENZYME produced by the juxtaglomerular cells, it is secreted and reacts with the precursor angiotensin in the blood to convert into angiotensin 1
Angiotensin 1 passes through the lungs where the enzyme ________
Angiotensin Converting Enzyme (ACE) changes it to the active angiotensin II
Angiotensin II results in:
Systemic vasoconstriction including the afferent and efferent arterioles
Angiotensin II results in systemic vasoconstriction by triggering the release of what hormone?
Aldosterone (from the adrenal glands), which increases sodium reabsorption
Besides Angiotensin II triggering the release of Aldosterone, what other hormone does it trigger the release of?
Antidiuretic hormone aka VASOPRESIN, from the posterior pituitary gland
What is aldosterone secreted by?
Adrenal cortex (zona glomerulosa)
What is the most precise thing that aldosterone does?
Increases blood sodium reabsorption in the distal tubules of the nephron, which in turn increases blood volume as water follows salt, raising blood pressure (could contribute to hypertension)
What does aldosterone enhance?
Potassium/sodium ions in distal tubules of the nephron
Andtidiuretic Hormone aka
Vasopresin
Where is ADH aka Vasopresin synthesized?
Hypothalamus
Where is ADH/ vasopressin stored?
In vesicles released from the posterior pituitary gland (neurohypophysis)
What does ADH/vasopresin regulate?
Absorption of water in the collecting ducts
What makes walls of the collecting ducts permeable?
Antidiuretic Hormone/ADH/ Vasopresin
Production of ADH depends on the body’s state of _______
Hydration
Insufficient ADH results in ______
Diabetes Insipidus (DI)
DI (diabetes insipidus) is a problem of 2 possible things, what are they?
1) Decreased production of antidiuretic hormone (Central DI)
2) Abnormal kidney’s response to antidiuretic hormone (nephrogenic DI)
What is “Syndrome of Inappropriate ADH (antidiuretic Hormone) Secretion” characterized by?
Excessive release of antidiuretic hormone from the posterior pituitary gland or another source
Syndrome of Inappropriate ADH Secretion aka
SIADH syndrome
80% of SIADH syndrome is caused by ______ ?
Small cell lung carcinoma (aka oat cell carcinoma)
What might SIADH result from?
Complication of brain injury, tumor growth, and certain medications
What is also characterized by continuous secretion of ADH in spite of plasma hypotonicity and normal or expanded plasma volume?
Syndrome of Inappropriate ADH aka SIADH syndrome
What are the 5 main things Syndrome of Inappropriate ADH secretion results in?
1) High plasma volume
2) Low serum osmolarity
3) Low plasma sodium (hyponatremia)
4) High urine osmolarity
5) Higher than normal urine sodium
In general, increased ADH causes water retention _______
WITHOUT* extracellular fluid volume expansion and without edema or hypertension
When hyponatremia is severe, what symptoms will occur?
Cerebral edema become prominent (irritability, confusion, seizures, and coma)
Fluids filtered at the glomerulus:
90-120 ml/min
Final urine volume Excreted as urine:
1ml/min on average
Dehydration reduces urine production to _____
0.3 ml/min
Excessive hydration increases urine production to ______
15ml/min
Average adult urine daily volume of urine:
1200-1500ml
More urine is produced during _____
the day
What is the normal total urine range ?
600-2000 ml/ 24 hours
What is polyuria?
Abnormal increase in the volume of urine (2500 ml and > per 24 hours), as in diabetes insidious and diabetes mellitus
What is Oliguria?
Decrease in urinary volume, such as occurs in shock and acute glomerulonephritis.
What is oliguria defined as?
Being < 400 ml/24 hr
What is Anuria?
Designates the complete suppression of urine formation
What is Anuria sometimes defined as?
Being < 75 ml/24 hours during 2-3 consecutive days, in spite of a high fluid intake
In 24 hours the body excretes approximately ___1__ of dissolved material, half of which is ___2___
1) 60 g
2) UREA
What is in ABNORMAL urine?
1) Bilirubin
2) Blood
3) Glucose
4) Ketone Bodies
5) Porphyrins
6) Protein
What is in the “sediment” of urine?
1) Cells
2) Crystals
3) Casts
Some of these are considered to be normal, while others are seen in various renal and metabolic disorders
What is inflammation of the bladder?
Cystitis
Nephritis can be present with bacterial infection, what is that called?
Pyelonephritis
Nephritis can be present WITHOUT bacterial infection, what is that called?
Glomerulonephritis
