Term
| The urinary system consists of: |
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Definition
| kidneys, ureters, urinary bladder, urethra |
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Term
| What are the three primary functions of the urinary system? |
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Definition
excretion -
elimination -
homeostatic regulation of volume and solute concentration of blood plasma |
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Term
| In the urinary system, explain "excretion" |
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Definition
The removal of organic waste products from body fluids |
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Term
| In the urinary system, explain "elimination" |
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Definition
The discharge of waste products into the environment |
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Term
| In the urinary system, explain the essential functions of "homeostatic regulation" |
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Definition
1. regulating blood volume and blood pressure - 2. regulating plasma concentrations -
3. helping stabilize blood pH -
4. conserving nutrients (while excreting organic wastes such as urea and urid acid) |
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Term
| The urinary system eliminates dissolved organic waste products generated by how many cells in the human body? |
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Definition
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Term
| Urine is the end product of what organ? |
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Definition
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Term
| What is the end product of the kidneys? |
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Definition
|
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Term
| What are the basic functional units of the kidneys? |
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Definition
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Term
| What is the structural make-up of a nephron? |
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Definition
| A renal corpuscle, made of glomerulus within a cup-shaped Bowman's capsule |
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Term
| What path does blood enter and exit the glomerulus? |
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Definition
Enters through the afferent arteriole -
Exits through the efferent arteriole
HINT: E for Exit |
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Term
| The Bowman's capsule leads into the renal tubule divided into what three regions? |
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Definition
Proximal convoluted tubule -
Loop of Henle via descending limbs and ascending limbs -
distal convoluted tubule, which leads into the collecting ducts |
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Term
| What are the steps in the function of the nephron? |
|
Definition
1. blood brought in by afferent arteriole. Gets filtered in Bowman's capsule.
2. filtrate passes through different parts of renal tube
3. undergoes changes in composition (ions, water, organic nutrients)
4. waste, with very little nutrients and water empty into collecting duct. |
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Term
| What is the specific function of the nephron? |
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Definition
| TO CONVERT FILTRATE INTO URINE |
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Term
| How does the nephron convert filtrate into urine? |
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Definition
1. Reabsorbs all useful nutrients -
2. Reabsorbs >90% of water -
3. Secretes any waste products into tubular fluid that missed the filtration process |
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Term
| What percentage of blood from total cardiac output flows through the kidneys each minute? |
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Definition
|
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Term
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Definition
| Glomerular filtration rate, which determines the amount of filtrate produced per minute |
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Term
| How much filtrate, in a 24-hour period, does the glomerulus secrete? |
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Definition
50 gallons of filtrate, which is
70x the total plasma volume.
OVER 99% gets reabsorbed |
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Term
| What is the sequence of filtration? |
|
Definition
1. Blood flows into Bowman's capsule via afferent arteriole (where it gets filtered) . -
2. Filtered blood leaves Bowman's capsule via Efferent arteriole (remember: E for Exit) -
3. Within the proximal convoluted tubule (PCT) 60-70% of the water and >90% of the dissolved nutrients are REABSORBED. -
4. As filtrate descends the PCT into the Loop of Henle, more water gets reabsorbed, which leaves the residual filtrate highly concentrated.
5. The highly concentrated filtrate travels back up the LoH (ascending limb) toward the distal convoluted tubule (DCT). Water IS NOT recycled at this portion of the LoH. (Must have ADH at this point to reabsorb)
6. Within the DCT and collecting ducts, no more solutes are lost or reclaimed. (Note: Aldosterone can regulate active transport of ions in or out as needed)
NOTE: Aldosterone controls sodium absorption and potassium loss along DCT
7. Urine concentration as it reaches the renal pelvis varies. (Note: DCT and collecting ducts are impermeable to water unless regulated by antidiuretic hormone (ADH)
8. AT THE POINT OF entry into the collecting duct and renal pelvis, the FILTRATE HAS NOW BEEN CHANGED AND IS URINE |
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Term
| Where is urine formed and how does it travel to elimination? |
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Definition
| Urine is formed in the kidneys, travels through the ureter, into the bladder, through the urethra and out into the environment |
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Term
| On average, how much urine collects in the bladder when the urge to urinate appears? |
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Definition
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Term
| What is the maximum average amount of urine a bladder can hold? |
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Definition
|
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Term
| How long can a person not urinate before death occurs? |
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Definition
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Term
| What is the affect of not urinating for 36 hours? |
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Definition
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Term
| After urination, what is the normal average of urine remaining in the bladder? |
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Definition
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Term
| What function moves urine from the ureters to the urinary bladder? |
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Definition
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Term
| The process of urination is coordinated by what reflex? |
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Definition
| micturition reflex (which signals the stretch receptors) |
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Term
| What muscles contract the urinary bladder to force urine out into the urethra? |
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Definition
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Term
| As the urinary bladder fills with urine, what sensory receptors are activated, signaling the urge to urinate? |
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Definition
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Term
| A full bladder can hold up to how much urine? |
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Definition
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Term
| How often do peristalic contractions begin within the kidney to move urine from the ureter to the bladder? |
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Definition
|
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Term
| Where is urine stored prior to urination? |
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Definition
|
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Term
| What are three of the waste products excreted by the urine? |
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Definition
urea -
uric acid -
creatinine |
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Term
| What is the basic process of urine formation? |
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Definition
1. Filtration -
2. Reabsorption -
3. Secretion - |
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Term
| How much blood is filtered through the kidneys every minute? |
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Definition
| 1.2 quarts, which is 25% of the blood pumped by heart |
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Term
| Where are the kidneys located in the body? |
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Definition
| retroperitoneal (behind the peritoneal cavity). On either side of the veterbral column, between T12 and L3. The left kidney is slightly superior to the right kidney |
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Term
| Name the blood supply to the kidney |
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Definition
| renal, segmental, interlobar, arcuate, corticol radiate arteries (interlobular) |
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Term
| Each kidney weighs approximately how much? |
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Definition
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Term
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Definition
| The chemical and physical analysis of urine |
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Term
| What causes variation of composition of urine produced each day? |
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Definition
| metabolic and hormonal events of the body |
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Term
| The COMPOSITION of normal urine reflects what nephron activities? |
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Definition
| filtration, absorption, secretion |
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Term
| How many LITERS of filtrate are produced each day by the glomerulus? How much is reabsorbed? |
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Definition
| 180 liters of filtrate is produced each day by the glomerulus. More than 99% is reabsorbed. |
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Term
| Once the bladder contains about 200mL of urine, which reflex signals the stretch receptors |
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Definition
| Micturition reflex, which signals the stretch receptors, stimulating the need to urinate |
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Term
| At what range of volume will urination occur despite voluntary opposition? |
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Definition
|
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Term
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Definition
| a condition characterized by the lack of voluntary control over urination |
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Term
| In the urination system, what age-related changes start taking place? |
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Definition
Decline in the number of functional nephrons -
reduction of GFR (glomerular filtration rate) -
reduced sensitivity to ADH
problems with micturition reflex |
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Term
|
Definition
| chemical reactions that occur in the body |
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Term
| What balances within the body are essential to homeostasis? |
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Definition
| fluid balance, electrolyte balance, acid-based balance |
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Term
|
Definition
hydrogen ion concentration
Remember: The power of Hydrogen |
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Term
| Which system in the body is the primary source for electrolyte balance? |
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Definition
|
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Term
| Which system in the body is the primary source for electrolyte loss? |
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Definition
|
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Term
| What is extracellular fluid comprised of? |
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Definition
| interstitial fluid, plasma and other body fluids |
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Term
| What percentage of ECF is water? |
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Definition
|
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Term
| The body is in "fluid balance" when... |
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Definition
| the amount of water gained each day is equal to the amount lost |
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Term
| You are in "electrolyte balance" when... |
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Definition
| the amount of ions gained each day is equal to the amount of ions lost each day |
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Term
| You are in "acid-based balance" when... |
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Definition
| the production of hydrogen ions is offset by their loss. |
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Term
| When the body is in acid-base balance, what will the pH range be in? |
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Definition
|
|
Term
| At what percent of dehydration is the body alerted to being thirsty? |
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Definition
|
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Term
| ECF and ICF are classified as how many compartments? |
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Definition
| ECF and ICF are two distinct compartments |
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Term
| As a diffusion medium for distribution of ions, nutrients and waste products, what does the operation of all cells rely on? |
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Definition
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Term
| Regarding cell operation, why is it necessary that water content be tightly monitored and regulated? |
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Definition
| Because water is the diffusion medium for the distribution of ions, nutrients and waste products of cells |
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Term
| An average body contains how many liters of water? |
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Definition
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Term
| Water accounts for what percentage in an adult male and what percentage in an adult female? |
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Definition
| Male = 60% water - Female = 50% water |
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Term
| In the adult male, what percentage is water and what percentage is protein/lipids? |
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Definition
| Male = 60% water, 40% proteins, lipids |
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Term
| In the adult female, what percentage is water and what percentage is protein/lipids? |
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Definition
| Female = 50% water, 50% proteins/lipids |
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Term
| Primary regulatory hormones in the body are: |
|
Definition
Antidiuretic hormone (ADH), which stimulates water conservation and the thirst center - this will raise blood volume and blood pressure
Aldosterone, which controls Na+ absorption and K+ loss along the DCT, -
Natriuretic peptides (ANP and BNP), which reduce thirst and block release of ADH and aldosterone - this will promote fluid loss and lower blood volume and blood pressure |
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Term
| Fluid moves freely within which fluid compartment? |
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Definition
| Extracellular fluid compartment (ECF) |
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Term
| What are the major routes of fluid exchange with the environment? |
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Definition
| water loss, water gains, temperature rise from fever |
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Term
| Sodium (Na+)balance - rate of sodium uptake across the digestive tract is directly proportional to what? |
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Definition
|
|
Term
| How is Na+ lost to the environment? |
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Definition
| Through urine and perspiration |
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Term
| If sodium balance is too low, what two hormones are secreted to get back in homeostasis? |
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Definition
| Sodium too low = secretion of ADH and Aldosterone |
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Term
| If sodium imbalance is too high, what hormone is secreted to get back in homeostasis? |
|
Definition
| The natriuretic peptide, ANP which reduces thirst and blocks the release of ADH and Aldosterone |
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Term
| If blood pressure is too low, what hormones are released? |
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Definition
| ADH and Aldosterone, which stimulate water conservation and the thirst center which promotes the intake of water. This will help (build) raise the blood volume, thus raise blood pressure |
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Term
| If blood pressure is too high, what hormone is released and why? |
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Definition
| Natriuretic peptides ANP and BNP, which reduce thirst and water conservation. The resulting diuresis will result in fluid loss at kidneys, thus lowering blood volume and blood pressure. |
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Term
| What two "pressures" regulate the movement of water and electrolytes to maintain fluid balance? |
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Definition
| osmotic pressure and hydrostatic pressure |
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Term
| glomelular filtration produces filtrate with a composition similar to what? What is the compositional difference? |
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Definition
| filtrate produced by GF is similar to blood plasma, but with no proteins |
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Term
| Most regions of the nephron perform a combination of what two functions? |
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Definition
| reabsorption and secretion |
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Term
| Most water reabsorption takes place along what region of the nephron? |
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Definition
| PCT - proximal convoluted tubule |
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Term
| Why doesn't water reabsorb at the distal convoluted tubule without aid of a specific hormone? What is that hormone? |
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Definition
| The DCT is not permeable to water. The hormone needed for reabsorption at this point is ADH |
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Term
| Shifts in sodium balance result in expansion or contraction of what? |
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Definition
| ECF (extracellular fluid) |
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|
Term
| Potassium balance is not as closely regulated as sodium balance. The retention of potassium occurs when... |
|
Definition
|
|
Term
| Potassium ion excretion increases as... |
|
Definition
| ECF concentrations rise, aldosterone is secreted and pH rises |
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|
Term
Potassium RETENTION occurs when pH rises or falls?
Potassium EXCRETION increases when pH rises or falls? |
|
Definition
RETENTION = when pH falls ---
EXCRETION = when pH rises |
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|
Term
| Water loss is balance by gains such as |
|
Definition
| eating - drinking - metabolic generation |
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Term
| In the average adult, what is the TOTAL water lost each day? How much is lost just through urine? How much water is lost in feces? How much is lost in respiration and perspiration? |
|
Definition
Total water lost each day - 2500 mL ---
Water lost through urine each day = 1200 mL ---
Water lost in feces = 150mL ---
Water lost in perspiration and respiration = 1150mL |
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Term
| A drop in filtration pressure stimulates _________________ to release ____________ and ______________ |
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Definition
| A drop in filtration pressure stimulates the Juxtaglomerular apparatus (JGA) to release RENIN and ERYTHROPOIETIN |
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|
Term
| The PCT reabsorbs what percentage of the filtrate produced? |
|
Definition
|
|
Term
| Release of renin by JGA is activated by which ANS? |
|
Definition
|
|
Term
| Up until fluid reaches the collecting duct, it's known as what? |
|
Definition
| filtrate. Once it reaches the collecting duct, it's known as urine |
|
|
Term
| What is countercurrent multiplication? |
|
Definition
| Active transport between two limbs of the Loop of Henle where fluid is moving in one direction; responsible for concentration of urine in kidney tubules |
|
|
Term
| What does countercurrent multiplication do and where does it occur? |
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Definition
| It occurs in the ascending and descending limbs of the Loop of Henle. Creates osmotic gradient in medulla. Facilitates reabsorptin of water and solutes before DCT. Permits passive reabsorptin of water from tubular fluid. |
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Term
| Filtration occurs exclusively in the ________ __________ across the ___________ membrane. |
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Definition
| Filtration occurs exclusively in teh renal corpuscle, across the filtration membrane. |
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|
Term
| Water and solute reabsorption occurs primarily along the ________ __________ _________ |
|
Definition
| Water and solute reabsorption occurs primarily along the proximal convoluted tubules (PCT) |
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|
Term
| ACTIVE SECRETION occurs primarily at the _________ and __________ __________ ______________ |
|
Definition
| proximal and distal convoluted tubules (DCT). |
|
|
Term
| Each kidney has approximately how many nephrons? What is the approximate combined length of these nephrons? |
|
Definition
| 1.25 million nephrons --- combined length of the nephrons is 85 miles. |
|
|
Term
| The juxtaglomerular complex secretes what? |
|
Definition
| the enzyme, renin and the hormone, erythropoeitin |
|
|
Term
|
Definition
| part of what makes up the juxtaglomular apparatus. The region where the epithelial cells of the DCT and their nuclei that are clustered together |
|
|
Term
| What percentage of all nephrons are corticol nephrons? |
|
Definition
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