Urinary System Flashcards
Another word for urination
Micturition
Nephron
The functional unit of the nephron
The kidney contains over ____________ nephrons that process _________ to form _________.
1 million Blood Urine
What does a renal corpuscle contain?
Glomerilar capsule Glomerulus
The glomerulus is made of
Capillaries
The endothelium of the glomerulus is
Fenestrated
Filtrate
A protein free fluid filtered into glomerular capsule
Podocytes
Modified epithelial cells with filtration slits
Where are the most podocytes located?
In the capillaries of the golmerulus
What molecules are too large to fit through the filtration slits?
Proteins
What are the different types of neurons?
Juxtamesullary nephron Cortical nephron
Juxta-
Inbetween
Juxtamedullary nephron
Between cortex and medulla. This is the longer of the two nephrons.
What is the purpose of the capillaries surrounding the nephron (vasa recta/peritubular capillaries)?
They help with reabsorption
The urinary system regulates…..
Total water volume in the body and total concentration of dilutes in water (Osmolarity 390 mOsM)
Functions of the urinary system
Regulates total water volume in the body and total concentration of dilutes in water, regulates concentrations of various ions in the ECF, ensure long term acid base balance, ex creating metabolic wastes, produce EPO and renin, convert vitamin D it’s active form, carry out glucogenesis during prolong fasting
What are some metabolic wastes excreted by the urinary system
Creatinine Urea Utica acid
What are the components of the urinary system
Kidneys Paired ureters Urinary bladder Urethra
What are the three major divisions of the kidney
Renal cortex Renal medulla and renal pelvis
What are the major blood vessels of the kidney
Renal artery and renal vein
How much of the total cardiac output passes through the kidney each minute?
1/4 of total cardiac output
Filtrate is filtered into the
Glomerular capsule
Tubular elements
PCT Nephron loop DCT Collecting duct Each has distinct epithelial cells to carry out a specific function
_____ of nephrons are __________.
85% Cortical nephrons
_______________ nephrons play an important role in producing ___________ urine
Juxtamedullary Concentrated urine
Cortical nephron has/is
Short nephron loop Golmerulus further from the cortex-medulla junction Efferent arteriole supplies peri tubular capillaries
A juxtamedullary nephron has/ is
Long nephron loop golmerulus closer to the cortex-medulla junction Efferent arteriole supplies vasa recta
What are The three major renal processes that lead to urine production?
- Glomerular filtration 2.Tubular reabsorption 3. Tubular secretion
Glomerular filtration
Passive process using hydrostatic pressure to move fluids Filtrate is cell and protein free Dumping wastes into trashcan
Tubular reabsorption
Selectively moving substances from the filtrate into the blood Reclaims glucose amino acids 99% water and salt etc. Reclaiming what the body needs All else becomes urine
Tubular secretion
Selectively adding to the trashcan Occurs the length of the tubule and collecting duct
The kidneys process how much blood derived food every day?
Approximately 180 L of blood derived fluid every day Approximately 1.5 L of this leaves the body as urine
During Golmerular filtration the ____________ allows the passage of ___________ and solutes smaller than plasma proteins
Filtration membrane Water and solutes
What is pushing the blood through the filters during glomerular filtration?
Different types of pressures are pushing the blood through the filters
Glomerular filtration rate (GFR)
The volume of filtrate formed each minute by the activity of 2 million glomeruli
GFR is directly proportional to
Net filtration pressures (NPF) can be altered by changing the diameter of the lumen Total surface area available for filtration in the capillaries Filtration membrane permeability; fenestrations make glomeruli capillaries 1000 times more permeable
What is normal GFR?
122 -125 mL per minute
More than 90 mL per minute GFR indicates
Kidney damage with normal or increased GFR first stage of chronic kidney disease
A GFR of 60 to 89 mL per minute indicates
Kidney damage with mild decreased GFR chronic kidney disease stage 2
A GFR of 30 to 59 mL per minute indicates
Moderate decreased GFR third stage of chronic kidney disease
A GFR of 15 to 29% indicates
Severe decreased GFR fourth stage of chronic kidney disease
Less than 15 milliliters per minute GFR indicates
Dialysis kidney failure stage five in chronic kidney disease
The kidneys auto regulate themselves, how?
The kidneys adjust their own resistance to bloodflow in order to maintain a consistent GFR
A mean arterial pressure below _____ causes ____________ to take over; this is done through _________
80 mmHg Extrinsic controls hormones
How is systemic blood pressure controlled by the kidneys?
- A decrease in blood pressure causes the granular cells of the juxtaglomerular complex of the kidney to release renin 2. Renin activate angiotensin 1 through a cascade of chemical reactions 3. angiotensin 1 converts to angiotensin II with the help of ACE or angiotensin converting enzyme 4. Angiotensin II increases aldosterone secretion by the adrenal cortex as well as vasoconstriction of the systemic arterioles; this causes an increase in peripheral resistance 5. Increase in sodium reabsorption by the kidney tubules; water follows the sodium 6. Because of the increase of fluid in the blood blood volume increases 7. The increase in blood volume causes systemic blood pressure to increase
GFR can also be an indication of ________
heart problems
Where is the highest activity of reabsorption taking place and what is being reabsorbed and put into the filtrate?
In the proximal conviluted tubule
- NaCl (sodium)
- Bicarbonate
- Glucose
- Amino Acids
- H2O
- some drugs and poisons
- hydrogen ions
What substances are being secreted in the loop of henle?
salt and water
What substances are being reabsorbed and taken out
of the filtrate at the distal conviluted tubule?
NaCl is leaving and K+ and some drugs are being reabsorbed
What things are being absorbed and reabsorbed at the collecting duct?
Water, salt, and urea are being reabsorbed. Potassium is being secreted.
In the nephron which substances are reabsorbed by active transport?
Salt, Bicarbonate, Amino acids, Glucose
In the nephron what substances are being secreted by active transport?
Potassium ions, Hydrogen ions, drugs and poisons
In the nephron what substances are being reabsorbed by passive transport?
Water and urea
Where is the urine sent after it leaves the collecting duct?
The renal Pelvis
The collecting duct is
The last chance to reabsorb water and salt
_____________ causes less water to be reabsorbed, ______________ causes water to be reabsorbed.
- Increased water intake
- dehydration
What is responsible for water reabsorption?
Aquaporins
Reabsorption in the kidney can be ____________ or ____________
Active or passive
What is the most abundant cation in the filtrate? How is it filtered?
- Sodium
- It is filtered by active transport; a large amount of energy is spent on reabsorbing it
ADH
Antidiuretic hormone; cases the reabsorption of water
The kidney controls long term blood pressure? T/F
True; the brain controls short term blood pressure changes
What inhibits ADH?
alcohol
A low GFR can also be a sign of
diabetes
In the kidney most substances other than sodium use..
secondary active transport
- Sodium
- Glucose
- Amino acids
- Vitamins
- Ions
In the nephron passive transport moves …
Water, lipid soluable substances, various ions and urea
___________ help to absorb water in the PCT. They are always present in the PCT.
Aquporins
________ regulates aquaporin presnce in the __________, aquaporins are not always present here.
- ADH
- Collectind duct
Renal transport can reach maximum function, which means the transport proteins are overwhelmed with substances, this is bad because it can lead to what?
excess substance being secreted into the urine such as glucose with diabetes
In DCT & Collecting Duct
- Reabsorption is fine tuned by hormones according to bodily needs
_______ inhibits urine output and prevents wide swings in water balance.
ADH
Why would low BP cause ADH release?
in order to keep water to increase the volume of the blood and raise blood pressure
Tubular secretion
- Reabsorption in reverse
- Moving Hᶧ, Kᶧ (excess), ammonia, creatinine, urea back to the filtrate
- Disposing of certain drugs/ toxins that are bound to plasma proteins
- Control of blood pH
- Once all substances are reabsorbed and secreted to maintain homeostasis, the remaining substances and fluid are excreted as urine
How is blood pH controlled during tubular secretion?
- A low Blood pH causes the tube to secrete more hydrogen ions and absorbe more bicarbonate ions.
- A high pH causes Chloride ions to be reabsorbed and bicarbonate ions to leave in urine.
If we were so over hydrated that we no ADH ….
- osmolarity of ecf would decrease
- ADH secretion by posterior pituitary would decrease
- the number of aquaporins in coloecting duct would decrease
- this would lead to less H2O absorption in the collecting duct
- large volume of dilute urine
if we were so dehydrated that we had maximal ADH…
- increased osmolarity of ECF
- increased ADH
- increased number of aquaporins in the collecting ducts
- increased H2O absorption in collecting ducts
- Small volume of concentrated urine
In 24 hours, your kidneys filters through how much blood through your golmeruli and tubules?
150-180 liters
how much urine is produced in 24 hrs?
1-2 liters
Normal urine characteristics
–Ranges from pale to deep yellow (color breakdown of Hb)
–Slightly aromatic in odor
–pH is slightly acidic (~6)
–Solutes found in urine include sodium, potassium, urea, uric acid and others
–Glucose in urine is BAD!
Glucosuria
- glucose in the urine
- indication of diabetes melletus
proteinuria or albuminuria
- protein in urine
- caused by:
- pregnancy
- physical exertion
- heart failure
- extreme hypertension
- golmerulonepheritis- intial sign of asymptomatic renal disease
Ketonuria
- ketons in urine
- caused by starvation and untreated DM2
hemoglobinuria
- hemoglobin in urine
- caused by transfusion reaction, hemolytic anemia and sevre burns.
bilirubinuria
- Bile pigments in urine
- caused by liver diseases or an obstruction of bile ducts between the liver and the gallbladder
hematuria
- blood/red blood cells in urine
- caused by bleeding urinary tract due to trauma, kidney stones, infection or cancer
Pyuria
- white blood cells in urine
- caused by infection
thirst mechanism
- driving force that makes you drink when you are thirsty
- this happens when there is more soluts in the blood and less water
- an increase of plasma solutes of 2-3% will trigger thirst mechanism
How does your thirst mechanism work?
- increase in plasma solutes
- decrease in saliva and drymouth
- osmorecepters in hypothalamus are stimulated
- message is sent from thist center in hypothalamus
- this causes the sensation of thirst
- you take a drink
- water moistens mouth, streches stomachand small intesines
- water is absorbed by GI tract
- Plasma solutes increase
