Module 7 Flashcards
(46 cards)
The overall function of the excretory system can be described by what equation:
excretion = filtration + secretion - reabsorption
T or F
The amount of a substance excreted from the body in urine is equal to the amount filtered into the urine from the bloodstream plus the amount secreted into the urine from the bloodstream minus the amount reabsorbed from the urine back into the bloodstream.
TRUE
the bulk-flow of protein-free plasma from the glomerular capillaries into the Bowman’s capsule to form an ultrafiltrate that is not yet urine
Filtration
what is the average glomerular filtration rate (GFR) ?
125 ml/min or 180 L/day
what is used to calculate experimentally determined GFR for a specific case scenario
the renal clearance of insulin
True or False
(GFR x Px) (1440 min/day) = how much of a substance gets filtered in a day
Px = the concentration for substance X in the plasma
True
Filtration is based on what?
The starling forces
the sum of the forces that oppose and favor filtration
The Starling Forces
4 Functions of Excretory System
- elimination of waste materials
- regulation of body fluid volume
- regulation of fluid ion concentrations
- regulation of pH of plasma
The Starling Forces that oppose filtration are what?
- the Bowman’s capsule hydrostatic pressure (due to the interstitial fluid around the Bowman’s capsule)
- the glomerular capillary oncotic pressure (due to the proteins found in the plasma).
the passive and active movement of substances from the filtrate in the nephron back into the blood in the peritubular capillaries
substances such as: water, glucose, amino acids, vitamins, bicarbonate ions, and the chloride salts of potassium, sodium, calcium, and magnesium
Reabsorption
True or False
Reabsorption CANNOT occur anywhere in the tubule?
FALSE, it can occur anywhere from the proximal convoluted tubules to the collecting ducts, but different parts of the tube are permeable to different substances.
Blood flows through the __________ where urine is removed from the blood.
Kidneys
Kidneys are:
- paired
- retroperitoneal
- ______ grams
- ______ cm long
- ______ cm wide
- paired
- retroperitoneal
- 160 grams
- 12 cm long
- 6 cm wide
T or F
To calculate how much of something is reabsorbed per day, the original equation that describes what happens in the system can be used (excretion = filtration + secretion - reabsorption)?
True
the movement by active transport of substances from the blood in the peritubular capillaries that surround the nephron to the filtrate inside the nephron.
substances: ammonia, hydrogen ions, potassium, and some drugs
secretion
Regulation of kidney function is achieved by what 2 factors?
intrinsic and extrinsic factors to the system
What is the flow of urine?
kidneys > renal pelvis > ureters > urinary bladder > urethra
what are the 4 extrinsic factors of kidney function?
- Systemic blood pressure
- Aldosterone
- Atrial natriuretic peptide (ANP)
- Antidiuretic hormone (ADH)
Urine is formed inside the kidney in structures called _________.
nephrons
Which type of nephron accounts for about 85-90% of nephrons found in humans and have a shorter loop of Henle than the other type of nephrons?
Cortical Nephrons
T or F
The extrinsic factors all work by positive feedback loops to maintain homeostasis in the system.
False, NEGATIVE feedback loops
T or F
Aldosterone and ANP affect sodium reabsorption which affects water reabsorption secondarily, and ADH affects water reabsorption directly.
True
Renin converts angiotensinogen that is released by the liver into 1.____________. ACE (angiotensin converting enzyme) secreted by the lungs converts 2. what to what?
- angiotensin I
- angiotensin I into angiotensin II