Module 7 Flashcards
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
What is the abundance of juxtamedullary nephrons and what are they useful in forming?
10-15%, useful in forming very concentrated urine in low water availability conditions.
How do Nephrons make urine?
by filtering plasma out of blood, then reabsorbing things back out of the filtrate, and then secreting things back into the filtrate.
- __________ and 2. _________ of the afferent and efferent arterioles affect the hydrostatic pressure in the glomeruli which directly influences the amount of filtration that occurs.
- CONSTRICTION
- DILATION
Fill in the blanks for the pathway of urine formation.
glomerulus
▼
____________
▼
_____________
▼
loop of henle
▼
distal convoluted tubule
▼
______________
▼
ureter
▼
urinary bladder
▼
urethra
glomerulus
▼
Bowman’s capsule
▼
proximal convoluted tubuled
▼
loop of henle
▼
distal convoluted tubule
▼
collecting duct
▼
ureter
▼
urinary bladder
▼
urethra
T or F
In aldosterone, increases in blood pressure cause increases in the volume of plasma filtered and decreases in blood pressure cause decreases in the volume of plasma filtered.
TRUE
T or F
In Aldosterone more water is reabsorbed which decreases blood volume and blood pressure
False, INCREASES blood volume and blood pressure
When blood pressure increases and the walls of the atria stretch, they release what?
Atrial natriuretic peptide (ANP)
what triggers less sodium to be reabsorbed from the filtrate during the production of urine leading to less water reabsorption, decreasing blood volume and, therefore, blood pressure.
Atrial natriuretic peptide (ANP)
increase in ADH release from the posterior pituitary gland is caused by what 3 things?
- increase in plasma osmolarity,
- increase in the activity of the hypothalamic osmoreceptors
- when decrease in BV or BP leads to decrease in the activity of aortic and carotid baroreceptors.
what allows more water to be reabsorbed decreasing the osmolarity of blood by increasing its water content and increasing blood volume and blood pressure?
increase in ADH release from the posterior pituitary gland
The _________ are capillary beds at the front of each ___________ from which __________is filtered to begin the formation of urine.
- glomeruli
- nephron
- plasma
What cup-shaped structure leads into the nephron?
Bowman’s capsule
What is the proximal convoluted tubule responsible for?
reabsorb many things such as glucose, amino acids, sodium, chloride, and water from the filtrate and move them into the peritubular capillaries.
what percentage of the filtrate remains in the nephron as it leaves the PCT?
only 35%
The descending limb of the loop of Henle is made of 1. what cells which are permeable to 2. ___________ but impermeable to 3.__________, so more water is reabsorbed out of the filtrate and the filtrate becomes 4. (more/less) concentrated in the descending limb.
- simple squamous epithelial cells
- water
- salt
- more
ascending limb of the loop of Henle is made of 1.___________ and 2. _____ __________ epithelial cells which are permeable to 3. ______ but not to 4. _________, so more solutes are removed from the filtrate and the filtrate becomes 5.(concentrated/dilute).
- cuboidal
- low columnar
- salt
- water
- dilute
Primary function of the Distal convoluted tubule?
secretion of some solutes back into the filtrate.
What structure collects urine from many nephrons and carries it towards the renal pelvis.
collecting ducts
_________ carry urine to the urinary bladder.
ureters
Urination or micturition is both under voluntary and involuntary control. (T/F)
TRUE
As the bladder fills,1. _________ _______ send signals to the micturition center in the spinal cord which activate the 2.______________ neurons that trigger contractions of the 3.__________ muscle that lines the bladder and relaxation of the internal sphincter muscle.
- stretch receptors
- parasympathetic
- detrusor
What is the tube through which urine leaves the body called?
urethra
