16: Osmotic Regulation and Urinary System Flashcards
Module 3, Lesson 5
____ is determined by how many moles of one or more substances are dissolved in a fluid.
Osmolarity
____ is the ability of a solution to change a cell’s volume by osmosis.
Tonicity
A cell in a(n) ____ solution will lose water to the environment.
Hypertonic
A cell in a(n) ____ solution will gain water and expand.
Hypotonic
A cell in a(n) ____ solution will not change in volume.
Isotonic
True or false:
Tonicity is a relative measure, not a property of the solution itelf.
True
Maintaining ____ requires the exchange of water and electrolytes between the intracellular/extracellular fluids and the environment.
Osmotic balance
List the five major ions in body fluids.
- Sodium
- Chloride
- Calcium
- Magnesium
- Potassium
True or false:
The levels of the five major ions fluctuate widely inside the body fluid.
False
They are maintained at nearly constant levels.
Animals that conform to their environment, such as marine invertebrates, are called…
Osmoconformers
Animals that regulate their internal osmolarity, such as most marine vertebrates, are called…
Osmoregulators
True or false:
All animals living in freshwater must be osmoregulators.
True
All terrestrial animals are…
Osmoregulators
____ is produced by normal cellular activity, particularly the breakdown of amino acids and nucleic acids.
Nitrogenous waste
List the three main types of nitrogenous waste.
- Ammonia
- Urea
- Uric acid
____ is water-soluble, extremely toxic, and produced by amino acid breakdown.
Ammonia
Aquatic animals are easily able to remove ____ through passive diffusion into the surrounding water.
Ammonia
Amphibians, cartilaginous fish, and mammals convert ammonia into…
Urea
Reptiles and birds convert ammonia into…
Uric acid
____ is a less toxic form of ammonia that is still water-soluble.
Urea
The conversion of ammonia to ____ occurs in the liver and requires a lot of water.
Urea
____ is the least toxic form of ammonia, but is not water-soluble.
Uric aci
____ can be excreted without losing a lot of water, but requires energy to produce.
Uric acid
____ are branched tubules within the body that are only open to the outside of the body.
Protonephridia
The blind end of the protonephridia tubules located inside the body are called…
Flame cells
____ have small perforations and cilia that beat to pull small molecules inside.
Flame cells
In ____, water and waste move through the tubules and exit via excretory pores on the animal’s surface.
Protonephridia
____ are a network of tubules that open to both the inside and the outside of the body.
Nephridia
The internal opening of the nephridia is located on the ____, which obtains and filters fluid from the body cavity.
Nephrostome
In nephridia, ____ is removed from the fluid and reabsorbed into body fluids by active transport.
Salt
When invertebrates and many vertebrates excrete urine, it is ____ to the body fluids.
Hypotonic
The osmoregulatory system in insects works by ____ rather than reabsorption.
Secretion
In insects, molecules and ions are transported from the ____ into the ____.
Body fluid ; tubules
In insects, water and ions are actively transported into the ____, creating an osmotic difference that draws water in.
Malphigian tubules
The Malphigian tubules empty into the ____, where most of the water and potassium are reabsorbed.
Midgut
List the three processes used by vertebrate kidneys to produce urine.
- Filtration
- Secretion
- Reabsorption
The primary unit of a vertebrate kidney is the…
Nephron
In kidneys, blood is filtered when it enters the…
Glomerulus
The ____ is a ball of capillaries located inside the Bowman’s capsule.
Glomerulus
Blood pressure forces fluid and small molecules out of the capillaries and into the…
Bowman’s capsule
After leaving the Bowman’s capsule, fluid flows through tubules, where ____ and ____ occurs.
Reabsorption and secretion
After leaving the nephron, urine is stored in the ____ until it is excreted.
Bladder
Freshwater fish can easily excrete waste and ions by…
Passive diffusion
In freshwater fish, the main function of the kidneys is to…
Excrete excess water
____ produce very dilute urine, in which only a small amount of waste is excreted.
Freshwater fish
Marine bony fish are ____ to their environment, so they must conserve as much water as possible.
Hypotonic
Marine bony fish gain water by…
Drinking large amounts of seawater
In marine bony fish, the kidneys are important in excreting ____ that enter the blood.
Divalent ions
Marine fish produce more concentrated urine than freshwater fish, but it is not as concentrated as terrestrial vertebrate urine because…
Other paths exist for ion excretion
Birds and mammals are the only vertebrates whose kidneys can produce urine that is…
More concentrated than their body fluids
The ____ is the structure that enables production of hypertonic urine.
Loop of Henle
List the three main functions of mammalian kidneys.
- Filtration of the blood
- Reabsorption of certain substances from the filtrate
- Secretion of unwanted substances into the filtrate
List the two areas of the kidney contained in the nephron.
- Renal cortex (exterior)
- Renal medulla (interior)
Filtrate exits the nephron as…
Urine
Once urine leaves the nephron, it flows into the…
Connecting duct
Urine leaves the kidney via the…
Ureter
Urine is excreted from the body via the…
Urethra
____ have long loops that extend deep into the renal medulla.
Juxtamedullary nephrons
____ have shorter loops that only go a short distance into the renal medulla.
Cortical nephrons
Blood enters the nephron through the ____, then passes into the glomerulus.
Afferent arteriole
Filtration takes place inside the ____ in the nephron.
Bowman’s capsule
Filtered blood exits the nephron through the…
Efferent arteriole
The substances removed from the blood in the Bowman’s capsule are called…
Filtrate
The efferent arteriole branches into the ____, which interlace with the nephron tubule.
Peritubular capillaries
In nephrons with a loop of Henle, the capillaries surrounding the loop are called the…
Vasa recta
List the functions of the capillaries surrounding the nephron tubule.
(two)
- Enable reabsorption and secretion
- Supply cells in the tubule with oxygen
Filtered blood flows out of the peritubular capillaries and into the…
Renal veins
After filtrate leaves the Bowman’s capsule, it first flows through the…
Proximal convoluted tubule
After filtrate exits the proximal convoluted tubule, it flows into the…
Loop of Henle
After fluid flows through the loop of Henle, it ascends into the…
Distal convoluted tubule
Filtrate flows through the distal convoluted tubule and into the…
Collecting duct
The collecting duct flows through the renal medulla and into the…
Renal pelvis
List the path of filtrate through the nephron.
(seven)
- Glomerulus
- Bowman’s capsule
- Proximal convoluted tubule
- Loop of Henle
- Distal convoluted tubule
- Connecting duct
- Renal pelvis
Most of the ____ that enters the Bowman’s capsule is reabsorbed and leaves the nephron by osmosis.
Water
The gradient that enables water to leave the nephron through osmosis is formed by…
Actively transporting sodium ions out of the filtrate, causing chloride ions to follow them
Reabsorption of water occurs in the…
(three locations)
- Proximal convoluted tubule
- Descending loop of Henle
- Collection duct
Reabsorption of glucose, salt, and other nutrients occurs by active transport in the…
Proximal convoluted tubule
Secretion of nitrogenous waste, potassium, and hydrogen ions occurs by active transport in the…
Distal convoluted tubule
As the filtrate is concentrated in the collecting duct, it becomes…
Urine
The processes of filtration, secretion, and reabsorption are vital to homeostasis because they…
Regulate the balance of water, salt, and acid waste in the body
The amount of ions that are reabsorbed and secreted are controlled by hormones using…
Negative feedback
As you move deeper into the kidney, the ____ creates a gradient of increasing osmolarity.
Loop of Henle
In the ____ of the loop of Henle, water exits passively into the extracellular space.
Descending limb
The descending loop of Henle is thin and impermeable to…
Salt
High osmolarity in the extracellular fluid is generated by the ____ of the loop of Henle.
Ascending limb
In the lower, thinner portion of the ascending limb of the loop of Henle, ____ can passively diffuse out.
Salt
In the upper, thicker portion of the ascending limb of the loop of Henle, ____ is actively transported out.
Salt
The ascending limb of the loop of Henle is impermeable to…
Water
The difference in selective transport in the limbs of the loop of Henle create a…
Concentration gradient
In the loop of Henle, the fitrate’s osmolarity is highest at the…
Base of the loop
In the loop of Henle, the filtrate’s osmolarity is lowest at the…
End of the ascending limb
True or false:
The loop of Henle concentrates the urine.
False
It creates a gradient which is used by other structures to concentrate the urine
Urine is concentrated in the ____ using the concentration gradient.
Distal convoluted tubule and collecting duct
True or false:
Water is lost as it travels deeper into the kidney.
True
The nephron is important in maintaining the balance of ____ in the body.
Salt and pH
Potassium and bicarbonate ions are reabsorbed in the…
Proximal convoluted tubule
Hydrogen ions and any excess ions are secreted into the…
Distal convoluted tubule
The reabsorption of bicarbonate and secretion of hydrogen ions prevents blood from becoming too…
Acidic
Osmoregulation is controlled by hormones that maintain…
(three things)
- Blood pressure
- Blood osmolarity
- Blood volume
Blood osmolarity is monitored by the…
Hypothalamus
____ regulates osmolarity by regulating how much water is reabsorbed into the blood.
Antidiuretic hormone
(ADH)
High osmolarity in the blood pressure results in the secretion of ADH by the…
Posterior pituitary
The secretion of ADH causes the kidneys to…
Allow more reabsorption of water from the filtrate
When ADH is released, collecting ducts and distal convoluted tubules become more permeable to water by…
Placing aquaporins into their cell membranes
When ADH levels are low, aquaporins are…
Stored in vesicles within the cells
When ADH levels are high, aquaporins are…
Inserted into the cell membrane by fusing of the vesicle membrane with the plasma membrane
The release of ADH represents a ____ feedback loop.
Negative
How does the release of ADH affect blood osmolarity, blood volume, and blood pressure?
It decreases them
Aldosterone and atrial natriuretic hormone regulate…
The concentration of solutes in the blood
____ causes reabsorption of salt from the filtrate, and thus increases reabsorption of water.
Aldosterone
____ decreases reabsorption of salt and water from the filtrate.
Atrial natriuretic hormone
(ANH)
