Ch44_ Animal Excretory Systems Homework

11/5/2015 Ch44: Animal Excretory Systems Homework

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Ch44: Animal Excretory Systems HomeworkDue: 11:59pm on Monday, November 30, 2015

You will receive no credit for items you complete after the assignment is due. Grading Policy

Chapter 44 Question 33

Part A

Why are the renal artery and vein critical to the process of osmoregulation in vertebrates?

ANSWER:

Correct


Part A

Which of the following animals generally has the lowest volume of urine production?

ANSWER:

Correct


Part A

Increased antidiuretic hormone (ADH) secretion is likely after _____.

ANSWER:

Correct


Part A

A human who has no access to fresh water but is forced to drink seawater instead will _____.

The renal artery and vein are the main pathways regulating how much is produced by the kidneys.

The kidneys require higher than normal levels of hormones.

The kidneys require constant and abnormally high oxygen supply to function.

The renal artery delivers blood with nitrogenous waste to the kidney and the renal vein brings blood with less nitrogenous wastes away from thekidneys.

a vampire bat

a salmon in fresh water

a shark inhabiting the Mississippi River

a marine bony fish

drinking lots of pure water

sweatinginduced dehydration increases plasma osmolarity

eating a small sugary snack

blood pressure becomes abnormally high



ANSWER:

Correct


Part A

Materials are returned to the blood from the filtrate by which of the following processes?

ANSWER:

Correct


Part A

Excessive formation of uric acid crystals in humans leads to _____.

ANSWER:

Correct


Part A

What is the function of the osmotic gradient found in the kidney? The osmotic gradient allows for _____.

ANSWER:

Correct

thrive under such conditions, as long as he has lived at the ocean most of his life

excrete more water molecules than taken in, because of the high load of ion ingestion

develop structural changes in the kidneys to accommodate the salt overload

risk becoming overhydrated within twelve hours

filtration

excretion

selective reabsorption

secretion

gout, a painful inflammatory disease that primarily affects the joints

a condition called diabetes, where excessive urine formation occurs

osteoarthritis, an inevitable consequence of aging

a condition of insatiable thirst and excessive urine formation

the loop of Henle to deliver water to the renal vein

the filtration of large cells at the glomerulus

the precise control of the retention of water and electrolytes

electrolytes to move from low to high concentrations in the absence of ATP




Part A

After blood flow is artificially reduced at one kidney, you would expect that kidney to secrete more of the hormone known as _____.

ANSWER:

Correct


Part A

Urea is produced in the _____.

ANSWER:

Correct


Part A

In humans, the transport epithelial cells in the ascending loop of Henle _____.

ANSWER:

Correct


Part A

The body fluids of an osmoconformer would be _____ with its _____ environment

ANSWER:

angiotensinogen

antidiuretic hormone

atrial natriuretic peptide

renin

bladder from uric acid and water

liver from NH3 and carbon dioxide

liver from glycogen

kidneys from glycerol and fatty acids

are not affected by high levels of nitrogenous wastes

are the largest epithelial cells in the body

are not in contact with interstitial fluid

have plasma membranes of low permeability to water



Correct


Part A

Osmoregulatory adjustment via the reninangiotensinaldosterone system can be triggered by _____.

ANSWER:

Correct


Part A

The advantage of excreting nitrogenous wastes as urea rather than as ammonia is that _____.

ANSWER:

Correct


Part A

If ATP production in a human kidney was suddenly halted, urine production would _____.

ANSWER:

Correct


isoosmotic; saltwater

hyperosmotic; saltwater

hypoosmotic; saltwater

isoosmotic; freshwater

eating a pizza with olives and pepperoni

severe sweating on a hot day

drinking several glasses of water

sleeping for one hour

urea is less toxic than ammonia

urea can be exchanged for Na+

urea does not affect the osmolar gradient

less nitrogen is removed from the body

decrease, and the urine would be isoosmotic compared to plasma

decrease, and the urine would be hypoosmotic compared to plasma

increase, and the urine would be isoosmotic compared to plasma

increase, and the urine would be hyperosmotic compared to plasma



Part A

A primary reason that the kidneys have one of the highest metabolic rates of all body organs is that _____.

ANSWER:

Correct

Make Connections: Kidney Function and Passive and Active Transport

The human kidney produces highly concentrated urine through the passive and active transport of NaCl, urea, and water. Click on the figure at left to reviewpassive and active transport. Click on the figure at right to review how urine concentration occurs in the nephron. The concentration of urine in the kidney is animportant adaptation to a terrestrial existence.

Part A Reviewing passive and active transport

Both passive and active transport are used to move molecules into and out of cells, as shown in the figure. Identify the key differences between passiveand active transport, and provide an example of each.

Drag the labels to their appropriate locations in the table below. Use only pink labels for pink targets, blue labels for blue targets, and whitelabels for white targets.

ANSWER:

they are the body's only means of shedding excess nutrients

they have membranes of varying permeability to water

they operate an extensive set of activetransport ion pumps

they have an abundance of myogenic smooth muscle



Correct

The production of concentrated urine by the kidneys requires both passive and active transport.

Passive transport is used to move molecules down a concentration gradient from where they are more concentrated to where they areless concentrated. Passive transport does not require energy from cells.Active transport is used to move molecules against a concentration gradient from where they are less concentrated to where they aremore concentrated. Active transport requires energy from cells.

Part B Urine concentration in the kidney

The figure shows how urine concentration occurs in the nephron, the functional unit of the vertebrate kidney.

Drag the terms on the left to the appropriate blanks on the right to complete the sentences. Not all terms will be used.

ANSWER:



Correct

The kidneys concentrate urine by establishing an osmolarity gradient between the cortex and the medulla. Passive and active transport both play arole in this process.

Through active and passive transport, NaCl helps establish and maintain the osmolarity gradient.Through passive transport only, urea also helps establish and maintain the osmolarity gradient.Through osmosis, a form of passive transport, water responds to the osmolarity gradient by leaving the filtrate.

Part C How are passive and active transport used in the kidney?

The regions of the nephron through which filtrate flows are labeled in the figure below.

Drag each statement to the appropriate bin depending on whether it applies to the descending limb of the loop of Henle, the ascending limb ofthe loop of Henle, or the collecting duct.

ANSWER:



Correct

The passive and active transport of NaCl and the passive transport of urea create an osmolarity gradient between the cortex and medulla of thekidney. As the filtrate moves through the nephron, water leaves the filtrate by osmosis. The loss of water results in urine that is highly concentrated.Antidiuretic hormone (ADH) also helps to regulate urine concentration by controlling NaCl transport and water permeability in the collecting duct.The active transport of NaCl in the loop of Henle and collecting duct requires a significant amount of energy. This transport, along with other activetransport systems in the kidney, explains why the kidney has one of the highest metabolic rates of any organ in the body.


Part A

The high osmolarity of the renal medulla is maintained by all of the following EXCEPT _____.

ANSWER:

Correct


Part A

One of the waste products that accumulates during cellular functions is carbon dioxide. It is removed via the respiratory system. What is another wasteproduct that accumulates during normal physiological functions in vertebrates?I) ammoniaII) uric acidIII) urea

ANSWER:

active transport of salt from the upper region of the ascending limb

the spatial arrangement of juxtamedullary nephrons

diffusion of urea from the collecting duct

diffusion of salt from the descending limb of the loop of Henle



Correct


Part A

To maintain homeostasis freshwater fish must _____.

ANSWER:

Correct


Part A

Antidiuretic hormone (ADH) and the reninangiotensinaldosterone system (the RAAS) work together in maintaining osmoregulatory homeostasis throughwhich of the following ways?

ANSWER:

Correct


Part A

Compared to the seawater around them, most marine invertebrates are _____.

ANSWER:

Correct

only II and III

only I and II

I, II, and III

only I and III

excrete large quantities of water

take in electrolytes through simple diffusion

excrete large quantities of electrolytes

consume large quantities of water

ADH regulates the osmolarity of the blood by altering renal reabsorption of water, and the RAAS maintains the osmolarity of the blood bystimulating Na+ and water reabsorption.

ADH and the RAAS combine at the receptor sites of proximal tubule cells, where reabsorption of essential nutrients takes place.

Both stimulate the adrenal gland to secrete aldosterone, which increases both blood volume and pressure via its receptors in the urinary bladder.

ADH and the RAAS work antagonistically; ADH stimulates water reabsorption during dehydration and the RAAS causes increased excretion ofwater when it is in excess in body fluids.

isoosmotic

hyperosmotic

hypoosmotic

hyperosmotic and isoosmotic



Kidney Structure and Function

The excretory system of mammals relies on a pair of kidneys that maintain water and electrolyte balance in the body. Hormones such as antidiuretic hormone(ADH), aldosterone, and atrial natriuretic peptide (ANP) regulate kidney function.

Part A Identifying the structures of the kidney

Label the diagram of the kidney and nephron below.

Drag the labels to their appropriate locations on the diagram below. Labels can be used once, more than once, or not at all.

Hint 1. What are the structures of the kidney?

Drag the terms on the left to the appropriate blanks on the right to complete the sentences.

ANSWER:

Hint 2. How does filtrate flow in the nephron?

Describe the path that filtrate follows through the nephron before reaching the urinary bladder.

Drag the phrases onto the flowchart in the order in which filtrate flows through the nephron.

ANSWER:



ANSWER:

CorrectThe nephron is the functional unit of the kidney, meaning that filtrate is processed in the nephrons. Nephrons are positioned in the renal cortex andcan extend into the renal medulla. A nephron consists of a glomerulus and a long tubule that includes Bowman's capsule, the proximal tubule, theloop of Henle, and the distal tubule. Filtration occurs at the glomerulusBowman’s capsule interface, sometimes called the renal corpuscle. The filtratethen travels through the rest of the nephron and drains into the collecting duct. The filtrate, now called urine, exits the kidney through a ureter thatdrains into the urinary bladder. Finally, the urine is expelled from the body through the urethra.

Part B Water conservation by the kidney

The kidneys of terrestrial mammals conserve water in the body by concentrating urine. The osmolarity of human blood is 300 mOsm/L, but human urine isgenerally about 1200 mOsm/L. The loop of Henle and the collecting duct are instrumental in maintaining osmotic gradients that make the concentration ofurine possible.Complete the diagram below using the following steps:

1. Place the pink labels, which indicate interstitial fluid osmolarity in mOsm/L, onto the correct pink targets. (Note that the numbers inside thenephron and collecting duct indicate the osmolarity of the filtrate at those different points.)

2. Place a red arrow to indicate active transport or a purple arrow to indicate passive transport onto the remaining targets. Do H2O, NaCl, andurea experience active transport, passive transport, or both? Keep in mind that the nephron's epithelium exhibits varying permeability towater and solutes along its length.

Labels can be used once, more than once, or not at all.

Hint 1. Active transport and passive transport

Active transport systems require energy such as ATP to transport substances across a membrane, such as when a solute is transported againstits concentration gradient. Passive transport systems, such as diffusion and osmosis, do not require energy. Water and solutes diffuse down theirconcentration gradients.

Hint 2. Definition of osmolarity

Osmosis is a type of diffusion in which water moves across a selectively permeable membrane. Osmosis occurs when two solutions separated bya membrane differ in osmotic pressure, or osmolarity. Osmolarity is a measure of total solute concentration in a solution and is expressed asmilliOsmoles per liter (mOsm/L). Water moves toward the solution of greater osmolarity.Three terms describe differences in osmolarity:

isoosmotic solutions have the same osmolaritya hypoosmotic solution has a lower concentration of solutes, or lower osmolarity, than a second solutiona hyperosmotic solution has a greater concentration of solutes, or greater osmolarity, than a second solution

Differences in osmolarity between the filtrate in the nephron and the interstitial fluid drive the reabsorption and conservation of water in the kidneys.



Hint 3. Which way will water flow?

Assume that a selectively permeable membrane separates two solutions. Given the following situations, determine whether water will flow fromsolution 2 to solution 1, from solution 1 to solution 2, or if there is no net movement of water.

Drag each phrase to the appropriate bin.

ANSWER:

Hint 4. How solutes move out of the loop of Henle and the collecting duct

The movement of solutes out of the loop of Henle and the collecting duct is critical to maintaining the osmotic gradient in the interstitial fluid of thekidney. The fact that the ascending limb of the loop of Henle is impermeable to water ensures that the osmotic gradient is not diluted.

NaCl diffuses out of the thin ascending limb.NaCl is actively transported out of the thick ascending limb.Urea diffuses out of the lower collecting duct.

Because the osmolarity of the interstitial fluid increases from the cortex to the medulla, the filtrate becomes concentrated as it flows deeper intothe medulla and water diffuses into the interstitial fluid. This water does not dilute the osmotic gradient because it is reabsorbed into thebloodstream.

ANSWER:



Correct

Water is reabsorbed in the kidney because of the osmotic gradient established in the interstitial fluid. The osmolarity of the interstitial fluid increasesdeeper into the medulla. As a result, water diffuses out of the descending limb of the loop of Henle and out of the collecting duct, flowing from areasof lower osmolarity in the filtrate to areas of higher osmolarity in the interstitial fluid. This water diffuses into blood vessels surrounding the nephron,called the vasa recta, returning to the bloodstream and therefore not diluting the osmotic gradient.The osmotic gradient in the interstitial fluid is maintained mostly by NaCl and urea. In the thin portion of the ascending limb of the loop of Henle, NaCldiffuses out of the nephron. In the thick upper portion of the ascending limb, NaCl is actively transported out of the nephron. (The ascending limb isimpermeable to water, which helps maintain high osmolarity in the interstitial fluid.) Urea diffuses out of the lower portion of the collecting duct and isresponsible for the high osmolarity in the inner medulla.After traveling through the nephron and the collecting duct, urine is more concentrated than other body fluids and excretes urea and other wastes witha minimal loss of water. The ability of mammalian kidneys to conserve water in this way is a key terrestrial adaptation.

Part C Hormonal regulation by ADH and aldosterone

You have probably noticed that urine is not always the same. The body is capable of adjusting the volume and the osmolarity of its urine output dependingon a number of factors.The kidneys are regulated by hormones such as antidiuretic hormone (ADH) and aldosterone. These hormones are secreted in response to changes in theanimal's internal water and salt balance. For example, sweating or blood loss can disrupt water and/or salt balance in the body, leading to a hormonalresponse that returns the system to homeostasis. Mechanisms for adjusting blood volume or osmolarity include increasing water and/or sodiumreabsorption in the nephrons and collecting ducts.How do the following stimuli affect water and sodium (Na+) reabsorption in the kidneys?

Drag each item to the appropriate bin.

Hint 1. Effects of ADH and aldosterone

Antidiuretic hormone (ADH) secretion increases in response to an increase in blood osmolarity above the set point of 300 mOsm/L. ADH acts ondistal tubules and collecting ducts, making them more permeable to water and increasing reabsorption of water into the body. This reabsorption ofwater concentrates urine, reduces the volume of urine produced, and acts with drinking to decrease blood osmolarity.Aldosterone is released in response to lowered blood pressure or blood volume. Aldosterone acts on the distal tubules, making them absorb moreNa+ and water, thereby increasing blood volume and blood pressure.

Hint 2. Diabetes insipidus

Diabetes insipidus is a disorder in which the kidneys produce large volumes of dilute urine due to a lack of ADH production or an inability torespond adequately to ADH. Diabetes insipidus can have many causes.

Hint 3. Which stimuli result in the release of ADH?

ADH is secreted in response to an increase in blood osmolarity above a set point. Which of the following stimuli result in the release of ADH?

Select the three that apply.

ANSWER:



Hint 4. Which stimuli result in the release of aldosterone?

Aldosterone is secreted in response to lowered blood pressure or blood volume. Which of the following stimuli result in the release of aldosterone?

Select the two that apply.

ANSWER:

ANSWER:

blood loss

eating salty food

severe diarrhea

dehydration

sweating

dehydration

eating salty food

sweating

blood loss

severe diarrhea



Correct

Antidiuretic hormone (ADH) and aldosterone are two of the hormones that help to regulate blood osmolarity, blood pressure, and blood volume byacting on the kidney.ADH is released from the posterior pituitary gland in response to increased blood osmolarity. Dehydration, sweating, and eating salty foods can allcause blood osmolarity to rise. To counteract that change, ADH acts on the distal tubules and collecting ducts, causing them to become morepermeable to water. As a result, water is reabsorbed, lowering blood osmolarity, concentrating the urine, and reducing urine volume.

Aldosterone is released from the adrenal glands in response to a drop in blood pressure or blood volume. Blood loss and severe diarrhea can bothcause blood pressure and blood volume to drop. To counteract those changes, aldosterone acts on the distal tubules, causing them to reabsorb moreNa+ and water. The reabsorption of both sodium and water results in an increase in blood volume and blood pressure without changing bloodosmolarity.


Part A

After drinking alcoholic beverages, increased urine excretion is the result of _____.

ANSWER:

Correct


Part A

Ammonia _____.

ANSWER:

inhibited secretion of antidiuretic hormone (ADH)

increased reabsorption of water in the proximal tubule

increased aldosterone production

increased blood pressure



Correct


Part A

The figure above shows a nephron. Filtration takes place in the structure labeled _____.

ANSWER:

Correct


Part A

The force driving simple diffusion is _____, while the energy source for active transport is _____.

ANSWER:

has low toxicity relative to urea

is soluble in water

is metabolically more expensive to synthesize than urea

is the major nitrogenous waste excreted by insects

a

b

c

d



Correct

Score Summary:Your score on this assignment is 100%.You received 26.07 out of a possible total of 26 points.

the concentration gradient; ATP

the concentration gradient; ADP

transmembrane pumps; electron transport

phosphorylated protein carriers; ATP

Ch44_ Animal Excretory Systems Homework

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