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Chapter 12

True or False: Extracellular fluid includes interstitial fluid, blood, and lymph.
What is the most abundant waste product of metabolism?
carbon dioxide.
All but which of the following are significant routes for water loss from the body?
a. excretion in urine
b. sneezing
c. sweating
d. elimination in feces
e. evaporation from respiratory surfaces
all but B
What is the process that normally exerts the greatest control over the water balance of an individual?
urinary excretion.
What body systems dispose of a type of waste directly to the environment?
digestive system, respiratory system, integumentary system, urinary system
The most toxic substances routinely found in the blood are metabolites of what type of molelcules?
What solutes would be voided from the vertebrate body under normal conditions?
nutrients, ammonia, urea, carbon dioxide
What is the subunit of a kidney that purifies blood and restores solute and water balance called?
In the kidney, what do the collecting ducts from the nephrons empty immediately into?
renal pelvis.
What is the last portion of the excretory system through which urine passes before it is voided from the body?
What is the functional unit of the kidney?
Where does filtration of the blood in the kidney takes place?
glomerulus of Bowman's capsule.
How is blood delivered to each nephron?
an afferent arteriole.
After the blood leaves the glomerular capillaries, it goes via the efferent arterioles to what kind of capillaries?
peritubular capillaries.
Filtration occurs in which section of a mammalian nephron?
glomerulus in the Bowman's capsule
What is the process called during which potassium and hydrogen ions, penicillin, and some toxic substances are put into the urine by active transport?
tubular secretion.
Which of the following processes is under voluntary control?
a. filtration
b. reabsorption
c. urination
d. secretion
e. excretion
Where do kidney stones form?
renal pelvis.
Which of the following substances is NOT filtered from the bloodstream?
a. water
b. plasma proteins
c. urea
d. glucose
e. sodium
What is the name given to the fluid removed from the blood but not yet processed by the nephron tubules?
glomerular filtrate
What is the process of filtration in the glomerulus driven by?
hydrostatic pressure.
Reabsorption is the movement of water and solutes from the __________ to the __________.
nephron tubules; capillaries
True or False: In reabsorption, nutrients and salts are selectively returned to the blood.
What amount of the fluid removed from the blood is eventually returned to the blood?
greater than 98 percent
Most of the water and sodium is reabsorbed in the ____ of each nephron.
proximal tubule
The reabsorption of solutes is the result of active transport of what substance?
Water reabsorption into the capillaries associated with a nephron is achieved principally by what processes?
active transport and diffusion.
During reabsorption, how do sodium ions cross the proximal tubule walls into the interstitial fluid?
active transport.
Which of the following is actively transported in the proximal tubules of the kidney?
a. bicarbonate ions
b. sodium ions
c. chloride ions
d. water
e. ADH
The longer this structure is, the greater is an animal's capacity to conserve water and to concentrate solutes for excretion in the urine.
loop of Henle
Which of the following features would tend to promote water retention by the kidney?
a. many nephridia
b. a long loop of Henle
c. a long proximal tubule
d. a short distal tubule
e. a high filtration rate
How does a kidney machine removes solutes from the blood?
What is the hormone that influences sodium reabsorption in the kidney?
What is the hormone that controls the concentration of urine?
antidiuretic hormone.
Which of the following is a trigger for the other actions described?
a. Extracellular fluid volume is reduced.
b. Solute concentration in the extracellular fluid rises above a set point.
c. Posterior pituitary secretes ADH.
d. Distal tubules of the nephrons and the collecting ducts become more permeable to water.
e. A small amount of concentrated urine is excreted.
Where does the hormonal control over excretion most likely occur?
distal tubule.
True or False: The antidiuretic hormone promotes processes that lead to a decrease in the volume of urine.
In mammals, what structure governs both the thirst mechanism and the hormonal action that affects the amount of water and solutes excreted in the urine?
When the body has excess sodium, what happens?
More sodium is excreted, Edema (swelling) occurs, Blood pressure rises, Aldosterone secretion is inhibited.
Ethanol (drinking alcohol) is an inhibitor of ADH. Therefore, a person consuming a couple of mixed drinks should excrete
a. less water because ADH promotes reabsorption.
b. the alcohol because ADH cannot degrade it.
c. ketone bodies formed from the alcohol.
d. more water because ADH normally promotes reabsorption.
e. more water and the alcohol due to the ADH inhibition.
In humans, where is the thirst center located?
What influences the pH of the blood and extracellular fluids?
respiration, blood proteins, bicarbonate ions, phosphate and ammonia ions
How does the urinary system help to maintain the extracellular fluid pH?
excreting hydrogen ions as water.
What is the normal pH of the extracellular fluid of the human body?
Hydrogen ions in the blood can be neutralized temporarily by what substance?
What is the usual upper temperature limit before proteins are denatured?
The rate of a chemical reaction is cut in half for a drop of every (degrees fahrenheit)?
What are responses to low temperature that increase the chance for survival?
shivering, production of brown fat, pilomotor response, increased metabolism
Where is the primary thermostat of the body located?
What are some of the initial responses to cold temperature?
shivering, increased respiration, shunting of the blood to the core regions of the body, increased metabolism...
What are the responses to heat stress?
reduction in muscle contraction, increased sweating, dilation of peripheral blood vessels, loss of salts and liquids.
Which of the following statements about fever is NOT correct?
a. Prostaglandins influence the hypothalamus.
b. Fever is the result of a resetting of the body's "thermostat."
c. Low fevers enhance the body's defense mechanisms.
d. When a person feels "chills," the body core temperature is decreasing.
e. Aspirin exerts its fever-reducing effects by interfering with prostaglandins.
Four of the five answers listed below are potentially toxic waste products of metabolism. Select the exception.
a. urea
b. water
c. uric acid
d. carbon dioxide
e. ammonia
What are the functions of the nephron?
filtration, excretion, reabsorption, secretion
What are the results of ADH (antidiuretic hormone) secretion
water is reabsorbed in the distal tubule, fluid volume of blood increases, distal tubule and collecting duct become more permeable to water reabsorption, solute concentrations decrease in blood
What are some responses to cold temperatures?
vasoconstriction of peripheral blood vessels, uncontrolled muscular contraction, messages sent by the thermoreceptors to the hypothalamus, increased metabolic reactions
What are some responses of the body to heat?
increased sweating, decreased rate of muscle activity, increased water loss, dilation of peripheral blood vessels
What are some responses to the loss of body heat.
blood routed to deeper tissues, constriction of peripheral blood vessels, increased respiration, increased metabolic rates