All but which of the following are significant routes for water loss from the body?
a. excretion in urine
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?
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?
What is the last portion of the excretory system through which urine passes before it is voided from the body?
After the blood leaves the glomerular capillaries, it goes via the efferent arterioles to what kind of capillaries?
What is the process called during which potassium and hydrogen ions, penicillin, and some toxic substances are put into the urine by active transport?
Which of the following processes is under voluntary control?
Which of the following substances is NOT filtered from the bloodstream?
b. plasma proteins
What is the name given to the fluid removed from the blood but not yet processed by the nephron tubules?
Reabsorption is the movement of water and solutes from the __________ to the __________.
nephron tubules; capillaries
What amount of the fluid removed from the blood is eventually returned to the blood?
greater than 98 percent
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?
Which of the following is actively transported in the proximal tubules of the kidney?
a. bicarbonate ions
b. sodium ions
c. chloride ions
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
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.
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.
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 are responses to low temperature that increase the chance for survival?
shivering, production of brown fat, pilomotor response, increased metabolism
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.
c. uric acid
d. carbon dioxide
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