Positive feedback differs from negative feedback in that

Positive feedback differs from negative feedback in that

A) the effector's response increases some parameter (such as body temperature), whereas in negative feedback it can only decrease the parameter.
B) positive feedback benefits the organism, whereas negative feedback is detrimental.
C) the positive feedback's effector responses are in the same direction as the initiating stimulus rather than opposite to it.
D) positive feedback systems have only effectors, whereas negative feedback systems have only receptors.
E) positive feedback systems have control centers that are lacking in negative feedback systems.


Answer: C

Which process in the nephron is least selective?

Which process in the nephron is least selective? 

A) reabsorption
B) active transport
C) secretion
D) salt pumping by the loop of Henle
E) filtration


Answer: E

Connective tissues typically have

Connective tissues typically have 

A) many densely packed cells with direct connections between the membranes of adjacent cells.
B) a supporting material such as chondroitin sulfate.
C) relatively few cells and a large amount of extracellular matrix.
D) the ability to transmit electrochemical impulses.
E) the ability to shorten upon stimulation.


Answer: C

Antidiuretic hormone (ADH) functions at the cellular level by

Antidiuretic hormone (ADH) functions at the cellular level by 

A) causing an increase in the number of aquaporin molecules of collecting duct cells.
B) decreasing the speed at which filtrate flows through the nephron, leading to increased reabsorption of water.
C) triggering the synthesis of an enzyme that makes the phospholipid bilayer more permeable to water.
D) causing membranes to include more phospholipids that have unsaturated fatty acids.
E) stimulating the reabsorption of glucose through channel proteins.


Answer: A

Low selectivity of solute movement is a characteristic of

Low selectivity of solute movement is a characteristic of 

A) filtration from the glomerular capillaries.
B) H+ pumping to control pH.
C) secretion along the distal tubule.
D) salt pumping to control osmolarity.
E) reabsorption mechanisms along the proximal tubule.


Answer: A

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

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

A) they are the body's only means of shedding excess nutrients.
B) they operate an extensive set of active-transport ion pumps.
C) they store the body's excess fats.
D) they have membranes of varying permeability to water.
E) they have an abundance of myogenic smooth muscle


Answer: B