Chapter 1: The Human Body: An Orientation (pgs. 8-11)

Question 1

homeostasis

Answer 1

body’s ability to maintain relatively stable internal conditions in a continuously changing outside world
dynamic equilibrium

Question 2

variable

Answer 2

factor or event being regulated

Question 3

receptor

Answer 3

first component of homeostatic control mechanism
sensor that monitors the environment and responds to changes (stimuli) by sending information (input) to the control center

Question 4

stimuli

Answer 4

changes in the environment

Question 5

control center

Answer 5

second component of homeostatic control mechanism
receives input from the receptor through the afferent pathway and determines the set point and the appropriate response to the input
output then flows to the effector through the efferent pathway

Question 6

afferent pathway

Answer 6

input from receptor to the control center

Question 7

set point

Answer 7

level or range at which a variable is to be maintained

Question 8

effector

Answer 8

third component of homeostatic control mechanism
receives output of control center through efferent pathway and provides means for the control center’s response to the stimulus
results of response feeds back to influence effect of stimulus

Question 9

negative feedback mechanisms

Answer 9

most homeostatic control mechanisms
output shuts off the original effect of the stimulus or reduces its intensity
variable changes in a direction opposite of the initial change

Question 10

positive feedback mechanisms

Answer 10

result or response enhances original stimulus so that the response is accelerated
change results in the same direction of the initial change
control infrequent events that do not require continuous adjustments (ex: childbirth, blood clotting)

Question 11

homeostatic imbalance

Answer 11

disease regarded as a result of disturbance in homeostasis

result of aging, body control systems become less efficient and internal environment becomes less stable