Chapter 1

Question 1

Homeostasis

Answer 1

• maintenance of relatively stable internal environment
• critical variables
  
  • environmental factors that affect cells
  • material for cells needs
  • factors cells use to communicate with one another
• regulated within a range of values, not a single value
• disease state or pathological condition
  
  • failure to maintain homeostasis
  • study of body functions in a disease state is called pathophysiology
  • ex: diabetes mellitus - abnormally high blood glucose

Question 2

Negative feedback loops

Answer 2

• wants to get you back to normal
• ex: shivering = muscle contract =make you warmer
• most common
• aids in maintaining homeostasis
• cannot prevent initial disturbance
• homeostatic (stabilize variable)

Question 3

Positive feedback loop

Answer 3

• L & D = contractions = releases oxytocin
• more oxytocin = more contractions
• getting bigger and bigger
• sends regulated variable even farther from its normal value
• not homeostatic (reinforce)

Question 4

Plasma

Answer 4

• fluid component of blood

Question 5

Dynamic steady state

Answer 5

• materials are constantly moving between two compartments
• but no net movement btw the compartments

Question 6

Equilibrium

Answer 6

• implies composition of compartments are identical
• but not the same as steady state

Question 7

What does homeostasis attempt to maintain?

Answer 7

• Dynamic steady state
• disequilibrium

Question 8

Control systems

Answer 8

• local and reflex
• input signal
• integrating center
• output signal

Question 9

Regulated variables are kept within what?

Answer 9

• normal range by control mechanisms
• keeps near setpoint or optimum value

Question 10

What is local control restricted to?

Answer 10

• a tissue or cell

Question 11

Reflex control uses long-distance signaling with what?

Answer 11

• response loop
• uses nervous and/or endocrine systems

Question 12

What do response loops begin with?

Answer 12

• a stimulus

Question 13

Feedback loops modulate the response loop

Answer 13

• stimulus, sensor, input signal, integrating center, output signal, target, response

Question 14

Feedforward control allows the body to what?

Answer 14

• anticipate change

Question 15

A simple control system

Answer 15

• input signal
• integrating center (brain)
• output signal (ex: contract muscles, etc.)
• response