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Anatomy and Physiology > Homeostasis > Flashcards

Flashcards in Homeostasis Deck (15)
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1
Q

homeostasis

A

The tendency of an organism to maintain a stable internal environment even though the external environment changes continuously.

2
Q

with proper homeostatic function, internal conditions stay within a _____ range

A

narrow

3
Q

normal arterial pH

A

7.35 - 7.45

4
Q

homeostatic control systems

A

Mechanisms that monitor the internal environment and correct as needed

5
Q

homeostasis: “local control”

A

Isolated change in a few cells or a tissue,
response emerges and acts locally.

-on the cellular level

6
Q

homeostasis: “reflex control”

A

Long-distance signaling, typically involving endocrine (hormonal) or neural responses

-organ, whole-organism level

7
Q

3 MAJOR components of homeostatic control systems

A
  1. input signal
  2. integrator (controller)
  3. output
8
Q

state the order of the response loop

A
  1. stimulus (change in internal environment)
  2. sensor (receptor, detects change, conveys info)
  3. input signal (afferent neuron)
  4. integrator (controller)
  5. output signal (hormone, neuron)
  6. target effector (muscle, gland, etc.)
  7. response (change corrected)
9
Q

function of “integrators”

A

control center

  • posses a “set point” within a normal range
  • look for error signals in the input

(hypothalamus, kidney)

10
Q

fever

A

thermostat in brain increases set point for core body temp

11
Q

acclimitization

A

adapting to certain conditions

-having more red blood cells when living in a higher altitude

12
Q

negative feedback

A
  • turns OFF response loop
  • exerts control
  • homeostasis
  • self terminating
  • prevent changes
  • acts to oppose input
13
Q

positive feedback

A
  • turns ON response loop
  • amplify changes
  • no control
  • not self terminating, need outside factor to shut them off
14
Q

give an example of a negative feedback loop

A

glucose homeostasis

  • insulin (lowers blood glucose levels)
  • glucagon (raises blood glucose levels)
  • opposite actions of these hormones maintain glucose homeostasis in the body
  • also body temp
  • blood pressure regulation
15
Q

how are uterine contractions and lactation examples of a positive feedback loops?

A

non-self terminating
amplify effects

-more oxytocin release triggered by suckling/baby dropping in uterus amplifies the effects of lactation/uterine contractions