Lecture 2 Flashcards
(58 cards)
What is homeostasis?
A state of equilibrium; maintenance of relatively stable internal conditions despite continuous changes in environment
Examples of homeostasis
-body temperature
-blood levels of calcium, sodium, glucose, etc
-blood pressure
-water balance/hydration
What are the components of a control mechanism?
- receptor
- control center
- effector
What does the receptor do?
The receptor is the sensor, which monitors the environment and responds to stimuli
What does the control center do?
The control center determines a set point at which variable is maintained, and receives input from the receptor. From there it determines appropriate response.
What does the effector do?
The effector receives output from the control center and provides the mean to respond.
What is the order of the control system?
- stimulus
- receptor
- input
- output
- response
What does the stimulus do?
produces change in variable
What does the receptor do?
detects change
What is the input?
information sent along afferent pathway to control center
What is the output?
information sent along efferent pathway to effector
What is the response?
The response of the effector feeds back to reduce the effect of stimulus and returns variable to homeostatic level
Negative feedback
reduces or shuts off original stimulus; variable changes in opposite direction of initial change
Positive feedback
increases original stimulus if negative feedback is overwhelmed
Ventral
toward or at the front of the body
Dorsal
toward or at the back of the body
Intermediate
between a more medial and a more lateral structure
Proximal
closer to the origin of the body
Distal
farther from the origin of the body
The lungs are ____ to the skin.
deep
The elbow is ________ to the wrist.
proximal
The skin is ___________ to the skeletal muscles.
superficial
The knee is ______ to the thigh.
distal
The heart is ______ to the arm.
medial
