Intro to Physiology (Flashcards)
What is physiology?
The study of how the body functions, including the physical and chemical processes in cells, tissues, organs, and organ systems that allow them to work individually and together to sustain life
What is homeostasis?
The ability to maintain relatively stable conditions in the internal environment, despite changes in the external environment. Cells can only survive within a narrow range of conditions, so body conditions must be maintained within physiological limits. Disease is a failure to maintain homeostasis
Which systems control all other systems to maintain homeostasis?
The nervous and/or endocrine systems
What are some examples of conditions controlled by homeostasis?
pH, temperature, blood gases (CO2, O2), blood pressure, intracellular and extracellular fluid volumes, and many more
What are the two main types of nervous/endocrine responses?
Anticipatory responses and feedback mechanisms.
What are the three basic components of feedback mechanisms?
Receptors, control areas, and effectors
What is the role of receptors in feedback mechanisms?
Receptors monitor variables/condition
What is the role of control centers in feedback mechanisms?
Control centers integrate information and maintain setpoints by signaling to effectors
What is a setpoint?
A range of values of a variable that do not bring about a response (i.e., “normal range”)
What is the role of effectors in feedback mechanisms?
Effectors create a response that will alter the variable/condition
What is negative feedback?
A common homeostatic control mechanism where the result of the “output” causes the variable to move back toward the set point, in the opposite direction to the change that triggered the response
Give an example of negative feedback related to body temperature.
If body temperature increases, blood vessels dilate and sweat evaporates, resulting in increased heat loss and a decrease in body temperature. Conversely, if body temperature decreases, shivering occurs, leading to an increase in body temperature.
What is positive feedback?
A less common, non-homeostatic process where the output of the feedback intensifies the input, causing the variable to move further away from the set point
Give an example of positive feedback.
Childbirth, where labor continues until the baby is born
