Chapter 2: Control of the Internal System Flashcards
homeostasis
maintenance of a relatively constant internal environment
- denotes a relatively stable internal environment during resting conditions
steady state
this means a physiological variable is constant and unchanging
how do homeostasis and steady state differ
ex. body core temp when working out. Your core temp plateus at about 40 minutes becoming the new steady state but the homeostatic number is when it is at rest
control systems of the body
overall goal is to keep physio variable at or near constant value
- most intricate is inside cells to maintain protein breakdown & synthesis, energy production, and appropriate stored nutrient amount
what are the (3) parts of a biological control system
- sensor (receptor)
- control center
- effectors
define negative feedback loop
the resulting loop decreases the original stimulus
define positive feedback loop
act to increase the original stimulus.
ex: birth
define gain of a control system
precision to maintain homeostasis. the “capability” of the system.
if very capable = high gain value
what is the mathematically way to determine gain
correction/error
a system with large gain would have a large magnitude of correction and after this is achieved limited error would exist
examples of large gain systems in body
body temperature, breathing, delivery of blood
what is the purpose of hormones
aid to regulate circulatory and metabolic functions from eight endocrine glands
what part of a feed back loop (receptor, control center, effector) is not working properly in diabetes 1
effectors (beta cell of pancreas does not produce insulin)
what conditions are hardest to maintain homeostasis when exercising
intense, prolonged, hot, or humid
define adaptation
improved ability to maintain homeostasis through changes in structure or function of cells and organ systems
hormesis
beneficial response to low dose of stress but harmful at high doses related to exercise induced adaptation in cells
cell signaling
communication between cells to coordinate cellular activities that allows improved ability to maintain homeostasis
acclimation
improved function of an existing homeostatic system
what are the five cell signaling mechanisms: intracrine
chemical messenger produced in a cell causes a pathway within the same cell leading to specific response
juxtacrine signaling
one cell comes into contact with another and the small junctions of the cytoplasm connect
autocrine
releases chemical messenger in extracellular fluid that acts upon same cell.
autocrine example
while resistance training in muscle cell triggers DNA to produce more contractile protein to increase size of muscle cell.
paracrine signaling
chemical messengers act on nearby cells
endocrine
release chemical signals (hormones) into blood to transport throughout body.
- usually response cell is only those with specific receptor for the hormone
cellular stress response
create stress proteins to stop damage to cells from stress (low pH or free redicals)
