Concept of homeostasis and the principle of homeostatic control systems Flashcards
(21 cards)
homeostasis
the ability of a cell or organism to regulate its internal conditions using feedback systems
feedback systems
negative, positives
Physiological range
internal environment must be maintained within narrow limits
factors homeostatically regulated (7)
- conc. of nutrient molecules
- conc. of o2 and CO2
- conc. of waste products
- pH
- conc. of water salt and other elcteolytes
- blood plasma volume and pressure
- temperatuer
Homeostatic control systems
detect deviations from normal in the internal environment that need to be held within narrow limits, integrate this info with other relevant info and make appropriate adj. to restore a factor to its desired value
2 classes of control systems
intrinsic controls and extrinsic controls
intrinsic controls
local controls that are inherent in an organ
extrinsic controls
regulatory mechanisms initiated outside and organ, accomplished by the nervous and endocrine systems
feedback loops
responses made after a change
feedforward loops
responses made in anticipation of a change
negative feedback
The primary type of homeostatic control, opposes initial change
components of negative feedback
sensor, control centre, effector
sensor
monitors magnitude of a controlled variable
control centre
compares sensor’s input with a set point
effector
makes a response to produce a desired effect
Positive feedback
amplifies and initial change, doesn’t occur as often as negative feedback (Childbirth and breast feeding
feedforward mechanisms and anticipation
anticipated a change in a regulated factor: food in digestive tract
systems involved in hormonal control of energy balance
peptide (GLP-1) Hormone (Insulin, ghrelin), Neurotransmitter (ghrelin) change in response to meal and food cues
Complexity of human eating behaviours
food intake can be complete dissociated from endogenous signaling factors
disruptions in homeostasis
can lead to illness and death
