Homeostasis Flashcards
Parts of the feed back loop
- Sensor
- Integrator
- Affector
In addition to water, what is lost when blood is lost?
Na+
In addition to water, what is lost with vomit?
H+
In addition to water, what is lost in diarrhea?
HCO3-
What are the 3. Things proper physiological function requires?
Isolation
Communication
Transport
What are the regulated variables of homeostasis?
Temperature
Blood Pressure
Volume
Ionic Composition
What variables are regulated at the whole body level?
Mean arterial pressure
Blood volume
Body weight
What variables are regulated at the interior milieu level?
Core body temperature
Plasma levels: O2, CO2, glucose
Plasma ion concentration: H+, Na+, K+, Ca2+, Mg2+
What variables are regulated at the cellular level?
Volume
Ion concentration: H+, Na+, K+, Ca2+, Mg+
What will a deviation in a regulated variable of homeostasis cause?
A correcting response
What is the difference between steady state and homeostasis?
Homeostasis requires ACTIVE regulation
Sensorium
Sum of the body’s sensations and perception
Transducer
Converts one form of energy to another
Simple sensory receptor
Free nerve endings
Complex sensory receptor
Encapsulated nerve ending
Exteroceptors
Receives stimuli from the outside of the body
Interoreceptors
Receives stimuli from the inside of the body
Mechanoreceptors
Sensitive to stretch, pressure, vibration
Thermoreceptors
Regulated skin and brain temp. Skin 20-40ºC, Brain 37º (±3º safety)
Chemoreceptors
Chemical stimuli. Taste/smell. CO2/H+/O2
Nociceptors
Associated with pain, respond to extreme pressure, temp, any potentially damaging stimuli
What pathway takes sensory info to the integrator?
Afferent Pathway
Error signal
The difference betweeen the actual value and the set point. The bigger the signal, the bigger the regulation. (Aka stress, perturbation, disturbance)
What happens when an error signal is amplified?
Positive feedback
What happens when the error signal signals a correcting defense?
Negative feedback
Feed-forward control
A pre-determined response to an environmental signal that does not response to feedback loops
What pathway signals the response to the stimuli?
Efferent pathway
Effects of insulin
Decrease in BG Moves glucose intracellularly Stores glucose to make glycogen Burns glucose Stores fat (triglycerides) Makes proteins
Effects of glucagon
Increases BG Increases glycogen breakdown Increase production of new glucose Protein breakdown in SK muscle Increase in lipolysis Increase in lipid oxidation
Alpha-adrenergic stimulation
Inhibits insulin secretion
Beta-adrenergic stimulation
Glycogen breakdown during exercise
Parasympathetic-cholinergic stimulation
Augments insulin secretion
Redundancy
Multiple systems mobilize to regulate a particular variable
Modulated variable
Action of a system on the responses that oppose perturbation
