Lecture 1--Homeostasis Flashcards
2025--Dr. Cook
Response reinforces stimulus
Positive feedback loop
Describe positive feedback loop….and provide a few examples
–NOT homeostatic
–One direction
–can result in instability and disease
–response reinforces stimulus*
–ex: severe hemorrhage (less effective pumping), child birth, coagulation
Feedback Loop that can result in instability and disease
Positive Feedback loop
Feedback Control anticipating change….provide example
Feedforward….Insulin secretion at the thought of food
Feedback control considered Homeostatic
Negative Feedback Loop
Feedback control promoting stability (but not static)
Negative Feedback Loop
Primary control of homeostasis
Negative Feedback Loop
process of maintaining a “steady state” between differing environments (ex: extracellular vs intracellular)
Homeostasis
Homeostasis is largely accomplished through ____
reflexes
(homeostasis) the variable typically has a ____ in which dif physiology mechanisms maintain a “steady state”. not considered equilibrium..many homeostatic mech maintain a disequilibrium
Setpoint
T/F: A Steady State does not need energy to maintain, Equilibrium does
False; Equilibrium does not need energy to maintain, a steady state does
Homeostasis requires ___ and ___
1) energy to maintain 2) time..hours at a time
T/F Homeostasis is a static process
False..not a static process
it is a stable process
_______ helps maintain physiological variable with a range
Negative Feedback
Name the system involved in systemic feedback based on the info:
–very specific (signal directly to target)
–very fast
Nervous System
Name the system involved in systemic feedback based on the info:
–Uses chemical and electrical signals
–short-term responses
Nervous System
Name the system involved in systemic feedback based on the info:
–Higher frequencies= stronger signal
Nervous System
Name the system involved in systemic feedback based on the info:
–more general (signal released into bloodstream)
–more hormone=stronger signal
–uses chemical signals
Endocrine System
Name the system involved in systemic feedback based on the info:
–slower speed
–long-term responses
Endocrine System
T/F: Systemic involves more than 1 organ system
True
Systemic Feedback primarily uses the ___ and ____ systems to coordinate responses
nervous and endocrine
Cardiovascular system (cardiac output) and brain (blood glucose) maintenance are examples of _______
Systemic (homeostasis)
–additional example is vasoconstriction
Homeostasis restricted to level of organ, tissue, or cell
Local
(Homeostasis Type)
utilizies paracrine, contact dependent, and autocrine signaling
Local
Peptide induced acid secretion in the stomach, and up/down regulation of membrane transporters. as well as inc CO2 leading to vasodilation are examples of:
Local homeostasis
–sometimes can override systemic!
Homeostasis goal is to balance ____
net gain/net loss
(Parts of reflex pathway)
perceived by the body, Threshold
stimulus
(Parts of reflex pathway)
detects the stimulus at a given threshold (cells, membrane receptors, etc.)
Receptor
(Parts of reflex pathway)
transmits receptor info towards integrating center
Afferent Pathway
(Parts of reflex pathway)
analyzes information based on setpoint, formulates response–Typically CNS or Endocrine Gland.
Integrating Center
(Parts of reflex pathway)
CNS sends motor commands; endo secretes hormones
Efferent Pathway
(Parts of reflex pathway)
Target cell, tissue, and/or organ
Effector
(Parts of reflex pathway)
Local and/or systemic
Response
Body Temp regulation is an example of a systemic homeostasis response mediated by ___
Nervous system
2 Effector Control Patterns
1) Tonic Control
2) Antagonist Control
(Effector Control Patterns)
–Always basal level of activity
–Rheostat control (control of your furnace)
Tonic Control
(Effector Control Patterns)
–effector controlled by 2 or more pathways
–pathways oppose each other
–each individual path has tonic “like” control
–when “X” signal high, “Y” signal low
Antagonist Control
Provide an example of a mechanistic explanation for the fact that blood flows:
(How?)– a driving pressure is created to provide the potential to overcome resistance to flow resulting in blood moving from high to low pressure
Provide an example of a teleological explanation for the fact that blood flows:
(Why?)– to deliver Oxygen and other nutrients, and transport wastes away from metabolically active tissues/cells
