Homeostasis (Hamzah) Flashcards
why is homeostasis essential?
homeostasis is central to physiology which is essential for the study of medicine
evolution: ____ regulatory mechanisms, but can become? ex?
complex and robust but can become fragile in novel ecological situations: drug addiction, obesity, hypertension
complex systems possess ___ properties, which means?
emergent: sum of the parts do not constitute the whole aka it’s greater than basic anatomy and physiology
take what type of approach to physiology?
integrative: you can’t do just a reductionist investigation of component parts
4 themes in physiology
structure + function are related. energy is important for life. communication coordinates body functions. homeostasis maintains internal stability.
homeostasis: def?
a highly dynamic physiological process. life is held in equilibrium only through continual compensatory adjustment = relative stability of internal environment
what constitutes the internal enviornment
ECF: transition between outer environment and ICF inside cells
ICF is conditioned by, which is conditioned by…
ICF conditioned by intersititial fluid which is conditioned by the plasma which is conditioned by the organ systems it passes through
fluid in the body is in what type of equilibrium?
dynamic: constant exchange of fluid and solutes
distribution of fluid in body: 3 categories and volumes?
intracellular fluid 28L. plasma 3L + interstitial fluid 11L = extracellular fluid 14 L.
human body is an __ system, which means it exchanges?
open: heat and material exchanged with surrounding environment
homeostasis = equilibrium?
homeostasis isn’t equilibrium: it is the relative stability of internal environment aka extracellular fluid.
composition of ECF and ICF in what state?
dynamic steady state = material constantly moving back and forth and their compositions are not equal
two general control mechanisms for homeostasis? when are they activated?
local control. long distance reflex control. activated if variable move too far from a set point.
control system: 3 main components
input signal. integrating centre. output signal.
simplest form of control is? restricted to?
local control mechanisms: restricted to a tissue or cell
local control mechanism: what happens? response? example?
relatively isolate change in tissue = close group of cells sense change and responds, response is restricted to that region. ex: decreased O2 content in a tissue
reflex control is ____ (distance wise)? what?
long distance: wide spread changes in body aka systemic
what type of control is blood pressure?
long distance, reflex control
