TASK 7 Flashcards
_homeostasis
– active process of maintaining a particular physiological parameter relatively constant _alterations in this process can effect motivation
_obligatory losses
– require us to gain and conserve heat, water, and food constantly because we involuntarily loss energy, water, or temperature as a consequence of life processes
_ingestive behaviour
– Eating or drinking.
_system variable
– A variable that is controlled by a regulatory mechanism, for example, temperature in a heating system.
_set point
– The optimal value of the system variable in a regulatory mechanism.
_detector
– In a regulatory process, a mechanism that signals when the system variable deviates from its set point.
_correctional mechanism
– In a regulatory process, the mechanism that is capable of changing the value of the system variable.
_negative feedback
– A process whereby the effect produced by an action serves to diminish or terminate that action; a characteristic of regulatory systems.
_satiety mechanism
– A brain mechanism that causes cessation of hunger or thirst, produced by adequate and available supplies of nutrients or water.
_intracellular compartment
– fluid that exists within the cells
_extracellular compartment
– fluid that exists outside the cells, acts as a buffer and as an indicator of conditions in the intracellular compartment (it constantly controls if we need water) _interstitial fluid – fluid between the cells _blood plasma – the protein-rich fluid that carries red and white blood cells
_aquaporins
– channels in the cell membranes that are specialized for conducting water molecules into or out of the cell (a single channel can conduct 3billion molecules of water per second)
_intravascular fluid
– The fluid found within the blood vessels.
_Hypovolemia
– Reduction in the volume of the intravascular fluid.
_diffusion
Movements of water described by two forces , DIFFUSION AND OSMOSIS– molecules of a substance like salt (a solute) dissolved in a quantity of another substance, such as a glass of water (a solvent) will passively SPREAD through the water because of the random movements of the molecules until they are more or less uniformly distributed throughout the glass
_osmosis
– movement of water molecules that occurs when a semipermeable membrane separates solutions containing different concentrations of solute, and the solute cannot spread itself evenly across both sides (membrane blocks passage of salt) _osmotic pressure _osmolality
_osmotic pressure
– physical force that pushes or pulls water across the membrane
_osmolality
– number of solute particles per unit volume of solvent
_hypertonic
– high concentration of salt that is the same as that found in interstitial fluid and blood plasma (about 0.9% salt)
_isotonic
– concentration of salt that is the same as that found in interstitial fluid and blood plasma (about 0.9% salt)
_hypotonic
– low concentration of salt that is the same as hat found in interstitial fluid and blood plasma (about 0.9% salt)
_osmotic thirst
– high extracellular concentration of solute (as salt), triggered by increased saltiness of the extracellular fluid – like by ingesting lots of salty foods. Water will be pulled out of cells through osmosis. SALT IS CRUCIAL FOR FLUID BALANCE
_osmosensory neurons
– specialized neuron that measures the movement of water into and out of cells because they are stretchy (they easily shrink and stretch). They’re found in several regions of the hypothalamus, including the preoptic area, anterior hypothalamus, the supraoptic nucleus, and the organum vasculosum of the lamina terminalis
_osmoreceptor
– A neuron that detects changes in the solute concentration of the interstitial fluid that surrounds it
