Ch. 9 Flashcards
Chapter 9 of The Mind's Machine (79 cards)
Homeostasis
The maintenance of a relatively constant internal physiological environment
Motivation
The psychological process that induces or sustains a particular behavior
Deviations from the optimum state can affect what?
Motivation- ex. overwhelmingly powerful need to get water if you’re lost in the desert)
Thermoregulation
The active process of maintaining a relatively constant internal temperature through behavioral and physiological adjustments
Endotherms
An animal whose body temperature is regulated chiefly by internal metabolic processes (mammals). We make our own heat inside our bodies
Ectotherms
An animal whose body temperature is regulated by, and whose heat comes mainly from, the environment
Negative Feedback
The process whereby a system monitors its own output and reduces its activity when a set point is reached. The property by which some of the output of a system feeds back to reduce the effect of input signals. Ex. house thermostat
Set Point
The point of reference in a feedback system
Set Zone
The optimal range of a variable that a negative feedback system tries to maintain
How does our body use redundancy to maintain homeostasis?
Multiple redundancy (backup that protects the critical system) is a feature of many of the body’s homeostatic systems, protecting the constant internal environment that is crucial for survival
What are three kinds of temperature-regulating behavior?
- Behaviors that change exposure of the body surface (huddling or extending limbs)
- Behaviors that change external insulation (using clothes or nests)
- Behaviors that change surroundings (moving into the sun, into the shade, or into a burrow)
How does the mammalian thermoregulatory system function in general?
Receptors in the skin, body core, and hypothalamus detect temperature and transmit that information to three neural regions (spinal cord, brainstem, and hypothalamus). If the body temperature moves outside the set zone, each of these neural regions can initiate physiological and behavioral responses to return it to the set zone
Allostasis
The behavioral and physiological adjustments that maintain optimal (rather than unchanging) functioning of a regulated system in the face of changing environmental stressors
Obligatory Losses
The unavoidable expenditures of bodily resources that must then be regained from the external environment. Ex. restoring expended water
What percentage of the brain is water?
80%
Most organisms evolved homeostatic systems that ensure the composition of their body fluids closely resembles what?
Dilute Seawater
Intracellular Compartment
The fluid of the body that is contained within cells
Extracellular Compartment
The fluid of the body that exists outside the cells. Divided between the interstitial fluid (the fluid between cells) and blood plasma (the protein-rich fluid that carries red and white blood cells)
Diffusion
The spontaneous spread of molecules from an area of high concentration to an area of low concentration until a uniform solute concentration is achieved
Selectively Permeable
Also called semipermeable. A membrane that is permeable to some molecules but not other
Osmosis
The passive movement of a solvent, usually water, through a semipermeable membrane until a uniform concentration of solute (often salt) is achieved on both sides of the membrane
Osmotic Pressure
The tendency of a solvent to move across a membrane in order to equalize the concentration of solute on both sides of the membrane
Physiological Saline
A solution with a concentration of salt of about 0.9 percent. This is normally the concentration of salt in the extracellular fluid of animals. Described as isotonic.
When do cells lose water?
If the cells are surrounded by a saltier solution because the water will move out of the cell to produce uniform saltiness.