Psy104 Notes

Psychopathology- the study of abnormal behaviour

Biological functions such as eating, drinking and sleeping are regulated by...

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Homeostasis: steady state of equilibrium within bodily systems. A system is returned to a resting level through motivational states that energise and direct homeostasis-restoring behaviours.

Thus, homeostatic systems include several features:

1. Set Point: biologically optimal level the system strives to maintain.

2. Feedback mechanisms: provide information regarding the state of the system with respect to variables being regulated.

3. Corrective mechanisms: restore the system to its set point when needed.

Physiological needs describe a deficient biological condition. Occur with tissue and bloodstream deficits, as from water loss, nutrient deprivation or physical injury.

➡ If water loss occurs below an optimal homeostatic level (around 2%) this creates the physiological need that underlies thirst.

THIRST is defined as a consciously experienced motivational state (drive) that readies the body to perform behaviours needed to replenish water deficit.

➡ So drive is a psychological (not biological) term. Conscious manifestation of an underlying biological need that has motivational properties (to energise and direct behaviour).

➡ How does thurst arise? Water lies inside (intracellular fluid contributes 40% body weight) and outside (extracellular fluid contributes 20% body weight) cells.

We may distinguish between osmometric (intracellular) and volumetric (extracellular) thirst.

➡ How does our body know when to stop drinking? negative feedback system...several possible locations.

Intra-Organismic Mechanisms: include all the biological regulatory systems within a person that act in concert to activate, maintain and terminate the physiological needs that underlie drive (three main categories are brain structures, endocrine system and bodily system).

Extra-Organismic Mechanisms: include all the environmental...