Desmond sees an attractive woman whom he would like to meet. As he approaches her, his heart starts racing and his pupils dilate. In this situation, is the stressor, and is the stress.

Stressor and Stress

Explanation:

In this situation,approaching the attractive woman is stressor and Desmond's racing heart is the stressStressor may be defined as any agent(chemical or biological),environmental stimulus,event or experience which may induce stress in an individualThey may induce some change:physically or psychologicallyStress is defined as a pain which gives a feeling of strain and pressureStress may include any physical,mental or emotional factorStress may be external or internalExternal stress may arise due to environmental,psychological or social situation whereas internal stress may arise due to illness or any medical procedureIn case of Desmond attractive woman acted as a stimulus and approaching her was the stressor as a result his heart started racing(external stress)

Approaching the attractive woman; Desmond's racing heart

Explanation:

Desmond sees an attractive woman whom he would like to meet,  His heart start racing and his pupils dilate, as he start to approaching that woman.

In these conditions, approaching the attractive woman is the stressor because approaching the woman causes heart beat racing and pupil dilate, and  Desmond's racing heart is the stress because it occurs in the response of stressor.