Acute Stress Response Pathways

The body's response to acute stress involves two major pathways that work in concert to help organisms cope with stressors and maintain homeostasis.

Definition: Acute stress response is the body's immediate reaction to perceived threats or challenges through neural and hormonal mechanisms.

The rapid nervous pathway involves:

• Immediate activation of the sympathetic nervous system
• Release of adrenaline from the medulla of adrenal glands
• Quick physiological responses including increased heart rate and breathing

Vocabulary: Medulla - The inner portion of the adrenal gland that produces adrenaline and noradrenaline.

The slower hormonal pathway includes:

• Activation of the hypothalamic-pituitary-adrenal (HPA) axis
• Release of CRH from hypothalamus triggering ACTH from pituitary
• Cortisol secretion from adrenal cortex

Example: When facing an exam (stressor), the body first responds with increased alertness and heart rate (rapid response) followed by sustained cortisol release (adaptive response).

Highlight: The system includes negative feedback mechanisms that help restore balance and build resilience after the stressful event has passed.

Common stress triggers include:

• Physical stressors: illness, injury
• Environmental factors: noise, tobacco
• Psychological challenges: examinations

The response affects multiple physiological parameters:

• Blood glucose levels
• Immune system function
• Cardiovascular activity
• Respiratory rate