Physiologic response to stress

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Questions and Answers

What type of response does the hypothalamus coordinate during stress?

A long-term behavioral response

A purely emotional response

A rapid autonomic and slower endocrine response (correct)

A decentralized response

What is the role of cortisol in the physiological response to stress?

Facilitating longer-term adaptation to stress (correct)

Providing immediate energy for muscles

Reducing heart rate during stress

Initiating emotional responses

Which part of the nervous system is primarily involved in the rapid response to stress?

Central nervous system

Parasympathetic nervous system

Sympathetic nervous system (correct)

Peripheral nervous system

What term describes the body's adaptive state when responding to environmental stressors?

Allostasis Signup and view all the answers

Which system is responsible for the slower, chronic responses to stress?

Endocrine system Signup and view all the answers

What is the primary role of the hypothalamus in stress response?

Coordinating output from the nervous system and pituitary glands Signup and view all the answers

What does the concept of allostasis refer to?

Physiologic changes in response to challenges to homeostasis Signup and view all the answers

Which system is primarily involved in the physiological response to stress?

Autonomic nervous system and endocrine system Signup and view all the answers

How does perception of stressors influence stress response?

It significantly impacts the response and outcomes of stress Signup and view all the answers

What does allostatic load measure?

The cumulative effects of stress on an individual's health Signup and view all the answers

Which receptors are primarily involved in the sympathetic innervation of the heart?

β1-receptors Signup and view all the answers

What is the effect of the parasympathetic nervous system on the heart's nodes?

Inhibits electrical conduction in both SA and AV nodes Signup and view all the answers

Which part of the heart does the sympathetic nervous system NOT innervate?

Ventricular valves Signup and view all the answers

What neurotransmitter is released by the sympathetic nervous system to act on the heart?

Norepinephrine Signup and view all the answers

In a resting human, which system is primarily active in regulating heart rate?

Parasympathetic nervous system Signup and view all the answers

Which statement is true regarding an isolated human heart?

It maintains a constant heart rate of approximately 100 beats per minute Signup and view all the answers

Which of the following structures receives innervation from both the sympathetic and parasympathetic nervous systems?

SA node Signup and view all the answers

What impact does the activation of β1-receptors have on the myocardium?

Increases contractility Signup and view all the answers

If the parasympathetic nervous system is stimulated, what would be expected to happen to the heart rate?

Heart rate would decrease Signup and view all the answers

What is the heart rate at rest due to the dominant parasympathetic activity?

70 beats/min Signup and view all the answers

What effect does inspiration have on heart rate during respiratory sinus arrhythmia?

Heart rate increases Signup and view all the answers

What is the heart rate during expiration recorded in the experiment?

75 beats/min Signup and view all the answers

Which reflex mechanism is primarily responsible for the increase in heart rate during inspiration?

Bainbridge reflex Signup and view all the answers

What might the absence of respiratory variations in heart rate indicate in patients?

Autonomic dysfunction Signup and view all the answers

What happens to heart rate during the cardiac dive response when a person is submerged in ice-cold water?

It decreases significantly Signup and view all the answers

What is the heart rate on inspiration as recorded in the figure?

88 beats/min Signup and view all the answers

What is one of the consequences of respiratory sinus arrhythmia for gaseous exchange in the lungs?

Enhances blood flow during inspiration Signup and view all the answers

What is the total resting heart rate when both sympathetic and parasympathetic activities are accounted for?

100 beats/min Signup and view all the answers

What physiological role does the Bainbridge reflex serve during inspiration?

Prevents blood pooling on the venous side Signup and view all the answers

Study Notes

Physiological Response to Stress

Stressors can be physical or psychological, internal or external
The body's perception and processing of stressors significantly impacts the response
The stress response is designed for rapid return to a stable state for survival
Allostasis: the physiological changes (neuroendocrine, autonomic, immune) that occur in response to challenges to homeostasis.
Allostatic load: accumulation of these allostatic changes - a measure of stress effects on humans
Physiological response to stress has both rapid (acute) and slower (chronic) components
Stressors can be perceived differently resulting in varying responses

Coordinated Response to Stress

Stressors trigger a coordinated response involving the higher brain centers (hypothalamus)
The hypothalamus activates both the autonomic nervous system and the endocrine system
The autonomic nervous system triggers a fast response
The endocrine system (anterior and posterior pituitary) trigger a slower, more chronic response
The coordinated response involves the sympathetic nervous system, parasympathetic nervous system, and the endocrine system

Role of the Hypothalamus

The hypothalamus is a crucial hub in the stress response
It connects the higher brain centers, autonomic nervous system, and the endocrine system
It coordinates responses to stressors through the locus ceruleus, anterior pituitary, and the adrenal gland
It plays roles in the RAS (reticular activating system) and spinal cord signals.
The hypothalamus is the central integrator of the stress response.

Learning Objectives

Review autonomic nervous system structure and function
Explain the role of the endocrine and nervous systems in regulating organ systems
Explain the hypothalamus' role in coordinating outputs from the nervous system and pituitary glands
Explain the general neuroendocrine response to stressors
Describe the adrenal gland's role in stress response
Understand the impact of respiration on heart rate
Be aware of the mechanisms for the Bainbridge reflex.
Recognize variations in heart rate during the stress response, such as Respiratory Sinus Arrhythmia
Explain the cardiac dive response.

Stressors

Both physical and psychological factors can trigger stress
Stressors have internal and external origins
An individual's perception and processing of stressors greatly affect the outcome of the response.
The individual's perception and processing of stressors significantly impact the stress response.

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