Study Guide: Stress Response Systems

Study Guide (2023) Intro to stress: Review the **first two weeks slides** plus **quizzes 1&2**. Know reasons for the - human stress response system, - the function of the stress system, - various ways of viewing the response system by discipline and perspective, - some of the histo...

Study Guide (2023) Intro to stress: Review the **first two weeks slides** plus **quizzes 1&2**. Know reasons for the - human stress response system, - the function of the stress system, - various ways of viewing the response system by discipline and perspective, - some of the historical figures in stress, - the different kinds of stressors and different types of stress (acute, eustress, toxic, etc.). Understand basics of how stress is measured and why, and some of the terms associated with stress and **homeostasis** (e.g., **supporting action, arousal, vigilance, regeneration, etc.).** - Know the basics of **biofeedback** and **how related to stress** [(e.g., what is it measuring?] [In the case of thermometer types, it is temperature and why?]). - What are stress surveys trying to do? How can they be useful? A & P Stress response systems: The three systems involved in the stress response are: - The Nervous System - The Neuroendocrine System - The Immune System **Nervous System Terms:** 1. **C**entral **N**ervous **S**ystem: (CNS) Consists of the brain and the spinal cord. Controls both voluntary and involuntary functions of our body. 2. The Brain: The central control system for humans. There are 3 levels of function a. [The lowest level of function:] (sometimes called your reptilian brain). These are your automatic responses, and these responses are executed by the ANS b. [The Limbic system:] This system matches your automatic system to your emotional centers. This system allows you to interpret your automatic system responses c. [The Neocortical level]: This system Allows you to think about a response and decide to act in a different way. The **Neocortex** (the forebrain) Processing of the sensory information (decoding) then conscious thought processing can occur and through thought processing the organism can influence emotional and voluntary responses. **Axon/cell body:** nucleus and long connector to the axon terminals. Axon terminals connect to dendrites of other neurons. **Dendrites:** The part of the neuron that the cell uses to connect to other neurons **Myelin Sheath:** A fatty layer that wraps around the nerve fibers. This causes the conduction velocity to increase 3. Brain stem: Area of the brain responsible for survival. Autonomic functions are controlled by this structure. Consists of the mid brain and hind brain structures (Medulla, Pons, Cerebellum) 4. Peripheral Nervous System: (PNS) Connects the limbs and the trunk to the CNS. It is responsible for moving CNS information to the limbs and from the limbs back to the CNS. It allows the body to respond to the environment. 5. Autonomic Nervous System: (ANS) It is the branch of the peripheral nervous system responsible for involuntary responses. The ANS has two branches: The sympathetic and parasympathetic nervous systems. 6. The Sympathetic Nervous System (SNS): The go system. This system activates the stress response. (Fight or Flight) 7. The Parasympathetic Nervous System (ParaNS): The brake system. The lifting of the brake on the SNS causes an immediate stress response. (Rest and Digest) 8. The Reticular Activating System: (RAS) located in the brain stem and mostly in the pons. It is responsible for the arousal of the body so it has a major influence in the stress response. A major nucleus in the RAS under SAM (sympathetic adrenal medullary) control is the Locus Correleous. Information from here ascends (goes up) to the Thalamus (a sensory relay system) and the Hypothalamus (the center that causes homeostasis and many types of behaviors. The information then continues to the cerebral frontal cortex (where you think and plan). Information then descends (goes down) to the cerebellum and the sensory/cranial nerves 9. Limbic system: The emotional center of the brain. Consists of the following midbrain structures: d. Thalamus (the sensory relay center) e. The Hypothalamus (a behavioral center) f. The Hippocampus (a memory center) g. The Amygdala (the arousal or alarm center) h. The Pituitary gland (the connection to the endocrine system, sometimes called the master gland) 10\. The insula and relevance to Limbic system Terms: 1. Allostasis: The physiological and psychological responses to a stressor. Mediated through the Sympathetic Nervous system (SNS). Remember the SNS increases the physiological response such as Heart and Respiration rate and diverts energy away from digestion. 2. Homeostasis: The resting or neutral physiological or psychological state. Mediated by the Parasympathetic Nervous System (PNS) Although these systems have different effects, they work together to regulate stress physiology. At any given moment one system is more active than the other. Remember the activation of these systems is controlled by the person's perception of their environment and their appraisal of resources they have to manage or control. 3. Catecholamines: Produced as the initial responses to a stressor. Important ones are Epinephrine, Norepinephrine and Dopamine. Their purpose is to begin the stress response, supply an initial burst of energy and increased blood flow to skeletal muscle. Corticosteroids: Also called glucocorticoids. Cortisol sustains the stress response. Cortisol: A glucocorticoid that creates energy needed by the body for the sustained stress response. It is regulated by a negative feedback system. Measured in blood, urine, saliva and hair. Negative feedback: A system that tells the pituitary and the hypothalamus that there is enough Cortisol in the body and stops production of excess cortisol. Normal system. Built this was because cortisol can be toxic if levels are too high. Cortisol: Released from the Adrenal cortex and is responsible for producing the sustained stress response. Cortisol has a normal rhythm of production by your body. Has a day-night cycle or pattern of production that is similar across all humans. Production spikes just 30 min. after you wake up and declines during the day. There are repeated spikes after food intake during the day. Chronic stress can impair normal daily rhythms and overtime this can impact functional performance. 4. Acetylcholine: The primary neurotransmitter that begins the Parasympathetic Response. It is produced when the threat or stressor is removed. 5. The Vagus Nerve: 12th cranial nerve. It is the longest cranial nerve and only one that leaves the head/neck and travels the length of the abdomen. It connection to many target organs and is responsible for responses of those organs. It is associated with the parasympathetic response. 6. Synapse: The term used to describe a connection between two nerves. 7. Sympathetic Ganglia: A chain like structure located just outside of the spinal cord from the thoracic and lumbar section or the spinal cord. They are relays that speed neural impulses to their target organs (heart, stomach, lungs etc.) and the chain is located close to the spinal cord. 8. Pre-ganglionic nerves: Nerves that leave the spinal cord and synapse to ganglia. 9. Post-ganglionic nerves: Nerves that leave the ganglia and synapse with another nerve or target organ. 10. How does the brain communicate to the body's structures? a. Directly to allow for immediate responses through nerves (hard-wired) b. Indirectly through hormones (chemical transmission) for sustained responses. 11. The Endocrine System: A network of glands that release hormones (chemicals) into circulation. These hormones tell target organs what to do. This system is activated by the stress response and is how the sustained response occurs. The major endocrine glands involved in the stress response are: c. The Pituitary Gland d. The Adrenal Gland e. The Pineal Gland f. The Thyroid Gland Components of the Endocrine System: Glands (structures that respond to a release hormones), Blood circulation (hormones are transported by the circulation system, Hormones: chemicals that direct target organs to activate and function, Target organs are the structures that respond to hormones and control bodily (physiological) functions. The stress response occurs through three forms of response or "arms": A short arm or immediate response an intermediate in-between response and a long arm or sustained response and. 12. The Short Arm Response (Sympathetic-Adrenal Medullary or SAM): There is a stressor and you release the catecholamine's. As this happens an important nucleus in the Reticular Activating System (RAS) (locus coeruleus) is stimulated. This causes the ANS to go into high gear as the sympathetic neurons go directly to the target organs. At the same time the Hypothalamus is stimulated to release a hormone (CRH) and send it to the pituitary gland which sends ACTH. The adrenals receive ACTH In the adrenal cortex and produce cortisol. This is the sustained Long Arm response through the Endocrine system. 13. The Long Arm Response: g. 1.Mediated primarily through the HPA (Hypothalamus-Pituitary-Adrenal) Axis. The hypothalamus releases Corticotrophin-releasing Hormone (CRH) which stimulates the pituitary gland to release Adreno-corticotrophin releasing hormone (ACTH) which will stimulate the adrenal gland cortex and cause the release of Cortisol. b\. Thyroxine Axis: Hypothalamus\>Pituitary\>Thyroid c\. Vasopressin Axis. -- blood pressure, water retention Vasopressin Axis: Another system that is part of the endocrine system. This system is responsible for retaining water and regulates blood pressure. It is activated by the hypothalamus which signals the pituitary gland to release Vasopressin (ADH Other Stress-related Hormones Oxytocin: Released by the Pituitary gland. Associated with lactation and childbearing. Triggered by feelings of love and affection. Role as a cortisol modifier. Dopamine: Released during the SAM response. Increases HR and is associated with pleasurable feelings Endorphins: A neural transmitter/hormone associated with good stress and pain relief. Acts as an naturally produced opioid pain reliever. DHEA: Can block cortisol receptors (stress modifier) and may have an antidepressant effect. Serotonin: Neurotransmitter/hormone associated with a positive mood. Most is produced in the digestive tract.