HW410 Chapter 3: “Physiology of Stress” Flashcards
What is another phrase to describe a perceived threat?
Sensory stimulus.
What is defined as a A field of study based on the principle that the mind and body are one, where thoughts and perceptions affect potentially all aspects of physiology?
Psychophysiology
What describes diseases and illnesses originating in the mind through the higher brain centers?
Psychosomatic
What are the three systems that are involved in the physiology of stress?
The nervous system, the endocrine system, and the immune system, all of which can be triggered by perceived threats.
What are the two parts of the nervous system?
The central nervous system (CNS), which consists of the brain and spinal cord, and the peripheral nervous system (PNS), comprising all neural pathways to the extremities.
What are the 3 levels of the human brain?
The vegetative level, the limbic system, and the neocortical level
What consists of the vegetative level?
Reticular formation and the brain stem.
What does the reticular formation accomplish and what do stress physiologists believe?
The reticular activating system (RAS) and its fibers connect the brain to the spinal cord.
Physiologists believe that it is the bridge joining the mind (brain) and the body as one; this organ functions as a communications link between the mind and the body
What does the brain stem consist of and what functions is it responsible for?
Pons, medulla oblongata, and mesencephalon are responsible for involuntary functions of the human body, such as heartbeat, respiration, and vasomotor activity.
It is considered the automatic-pilot control center of the brain, which assumes responsibility for keeping the vital organs and vegetative processes functioning at all times.
What is defined as it consists of the brain and spinal column, while the peripheral nervous system (PNS) comprises all neural pathways to the extremities?
Central nervous system (CNS)
What is defined as the neural fibers that link the brain to the spinal column?
Reticular activating system (RAS)
What is defined as the midlevel of the brain, including the hypothalamus and amygdala, which is thought to be responsible for emotional processing?
Limbic system. The thalmus, pituitary gland, also known as the master endocrine gland exist here.
What do the hypothalamus, thalamus, amygdala, and pituitary gland responsible for?
These four glands work in unison to maintain a level of homeostasis within the body.
What is referred to as the “seat of emotions” and controls appetite, body-core temperature and appears to be the center that registers pain and pleasure?
Hypothalamus.
What kind of anomalies might be explained because of what the hypothalamus deals with?
May explain why hunger decreases when body-core temperature increases in extreme ambient heat, or why appetite diminishes when you are extremely worried.
Explains why tempers (and violent crimes) flare up on extremely hot days during the summer months, as crime statistics prove each year.
Where does research suggest that fear is first registered in the brain?
Amygdala. the amygdala was associated with aggressive behavior (anger) as well as feelings and behavior associated with fear and anxiety.
Studies have found that the amygdala is responsible for the formation and consolidation of memories associated with events that provoked a strong emotional response (including anger and fear).
It is suggested that these memories are imprinted via the neural synapses, perhaps as an ancestral survival dynamic (e.g., beware of the rattlesnake).
Through a complicated dynamic between the amygdala and the hippocampus, specific memories of past events can reprise the fight-or-flight response, merely by thinking about them. More recent studies have also linked the amygdala to binge drinking, most likely associated with stress.
When a threat is encountered, what four specific functions does the hypothalamus carry out?
- it activates the autonomic nervous system
- it stimulates the secretion of adrenocorticotropic hormone (ACTH)
- it produces antidiuretic hormone (ADH) or vasopressin
- stimulates the thyroid gland to produce thyroxine.
What is the highest and most sophisticated level of the brain and where sensory information is processed (decoded) as a threat or a nonthreat and where cognition (thought processes) takes place?
Neocortical Level. Housed within the neocortex are the neural mechanisms allowing one to employ analysis, imagination, creativity, intuition, logic, memory, and organization. It is this highly developed area of brain tissue that is thought to separate humans from all other species.
What is important about the position of the neocortex?
The positions of these structures are such that a higher level can override a lower level of the brain. Thus, conscious thought can influence emotional response, just as conscious thought can intercede in the involuntary control of the vegetative functions to control heart rate, ventilation, and even the flow of blood.
Why is the fact about the neocortex, which deals with thought processes and decoding threats, important to recognize?
It is important to recognize when learning coping skills and relaxation techniques designed to override the stress response and facilitate physiological homeostasis.
What system works in close collaboration with the CNS and has two individual networks itself; the somatic network and ANS?
The Peripheral Nervous System (PNS)
What is the job of the somatic network?
A bidirectional circuit responsible for transmitting sensory messages along the neural pathways between the five senses and the higher brain centers.
What are the two directional pathways called?
Efferent (toward periphery) and afferent (toward brain) neural pathways.
What is defined as consisting of the sympathetic (arousal) and parasympathetic (relaxed) nervous systems. This part of the central nervous system requires no conscious thought; actions such as breathing and heart rate are programmed to function automatically?
Autonomic nervous system (ANS): Often referred to as the automatic nervous system.
The ANS regulates visceral activities and vital organs, including circulation, digestion, respiration, and temperature regulation. It received the name autonomic because this system can function without conscious thought or voluntary control, and does so most, if not all, of the time.
What did endocrinologist Bruce McEwen’s research indicate on storing stressful encounters and “brain shrinkage”?
Research conducted by endocrinologist Bruce McEwen indicates that initially a stressful encounter is etched into the memory bank (so as to avoid it down the road), but that repeated episodes of stress decrease memory by weakening hippocampal brain cells. Chronic stress is thought to wither the fragile connection between neurons in this part of the brain, resulting in “brain shrinkage.”
What is a more severe experience of a rush of fear overcoming someone?
Panic attack. Stress response on steroids. It is the response of the sympathetic nervous system. Physical symptoms of a panic attack include hyperventilation, a racing heart, sweating, chest pain, a choking feeling, nausea, chills, dizziness or feeling faint, tingling sensations, and muscle tremors or shaking.
Other symptoms include a feeling of impending death, loss of sanity, or having a “nervous breakdown.” Panic attacks are most common in early adulthood, but can occur at any age. Women are more prone to this condition than men,
Although they seem to come out of the blue, every panic attack is triggered by some decoded sensory stimuli (or memory) that creates an intense fear or apprehension about some future event. Ironically, some panic attacks are brought on by fearing another panic attack
What are the two branches of the ANS that work with the CNS to maintain a favorable homeostatic condition throughout the body? And what are they activated by?
The sympathetic and parasympathetic nervous systems, and these are activated by the hypothalamus.
How are most organs stimulated by both the sympathetic and parasympathetic systems?
Nerve Fibers.
What is defined as the branch of the central nervous system that triggers the fight-or-flight response when some element of threat is present?
Sympathetic NS
What is defined as the branch of the central nervous system that specifically calms the body through the parasympathetic response?
Parasympathetic NS
What substances are released when the sympathetic nervous system prepares the body for rapid metabolic change and physical movement?
Release of substances called catecholamines, specifically epinephrine (adrenaline) and norepinephrine (noradrenaline), at various neural synapses, a series of events occurs in several organ tissues.
What process is known in the sympathetic drive associated with energy expenditure e.g. jogging?
Catabolic functioning. A metabolic process in which metabolites are broken down for energy in preparation for, or in the process of, exercise (fight or flight).
What is epinephrine (adrenaline)?
A special neurochemical referred to as a catecholamine that is responsible for immediate physical readiness for stress including increased heart rate and blood pressure. It works in unison with norepinephrine.
What is norepinephrine (noradrenaline)?
A special neurochemical referred to as a catacholamine that is responsible for immediate physical readiness to stress including increased heart rate and blood pressure. It works in unison with epinephrine.
What physical happens to the body when epinephrine and norepinephrine are released?
Causes the acceleration of heart rate, the increase in the force of myocardial contraction, vasodilation of arteries throughout working muscles, vasoconstriction of arteries to nonworking muscles, dilation of pupils and bronchi, increased ventilation, reduction of digestive activity, released glucose from the liver, and several other functions that prepare the body to fight or flee.
What else is the sympathetic nervous system responsible for?
Supplementing the skeletal muscles with oxygen-rich blood for energy metabolism.
Which catecholamine is primary and what is the ratio released at neural synapses?
Currently it is thought that norepinephrine serves primarily to assist epinephrine, as the ratio of these two chemical substances released at neural synapses is 5:1 epinephrine to norepinephrine during the stress response.
How long does the effects of epinephrine and norepinephrine last?
Seconds. Because of their rapid release from neural endings, as well as their rapid influence on targeted organ tissue, the effects of the sympathetic nervous system are categorized as immediate.
What does the parasympathetic nervous drive? And is it referred as?
The parasympathetic drive is responsible for energy conservation and relaxation. This is referred to as anabolic functioning, during which body cells are allowed to regenerate.
What is anabolic functioning defined as?
A physiological process in which various body cells (e.g., muscle tissue) regenerate or grow.
What is the parasympathetic nervous system dominated by?
The parasympathetic nervous system is dominated by the tenth cranial, or vagus, nerve, which in turn is influenced by the brain stem.
What does the parasympathetic nervous system release, a neurological agent that decreases metabolic activity and returns the body to homeostasis?
Acetylcholine: A chemical substance released by the parasympathetic nervous system to help the body return to homeostasis from the stress response.
What is influenced by the drive of the parasympathetic nervous system?
Reduction in heart rate, ventilation, blood pressure, muscle tension, and several other functions. Both systems are partially active at all times; however, the sympathetic and parasympathetic systems are mutually exclusive in that they cannot dominate visceral activity simultaneously.
What kind of analogy can you use with cars in regards to the sympathetic and parasympathetic nervous systems?
The gas and break of a car. Sympathetic arousal, like a gas pedal pushed to the car floor, becomes the dominant force during stress, and parasympathetic tone holds influence over the body at all other times to promote homeostasis.
What are the exceptions to the dynamics of these biochemical reactions; sympathetic and parasympathetic?
For example, it is sympathetic nerves, not parasympathetic nerves, that release ACh in the sweat glands to decrease body-core temperature during arousal. And sympathetic and parasympathetic stimulation of salivary glands is not antagonistic; both influence the secretion of saliva. In addition, all blood vessels are influenced by sympathetic dominance, with the exception of the vasculature of the penis and clitoris, which is activated by parasympathetic innervation.
What are not stress hormones but they do seem to have an effect on mood?
Serotonin and melatonin. Decreases in both serotonin and melatonin are thought to be related to bouts of depression. Many things affect serotonin levels in the brain—from the natural and synthetic chemicals in the foods you eat, to the amount of sunlight you receive in the course of a day, to perhaps things we still don’t know. Research is inconclusive about how serotonin affects mood.
What is defined as a neurotransmitter that is associated with mood?
Serotonin. A decrease in serotonin levels is thought to be related to depression. The levels are affected by many factors including stress hormones and the foods you consume.
