HW410 Chapter 3: “Physiology of Stress” Flashcards
(119 cards)
1
Q
What is another phrase to describe a perceived threat?
A
Sensory stimulus.
2
Q
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?
A
Psychophysiology
3
Q
What describes diseases and illnesses originating in the mind through the higher brain centers?
A
Psychosomatic
4
Q
What are the three systems that are involved in the physiology of stress?
A
The nervous system, the endocrine system, and the immune system, all of which can be triggered by perceived threats.
5
Q
What are the two parts of the nervous system?
A
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.
6
Q
What are the 3 levels of the human brain?
A
The vegetative level, the limbic system, and the neocortical level
7
Q
What consists of the vegetative level?
A
Reticular formation and the brain stem.
8
Q
What does the reticular formation accomplish and what do stress physiologists believe?
A
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
9
Q
What does the brain stem consist of and what functions is it responsible for?
A
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.
10
Q
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?
A
Central nervous system (CNS)
11
Q
What is defined as the neural fibers that link the brain to the spinal column?
A
Reticular activating system (RAS)
12
Q
What is defined as the midlevel of the brain, including the hypothalamus and amygdala, which is thought to be responsible for emotional processing?
A
Limbic system. The thalmus, pituitary gland, also known as the master endocrine gland exist here.
13
Q
What do the hypothalamus, thalamus, amygdala, and pituitary gland responsible for?
A
These four glands work in unison to maintain a level of homeostasis within the body.
14
Q
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?
A
Hypothalamus.
15
Q
What kind of anomalies might be explained because of what the hypothalamus deals with?
A
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.
16
Q
Where does research suggest that fear is first registered in the brain?
A
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.
17
Q
When a threat is encountered, what four specific functions does the hypothalamus carry out?
A
- 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.
18
Q
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?
A
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.
19
Q
What is important about the position of the neocortex?
A
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.
20
Q
Why is the fact about the neocortex, which deals with thought processes and decoding threats, important to recognize?
A
It is important to recognize when learning coping skills and relaxation techniques designed to override the stress response and facilitate physiological homeostasis.
21
Q
What system works in close collaboration with the CNS and has two individual networks itself; the somatic network and ANS?
A
The Peripheral Nervous System (PNS)
22
Q
What is the job of the somatic network?
A
A bidirectional circuit responsible for transmitting sensory messages along the neural pathways between the five senses and the higher brain centers.
23
Q
What are the two directional pathways called?
A
Efferent (toward periphery) and afferent (toward brain) neural pathways.
24
Q
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?
A
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.
25
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.”
26
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
27
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.
28
How are most organs stimulated by both the sympathetic and parasympathetic systems?
Nerve Fibers.
29
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
30
What is defined as the branch of the central nervous system that specifically calms the body through the parasympathetic response?
Parasympathetic NS
31
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.
32
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).
33
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.
34
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.
35
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.
36
What else is the sympathetic nervous system responsible for?
Supplementing the skeletal muscles with oxygen-rich blood for energy metabolism.
37
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.
38
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.
39
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.
40
What is anabolic functioning defined as?
A physiological process in which various body cells (e.g., muscle tissue) regenerate or grow.
41
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.
42
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.
43
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.
44
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.
45
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.
46
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.
47
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.
48
What is defined as a hormone secreted in the brain that is related to sleep, mood, and perhaps several other aspects of physiology and consciousness?
Melatonin.
49
What does the endocrine system consist of?
A series of glands located throughout the body that regulate metabolic functions requiring endurance rather than speed. The endocrine system is a network of four components: glands, hormones, circulation, and target organs.
50
What are "chemical messengers" that are biochecmical created substances in the endocrine glands?
Hormones. Made up of protein compounds that are programmed to attach to specific cell receptor sites to alter (increase or decrease) cell metabolism.
51
What are the glands that are most closely involved with the stress response?
The pituitary gland and adrenal gland (most impactful in the stress response). The thyroid gland just increases the general metabolic rate.
52
What is defined as an endocrine gland (“master gland”) located below the hypothalamus that, upon command from the hypothalamus, releases ACTH and then commands the adrenal glands to secrete their stress hormones.
The pituitary gland.
53
What is defined as often called the “seat of the emotions?
The hypothalamus is involved with emotional processing. When a thought is perceived as a threat, the hypothalamus secretes a substance called corticotropin-releasing factor (CRF) to the pituitary gland to activate the fight-or-flight response.
54
What is defined as the endocrine glands that are located on top of each kidney that house and release several stress hormones including cortisol and the catecholamines epinephrine and norepinephrine?
The adrenal gland is known as “the stress gland.”
55
What are the two distinct parts of the adrenal glands that provide two very different functions?
The adrenal medulla (interior) and adrenal cortex (exterior).
56
What are the two hormones manufactured and released by the adrenal cortex and what are their functions?
It manufactures and releases corticosteroids: glucocorticoids and mineralocorticoids.
Glucocorticoids - A family of biochemical agents that includes cortisol and cortisone, produced and released from the adrenal gland. Cortisol being the primary one.
Mineralocorticoids - A class of hormones that maintain plasma volume and electrolyte balance (sodium and potassium), such as aldosterone.
57
What is defined as stress hormones released by the adrenal cortex, such as cortisol and cortisone?
Corticosteroids
58
What is cortisol's function?
Its function is to help to generate glucose, through the degradation of proteins (amino acids) during a process called gluconeogenesis in the liver, as an energy source for both the central nervous system (the brain) and skeletal muscles during physical exercise.
A metaphor to illustrate this process is the situation in which you resort to burning the furniture to keep warm once you exhaust your supply of firewood.
It is also involved in the process of lipolysis, or the mobilization and breakdown of fats (fatty acids) for energy.
Clinical studies have linked increased levels of cortisol with suppression of the immune system. It appears that cortisol metabolizes (degrades) white blood cells. As the number of white blood cells decreases, the efficiency of the immune system decreases, setting the stage for illness and disease.
It has also come to light that increased cortisol can direct excess amounts of cholesterol into the blood, thereby adding to associated artery plaque buildup and leading to hypertension and coronary heart disease.
59
What is defined as a stress hormone released by the adrenal glands that helps the body prepare for fight or flight by promoting the release of glucose and lipids in the blood for energy metabolism?
Cortisol
60
What secretes catecholamines (epinephrine and norepinephrine), which act in a similar fashion as those secreted at the endings of sympathetic nerves?
Adrenal medulla. The adrenal medulla releases 80 percent epinephrine and 20 percent norepinephrine. (remember 5:1 ratio)
61
What is the multiplicative factor of epinephrine found in the blood during stress compared to samples taken at rest?
Up to 300 times.
62
What may be the cause of Americans suffering from chronic fatigue syndrome?
Adrenal fatigue as a result of prolonged stress. Because of the amount of chronic stress many people admit to experiencing, the adrenal glands begin to work overtime. Signs of exhaustion and the inability to produce and release the host of catecholamines and hormones for fight or flight appear to give credence to Hans Selye’s general adaptation syndrome.
The symptoms of adrenal insufficiency include fatigue, dizziness, low blood sugar (resulting in cravings and subsequent weight gain), poor libido, and depression.
Weak adrenals are associated with the incidence of autoimmune diseases, ranging from chronic fatigue syndrome and lupus to rheumatoid arthritis. Because of the complexities of human physiology, poor adrenal function is also associated with aggravated symptoms of menopause.
Addison’s disease is the name given to those with adrenal failure, a condition where the adrenal glands are no longer able to produce and secrete the necessary hormones for metabolic function.
63
Not only does the posterior hypothalamus initiate activation of the sympathetic nervous system, but it also has a direct pathway to the adrenal medulla called?
Pregonglionic neuron.
64
What does the adrenal medulla secrete when stimulated by the hypothalamus?
Epinephrine and norepinephrine.
65
What is the goal of these catecholamines traveling in the bloodstream?
Reinforce the efforts of the sympathetic drive, which has already released these same substances through sympathetic neural endings throughout the body.
The release of epinephrine and norepinephrine from the adrenal medulla acts as a backup system for these biochemical agents to ensure the most efficient means of physical survival.
66
Why is the travel time different for the catecholamines released from the sympathetic nervous system (which was stimulated by the posterior hypothalamus) different than the catecholamines secreted by the adrenal medulla which was also stimulated by the posterior hypothalamus via the pregonglionic neuron?
Sympathetic nervous system releases via neural endings while the adrenal medulla releases into the bloodstream.
Because their release is via the bloodstream rather than neural endings, travel time is longer (approximately 20 to 30 seconds), and unlike the release of these substances from sympathetic neural endings, the effects of catecholamines from the adrenal medulla can last as long as 2 hours when high levels of secretions are circulating in the bloodstream.
Intermediate stress effects: The hormonal response triggered by the neural aspects of the adrenal medulla that are released directly into the blood, lasting minutes to hours.
67
When is the third and more potent system joining the efforts of the nervous and endocrine systems to prepare the body for real or perceived danger?
If the perceived threat continues beyond several minutes.
Neural impulses received by the hypothalamus as potential threats create a chain of biochemical messages, which like a line of falling dominos cascade through the endocrine-system glands. Because the half-life of these hormones and the speed of their metabolic reactions vary in length from hours to weeks in some cases, this chain of reactions is referred to as the prolonged effect of stress.
Prolonged effect of stress: Hormonal effects that may take days or perhaps more than a week to be fully realized from the initial stress response.
68
What are biochemical pathways referred as?
An axis.
69
What ACTH axis and HPA axis stand for? Which mean the same thing.
ACTH - Adrenocorticotropic hormone axis
HPA - Hypothalamic-pituitary-adrenal axis
70
What is the definition of ACTH axis along with its other term, HPA axis?
A physiological pathway whereby a message is sent from the anterior hypothalamus to the anterior pituitary gland, then on to the adrenal gland to release a flood of stress hormones for fight or flight.
The hypothalamic-pituitary-adrenal axis, a term synonymous with the ACTH axis.
71
What does the anterior hypothalamus begins to release and what does it stand for?
The ACTH axis from the anterior hypothalamus, begins to release CRF.
CRF stands for corticotropin-releasing factor.
72
What does the anterior hypothalamus begin to release via what and what does the acronym of the chemical stand for?
The ACTH axis from the anterior hypothalamus, begins to release CRF.
CRF stands for corticotropin-releasing factor.
73
What does corticotropin-releasing factor in turn activate?
It activates the anterior pituitary gland to release ACTH. Adrenocorticotropic hormones.
74
How does the ACTH travel and what does it in turn activate?
It travels along the bloodstream and activates the adrenal cortex.
75
What is defined as the portion of the adrenal gland that produces and secretes a host of corticosteroids (e.g., cortisol and aldosterone).
Adrenal cortex.
76
After ACTH travels through the blood and activates the adrenal cortex, what is next?
The adrenal cortex releases a set of corticosteroids (cortisol and aldosterone), which act to increase metabolism and alter body fluids, and thus blood pressure, respectively.
77
What are the effects of the release of corticosteroids and how long to do they activate their functions?
What is also important to note about increased secretions of cortisol?
The effects of hormones released by the adrenal cortex are considered to be prolonged because they activate their functions for minutes to hours. Note that increased secretions of cortisol in the blood act primarily to ensure adequate supplies of blood glucose for energy metabolism.
However, when increasingly high levels of cortisol are observed because of chronic stress, this hormone compromises the integrity of several physiological systems.
78
Recap the path of the hypothalamus to cortisol and aldosterone.
From the anterior hypothalamus via the adrenocorticotropic hormone (ACTH) axis, it begins to secrete corticotropin-releasing factor (CRF).
This corticotropin-releasing factor then stimulates the anterior pituitary gland that then releases adrenocorticotrophic (ACTH) hormones.
These adrenocorticotrophic hormones are then used to stimulate the adrenal cortex which then produce corticosteroids.
The two corticosteroids that are released are dependent on the situation (perceived threats). Those two corticosteroids are glucocorticoids and mineralocorticoids.
Glucocorticoids consist of cortisol while the mineralocorticoids consist of aldosterone.
79
What are the impacts of glucocorticoids and mineralocorticoids on the body?
Cortisol Impacts:
```
Mobilizes free fatty acids
Mobilizes proteins
Metabolizes amino acids
Demineralizes amino acids
Initiates gluconeogenesis
Increases serum glucose levels
Decreases body weight
Promotes muscle wasting
Breaks down antibodies
Impairs immune function
Depletes vitamins
Causes beta cell depletion
Decreases insulin production
Increases arterial blood pressure
```
```
Aldosterone Impacts:
Promates Na+ retention
Enhances K+ elimination
Osmotic retention of H20
Increases blood pressure by increasing blood volume
```
80
How does cortisol mobilize free fatty acids?
In times of stress when the body requires energy, fatty acids are released from adipose cells (fat cells) and mobilized for use. The process begins when levels of glucagon and adrenaline in the blood increase and these hormones bind to specific receptors on the surface of adipose cells.
81
How does cortisol mobilize proteins?
Cortisol accelerates the breakdown of proteins into amino acids (except in liver cells).
82
How does cortisol metabolize amino acids?
These amino acids move out of the tissues into the blood and to liver cells, where they are changed to glucose in a process called gluconeogenesis.
83
What is caused by chronic mental antsyness (frustration)?
Multitasking generation with the age of high technology. Addiction to smartphones, text messages, email, podcasts and the web.
A hyperkinetic mind doesn't know how to turn off. Habitual multitasking may condition the brain to an overexcited state, making it difficult for people to focus even when they want or need to.
Quantity is not quality.
84
With MRI technology, what are has researchers identified when it comes to "multitasking"?
With the use of MRI technology, researchers, including Jordan Grafman, have identified one specific area of the brain’s cortex, Brodmann’s area 10, as the site specific for alternating attention from one task to another. The prefrontal cortex, which houses Brodmann’s area 10, is one of the last regions of the brain to mature and the first to decline as a result of the aging process. As such, youngsters up to age 22 and those over the age of 60 do not multitask well.
Research studies reveal that when young adults perform two or more tasks simultaneously, the amount of errors increases dramatically. Although there may be many causes for poor attention span (from the TV remote control to the abundance of toxic food chemicals), the combination of short attention span and the increased use of electronic devices becomes dangerous. The take-home message is that multitasking decreases efficiency.
85
What is important to know about how multitasking has on processing information on a deeper context?
Although students may excel at locating and manipulating information via the Internet, their reach may be broad but ultimately quite shallow. Moreover, their ability to process the information in a deeper context is considered poor by most educational standards, states Claudia Koonzt of Duke University. “It’s like they have too many windows open on their hard drive. In order to have a taste for sifting through different layers of truth, you have to stay with the topic and pursue it deeply rather than go across the surface with your toolbar”
86
What are the social implications of being wired for stress?
Virtual conversations will never replace the nuances of face-to-face expressions and body language that humans have developed over thousands of years of cohabitation and community building. Experts have also noticed a decrease in interaction among family members with a rise in household electronic gadgets, further eroding the family structure. Furthermore, addiction to cell phone use is fast becoming a reason for marriage counseling and breakups (University of Florida, 2007). Studies on the topic of Alzheimer’s support the theory that the brain needs stimulation to promote mental acuity. Stress research, however, validates the need for quiet time for the brain. When the brain is constantly stimulated (and overstimulated) these neurological impulses rewire the brain for perpetual stress.
87
What is defined as chain of physiological events stemming from the release of vasopressin or antidiuretic hormone (ADH)?
Vasopressin axis.
88
Where is vasopressin synthesized and what is released by?
Vasopressin is synthesized by the hypothalamus but it is released by the pituitary gland through a special portal system.
89
What is the primary purpose of vasopressin?
The primary purpose of vasopressin is to regulate fluid loss through the urinary tract. It does this in a number of ways, including water reabsorption and decreased perspiration.
90
By altering the blood volume, what is the pronounced affect of vasopressin?
It has as a pronounced effect on stroke volume, or the amount of blood that is pumped through the left ventricle of the heart with each contraction.
Consequently, ADH has a pronounced effect on blood pressure. Under normal circumstances, ADH regulates blood pressure by either increasing blood volume (changing the concentration of water in the blood) should it be too low, or decreasing blood volume when it becomes too high.
91
Under the influence of chronic stress, however, many regulatory mechanisms in the body lose their ability to maintain physiological homeostasis. What will increased secretions of vasopressin under duress contribute to?
Consequently, the increased secretions of vasopressin produced under duress will increase blood pressure even when someone already has elevated resting values; this is known as hypertension.
92
What does the purpose of vasopressin as well as aldosterone, epinephrine, and norepinephrine is to increase blood pressure to ensure that active muscles receive oxygenated blood, but under chronic stress in a resting state this hormonal response—the abundance of stress hormones—is literally overkill leading to?
Leading to hypertension and ultimately death caused by Coronary Heart Disease (CHD).
93
When the hypothalamus is stimulated, what else is released?
The release of thyrotropic hormone-releasing factor (TRF)
94
How is the transported and where does it go?
Transported through a special portal system to the anterior portion of the pituitary.
95
What does the anterior pituitary gland secrete when it is stimulated by TRF?
Thyrotropic hormone (TTH)
96
How does TTH travel and where does it go?
Once in the bloodstream, TTH follows a path to the thyroid gland.
97
What are the effects of TTH on the thyroid gland?
Stimulates the release of two more hormones: thyroxine and triiodothyronine.
98
What is the purpose of thyroxine and triiodothyronine?
The purpose of these two hormones is to increase overall metabolism, or basal metabolic rate (BMR).
Thyroxine is powerful enough to double one’s rate of metabolism. Note that the effects of this pathway are very prolonged. Because the production of thyroxine takes several days, it may be 10 days to 2 weeks before visible signs manifest as significant symptoms through this pathway.
99
What does thyroxine explain?
This explains why you may come down with a cold or flu a week after a very stressful encounter rather than the day after. The metabolic effects of thyroxine released through this pathway are increased workload on the heart muscle, increased gastrointestinal activity (e.g., gastritis), and, in some cases, a condition called cerebration or cerebral excitivity, which is associated with anxiety attacks and/or insomnia.
100
What is defined as a term used to describe the neurological excitability of the brain, associated with anxiety attacks and insomnia?
Cerebration.
101
What is defined as a term used to describe the neurological excitability of the brain, associated with anxiety attacks and insomnia?
Cerebration.
102
What is a great metaphor for the 3 levels of effects that happen in your body?
Similarly, our bodies are composed of several communication systems, each with its own time element and function, the overall purpose being to prepare the body for physical survival. As illustrated by this story, there are many backup systems, fast and slow, to get the message through.
You have very important information to give another person.
First you text them because it is instantaneous and it is the quickest way to get your message to them. (this is like the action of the sympathetic nervous system)
As a backup, you also send an email in case no one responds. This is quick but still takes a few minutes. (this action can be equivalent to the preganglionic nerve to the adrenal medulla)
Next, you send a hard copy of the information through the mail. This is a more comprehensive means of information to be sent, but takes much longer. (this is like the neuroendocrine or biochemical pathways or axises)
103
What threats does the body prepare for physically?
They can be physical, mental, emotional, or spiritual in nature.
Repeated physical arousal suggests that the activation of the stress response is an obsolete mechanism for dealing with stressors that do not pertain to physical survival.
104
What can the inability of the body to return to homeostasis have effects on?
Cardiovascular system, digestive system, musculoskeletal system, and, research now indicates, the immune system.
105
What happens when organs are locked in a pattern of overactive metabolic activity?
They will eventually show signs of dysfunction.
106
What can constant pressure and repeated wear and tear on the arteries and blood vessels cause? What about the digestive system?
It can cause tissue damage to the inner lining of these organs.
Effects such as constipation, gastritis, diarrhea, and hemorrhoids can happen in the digestive system.
107
What does the medical profession choose prior to the start of each decade?
One area of human physiology to study in-depth.
The brain was chosen in 1990.
2000, the medical profession chose the bone and joint.
108
What is another name for magnetic resonance imaging (MRI)?
Neuroimaging. Thousands of studies have been conducted to determine which aspects of the brain are active in a variety of mental states and thought processes
109
What has helped further to understand brain structure and specific physiology and the brain's function?
Electroencephalagraph (EEG)
110
What together form conscious memories of emotional events?
Hippocampus and the amydala.
111
What is highly sensitive to the stress hormone cortisol which aids in memory formation of stress?
Hippocampus.
112
What region is rich in receptor sites for glucocorticoids?
The Hippocampus.
113
What is responsible for the emotional content of memory especially fear?
The amygdala.
114
Repeated exposure of what accelerates the aging process of the hippocampus and may, in fact, damage and shrink brain cells?
Cortisol.
Moreover, chronic stress may affect memory and learning processes. (In Vietnam vets with post-traumatic stress disorder [PTSD], this region of the brain was 26 percent smaller than in their peers without PTSD.)
115
What was revealed by Sapolsky about damage to brain cells in animals caused by chronic stress?
Damage to the brain was irreversible.
116
What was concluded by McEwen about the human brain?
It is wired for stress, or "allostatic load" as he calls it.
117
Define allostatic load.
A term coined by stress researcher Bruce McEwen to replace the expression “stressed out”; the damage to the body when the allostatic (stress) response functions improperly or for prolonged states, causing physical damage to the body.
118
What term by neuroscientists did they use when they realized that the brain is capable of generating new connections to various brain cells, recruit various brain tissue for a host of functions, and generate new cell growth?
Neuroplasticity. Coined in 1948 but not used widely until 1960s.
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Summary
Psychophysiology is a term to describe the body’s physiological reaction to perceived stressors, suggesting that the stress response is a mind-body phenomenon.
There are three physiological systems that are directly involved in the stress response: the nervous system, the endocrine system, and the immune system.
The nervous system comprises two parts: the central nervous system (CNS) and the peripheral nervous system (PNS). The CNS includes three levels: the vegetative, the limbic, and the neocortical.
The limbic system houses the hypothalamus, which controls many functions, including appetite and emotions. The neocortical level processes and decodes all stimuli.
The most important part of the PNS regarding the stress response is the autonomic nervous system, which activates sympathetic and parasympathetic neural drives. Sympathetic drive causes physical arousal (e.g., increased heart rate) through the secretion of epinephrine and norepinephrine, whereas parasympathetic drive maintains homeostasis through the release of ACh. The two neural drives are mutually exclusive, meaning that you cannot be aroused and relaxed at the same time.
The endocrine system consists of a series of glands that secrete hormones that travel through the circulatory system and act on target organs. The major stress gland is the adrenal gland.
The adrenal gland has two parts, each performing different functions. The cortex (outside) secretes cortisol and aldosterone, while the medulla (inside) secretes epinephrine and norepinephrine.
The nervous system and endocrine system join together to form metabolic pathways or axes. There are three pathways: the ACTH axis, the vasopressin axis, and the thyroxine axis.
The body has several backup mechanisms to ensure physical survival. These systems are classified as immediate, lasting seconds (sympathetic drive); intermediate, lasting minutes (adrenal medulla); and prolonged, lasting hours if not weeks (neuroendocrine pathways). Each system is involved in several metabolic pathways.
Stress is considered one of the primary factors associated with insomnia. Good sleep hygiene consists of behaviors that help promote a good night’s sleep rather than detract from it, including decreased caffeine consumption, consistent bedtimes, and a host of effective relaxation techniques that enhance sleep quality.
A decade of brain research reveals that humans are hard-wired for stress through an intricate pattern of neural pathways designed for the fight-or-flight response. Research also suggests that chronic stress appears to atrophy brain tissue, specifically the hippocampus.
