Fight or flight and homeostasis

Biology Paper 2, Topic 6 "Inheritance, variation and selection" Know that some disorders are inherited. These disorders are caused by the inheritance of certain alleles. Polydactyly having extra fingers or toes is caused by a dominant allele. Cystic fibrosis a disorder of cell membranes is caused by a recessive allele.

Fight or flight and homeostasis

Little epinephrine is found in other tissues, mostly in scattered chromaffin cells. Following adrenalectomyepinephrine disappears below the detection limit in the blood stream. Sympathetic nerve receptors are classified as adrenergic, based on their responsiveness to adrenaline.

In adrenalectomized patients hemodynamic and metabolic responses to stimuli such as hypoglycemia and exercise remain normal. This was first demonstrated using the denervated pupil of a Fight or flight and homeostasis as an assay, [26] later confirmed using a biological assay on urine samples.

The development of extraction methods and enzyme-isotope derivate radio-enzymatic assays REA transformed the analysis down to a sensitivity of 1 pg for epinephrine. Exercise induces progressive airway dilation in normal subjects that correlates with work load and is not prevented by beta blockade.

Beta blockade with propranolol causes a rebound in airway resistance after exercise in normal subjects over the same time course as the bronchoconstriction seen with exercise induced asthma. The hormonal component includes the release of epinephrine, an adrenomedullary response that occurs in response to stress and that is controlled by the sympathetic nervous system.

The major emotion studied in relation to epinephrine is fear. In an experiment, subjects who were injected with epinephrine expressed more negative and fewer positive facial expressions to fear films compared to a control group. These subjects also reported a more intense fear from the films and greater mean intensity of negative memories than control subjects.

Overall, the greater amount of epinephrine is positively correlated with an arousal state of negative feelings. These findings can be an effect in part that epinephrine elicits physiological sympathetic responses including an increased heart rate and knee shaking, which can be attributed to the feeling of fear regardless of the actual level of fear elicited from the video.

Although studies have found a definite relation between epinephrine and fear, other emotions have not had such results. In the same study, subjects did not express a greater amusement to an amusement film nor greater anger to an anger film.

Findings support the idea that epinephrine does have a role in facilitating the encoding of emotionally arousing events, contributing to higher levels of arousal due to fear.

The release of epinephrine due to emotionally stressful events, which is endogenous epinephrine, can modulate memory consolidation of the events, ensuring memory strength that is proportional to memory importance. Post-learning epinephrine activity also interacts with the degree of arousal associated with the initial coding.

Epinephrine may also play a role in elevating arousal and fear memory under particular pathological conditions including post-traumatic stress disorder. For noradrenaline to be acted upon by PNMT in the cytosol, it must first be shipped out of granules of the chromaffin cells.

VMAT1 is also responsible for transporting newly synthesized adrenaline from the cytosol back into chromaffin granules in preparation for release.

Cyclic AMP binds to the regulatory subunit of protein kinase A: Protein kinase A phosphorylates phosphorylase kinase. Calcium ions bind to calmodulin proteins, a protein present in all eukaryotic cells, which then binds to phosphorylase kinase and finishes its activation.

Phosphorylase kinase phosphorylates glycogen phosphorylasewhich then phosphorylates glycogen and converts it to glucosephosphate.

A general increase in sympathetic neural activity is usually accompanied by increased adrenaline secretion, but there is selectivity during hypoxia and hypoglycaemia, when the ratio of adrenaline to noradrenaline is considerably increased. Myocardial infarction is associated with high levels of circulating epinephrine and norepinephrine, particularly in cardiogenic shock.

Patients with BFT were found to have increased plasma epinephrine, but not norepinephrine. Failure of the adrenal cortex, as with Addisons disease, can suppress epinephrine secretion as the activity of the synthesing enzyme, phenylethanolamine-N-methyltransferasedepends on the high concentration of cortisol that drains from the cortex to the medulla.

However, the pharmacologist John Abel had already prepared an extract from adrenal glands as early asand coined the name epinephrine to describe it from the Greek for "on top of the kidneys" [58].

In the belief that Abel's extract was the same as Takamine's a belief since disputedepinephrine became[ when? Nevertheless, even among the latter, receptors for this substance are called adrenergic receptors or adrenoceptors, and pharmaceuticals that mimic its effects are often called adrenergics.The adrenal glands are located on the upper pole of each kidney.

Cardiovascular System - Human Veins, Arteries, Heart

In fact, their name designates their location: the prefix ad means "adjacent," and renal refers to the kidney. In the human body, they are small yellowish glands that weigh about five grams ( ounces) each.

Epinephrine, also known as adrenaline, is a hormone secreted by the medulla (inner part) of the adrenal glands, located on the kidneys. The adrenal glands are one of the body's endocrine glands (glands producing substances that are distributed by way of the bloodstream).

It can be diverted or utilize for fight or flight. If we didn’t have that sympathetic system, we would be blobs. That now led to the traditional understanding of the autonomic nervous system as a vagal system that could conserve or shut you down.

Temperature is an indicator of the amount of heat contained in a system and in the human body our temperature is an extension of basic body metabolism and a host of other factors.

Heat is a form of energy and every reaction in a human body occurs at a certain energy or temperature level thus.

The cardiovascular system consists of the heart, blood vessels, and the approximately 5 liters of blood that the blood vessels transport.

Fight or flight and homeostasis

Responsible for transporting oxygen, nutrients, hormones, and cellular waste products throughout the body, the cardiovascular system is powered by the body’s hardest-working organ — the heart, which is only about the size of a closed fist.

Those large white blobs (termed “lipid droplets”) in the white fat cells are what house our triglycerides (TAGs get used to this acronym, I’m going to use it a lot).The lipid droplets are what grow and shrink as TAGs come and go.

Tissues, organs, & organ systems (article) | Khan Academy