Adrenaline (advanced)
Human homeostasis or the dynamic stability of the internal conditions of the body can be threatened by a number of factors in such a situation a stress reaction is produced in response to the stimulation of the nervous system and the hormonal system this reaction helps us to avoid danger and maintain homeostasis in a stressful situation the sympathetic nervous
System is activated stimulating the release of a hormone called adrenaline or epinephrine by the adrenal medulla the combined effect of adrenaline and the sympathetic nervous system leads to a fight or flight reaction the main symptoms include dilation of the pupils an increase in the heart rate and in the circulatory minute volume a release of glucose into the
Bloodstream from the liver and skeletal muscles causing an increase in blood glucose level dilation of the blood vessels in the brain skeletal muscles and heart and constriction of the blood vessels in the intestines kidneys and skin the smooth muscle in the blood vessels found in different organs contains either alpha or beta adrenaline receptors when binding
To alpha receptors adrenaline causes blood vessels to contract while binding to beta receptors it dilates blood vessels the smooth muscle in our intestines kidneys and skin typically contains alpha receptors when the adrenaline is bound the alpha receptor activates the g protein which has three subunits its alpha subunit converts gdp into gtp and then activates
The phospholipase c enzyme phospholipase c breaks the pip2 that is the phospho-inositol diphosphate molecule into ip3 and dag that is inositol triphosphate and diacylglycerol ip3 causes the endoplasmic reticulum to release calcium ions while dag activates the protein kinase c enzyme calcium ions and protein kinase c have the joint effect of contracting smooth
Muscle cells constricting blood vessels and decreasing the blood supply to the organs the smooth muscle in our heart brain and blood vessels typically contains beta receptors thus the blood supply to these organs is increased during an alarm reaction adrenaline binds to the beta receptors in the smooth muscle of blood vessels this activates the g protein
The alpha subunit replaces the gdp with a gtp and activates an enzyme called adenolate cyclase this enzyme converts atp into cyclic amp also known as camp this results in the dilation of blood vessels and thereby the increase of the blood supply to the organ as adrenaline causes the contraction of certain blood vessels and the dilation of others it basically
Sends blood to the skeletal muscles the heart and the brain as an effective adrenaline the blood glucose level rises thus providing energy for the muscles the heart and the brain glucose is stored in a polymer form as glycogen primarily in the liver and the skeletal muscles this is the quickest source of glucose in the body the beta receptors in liver cells
Bind adrenaline then the alpha subunit of the g protein activates the adenolate cyclase which synthesizes cyclic amp camp activates the protein kinase a enzyme this phosphorylates and thereby activates the glycogen phosphorylase enzyme which catalyzes the release of glucose phosphates from glycogen the phosphate groups in the glucose phosphate molecules are
Removed by an enzyme and glucose is released into the blood the heart muscle contains a large amount of a subtype of the beta receptor the beta-1 receptor since adrenaline stimulates the heart through this receptor drugs known as beta blockers can be used to reduce the load on the heart there are selective beta01 blockers but there are those that act on all
Types of beta receptors the use of beta blockers may be necessary for disorders of the heart rate or high blood pressure or after a heart attack in order to relax the heart muscle so so i
Transcribed from video
Adrenaline (advanced) aline, also known as epinephrine By تكامل البطاقة الذكية في سوريا