Peer Assessment 2
Choose one out of paracrine signalling, endocrine signalling, autocrine signalling and direct signalling and describe brie y the process by which this occurs.
The Endocrine signalling occurs over long distances in the body and the signal is sent through the blood. Firstly, the cell inside the pituitary gland sends hormones into the blood stream over a long distance and once it gets reaches to a cell with the right receptor, the hormones will attach themselves to the receptor of that cell and go inside the cell and trigger a response. For example, the anterior pituitary lobe will release adrenocorticotropic hormone (ACTH) to stimulate cortisol production in the adrenal glands when you’re stressed. (Sargis, 2018).
Pick a …show more content…
The hormone insulin, is a main regulator of the glucose (sugar) levels in the blood. Insulin is released by pancreatic beta cells in the islets of Langerhan in response to elevated levels of nutrients in the blood. Insulin triggers the uptake of glucose, fatty acids and amino acids into liver, adipose tissue and muscle and promotes the storage of these nutrients in the form of glycogen, lipids and protein respectively. Failure to uptake and store nutrients results in diabetes. (Hooper, 2018)
Type-1 diabetes is characterized by the inability to synthesize insulin, whereas in type-2 diabetes the body becomes resistant to the effects of insulin, presumably because of defects in the insulin signalling pathway. (Hooper, 2018).
When food such as carbohydrates is eaten, it is broken down into sugar inside the body and raises the glucose or sugar level inside the blood. The pancreas senses the rise in sugar level in the body and so it releases the hormone insulin into the blood stream to encourage the uptake of the excess sugar/glucose. The message or signal from the hormone is composed of trigger mechanisms that serves as signals throughout the cell and activates the insulin receptor …show more content…
There is also a counter mechanism in the body that stop the secretion of insulin beyond a certain limit. (Wikipedia, 2018).
Action on the cell
After insulin enters the bloodstream, it binds to a membrane-spanning glycoprotein receptor.
This glycoprotein is embedded in the cellular membrane and has an extracellular receptor domain, made up of two α-subunits, and an intracellular catalytic domain, made up of two β- subunits. The α-subunits act as insulin receptors and the insulin molecule acts as a ligand.
Together, they form a receptor-ligand complex. (Wikipedia, 2018)
Binding of insulin to the α-subunit results in a conformational change in the membrane-bound glycoprotein, which activates tyrosine kinase domains on each β-subunit. The tyrosine kinase activity causes an auto phosphorylation of several tyrosine residues in the β-subunit. The phosphorylation of 3 residues of tyrosine is necessary for the amplification of the kinase activity. Once the tyrosine kinase is activated in the insulin receptor, it triggers the activation of the docking proteins, also called IRS (1-4) that are important in the signalling pathway, and
Choose one out of paracrine signalling, endocrine signalling, autocrine signalling and direct signalling and describe brie y the process by which this occurs.
The Endocrine signalling occurs over long distances in the body and the signal is sent through the blood. Firstly, the cell inside the pituitary gland sends hormones into the blood stream over a long distance and once it gets reaches to a cell with the right receptor, the hormones will attach themselves to the receptor of that cell and go inside the cell and trigger a response. For example, the anterior pituitary lobe will release adrenocorticotropic hormone (ACTH) to stimulate cortisol production in the adrenal glands when you’re stressed. (Sargis, 2018).
Pick a …show more content…
The hormone insulin, is a main regulator of the glucose (sugar) levels in the blood. Insulin is released by pancreatic beta cells in the islets of Langerhan in response to elevated levels of nutrients in the blood. Insulin triggers the uptake of glucose, fatty acids and amino acids into liver, adipose tissue and muscle and promotes the storage of these nutrients in the form of glycogen, lipids and protein respectively. Failure to uptake and store nutrients results in diabetes. (Hooper, 2018)
Type-1 diabetes is characterized by the inability to synthesize insulin, whereas in type-2 diabetes the body becomes resistant to the effects of insulin, presumably because of defects in the insulin signalling pathway. (Hooper, 2018).
When food such as carbohydrates is eaten, it is broken down into sugar inside the body and raises the glucose or sugar level inside the blood. The pancreas senses the rise in sugar level in the body and so it releases the hormone insulin into the blood stream to encourage the uptake of the excess sugar/glucose. The message or signal from the hormone is composed of trigger mechanisms that serves as signals throughout the cell and activates the insulin receptor …show more content…
There is also a counter mechanism in the body that stop the secretion of insulin beyond a certain limit. (Wikipedia, 2018).
Action on the cell
After insulin enters the bloodstream, it binds to a membrane-spanning glycoprotein receptor.
This glycoprotein is embedded in the cellular membrane and has an extracellular receptor domain, made up of two α-subunits, and an intracellular catalytic domain, made up of two β- subunits. The α-subunits act as insulin receptors and the insulin molecule acts as a ligand.
Together, they form a receptor-ligand complex. (Wikipedia, 2018)
Binding of insulin to the α-subunit results in a conformational change in the membrane-bound glycoprotein, which activates tyrosine kinase domains on each β-subunit. The tyrosine kinase activity causes an auto phosphorylation of several tyrosine residues in the β-subunit. The phosphorylation of 3 residues of tyrosine is necessary for the amplification of the kinase activity. Once the tyrosine kinase is activated in the insulin receptor, it triggers the activation of the docking proteins, also called IRS (1-4) that are important in the signalling pathway, and