Question

Can you summarize this video in your own words? What is the main idea? What is something you find interesting? At least 12 sentences https://www.youtube.com/watch?v=ER49EweKwW8&feature=youtu.be

Answer 1

Human body is a complex system composed of trillions of cell. These cells group together to form tissues, organ and organ system. These cells mostly interact with one another via the nervous system in which the neurons play a major role. However, for organs situated at larger distances from one another say for example, the brain and the kidney or the gonads, interaction via the neurons is not possible. Here comes into play the endocrine system. It is system of chemical messengers/signals (known as hormones) which are secreted through small glands located in various part of the body. These hormones are released into the bloodstream which carries them to target organs usually far off from their point of secretion (unlike autocrine and paracrine system). They also help maintain the homeostasis in the body.

The major and most important endocrine gland is the hypothalamus, situated in the forebrain. It is usually called the control region because of its dual role in the nervous system as well as the endocrine system. It majorly acts as a link between the two and stimulates secretion of hormones from the pituitary gland, which is also situated in the brain. The pituitary makes two major hormones called ADH and oxytocin. ADH has antidiuretic effect and helps to maintain fluid volume of the body while oxytocin helps in uterine contraction during pregnancy. Below the hypothalamus lies the pituitary gland, a pea sized gland also called the master gland as it takes the signal from the hypothalamus and sends them to all the other endocrine gland. Among the glands under the control of pituitary, the thyroid is one located in the neck near the trachea. Its main job is to stimulate and regulate metabolism through the hormone T3 and T4 (thyroxin) that it secretes. Behind it we find the parathyroid, four spots on the back side of thyroid, helping to maintain the calcium levels in the body through PTH hormone secreted by it. Next we find another important gland called the adrenal gland located on top of the kidney. It has two part: an outer cortex and an inner medulla. The cortex produces steroid hormones called cortisol (stress hormone which produce blood sugar in time of stress to provide energy) and aldosterone (which regulate blood volume). Medulla, on the other hand, produces catecholamine (epinephrine and norepinephrine). These generate the fight-or-flight response (also called the acute stress response) during stress. Next comes the gonads which includes the ovaries in females and testis in males. They produce the sex hormones. Testosterone in males and estrogen and progesterone in females. Their main role is to generate secondary sexual characteristics.

Another important gland is pancreases located in the upper part of the abdomen. It is not directly controlled by the pituitary gland. It major function is to control the blood sugar through production of insulin and glucagon. Without these hormone we cannot regulate the sugar balance thus leading to major diseases like diabetes.

A very important and unique aspect of the endocrine signal is the way they regulate the entire secretion and target response system. In a body at any particular time many different hormones are produces and released into the blood stream. There is always a chance that a particular hormone rather than going to its target organ reaches some other organ and produces an undesirable effect in it. However, such thing do not happen generally. This is mostly because the endocrine system is a highly regulated system which runs in receptor specific manner. Receptor-ligand interaction ensures that no undesirable effect is produced in any other part of the body.