Pituitary dwarfism is caused by problems arising from the pituitary gland. The pituitary gland, also called the hypophysis, is a gland at the base of the brain that produces many different hormones. This gland is divided into the anterior (front) and posterior (back) halves. The anterior pituitary produces six hormones: growth hormone, adrenocorticotropin (corticotropin), thyroid stimulating hormone (thyrotropin), prolactin, follicle stimulating hormone, and lutenizing hormone. The posterior pituitary gland only produces two hormones: antidiuretic hormone (vasopressin) and oxytocin.
The growth process begins in the lower part of the forebrain in a small organ called the hypothalamus. The hypothalamus releases hormones that regulate the production of other hormones. When the hypothalamus releases growth hormone-releasing hormone (GHRH), the anterior pituitary is stimulated to release growth hormone (GH). Growth hormone then acts on the liver and other tissues and stimulates them to secrete insulin-like growth factor-1 (IGF-1). IGF-1 directly promotes the development of bone and muscle, causing bones to grow in length, and muscles to increase protein synthesis (make more protein).
Since growth is a complex phenomenon, it may be slowed down or stopped by abnormalities arising at any point in the process. Thus, dwarfism can result if there is a deficiency in any of these hormones, if there is a failure in the receptor cells receiving the hormonal stimuli, or if the target cells are unable to respond.
At its most basic, pituitary dwarfism results from decreased production of hormones by the anterior pituitary. When none of the hormones of the anterior pituitary are adequately produced, this is called panhypopituitarism. A common form of pituitary dwarfism is due to deficiencies in the production of growth hormone (GH). When less GH than normal is produced during childhood, an individual's arms, legs, and other structures continue to develop in normal proportions, but at a decreased rate.
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I swear it's the cell membrane.. I'm not sure though
Answer:
The surface area of the cell increases to volume ratio
Explanation:
As a cell grows, the surface area of the cell increases to volume ratio. When cell division occurs, the surface area is distributed and each daughter cell have less surface area but with the passage of time, the surface area increases. The main function of mitosis is to increase the population of the cell, the cell must be divided into two daughter cells in the process of mitosis. Tumors occurs when the process of mitosis is uncontrollable. One observation that is found interesting while looking at the onion root tip cells is the multiplication of the cells by the process of mitosis.
Answer:
vasoconstriction of capillaries.
baroreceptors in the aortic arch.
Explanation:
Vasoconstriction of capillaries and baroreceptors in the aortic arch are the two quick responses of body to maintain normal blood pressure during hemorrhage. Vasoconstriction is very necessary for lowering acute blood loss during hemorrhage means escape of blood from a ruptured blood vessel as well as maintain body heat and arterial pressure. The function of baroreceptors is to respond to the change in the tension of the arterial wall when blood pressure changes.
D) Blue Jays and Finches nest in the same Oak Trees.
Explanation:
This is an example of competition because two species are for the same thing, in this case, oak trees to nest in.
