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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Habitat loss is contributing to the permanent loss of species, the weakening of ecosystems, and is impacting the overall health of the planet.
Example:
While tree-clearing is a significant cause of habitat loss in Australia, other major contributing factors include altered bushfire frequency and the introduction of pest species that make habitats unsafe for native species or outcompete them. Meanwhile, on the Great Barrier Reef, the impacts of human-induced climate change are altering the habitats of corals, leading to large-scale coral bleaching. Over time, destruction of such habitats leads to reduced biodiversity and weakening of the Earth’s ecosystem.
Answer:
A.
Explanation:
A parasite does not feed it's host; in fact, it takes food energy/ food from it's host.
Answer:
True
Explanation:
Let the allele for green color of pods be G
and the allele for yellow color of pods be g
Phenotype of true breeding parent with green colored seeds is GG
Phenotype of true breeding parent with yellow colored seeds is gg
In F1 cross
GG mates with gg
Genotype of offspring - Gg
Phenotype of offspring - Green seed
Since the offspring has both the allele for green and yellow seeds color but yet only green is expressed. This indicate that green allele dominated the expression of yellow allele thus, it can be concluded that green seed pods were dominant over yellow seed pods.
