Unit 3 Communication Control And Integration Chapter 25 Endo

Unit 3 Communication Control And Integrationchapter 25 Endocrine Re

Compose 400 words or more discussion to respond the following: What is meant by the term target cells ? How are steroid hormones able to pass through the cell’s plasma membrane easily? Name some of the different general types of Non steroid hormones. Give an example of each. Name some ways in which hormones can work together to regulate a tissue. Why are Prostaglandins (PGs ) sometimes called tissue hormones? Why are PGs considered to be an important in Clinical application? What are the two main divisions of the Pituitary Gland called? Name three hormones produced by adenohypophysis, and give their main functions. What is a tropic Hormone? A releasing hormone? Name the two hormones of the neurohypophysis. Where is the thyroid located? How calcitonin and parathyroid hormone act together to regulate the homeostasis of blood calcium concentration? Name some effects of Cortisol in the body. Name two of the four principal hormones secreted by the pancreatic islets. In what way do insulin and glucagon exert antagonistic influences on the concentration of Glucose in the blood? What are the major hormones secreted by reproductive tissues (Gonads and placenta)?

Paper For Above instruction

The endocrine system plays a pivotal role in regulating physiological processes through the secretion of hormones that act on specific target cells. The term "target cells" refers to cells that possess specific receptors enabling them to respond to particular hormones. These cells are vital because they determine the hormone's effects, enabling precise regulation of bodily functions such as growth, metabolism, and reproduction. The ability of steroid hormones to pass through the plasma membrane easily is due to their lipophilic (fat-soluble) nature. Steroid hormones, derived from cholesterol, are nonpolar molecules that diffuse freely through the lipid bilayer of cell membranes, allowing them to directly interact with intracellular receptors inside the cell nucleus or cytoplasm to modulate gene expression.

Non-steroid hormones, also known as peptide or protein hormones, differ significantly in structure and mode of action. Common types include peptide hormones such as insulin and growth hormone, which are composed of amino acids and act via second messenger systems like cyclic AMP (cAMP). Examples include insulin, pivotal in glucose regulation, and oxytocin, which influences childbirth and lactation. Another class comprises amino acid derivatives, such as thyroid hormones, which are lipid-soluble but function differently from steroid hormones, and catecholamines like adrenaline, which prepare the body for fight-or-flight responses. Hormones can work synergistically, antagonistically, or permissively to regulate tissues. For instance, insulin promotes glucose uptake, while glucagon stimulates glucose release, exemplifying antagonistic interaction essential for blood glucose homeostasis.

Prostaglandins (PGs) are sometimes called tissue hormones because they are produced locally within tissues and act locally to influence processes like inflammation, blood flow, and uterine contractions. Their local action makes them crucial in clinical applications such as managing childbirth, controlling inflammation, and treating cardiovascular conditions. The pituitary gland is divided into two main parts: the anterior pituitary (adenohypophysis) and the posterior pituitary (neurohypophysis). The adenohypophysis secretes hormones like growth hormone (stimulates body growth), thyroid-stimulating hormone (TSH; stimulates thyroid gland), and adrenocorticotropic hormone (ACTH; stimulates cortisol release from adrenal cortex). These hormones often regulate or stimulate other endocrine glands, thus classified as tropic hormones. Releasing hormones, secreted by the hypothalamus, include thyrotropin-releasing hormone (TRH) and gonadotropin-releasing hormone (GnRH). The neurohypophysis stores and releases hormones produced by the hypothalamus, specifically oxytocin and vasopressin (antidiuretic hormone).

The thyroid gland, located anteriorly in the neck, regulates metabolism through hormones like thyroxine (T4) and triiodothyronine (T3). Calcitonin and parathyroid hormone (PTH) work antagonistically: calcitonin lowers blood calcium levels by inhibiting osteoclast activity, while PTH raises blood calcium by stimulating osteoclasts and increasing intestinal absorption of calcium via activation of vitamin D. Cortisol, secreted by the adrenal cortex, has multiple effects including increasing blood glucose, suppressing inflammation, and modulating immune responses. The pancreas secretes principal hormones like insulin and glucagon from the pancreatic islets. Insulin lowers blood glucose by promoting cellular uptake, whereas glucagon raises blood glucose levels by stimulating hepatic glycogenolysis, thus exerting antagonistic effects essential for maintaining glucose homeostasis.

Reproductive tissues secrete major hormones such as testosterone, estrogen, progesterone, and human chorionic gonadotropin (hCG) from the placenta. These hormones regulate reproductive processes, secondary sexual characteristics, pregnancy maintenance, and fetal development. Overall, the endocrinological control mechanisms involving these hormones maintain homeostasis and ensure proper physiological functioning throughout the body.

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