Ch 45 - Ch 45 (entire chapter: hormones for which specific...

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Ch 45 (entire chapter: hormones for which specific functions and glands which secret them are those mentioned in class) Hormone is a molecule that is secreted into the extracellular fluid, circulates in the blood or hemolymph and communicates regulatory messages throughout the body Endocrine system: 1 of the two basic systems for communication and rgulation throughout the body; these hormones regulate production, development, energy, metabolism, growth and behavior Nervous system: a network of specialized cells (neurons) that transmit signals along dedicated pathways whcih regulate neurons, muscle cells and endocrine cells target cells are cells that have receptors for a particular secreted molecule. Hormones secreted into extracellular fluids by endocrine cells reach target cells via bloodstream and triggers a response. Kidney and stomach contain endocrine cells and others are grouped in ductless organs called endocrine glands (secrete into); exocrine glands (carry secreted substance into body surface or body cavities). the function of Hormones is to maintain homeostasis, response to environmental stimuli, and regulate growth, development and reproduction. Also control the appearance of characteristics that distinguish child from adult Local regulators: secreted molecules over short distant and reach target cells solely by diffusion. function in communicating between immune cells, blood pressure, nervous system, and reproduction. function in paracrine (target cell lie near the secreting cell) and autocrine signaling (secreting molecules act on the secreting cell itself)
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Neurotransmitters: at synapses, secreted molecules that diffuse a very short distance to bind receptors on target cells; central to sensation, memory, cognition and movement In neuroendocrine signaling, Neurohormones are molecules that are secreted by neuron found in the brain and travel through bloodstream to reach target cell, e.g - ADH (critical to kidney function and water balance) Pheromones: chemicals that are released into the external environment; function in marking trails leading to food, defining territories, warning of predators, and attracting potential mates In chemical compostion, hormones are divided into 3 groups: - polypeptides: insulin; made up of 2 polypeptide chains; formed by cleavage of longer protein chain - amines: epinephrine and thyroxine; synthesized from a single AA (tyrosine or tryptophan) - steroids: cortisol; lipid containing 4 fused carbon rings; insulin and epinephrine are water soluble located on the cell surface determine by radioactive hormones and secreted by exocytosis; thyroxine and cortisol is lipid soluble located inside the target cell proved by experimenting estrogen and diffuse out adn travel in the bloodstream Melanocyte-stimulating hormones (MSH) controls location of pigment granules in skin cells receptor location is several diff between the response pathways
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Ch 45 - Ch 45 (entire chapter: hormones for which specific...

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