BIOL 1020 Lecture Notes - Lecture 3: Adrenal Medulla, Adrenal Gland, Cell Membrane
24 Dec 2015
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Binding of the hormone has a direct effect of the level of transcription. Steroid hormones: small, lipid-soluble molecules made from cholesterol, can pass through the plasma membrane. Enters the nucleus: bind to receptors inside the cell (dna, transcribe mrna, direct gene activation. Uses a different mechanism to reduce and fix. Direct gene activation steroid hormones at the site. Neural stimuli: in isolated cases only, nerve fibers stimulate hormone release. Sympathetic nervous stimulation of the adrenal medulla to release noradrenalin and adrenalin during periods of stress. Control of release: internal or external stimulus triggers hormone secretion, leads to increase levels of hormones in the body, rising levels inhibit further hormone release, endocrine. Release hormones into the blood or lymph. Hypothalamus, pituitary, tyroid, adrenal gland: exocrine. Release their products at the body"s surface or into the body cavities. Hypothalamus: receives information from nerves, sends nervous and endocrine signals, uses pituitary gland to relay direction (hormones) to other glands.
