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BioChem2 lecture 2 Hormones

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winniesmith1's version from 2017-02-22 13:45

Section 1

Question Answer
What are the 3 components of the endocrine system?1. Host gland 2. Hormones 3. Target (receptor) cells or organs
Describe endocrine glandsDuctless - Hormones diffuse into the blood for transport. Secretion adjusts rapidly to changing body functions
Describe exocrine glands Ducts - lead directly to the specific compartment or surface that requires the hormone. • nervous system controls almost all exocrine glands.
What are the endocrine organsHypothalamus, pituitary, thyroid/ parathyroid, thymus, adrenal, pancreas, ovaries, testes glands
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Section 2

Question Answer
Describe steroid hormones - Lipid soluble - Diffuse through cell membranes; receptors located within cell. - Chemical structure is derived from or is similar to cholesterol. -w Secreted by adrenal cortex, ovaries, testes, placenta.
Describe the action steroid hormones 1 - Diffuse through the membrane 2 - Binds & activates intracellular receptor. 3 - Steroid-Receptor complex binds to DNA receptor protein 4 - Activates a gene. 5 - Gene transcribed into messenger RNA. 6 - mRNA goes to the ribosomes 7 -Translate mRNA into protein.
Describe non steroid hormones -Non-lipid soluble -Cannot diffuse through cell membranes; receptors located on cell membrane. -Two types: amino acid derivatives and protein or peptide hormones.
Describe the action of non steroid hormones 1 - Hormone Receptor Protein Hormone binds to the plasma membrane at a specific site Receptor protein changes shape and activates G protein 2 - Effector Enzyme G protein complex activates adenylate cyclase. Adenylate cyclase breaks GTP to GDP. Generates second messenger cyclic-AMP from ATP. 3 - Second Messenger cyclic-AMP moves around the cell triggering chemical reactions with protein kinases. 4 - Metabolic Responses Triggered
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Section 3

Question Answer
How is hormone release controlled Plasma levels of specific hormones fluctuate. -Secretion is regulated by a negative feedback system. -Cells can also alter their number of hormone receptors via down- or up-regulation
What is up-regulation—Increase in number of cell receptors; more hormone can bind to the cell and lower concentrations of the hormone remain in the blood plasma
What is down-regulation—Decrease in number of cell receptors; less hormone can bind to the cell and higher concentrations of the hormone remain in the blood plasma
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Section 4

Question Answer
Describe the structure of the pituitary gland Has a posterior lobe and an anterior lobe (looks like two walnuts hanging on a string).
What hormones does the posterior lobe secrete-Antidiuretic hormone (ADH) -Oxytocin
What hormones does the anterior lobe secrete-Growth hormone (GH) -Prolactin(PRL) -4 hormones that affect other endocrine glands -(LH, FSH, TSH, ACTH)
What does ADH do?Helps conserve body water.
How does ADH work?1) Muscular activity promotes sweating. 2) This causes loss of blood plasma (causes decrease in hemoconc. and increased blood osmolarity. 3) this stimulates the hypothalamus. 4) which stimulates the posterior pituitary gland. 5) which scretes ADH. 6) ADH acts on kidneys, increases permeability of renal tubules & collecting ducts (more water reabsorbed). 7) plasma vol increases, osmolarity decreases.
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Section 5

Question Answer
What do growth hormones do? Promotes muscle growth and hypertrophy by facilitating amino acid transport -Directly stimulates fat metabolism (lipolysis) - Levels are elevated during aerobic exercise in proportion to exercise intensity
What are the hormones of the thyroid gland- Triiodothyronine (T3) and Thyroxine (T4) . - Calcitonin
Where is the thyroid gland?Wrapped around the anterior portion of the larynx.
What does T3 and T4 do?- Increase protein and enzyme synthesis -Increase size and number of mitochondria in cells -Promote rapid cellular uptake of glucose - Enhance glycolysis and glycogenesis -Increase FFA availability for oxidation
What does calcitonin do?Metabolizes calcium
What does the parathyroid gland do?produces parathyroid hormone (PTH)
What does the PTH do?regulates plasma calcium concentration and plasma phosphate by targeting the bones, intestines, and kidneys.
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