Hormones and metabolism

Option D5

Essential idea: Hormones are not secreted at a uniform rate and exert their effect in low concentrations.


D.5.U1 Endocrine glands secrete hormones directly into the bloodstream

Diagram endocrine gland

D.5.U2 Steroid hormones bind to receptor proteins in the cytoplasm of the target cell to form a receptor-hormone complex

Steroid binding receptor in cytoplasm diagram
Hormone-receptor complex explained

D.5.U3 The the receptor-hormone complex promotes the transcription of specific genes

Steroid and transcription diagram
Steroid transcription explained

D.5.U4 Peptide hormones bind to receptors in the plasma membrane of the target cell

Peptide hormone binds receptor

D.5.U5 Binding of hormones to membrane receptors activate a cascade mediated by a second messenger inside the cell

Production of bile salts

Cascade of reactions explained

D.5.U6 The hypothalamus controls hormone secretion by the anterior and posterior lobes of the pituitary gland

Hypothalamus control of the anterior and posterior pituitary glands

D.5.U7 Hormones secreted by the pituitary control growth, developmental changes, reproduction and homeostasis

Pituitary gland hormones and function table


D.5.A1 Some athletes take growth hormones to build muscles

Athletes and growth hormone use

D.5.A2 Control of milk secretion by oxytocin and prolactin

Milk production control prolactin and oxytocin

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