Hormonal control

Hormones can be steroids, proteins or tyrosine derivatives (amines)

Amine hormones (Tyrosine derivatives)

• Produced by the adrenal gland, the hypothalamus and the anterior pituitary gland

• Very short duration of action – act as neurotransmitters as well as hormones

Amine hormones

Steroid hormones

• All derivatives of cholesterol• Insoluble in water – travel in plasma bound to plasma proteins• Longer-acting and act INSIDE the cell• Stress, sexuality, SEX

Steroid hormones

• Steroid hormones pass through the cell membrane easily and act on the inside of the cell

• May bind to receptors in cytoplasm OR nucleus

• Steroid hormones alter DNA transcription: they act as ‘transcription factors’…

Peptide/ protein hormones hormones

Peptide and protein hormones

• Soluble in plasma but cannot cross the lipid membrane

• Act on cell surface receptors• Binding with the receptor leads to activtion

of a ‘second messenger’ cascade

H.1.4: Outline the relationship between the hypothalamus and the pituitary gland

Hormones secreted by the hypothalamus/pituitary…

How does the hypothalamus orchestrate the autonomic nervous/endocrine system?

Negative feedback is essential to hypothalamo-pituitary-hormonal control

• Hormones whose secretion is regulated by the hypothalamus and pituitary gland regulate their own release through negative feedback.

• The hormone produced by a peripheral glad will bind to receptors in the hypothalamus and pituitary and inhibit release of ‘tropic’ hormones’

Explain the control of ADH secretion by negative feedback

Thyroid hormone release is controlled by negative feedback…