Download H1 Hormones - TASIS IB Biology

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…