Hormones Flashcards
Communication by hormones:
endocrine
Information Processing
Signal transduction:
- Sensory cell (have signal receptors)
- receives external signal and transduces information to an internal signal
- Cell to cell signal (hormones)
- released by the sensory cell travels throughout plant
- Target cell (have hormone receptors)
- receives signal and initiates response
5 Chemical Signals
- Neural signals: diffuse a short distance between neurons
- Neuroendocrine signals: are hormones released from neurons
- Endocrine signals: are hormones carried between cells by blood or other body fluids
- Paracrine signals: diffuse locally and act on nearby cells
- Autocrine signals: act on the same cell that secretes them
Integration of hormones and neurons:
Opportunity for feedback:
Opportunity for feedback: feedback inhibition (negative feedback) → homeostasis
What are the 3 pathways and what do they each have?
- Endocrine pathway: has hormone
- Neuroendocrine pathway: has neurohormone
- Neuroendocrine-to-endocrine pathway: has both neurohormone and hormone
Actions of Hormones:
2 fundamentally different pathways are:
water soluble (hydrophilic) hormones and water insoluble (lipophilic hormones)
Hydrophilic hormones are and have?
Hydro: Peptides and Polypeptides, Amino Acid Derivatives
Has a Membrane receptor: intracellular signal transduction (second messengers)
Lipophilic hormones are and have?
Lipo: Steroids
Has a intracellular receptor (nuclear receptor)
Steroid Hormones examples:
- cortisol: stress response
- anabolic steroids - muscle growth
- sex steroids: estrogenes, testosterone
- Aldosterone ; Na+ resorption in kidney
other water insoluble (lipophilic) hormones (same mechanism)
- retinoid acid
- thyroid hormone
- Prostaglandins (paracrine acting)
- juvenile hormone (insects)
Actions of Steroid hormones
Example used for answers: hormone stimulates gene expression (up-regulation)
The steroid hormone will…
The steroid hormone will…
- diffuse through plasma membrane
- in cytosol, bound by receptor
- move into nucleus
- hormone/receptor complex binds to response element
- turn on gene expression
- proteins are translated in the cytosol
Some hormone suppress gene expression: binding to element stops what? this leads to what
Transcription
- So it will turn off gene expression
- and protein are not translated in the cytosol
What are target cell for steroid hormone:
- Target cell for steroid hormone: cells that have intracellular receptor
- Hormones act in extremely small amounts
- very strong binding to receptors
- often bind as dimers:
What are the two identical and different proteins/hormones
Two identical proteins/hormones: Homo-dimers
Two different proteins/hormones: hetero-dimers
Insect example: Insects remodels to emerge as adult moth
The growth by molting is controlled by which hormone:
Which hormone causes larva-larva molting
- larva grow by molting: controlled by hormones:
- ecdysone: triggers each molting
- Juvenile hormone: causes larva-larva molting