PHGY 210- Endocrinology Exam Study
Guide
Long distance communication - Answer - Communication between cells that are not in
contact is achieved through a number of chemical substances that interact with
receptors on distant target cells
- Signals on receptor cells lead to a number of physiological effects
Types of signalling: Long term - Answer - Endocrine
- Neuroendocrine
Endocrine signalling - Answer - Involves the release of a hormone into the circulation by
an endocrine gland
- Released hormones by anterior pituitary reach a target site via blood vessels, where
multiple physiological processes occur
Neuroendocrine signalling - Answer - The source of the signal is the neuron
Types of signalling short term - Answer - Paracrine
- Autocrine
Paracrine signalling - Answer A type of cell-cell communication where a cell produces a
signal to induce changes in nearby cells
Autocrine signalling - Answer - Cell releases a hormone and the cell itself has the
receptor
Steps in hormone communication - Answer 1. Synthesis of the hormone by endocrine
cells (or neurons in the case of neuroendocrine signalling)
2. Release of the hormone by endocrine cells/neurons
3. Transport of the hormone or neurohormone to the target site by the blood stream
4. Detection of the hormone or neurohormone by a specific receptor protein on the
target cells
5. A change in cellular metabolism triggered by the hormone-receptor interaction
6. Removal of the hormone which often terminates the cellular response
Examples of classical endocrine organs - Answer - Hypothalamus and pituitary
- Thyroid and parathyroid
,- Heart
- Adrenal glands
- Pancreas
- Gonads
Hypothalamic-pituitary signalling - Answer - Endocrine signalling between the
hypothalamus and pituitary via blood vessels in the pituitary stalk
Hypothalmic-hypophyseal signalling is between the ____ and ____ - Answer -
Hypothalamus and anterior pituitary
Two types of hormones based on function - Answer - releasing or inhibiting
Classes of hormones based on structure - Answer Glycoproteins- sugar coating
Polypeptide- short protein
Steroids - small molecules
Amines - small molecules
Ionic clacium - acts like a hormone (calcium sensing receptor)
Synthesis of protein hormones - Answer - information necessary for synthesis is
encoded within a gene
- The genes encode the mature polypeptide/glycoprotein
- Intitially synthesized as preprohormones, later the prepro-sequence is cleaved off
Examples of steroid hormones - Answer - Cortisol
- Aldosterone
- Estradiol
- Testosterone
- 4 ring steroid backbone
Structure of thyroid hormones - Answer - Derived from tyrosine
- Contains iodine
- Two forms of steroid hormones: T3 and T4
Which form of thyroid hormone binds to hormone receptors - Answer T4
What are the properties of hormone receptors? - Answer - Specificity: recognition single
of a hormone or hormone family
, - Affinity: binding hormone at its physiological concentration
- Saturability: a finite number of receptors
- Measurable biological effect: measurable biological response to the interactions of the
hormone and its receptor
How can receptors be regulated? - Answer - Upregulated by increasing the activity or
synthesis in response to hormone
- Downregulated by decreasing their activity or synthesis in response to a hormone
Three mechanisms by which a hormone can exert effects on target cells - Answer 1.
Direct effect on function at the cell membrane
2. Intracellular effect mediated by second messenger systems
3. Intracellular effect mediated by genomic or nuclear action
Example of second messenger systems - Answer - G protein coupled receptor coupled
to adenylyl cyclase that converts ATP to cAMP that interacts with a kinase that can turn
the protein on or off
Example of genomic or nuclear action - Answer - Steroids and steroid-like molecules
look like cholesterol and can enter the cell
- Steroid hormones bind to a specific receptor, synthesizes a protein in the nucleus,
leading to altered function
Only hormone system that is regulated by positive feedback loops - Answer Female
reproductive system
Negative feedback - Answer The excess of hormone, or excess hormonal activity, leads
to a diminution of hormone secretion
Positive feedback - Answer A deficiency of hormone leads to an increase in hormone
secretion
Anatomy of the pituitary gland - Answer - 2 distinctly different tissues
- Anterior pituitary: Endocrine tissue
- Posterior pituitary: Neural tissue
- Stalk connecting the pituitary to brain
What hormones are synthesized by the posterior pituitary - Answer - Oxytocin and
vasopressin
- Short peptides
Guide
Long distance communication - Answer - Communication between cells that are not in
contact is achieved through a number of chemical substances that interact with
receptors on distant target cells
- Signals on receptor cells lead to a number of physiological effects
Types of signalling: Long term - Answer - Endocrine
- Neuroendocrine
Endocrine signalling - Answer - Involves the release of a hormone into the circulation by
an endocrine gland
- Released hormones by anterior pituitary reach a target site via blood vessels, where
multiple physiological processes occur
Neuroendocrine signalling - Answer - The source of the signal is the neuron
Types of signalling short term - Answer - Paracrine
- Autocrine
Paracrine signalling - Answer A type of cell-cell communication where a cell produces a
signal to induce changes in nearby cells
Autocrine signalling - Answer - Cell releases a hormone and the cell itself has the
receptor
Steps in hormone communication - Answer 1. Synthesis of the hormone by endocrine
cells (or neurons in the case of neuroendocrine signalling)
2. Release of the hormone by endocrine cells/neurons
3. Transport of the hormone or neurohormone to the target site by the blood stream
4. Detection of the hormone or neurohormone by a specific receptor protein on the
target cells
5. A change in cellular metabolism triggered by the hormone-receptor interaction
6. Removal of the hormone which often terminates the cellular response
Examples of classical endocrine organs - Answer - Hypothalamus and pituitary
- Thyroid and parathyroid
,- Heart
- Adrenal glands
- Pancreas
- Gonads
Hypothalamic-pituitary signalling - Answer - Endocrine signalling between the
hypothalamus and pituitary via blood vessels in the pituitary stalk
Hypothalmic-hypophyseal signalling is between the ____ and ____ - Answer -
Hypothalamus and anterior pituitary
Two types of hormones based on function - Answer - releasing or inhibiting
Classes of hormones based on structure - Answer Glycoproteins- sugar coating
Polypeptide- short protein
Steroids - small molecules
Amines - small molecules
Ionic clacium - acts like a hormone (calcium sensing receptor)
Synthesis of protein hormones - Answer - information necessary for synthesis is
encoded within a gene
- The genes encode the mature polypeptide/glycoprotein
- Intitially synthesized as preprohormones, later the prepro-sequence is cleaved off
Examples of steroid hormones - Answer - Cortisol
- Aldosterone
- Estradiol
- Testosterone
- 4 ring steroid backbone
Structure of thyroid hormones - Answer - Derived from tyrosine
- Contains iodine
- Two forms of steroid hormones: T3 and T4
Which form of thyroid hormone binds to hormone receptors - Answer T4
What are the properties of hormone receptors? - Answer - Specificity: recognition single
of a hormone or hormone family
, - Affinity: binding hormone at its physiological concentration
- Saturability: a finite number of receptors
- Measurable biological effect: measurable biological response to the interactions of the
hormone and its receptor
How can receptors be regulated? - Answer - Upregulated by increasing the activity or
synthesis in response to hormone
- Downregulated by decreasing their activity or synthesis in response to a hormone
Three mechanisms by which a hormone can exert effects on target cells - Answer 1.
Direct effect on function at the cell membrane
2. Intracellular effect mediated by second messenger systems
3. Intracellular effect mediated by genomic or nuclear action
Example of second messenger systems - Answer - G protein coupled receptor coupled
to adenylyl cyclase that converts ATP to cAMP that interacts with a kinase that can turn
the protein on or off
Example of genomic or nuclear action - Answer - Steroids and steroid-like molecules
look like cholesterol and can enter the cell
- Steroid hormones bind to a specific receptor, synthesizes a protein in the nucleus,
leading to altered function
Only hormone system that is regulated by positive feedback loops - Answer Female
reproductive system
Negative feedback - Answer The excess of hormone, or excess hormonal activity, leads
to a diminution of hormone secretion
Positive feedback - Answer A deficiency of hormone leads to an increase in hormone
secretion
Anatomy of the pituitary gland - Answer - 2 distinctly different tissues
- Anterior pituitary: Endocrine tissue
- Posterior pituitary: Neural tissue
- Stalk connecting the pituitary to brain
What hormones are synthesized by the posterior pituitary - Answer - Oxytocin and
vasopressin
- Short peptides
