Term
| Where is the pituitary located? |
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Definition
| Sella turcica in sphenoid bone, below the hypothalamus |
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Term
| How is the posterior pituitary connected to the hypothalamus? |
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Definition
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Term
| How is the anterior pituitary connected to the hypothalamus? |
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Definition
| Via the hypothalamo-pituitary portal system (connects two capillaries) |
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Term
| What is the name of the stalk that connects the pituitary to the hypothalamus? |
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Definition
| Infundibulum (hypophyseal stalk) |
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Term
| Where does anterior pituitary tissue originate? |
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Definition
| Rathke’s pouch in the pharynx |
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Term
| What is the median eminence? |
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Definition
| The base of the hypothalamus |
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Term
| What are the two posterior pituitary hormones? |
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Definition
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Term
| What is the function of oxytocin? |
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Definition
| Stimulates milk ejection reflex and stimulates uterine contractions |
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Term
| What is the function of vasopressin? |
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Definition
aka antiduretic hormone
Regulates water reabsorption in collecting ducts |
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Term
| List the hypophysiotropic hormones |
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Definition
Gonadotrophin releasing hormone (GnRH)
Growth Hormone Releasing Hormone (GHRH)
Somatostatin (SS)
Thyrotropin releasing hormone (TRH)
Corticotropin releasing hormone (CRH)
Dopamine |
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Term
| What chemical classification are the trophic hormones? |
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Definition
| All of the trophic hormones are peptides except dopamine |
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Term
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Definition
| Cells in the anterior pituitary that are receptors for the hypophysiotropic hormones |
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Term
| What are the actions of anterior pituitary hormones? |
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Definition
1. Can stimulate an endocrine gland
2. Can have an effect on target tissue directly |
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Term
| What does Adrenocorticotropic hormone (ACTH) do? |
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Definition
| CRH → ↑ ACTH release → adrenal cortex - ↑ cortisol release → target tissues |
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Term
| What does Thyroid-stimulating hormone (TSH, also known as thyrotropin) do? |
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Definition
| TRH → ↑ TSH release → thyroid gland - ↑ thyroid hormone release → target tissue (basal metabolic rate) |
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Term
| What does Follicle-stimulating hormone (FSH) do? |
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Definition
| GnRH → ↑ FSH release → gonads |
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Term
| What does Luteinizing hormone (LH) do? |
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Definition
| GnRH → ↑ LH release → gonads |
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Term
| What does Prolactin do and how is it regulated? |
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Definition
Stimulates breast development and milk production
dopamine inhibits prolactin release |
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Term
| What controls release of growth hormone? |
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Definition
GHRH→ ↑ GH release → liver - ↑ IGF-1 release → target tissues
somatostatin → ↓ GH release |
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Term
| What is the effect of growth hormone? |
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Definition
a. GH stimulates release of IGF-1 from liver
b. GH directly stimulates protein synthesis and lipid and carbohydrate metabolism |
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Term
| Define short-loop inhibition |
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Definition
| Anterior pituitary hormone inhibits hypothalamus hormone secretion |
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Term
| Define long-loop inhibition |
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Definition
| The third endocrine hormone inhibits anterior pituitary and hypothalamus hormone |
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Term
| Define primary hyposecretion and give an example |
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Definition
Abnormality at the gland
a. destruction of the gland (e.g. Type I diabetes)
b. defects in hormone biosynthesis |
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Term
| Define secondary hyposecretion and give an example |
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Definition
Gland is normal but there is too little stimulus from pituitary or trophic hormone
(e.g. Kallman’s syndrome, no LH or FSH release due to GnRH hormones in hypothalamus) |
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Term
| What is a common cause of primary hypersecretion? |
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Definition
| Presence of a hormone-secreting cell tumor |
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Term
| Define secondary hypersecretion and give an example |
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Definition
Gland is normal but there is too much stimulus from pituitary or trophic hormone.
(e.g. hormone secreting tumor in pituitary) |
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Term
| Define the spillover effect and give an example |
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Definition
Excess concentrations of hormone can result in the hormone binding to and activating other classes of receptors.
e.g. Cushing's disease: excess cortisol can activate aldosterone receptors and cause hypertension. |
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Term
| Define hyporesponsiveness |
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Definition
Hormone secretion is normal, but target cell does not respond to hormone
1. Lack of hormone receptors
2. Abnormal receptor-signal transduction
3. Abnormal metabolic activation |
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Term
| Define hyperresponsiveness and give an example |
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Definition
Up-regulation of hormone receptors
e.g. hyperresponse to epinephrine with hyperthyroidism due to up regulation of β-adrenergic receptors |
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