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13 Cards in this Set
- Front
- Back
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What are the three main types of hormones and what is the most common?
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Peptide - eg ADH, FSH
Amines - eg dopamine Steroids - modified amino acid residues, hydrophilic so can pass through lipid bilayer, made from cholesterol eg cortisol Peptide hormones are the most common |
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What is the central axis?
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The hypothalamic pituitary axis is a complex set of direct influences and feedback interactions between the hypothalamus, the pituitary gland and the adrenal glands
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Describe the pituitary gland
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Pea size endocrine gland
The pituitary fossa is situated in the sphenoid bone in the middle cranial fossa at the base of the brain Sits on sella turcica Linked to hypothalamus by infundibulum Secretes 9 hormones to maintain homeostasis Has adenohypothysis (anterior) and neurohypophysis (posterior) |
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Give the three embryological origins of hypothalamus, anterior and posterior pituitary gland
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Hypothalamus - Develops from neuroectoderm
Anterior - Develops from Rathkes pouch Posterior - Derives from envagination of ventral hypothalamus |
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Give the main hormones that the anterior and posterior pituitary release.
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A - LH, ACTH, TSH, GH, prolactin
P - ADH (vasopressin), oxytocin |
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Describe the main effects of pituitary tumours
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- 30% are non-functioning
- Hypersecretion eg acromegaly w/ GH - Hormone deficiency states - Headaches and visual loss or field defects due to space occupation and compression on optic chiasm |
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What does hyperprolactinaemia cause and how is it treated?
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It causes galacthorhea (spontanous milk production), infertility, impotence and headaches.
It is treated with a dopamine agonist because dopamine inhibits prolactin seretion |
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Describe the main differences between hyperthyroidism and hypothyroidism
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- Hyper (over activity) caused by Graves disease. LOW TSH
- Hypo (underactivity) caused by autoimmune Hashimoto's or idiopathic atrophy. RAISED TSH |
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What are the clinical features of Hyper thyroidism?
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- Weight loss
- Diarrhoea - Tremor - Tacchycardia - Fatigue - Weakness - Sweaty and warm |
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What are the clinical features of hypothyroidism?
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- Weight gain
- Bradycardic - Constipation - Goitre - Cold - Dry skin |
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What are the different layers of the cortex of the adrenal gland and what do they produce? (starting from the outer layer)
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- Zona Glomerulosa (mineralocorticoids)
- Zona Fasiculata (glucocorticoids) - Zona Reticularis (sex steroids) |
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What are mineralocorticoids and glucocorticoids?
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MC - involved in fluid/sodium balance. eg aldosterone influenced by RAS acts on nephrons to conserve Na+.
GC - involved in glucose homeostasis. eg cortisol influenced by ACTH from anterior pituitary released in response to stress and low glucose by gluconeogenesis. |
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What is Cushings syndrome?
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Caused by a pituitary tumour that causes too much ACTH to be produced and hence too much cortisol from the zona fasiculata of the adrenal cortex. Clinical features include moon face, big belly and pigmentation.
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