Endocrine System Flashcards
What are the three zones in the adrenal cortex?
Zona glomerulosa
Zona fasciculata
Zona reticularis
What happens at the zona glomerulosa?
Mineralocorticoids —> Aldosterone
What happens in the zona fasciculata?
Glucocorticoids- —> cortisol
What happens at the zona reticularis?
Androgens—> dehydroepiondrosterone
What cell is present in the adrenal medulla?
Chromaffin cells
What happens in chromaffin cells?
Catecholanines—> adrenaline/ noradrenaline
What is aldosterone responsible for?
Sodium and water homeostasis
Sodium reabsorbtion
How are aldosterone hormones secreted?
Stimulates by increased plasma and RAAS system
What is the body’s reaction to more aldosterone?
Sodium reabsorption increases in the kidney
Water reabsorption is increased in the kidneys
Potassium excretion is increased in the urine
What disease is as a cause from aldosterone deficiency?
Hypoaldosteronism
What disease apis as a cause from an excess of aldosterone?
Primary hyperaldosteronism (Conns syndrome)
What is dehydroepiandrosterone (DHEA)?
Steroid hormone that regulates the development of male characteristics
How is androgen secreted?
Regulated by the level of ACTH
What happens when there is a deficiency of androgens?
Hypoandrosteronism (loss of muscle)
What happens when there is an excess of androgens?
Excess hair, masculation
What is cortisol?
Steroid hormones that regulates the glucose metabolism
How is cortisol secreted?
Regulates by the level of ACTH/ CRH
What happens when there is an excess of cortisol?
Cushing disease
What happens when there is a deficiency of cortisol?
Addisons disease
What does antidiuretic hormone (ADH)/ Argonne vasopressin(AVP) do?
Increase permeability and therefore reabsorption of water
How are ADH/AVP secreted?
Stimulated by hypovolaemia, hyperosmolarity and hypotension
What happens when there is a deficiency of ADH/AVP?
Diabeties insipidus
Polyceria
Polydipsia
Pituitary DI= inadequate release of ADH
Nephrotic DI= dysfunction of receptors in collecting duct
What happens when there is an excess of ADH/AVP?
Syndrome of inappropriate ADH secretion (SIADH)
CNS pathologies, malignancy, CNS drugs
Retention of water in the body
Hyponaterimia
What enzymes are involved in insulin?
Pro convertase 1
Proconvertase 2
Carboxypeptidose 4
What is the function of insulin?
Lowers blood glucose
What are the 5 differ t intercellular messenger systems?
Paracrine
Autocrine
Endocrine
Neuroendocrine
Neurotransmission
What is involved in paracrine messenger systems?
Secreting cells secrete to target cells in close contact
What is involved in autocrine messenger systems?
Secreting cells secreted chemicals are taken back by the secreting cells
What is involved in endocrine messenger systems?
Secreting cells secrete to blood vessels and it’s taken to target cell
What is involved in neuroendocrine messenger systems?
Nerve to target cell
What is involved in neuroteansmission messenger systems?
Nerve to nerve
How do hormones reach target cells?
Glands secrete hormones directly into blood stream
Carried to target cells (away from endocrine gland)
What are the 4 different types of hormones?
Peptide hormones
Steroidal hormones
Tyrosine containing hormones
Eicosanoids hormones
What is the chemical structure of peptide hormones?
Chains of amino acids
What is the synthesis of peptide hormones?
Like any protein synthesis
How are peptide hormones realeased?
Requires stimuli ( exocytosis)
How are peptide hormones transported?
Hydrophilic
Freely circulating in blood
No plasma protein bonding
What is the chemical structure of steroidal hormones?
Cholesterol as the base
How is the steroidal hormones synthesised?
Like any steroidal synthesis
How are steroidal hormones released?
Stimulus increases enzyme activation
Simple diffusion across membrane
How are steroidal hormones transported?
Lipophilic
Binds with plasma protein
What is the chemical structure of tyrosine containing hormones?
Tyrosine as the base
How are tyrosine containing hormones synthesised?
Tyrosine creates thyroxine and epinephrine separately
How are tyrosine containing hormones released?
Stimulus required
Simple diffusion across membrane
How are tyrosine containing hormones transported?
Lipophilic
Binds with plasma protein
What is the chemical structure of eicosanoids?
Polyunsaturated fatty acid derivatives
How are eicosanoids synthesised?
Precursor = arachidonic acid
Enzymes= lipase dictates the production
How are eicosanoids released ?
Stimulus required
Poorly diffuse through cell membrane
What does hyper-secretion show?
Tumour or immunological factors
What does hyposecretion show?
Genetic, immunological attack, destruction by disease, surgical removal
What is shown when there is an ectopic disorder?
ACTH producing tumour
CRH low
High ACTH
What is shown when there is a primary defect?
High trophic hormone
Low hormone
Problem in peripheral endocrine gland
What is shown when there is secondary defect?
High releasing hormone
Low trophic hormone
Problem in the anterior pituitary
What are the steps of diagnosing endocrine disorders?
1) signs and symptoms
2) hormone level
3) imaging
What is the treatment option for hyposecretion?
Replace hormone
What is the treatment for hyper secretion?
Block synthesis
What is the treatment for impaired cell responsiveness?
Drug to enhance cellular response
What is the treatment for a tumor?
Surgery or radiotherapy
What is the pituitary gland ?
A small pea-sized gland located at the base of your brain below your hypothalamus
What three lobes are present in the pituitary gland?
Anterior pituitary
Intermediate pituitary
Posterior pituitary
What hormones are secreted form the anterior pituitary?
Somatotropin (GH)
Prolactin (PRL)
Thyrotropin (TSH)
Gonatropins —> (FSH) (LH)
Adeenocorticotrophic hormone (ACTH)
What is stored and released on the posterior pituitary?
Oxytocin
ADH (vasopressin)
What is tropic?
Turning - affecting the activity of an endocrine gland
What is trophic?
Feed/grow- promote growth, tissue integrity
How is somatotropin stimulated?
By a drop in blood glucose
What is the direct function of somatotropin?
Stimulate: lipolysis, blood glucose, gluconeogenesis, protein synthesis
Restrict: glucose uptake
What is the indirect function of somatotropin?
Growth (insulin from liver)
What influences somatotropin (GH) release?
Blood glucose, free fatty acids and amino acid levels
What is the outcome of excess somatotropin?
Gigantism (children)
Acromegaly (adults)
What is the outcome of insufficient somatotropin?
Dwarfism
What is the function of thyroid hormone (T3)?
Basal metabolic rate
Growth and development
Synergistic effect with sympathetic/catecholamine
What happens when there is excess of thyroid hormone (T3)?
Nodular (hypersecretion)
graves disease(primary abnormal levels of thyroid-stimulating immunoglobin)(t3,t4 is high but tsh is low)
secondary defect to excess to anterior pituitary secretion (increase in t3,t4 and tsh)
What happens when there is insufficient of thyroid hormone (T3)?
Diffuse (hyposecretion)
hashimotos disease(primary failure of thyroid gland)(increase in tsh but decrease in t3 and t4)
secondary disease to hypothalmic or anterior pituitary failure (decrease in t3,t4 and tsh)(no goitre)
What is the function of prolactin?
Stimulates lactation in mammary glands
Promotes growth and development of the breast
What is the outcome of excess prolactin?
Hyperprolactinaemia
Loss of fertility/libido ,galactorhoea
