4D 1.4 hormonal control Flashcards
Q1 what are the 4 types of extracellular communication
Paracrine secretion
Neurotransmitter secretion
Hormonal secretion
Neurohormone secretion
Q2 what is a hormone
Hormone: a chemical mediator that is secreted by an endocrine tissue or gland into the blood, which transports it to its target cells
Q3 what is the difference between paracrine and endocrine actions
Paracrine: describes hormone action where hormones are released from cells and bind to receptor on nearby cells and affects their function.
Endocrine responses are slow and long because the hormone needs to be filtered out of the blood before it can take effect.
Q4 which hormones are responsible for regulating metabolism, water and electrolyte balance
Vasopressin and aldosterone
Q5 which hormone is responsible for regulation of nutrient supply
Insulin, glucagon, and glucocorticoid, play important roles in controlling the rate of protein degradation and, therefore, the rate of glucose production by the liver
Q6 which hormone is responsible for inducing adaptive changes to help the body cope with stressful situations.
Adrenaline and cortisol
Q7 which hormone is responsible for Controlling sexual differentiation and reproduction
Testosterone and progesterone
Q8 which hormone is responsible for regulating red cell production
Erythropoietin (found in the kidney)
Q9 give an example where a single endocrine gland can produce multiple hormones
Anterior pituitary gland
Q10 give an example of a hormone that can be secreted by more than one endocrine gland
Somatostatin
Q11 give an example of a hormone that has more than one type of target cell and therefore can induce more than one type of effect
Vasopressin – regulate arterial blood pressure and renal tubules for water reabsorption
Q12 give an example of a chemical messenger which can be both a hormone or a neurotransmitter
Noradrenaline
Q13 give an example of an organ which performs non-endocrine functions as well as secreting hormones
Testes
Q14 What is the classification given when a released hormone from the anterior pituitary gland has a direct effect on an endocrine gland?
A tropic hormone
Q15 give examples of a tropic hormones released from the anterior pituitary gland
FSH/LH, ACTH, TSH (FLAT)
Q16 give example of non-tropic hormones
Insulin, growth hormone, prolactin
These hormones effect target cells.
Q17 what is the function of trophic hormones
Stimulate and maintain their endocrine gland (TSH)
Q18 which hormones are steroid hormones
Aldosterone
Cortisol
Progesterone
Testosterone
Q19 which hormones are amines
Adrenaline
Noradrenaline
Thyroxine
Triiodothyronine
Dopamine
Q20 which hormones are peptide classification
ACTH
ADH
Calcitonin
Glucagon
Insulin
Q21 what does the solubility of a hormone determine
How the hormone is processed by the endocrine cell
How the hormone is transported in the blood
How the hormone exerts its effects at the target cell
Q22 how are peptide hormones exported from the cell
Exocytosis
Q23 what is the precursor for peptide hormones
Prephormones
Q24 where are the prehormones activated
Enzymes in the ER prune the prehormones to active hormones
Q25 what is the common precursor for all steroid hormones
Cholesterol
Q26 what must occur for the cholesterol to synthesis in to steroid hormones
Series of enzymatic reactions
Q27 what determines the rate of release of steroid hormones
Dependant on how fast production is
Q28 are steroids stored in the body
No, steroid hormones are made and released on demand
Q29 all hormones are carried by blood, which hormones are dissolved in the blood.
Peptide hormones
Q30 are hydrophilic peptides and catecholamines soluble in lipid
Poorly soluble in lipid
Q31 where do hydrophilic peptides bind to
Receptors on the outer pm surface of the target cell
Q32 where do lipophilic steroids and thyroid hormones bind to
Specific receptors located inside the target cell
Q33 which hormones directly alter activity of intracellular enzymes
Hydrophilic hormones
Q34 which hormones directly cause formation of new intracellular enzymes
Lipophilic hormones
Q35 what are the solubility of the following
Peptides
Catecholamines
Thyroid hormones
Steroids
Peptides – hydrophilic
Catecholamines – hydrophilic
Thyroid hormones – lipophilic
Steroids – lipophilic
Q36 what are the secretion method of the following
Peptides
Catecholamines
Thyroid hormones
Steroids
Peptides – exocytosis
Catecholamines – exocytosis
Thyroid hormones – endocytosis
Steroids – simple diffusion
Q37 what are the receptor site of the following
Peptides
Catecholamines
Thyroid hormones
Steroids
Peptides – surface of target cell
Catecholamines – surface of target cell
Thyroid hormones – inside target cell
Steroids – inside target cell
Q38 the effective plasma concentration of free, biologically active hormone can depend upon
Hormones rate of secretion in to the blood
Rate of metabolic activation or conversion (T4 > T3)
Binding to plasma proteins
Rate of removal from blood
Q39 negative feedback control, neuroendocrine reflexes and diurnal are examples of what
General mechanisms controlling secretion
Q40 hyposecretion comes in two forms primary and secondary, describe both forms.
Primary – abnormality with gland (genetic, dietary, chemical or toxic, immunologic, disease, iatrogenic, idiopathic)
Secondary – endocrine is normal but secreting too little because of a deficiency of its tropic hormone.
Treatment – replacement therapy
Q41 hypersecretion comes in two forms primary and secondary, describe both forms
Primary – defect lies I gland itself (tumours)
Secondary – excessive stimulation from outside (immunologic factors)
Treatment – remove tumour, drugs inhibit secretion
Q1 growth from fertilised ovum to the adult is dependent on
Genetic contribution
Nutrition
Multiple hormones regulate linear growth
Q2 which growth hormones regulate linear growth
GH, IGF-1, IGF-2, insulin, TH, glucocorticoids, androgens and estrogens
Q3 where is leptin made
Leptin is a protein made almost exclusively in adipocytes
Q4 how does leptin regulate CNS feeding behaviour
Crosses the BBB to modulate specific neurons in the arcuate nucleus of the hypothalamus that control feeding behaviour
Q5 what is the function of ghrelin
Is a hormone synthesised and released from the cells in the gastric mucosa in response to fasting
It promotes appetite
Circulating levels are low in lean humans
Q6 No cell membrane receptors exist for thyroid hormones, how do they act on target cells.
Thyroid hormones enter cells through simple diffusion through the plasma membrane and bind on to nuclear receptors and regulate transcription of cell proteins
Q7 what is the first stage of thyroid hormone synthesis
increase activity of the Na/I cotransporter increases iodine trapping
Q8 what is the 2nd stage of thyroid hormone synthesis
Iodine leaves the follicular cell and enters the lumen where it is oxidised from I- to I°
Q9 what is the 3rd stage of the thyroid hormone synthesis
Iodination of thyroglobulin occurs in the follicular lumen
Q10 what is the 4th stage of the thyroid hormone synthesis
conjugation of iodinated tyrosines to form T4 and T3 liked to thyroglobulin
Q11 what is the 5th stage of the thyroid hormone synthesis
Iodinated thyroglobulin enters the follicular cells through endocytosis
Q12 what is the 6th stage of the thyroid hormone synthesis
Proteolysis of the iodinated thyroglobulin, forming T4 and T3
Q13 what is the 7th stage of the thyroid hormone synthesis
secretion of T4 and T3
Q14 which hormone T4 or T3 is more abundant
90% released as T4 and 10% as T3
T3 more active
Liver and kidneys convert T4 in to T3
Q15 how do both hormones T4 and T3 travel in circulation
They are highly bound to plasma proteins (thyroid binding globulin, albumin and transthyretin)
Q16 which hormone T4 or T3 increases the basal metabolic rate greater
T3
Q17 THs increase hepatic (liver) gluconeogenic (production of glucose) activity, by inducing several gluconeogenic enzymes, what will prevent and increase in plasma glucose
Insulin
Q18 thyroid hormones can increase protein synthesis and break protein down by increased proteolysis. What is the condition where muscle is will start to become weak and waste as a result of increase metabolism
Hyperthyroidism
Q19 thyroid hormones provide glycerol for hepatic gluconeogenesis, how
Increased degradation of stored triglycerides in adipose tissue
Q20 what is graves disease
a swelling of the neck and protrusion of the eyes resulting from an overactive thyroid gland.
Q21 what causes graves disease
Caused by abnormal immunoglobulin (TSI thyroid stimulating immunoglobulin) which binds to activates the TSH receptor. Leads to an increased secretion of both T3 and T4.
Q22 what are the symptoms of graves disease
Increased metabolic rate with associated weight loss
Sweating and heat intolerance
A rapid and more forceful heartbeat
Muscle weakness and wasting
Changes in hair growth and skin texture
