4D 1.4 hormonal control Flashcards by Rohmat Ali

Q1 what are the 4 types of extracellular communication

Paracrine secretion

Neurotransmitter secretion

Hormonal secretion

Neurohormone secretion

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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

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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.

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Q4 which hormones are responsible for regulating metabolism, water and electrolyte balance

Vasopressin and aldosterone

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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

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Q6 which hormone is responsible for inducing adaptive changes to help the body cope with stressful situations.

Adrenaline and cortisol

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Q7 which hormone is responsible for Controlling sexual differentiation and reproduction

Testosterone and progesterone

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Q8 which hormone is responsible for regulating red cell production

Erythropoietin (found in the kidney)

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Q9 give an example where a single endocrine gland can produce multiple hormones

Anterior pituitary gland

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Q10 give an example of a hormone that can be secreted by more than one endocrine gland

Somatostatin

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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

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Q12 give an example of a chemical messenger which can be both a hormone or a neurotransmitter

Noradrenaline

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Q13 give an example of an organ which performs non-endocrine functions as well as secreting hormones

Testes

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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

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Q15 give examples of a tropic hormones released from the anterior pituitary gland

FSH/LH, ACTH, TSH (FLAT)

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Q16 give example of non-tropic hormones

Insulin, growth hormone, prolactin

These hormones effect target cells.

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Q17 what is the function of trophic hormones

Stimulate and maintain their endocrine gland (TSH)

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Q18 which hormones are steroid hormones

Aldosterone

Cortisol

Progesterone

Testosterone

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Q19 which hormones are amines

Adrenaline

Noradrenaline

Thyroxine

Triiodothyronine

Dopamine

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Q20 which hormones are peptide classification

ACTH

ADH

Calcitonin

Glucagon

Insulin

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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

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Q22 how are peptide hormones exported from the cell

Exocytosis

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Q23 what is the precursor for peptide hormones

Prephormones

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Q24 where are the prehormones activated

Enzymes in the ER prune the prehormones to active hormones

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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 2^nd 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 3^rd stage of the thyroid hormone synthesis

Iodination of thyroglobulin occurs in the follicular lumen

Q10 what is the 4^th 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 6^th stage of the thyroid hormone synthesis

Proteolysis of the iodinated thyroglobulin, forming T4 and T3

Q13 what is the 7^th 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

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