Chapter 9: The Endocrine System Flashcards
Hormones are synthesised in endocrine glands and secreted in
The bloodstream
Hormones act
On specific receptors
Hormones on the membrane of distant cells (specific receptors), referred to as
Target cells
Homeostasis of the internal environment is controlled partly by
The autonomic nervous system and partly by the endocrine system
The release of these hormones varies within a 24 hour period
- Growth hormone
- Thyroid Stimulating hormone
- Adrenocorticotrophic hormone
Levels of which hormones are controlled by negative feedback mechanisms
- Growth hormone
- Thyroid Stimulating hormone
- Adrenocorticotrophic hormone
Level of which hormone is controlled by positive feedback mechanism
Prolactin
Which is the most abundant hormone secreted by the anterior pituitary
Growth hormone
Secretion of which hormone peaks in adolescence
Growth hormone
Circadian rhythm means that regular fluctuations in hormone levels occur over a period of
24 hours
Growth hormone stimulates
- Division of body cells
2. Protein synthesis
T3 is also known as
Tri-iodothyronine
Stimulates uterine smooth muscle contractions during childbirth
Oxytocin
Stimulates secretion of progesterone by the corpus luteum
Luteinising hormone
Regulates tissue metabolism
Growth hormone
Stimulates the adrenal cortex to secrete glucocorticoids
Adrenocorticotrophic hormone
Stimulates reabsorption of water in the kidney tubules
Antidiuretic hormone
Stimulates production of the sperm in the testes
Follicle stimulating hormone
Stimulates milk production in the breasts
Prolactin
Stimulates thyroid activity
Thyroid stimulating hormone
Posterior pituitary hormones are stored in
Axon terminals before their release
Oxytocin and antidiuretic hormone (ADH) are secreted by
The posterior pituitary
Oxytocin acts on
Two different target tissues
ADH secretion is influenced by
Osmoreceptors
The mineral salt iodine is essential for synthesis of
Thyroid hormones
The dietary source for iodine is
Seafood
Thyroid hormones are synthesised as large precursor molecules called
Thyroglobulin
Thyroglobulin are stored in
Follicles filled with colloid
Release of thyroid hormones in the blood is regulated by
Thyroid stimulating hormone
Thyroid stimulating hormone is controlled by
A negative feedback system
Secretion of thyroid hormones begins during fetal life and increases
At puberty and then remains fairly constant throughout life.
Calcitonin, has the opposite effect of
Parathyroid hormone
When increased blood calcium levels are needed, this occurs by
- Increased absorption of calcium in the small intestine
2. Increased absorption of calcium in the renal tubules
What helps to maintain normal levels of calcium in the blood?
- Blood clotting
- Cell membrane
- Neuromuscular activity
- Normal action of many enzymes
An abnormally high metabolic rate could be associated with
Thyroid gland
Secretion is increased by stimulation of the autonomic nervous system
Adrenal medulla
The inner layer of the gland
Adrenal medulla
Secretion is influenced by circadian rhythm
Adrenal cortex
Essential for life
Adrenal cortex
Secretion of sex hormones
Adrenal cortex
Involved in the short term response to stres
Adrenal medulla
Secretion of cholesterol based hormones
Adrenal cortex
Secretion stimulated by ‘fight or flight’ response
Adrenal medulla
Insulin and glucagon exert antagonistic effects on
Blood glucose levels
Insulin tends to lower blood concentrations of
- Glucose
- Amino acids
- Fatty acids
Somatostatin is secreted by
The delta cells of the pancreatic islet
Somatostatin inhibits secretion of
Both insulin and glucagon
Insulin is a polypeptide hormone released by
The endocrine pancreas
Secretion of insulin is stimulated by
High blood glucose levels and parasympathetic stimulation
Factors that decrease the stimulation of insulin include the hormones
- Glucagon
- Adrenaline
- Cortisol
Insulins main function is to
Lower raised blood nutrient level especially glucose but amino acids and fatty acids
Production of milk
Lactation
Antidiuretic hormone
Vasopressin
Childbirth
Parturition
Abnormal milk production
Galactorrhoea
Tingling
Parasthesia
Breathless
Dyspnoeic
No mensturation
Amenorrhoea
Great thirst
Polydipsia
Pregnancy
Gestation
Syndrome caused by hypersecretion of glucorticoid hormones
Cushings
May be caused by a benign tumour of the parathyroid glands that secretes excess parathyroid hormone
Hyperparathroidism
Type of diabetes associated with hypersecretion of antidiuretic hormone
Insipidus
Arises as a complication of type 1 diabetes mellitus when increased insulin requirements are not met
Ketoacidosis
Meaning ‘large extremities’ a condition caused by excessive secretion of growth hormones in adults
Acromegaly
Benign tumour of the adrenal glands that secretes adrenaline and noradrenaline
Phaeochromocytoma
Hypothyroidism in adults
Myxoedema
Consequence of low aldosterone secretion
Hypoaldosteronism
Increased excitability of peripheral nerves caused by hypocalcaemia
Tetany
Enlargement of the thyroid associated with dietary iodine deficiency
Goitre
Diabetes that arises during pregnancy
Gestational
Type of coma associated with type 1 diabetes mellitus, caused by administration of too much insulin in relation to body requirements
Hypoglycaemic
Low blood sodium levels
Hyponatraemia
Protrusion of the eyeballs seen in hyperthyroidism
Exopthalmos
Blood pH lower than normal
Acidosis
A condition caused by excessive secretion of growth hormone in children
Gigantism
Hormones secreted by the testes
Testosterone
Another name for prolactin inhibiting hormone
Dopamine
Large precursor molecule of thyroid hormones T3 and T4
Thyroglobulin
Low blood calcium levels
Hypocalcaemia
Meaning healthcare induced
Iatrogenic
Difficulty in swallowing
Dysphagia
Another name for GHRIH
Somatostatin
High blood potassium levels
Hyperkalaemia
Normal heart rhythm less than 60bpm
Sinus bradycardia
