Endocrine Flashcards
Name the endocrine glands/organs
Pineal gland
Hypothalamus
Pituitary gland
Thyroid
Adrenal glands
Pancreas
Ovaries/ Testes
Which hormone reduces blood sugar?
Insulin
Which hormone increases blood sugar
Glucagon
“Glucose-is-gone”
Which pancreatic cells produce insulin?
Beta cells
(Within islets of langerhans)
Which pancreatic cells produce glucagon?
Alpha cells
(Within islets of langerhans)
How does insulin lower blood-glucose levels?
Interacts with cell membranes to open glut-4 channels, increasing cellular uptake of glucose
Inhibits gluconeogenesis
Increases glycolysis
Glucose storage as fat
What is the role of the endocrine system?
Maintain homeostasis
Control storage and utilisation of energy
Regulation of growth, development and reproduction
Respond to environmental stimuli
What are hormones?
Chemical messengers secreted into the blood. They act only where there is a receptor
What can hormones do?
Change membrane permeability or membrane potential
Activate or inhibit enzymes
Stimulate or inhibit mitosis
Stimulate or inhibit secretion
Turn on/off gene transcription
What two gonadotropin hormones are produced by the anterior pituitary
Follicle Stimulating Hormone (FSH)
Luteinising Hormone (LH)
Name a hormone produced by the thyroid
Thyroxin
Triiodothyronine
Describe the role of the thyroid in calcium homeostasis
Rising Ca2+ triggers the thyroid to release calcitonin, this stimulates calcium to deposit in bone.
Falling Ca2+ detected, parathyroid releases parathyroid hormone (PTH). PTH stimulates osteoclasts to degrade bone, increasing blood Ca2+
What is produced in the adrenal glands?
Aldosterone (by zona glomerulosa)
Corticosteroids (by zona fasciculata)
Adrenaline and noradrenaline (by adrenal medulla)
Androgens
Name two opposing pituitary disorders
Gigantism (hypersecretion of GH)
Dwarfism (hyposecretion of GH)
What is Cushings Syndrome?
Excess free cortisol production
Symptoms of Cushing’s syndrome
Abnormal fat deposits- “buffalo hump”, moon face, female balding, hypertension, hyperglycaemia, etc
What is addisons disease?
Destruction of the zona glomerulosa and zona fasiculata of the adrenal glands causing low output of aldosterone and cortisol
Symptoms of addisons
Hyperpigmentation, hypotension, weakness, nausea, vomiting
Adrenal crisis- fever, syncope, hypoglycaemia, hyponatraemia, hyperkalaemia, severe D&V
Classic symptoms of diabetes
Polyuria, polydipsia, polyphagia
Differences between type and type 2 diabetes
Type 1- autoimmune destruction of pancreatic beta cells
5-10% of cases
Type 2- insulin resistance.
90-95% of cases
Blood glucose ranges?
Healthy/ prediabetic/ diabetic
Healthy: 4 - 5.9mmol/L
Pre: 6 - 6.9mmol/L
Diabetic: > 6.9mmol/L
What disease can cause Addisons?
TB
What gland produces melatonin?
Pineal gland
What gland is located just superiority to the kidneys?
Adrenal Gland
(Ad= above, Renal= kidneys)
Are testosterone receptors within the cell or on the membrane?
Within the cell
What is the largest endocrine gland
Thyroid
What are the catecholamines?
Adrenaline and noradrenaline
Where are the catecholamines produced
Adrenal glands
Is the endocrine system responsible for slow changes or fast responses?
The endocrine system uses hormones secreted into the blood stream so its effect is slow
Where is testosterone produced?
Testes
Explain the mechanism for insulin release
High glucose causes increase ATP production in pancreatic B cells.
ATP gated Na channels open and partially depolarise the cell membrane.
This opens Ca channels, which allow the extravasation of insulin
What’s the main differences between DKA and HHS
DKA- usually affects pt’s with type 1 DM, and is a build up of ketones
HHS- usually affects type 2 DM, osmolality issue due to insulin resistance
Where is progesterone normally produced?
Adrenal glands and gonads
Where is progesterone produced in weeks 0-10 of pregnancy?
Corpus luteum of ovaries
What may cause cushings disease?
Pituitary gland tumour secreting excess Adrenocorticotropic Hormone (ACTH)
Key difference between endocrine and exocrine glands?
Endocrine- secretes hormones directly into the bloodstream
Exocrine- secretes through ducts, like bile duct
Which of these hormones have receptors on the cell membrane:
Progesterone. Testosterone. Oestrogen. Insulin. Cortisol. Thyroxin.
Insulin.
(Insulin can’t go in)
The rest are all lipid soluble so can pass through the membrane.
What is gluconeogenesis?
The production of glucose from non-carbohydrate sources.
(Stimulated by glucagon in response to low BM)
What is glycogenesis and which hormone increase it?
The formation of glycogen from glucose to be stored in muscle cells.
Insulin stimulates this action in response to high BM
What is glycolysis?
The breakdown of glucose for use in ATP production.
Increased by insulin
Which lobular endocrine glands sit superiorly to the hypothalamus?
Anterior and posterior pituitary glands
Name two posterior pituitary hormones
Antidiuretic Hormone (ADH)
Oxytocin
