Week 8 Endocrine Flashcards
There are 3 parts to the posterior pituitary gland: the
median eminence, the pituitary stalk and the pars nervosa.
Which part secretes hormones?
Which hormones does it secrete?
The pars nervosa secretes ADH and oxytocin.
What are some factors that might contribute to decreased secretion of antidiuretic hormone (ADH)?
ADH secretion decreases with:
-decreased plasma osmolality
-increased intervascular volume
-HTN
-alcohol ingestion
-increased estrogen, progesterone, or angiotensin II levels
How are intravascular volume changes monitored?
When is ADH secretion stimulated?
Intravascular volume changes from ADH secretion are monitored by baroreceptors in left atrium, carotid arteries, and aortic arch -> ADH secretion is stimulated by a volume loss of 7-25%
Where is ADH secretion regulated?
ADH secretion is regulated by osmoreceptors in hypothalamus, which are stimulated by increased plasma osmolality.
What actions stimulate oxytocin secretion?
- infant suckling; oxytocin binds to receptors in myoepithelial cells in mammary tissues, causing contraction of those cells, leading to milk expression (“let-down”)
- mechanical distensions of female reproductive tract at the end of labour, enhancing the effectiveness of contractions to promote delivery of placenta and post-partum clamp down of the uterus.
True or false:
Oxytocin has an antidiuretic effect similar to ADH.
True.
Where are the parathyroid glands located?
The parathyroid glands are located on the posterior aspect of the thyroid gland.
How many parathyroid glands are there?
There are usually 4 parathyroid glands but there can be between 2 and 6.
Which hormone is produced by the parathyroid glands?
What does this hormone do?
Parathyroid hormone (PTH).
PTH is responsible for regulating serum calcium levels.
When serum calcium is low, PTH is secreted.
What actions are stimulated to increase serum calcium?
PTH causes bone demineralization by stimulating osteoclast activity to release calcium
PTH stimulates the kidneys to reabsorb calcium into circulation
PTH increases absorption of calcium in the intestines
Calcium and ________ have a reciprocal relationship, thus PTH will also act on the kidneys to decrease __________ reabsorption. (same answer)
Phosphate
What are some possible causes for hypoparathyroidism?
Congenital, post-surgery or radiation, or from autoimmune disease.
Hypoparathyroidism leads to?
Hypocalcemia.
Hypoparathyroidism can lead to hypocalcemia.
What are the symptoms/manifestations of hypocalcemia?
Hypocalcemia affects nerve and muscle function causing weakness in cardiac muscle and excitability of nerves leading to muscle twitching and spasms (tetany)
What are some possible causes of hyperparathyroidism?
Adenoma, hyperplasia, secondary to renal failure
Hyperparathyroidism can lead to hypercalcemia.
What are the symptoms/manifestations of hypercalcemia?
Hypercalcemia causes forceful cardiac contractions, kidney stone risk, and osteoporosis as the high levels of PTH result in removal of calcium from the bone
The adrenal medulla, the inner part of an adrenal gland, controls hormones that initiate the…?
…the flight or fight response (Sympathetic Nervous System)
The adrenal medulla secretes _________, hormones that help your body respond to stress
Catecholamines
Catecholamines include adrenaline and noradrenaline, also known as…
Epinephrine and norepinephrine
Blood glucose concentration is determined by a balance between insulin and glucagon secretion by which organ?
Pancreas.
Increased blood glucose (e.g. after eating a meal) will trigger _______ in the pancreas to secret insulin.
B cells
Insulin will lower blood sugar levels by triggering tissue cells (such as fat or muscle cells) to take up glucose for energy and also by stimulating glycogen formation in the _____ (where glucose is stored as glycogen).
Liver
Reduction of blood glucose causes a reduction in _______ secretion and brings the system back to homeostasis.
Insulin
Low blood glucose levels trigger the release of glucagon from ________of the pancreas.
A cells
Which hormone is secreted with insulin and inhibits glucagon secretion?
Amylin plays a role in glycemic regulation by slowing gastric emptying and promoting satiety, thereby preventing post-prandial spikes in blood glucose levels.
Which hormone inhibits secretion of insulin and glucagon after glucose is broken down or transferred to cell?
Somatostatin.
Define metabolic syndrome.
A group of disorders (central obesity, dyslipidemia, prehypertension, and an elevated blood glucose level) that together give a high risk of development type 2 diabetes and associated cardiovascular complications.
Which two presentations are considered the strongest predictors for the development of metabolic syndrome.
Elevated triglycerides and waist circumference.
_________ is considered a proinflammatory and prothrombotic state.
Metabolic syndrome.
What are some complications associated with metabolic syndrome?
-Fatty liver disease
-Cirrhosis
-Chronic kidney disease
-CV disease
-Polycystic ovarian syndrome (PCOS)
-Obstructive sleep apnea (OSA)
-Gout
What are some risk factors for developing metabolic syndrome?
*Genetic predisposition.
*Weight gain, especially central/abdominal obesity.
*Females (postmenopausal)
*Childhood obesity.
*Smoking.
*High-carbohydrate diet, especially soft drink consumption.
*Lack of exercise
*Sedentary lifestyle.
*Insulin resistance.
What is the treatment plan for a patient who has been diagnosed with metabolic syndrome?
*Identify and treat pt with hyperglycemia
*Management of hypertension, dyslipidemia and abdominal obesity
*Diet modification, exercise (minimum 30min/day), weight loss, smoking cessation
A term referring to impaired fasting glucose (IFG), impaired glucose tolerance (IGT) or an elevated A1C%, each of which places individuals at high risk of developing diabetes.
Prediabetes.
The combination of FPG of 6.1 - 6.9 mmol/L and an A1C of 6.0% - 6.4% is predictive of 50% progression to type 2 diabetes over a 5-year period.
True or false?
False. It is 100% predictive.
Subclinical hypothyroidism is defined biochemically as_______ T4 in the presence of an elevated TSH.
(decreased / normal / elevated?)
Normal
An autoimmune disorder where autoreactive T cells and circulating autoantibodies target and infiltrate the thyroid, resulting in gradual inflammatory destruction
Hashimoto’s Thyroiditis.
Differentiate between primary hypothyroidism and secondary hypothyroidism.
Primary: Caused by disease in the thyroid
Secondary: Caused by disease in the pituitary or hypothalamus.
True or false?
Subclinical hypothyroidism may be associated with an increased risk of cardiovascular disease.
True.
Hypothyroidism affects all body systems and symptoms can vary in relation to the magnitude of TH deficiency. Generally, hypothyroidism leads to a slowing of metabolic processes and myxedema.
What signs and symptoms could you see in terms of metabolism and neuro?
Metabolism: Low metabolic rate, weight gain, cold intolerance, and slightly lowered basal body temperature.
Neuro: Lethargy, fatigue, memory or mental impairment, difficulty concentrating, and slowed speech or thinking.
Hypothyroidism affects all body systems and symptoms can vary in relation to the magnitude of TH deficiency. Generally, hypothyroidism leads to a slowing of metabolic processes and myxedema.
What signs and symptoms could you see in terms of the physical thyroid itself and CVS?
Thyroid: normal, small, or increased (Goitre).
Cardio: Bradycardia, hypertension, pericardial effusion.
Hypothyroidism affects all body systems and symptoms can vary in relation to the magnitude of TH deficiency. Generally, hypothyroidism leads to a slowing of metabolic processes and myxedema.
What signs and symptoms could you see in terms of respiratory and GI/Reproductive systems?
Resp: SOB, Pleural effusion.
GI/Repro: Constipation, heavy or irregular menstrual periods.
Hypothyroidism affects all body systems and symptoms can vary in relation to the magnitude of TH deficiency. Generally, hypothyroidism leads to a slowing of metabolic processes and myxedema.
What signs and symptoms could you see in terms of skin and GI/Reproductive systems?
Skin: Dry and flaky skin. Course and brittle hair with possible loss.
MSK: Delayed deep tendon reflexes, muscle aches, and paresthesia to hands and feet.
What are some presentations of myxedema?
Myxedema: Characteristic sign of severe or longstanding hypothyroidism. Usually seen in the eyes, hands, feet, and supraclavicular fossa. The tongue and laryngeal and pharyngeal mucous membranes can also thicken, producing thick, slurred speech and hoarseness.
Myxedema coma: Severe hypothyroidism. Mortality 30-50%. Usually occurs in undiagnosed or untreated hypothyroid patients, and can be precipitated by an acute event.
Pretibial myxedema is a presentation unique to which disease?
Graves disease.
↑TSH and normal fT4
Subclinical hypothyroidism or primary hypothyroidism?
Subclinical hypothyroidism.
In primary hypotension you will also see decreased fT4.
Which lab test may help determine if Hashimoto’s thyroiditis is the cause of hypothyroidism?
Anti-TPO (antithyroid antibody).