Topic 7 - Endocrine system II Flashcards
(26 cards)
Where is the thyroid gland located?
- It’s a bow-shaped (R & L lobe)
- Lies below larynx on either side of trachea
*Controlled by anterior pituitary hormones & secretes T3, T4 & calcitonin
How is the thyroid gland regulated by the anterior pituitary?
- Controlled by TSH (controlled by TRH - thyrotropin-releasing hormone)
- TSH travels by blood -> T4 production stimulation
- Too little T4 = body slowed vs too much T4 = body speed up
*NOTE: Thyroid hormones influence every cell in body (cell diff., growth & metabolism).
What is required for the synthesis of thyroid hormones?
Iodide
What are some actions of thyroid hormones?
INCREASES:
- glucose & aa uptake
- mitochondrial size, no. & activity
- O2 utilisation
- heat production
- basal metabolic rate
- mRNA/protein synthesis
- sympathetic activity
What is hypothroidism?
It occurs when the thyroid gland doesn’t make enough thyroid hormones
What are some different causes of hypothyroidism?
- Auto-immune
- Drug-induced
- Synthetic enzyme deficiency
- Sloppy X-ray technique
- Congenital
- Disease states
What are some symptoms of hypothyroidism?
- Impaired growth
- Lethargy/increased sleep
- Intolerance to cold
- Coarse/dry skin
- decrease perspiration (sweating)
- slow pulse
- constipation/less appetite/increase weight
- Depression/apathy (lack interest/motivation)
- High blood cholesterol
What are the 2 treatments of hypothyroidism?
- T4 = long duration
- Liothyronine (synthetic T3 form) = rapid action/shorter duration - used for severe hypothyroidism
What is hyperthyroidism?
It occurs when the thyroid gland produces to many thyroid hormones
What is the most common cause of hyperthyroidism?
- Auto-immune diseases
- e.g Grave’s disease
What are some symptoms of hyperthyroidism?
- Increased activity/less sleep
- Intolerance of heat
- Rapid pulse
- Accelerated growth
- Frequent bowel movements
- Increase appetite/decrease weight
- Nervous (emotional) state
What are some treatments of hyperthyroidism?
- Thyroid peroxidase inhibitors (block synthesis)
- Surgery (removal of most of thyroid gland)
- Radioactive iodine (destruction of thyroid secretory cells - some)
*NOTE: DIFFERENT SPECIFICS FOR PREGNANCY & LACTATION
Where is the parathyroid glands?
There is 2 on each side of the thyroid (structurally distinct from thyroid gland)
What do parathyroid glands do?
- Produce PTH (parathyroid hormone)
- Have a role in calcium metabolism
Why is calcium important?
- stabilise excitable cell membranes
- release neurotransmitters (involved 2nd messenger function)
- muscle contractility
- exocytosis of hormones & other reg.
- Blood coagulation & platelet aggregation
What is hypoparathyroidism & what causes it?
When parathyroid gland is underactive
CAUSES:
- Throat surgery
- auto immune
- familial
- idiopathic (unknown cause)
What are some symptoms of hypoparathyroidism?
- Muscle spasms
- Convulsions
- Paralysis
- Dyspnoea (feeling X enough air in lungs)
- Gastrointestinal hemmorhage & haematosis
- DEATH
What is hyperparathyroidism and its causes?
When parathyroid gland is overactive - 2 types; primary & secondary
CAUSES:
- Parathyroid adenoma (tumor..)
- Spontaneous hyperplasia (increase in cells)
What are some effects of hyperparathyroidism?
Increased PTH production causing:
- Increased resorption from skeletal system
- Increased absorption of Ca2+ from kidneys/GI systems
What are some symptoms of hyperparathyroidism?
- Renal stones (kidney stones)
- Bone pain
- Pathological fractures
Is the pancreas made up of more exocrine or endocrine tissue?
Exocrine tissue (98%)
*only 2% Endocrine tissue
Where and what do the endocrine & exocrine cells produce?
- Endocrine is in Islets of Langerhans & produce hormones
- Exocrine is in pancreatic acini & produce digestive enzymes
What are the cells that make
up the Islets of Langerhans?
- beta cells (produce/secrete insulin)
- alpha cells (produce/secrete glucagon)
- delta cells (produce/secrete GHIF/somatostatin)
What is Insulin-dependent diabetes/Type 1 diabetes?
Least common diabetes where Beta cells are destroyed by autoimmune disease or viral infection
*Note: treated with insulin injection
