6 - Endocrine Glands Flashcards
What are the main endocrine glands, where are they located and what do they release?
- Thyroid also releases calcitonin to lower blood Ca
- Adrenal also releases aldosterone, increases sodium reabsorption
What other organs have endocrine function, what do they secrete and what do these secretions do?
What are the diffferent types of hormones?
What is the role of the hypothalamus?
- Thermoregulation
- Osmolality
- Heart rate, blood pressure
- Circadian rhythms
- Emotion, mood
- Lactation
Produces ADH and oxytocin (nervous)
Six hormones (blood)
What is a portal system and where are they found?
- Hypothalamo-hypophyseal portal system
- Hepatic
Why is there always a small amount of hormone in the blood?
Constitutive merocrine secretion
What is the anatomical structure of the thyroid gland?
What is the histiological structure of the thyroid gland?
What is the function of the thyroid and how is it stimulated?
- Combine iodine and tyrosine to make T3 and T4
- Negative feedback of T3 and T4
What is goitre?
Enlargement of the thyroid gland, can be due to iodine deficiency or hyper/hypothyroidism
What is hypothyroidism?
- Hashimoto’s
- High TSH but low T3 and T4
- Due to antibodies, anti TG (thyroglobulin) and anti-TPO (attack thyroid cells)
What is hyperthyroidism?
- Grave’s disease
- High T3/T4, low TSH
- Due to antibodies, anti-TSH and TSI (thyroglobulin stimulater)
What is the anatomy and function of the parathyroid?
- 4 glands on posterior of thyroid gland
- Lots of adipose, chief cells and oxyphil cells
- Release PTH when blood Ca is low, raises blood Ca levels
What is a chief cell and an oxyphil cell?
- Chief: cells in parathyroid that produce PTH
- Oxyphil: no known function but appear at puberty
What is the structure of the adrenal glands?
LEFT = half moon
RIGHT = pyramid
What are chromaffin cells?
- Epithelial cells classed as post-ganglionic sympathetic neurones
- Produce and secrete nor/adrenaline
What are produced at each level of the adrenal cortex?
What is the function of the following?
- Aldosterone (mineralcorticoid)
- Cortisol (glucocorticoid)
- Androgen
- Increase b.p by salt and water balance
- Stress hormone when low blood glucose (not during starvation)
- Precursor for sex hormone
What is the stress response?
Stress is the state of percieved or real threat to homeostasis leading to behaviour and physiological adaptations
How does the body respond to stress short term and long term?
- ACTH from hypothalamo-hypophysesal portal system
- ACTH binds to receptors on adrenal gland
What is the anatomical positon of the pancreas?
- Lies behind stomach with head lying in curve of duodenum on right
- Pancreatic duct –> bile duct –> common bile duct
- Acinar glands
What are some secretions from the exo and endocrine part of the pancreas?
