Endocrine Disorders - and repo Flashcards
What causes acromegaly (gigantism
Acromegaly is caused by growth hormone hypersecretion, typically due to a GH-secreting pituitary tumor.
What is hyperthyroidism, and what causes it?
Hyperthyroidism is an autoimmune disorder where abnormal antibodies mimic TSH, causing excess thyroid hormone and T3/T4 production.
What is hypothyroidism, and what causes it
: Hypothyroidism is an underactive thyroid due to insufficient thyroid hormone production, caused by a defect in the thyroid gland, TSH, or TRH release.
What is Hashimoto’s thyroiditis?
: Hashimoto’s is chronic autoimmune thyroiditis driven by autoantigen production from TSH Receptor Type A.
What causes hyperparathyroidism, and what are its effects?
Hyperparathyroidism is due to excess PTH, often from a tumor, leading to hypercalcemia, which can impact the nervous system, muscles, and kidneys.
: What causes hypoparathyroidism, and what are its effects?
Hypoparathyroidism results from PTH deficiency, often due to trauma or removal, causing hypocalcemia and neuron hyperactivation.
What is Cushing’s syndrome, and what causes it?
Cushing’s syndrome is caused by excess cortisol due to elevated ACTH from pituitary tumors.
Describe the pathophysiology of Cushing’s syndrome
A pituitary adenoma causes elevated ACTH, increasing cortisol, which disrupts normal cortisol cycles and suppresses CRH due to negative feedback.
What is Addison’s disease, and what causes it
Addison’s disease is due to low corticosteroid levels from either adrenal gland or pituitary gland deficiencies.
What are the roles of FSH and LH in reproductive health?
FSH and LH cause germ maturation and stimulate gonadal production of steroids and inhibins.
How do gonadal steroids and inhibins control FSH and LH levels?
They provide negative feedback to the hypothalamus and pituitary to suppress FSH/LH production.
What role do gonadotrophic hormones play in the ovarian cycle?
They promote maturation and ovulation of ovarian follicles
: Where are inhibins produced, and what is their function
: Inhibin A and B are produced by ovarian follicles and suppress pituitary FSH production.
What is the role of progesterone in pregnancy
Progesterone, produced by the corpus luteum, aids in the establishment and maintenance of pregnancy
Where is oestradiol produced, and what is its function?
Oestradiol is produced by the dominant follicle; it supports follicle maturation and suppresses pituitary FSH production.
What effect does LH have on testicular Leydig cells?
: LH promotes androgen production in Leydig cells
How do FSH and androgens influence spermatogenesis?
They act on Sertoli cells to support spermatogenesis, which is strongly stimulated when both are present.
Describe the mechanism of action in spermatogenesis
LH binds Leydig cells ➔ androgens secreted ➔ FSH binds Sertoli cells ➔ weak spermatogenesis ➔ androgens bind Sertoli cells ➔ FSH increases androgen expression ➔ strong spermatogenesis.
What effect does inhibin loss have on female mice?
Loss of inhibin function leads to increased fat accumulation
How do gonadally derived protein hormones regulate FSH?
They negatively regulate pituitary production of FSH.
: Which types of inhibin do males and females produce?
Females produce both inhibin A and B, while males only produce inhibin B
What can happen if inhibin production is lost
It may cause compensatory activin production, leading to gonadal tumors and cachexia.
: What are common causes of male infertility?
Causes include problems with semen ejection, low or no sperm levels, abnormal sperm shape/movement, and varicoceles.
How does diet affect male infertility?
High-fat diets can decrease testosterone and spermatogenesis, increasing leptin and E2 (conversion of T to E2).
