Endocrine Flashcards
What are the dual functions of testes and ovaries?
Both produce gametes (sperm in males, oocytes in females) and secrete reproductive hormones.
What is the role of reproductive hormones?
Essential for the development of sexual characteristics and regulation of reproductive functions.
What hormone is secreted by the testes?
Testosterone
What are the functions of testosterone?
- Regulates sperm production
- Develops and maintains male reproductive organs
- Influences secondary sexual characteristics like facial hair, deep voice, and muscle growth
What hormones are secreted by the ovaries?
Estrogen and progesterone
What are the functions of estrogen and progesterone?
- Control the female reproductive cycle with the help of FSH and LH
- Prepare the mammary glands for lactation
- Support and maintain pregnancy
- Develop and maintain female reproductive organs and secondary sexual characteristics
What is the role of LH (Luteinizing Hormone) and FSH (Follicle-stimulating Hormone) in males and females?
Stimulate hormone secretion in the testes and ovaries
How are LH and FSH regulated?
Controlled by a releasing hormone from the hypothalamus and regulated through a negative-feedback mechanism.
Where is the thymus gland located?
A bilobed lymphoid organ in the upper chest, behind the breastbone and between the lungs.
What is the primary function of the thymus gland?
Produces hormones like thymosin needed for the development and maturation of T-lymphocytes (T-cells).
What happens to the thymus gland after puberty?
It gradually decreases in size, a process known as involution.
What is the first stage of thymocyte maturation?
Subcapsular Region
What are the key markers in the DN1 stage?
High CD44, No CD25
What occurs during the DN3 stage of thymocyte maturation?
Completion of TCR beta chain rearrangement; expression of pre-TCR complex.
What is positive selection in T-cell development?
T cells interact with thymic epithelial cells to learn MHC restriction.
What is negative selection in T-cell development?
Elimination of T cells with high-affinity interactions with self-peptides to prevent autoimmunity.
What hormones are present in the subcapsular region and cortex of the thymus?
- Thymosin
- Thymosin Alpha 1
- Thymulin
- Thymic Humoral Factor (THF)
What condition is characterized by thymic hyperplasia?
Swollen and inflamed thymus, often occurring in autoimmune disorders.
What is myasthenia gravis (MG)?
A condition where muscles weaken and tire, often associated with impaired thymus function.
What is DiGeorge syndrome?
A condition causing T-cell deficiency due to an absent or underdeveloped thymus gland at birth.
What are the two types of thyroid hormones?
- Thyroxine (T4)
- Triiodothyronine (T3)
What is the main form of thyroid hormone produced by the thyroid gland?
Thyroxine (T4)
What condition results from an underactive thyroid?
Hypothyroidism
