2. testosteron and semen production

What are the primary endocrine and exocrine functions of the testes?

Endocrine produces hormones; exocrine produces sperm.

Which cells produce testosterone?

Interstitial Leydig cells.

Which hormone stimulates Leydig cells?

Luteinizing hormone (LH) from the anterior pituitary.

What is the precursor of testosterone?

Cholesterol.

What is the function of StAR protein?

Transports cholesterol into mitochondria to begin steroid hormone synthesis.

Where does testosterone synthesis occur?

Begins in mitochondria and continues through enzymes in the smooth ER.

What are the major functions of testosterone?

Maintains male characteristics, accessory sex glands, and supports spermatogenesis.

Which cells secrete Inhibin B?

Sertoli cells.

What is the function of Inhibin B?

Inhibits FSH secretion from the anterior pituitary through negative feedback.

Where does spermatogenesis occur?

Seminiferous tubules.

What is the main function of Sertoli cells?

Nourish and support developing germ cells.

What is the blood-testis barrier?

A barrier that protects developing germ cells from immune attack.

What is the function of androgen-binding protein (ABP)?

Concentrates testosterone in seminiferous tubules for sperm production.

How do endocrine and exocrine secretions leave the testes?

Hormones enter the bloodstream; sperm enter the duct system.

What are the two main components of semen?

Spermatozoa and seminal plasma.

What is spermatogenesis?

The production of sperm cells in the seminiferous tubules.

What happens when sperm leave the seminiferous tubules?

They travel through the ducts toward the epididymis.

What is the primary function of the epididymis?

Sperm maturation and acquisition of progressive motility.

What happens in the epididymal head and body?

Sperm undergo maturation and develop motility.

Where are mature sperm stored?

Tail of the epididymis.

What is the cytoplasmic droplet?

Residual cytoplasm that is normally lost during sperm maturation.

What is seminal plasma?

Fluid from accessory sex glands that supports sperm function.

When is seminal plasma added to sperm?

During emission.

What is the function of the vesicular glands?

Provide seminal fluid containing energy sources such as sugars.

What is the function of the prostate gland?

Adds fluid that supports sperm function and contributes to buffering acidity.

What is the function of the bulbourethral glands?

Produce lubricating mucus.

What is an ejaculate?

The combined sperm and accessory gland fluids expelled during ejaculation.

How does testosterone affect accessory sex glands?

Maintains their development and function.

What is the difference between Leydig and Sertoli cells?

Leydig cells produce testosterone; Sertoli cells support sperm and secrete Inhibin B.

What is the correct sequence from sperm production to storage?

Seminiferous tubules → epididymal head and body → epididymal tail.