Semen and Spermatogenesis

Question 1

What is mitosis?

Answer 1

• process of one cell dividing into two identical cells
• each cell contains two sets of chromosomes

Question 2

Process of mitosis

Answer 2

• prophase: chromosomes condense and become visible
• metaphase: chromosomes line up in the middle of the cell
• anaphase: sister chromatids separate and move to opposite ends of the cell
• telophase: cell divides into two identical daughter cells

Question 3

What is meiosis?

Answer 3

• one cell dividing into 4 genetically unique daughter cells
• each cell contains one set of chromosomes

Question 4

Process of meiosis

Answer 4

meiosis I
- prophase I: homologous chromosomes pair up and exchange genetic material
- metaphase I: chromosomes line up in the middle
- anaphase I: chromosomes separate and sister chromatids stay together
- telophase I: two haploid cells are formed

meiosis II
- prophase II: prepares cells for the second division
- metaphase II: chromones line up in the middle
- anaphase II: sister chromatids separate
- telophase II: four haploid cells are formed

Question 5

What is spermatogenesis?

Answer 5

process of sperm production

Question 6

Describe the events of spermatogenesis. What is the relative location of each step?

Answer 6

• spermatogonia (stem cells) divide by mitosis near the periphery of the tubule
• one daughter cell becomes a primary spermatocyte, which moves toward the lumen
• primary spermatocyte undergoes meiosis I and results in two secondary spermatocytes
• each secondary spermatocyte undergoes meiosis II, creating two spermatids
• spermatids transform into spermatozoa (sperm)

Question 7

What type of division happens in each stage of spermatogenesis and what cells result?

Question 8

Order of sperm development: sperm, spermatogonium, spermatid, secondary spermatocyte, primary spermatocyte

Answer 8

• spermatogonium
• primary spermatocyte
• secondary spermatocyte
• spermatid
• sperm

Question 9

What is spermiogenesis? What happens and where does it occur?

Answer 9

• final stage of sperm maturation
• occurs in the seminiferous tubule
• spermatid grows a tail, nucleus condenses, acrosome forms, sheds most of the cytoplasm

Question 10

Function of nurse cells

Answer 10

protect germ cells, provide nutrients, secreting proteins

Question 11

Describe the anatomy of sperm. What is the function of each component?

Question 12

Describe what semen contains and the function of each component

Answer 12

• sperm 2-5%
• seminal vesicle fluid 65-75%
• prostate fluid 25-30%
• bulbourethral gland fluid <1%