Spermatogenesis

Question 1

Spermatogenesis

Answer 1

Process that includes the formation and development/maturation of spermatozoa

It is a continual process that continues throughout a mans life and starts at puberty, It takes about 72 days to produce mature spermatozoa.

A man will make around 200 million a day.

Question 2

Seminiferous tubules

Answer 2

• Found in the testes.
• They have a basement membrane on which the epithelial cells sit, these cells are known as sertoli cells and spermatogonia

The sertoli cells form a microenvironment for the developing sperm cells by enveloping them in their cell membrane.

During development, the spermatogonia move from the basement membrane to the lumen of the tubule, until they reach maturity and are released into the lumen

Question 3

3 Spermatogenesis stages

Answer 3

1. mitotic stage - spermatogonia undergo mitosis.
2. Meiotic stage - spermatocytes undergo meiosis
3. Spermiogenesis - spermatids mature into spermatozoa

Question 4

Spermatogonia

Answer 4

A spermatogonia is a stem cell that can differentiate in order to eventually form sperm. They are found in seminiferous tubules.

Question 5

2 types of spermatogonia

Answer 5

Type A: stem cells are found against the basement membrane of the seminiferous tubule and under go mitosis in order to produce 2 cells, one will stay as type A and the other will start to differentiate.

Type B: These cells are pushed away from the basement membrane, they will usually undergo another 1-3 mitotic divisions before differentiating into primary - spermatocytes.

Question 6

Spermatozoa

Answer 6

Mature male gametes; Sperm

Question 7

Spermiogenesis

Answer 7

Final stage of sperm production, structure and shape changes in order to fertilise an egg.

Question 8

Spermatocytes

Answer 8

specialised cells found in the testes during the process of making sperm (spermatogensis)

Question 9

Spermatids

Answer 9

The haploid male gametid that results from the division of secondary spermatocyte.

Question 10

Spermiation

Answer 10

Process where mature spermatids are released from sertoli cells into the seminiferous tubule lumen.

Marking the final stage of spermatogenesis.

Question 11

Gametogenesis

Answer 11

Gamete development, from meiosis to mature gametes.

Question 12

Structure of sperm

Answer 12

• Head
• Neck
• Middle phase
• Tail

Question 13

Head region

Answer 13

• Consists almost entirely of the nuclear material, with a fluid filled vesicle at its tip, called the acrosome.

In the fluid are enzymes, which are important if the sperm reaches the egg.

The enzymes break down the later of cells surrounding the egg so that fertilisation can occur.

Question 14

Neck

Answer 14

Lies between the head and the middle piece

Question 15

Middle piece

Answer 15

Contains mitochondria where respiration takes place to provide the sperm with energy for movement.

Around the mitochondria there is a thin later of cytoplasm.

As there is little cytoplasm, sperm has a short survival time and receive their nutrients from semen.

Question 16

Tail

Answer 16

Is capable of contractile motions to propel the cell forward.