Spermatogenesis and Sperm Development

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Questions and Answers

What is the average number of sperms ejaculated by a human male during coitus?

500 to 600 million

100 to 200 million

200 to 300 million (correct)

400 to 500 million

What percentage of sperms must have normal shape and size for normal fertility?

50%

70%

40%

60% (correct)

What percentage of sperms must show vigorous motility for normal fertility?

30%

40% (correct)

50%

60%

What is the composition of semen?

Sperm (10%) + seminal plasma Signup and view all the answers

What is the process of formation of ovum from oogonia called?

Oogenesis Signup and view all the answers

How many oogonia are formed during the embryonic stage?

2 millions Signup and view all the answers

What is the stage at which all oogonia undergo first meiotic division and get temporarily arrested?

Prophase-I Signup and view all the answers

What is the term for the first menstruation that begins at puberty?

Menarche Signup and view all the answers

How many sperms are produced from each spermatocyte?

4 sperms Signup and view all the answers

What is the role of the zona pellucida layer during fertilization?

To block sperm entry after one sperm enters Signup and view all the answers

How many polar bodies are produced from each oocyte during maturation?

3 polar bodies Signup and view all the answers

Which hormone is secreted by the ovary later in pregnancy that helps in relaxing the pelvic ligaments?

Relaxin Signup and view all the answers

What contribution do acrosomal secretions make during fertilization?

They help sperm penetrate the zona pellucida Signup and view all the answers

What are the additional hormones increased in maternal blood during pregnancy besides hCG and hPL?

Cortisol and prolactin Signup and view all the answers

What is the primary outcome of fertilization?

Formation of a zygote from sperm and ovum Signup and view all the answers

Which of the following statements about oocyte development is true?

Each oocyte produces one ovum and three polar bodies Signup and view all the answers

What is the process called that transforms spermatids into spermatozoa?

Spermiogenesis Signup and view all the answers

Which structure within the sperm is responsible for energy production?

Middle piece Signup and view all the answers

What is the term for the release of sperm from the seminiferous tubules?

Spermiation Signup and view all the answers

Which part of the sperm contains lytic enzymes to assist in penetrating the ovum?

Acrosome Signup and view all the answers

During which process do the mammary glands start producing milk?

Lactation Signup and view all the answers

Which part of the female anatomy stores the milk before it is ejected?

Mammary ampulla Signup and view all the answers

What is the shape of the sperm head?

Oval Signup and view all the answers

Which type of tissue is found in mammary glands?

Glandular and fatty tissue Signup and view all the answers

Study Notes

Spermatogenesis and Sperm Structure

Spermatids transform into spermatozoa through spermiogenesis.
Sperm heads embed in Sertoli cells before being released from seminiferous tubules via spermiation.
Structure of sperm includes:
- Head: Oval shaped with a nucleus and an acrosome containing lytic enzymes for penetrating the ovum.
- Middle Piece: Contains mitochondria providing energy for sperm motility.
- Tail: Facilitates movement in a fluid medium.
Approximately 200 to 300 million sperm are ejaculated during coitus; fertility requires:
- 60% of sperm with normal shape and size.
- 40% demonstrating vigorous motility.
Sperm combined with seminal plasma forms semen.

Mammary Glands

Female mammary glands are paired structures composed of glandular and fatty tissue.
Differentiation occurs during pregnancy; milk production begins towards the end of pregnancy through lactation, aiding in newborn nutrition.
Mammary gland structure includes:
- 15-20 lobes divided into clusters of alveoli, which secrete milk into cavities (lumens).
- Milk ejection pathway: alveoli → mammary tubules → mammary duct → mammary ampulla → lactiferous duct → nipple.

Fertilization Process

Fertilization involves the fusion of sperm and ovum, creating a zygote, dependent on simultaneous transport to the ampullary region.
A sperm contacts the zona pellucida of the ovum, leading to membrane changes to block additional sperm entry.
Each primary spermatocyte produces four sperm, while each oocyte results in one ovum and three polar bodies.

Hormonal Control During Pregnancy

Hormones like hCG, hPL, relaxin, estrogens, progestogens, cortisol, prolactin, and thyroxine increase significantly during pregnancy.
Relaxin assists in preparing the body for childbirth.

Menstrual Cycle and Oogenesis

Oogenesis is the formation of ovum from oogonia, occurring in fetal ovaries.
Menstrual cycles reflect cyclical ovarian activity and hormonal changes, averaging 28-29 days.
Menstruation starts at puberty (menarche) and ceases around age 50 (menopause).
Oogonia (46 chromosomes, 2n) form approximately 2 million primary oocytes that are arrested at prophase I of the first meiotic division.

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Description

This quiz covers the process of spermiogenesis, where spermatids transform into spermatozoa, and spermiation, where sperm heads are released from seminiferous tubules.