Spermatogenesis and Oogenesis Practice Flashcards

Vocabulary flashcards covering the biological processes of spermatogenesis and oogenesis, including key structures, cell types, and meiotic variation.

Spermatogenesis

The development and maturation of spermatozoa for fertilisation in sexual reproduction, occurring only in males and continuing throughout life.

Spermatogonia

Diploid parent sperm cells that line the seminiferous tubules (inside testis) and undergo mitosis to provide a continuous source of cells.

Seminiferous tubules

Structures inside the testis lined with spermatogonia where the initial stages of spermatogenesis occur.

Epididymis

The structure that stores and matures spermatozoa.

Primary spermatocyte

A diploid cell formed when a daughter cell from spermatogonia mitosis is pushed inward and enlarges; these begin mitotic division at puberty.

Secondary spermatocytes

Two haploid cells produced when primary spermatocytes undergo the first stage of meiosis.

Spermatids

Four haploid cells formed when secondary spermatocytes undergo the second stage of meiosis.

Spermatozoa

Mature male gametes formed from spermatids that have lost most of their cytoplasm and developed a contractile tail; the process takes $72$ days.

Acrosome

A structure located at the head of the sperm containing enzymes to digest the zona pellucida surrounding the ova.

Middle piece (Spermatozoa)

The section of the sperm containing mitochondria to supply energy for movement and a small amount of cytoplasm.

Zona pellucida

The layer of cells surrounding the ova that the sperm's acrosome must penetrate to cause fertilisation.

Crossing Over

A method of variation during Prophase I where homologous chromosomes pair up, tangle, and form a chiasma, causing chromatids to break and form new recombinant chromatids.

Random Assortment

A method of variation occurring during Metaphase I where homologous chromosomes line up in random formations, creating a large number of chromosome combinations.

Non-Disjunction

An error during Anaphase I or II where one or more chromosomes fail to separate, resulting in aneuploidy.

Aneuploidy

An anomalous number of chromosomes resulting from non-disjunction.

Oogenesis

The process in the ovary that produces a single functional ovum from each primary oocyte.

Oogonia

Diploid mother (parent) cells in females that develop before birth and undergo mitosis to produce several hundred thousand cells.

Primary oocyte

A diploid cell formed from oogonia that begins Meiosis I before birth but is arrested at Prophase I until puberty.

Primary follicle

A structure consisting of a primary oocyte surrounded by a layer of granulosa cells for nourishment.

Secondary oocyte

A haploid cell containing $23$ chromosomes and most of the cytoplasm, formed when a primary oocyte completes the first meiotic division.

Polar body

A small haploid cell with minimal cytoplasm produced during the meiotic divisions of oogenesis that eventually disintegrates.

Metaphase II (Oogenesis)

The stage at which the secondary oocyte is arrested during ovulation until it is penetrated by a spermatozoa.

Ootid

The cell produced if a secondary oocyte is fertilised and completes Meiosis II, which then matures into the ovum.

Menopause

The stage in a woman's life, usually between the ages of $45$ to $60$ years old, when ovulation ceases due to a reduction in mature ova.