Male Reproductive System and Gametogenesis Overview

Zygote

Cell formed by fusion of male and female gametes.

Sperm

Male gamete with motility for fertilization.

Y Chromosome

Chromosome determining male sex in mammals.

Egg (Ovum)

Female gamete providing nutrients for embryo.

Female Parent

Produces eggs and provides prenatal nutrition.

Male Parent

Produces sperm and carries Y chromosome.

Chromosomal Sex Determination

Sex determined by XX or XY chromosome pairs.

Autosomes

22 pairs of non-sex chromosomes in humans.

Sex Chromosomes

1 pair determining biological sex (XX or XY).

Cytokinesis

Division of cytoplasm after mitosis or meiosis.

Interphase

Phase before cell division; cell prepares for mitosis.

Diploid Cell

Cell with two complete sets of chromosomes.

S Phase

Phase where DNA is replicated in interphase.

Prophase

Chromosomes condense and become visible.

Metaphase

Chromosomes align at the cell's equatorial plane.

Anaphase

Homologous chromosomes or sister chromatids separate.

Telophase

Nuclear envelopes reform around separated chromosomes.

Cleavage Furrow

Indentation in the cell surface during cytokinesis.

Meiosis

Two rounds of cell division producing four haploid cells.

Haploid Cell

A cell with ONE set of chromosomes, which is half of the regular (diploid) number.

Meiosis I

First division; homologous chromosomes separate.

Meiosis II

Second division; sister chromatids separate.

Prophase I

Homologous chromosomes pair and exchange DNA segments.

Tetrad

Structure formed by homologous chromosomes during prophase I.

Crossover

Exchange of genetic material between nonsister chromatids.

Chiasmata

X-shaped regions where crossing over occurs.

Metaphase I

Tetrads align at the metaphase plate.

Anaphase I

Homologous chromosomes move toward opposite poles.

Telophase I

Nuclear envelopes form; cytokinesis produces two haploid cells.

Prophase II

Spindle apparatus forms; similar to mitosis.

Telophase II

Nuclear envelopes reform; cytokinesis produces four distinct cells.

Gametes

Haploid cells formed from meiosis, used in reproduction.

Spermatogenesis

Process of sperm cell development involving mitosis and meiosis.

Spermiogenesis

Process of sperm maturation in seminiferous tubules.

Spermiation

Release of spermatozoa into seminiferous tubule lumen.

Spermatozoan

Mature male gamete involved in reproduction.

Acrosome

Cap on sperm head containing enzymes for fertilization.

Middle piece of sperm

Contains mitochondria for ATP production.

Tail of sperm

Enables motility with corkscrew motion.

Gubernaculum testis

Connective tissue guiding testis descent.

Scrotum

Pouch containing testes, regulates temperature.

Cremaster muscle

Adjusts testis position for temperature control.

Dartos fascia

Contracts to wrinkle scrotum, reducing heat loss.

Pampiniform plexus

Venous network cooling arterial blood to testes.

Tunica albuginea

Fibrous capsule surrounding each testis.

Seminiferous tubules

Site of sperm production within testis lobules.

Blood-testis barrier

Prevents immune attack on developing sperm.

Efferent ductules

Transport sperm from rete testis to epididymis.

ductus deferens (vas deferens)

Tube connecting epididymis to seminal vesicle.

Ejaculatory duct

Formed by merging ductus deferens and seminal vesicle.

Seminal vesicles

Glands producing 60% of semen volume.

Prostate gland

Produces 30% of semen, surrounds urethra.

Bulbourethral glands

Secrete pre-ejaculate for lubrication.

Corpus spongiosum

Erectile tissue surrounding the penile urethra.

Corpora cavernosa

Two erectile tissues facilitating penile erection.

Puberty

Onset of reproductive system activity around age 12.

Androgens

Hormones responsible for male secondary sexual characteristics.

Hypothalamo-pituitary-gonadal axis (HPG axis)

Regulatory system controlling male reproductive hormones.

Testosterone

Primary male sex hormone, influences libido and spermatogenesis.

Erectile dysfunction

Inability to achieve or maintain an erection.

Semen

Fluid containing sperm expelled during ejaculation.

Semen composition

Includes seminal plasma from various glands.

Orgasm

Climax marked by ejaculation and intense pleasure.

Refractory period

Time post-orgasm where another erection is impossible.

Epididymitis

Inflammation of the epididymis, often painful.

Testicular torsion

Twisting of spermatic cord, risking testicular necrosis.

Prostate cancer

Common cancer affecting older men, screening recommended.

Mitochondria

Organelles in sperm middle piece providing ATP.

Corkscrew motion

Tail movement of sperm facilitating propulsion.

Temperature control

Mechanisms maintaining testes at 35°C for sperm production.

Tunica vaginalis

Serous membrane covering the testes.

Blood-testis barrier (BTB)

Protective barrier preventing immune attack on germ cells.

Testicular cancer

Cancer primarily affecting young men, often one testicle.

Phosphodiesterase inhibitors

Medications enhancing erectile function by increasing cGMP.

Inguinal hernia

Protrusion of tissue through abdominal wall into inguinal canal.

Peyronie's disease

Scar tissue causing painful, curved erections.