Laronda Lab Vocabulary
Atresia The naturally-occurring degeneration of follicles after they have formed (but before they
have fully matured) through hormonally regulated apoptosis.1
Control-rate (slow) freezing A slow freezing method that allows for control of the nucleation site to prevent ice
formation within cells and tissues.
Corticomedullary junction A location that marks the transition between the ovarian cortex and medulla.
Cryopreservation A process where cells or whole tissues are processed in protective media and stored in
low sub-zero temperatures. Cryopreservation allows for minimal biological activation and
preservation of cellular function.
Cryoprotectant A substance that prevents the formation of ice crystals in frozen cells.
Egg (ovum) The female reproductive cell or gamete.
Folliculogenesis The process of ovarian follicle development that is often broken down into discrete
follicle stages. The fully-grown oocyte is released from the follicle in response to
hormonal cues at the time of ovulation.1
Functional tissue unit (FTU) Structure or group of cells performing a unique physiologic function and replicated
multiple times in a whole organ.2
Gamete Reproductive cell of an animal or plant.3
Germ cells General term that can refer to primordial germ cells (PGCs), oocytes, or spermatids.
Granulosa cell Steroidogenic somatic cell that surrounds the oocyte, providing it with the physical
support and nutrients needed for proper oocyte development.1
Gonadal sex determination Process in which an undifferentiated gonad forms ovaries or testes; in humans, it
initiates around 6 weeks gestation.1
Gonads Primary reproductive organs responsible for producing the sperm and ova and secreting
hormones.4
Leydig cells Testosterone-producing cells in the testes located outside of the seminiferous tubule.5
Oocyte A female germ cell that is not yet ready for fertilization. The oocyte matures into an ovum
(egg) that will be released during ovulation.1
Ovarian cortex The outer layer of the ovary defined by the presence of primordial follicles known as
the ovarian reserve.
Ovarian follicle The functional unit of the ovary, composed of an oocyte surrounded by companion
(somatic) cells, including granulosa cells and theca cells.
Ovarian hilum A transitional region in which blood vessels, nerves, and lymphatic vessels enter or exit
the ovary.
Ovarian medulla The inner layer of the ovary composed of loose connective tissue, blood vessels, nerves,
and late-stage follicles.
Ovarian reserve The fixed number of primordial follicles that dictates a female’s reproductive lifespan. In
humans, ovarian reserve is established prior to birth.
Ovarian tissue
cryopreservation (OTC)
Technique developed to preserve oocytes within tissue for future use.
Ovary One of a pair of female glands in which the eggs form and the female hormones
estrogen and progesterone are made.
Primordial follicle The quiescent stage of ovarian follicular development. The primordial follicle consists of
an oocyte surrounded by a single layer of flat (squamous) granulosa cells.1
Primordial germ cells (PGCs) The earliest recognized gamete precursors. During embryonic development, these cells
arise from the epiblast and migrate to the gonads, which they then populate. Eventually,
through the process of maturation, these cells become functional gametes.
6
Seminiferous tubules Compartment in which spermatogenesis occurs; house the entirety of the germ cell
population as well as the Sertoli cells.5
Sex determination The process in which the undifferentiated gonad develops into an ovary or testis, largely
driven by the presence or absence of the Y chromosome and SRY gene.7
Sertoli cells Somatic cells (non-germ cells) within the seminiferous tubules of the testis that support
the germ cells as they develop, providing them with nutrients and growth factors.5
Spermatogenesis Process by which male gametes (spermatozoa or sperm) are produced.
Sperm cryopreservation The standard of care approach for preserving fertility in adult and adolescent male
patients; involves cryopreserving a sample of an ejaculate containing mature sperm.
1
Steroid hormones Naturally occurring hormones produced in the adrenal glands, testes, and ovaries that
have a variety of functions, including development of secondary sex characteristics,
regulation of the menstrual cycle and pregnancy, and other vital biological roles.
Testis The primary tissue of the male reproductive system located inferior to the penis inside
the scrotum. It is the site of spermatogenesis and is also involved in the synthesis and
secretion of masculinization hormones.5
Testicular tissue
cryopreservation (TTC)
Only option to preserve fertility in prepubertal patients with testes who are not yet able to
produce sperm; TTC requires surgical removal of a piece of testicular tissue which is
then processed and cryopreserved for future use.8
Theca cell Somatic cells of the developing follicle that form an enveloping sheath around the
granulosa cell layer(s). Theca cells produce androgens, and the theca cell layer also
provides structural and vascular support for the growing follicle until ovulation.