IB Biology: Human Reproduction

Scrotom

external sac holding testes to allow for lower body temperature

seminiferous tubules

Narrow, coiled tubules that produce sperm in the testes.

Epididymis

A long, coiled duct on the outside of the testis in which sperm mature.

testis

male reproductive organ that produces sperm and hormones

Leydig cells

Cells in the testis that produce testosterone

Testosterone

Sex hormone, most important in male sperm production

Sertoli cells

cells found within the seminiferous tubules that provide nutrients for spermatogenesis

spermatagonium

germ line cells that can undergo mitosis or meiosis in the testis

Primary spermatocyte

A diploid cell in the testis that undergoes meiosis I.

Secondary spermatocyte

Haploid cells resulting from the first meiotic division of spermatogenesis. These cells will enter meiosis II.

Spermatids

an immature male sex cell formed from a spermatocyte that can develop into a sperm cell without further division.

vas deferens

tube that carries sperm from the epididymis to the urethra

seminal vesicles

two small glands that secrete a fluid rich in sugar that nourishes and helps sperm move

prostate gland

A single gland in males that contributes to the semen

Ovary

produces eggs

Fallopian tube

tubes which carry eggs from the ovaries to the uterus and which provides the place where fertilization occurs

Uterus

Female organ of reproduction used to house the developing fetus.

Cervix

The opening to the uterus

Fertilization

Process in sexual reproduction in which male and female reproductive cells join to form a new cell

Vagina

Entrance to the female reproductive system

Primary oocyte

Diploid cell frozen until puberty in Prophase I of Meiosis

Secondary oocyte

A haploid cell resulting from meiosis I in oogenesis, which will become an ovum after meiosis II.

Graffian follicle

mature follicle that will release the egg at the time of ovulation

corpus luteum

empty ovarian follicle that secretes progesterone after release of the egg cell

Pituitary Gland

Gland in the brain that produces and releases FSH and LH

Hypothalamus

Site in the brain that produces GnRH

Hormone

Chemical messenger that delivers messages to parts of the body by traveling through the bloodstream

FSH (follicle stimulating hormone)

In females, stimulates the ovaries to develop follicles (oogenesis) and secrete estrogen; in males, FSH stimulates spermatogenesis.

LH (luteinizing hormone)

Triggers ovulation

Estrogen

Hormone produced by the follicle that increases the lining of the uterus

Progesterone

hormone produced by the corpus luteum in the ovary and the placenta of pregnant women that maintains the lining of the uterus

Zona Pellucida

Outermost layer of a mammalian egg

cortical reaction

a reaction that occurs during fertilization, when the sperm cell unites with the egg's plasma membrane, that prevents entry of a second sperm.

acrosome

A region at the head of a sperm cell that contains digestive enzymes which, when released during the acrosome reaction, can facilitate penetration of the egg

Placenta

a flattened circular organ in the uterus of pregnant mammals, nourishing and maintaining the fetus through the umbilical cord.

umbilical vein

delivers oxygenated blood from the placenta to the fetus

umbilical arteries

carry deoxygenated blood from the fetus to the placenta

hCG (human chorionic gonadotropin)

Secreted by the embryo and signals the corpus luteum to continue producing progesterone.

Oxytocin

A hormone released by the pituitary that stimulates uterine contractions during childbirth

Prolactin

Hormone that stimulates milk production