Reproductive system
52 flashcards covering Reproductive system for the MCAT Biology & Biochemistry section.
The reproductive system is the body's set of organs and processes that enable the production of offspring. In males, it includes the testes, which produce sperm, and associated ducts and glands for delivery. In females, it features the ovaries, which release eggs, along with the uterus for nurturing a developing fetus. This system also involves hormones like estrogen and testosterone that regulate sexual development, menstrual cycles, and fertility. Understanding it is essential because it highlights how organisms reproduce and adapt, forming a key part of human biology.
On the MCAT, the reproductive system appears in Biology and Biochemistry questions that test anatomy, physiology, and hormonal regulation, often integrated with genetics or evolution. Expect multiple-choice questions on processes like gametogenesis, fertilization, and contraception, as well as common traps like confusing homologous structures or misinterpreting hormone feedback loops. Focus on clinical applications, such as disorders like PCOS or STDs, and how the system interacts with others, like the endocrine system, to avoid errors in passage-based questions.
Memorize key diagrams for quick recall.
Terms (52)
- 01
Testis
The male gonad that produces sperm and testosterone, located in the scrotum to maintain a lower temperature necessary for spermatogenesis.
- 02
Ovary
The female gonad that produces eggs and female sex hormones like estrogen and progesterone, located in the pelvic cavity and containing follicles at various stages of development.
- 03
Epididymis
A coiled tube attached to the testis where sperm mature and gain motility before being stored and transported.
- 04
Vas deferens
A muscular tube that transports mature sperm from the epididymis to the ejaculatory duct during ejaculation.
- 05
Uterus
A muscular organ in females where a fertilized egg implants and develops into a fetus, with its lining thickening and shedding during the menstrual cycle.
- 06
Cervix
The lower, narrow end of the uterus that connects to the vagina and dilates during childbirth to allow passage of the baby.
- 07
Vagina
A muscular canal in females that serves as the birth canal and the site of intercourse, also connecting the cervix to the external environment.
- 08
Fallopian tube
A pair of tubes that transport eggs from the ovaries to the uterus, where fertilization typically occurs in the ampulla section.
- 09
Spermatogenesis
The process of sperm production in the seminiferous tubules of the testes, involving mitosis, meiosis, and differentiation to produce mature spermatozoa.
- 10
Oogenesis
The process of egg production in the ovaries, where primary oocytes undergo meiosis to form a single mature ovum and polar bodies, arrested until puberty.
- 11
Follicle
A structure in the ovary that contains a developing oocyte surrounded by granulosa cells, which produce estrogen and eventually release the egg during ovulation.
- 12
Corpus luteum
A temporary endocrine structure formed from the ruptured follicle after ovulation, secreting progesterone to prepare the uterus for possible implantation.
- 13
Menstrual cycle
A monthly cycle in females involving hormonal changes that lead to the maturation of an egg, preparation of the uterine lining, and menstruation if no pregnancy occurs.
- 14
Follicular phase
The first phase of the menstrual cycle where FSH stimulates follicular development in the ovary, leading to increased estrogen production.
- 15
Luteal phase
The second phase of the menstrual cycle after ovulation, where the corpus luteum produces progesterone to maintain the uterine lining for potential implantation.
- 16
Ovulation
The release of a mature egg from the ovary, triggered by a surge in LH and occurring around the midpoint of the menstrual cycle.
- 17
FSH
Follicle-stimulating hormone, released by the anterior pituitary, that stimulates follicular growth in females and spermatogenesis in males.
- 18
LH
Luteinizing hormone, secreted by the anterior pituitary, that triggers ovulation in females and testosterone production in males.
- 19
Estrogen
A group of female sex hormones produced mainly by the ovaries that regulate the menstrual cycle, promote secondary sexual characteristics, and prepare the uterus for pregnancy.
- 20
Progesterone
A hormone produced by the corpus luteum that maintains the uterine lining for implantation and supports early pregnancy by preventing further ovulation.
- 21
Testosterone
The primary male sex hormone produced by the testes that promotes sperm production, muscle growth, and the development of male secondary sexual characteristics.
- 22
Hypothalamic-pituitary-gonadal axis
A regulatory system where the hypothalamus releases GnRH to stimulate the pituitary gland to secrete FSH and LH, which in turn control gonadal function and hormone production.
- 23
Fertilization
The fusion of a sperm and an egg to form a zygote, typically occurring in the fallopian tube, initiating embryonic development.
- 24
Implantation
The attachment of the blastocyst to the uterine lining about 6-10 days after fertilization, allowing for nutrient exchange and pregnancy establishment.
- 25
Zygote
The initial cell formed by the union of sperm and egg, which undergoes cleavage divisions to become a multicellular embryo.
- 26
Blastocyst
A hollow ball of cells formed from the zygote around 5 days after fertilization, which implants into the uterus and differentiates into the embryo and placenta.
- 27
Gastrulation
The process in early embryonic development where the blastocyst forms a three-layered structure (ectoderm, mesoderm, and endoderm) that gives rise to all body tissues.
- 28
Placenta
A temporary organ that develops during pregnancy, providing oxygen and nutrients to the fetus while removing waste, formed from embryonic and maternal tissues.
- 29
Amniotic sac
A fluid-filled membrane that surrounds and protects the developing fetus, cushioning it from impacts and maintaining a stable environment.
- 30
Seminiferous tubules
Coiled structures within the testes where spermatogenesis occurs, lined with germ cells and supported by Sertoli cells.
- 31
Leydig cells
Cells in the testes that produce testosterone in response to LH, essential for male reproductive function and secondary sex characteristics.
- 32
Sertoli cells
Supportive cells in the seminiferous tubules that nourish developing sperm and form the blood-testis barrier to protect against immune responses.
- 33
Graafian follicle
The mature ovarian follicle that contains a secondary oocyte ready for ovulation, characterized by a fluid-filled antrum.
- 34
Polar bodies
Small cells produced during oogenesis that contain minimal cytoplasm and degenerate, ensuring the egg retains most nutrients for the embryo.
- 35
Acrosome reaction
The process where the sperm's acrosome releases enzymes to penetrate the zona pellucida of the egg, enabling fertilization.
- 36
Capacitation
The activation of sperm in the female reproductive tract, involving changes to the sperm membrane that allow it to fertilize an egg.
- 37
Zona pellucida
A protective glycoprotein layer surrounding the egg that must be penetrated by sperm for fertilization to occur.
- 38
HCG
Human chorionic gonadotropin, a hormone produced by the early embryo that maintains the corpus luteum and prevents menstruation during pregnancy.
- 39
Prolactin
A hormone from the anterior pituitary that stimulates milk production in females after childbirth and can inhibit ovulation during breastfeeding.
- 40
Oxytocin
A hormone released by the posterior pituitary that stimulates uterine contractions during labor and milk ejection during nursing.
- 41
Puberty
The transitional period marked by hormonal changes that lead to the development of secondary sexual characteristics and reproductive maturity.
- 42
Menopause
The permanent cessation of menstrual cycles in females, typically around age 50, due to declining ovarian function and hormone levels.
- 43
Hormonal feedback loops
Regulatory mechanisms where hormones like estrogen and progesterone inhibit or stimulate the release of GnRH, FSH, and LH to maintain balance in the reproductive system.
- 44
Barrier methods of contraception
Physical devices like condoms or diaphragms that prevent sperm from reaching the egg, reducing the risk of pregnancy and sexually transmitted infections.
- 45
Hormonal contraception
Methods like birth control pills that use synthetic hormones to prevent ovulation, thicken cervical mucus, or alter the uterine lining to avoid pregnancy.
- 46
In vitro fertilization
A reproductive technology where eggs are fertilized by sperm outside the body in a lab, and resulting embryos are implanted into the uterus.
- 47
Common trap: Confusing spermatogenesis and oogenesis
Spermatogenesis produces four sperm per spermatogonium through equal cytokinesis, while oogenesis produces one egg and polar bodies through unequal cytokinesis, a key distinction in gamete formation.
- 48
Strategy for remembering hormone functions
Associate FSH and LH with follicular development and ovulation in females, and use acronyms like 'Follicle-Stimulating Helps' to link them to their roles without mixing up with other hormones.
- 49
Example of hormone levels during menstrual cycle
Estrogen peaks just before ovulation, triggering the LH surge, while progesterone rises in the luteal phase to support the uterine lining if fertilization occurs.
- 50
Ectopic pregnancy
A condition where a fertilized egg implants outside the uterus, often in the fallopian tube, which can be life-threatening and requires medical intervention.
- 51
Polycystic ovary syndrome
A common endocrine disorder causing irregular periods, excess androgen production, and cysts on the ovaries, often linked to insulin resistance.
- 52
Vasectomy
A surgical procedure for male sterilization that cuts or blocks the vas deferens to prevent sperm from entering the ejaculate.