Human Reproduction Flashcards

Comprehensive vocabulary flashcards covering human reproduction, hormonal control cycles, fertilisation, pregnancy, birth, and reproductive health based on the lecture notes.

Menstrual cycle

A series of cyclical changes in the female reproductive system controlled by the endocrine system, lasting an average of 28 days (ranging 21–35 days).

FSH (Follicle-Stimulating Hormone)

A hormone secreted by the anterior pituitary gland (hypophysis) that stimulates primary follicles in the ovary to develop into mature Graafian follicles.

Graafian follicles

Mature follicles in the ovary that develop from primary follicles under the influence of FSH and secrete oestrogen.

Ovarian Cycle

The sequence of changes in the ovary consisting of the follicular phase (days 1–14), ovulation (day ~14), and the luteal phase (days 15–28).

Ovulation

The release of a secondary oocyte (immature ovum) from the ovary into the fallopian tube, triggered by an LH surge on approximately day 14.

Luteal Phase

The third phase of the ovarian cycle (days 15–28) where the corpus luteum forms and secretes progesterone.

Corpus luteum

A 'yellow body' formed from the remains of the ruptured Graafian follicle that secretes progesterone and small amounts of oestrogen.

LH (Luteinising Hormone)

A hormone from the pituitary gland that triggers ovulation and stimulates the formation of the corpus luteum to secrete progesterone.

Progesterone

A hormone produced by the corpus luteum or placenta that maintains and thickens the endometrium and inhibits FSH and LH secretion.

Uterine Cycle

The series of changes in the endometrium consisting of menstruation (days 1–5), repair/thickening (days 6–14), and preparation for implantation (days 15–28).

Menstruation

The phase (days 1–5) where the endometrium breaks down and is shed as menstrual flow after progesterone levels drop.

Proliferative Phase

The uterine cycle phase (days 6–14) where rising oestrogen stimulates the repair and thickening of the endometrium.

Secretory Phase

The uterine cycle phase (days 15–28) where progesterone causes the endometrium to become glandular and highly vascular, suitable for implantation.

HCG (Human Chorionic Gonadotropin)

A hormone secreted by the blastocyst or placenta that maintains the corpus luteum during pregnancy.

Menopause

The period usually occurring between ages 46–54 when ovaries stop producing hormones and releasing eggs, leading to the cessation of menstruation.

Fertilisation

The fusion of the sperm nucleus $(n)$ with the egg nucleus $(n)$ in the fallopian tube to form a diploid zygote $(2n)$, following the acrosome reaction.

Acrosome reaction

The process where hydrolytic (lytic) enzymes from the sperm's acrosome dissolve the zona pellucida of the secondary oocyte.

Zygote

The diploid $(2n)$ cell resulting from the fusion of a sperm and egg nucleus.

Morula

A solid ball of cells, resembling a mulberry, formed by rapid mitotic divisions (cleavage) of the zygote.

Blastocyst

A hollow, fluid-filled sphere consisting of an outer trophoblast and an Inner Cell Mass (ICM).

Trophoblast

The outer layer of cells in the blastocyst that forms the placenta and chorion and secretes enzymes to embed into the endometrium.

Implantation

The process occurring approximately 10 days after fertilisation where the blastocyst sinks into the thickened, vascular endometrium.

Ectoderm

The outer embryonic layer that forms the nervous system and skin.

Mesoderm

The middle embryonic layer that forms the muscles, skeleton, and circulatory system.

Endoderm

The inner embryonic layer that forms the digestive and respiratory systems.

Placenta

A disc-shaped temporary organ formed from the trophoblast and maternal endometrium that manages nutrition, gas exchange, excretion, and endocrine functions.

Umbilical arteries

Two vessels that carry deoxygenated blood and waste from the foetus to the placenta.

Umbilical vein

A single vessel that carries oxygenated blood and nutrients from the placenta to the foetus.

Amniotic fluid

A liquid consisting of approximately $99\%$ water that supports the foetus, protects it from physical shock, and maintains temperature.

Amniocentesis

A procedure where amniotic cells are used to check for chromosomal abnormalities.

Parturition

The medical term for birth, describing the expulsion of the foetus, membranes, and placenta from the uterus.

Gestation

The period of pregnancy, lasting approximately 280 days (40 weeks) in humans.

Oxytocin

A hormone from the posterior pituitary that stimulates uterine myometrium contractions during labour.

Prolactin

A hormone from the pituitary gland that stimulates milk production in the mammary glands after birth.

Contraception

The prevention of fertilisation or implantation of a fertilised egg after sexual intercourse.

IUD / IUA (Copper T)

A contraceptive device that prevents a blastocyst from embedding in the endometrium.

RU-486 (mifepristone)

A 'morning-after pill' that blocks progesterone, causing the endometrium to break down and leading to a miscarriage.

HIV (Human Immunodeficiency Virus)

A retrovirus that attacks and destroys CD4+ T-cells, weakening the immune system and leading to AIDS.

Syphilis

An STI caused by the bacterium Treponema pallidum, characterized by stages including a painless chancre and advanced organ damage.

Gonorrhoea

An STI caused by the bacterium Neisseria gonorrhoeae, which can cause discharge, painful urination, and pelvic inflammatory disease (PID).

Infertility

The inability to achieve pregnancy after one year of unprotected intercourse.

IVF (In Vitro Fertilisation)

An assisted reproduction technique where eggs are collected and fertilised by sperm outside the body in a lab before being implanted into the uterus.

GIFT (Gamete Intra-Fallopian Transfer)

A process where egg and sperm are placed together into the fallopian tube so fertilisation occurs inside the body.

ICSI (Intra-Cytoplasmic Sperm Injection)

An assisted reproduction procedure where a single sperm is injected directly into an egg.

FAS (Foetal Alcohol Syndrome)

A pattern of birth defects and cognitive impairment in children caused by maternal alcohol consumption during pregnancy.