Fertilization - Embryology Note #1

Vocabulary flashcards covering key terms related to fertilization and embryology from the provided notes.

Vagina

Lower part of the female reproductive tract; a muscular tube lined with mucous membrane that receives semen and connects to the cervix.

Cervix

Lower third of the uterus; a narrow canal linking the uterus with the vagina; lined with mucous; mucus viscosity changes during the menstrual cycle.

Uterus

Pear-shaped muscular organ (about 3 inches) where a pregnancy develops; connected to the Fallopian tubes and cervix.

Fallopian tubes

Pair of tubes that conduct ova from the ovaries to the uterus; the ovarian end opens into the abdominal cavity with fimbriae.

Fimbriae

Finger-like projections at the ovary-adjacent end of the Fallopian tubes that help direct the ovum into the tube.

Ovary

Female sex organs containing numerous follicles; release an ovum during ovulation after Graafian follicle maturation.

Graafian follicle

Mature follicle that releases an ovum during ovulation; first meiotic division yields a secondary oocyte and first polar body.

Primary oocyte

Oocyte formed during fetal development; begins meiosis I but pauses until puberty.

Secondary oocyte

Result of the first meiotic division; viable for fertilization; accompanied by a first polar body.

Definitive ovum

Mature haploid ovum with 23 chromosomes ready for fertilization.

Polar body

Small, nonfunctional cells formed during meiosis; reabsorbed.

Estrogen

Hormone produced during the early to mid-cycle (roughly days 1–14) that stimulates uterine glands.

Lysosome

Organelles in the oocyte; fuse with the oocyte membrane during fertilization to release enzymes that help penetrate the zona pellucida.

Seminal vesicles

Glands that contribute 60–70% of seminal fluid; secrete fructose, prostaglandins, and coagulase.

Prostate gland

Gland contributing 30–40% of seminal fluid; secretes citrate, fibrinolysin, PSA, seminal plasmin, and seminal relaxin.

Fructose

Carbohydrate fuel in semen used by sperm for energy.

Prostaglandins

Chemicals in semen that can induce uterine contractions and aid sperm movement.

Coagulase (vesiculase)

Enzyme from seminal fluid that coagulates semen to help sperm adhere initially.

Citrate

Ketoacid intermediate and energy source component of seminal fluid from the prostate.

Fibrinolysin

Enzyme that breaks down coagulated semen to allow sperm entry.

PSA (Prostate-Specific Antigen)

Marker in semen; used clinically to indicate prostate health (e.g., can indicate BPH).

Seminal plasmin

Antibacterial enzyme in semen that helps keep the female tract sterile.

Seminal relaxin

Hormone in semen that increases sperm motility through the female tract.

Acrosome

Cap containing enzymes (e.g., acrosin) that aid in penetrating the zona pellucida during fertilization.

Head of sperm

Contains the nucleus with 23 chromosomes and the acrosome.

Mid piece

Section rich in mitochondria supplying ATP for flagellar movement.

Flagella

Tail of the sperm with a 9+2 microtubule arrangement enabling propulsion.

9+2 microtubule arrangement

Structural arrangement in the flagellum: nine outer doublets with two central singlet microtubules guiding movement.

Capacitation

Maturation process in the female tract that removes surface proteins from the sperm and enables hypermotility and acrosomal readiness.

Acrosomal reaction

Calcium-triggered release of acrosomal enzymes (e.g., acrosin) that allow sperm to penetrate the zona pellucida.

Fast block to polyspermy

Immediate depolarization of the oocyte membrane after sperm entry, preventing additional sperm from fusing.

Slow block to polyspermy

Calcium-mediated cortical reaction that hardens the zona pellucida and completes meiosis II of the oocyte.

Zona pellucida

Glycoprotein layer surrounding the oocyte; site of sperm binding during fertilization.

ZP3 receptor

Zona pellucida receptor that sperm binds to during the acrosomal reaction.

Fertilization

Union of a definitive ovum and a sperm to form a zygote.

Retropulsion

Uterine contractions induced by prostaglandins that move sperm toward the Fallopian tubes.