What does gametogenesis form in males?
Sperm.
What does gametogenesis form in females?
Ova.
What is insemination?
The transfer of sperm into the female genital tract.
What happens during fertilisation?
Male and female gametes fuse.
What attaches to the uterine wall during implantation?
The blastocyst.
What is parturition?
The expulsion of the fully developed foetus from the mother's body.
Where are the testes located, and how does their temperature compare with body temperature?
They lie in the scrotum, 2–2.5°C below body temperature.
How many seminiferous tubules are in each testicular lobule?
One to three highly coiled tubules.
What do Sertoli cells do for germ cells?
They nourish germ cells.
Which organs and structures make up the female reproductive system?
A pair of ovaries, a pair of oviducts, the uterus, cervix, vagina, and external genitalia.
What do the ovaries produce?
Ova and hormones.
Where does fertilisation occur in the fallopian tube?
In the ampulla.
Which three layers make up the uterus?
The perimetrium, myometrium, and endometrium.
What is spermatogenesis?
The formation of male gametes, or sperm.
When does spermatogenesis begin?
At puberty.
What are the four main parts of a sperm?
The head, neck, middle piece, and tail.
What envelops all parts of a sperm?
A plasma membrane.
What does the sperm head contain?
An elongated nucleus and an acrosome.
How many sperm does a human male ejaculate during coitus?
About 200–300 million.
When does oogenesis begin and end?
It begins during embryonic life and ends at menopause.
When do primary oocytes begin meiosis?
During embryonic life.
Which follicle stages follow a primary follicle during development?
Secondary, tertiary, then Graafian follicles.
Where does the primary oocyte complete meiosis I?
In the tertiary follicle.
What does unequal division produce from the primary oocyte?
A large haploid secondary oocyte and a small polar body.
What is the average interval between human menstrual cycles?
About 28–29 days.
Which phases make up the ovarian and uterine cycles?
Ovarian: follicular, ovulatory, and luteal; uterine: menstrual, proliferative, and secretory.
What causes menstrual flow when fertilisation has not occurred?
The endometrial lining and its blood vessels break down.
What does follicle-stimulating hormone stimulate during the menstrual cycle?
Follicular development and oestrogen secretion by growing follicles.
What triggers rupture of the Graafian follicle and ovulation?
A mid-cycle luteinising hormone surge alongside peak FSH levels.
What does the corpus luteum secrete during the luteal phase?
Progesterone.
Where must sperm and the ovum arrive simultaneously for fertilisation?
The ampullary region.
What blocks additional sperm from entering the ovum?
Membrane changes triggered by sperm contact with the zona pellucida.
What is a zygote?
The diploid cell formed by fusion of the sperm and ovum haploid nuclei.
What are the early cleavage stages of a zygote called?
Blastomeres.
What is implantation?
Embedding of the blastocyst in the uterine endometrium, leading to pregnancy.
Which sex chromosomes do human females have?
XX.
Which sex chromosomes do human males have?
XY.
Which sex chromosome does every human ovum carry?
An X chromosome.
Which sex chromosomes can human sperm carry?
An X chromosome or a Y chromosome.
What proportion of human sperm carry each chromosome type?
50% carry each type.
What sex does an XX human zygote develop into?
A female baby.
What sex does an XY human zygote develop into?
A male baby.
How do chorionic villi and uterine tissue form the placenta?
They interdigitate.
What substances does the placenta exchange for the embryo?
It supplies oxygen and nutrients and removes carbon dioxide and excretory wastes.
Which three germ layers arise from the inner cell mass after implantation?
Ectoderm, mesoderm, and endoderm.
What is the average duration of human pregnancy?
About nine months.
What initiates the foetal ejection reflex at the end of pregnancy?
Signals from the fully developed foetus and placenta.
What does the foetal ejection reflex trigger in the mother?
Pituitary oxytocin release.
How does oxytocin help expel the baby during birth?
It strengthens uterine contractions, which stimulate further oxytocin secretion until the baby is expelled.
What is colostrum?
Milk produced during the first few days of lactation.
How does colostrum help newborn babies?
Its antibodies help develop resistance.
What is gestation?
The duration of pregnancy during which the embryo develops inside the uterus.
How long and wide is each adult testis?
It is 4–5 cm long and 2–3 cm wide.
About how many testicular lobules does each adult testis contain?
About 250 lobules.
What do the male accessory ducts do with sperm?
They store and transport sperm from the testes outside through the urethra.
Which male accessory glands are paired, and which is unpaired?
The seminal vesicles and bulbourethral glands are paired; the prostate is unpaired.
Which nutrients and substances are abundant in seminal plasma?
Fructose, calcium, and certain enzymes.
Which structures connect each ovary to the pelvic wall and uterus?
Ligaments.
What does the outer ovarian cortex contain?
Developing follicles.
What does the myometrium produce during delivery?
Strong contractions.
Which structures are included in the female external genitalia?
The mons pubis, labia majora, labia minora, hymen, and clitoris.
After spermiogenesis, where do sperm heads become embedded before release?
In Sertoli cells.
What provides energy for sperm tail movement and motility?
Numerous mitochondria in the middle piece.
When are oogonia formed?
During foetal life.
How many primary follicles remain in each ovary at puberty?
About 60,000–80,000.
What happens to the follicles and endometrium during the proliferative phase?
Follicles grow toward a mature Graafian follicle, while the endometrium regenerates through proliferation.
What happens after fertilisation does not occur?
The corpus luteum degenerates and the endometrium disintegrates, leading to menstruation.
What does the secondary oocyte produce after completing meiosis II?
A second polar body and a haploid ovum.
What is an embryo with 8–16 blastomeres called?
A morula.
What does the trophoblast do when the blastocyst reaches the endometrium?
It attaches to the endometrium.
Which hormones does the placenta produce as endocrine tissue?
hCG, human placental lactogen, oestrogens, and progestogens.
What connects the placenta to the embryo and transfers substances?
The umbilical cord.
What develops by the fifth month of human pregnancy?
Hair appears on the head, and the foetus makes its first movements.
Which maternal hormone levels increase several-fold during pregnancy?
Oestrogens, progestogens, cortisol, prolactin, and thyroxine.
What happens to the placenta soon after the infant is delivered?
It is expelled from the uterus.
When do mammary glands differentiate and begin producing milk?
They differentiate during pregnancy and begin producing milk toward its end.
Answer 37 questions on Human Reproduction.
1. What is the process called in which males form sperm and females form ova?
2. During which reproductive process are sperm transferred into the female genital tract?
Go over the full study guide for Human Reproduction.
Read the study guide →Upload your class notes and Revizly writes your flashcards in about a minute.
Flashcard maker