M3 Reproductive Flashcards
Where is sperm produced?
Seminiferous tubules
What are gonads?
Ovaries in female and testis in male
Describe the sperm’s pathway from production to storage
The sperm is first produced in the seminiferous tubules, it is then directed in to the rete testis, where it is distributed into the efferent tubules and enters the epididymus. The immature sperm passes through the head, body and tail of the epididymus where it is stored till ejaculation.
Muscle activity and the pampinform venous plexus helps to maintain the cooler temperature of the testis, how do they do that?
- The scrotum’s wrinkled exterior decreases surface area and increases thickness, improving insulation and prevents heat loss.
- the dartos and cremaster muscles can contract and pull the testis upwards and relax to regulate the temperature in response to cold or fear.
- the pampinform venous plexus coils around the testicular artery, cooling the arterial blood before it enters the testis.
Describe the sperms journey through the epididymis
Immature, non-motile sperm moves slowly along the duct of the epididymis through a fluid that contains antimicrobial proteins. Takes around 20 days. During which the sperm gains the ability to swim.
What is the structure of the epididymis
Head, body and tail
Head is made up of the efferent ductules.
The duct of the epididymis completes the head and makes up the body and tail
What are the 2 functions of the stereocillia on the epididymal epithelium?
- To absorb excess testicular fluid
- To pass nutrients to sperm stored temporarily in the lumen
What are the 2 major functions of Meiosis in females?
- Reduction of chromosome number: from diploid to haploid
- Genetic variation
How are reproductive hormones produced in females?
How are reproductive hormones regulated in females?
What are the functions of reproductive hormones in females?
Describe how the Hypothalamic-Pituitary-Gonadal (HPG) axis regulates female hormone production
Identify hormones produced in the menstrual cycle
Describe the phases of the menstrual cycle.
Uterine:
1. Menstrual phase: Gn rises, functional layer of endometrium shed
2. Proliferative phase: LH surge and FSH rise before ovulation, rising estrogen and functional layer regenerates
3. Secretory phase: LH drop remains enough for progesterone production. Progesterone functions
Ovarian:
1. Follicular phase: Follicular development
2. Luteal phase: Corpus Luteum development
Describe the function of the Fimbrae
Brush the ovulated oocyte into the infundibulum.
What does the ovary contain?
Follicles
Stromal matrix (nerves/blood vessels/connective tissues)
Tunica albuginea
Surface epithelium
What are the stages of follicular maturation?
- Primordial Follicle
- Primary follicle
- Secondary follicle
- Pre-antral follicle
- Antral follicle
- Ovulation (antral follicle ruptures)
- Corpus luteum
What is antrum?
Fluid-filled spaces in the follicle.
What is the purpose of granulosa cells?
- Produce hormones (estrogen)
- Protects con-growing follicles
What is the purpose and functions of progesterone?
To maintain pregnancy
1. Limits Fimbrae movement and smooth muscle contraction.
2. Promotes blood supply and endometrial glands to provide nutrient-rich secretion for implantation
3. Thickens the cervical mucus to block entry of more sperm, pathogens or debris.
At what stage in Oogenesis is Prophase I?
The oocyte arrests in prophase I, where the oocyte has undergone recombination, but the follicle cannot develop further till puberty (Still diploid).
At what stage in Oogenesis is Metaphase I?
Enters metaphase I at Meiosis I, Polar body discarded.
This happens during ovulation, at the end of Metaphase I, the chromosome is pulled apart. Haploid
At what stage in Oogenesis is Metaphase II
Begins Meiosis II but arrests in Metaphase II. It only completes after fertilisation.
Compare and contrast Spermatogenesis and Oogenesis (6)
- S takes around 74 days, O takes 13-50 years.
- S occurs from puberty to old age, O occurs from fetal life to menopause.
- S produces 4 sperm, O produces 1 ovum and 2-3 polar bodies.
- S can produce over 1 trillion sperm, O can only produce less than 500 ovum
- S has 5% error rate, O has a 20% error rate.
- S has 1 sustentocyte that sustains many spermatocytes, O has many granulosa cells sustaining 1 oocyte.
Compare and contrast Male and female reproductive systems (6)
- M: Gonads outside of the body, F: gonads inside the abdominal cavity
- M: Gonads continuous with reproductive tract, F: not continuous.
- M: release of gametes continuous, F: Monthly
- M: only 1 gonadal steroid (testosterone), F: 2, estrogen + progesterone
- M: Does not prepare for a newborn, F: prepares for a newborn.
- M: Gametes are replenished throughout life, F: Gamete is finite, exhausted by menopause.
what is the function of Sertoli cells?
Produce Androgen binding protein when stimulated by FSH, keeping testosterone level high to maintain spermatogenesis.
Produce Inhibin, decreasing FSH release.
What is the function of Leydig cells?
Stimulated by LH and produce Testosterone which then binds to ABP released by the Sertoli cells
What does testosterone trigger in spermatogenesis?
Negative feedback to the anterior pituitary stops FSH, LH and GnRH release.
What is produced in the seminal gland?
Semen: Fructose sugar, Coagulating enzyme, Prostaglandins, citric acid
