Reproduction: Female anatomy and development Flashcards
What is the anatomical structure of the sperm cell? (3)
Head: chromosomes and acrosome
Midpiece: mitochondria
Tail: flagellum
What is the process in spermatogenesis? (5)
- Spermatogonium
- Chromosomes replicate - 2 1st spermatocytes (2n)
- Meiosis 1 - 2 2nd spermatocytes (2 x n)
- Meiosis 2 - 4 spermatids (1 x n)
- Differentiation - spermatazoa (1 x n)
Where does spermatogenesis occur in the testis?
Basement membrane to lumen
How long does it take sperm to mature? (3)
- 20 days
- move to epididymis and acquire motility
- move and stay in vas deferens until ejaculation
What are the sexual responses in males and what are they controlled by? (5)
Controlled by: autonomic nervous system - Spinal reflexes - Phases > Erection - Parasympathetic NS > Emission - sympathetic NS > Ejaculation - sympathetic NS
What happens when a male comes across a stimulus? (2)
- Mechanoreceptors of penis and erogenous zones
- Descending signals from higher brain centers
What are the steps in emission within a penis? (5)
- Response to mechanical stimulation continues
- Neural activity shifts from PS to S control
- Contractions of epididymis, vas deferens and ejaculatory duct
- Secretions from seminal vesicles and prostate
- Result - movement of semen into urethra
What is the average sperm count and when are you considered infertile?
Average volume of semen - 2.75ml
66million sperm/ml
180million sperm
Infertile = < 20 million/ml
What are the functions of the female reproductive tracts? (6)
- Production of the egg
- Reception of sperm
- Transport of the sperm and ovum to common date for union
- Maintenance of the developing fetes until it can survive in the outside world
- Giving birth
- Nourishing the infant after birth
What are characteristics of the female reproductive system? (3)
Cyclic changes in activity (menstrual cycle)
Restricted periods of fertility - ovulation
Limited gamete production
What are the female reproductive organs? (3)
Ovaries - site of ova maturation
Reproductive tract - uterus, uterine tubes, vagina
External genitalia = vulva
What are follicles? (3)
Contain 1 ovum
Develop in ovary
Starts as primordial follicle (oocyte, granulosa cells)
What are granulosa cells? (5)
Target cells of oestrogen and FSH
Secrete inhibin - provides negative feedback to FSH
Transport nutrients to oocytes through gap junctions
Secrete oestrogen’s
Can turn into theca cells
What is the structure of the vagina? (4)
Female organ of copulation
Wall contains smooth muscle
Inner surface bathed in acid fluid secreted from uterus
Protects against bacterial infections
What is the structure of the uterus and what does it do? (5)
Site of fetal development
Cervix - canal leading to vagina
Outer layer - perimetrium (epithelial)
Middle layer - myometrium (smooth muscle - thick)
Inner layer - endometrium ( epithelial etc)
What are uterine tubes also known as?
Fallopian tubes or oviducts
What is the role of the uterine tubes? (3)
- Ova is transported from ovaries to uterus
- Site of fertilisation
- Peristalsis contractions
What is the process of egg development? (2)
Oogenesis – oogonia –> ova
Number of oogonia fixed prior to birth
What are the steps in oogonia? (3)
- Fetal - Oogonia undergo mitosis, primary oocyte forms
- Prior to ovulation - meiosis 1, secondary oocyte forms
- After fertilisation - meiosis 2, ovum formed
What cycles occur in the menstruation cycle? (2)
Ovarian cycle
Uterine cycle
Caused by changes in oestrogen and progesterone
What is the ovarian cycle? (2)
Pre ovulatory: follicular phase = oestrogens (days 1-14)
Post ovulatory: luteal phase = progestins days (14-28)
What is the follicular phase and how long does it last?
Menstruation –> ovulation
roughly 14 days
What is the luteal phase and how long does it last?
Ovulation –> Defoe menstruation
14 days
What occurs in the uterine cycle made up of? (3)
Menstrual phase: 1-5 days
Proliferative phase: day 14
Secretory phase: 15-28 days
What happens in the follicular phase? (4)
- Follicles begin to develop from primordial follicles
- oocyte grows
- Dominant follicle continued development
- Corona radiata develops
What is a graafian follicle?
A mature follicle
What are the features of a Graafian follicle (6)
Theca cells Antrum Corona radiata zona pellucida Oocyte Cumulus oophorus
What happens at ovulation? (5)
- Wall of Graafian follicle ruptures
- Antra fluid with oocyte flows to ovary surface
- Released
- Ova enters fimbrae
- LH surge triggers ovulation and development of corpus lute in luteal phase
What happens in the luteal phase? (4)
> Ruptured follicle –> gland = corpus luteum
Corpus luteum secretes estrogens and progesterone
Corpus luteum reaches max activity 10 days, then degenerates
Degeneration –> decrease oestrogen’s and progesterone –> menstruation
What are fraternal twins? (3)
- 2 of more follicles may become dominant and released at ovulation
- if both fertilised, fraternal twins
- dizygotic twins (2 zygotes)
What happens in the uterine cycle menstruation phase? (4)
- Shedding of uterine lining
- Blood flow to tissue decreases
- Tissues die and go into vagina - blood
- Triggered by decreased hormone
What occurs in the proliferative phase? (7)
- Uterus prepares for fertilised ovum
- Endometrial lining develops
- Endometrial layer grows
- Endometrial glands enlarge
- Smooth muscle layer thickens
- Cervical glands secrete mucus
- Estrogen stimulate development of uterine lining
What is the secretory phase? (4)
Endometrium prepared for implantation
Blood supply increased
Glands enlarge and secrete glycogen rich fluids
Cervical secretions more sticky forming a plug
What hormones are involved in the menstrual cycle and where are they secreted from? (3)
Estrogen - follicle then corpus luteum
Progesterone - corpus luteum
LH and FSH - anterior pituitary
What do estrogens and progesterones inhibit?
LH and FSH
What is FSH role during mid-follicular phase? (2)
Granulosa cells –> theca cells
Theca cells have LH receptors
What is estrogens role during mid-follicular phase? (2)
LH receptors on granulosa cells
Progesterone receptors on endometrial cells
What are the long term regulators of female reproductive function? (3)
Puberty - estrogen
Reproductive years - maintain sex characteristics
Menopause - estrogen levels decrease
