The Reproductive System Flashcards
What is the function of the reproductive system?
to produce, store, nourish and transport male and female gametes
What are the testes made up of?
a series of lobules
What is spermatogenesis and where does it take place?
Spermatogenesis is the process of forming sperm, this takes place in the testes.
Describe the process of spermatogenesis
- The process begins in the outermost layer of cells and proceed towards the lumen
- Seminiferous tubules merge into straight tubules
- Merge to from rete testis which connect to the epididymis
Describe the three processes of spermatogenesis in detail?
- Mitosis
○ Spermatogonium divides – one daughter cells remains in situ, the other moves towards the lumen of the ST
○ Differentiates into primary spermatocyte
*Meiosis
○ Division of spermatocyte produces spermatids - Spermiogenesis
○ Spermatids
differentiate into physically mature spermatozoa
Describe the structure of a sperm
- Head
○ Contains nucleus with densely packed chromosomes
○ Acrosome – contains enzymes essential to fertilisation - Midpiece
○ Contains abundant mitochondria- what gives cells energy allowing themm to swim to the fallopian tube - Tail
○ Flagellum- the only example of a flagellum in the human body
What is the significance of acrosome in the head of the sperm?
it allows the sperm to break down the surface of the egg to allow the chromosomes to mix
Why do sperm not have an ER, Golgi apparatus or lysosomes etc?
Reduces size and mass this means there are no stores of glucose etc so respiration cant occur.
How do the sperm respire?
as they do not have any energy stores they must absorb fructose from fluid
Name three accessory glands in the male reproductive system
- Seminal vesicle
○ 60% volume of semen
○ Fluid contains high conc. of fructose- food source
○ Slightly alkaline- Alkaline seminal fluid neutralises acid secretions of prostate and vagina - Prostate gland
○ 20-30% volume of semen
○ Encircles urethra
○ Contains
seminalplasmin- protein with antibiotic properties, prevents infection in males - Bulbourethral gland
○ Produce thick, alkaline mucus
○ Neutralises any remaining urinary acids
What is the purpose of testosterone in men?
○ Maintains libido
○ Stimulates osteogenesis and myogenesis- governs bone and muscle production helps increase their bone and muscle mass
○ Maintains male secondary sex characteristics- beards etc
○ Maintains male accessory glands
What is the function of the female reproductive system?
- Produces sex hormones and gametes
- Also protects and supports developing foetus
Where does Oogenesis occur?
In the ovaries
Describe the structure of the ovaries
- Pair of small, lumpy, almond-shaped organs
○ Ovarian ligament stabilises their position relative to the uterus - Produce oocytes (eggs)
○ Oogenesis
What is the function of the ovaries?
To secrete female sex hormones
What is the process of Oogenesis?
- Oogonium divides by mitosis to produce primary oocytes
- Primary oocytes prepare to undergo meiosis – proceed to meiosis 1
- Held in suspended development until puberty
- Rising levels of FSH at puberty trigger the ovarian cycle
- Some primary oocytes complete meiosis I to form secondary oocytes
- Secondary oocytes leave ovary suspended in metaphase of meiosis II
- Meiosis will not be completed until fertilisation occurs
What happens to the cells after puberty?
They mature.
Cells are held in prophase of meiosis 1 until puberty – occurs between 3rd and 7th month of foetal development
What is the follicular phase?
producing and releasing a viable egg
what events take place during the follicular phase?
- Primary oocytes in outer portion of ovarian cortex in egg nests – forms primordial follicle with follicle cells
- Primary follicle develops – follicular cells divide to produce granulosa cells
- Layer of thecal cells develops around follicle
- Mature graafian follicle formed – LH levels rise and primary oocyte completes meiosis I
- At ovulation, secondary oocyte released from graafian follicle into fallopian tube
- Follicle cells divide to from several layers of cells surrounding the oocyte
- Thecal cells and granulosa cells produce oestrogen
- Mature graafian follicle or tertiary follicle formed after 10-14 days of the cycle
What events take place during the luteal phase?
- Empty graafian follicle collapses and develops into corpus luteum (CL) – endocrine function
○ Cholesterol in CL used to synthesise progesterone
○ Prepares uterus for pregnancy - CL degenerates if fertilisation doesn’t occur
○ Progesterone and oestrogen levels fall - If fertilisation occurs, CL continues to produce progesterone which maintains uterine lining
- Placenta eventually takes over progesterone production and CL degrades
- CL degenerates about 12 days after ovulation unless fertilisation occurs
What is the luteal phase?
preparing the uterus for fertiliasation
What are the three phases of the uterine cycle?
-menses
-proliferative phase
-secretory phase
What is an antrum?
the expanding central chamber of the follicle, fills with fluid
What is the function of the uterus?
- Protects, nourishes and removes wastes from the developing foetus
What is menses?
Menstruation
○ Degeneration of endometrium
○ Sloughing off of tissue
What happens during the proliferative phase?
Oestrogens secreted by developing follicles stimulate growth
What happens during the secretory phase?
Progesterone makes the endometrium receptive to implantation of the blastocyst
What happens to the male reproductive system with age?
- Andropause
this is where levels of circulating testosterone fall, also FSH and LH levels
-However sperm production continues
What happens to the female reproductive system with age?
- Menopause
-Ovulation and menses cease
-Levels of circulating oestrogen, progesterone, FSH and LH fall
-Osteoporosis can develop
