Male & female reproduction

Question 1

Why is the female reproductive system important?

Answer 1

• To produce offspring
• reception of sperm
• childbirth
• Providing a suitable environment for foetal development

Question 2

Name the ligaments that hold the uterus in place

Answer 2

Broad ligament
Ovarian ligament
Round ligament
Uterosacral
suspensory

Question 3

What are the function of the ovaries

Answer 3

• To hold the ovas that a woman has for life
• To produce sex hormones e.g., oestrogen
• Complete menstruation

Question 4

Describe the structure and function of fallopian tubes

Answer 4

Fallopian tubes are made of several sections: ampulla, isthmus, infundibulum & fimbriae
They are not joined to the ovary & are the site of fertilization, roughly 10cm long
Fertilization occurs in the ampulla
Fimbriae contain cilia which beat in a rhythm to move the egg towards the uterus, this takes 5 days

Question 5

What is uterine position known as?

Answer 5

Ante vertebral

Question 6

What is the top of the uterus called

Answer 6

The fundus

Question 7

What are the 3 layers that make up the uterus

Answer 7

Endometrium (inner layer where egg embeds itself)
Myometrium (middle muscular layer)
Perimetrium (outer protective layer)

Question 8

Where is the location of the uterus?

Answer 8

It is found within the pelvic cavity protected by pelvic bones.
It is anterior to the rectum & posterosuperior to the bladder

Question 9

Define the menstrual cycle

Answer 9

A collection of cyclical changes that occur in the uterus & ovaries over a 28 day period

Question 10

What occurs between day 1-5 in the menstrual cycle

Answer 10

This is where menstruation occurs, the endometrium is shed, 50-150ml of blood is lost approximately, progesterone levels are low & oestrogen steadily increases

Question 11

What occurs between day 4-13?

Answer 11

The endometrium begins to build back up again, spiral arteries develop which temporarily supply blood to endometrium, receptor cells become primed, this is known as the proliferation phase

Question 12

What occurs on day 14

Answer 12

This is ovulation, where an egg is released from the ovaries, Hormones of LH & FSH reach their peak during ovulation.
You are most fertile during this period, cervical mucus aids in entry & survival of incoming sperm

Question 13

What occurs between day 15-28?

Answer 13

This is known as the secretory phase, spiral arteries begin to develop more & twist, receptor cells secrete glycogen to support a possible embryo

Question 14

What happens if not fertilization occurs?

Answer 14

The cycle repeats itself. The corpus luteum breaks down becomes corpus albican, progesterone production is reduced, blood supply to endometrium is cut via breakdown of spiral arteries. Endometrium gets ready to be shed

Question 15

What are the functions of: FSH, LH, Oestrogen & Progesterone

Answer 15

FSH: follicle-stimulating hormone which stimulates the maturity of an egg & initiates follicular growth
LH: Luteinizing hormone, stimulates the release of an egg from an ovary, it triggers ovulation & oestrogen & progesterone production
Oestrogen: causes the thickening of the uterine lining & improves lubrication of vagina
Progesterone: Responsible for the maintenance of the endometrium, prepares uterus for implant, stimulates growth of new BV upon fertilization/implantation

Question 16

What are the 2 cycles that occur within the menstrual cycle?

Answer 16

Ovarian cycle
Uterine cycle

Question 17

What is the difference between the ovarian cycle & the uterine cycle

Answer 17

Ovarian Cycle: Describes changes in the follicle, controls egg production, and involves cyclic release of estrogen and progesterone.
Uterine Cycle: Governs preparation and maintenance of the uterine lining (endometrium) to receive an embryo

Question 18

Describe the stages in the ovarian cycle

Answer 18

The ovarian cycle consists of a luteal & follicular phase
The follicular phase occurs between day 1-14,
It involves granulosa cells which accumulate fluid creating an antrum, this transforms primary follicle to Graafian follicle.
It involves slow rise of FSG & LH causing follicle growth on the ovary surface, which develops into a Graafian follicle. This stimulates the production of oestrogen. Once a follicle reaches 30-60 cells it is referred to as a morula. Increased oestrogen causes a surge in LH leading to ovulation
Ovulation occurs at day 14, if implantation does not happen endometrium is shed. Enlargement of follicle & rupture occurs oocyte is expelled. Rise in oestrogen, surge of LH, less FSH. Before ovulation, there is a drop in oestrogen & a surge of progesterone
No LH surge then no ovulation
The luteal phase: This phase leads to formation of corpus luteum. Occurs between day 15-28
remainder of follicle is penetrated by fibroblasts from the theca, corpus luteum of formed creating secretion of oestrogen & progesterone. Corpus luteum degenerates after 10 days

Question 19

Describe the stages in the uterine cycle

Answer 19

The uterine cycle refers to the changes in the endometrium during menstruation, there are 3 phases
Menstruation: occurs day 1-5, endometrium is broken down due to drop in hormones, ovarian hormones are at their lowest, endometrium remnants passes out of vagina/cervix in blood flow
Proliferation: Day 6-14, occurs during the follicular phase of the ovarian cycle , when the endometrium begins to proliferate. endometrium is exposed to oestrogen from developing follicle. Blood vessels & glands begin to form
Secretory: Day15- 28, occurs during the luteal phase of ovarian cycle. Endometrial glands secrete glycogen to support possible embryo. There is increased vascularisation & the corpus luteum breaks down if there is no fertilisation creating progesterone levels to drop. This causes endometrial cells to die so endometrium breaks down & cycle repeats itself

Question 20

Describe the hormones involved in pregnancy

Answer 20

Oestrogen- enlargement of external genitalia & softening of pelvic ligaments

Progesterone-thickening of uterine wall, inhibits uterine contractions, development of alveoli in mammary glands

HCG- acts like LH to maintain corpus luteum, prevents menstruation,

Prolactin- stimulates milk production after fall of oestrogen, Inhibits FSH & ovulation after childbirth

Relaxin-produced to increase flexibility of tissues

Oxytocin- stimulates uterine contractions, allows bond to be made between mother & child

Question 21

Describe the process of fertilisation

Answer 21

Fertilisation is defined as the fusion of male & female gametes forming a zygote, a diploid cell with a chromosomal number of 46.
1. Penetration of corona radiata & zona pellucida (coat that surrounds the egg) Enzymes are released to allow passage of sperm through corona radiata
The acrosome of a sperm contains digestive enzymes that digest the zona pellucida creates changes to the sperm cell to allow capacitation, flagellum allows them to swim towards egg.
2. Fusion of membranes: egg cell moves to edge of plasma membrane triggering depolarization of cell, this prevents polyspermy via release of calcium ions, The formation of the fertilization cone enables fusion between the membranes of both the egg and the sperm, allowing passage of the sperm’s head into the egg. Simultaneously, thanks to depolarization and the release of cortical granules, the entrance of multiple sperm is prevented.
3. Zygote formation: genetic information in sperm fuses with egg nucleus to complete fertilisation forming a zygote

Question 22

Define polyspermy

Answer 22

Binding of more than one sperm to the egg, results in no viable zygote due to 2 copies of each chromosome
Depolarization of the cell membrane of the fertilized egg and release of calcium ions to prevent polyspermy (fertilisation of more than one sperm)

Question 23

Name the stages of development to a foetus

Answer 23

1. Zygote (diploid cell)
2. Morula (cluster of cells)
3. Blastocyst (inner cell mass that differentiates, day 4-20)
4. Embryo (21-56 days)
5. Foetus (9 weeks +)

Question 24

What are the main functions of the male reproductive system?

Answer 24

• produce sperm
• produce testosterone
  -production of gametes
• transport of sperm to female

Question 25

Name and describe the ducts involved in the male reproductive system

Answer 25

1. Epididymis: found above the testes, it stores sperm until ejaculation, it is 4cm long & lies on either side of the testes, sperm can be stored for months. but are eventually phagocytized, contraction of smooth muscle causes movement of sperm from the epididymis to the van deferens. 2. the Ductus Van Deferens: Involved in transporting sperm from the epididymis to the urethra, 45cm long, forms an ampulla at its terminal to lead into the ejaculatory duct, it propels sperm in peristaltic motions. 3. Ejaculatory duct: This delivers sperm into the urethra, 4. The urethra: opens to the outside to deliver sperm into the female, the urethra carries both semen & urine & consists of 3 components

Question 26

Name & describe the 3 components of the urethra

Answer 26

1. prostatic urethra: surrounded by the prostate, it provides a passage of urine through the prostate 2. Membranous urethra: The membranous urethra is the narrowest and tightest part of the urethra, so it helps you hold urine in. It’s surrounded by a circular muscle called a sphincter. The muscles tighten when you need to hold urine and relax when you’re ready to urinate 3. Spongy urethra: runs through the penis into external urethral surface, provides passage for urine & semen out of the body

Question 27

Define the function & importance of sertoli cells

Answer 27

Sertoli cells produce sperm and are important for spermatogenetic functions: - nourish sperm - form 60 proteins involved in spermatogenesis - Consume cytoplasm after spermatogenesis - Provides a stable environment for sperm production

Question 28

What are the 3 cell types found in the testes and their function?

Answer 28

Germ cells- are stem cells involved in spermatogenesis, give rise to production of gametes Stromal cells- regulate spermatogenesis Leydig cells- produce testosterone

Question 29

Describe the structure of the testis

Answer 29

The testes are surrounded by 2 tunics: tunica vaginalis (facilitates smooth movement of the testes) & tunica albuginea (fibrous, helps maintain an erection via constriction of veins in the penis) septa extend from tunic albuginea and divide the testes into 250 wedge-shaped lobules. Each lobule has 4 seminiferous tubules (sperm factories)

Question 30

Name & describe the 3 sex glands

Answer 30

1. Seminal- produces seminal fluid, mix sperm with semen, provides fructose to sperm, causes semen to coagulate and stick to inner walls of vagina 2. Prostate- found at the base of the bladder, secretions via prostatic urethra when smooth muscle contracts. It aids in urine & sperm transport to urethra. Secretions contain enzyme fibrinolysin which liquidifies sperm aiding in swimming 3. Bulbourethral- (cowper gland) (lubricates the passage for ejaculation, produces pre-cum fluid to help with smooth ejaculation), located below the prostate, produces thick mucus which runs into the urethra, neutralizes acidic urine in urethra before ejaculation

Question 31

Describe the location & function of the scrotum

Answer 31

It is located around the testes, is a sack of skin covered with hairs, a septum divides the 2 testes. Scrotum/testes found hanging outside the body, temperature is 3 degrees cooler to produce and store viable sperm. Sperm need cool conditions to protect DNA within, mobility efficiency & efficient production

Question 32

Describe the function of the cremaster muscle & Dartos muscle

Answer 32

Cremaster & dartos involved in keeping testes drawn close to the body when it cold to maintain optimum temperature for sperm production & storage Dartos- a layer of smooth muscle found in the foreskin, it wrinkles the scrotum surface, reducing SA for heat to be lost from Cremaster-These are bands of skeletal muscle that contract when its cold to elevate the testes towards the abdominal cavity

Question 33

Define the purpose of the penis

Answer 33

To deliver sperm into the female tract, it consists of a shaft, covered by a prepuce (foreskin) contains the glans right at the tip, the urethra is found running down the centre Contains lots of blood vessels to create an erection

Question 34

What prevents mixing of urine & sperm during ejaculaion

Answer 34

Bladder sphincter prevents ejaculation of sperm into the bladder Failure of bladder sphincter is known as retrograde ejaculation

Question 35

Describe the process of spermatogenesis

Answer 35

1. Production process begins during puberty within the seminiferous tubules within the testes 2. Endocrine cells (leydig) lying between the tubules secrete testosterone 3. Spermatogonia divide via mitosis to maintain germ cell line (passing of genes to sperm cell) 4. Some become primary spermatocytes which undergo meiosis 1 to produce 2nd spermatocyte 5. secondary spermatocytes undergo meiosis 2 each producing 2 haploid spermatids 6. Spermatids are converted to viable sperm, cytoplasm is stripped away, acrosome & flagellum produced 7. Sertoli cells form a blood barrier, nourish the sperm, moves them towards end of tubules, & secrete fluid for them to swim in

Question 36

Describe the function of semen

Answer 36

Transports sperm in a mixture, 2-5ml of semen is ejaculated by contains 50-130 million sperm, sperm must reach fallopian tubes, and only viable for 48hrs Passage to fallopian tubes is made easier by ejaculation as it propels sperm at 500cm/s Female orgasm also aids in propulsion

Question 37

Describe the location & function of the corpus spongiosum

Answer 37

It enwraps the urethra and protects it from being squeezed and closed during erection. It prevents the urethra from pinching closed, maintaining it as a viable channel for ejaculation. The spongy urethra travels throughout its length, and cavernous spaces in the corpus spongiosum fill with blood during erection to allow for ejaculation

Question 38

Describe the location & function of the corpus cavernosa

Answer 38

It is filled with erectile tissue, nerves, blood vessels, and muscle fibers. It pairs with the spongiosum, runs on dorsal surface, The cavernosa allows blood to flow in, making the penis hard during sexual intercourse. It facilitates penile erections. The corpora cavernosa help maintain erections by preventing blood return from the penis.

Question 39

What is a spermatid

Answer 39

The spermatid is the haploid male gametid that results from division of secondary spermatocytes. As a result of meiosis, each spermatid contains only half of the genetic material present in the original primary spermatocyte.

Question 40

What is the function of cervical mucus

Answer 40

Secreted by the endocervical glands - helps sperm move through the cervix to reach egg during ovulation - to prevent other substances or sometimes sperm from passing into the cervix