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Making Babies. 6.6 Human Reproduction. http://www.images-photography-pictures.net/baby-picture-quiet-childish-david-baby.jpg. The Male plumbing. Do you think you know it? Try to label all the bits……. http://www.student.loretto.org/anatomyphys/Keydiagram-male--ReproductiveSystem.jpg.
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Making Babies 6.6 Human Reproduction http://www.images-photography-pictures.net/baby-picture-quiet-childish-david-baby.jpg
The Male plumbing • Do you think you know it? • Try to label all the bits…… http://www.student.loretto.org/anatomyphys/Keydiagram-male--ReproductiveSystem.jpg
Check your answers 1 Vas deferens 2 Seminal vesicle 3 Prostate gland 4 Cowper's glands 5 Epididymis 6 Testis 7 Scrotum 8 Penis 9 Pubic symphysis 10 Bladder 11 Urethra
The Female plumbing http://www.student.loretto.org/anatomyphys/Keydiagram-female--ReproductiveSystem.jpg
Check your answers? 1 Ovary 2 Fallopian tube 3 Uterus 3a Cervix 4 Vagina 5 Clitoris 5a Prepuce 6 Labia magora 7 Labia minora 8 Pubic symphysis 9 Bladder 10 Anus 11 Perineum
What do the bits do? Lets take a “day in the life of a sperm”! • Sperm cells are made in the testis. The testes make 300,000,000 sperm a day. (Which type of cell division do they use?) They work best at 33-34oC They also produce Testosterone. A male has about 250m of tubes in their testes to make sperm. 2. Once made they are stored in the Epididymus (about 35m long) until they’re needed. http://www.e-rham.com/img/atcl4_testes.gif
A Sperm cell. Think about how it’s structure lets it do its job. What does the Acrosome do? What is special about the nucleus of a sperm cell? Why does it need so many mitochondria? Try to find a movie of a sperm swimming. What could you use to model this? http://wpcontent.answers.com/wikipedia/commons/thumb/0/03/Complete_diagram_of_a_human_spermatozoa.svg/350px-Complete_diagram_of_a_human_spermatozoa.svg.png
The average volume of semen for each ejaculation is 2.5 to 6ml and the average range of sperms ejaculated is 50 to 100 million/ml(How many sperm per ejaculate?) Seminal Vesicles add Semen • These are two bags located between the bladder and the rectum. They produce a thick alkaline fluid and pass it into the ejaculatory duct. This secretion keeps the sperm alive makes up about 60% of the volume of semen. • Semen is a mixture of sperm and the secretion of various glands, the seminal vesicles, prostate glands and the bulbourethral gland. http://www.medindia.net/patients/patientinfo/images/prostate-gland.jpg
The Prostate Gland • This controls which tube is connected to the urethra- from the bladder or from the Vas Deferens. It is normal for a man to be unable to urinate while sexually aroused! Prostate cancer tends to develop in men over the age of fifty and although it is one of the most prevalent types of cancer in men, many never have symptoms, undergo no therapy, and eventually die of other causes. http://jbooy.files.wordpress.com/2008/11/prostate_enlarged_z.jpg
The Penis • Average size? http://v-more.com/imgz/standart/1193460436484.gif The engorgement of the corpus cavernosum and subsequent erection is triggered by a short-lived neurotransmitter, nitric oxide. A clitoris has as many nerve endings as are found in the Glans penis, just packed more closely. http://en.wikipedia.org/wiki/File:Penis_frequency.svg Sorry about the non-metric units! 5 inches = 12 cm 6inches = 15cm 7inches = 18cm
Rasputin had a reputation….. http://www.perpetualocean.com/tetherdcow/cowimage/rasputin1.jpg There is some doubt as to if the object in the jar was really his! http://img.dailymail.co.uk/i/pix/2007/11_02/rasputinBBC1711_468x556.jpg
Erection – if your interested… • The spongy tissue fills with blood, from arteries down the length of the penis. A little blood enters the corpus spongiosum; the remainder engorges the corpora cavernosa, which expand to hold 90% of the blood involved in an erection, increasing both in length and in diameter. The function of the corpus spongiosum is to prevent compression of the urethra during erection. • Blood can leave the erectile tissue only through a drainage system of veins around the outside wall of the corpus cavernosum. The expanding spongy tissue presses against a surrounding dense tissue (tunica albuginea) constricting these veins, preventing blood from leaving. The penis becomes rigid as a result. The glans penis, the expanded cap of the corpus spongiosum, remains more malleable during erection because its tunica albuginea is much thinner than elsewhere in the penis. • Take a look at this animation http://www.1on1health.com/web/info/erectilefunction/english/erectile-function-animation/AnimationPage/LookListenLearnType=1
The four E’s of SEEEEX • Excitement - • Erection – See the previous slide • Emission – What happens in the seminal vesicle. • Ejaculation - the "pressure chamber" theory, is outlined in The Science of Orgasm (2005) by Barry Komisaruk and colleagues. 1. Ducts fill with seminal fluid. 2. Fluid pressure builds up behind a closed sphincter valve, creating a "pressure chamber." 3. Sudden release of the valve causes fluid to shoot out of urethra. 4. Rinse and repeat. Kamisaruk, Barry, et al. The Science of Orgasm (2005).
Copulation • The sexual union of two individuals, resulting in insemination or deposition of the male gametes in proximity to the female gametes. • In humans “proximity” means with the penis inserted inside the vagina. • Do not confuse this with fertilization! http://www.answers.com/topic/copulation-1
http://www.health24.com/images/_content/male_female_intercourse.jpghttp://www.health24.com/images/_content/male_female_intercourse.jpg Be sure to notice that the Penis does not enter the Uterus!!! There are many more positions that a human can use
The Vagina • Is lined with mucus secreting cells to lubricate intercourse. • Is lined with erectile tissuue similar to the penis. It swells with arousal. • Is acidic. Why? • Some world cultures are fascinated with Hymens…… http://pics1.frozenbear.com/i/picfu1/2008/09/21/10/c/0/4/c04c4f8431796eba32d41d9792b55a200_main.jpg
The Cervix. • It is normally very small but the hole in the middle can expand to 10cm to let a baby out. • When not giving birth there is normally mucus blocking it. Why? • The mucus changes structure during the time of ovulation to allow sperm to get through. http://i.ehow.com/images/GlobalPhoto/Articles/4412548/cervix_Full.jpg
The uterus • Has a lining that is replenished every cycle called the Endometrium. • This gives a fresh new tissue “bed” for a fertilised egg to implant in. • Shedding the endometrium is Menstruation. http://www.thecancerblog.org/images/blogs/9-2007/uterus-436890.jpg
Fallopian tubes • There are 2 – one to each ovary. • They are lined with ciliated epithelium that create a current to waft the egg down towards the uterus. Why do eggs need this help and not sperm? • Fertilisation normally occurs here. http://www.fertility.com/Images/tube_fertilisation_tcm38-555.jpg
Ovaries • Make ova, • Make progesterone • Make oestrogen • There are 2 of them! • This picture shows the various stages of follicle/ova production – not all the stages happen at once! • Each ovary makes an ova every 56 days. • A woman is born with all the ova she will ever produce already in her ovaries but “frozen” at prophase of Meiosis 1. http://academic.kellogg.cc.mi.us/herbrandsonc/bio201_McKinley/f28-4a-d_ovary_c.jpg
The menstrual cycle • Why should a body willingly lose blood and tissue? It must be important for it to do so! - So that the Endometrium is at its freshest (with a very accessible blood supply) to accept a fertilised egg. http://www.maybe-baby.com/gallery/images/1144828120Cycle.jpg
What happens during menstruation? This can be split into 3 parts: 1.The hormones – Follicle stimulating hormone (FSH), Oestrogen, Lutenising Hormone (LH) and Progesterone, 2. What happens in the ovaries – The development of the Follicle, the development of the Corpus Luteum. 3. What happens in the uterus – the development and shedding of the endometrium.
Basically: • Pituitary gland releases FSH which travels in the blood to the ovary. • FSH causes the development of a follicle which in turn produces Oestrogen which travels in the blood to the uterus. • Oestrogen causes thickening of the endometrium.High oestrogen levels stimulate Pituitary gland to produce LH. • LH causes the scar from ovulation to become a corpus luteum. • Corpus luteum produces Progesterone with Prolongs the endometrium. • When the corpus luteum heals the drop off of progesterone allows the endometrium to disintigrate. • Drop off in progesterone also allows the pituitary to start making FSH again. http://www.soc.ucsb.edu/sexinfo/images/05-07-Menstrual.jpg
But what about the ethics? Think about: World overpopulation Playing God Who can afford it? What happens to unused embryos? Should single people be able to elect to be mothers? Why not adopt? How many orphans are there? Childless couples? http://www.firstivf.net/ivf_steps.jpg