Human Reproduction

Morula = A solid ball of 16 cells formed by day three after fertilisation Blastocyst = A hollow ball of cells that begins to make connections with the uterus for implantation Embryo = The developing baby up to 8 weeks old Foetus = The developing baby from week 9 onwards

Endoderm = Forms the lining of the gut, the respiratory and the urinogenital system Mesoderm = Forms blood, bone and muscle Ectoderm = Forms the skin, epidermis and the nervous system

Low testosterone levels in males = Hormone replacement therapy with testosterone Fallopian tube blockage in females = Treatment of subclinical infections such as chlamydia Endocrine gland failure in females = Hormone replacement therapy (HRT)

<p>Umbilical cord = Carries foetal blood to the placenta Vein = Carries foetal blood back from the placenta to the foetus Mother's blood and foetal blood = Do not mix</p> Signup and view all the answers

<p>Sperm = The male gamete and can survive for up to five days Epididymis = A tubular structure on the outside of each testis which stores immature sperm until ejaculation Sperm duct (Vas deferens) = Sperm that leave the epididymis during ejaculation is passed along the sperm duct by peristalsis to the urethra Cowper’s Gland = Adds a thick and slippery fluid to the penis for lubrication during intercourse. Flushes the urethra before sperm arrives</p> Signup and view all the answers

<p>Ovaries = One ovary releases an egg every 28 days on average. The egg is the female gamete and survives for about two days Fallopian tubes = Lined with cilia with beat in unison to waft the egg towards the uterus. Fertilisation occurs in the top third of the fallopian tube Uterus = A muscular sac which holds and nourishes the developing embryo Endometrium = The innermost lining of the uterus and is the site of implantation and placenta formation. Thickens in preparation for the arrival of a fertilised egg</p> Signup and view all the answers

<p>Seminal Vesicles = Add sugar solution to sperm in the sperm duct to feed them on their journey to the fallopian tube to fertilise the egg. Seminal fluid makes up 60% of sperm Semen = A milky white sticky liquid of sperm and fluids from the seminal vesicles, the prostate gland, and the Cowper’s gland Prostate Gland = Produces a thin, milky fluid that forms part of the semen Cowper’s Gland = Adds a thick and slippery fluid to the penis for lubrication during intercourse. Flushes the urethra before sperm arrives</p> Signup and view all the answers

<p>Head = Contains the haploid nucleus consisting of one set of chromosomes Midpiece = Contains mitochondria which supply the energy necessary to complete the journey from the vagina to the top of the fallopian tube Tail = Spins and produces the force necessary to propel the sperm and make them motile Acrosome = A bag of digestive chemicals that helps penetrate the egg</p> Signup and view all the answers

<p>Oestrogen = Enlargement of the breasts, widening of the hips, development of pubic and underarm hair and thickening of the layer of subcutaneous fat giving a more rounded figure Progesterone = Keeps the endometrium built up and stops the uterus from contracting FSH and LH = Cause the follicle to swell and burst, releasing the egg hCG = Maintains the endometrium if pregnancy occurs</p> Signup and view all the answers

<p>Menstruation = Occurs on day one of the cycle and lasts for four or five days Fertile period = Days 9 to 15, when fertilisation is possible Ovulation = Occurs on day 14, when the egg is released from the ovary Corpus luteum stage = Days 15 to 21, when the empty follicle transforms into a corpus luteum and secretes progesterone</p> Signup and view all the answers

<p>Cervix = Neck of the womb, blocked by a mucus plug for most of the month. Around the time of ovulation, the mucus thins out to allow sperm to swim through and enter the uterus Vagina = During copulation, it stimulates the penis to ejaculate and ensures sperm is deposited against the cervix. Lubricated with acidic mucus to prevent the growth of pathogenic microorganisms Vulva = Outer lips of the vagina Graafian follicle = After meiosis, a haploid egg is surrounded by this, which produces oestrogen</p> Signup and view all the answers

<p>Oestrogen = Repairs and thickens the endometrium, Tells the anterior pituitary gland to stop producing FSH Luteinising hormone (LH) = Tells the anterior pituitary to start producing it, Causes the final maturation of the Graafian follicle and ovulation Progesterone = Inhibits both FSH and LH, Thickens the endometrium Human chorionic gonadotropin (hCG) = If pregnancy occurs, it is produced by the placenta and maintains the corpus luteum and thus the production of progesterone</p> Signup and view all the answers

<p>Ovulation = The release of an egg from an ovary on day 14 of the cycle Fertilisation = The fusion of the haploid male and female gamete nuclei to form a diploid zygote In vitro fertilisation (IVF) = The fertilisation of eggs outside the womb, usually in a petri dish Copulation = The natural process of using the erect penis to deposit semen at the top of the vagina beside the cervix</p> Signup and view all the answers

<p>Corpus luteum = The remains of the Graafian follicle after ovulation, produces progesterone Graafian follicle = Develops from a primary oocyte under the influence of FSH, produces oestrogen Infertility = If a couple cannot conceive a child after a year of trying Menstrual Disorders = Benign growths in the wall of the uterus which can range in size, caused by some cells having more oestrogen and progesterone receptors than others</p> Signup and view all the answers

<p>Positive feedback = A process in which the production of one substance causes an increase in production of another Negative feedback = A process in which the production of one substance stops the other substance from being produced Artificial insemination = If sperm is collected from a donor and placed into the vagina or the uterus using a medical implement Menstrual Cycle = The process involving the development and release of an egg, and the preparation of the uterus for pregnancy</p> Signup and view all the answers

<p>Abstinence = Avoiding sexual intercourse prevents pregnancy and STIs Condoms = Form a latex barrier between the sperm and the egg. They give protection against STIs once they are put on before any sexual contact. 99% reliable if used properly Contraceptive pill = Contains progesterone and oestrogen which prevent ovulation. 99% effective if correctly taken every day Vasectomy = Involves cutting a man’s sperm ducts and tying off the cut ends. 100% effective but difficult to reverse</p> Signup and view all the answers

<p>Cervical dilation = The cervix dilates, and the mucus plug breaks free and passes out of the vagina as a sticky, jelly-like pink mucus Delivery = The contractions of the uterine muscle become stronger causing the baby to move slowly through the pelvis. The mother must push as the baby’s head descends through the birth canal, then one shoulder followed by the other, then the rest of the baby slides out Placental delivery = The placenta and the rest of the umbilical cord (afterbirth) pass out of the body through the birth canal Milk Production and Breastfeeding = Suckling the baby stimulates the anterior pituitary to produce two hormones, prolactin and oxytocin</p> Signup and view all the answers

<p>Gaseous exchange = Oxygen diffuses from the mother’s blood into the baby’s blood, while Carbon dioxide diffuses from the baby’s blood to the mother’s blood Antibodies = Can be passed from the mother to the baby to give passive acquired immunity Nutrition = Glucose, amino acids, fats, vitamins, and minerals pass from the mother to the baby Endocrine gland = Makes progesterone and hCG to maintain the pregnancy and diffuses into the bloodstream</p> Signup and view all the answers

<p>Colostrum = Milk produced at the start of lactation, which is yellow in colour and rich in nutrients and antibodies Sterile at room temperature = Breast milk is safe to consume without any additional heating or sterilization Contains antibodies = Breast milk protects against many diseases and allergies Allows bonding of mother and baby = Breastfeeding creates a special bond between the mother and baby</p> Signup and view all the answers