TOPIC+11+HUMAN+HEALTH+PHYSIOLOGY

// 11.4.1 Annotate a light micrograph of testis tissue to show the location of interstitial cells (Leydig cells), germinal epithelium cells, developing spermatozoa and Sertoli cells. //


 * Orange book **** à ** pg. 265
 * Green book **** à ** pg. 181

The production of sperm cells occurs within the testes. The testes of human males are located outside the body in order to provide the cooler temperature necessary for production of sperm cells or spermatozoa. Inside each testis, spermatogenesis occurs within very small tubes known as seminiferous tubules. Near the outer wall of the seminiferous tubules lie ** germinal epithelial cells ** called spermatogonia. Large ** Sertoli cells ** stretch from germinal epithelium to the lumen and are responsible for nourishing the sperm cells during differentiation. Interspersed between Sertoli cells are ** interstitial (Leydig) cells ** which produce testosterone.

// 11.4.2 Outline the processes involved in spermatogenesis within the testis, including mitosis, cell growth, the two divisions of meiosis and cell differentiation. //


 * Orange book **** à ** pg. 265
 * Green book **** à ** pg. 181-182

Watch the following animation “How Meiosis Works” [] This animation is an overview of meiosis – watch it before tackling spermatogenesis. View the animation: “Spermatogenesis” and then take the short quiz. []
 * To do: **

View the final animation: []

// 11.4.3 State the role of LH, testosterone and FSH in spermatogenesis. //

// 11.4.4 Annotate a diagram of the ovary to show the location and function of germinal epithelium, primary follicles, mature follicles and secondary oocytes //

// 11.4.5 Outline the processes involved in oogenesis within the ovary, including mitosis, cell growth, the two divisions of meiosis, the unequal division of cytoplasm and the degeneration of polar body. //


 * Orange book ** à pg. 266
 * Green book ** à pg. 182-183

Watch the following animation “Maturation of the Follicle and Oocyte” []
 * To do: **

View the animation: “Oogenesis” []

// 11.4.6 Draw and label a diagram of a mature sperm and egg. //


 * Orange book ** à pg. 267
 * Green book ** à pg. 183

View the animation again: “Maturation of the follicle and ooctye” []

The animation is good for reviewing egg and sperm structure as well as acrosome and cortical reactions (11.4.9). []

// 11.4.7 Outline the role of the epididymis, seminal vesicles and prostate gland in the production of semen. //


 * Orange book ** à pg. 267


 * Green book ** à pg. 183


 * To do: **

In your green books write one sentence to outline the role of the epididymus, seminal vesicles & prostate gland.

Sperm cells are formed in the seminiferous tubules and carried through the lumen until they reach the epididymis. Here, sperm cells are stored and gain motility. One sexual arousal, a large number (millions) of sperm cells move from the epididymis into the vas deferens. As the sperm cells move along the vas deferens near the area of the bladder, a pair of glands called the seminal vesicles add a large volume of fluid. This fluid has a high concentration of the sugar fructose, a high-energy carbohydrate needed to provide energy for the sperm cells to swim to the ovum. Approximately 70% of the fluid in semen is added by the seminal vesicles. Near this same area, the prostate gland adds more fluid to the semen. The fluid from the prostate is alkaline and helps the spermatozoa survive the environment within the female’s vagina. Approximately 30% of the semen is fluid from the prostate.

// 11.4.8 Compare the processes of spermatogenesis and oogenesis, including the number of gametes and the timing of the formation and release of gametes. //


 * Orange book ** à pg. 267


 * Green book ** à pg. 184


 * To do: **

View the animation: “Comparison of spermatogenesis and oogenesis”

[]

// 11.4.9 Describe the process of fertilization, including the acrosome reaction, penetration of the egg membrane by a sperm and the cortical reaction. //


 * Orange book ** à pg. 268


 * Green book ** à pg. 184


 * To do: **

The following website is good for reviewing egg and sperm structure as well as acrosome and cortical reactions.

[]

The following website is TOO detailed – only look out for terms you need to know: acrosome reaction and cortical reaction.

[]

// 11.4.10 Outline the role of HCG in early pregnancy. //


 * Orange book ** à pg. 270


 * Green book ** à pg. 185


 * To do: **

In your green books:


 * write a sentence or two to recap on the role of the corpus luteum and secretion of progesterone.
 * Write a sentence of two to summarise the role of HCG hormone.


 * Recap on Corpus Luteum and Hormones **

Ovulation of the secondary oocyte left an outer ring of follicle cells within the ovary. This remaining layer of follicle cells begins to mitotically divide and secrete the hormones oestrogen and **progesterone**. This hormone-secreting tissue has become a temporary endocrine gland called the **corpus luteum**. Each menstrual cycle in which there has not been a fertilization, the corpus luteum continues to secrete progesterone for about **14 days**. High levels of oestrogen and progesterone help maintain the thickened, highly vascular blood lining (endometrium) of the uterus. This highly vascular tissue is necessary in case there has been a fertilization and an embryo will be implanting itself into the endometrium. If no fertilization has occurred, the corpus luteum becomes the corpus albicans, stops hormone production and the endometrium begins to break down.


 * Human Chorionic Gonadotrophin (HCG) **

If fertilization has occurred, the embryo enters the uterus and begins **implanation** about a week after fertilization. This is well within the time period that the corpus luteum is still active. Soon after implantation, the embryo begins secreting a hormone of its own. This hormone is **human chorionic gonadotrophin (HCG).** HCG enters the bloodstream of the mother; its target is the corpus luteum; HCG acts to maintain the secretory functions of this gland beyond the length of time typical of a normal menstrual cycle. The corpus luteum continues to secrete both oestrogen and progesterone and the endometrium, in which the early embryo is embedded, is maintained. Later in pregnancy, the role of oestrogen and progesterone production is taken over by the placenta.