Topic 6.6: Human health and physiology
93. Homeostasis involves maintaining the internal environment between limits, maintenance of a steady state. The nervous system and the endocrine system are both involved in the process of homeostasis.
94. The endocrine system consists of glands which release hormones that are transported by the blood.
95. The following must be maintained by homeostasis: blood pH, carbon dioxide concentration, blood glucose concentration, body temperature, and water balance.
96. Homeostasis involves monitoring levels of the above and correcting changes in their levels by negative feedback mechanisms.
97. Feedback systems involve the level of a product to control the rate of its own production.
98. In negative feedback systems a change in a level causes an opposite change.
Examples would include a rise in body temperature would trigger the system to lower the temperature. Another example is a decrease in blood glucose levels would trigger the system to raise glucose levels.
100. Control of blood glucose
High glucose levels
Beta cells in pancreas secrete insulin
Low glucose levels
Alpha cells in pancreas secrete glucagon
Insulin stimulates liver and muscle cells to absorb glucose
Glucose is not released by the liver
Glucose is not absorbed
Glucagon stimulates liver cells to break glycogen down into glucose and release the glucose into the blood
Lowers blood glucose levels Raises blood glucose levels
101. Diabetes mellitis is a medical condition in which there are problems with the body controlling blood glucose levels. There are recognized two forms of this condition:
Type I diabetes Type II diabetes
Onset is usually during childhood Onset is usually after childhood
Beta cells produce insufficient insulin
Insulin injections are used to control
Target cells become insensitive to insulin
Insulin injections are not usually needed glucose levels
Diet cannot by itself control the condition Low carbohydrate diets may control the condition

Reproduction
102. In the female reproductive system, be able to produce a drawing and label the following parts: ovary, oviduct (fallopian tubes), uterus, urinary bladder, urethra, cervix, vagina, and vulva.
103. In the male reproductive system, be able to produce a drawing and label the following parts: urinary bladder, seminal vesicle, prostate gland, vas deferens, epididymus, testis, scrotum, and penis.
104. During reproduction a sperm (male gamete) from the testes unites with an ovum
(female gamete) from the ovaries to produce a zygote which develops into an embryo.
105. Over time the embryo develops into a fetus before the birth of a baby occurs.
106. Functions of the male sex hormone testosterone: a. causes male genitalia, including a penis, to develop in the fetus b. increased testosterone during puberty causes pubic hair, an enlarged penis, and growth of skeletal muscles c. during adulthood it maintains the sex drive d. stimulates sperm production in the male
107. Female sex hormones include FSH, LH, estrogen, and progesterone.
108. FSH and LH are produced in the pituitary gland under control of the hypothalamus.
109. Estrogen and progesterone are produced by the ovaries.
110. The major function of FSH is to stimulate the development of follicles (fluid filled sacs that contain an egg cell) in the ovary.
111. LH stimulates follicles to become mature. Once mature the follicles release their egg (ovulation) into the oviducts (fallopian tubes).
112. After the matured follicle releases its egg it is called a corpus luteum.
113. Estrogen and progesterone stimulate the development of female secondary sex characteristics at puberty. They also stimulate the development of the uterus lining so that it may support the embryo if fertilization occurs.
114. The hypothalamus controls FSH and LH release from the pituitary through GnRH
(gonadotrophin releasing hormone).
115. The menstrual cycle of the female occurs between puberty and menopause. This cycle is controlled by the four female sex hormones listed above.
116. Key points about the menstrual cycle: a. the average length is 28 days b. ovulation occurs midway through the cycle (day 14) c. menstruation, the release of the uterine wall, occurs during the first 3-5 days of the menstrual cycle d. after ovulation the corpus luteum secretes large amounts of progesterone that causes the uterine lining to prepare for an embryo e. a spike in LH at day 14 causes ovulation f. FSH rises and causes follicle development in the early part of the cycle g. LH causes the follicle cells to secrete less estrogen and more progesterone h. after ovulation LH causes the follicle to develop into the corpus luteum i. estrogen stimulates development of the uterine lining during the first 14 days of the cycle j. if a pregnancy does not occur, the levels of estrogen and progesterone fall and this allows the release of FSH and LH

117. The lining of the uterus is called the endometrium.
118. The first day of menstruation is used to designate the first day of the menstrual cycle.
119. If intercourse occurs during the mid part of the menstrual cycle a pregnancy may occur as at this time egg and sperm would be close together.
120. When pregnancy does not occur during this time, infertility is said to occur.
Infertility may be temporary or permanent.
121. About 1 in 6 couples have temporary or permanent infertility.
122. IVF (in vitro fertilization) is one way infertile couples may be helped.
123. Process of IVF: a. a drug is injected each day for 3 weeks to stop the woman’s menstrual cycle b. large doses of FSH are injected each day for 10-12 days to stimulate follicle development c. HCG (human chorionic gonadotropin – pregnancy hormone) is injected 36 hours before egg collection to loosen the egg in the follicles and to cause their maturation d. sperm from the man is processed to increased to allow concentration of healthy gametes e. eggs are extracted from the ovaries via a tube inserted through the vagina wall f. each egg is mixed with sperm in a dish and they are placed in an incubator overnight g. dishes are checked for fertilization h. two or more embryos are selected and placed into the uterus by a long tube i. a pregnancy test is done (check for HCG) to see if any embryos implanted in the uterine wall j. pregnancy is closely monitored
5. Draw and label a diagram of the female reproductive system. Include the following: bladder, urethra, ovary, oviduct, uterus, cervix, vagina, and vulva.

6. Draw and label a diagram of the male reproductive system. Include the following: bladder, urethra, penis, testis, scrotum, vas deferens, epididymus, prostate gland, and seminal vesicle.