Chapter 34 Endocrine & Reproductive Systems

1. Chapter 34 Endocrine & Reproductive Systems Raquel Remick & Serena Brouelette

2. Sections 34.1-34.2Endocrine System • The function of the endocrine system is to produce chemical messengers (hormones) from glands to regulate certain body activities.

3. Roles of endocrine glands: • Pituitary: controls other glands • Pineal: regulates sleep and wake cycles, along with other basic functions • Hypothalamus: controls secretions of the pituitary gland • Thyroid: regulates metabolism • Parathyroid: maintains homeostasis in blood calcium levels • Adrenals: helps body prepare for and deal with stress • Pancreas: releases insulin and glucagon to regulate level of glucose in blood • Ovaries (female): produces eggs and estrogen to create female characteristics • Testes (male): produces sperm and testosterone to create male characteristics

4. Sections 34.3 & 34.4Reproductive System Structures of the male reproductive system: • Testes: primary male reproductive organ; produces sperm and releases hormone testosterone • Scrotum: sac that houses the testes; it can raise or lowers to adjust the temperature so that it is optimal for sperm development • Epididymis: comma shaped structure found on outside of testes; sperm travel here from testes to mature

5. Vas deferens: tube leading to the epididymus to urethra; stores sperm until they are released from the body • Seminal vesicles: first gland that sperm pass on their way out of the body; secretes a liquid containing fructose to nourish sperm and give them energy needed to swim • Prostate gland: next gland; secretes an alkaline substance that makes up most of the seminal fluid; this fluid protects sperm from acid in male urethra and increases motility

6. Bulbourethral gland: last gland; small and closest to urethra; secretes an alkaline substance often secreted before ejaculation to prepare urethra for sperm • Urethra: passageway leading from bladder to exterior of body; common outlet for semen and urine • Penis: organ through which urine or semen must pass to exit the body; organ by which semen is introduced to female vagina

7. Glans penis: enlarged end of penis; the head • Ejaculation: when male is sexually aroused, autonomic nervous system prepares male organs to deliver sperm; smooth muscles lining glands of reproductive tract contract and eject sperm from male body; If sperm are released into reproductive tract of female, chances of one sperm finding an egg are quite good

9. Structures of the female reproductive system: • Ovaries: primary female reproductive organs; produce eggs and release estrogen • Fimbrae: fingerlike projections that accept the egg from the ovary to to the Fallopian tube • Fallopian tubes: tube that carries mature egg from ovary to uterus; place where fertilization ocurs

10. Uterus: hollow muscular cavity that receives the fertilized egg and where the fetus develops; where the egg disintegrates if not fertilized • Cervix: lower portion of uterus; opening that leads to the vagina • Vagina: passageway that leads from uterus to outside body; where babies pass through to be born and male’s penis is introduced

11. Vulva: collective term for the external reproductive organs of the female • Clitoris: small organ made of erect tissue; homologous to the head of the penis • Endometrium: the lining of uterus; each month it becomes thick to prepare for fertilization; sloughed off if no fertilizations • Ovulation: process of releasing an egg from the ovary

12. 4 Phases of Menstrual Cycle • Follicular • Ovulation • Luteal • Menstruation

13. Zygote’s Early Development • Initially the zygote is a single cell just the size of a dot • At four days, embryo is about 64 cells • 6-7 days after fertilization, embryo implants into uterine wall • Placenta forms by 3rd week. It is the organ through which mother and child exchange gases and nutrients; the blood of the mother and infant do not actually mix, but flow past each other and gases and nutrients diffuse across thin membranes

14. The amniotic sac also develops, which is a fluid filled sac that protects the baby within the uterus. • After 4 weeks, the heart starts beating • After 6 weeks, limb buds appear

15. Later Stages of Development • By 3 months, most of the baby’s major organs have formed. • During 2nd trimester, the mother starts to visibly look pregnant, the fetal heartbeat can be heard from a stethoscope, and mother can feel fetus move • In the 3rd Trimester, the organ systems mature and the fetus doubles in size.

16. Childbirth • After 9 months, the child is fully developed and ready to be born. • Oxytocin is released, which causes contractions of the uterine walls. • Cervix opens • Amniotic sac breaks • The after-birth follows: the placenta, amniotic sac, and umbilical cord still attached