Chapter 34 Endocrine & Reproductive Systems

Raquel Remick & Serena Brouelette

Sections 34.1-34.2

Endocrine System

• The function of the endocrine system is to produce chemical messengers (hormones) from glands to regulate certain body activities.

• • • • • • • • • 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

Sections 34.3 & 34.4

Reproductive 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

• • • 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

• • • 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

• • 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

• • • 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

• • • 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

• • • • 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

4 Phases of Menstrual Cycle

• • • • Follicular Ovulation Luteal Menstruation

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 3 membranes rd 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

• • • 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

Later Stages of Development

• • • By 3 months, most of the baby’s major organs have formed.

During 2 nd 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 3 rd Trimester, the organ systems mature and the fetus doubles in size.

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