The Endocrine System & The Reproductive System Ms. Edwards

The Endocrine System Produces chemicals that control many of the body’s daily activities. Regulates long-term changes like growth and development. Made up of glands that do not connect to tubes Endocrine glands- produce and release chemicals directly into the blood stream.

Hormones Hormones- chemical messengers that are made by endocrine glands. Hormones direct the activities of different tissues and organs. Carried throughout the body in the bloodstream. Can act rapidly or be long-lasting Target cells- cells that recognize a hormone’s chemical structure.

Glands of the Endocrine System

Glands of the Endocrine System

Functions of Endocrine Glands Endocrine glands: hypothalamus, pituitary, thyroid, parathyroid, adrenal, thymus, pancreas. Hypothalamus Tiny part of the brain that links the nervous and endocrine systems. Controls sleep, hunger, and other basic body processes. Maintains homeostasis by sending nerve impulses and hormones.

Pituitary Gland Below hypothalamus, about the size of a pea Communicates with hypothalamus to control many body activities. Also releases hormones that turn other endocrine glands “off” and “on.” Pituitary hormones control growth and water uptake in kidneys.

The Endocrine System

Negative Feedback Type of regulation where the system is turned off by the condition it produces. Endocrine system uses negative feedback to maintain homeostasis. Through negative feedback, when the amount of a hormone reaches a certain level, the endocrine system tells the body to stop the release of that hormone. Similar to the thermostat in your house.

Negative Feedback The Endocrine System

Sexual Reproduction Ovaries and Testes control many bodily changes as a child matures. Egg- female sex cell Sperm- male sex cell Fertilization- joining of sperm and egg Zygote- fertilized egg

Sexual Reproduction Sex cells contain chromosomes, which contain DNA Every cell in the body that has a nucleus has 46 chromosomes. Sex cells have half the number of chromosomes, 23. During fertilization, egg (23 chrom.) + sperm (23 chrom). = zygote (46 chrom.)

Male Reproductive System Functions: to produce sperm and the hormone testosterone. Testes- organs where sperm are produced. Testosterone- hormone that controls the development of physical traits of men. Scrotum- external pouch of skin that houses the testes. Keeps the testes (and the sperm) 2-3 degrees cooler than the body.

Sperm Production Begins in males during the teenage years. Composed of a head (contains DNA) and tail (allows for movement). Semen- mixture of sperm cells and fluids. One drop has 5-10 million sperm! Urethra- tube through which semen exits the body. Penis- male sexual organ

The Male and Female Reproductive Systems

Female Reproductive System Functions: produce eggs, nourish baby until birth. Ovaries- female reproductive organs. Estrogen- hormone that controls development of female traits. Fallopian tubes- also called oviducts, passageways for eggs from ovaries to uterus. Fertilization usually happens here.

Female Reproductive System Uterus- hollow, muscular organ about the size of a pear. Fertilized egg implants and grows in the uterus. Vagina- muscular passageway leading to the outside of the body. Also the passageway through which a baby leaves the mother’s body.

The Male and Female Reproductive Systems

Menstrual Cycle The monthly cycle of changes that occur in the female reproductive system. Starts during female’s teenage years. Ovaries contain about 400,000 undeveloped eggs, but only about 500 will leave the body. During the menstrual cycle, an egg develops in an ovary and the uterus prepares for the arrival of an embryo.

Menstrual Cycle Egg starts to mature in ovaries, lining of uterus thickens Ovulation- the process of an egg leaving the ovaries. Egg can only be fertilized during ovulation. If egg is not fertilized, it breaks down and is shed, along with the lining of the uterus, from the body during menstruation. Menstruation lasts about 6 days, at the same time a new egg is maturing in the ovaries.

The Male and Female Reproductive Systems Menstrual Cycle

Human Life Cycle Before birth zygote  embryo  fetus zygote is no larger than a period. embryo- until 8th week of development fetus- 9th week until birth Amniotic sac- fluid-filled, protects baby Placenta- link between mother and baby. Oxygen, nutrients, and wastes are exchanged here. Umbilical cord- between fetus and placenta, another link between mother and baby.

4 wks- heart beat, eyes, ears 24 wks- fingerprints, complete eye Zygote 2 days 24 wks- fingerprints, complete eye 8 wks- heart chambers

The Human Life Cycle

Birth 3 stages: labor, delivery, afterbirth Labor- muscular contractions of uterus cervix dilates may last 2 to 20 hours Delivery- baby is pushed out of mother’s body baby is connected to placenta by umbilical cord Afterbirth- 15 minutes after delivery placenta is pushed out of body

The Human Life Cycle

Growth and Development Changes take place between infancy and adulthood include physical, mental, and emotional changes. Infancy First 2 years of life Large head, small body, rapid growth Gain coordination, begin to walk Begin to speak, follow directions, and play

Childhood Adolescence Ages 2 to about 12 Increase mental abilities, language skills Adolescence Stage when children physically and mentally become adults. Somewhere between ages 12-18. Puberty- period of sexual development

Adulthood Ages 18 to death Aging- begins about at 30. Skin wrinkles, eyesight weakens Aging becomes most noticeable around ages 40-65. Menstruation stops, sperm count lowers.