Biology Unit III - Reproductive System

Unit III - Living Things and Their Environment

• This unit covers living things and their environment.

Coordinated Functions of the Reproductive, Endocrine, and Nervous Systems

• Diagrams of the body's major organs are shown.

Reproductive System

• The male and female reproductive systems are shown.

Male Reproductive System

• The male reproductive system is a network of external and internal organs. They function to produce, support, transport, and deliver viable sperm.

Parts of the Male Reproductive System

• Penis: The primary organ for sexual intercourse and urination. It has three parts: the root, the body (shaft), and the glans (tip).
• Scrotum: A fibromuscular sac that houses the testes and maintains optimal temperature for sperm production through thermoregulation.
• Testes: Oval-shaped glands located within the scrotum. Responsible for producing sperm through spermatogenesis in the seminiferous tubules.
• Seminiferous tubules: Large, coiled tubes that are the chief site for sperm production.
• Epididymis: A coiled tube attached to each testicle where sperm mature and are stored until ejaculation.
• Ductus (Vas) deferens: A muscular tube that transports mature sperm from the epididymis to the ejaculatory ducts during ejaculation.
• Seminal vesicles: Produce a fructose-rich fluid that nourishes sperm and contributes to semen volume.
• Prostate gland: Adds enzymes and citric acid to semen, maintaining its fluidity and supporting sperm viability.
• Bulbourethral (Cowper's) glands: Secretions lubricate the urethra and neutralize residual acidity from urine.

Parts of the Male Reproductive System (cont.)

• Diagrams providing details of the male reproductive system's parts and their functions.

Male Hormones and Functions

• Luteinizing hormones (LH): Secreted by the anterior pituitary gland. Stimulates testosterone production (a sex hormone).
• Follicle-stimulating hormone (FSH): Also secreted by the anterior pituitary gland. Stimulates sperm production in the seminiferous tubules.
• Testosterone: Produced by Leydig cells. Responsible for secondary male characteristics (deepening voice, facial hair, broadening of shoulders, and increase in muscle mass) during puberty

Female Reproductive System

• This system includes parts of the female body involved in fertility, reproduction, and sex.

Parts of the Female Reproductive System

• Ovaries: Two ovaries, one on each side of the uterus. Produce female hormones (estrogen and progesterone), store eggs to mature.
• Fallopian tubes: Two thin tubes connecting the ovaries to the uterus. Allow the egg to travel to the uterus.
• Uterus: A hollow, pear-shaped organ that holds a fetus during pregnancy. The lining thickens with blood and other substances every month.
• Cervix: The lower part of the uterus that connects the uterus to the vagina. Prevents foreign materials from entering the uterus.
• Vagina: A muscular tube connecting the cervix to the outside of the body.
• Vulva: Collective name for the external parts of the female reproductive system. Includes the labia majora, labia minora, vaginal opening, and clitoris.

Parts of the Female Reproductive System (cont.)

• Detailed descriptions and diagrams of female reproductive system structures.

The Onset of Mature Egg Cell Production in Females

• Mature egg cell production starts around ages 11-14.
• Menarche refers to the first discharge of blood from the vagina.
• A normal adult female releases a mature egg cell from one of her ovaries each month.
• Gestation/Pregnancy refers to the nourishment and protection of a fertilized egg for nine months.

Egg Production

• Females are born with approximately 2,000,000 eggs, but only 400,000 will reach puberty.
• Hormonal changes during puberty enable one immature egg to complete development each month.
• In a female's lifetime, only 300-500 egg cells reach maturity.
• Ova (singular: ovum) is the term for mature egg cells released by the ovaries every month

The Ovarian Cycle

• A series of changes in the ovaries. Prepares for ovulation and egg release.
• The ovarian cycle spans about 28 days, but varies among females.
• Ovulation is the monthly release of an ovum from an ovary.
• The ovarian cycle occurs in two phases: follicular and luteal.

The Follicular Phase

• During this phase, hormones regulate the completion of egg maturation.
• The anterior pituitary gland releases hormones (FSH and LH) into the bloodstream, triggering follicle growth and estrogen production.
• Estrogen aids in ovarian follicle growth.
• Ovulation occurs when the follicle bursts.

Egg Cell Maturation

• Egg cells mature within follicles inside the ovary.
• A follicle is a cluster of cells surrounding an immature egg cell.

The Luteal Phase

• After ovulation, the luteal phase begins.
• Luteinizing hormones stimulate the ruptured follicle to form the corpus luteum.
• The corpus luteum secretes estrogen and progesterone.
• Progesterone signals the body to prepare for fertilization.

The Menstrual Cycle

• The menstrual cycle describes the sequence of events in the body as it prepares for pregnancy monthly.
• The cycle is controlled by changing levels of estrogen and progesterone during the ovarian cycle.
• The menstrual cycle begins on the first day of menstruation and ends on the first day of the next menstrual period.
• A typical cycle lasts about 28 days, although it varies slightly among individuals.

The Menstrual Cycle (cont.)

• Before and after ovulation, estrogen and progesterone increase, thickening the uterus lining.
• If pregnancy does not occur, progesterone levels decrease, causing the uterine lining to shed or menstruate.
• Menstruation is the monthly shedding of the uterine lining, a mixture of blood and discarded tissues leave the body.

Diagrams and Charts:

• Diagrams and charts show the different stages of the reproductive cycle, including hormone levels and menstrual phases.

Sexually Transmitted Diseases (STDs)

• Covers prevention, detection, and treatment of STDs.

Gonorrhea

• Caused by the bacterium Neisseria gonorrhoeae.
• Bacteria invade the epithelial lining of the vagina and the male urethra causing a pus-like discharge.
• Can affect the rectum, eyes, throat, and joints.
• Can affect babies born to infected mothers.

Syphilis

• Caused by the bacterium Treponema pallidum.
• Symptoms and stages: chancre, fever, skin rash.
• Untreated syphilis can lead to complications, including neurological damage.
• Congenital syphilis can occur if an infected mother passes it on to her baby.
• Antibiotics are used to treat early-stage syphilis.

Genital Herpes

• Caused by the herpes simplex virus type 2 (HSV-2).
• Characterized by painful and itching blisters in the genital area.
• Sores typically heal in about two weeks, but outbreaks could recur.
• Antiviral medications help manage outbreaks.

AIDS

• Acquired Immunodeficiency Syndrome (AIDS) is caused by Human Immunodeficiency Virus (HIV).
• HIV attacks the body's immune system.
• Symptoms may not appear for 5-10 years after infection.
• AIDS related symptoms might include weight loss, swollen lymph nodes, chronic fever, fatigue, and night sweats.
• AIDS can lead to opportunistic infections in the later stages of the disease.
• There is no cure for AIDS, though treatment can help delay the onset of complications.
• AIDS is transmitted through contact with body fluids like semen, vaginal fluids, blood, and breast milk.

Endrocrine System

• The endocrine system consists of glands that produce hormones controlling body functions.
• Examples include reproduction, metabolism, growth, and responses.

Glands of the Endocrine System

• Hypothalamus: Connects brain to the hormonal system and regulates the pituitary gland.
• Pituitary gland: The "master gland" controlling other endocrine glands such as thyroid, adrenal, ovaries, and testes. It releases hormones created by the hypothalamus.
• Thyroid gland: Located in the neck. Influences metabolism, energy levels, body temperature, and calcium levels.
• Parathyroid glands: Small glands in the neck that regulate calcium levels in the blood.
• Adrenal glands: Located atop the kidneys, influence body stress response, blood pressure control, and metabolism.
• Pineal gland: Located in the brain, influencing the body's circadian rhythm.
• Pancreas: Located behind the stomach and under the liver, regulating blood sugar levels.
• Gonads: Include ovaries (in women) and testes (in men). Produce hormones affecting reproduction and other body functions.

Hormones

• Hormones are chemical messengers. They're released by the endocrine system to coordinate the body's functions like development, reproduction, storing and using energy, and regulating internal processes.

Hormone Regulation

• The body produces more than 40 types of hormones.
• Feedback mechanisms regulate the amount of hormones by monitoring chemical amounts in the blood. Positive feedback increases production, and negative feedback brings amounts to normal levels.