Chapter 18 Reproduction and Heredity

The Endocrine System Endocrine glands- glands that produce and release chemicals Hormones- chemical substances produced by endocrine glands.

The Pituitary Gland small gland at the base of the brain Controls growth rate, metabolism, and reproduction Called the “master gland” because it regulates many other endocrine glands

Hypothalamus Controls the pituitary gland Regulates body temperature, use of water, and blood pressure Oversees many of the hormone levels in the body

Adrenal Glands Produce hormones that affect the functioning of your kidneys, your metabolism, and your response to stressful situations Adrenaline – hormone important in the fight or flight response

Thyroid Gland Releases a hormone that regulates metabolism Releases a hormone that regulates the amount of calcium in the blood

Parathyroid Gland 4 tiny glands attached to the back of the thyroid that regulates levels of calcium and phosphorus.

Pancreas Located behind the stomach Part of two systems – digestive and endocrine In the endocrine it controls the level of sugar in the blood. Improper function can cause: Diabetes—level of sugar too high or Hypoglycemia—level of sugar too low.

Thymus Function not thoroughly understood. Plays a role in developing some of the body’s defenses against infection.

Reproduction and the Endocrine System Ovaries – reproductive glands in females Testes – reproductive glands in males Follicle-stimulating hormone (FSH) Luteinizing hormone – Two hormones produced by the pituitary gland that begin that process of sexual maturation in adolescents

Reproduction and the Endocrine System In males, testosterone and FSH control production of sperm, the male sex cells. Testosterone is also responsible for developing and maintaining other male traits such as deepening voice and body hair In females, two female sex hormones, progesterone and estrogen are produced by the ovaries. They are responsible for developing other female traits such as breast development and widening of the hips In addition, progesterone and estrogen work with FSH and LH to produce ova or eggs.

Reproductive System terms Puberty – is the period of sexual development during which males and females become sexually mature and able to produce children. Fertilization – the joining of a sperm cell with an egg cell

The Male Reproductive System Testes- produce testosterone and sperm The testes hang outside the body within sac of skin called the scrotum Epididymis- a J-shaped tube located on the back of each testis Sperm mature and gain the ability to move while in the epididiymis. They are stored there for several weeks.

The Male Reproductive System Penis – external sex organ through which sperm leave the body. Glans – tip of the penis Circumcision – surgical procedure that removes the foreskin after birth

The Male Reproductive System Vas deferens- tube that receives sperm from the epididymis Urethra- tube that passes through the penis to the outside of the body

The Male Reproductive System Seminal Vesicle – a pair of glands located near the bladder Cowper’s glands – a pair of glands located at the base of the penis Prostate gland – near the bladder at the midline of the body Sperm mixes with fluids from these glands to form Semen

Sperm Production For most men sperm production continues throughout adult life unless the reproductive system is altered in some way About 400 million sperm are released during one ejaculation

Sperm Production Semen contains nutrients that enable the sperm to survive for several days inside the female body. Ejaculation- ejection of sperm from the penis Nocturnal emission – erection and ejaculation during sleep

“Flow Chart” of the male reproductive system Hypothalamus signals pituitary to release FSH& LH > stimulate cells of testes> produce testosterone> produce sperm in testes> moves them to epididymis> through Vas Deferens> through Seminal Vesicles, Prostate Gland, and Cowper’s Gland where other fluids are added to form semen> out through Urethra/Penis> out of body through process called ejaculation.

Disorders of the Male Reproductive System Sterility- condition in which a person is unable to reproduce Environmental factors, mumps, cancer, injury Undescended Testes- results when one testes does not descend into the scrotum at birth. Corrected with surgery or hormone treatment Inguinal hernia-occurs when part of the intestine pushes into the scrotum through a weak spot in the wall near the scrotum. Corrected with surgery

Disorders of the Male Reproductive System Enlarged Prostate- causes pain and discomfort Cancer of the Prostate or Testicle Cancer is an area of uncontrolled cell growth that invades the surrounding tissue and destroys it. Most effective when treated during the early stages.

Keeping the Reproductive System Healthy Cleanliness Protective equipment Avoid heavy lifting Any signs of pain during urination, unusual discharge, swelling in the genitals or sores on the genitals should require a medical examination Testicular self-examination

Female Reproductive System

Ovaries Small organ about the size of an almond They release estrogen and progesterone and they release mature egg cells Ovulation- the monthly process where the ovaries release one ripened egg

Fallopian Tubes Also called oviducts, are small tubes that carry the released egg from the ovaries. The fingerlike ends of the fallopian tube draw the egg into the opening. Tiny hairs in the oviducts sweep the egg through the sperm. The fallopian tubes are where eggs are usually fertilized.

Uterus A hollow pear-shaped organ located between the two ovaries and behind the bladder. This is where the fertilized egg develops and grow into a baby Cervix-the narrow base of the uterus

Vagina Or birth canal, is a hollow muscular passage leading from the uterus to the outside of the body.

The Menstrual Cycle The process during which an egg matures and is released and the uterus prepares to receive it.

The Menstrual Cycle Endometrium- lining of the uterus The endometrium thickens to prepare for a fertilized egg. When the egg is not fertilized the endometrium breaks down and is discharged from the body. This discharge of blood and tissue is know as menstruation

Stages of the Menstrual Cycle Every woman’s menstrual cycle is different. Premenstrual Syndrome (PMS)-discomfort experienced before the menstrual period. Menopause-hormone production slows and eggs are no longer released. Gradually menstruation stops, and the women is no longer fertile.

Disorders of the Female Reproductive System Endometriosis- condition where tissue from the lining of the uterus grows outside the uterus causing pain in the pelvic area. – Can lead to sterility – Can be corrected through hormone treatment or surgery Toxic Shock Syndrome- a rare disease caused by a bacterial infection – It is important to change tampons regularly to avoid infection – Symptoms include: sudden high fever, a rash, vomiting, diarrhea, and dizziness

Disorders of the Female Reproductive System Sterility- blocked fallopian tubes, failure of the ovaries to release eggs, and endometriosis Cysts and Cancer- Pap Test-medical procedure in which a sample of cells is taken from the cervix and examined under a microscope for signs of cancer.

Keeping the Reproductive System Healthy Cleanliness – Feminine Hygiene products are not necessary and in fact can sometimes be harmful Monthly breast self-examination Yearly gynecological exam for women who have reached puberty Mammogram- an x-ray of the breast that can detect cancer.

Heredity Heredity- the passing on, or transmission, of biological characteristics from parents to child. Chromosomes- tiny structures found within every cell that carry the information about the characteristics you will inherit. Deoxyribonucleic acid or DNA is the chemical substances that make up chromosomes Gene- a section of a chromosome that determines a single trait.

Heredity Dominant and Recessive Genes – Dominant genes are expressed whenever they are present – Recessive genes are expressed only when the dominant gene is not present Sex Determination – XX= femaleXY= male – All eggs have one X chromosome – Sperm cells have either an X or Y chromosome so the sperm cell determines the sex of the child

Genetic Disorders Genetic Disorder-an abnormal condition that a person inherits through genes or chromosomes Recessive Disorders – Sickle Cell disease A genetic blood disorder that occurs most often among african americans. The abnormal sickle shape of the red blood cells caused clumping and blocking of small blood vessels

Genetic Disorders Tay-Sachs Disease- characterized by the lack of an important chemical in the brain – Found primarily among people of Eastern Jewish descent. – No treatment Phenylketonuria or PKU- a rare metabolic disorder that can cause severe mental retardation in infants – Can be treated successfully if the infant follows a special diet

Genetic Disorders Cystic Fibrosis- a recessive disorder that occurs mainly among white people. – Mucus that lines the lungs becomes thick and sticky – Causes bacteria to stay in the lungs leading to infection and eventually lung damage

Sex-linked Disorders Sex-linked disorders- the gene for the disorder is found on a sex chromosome, usually the X chromosome Duchenne muscular dystrophy- a condition in which the person lacks a protein needed for muscle function – A person with the disease eventually loses muscle control

Sex-Linked Disorders Hemophilia- a person’s blood does not clot properly – Physical activity can lead to internal bleeding – Medications can help control hemophilia

Down Syndrome A disorder that is the result of an extra chromosome – The have a distinctive physical appearance and have mental impairments that can range from mild to severe