KEY CONCEPT Germs cause many diseases in humans.

Germ theory states that microscopic particles cause certain diseases. Germ theory proposes that microorganisms cause diseases. proposed by Louis Pasteur led to rapid advances in understanding disease

Koch’s postulates support the theory. (DON”T COPY) Disease-causing agents are called pathogens. (COPY)

There are different types of pathogens. Bacteria are single-celled organisms. cause illness by destroying cells release toxic chemicals

Viruses are genetic material surrounded by a protein coat. force host cells to make more viruses very small

Fungi can be multicellular or single-celled. take nutrients from host cells occur in warm and damp places

Protozoa are single-celled organisms. use host cells to complete their life cycles take nutrients from host cell

Parasites are multicellular organisms. grow and feed on a host possibly kill the host

READ BUT DON’T COPY Different pathogen cause common infectious diseases.

Pathogens can enter the body in different ways. (READ BUT DON’T COPY) Pathogens can be transferred by direct or indirect contact. Indirect contact does not require touching an infected individual. touching an infected surface breathing in infected air

Vectors carry a pathogen and transmit it into healthy cells. READ BUT DON’T COPY Vectors carry a pathogen and transmit it into healthy cells. Direct contact requires touching an infected individual. Includes: kissing sexual intercourse hand shaking tick

31.2: Immune System KEY CONCEPT The immune systems consists of organs, cells, and molecules that fight infections.

Many body systems protect you from pathogens. 31.2: Immune System Many body systems protect you from pathogens. The immune system is the body system that fights off infection and pathogens. Many other tissues and systems help the immune system. Skin is a physical barrier to infection. Mucous membranes trap pathogens entering the body. The circulatory system transports immune cells.

Cells and proteins fight the body’s infections. 31.2: Immune System Cells and proteins fight the body’s infections. White blood cells attack infections inside the body. Phagocytes engulf and destroy pathogens. T cells destroy infected cells. B cells produce antibodies. READ BUT DON’T COPY

31.2: Immune System READ BUT DON’T COPY Immunity prevents a person from getting sick from a pathogen. In all immunity, pathogens are destroyed before you get sick. Passive immunity occurs without an immune response. mother’s milk genetics Active immunity occurs after a specific immune response

31.3: Immune Responses KEY CONCEPT The immune system has many responses to pathogens and foreign cells.

31.3: Immune Responses In fever, body temperature increases. Low fevers stimulate white blood cells to mature. High fevers can cause seizure, brain damage, and even death.

The immune system rejects foreign tissues. 31.3: Immune Responses (READ BUT DON’T COPY) The immune system rejects foreign tissues. Tissue rejection occurs in organ or tissue transplants. Tissue rejection is the result of an immune response. immune system detects protein markers on the donor tissue makes antibodies against the donor’s tissue (READ BUT DON’T COPY)

34.1: Reproductive Anatomy KEY CONCEPT Female and male reproductive organs fully develop during puberty.

The female reproductive system produces ova. 34.1: Reproductive Anatomy The female reproductive system produces ova. There are two main functions of the female reproductive system. produce ova, or egg cells provide a place where a zygote develops uterus cervix rectum vagina urethra urinary bladder pubic bone ovary fallopian tube

34.1: Reproductive Anatomy Estrogen has three main functions. develop female sexual characteristics develop eggs prepare uterus for pregnancy

The male reproductive system produces sperm. 34.1: Reproductive Anatomy The male reproductive system produces sperm. There are two main functions of the male reproductive system. produce sperm cells deliver sperm to the female reproductive system urinary bladder vas deferens pubic bone prostate gland penis urethra testis scrotum epididymis bulbourethral gland rectum seminal vesicle

34.1: Reproductive Anatomy Testosterone has two main functions. developing male sexual characteristics producing sperm

34.2: Reproductive Processes KEY CONCEPT Human reproductive processes depend on cycles of hormones.

Eggs mature and are released according to hormonal cycles. 34.2: Reproductive Processes Eggs mature and are released according to hormonal cycles. potential egg first polar body second polar ovum (egg) Meiosis I Completed Meiosis II only after sperm enters meiosis produces eggs and polar bodies each egg has 23 chromosomes meiosis is completed at fertilization

34.2: Reproductive Processes Hormones, including estrogen stimulate the release of eggs. Begins with ovulation (release of an egg from ovary) egg travels into fallopian tube, then to uterus fallopian tube egg cell egg released corpus luteum uterine wall ovary follicle uterus 5 to 7 days to uterus

Eggs mature and are released according to hormonal cycles. 34.2: Reproductive Processes READ BUT DON’T COPY Eggs mature and are released according to hormonal cycles. The menstrual cycle has three phases. 1. endometrium sheds 2. ovulation occurs 3. corpus luteum forms

34.2: Reproductive Processes The menstrual cycle stops at menopause. cycle continues until a woman’s mid-40’s or 50’s decline in hormone levels make cycles irregular eventually, cycle stops altogether

Sperm production in the testes is controlled by hormones. 34.2: Reproductive Processes Sperm production in the testes is controlled by hormones. Hormones stimulate sperm production. one sex cell divides into four sperm each sperm has 23 chromosomes potential sperm 4 sperm cells Meiosis I Meiosis II

Fertilization occurs when a sperm cell joins an egg cell. 34.2: Reproductive Processes Fertilization occurs when a sperm cell joins an egg cell. Sperm penetrates an egg. membrane keeps out other sperm nucleus of sperm joins with egg zygote formed

34.2: Reproductive Processes (READ BUT DON’T COPY) Multiple zygotes can result from fertilization. identical twins from the same egg fraternal twins from two separate eggs Infertility makes reproduction difficult or impossible.

Sexually transmitted diseases affect fertility and overall health. 34.2: Reproductive Processes (READ BUT DON’T COPY) Sexually transmitted diseases affect fertility and overall health. Sexually transmitted diseases (STDs) are passed from one person to another during sexual contact. bacterial STDs include chlamydia, syphilis, gonorrhea viral STDs include hepatitis B, genital herpes, human papillomavirus, and HIV HIV

34.2: Reproductive Processes (READ BUT DON’T COPY) Bacterial STDs can be treated, and in many cases, cured with antibiotics Viral STDs can be treated, but there is no cure for these diseases. STDs attack reproductive organs. can cause infertility untreated, some can be fatal A parasite causes trichomoniasis, which can affect fertility. STDs can be avoided by abstinence or by using a condom.

32.3 KEY CONCEPT Development progresses in stages from zygote to fetus.

The zygote becomes a blastocyst and implants in the uterus. The fertilized egg implants into the uterus and is nourished by the placenta and umbilical cord. The zygote becomes a blastocyst and implants in the uterus. READ BUT DON’T COPY ectoderm develops into skin and nervous system mesoderm develops into Internal tissues and organs endoderm develops into digestive organs and their lining blastocyst uterine wall Implantation of blastocyst

The blastocyst becomes an embryo. Embryonic membranes protect and nourish the embryo. amniotic sac cushions embryo. placenta connects mother and embryo. umbilical cord connects embryo to placenta. placenta umbilical cord uterus amniotic sac

A zygote develops into a fully formed fetus in about 38 weeks. Human pregnancies are divided into trimesters. 1st trimester: body plan and early development Leave a few lines for notes here

2nd trimester: fetus more active, developed Leave a few lines for notes here

3rd trimester: all organs fully formed Leave a few lines for notes here After about 38 weeks, fetus is ready to be born.

READ BUT DON’T COPY The mother affects the fetus, and pregnancy affects the mother. The fetus depends on the mother for all its nutrition. mother's diet must support fetal health mother must avoid toxic chemicals

READ BUT DON’T COPY The mother’s health is affected by pregnancy in a number of ways. increase in Calories and body weight pregnancy hormones affecting homeostasis regular medical checkups needed