Transcript 31.1 Pathogens and Human Illness

31.1 Pathogens and Human Illness
KEY CONCEPT
Germs cause many diseases in humans.
31.1 Pathogens and Human Illness
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
31.1 Pathogens and Human Illness
• Koch’s postulates support the theory. (DON”T COPY)
• Disease-causing agents are called pathogens. (COPY)
31.1 Pathogens and Human Illness
There are different types of pathogens.
• Bacteria are single-celled
organisms.
– cause illness by
destroying cells
– release toxic chemicals
31.1 Pathogens and Human Illness
• Viruses are genetic
material surrounded by
a protein coat.
– force host cells to
make more viruses
– very small
31.1 Pathogens and Human Illness
• Fungi can be multicellular or single-celled.
– take nutrients from host cells
– occur in warm and damp places
31.1 Pathogens and Human Illness
• Protozoa are single-celled organisms.
– use host cells to complete their life cycles
– take nutrients from host cell
31.1 Pathogens and Human Illness
• Parasites are multicellular organisms.
– grow and feed on a host
– possibly kill the host
31.1 Pathogens and Human Illness
• READ BUT DON’T COPY
• Different pathogen cause common infectious diseases.
31.1 Pathogens and Human Illness
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
31.1 Pathogens and Human Illness
• 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
31.1 Pathogens and Human Illness
31.2: Immune System
KEY CONCEPT
The immune systems consists of organs, cells, and
molecules that fight infections.
31.1 Pathogens and Human Illness
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.
31.1 Pathogens and Human Illness
31.2: Immune System
Cells and proteins fight the body’s infections.
• White blood cells attack infections inside the body.
READ
– Phagocytes engulf and destroy pathogens.
BUT
– T cells destroy infected cells.
DON’T
COPY – B cells produce antibodies.
31.1 Pathogens and Human Illness
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
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31.3: Immune Responses
KEY CONCEPT
The immune system has many responses to
pathogens and foreign cells.
31.1 Pathogens and Human Illness
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.
31.1 Pathogens and Human Illness
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
(READ
tissue
BUT
DON’T – makes antibodies against the donor’s tissue
COPY)
31.1 Pathogens and Human Illness
34.1: Reproductive Anatomy
KEY CONCEPT
Female and male reproductive organs fully develop
during puberty.
31.1 Pathogens and Human Illness
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
fallopian
tube
uterus
ovary
cervix
pubic bone
urinary bladder
urethra
rectum
vagina
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34.1: Reproductive Anatomy
• Estrogen has three main functions.
– develop female sexual characteristics
– develop eggs
– prepare uterus for pregnancy
31.1 Pathogens and Human Illness
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
seminal vesicle
vas deferens
pubic bone
prostate gland
rectum
penis
urethra
epididymis
scrotum
testis
bulbourethral
gland
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34.1: Reproductive Anatomy
• Testosterone has two main functions.
– developing male sexual characteristics
– producing sperm
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34.2: Reproductive Processes
KEY CONCEPT
Human reproductive processes depend on cycles of
hormones.
31.1 Pathogens and Human Illness
34.2: Reproductive Processes
Eggs mature and are released according to hormonal
cycles.
potential
egg
– meiosis produces eggs and
polar bodies
– each egg has 23
chromosomes
– meiosis is completed at
fertilization
Meiosis I
Completed
first polar
body
Meiosis II
Completed
only after
sperm
enters
second polar
body
ovum (egg)
31.1 Pathogens and Human Illness
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
uterus
5 to 7 days to uterus
follicle
egg cell
egg released
ovary
uterine wall
corpus luteum
31.1 Pathogens and Human Illness
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
31.1 Pathogens and Human Illness
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
31.1 Pathogens and Human Illness
34.2: Reproductive Processes
Sperm production in the testes is controlled by
hormones.
• Hormones stimulate sperm
potential
production.
sperm
– one sex cell divides into
four sperm
– each sperm has 23
chromosomes
Meiosis I
Meiosis II
4 sperm cells
31.1 Pathogens and Human Illness
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
31.1 Pathogens and Human Illness
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.
31.1 Pathogens and Human Illness
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
31.1 Pathogens and Human Illness
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
• STDs can be avoided by
can affect fertility.
abstinence or by using a
condom.
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32.3
KEY CONCEPT
Development progresses in stages from zygote to
fetus.
31.1 Pathogens and Human Illness
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
– ectoderm develops into skin and nervous system
BUT
DON’T – mesoderm develops into Internal tissues and organs
COPY
– endoderm develops into digestive organs and their
lining
blastocyst
uterine
wall
Implantation
of blastocyst
31.1 Pathogens and Human Illness
• The blastocyst becomes an embryo.
• Embryonic membranes protect and nourish the embryo.
– amniotic sac cushions
embryo.
– placenta connects
placenta
mother and embryo.
umbilical
– umbilical cord
cord
connects embryo to
uterus
placenta.
amniotic sac
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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
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– 2nd trimester: fetus more active, developed
– Leave a few lines for notes here
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– 3rd trimester: all organs fully formed
– Leave a few lines for notes here
• After about 38 weeks, fetus is ready to be born.
31.1 Pathogens and Human Illness
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
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• 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