Transcript Objectives For Chapter 25

Objectives For Chapter 25

 Describe the relationship between the central nervous system and the
peripheral nervous system.
 Compare the somatic nervous system with the autonomic nervous
system.
 List one function of each part of the brain.
 List four sensations that are detected by receptors in the skin.
 Describe how a feedback mechanism works.
 Describe how light relates to sight.
 Describe how the senses of hearing, taste, and smell work.
 Explain why the endocrine system is important to the body.
 Identify five glands of the endocrine system, and describe what their
hormones do.
 Describe how feedback mechanisms stop and start hormone release.
 Name two hormone imbalances.
The Nervous System
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 The central nervous system (CNS) includes the brain and the spinal
cord.
 The peripheral nervous system (PNS) is all the parts of the nervous
system except the brain and spinal cord.
 The peripheral nervous system has nerves made of axons of neurons.
 Sensory neurons have receptors that detect information about the body
and its environment. Motor neurons carry messages from the brain
and spinal cord to other parts of the body.
 The PNS has two types of motor nerves: somatic nerves and
autonomic nerves.
 The cerebrum is the largest part of the brain and controls thinking,
sensing, and voluntary movement.
 The cerebellum is the part of the brain that keeps track of the body’s
position and helps maintain balance.
 The medulla controls involuntary processes, such as heart rate, blood
pressure, body temperature, and breathing.
Responding to the
Environment

 Touch allows you to respond to temperature,
pressure, pain, and vibration on the skin.
 Reflexes and feedback mechanisms help you respond
to your environment.
 Sight allows you to respond to light energy.
 Hearing allows you to respond to sound energy.
 Taste allows you to distinguish flavors.
 Smell allows you to perceive different odors.
The Endocrine System
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 Glands in the endocrine system use chemical
messengers called hormones to control bodily
functions.
 Hormones regulate body functions by causing
changes in cells or tissues.
 Feedback mechanisms tell endocrine glands when to
turn hormones on and off.
 A hormone imbalance is when a gland releases too
much or too little of a hormone.
Objectives For Chapter 26

 Distinguish between sexual and asexual reproduction.
 Explain the difference between external and internal
fertilization.
 Identify three different types of mammalian reproduction.
 Identify the structures and functions of the male and
female reproductive systems.
 Describe two reproductive system problems.
 Summarize the processes of fertilization and
implantation.
 Describe the development of the embryo and the fetus.
 Identify the stages of human development from birth to
death.
Animal Reproduction
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 In asexual reproduction, a single parent produces
offspring that are genetically identical to the parent.
 In sexual reproduction, an egg from one parent
combines with a sperm from the other parent.
 Fertilization can be external or internal.
 All mammals reproduce sexually and nurture their
young with milk.
Human Reproduction
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 The male reproductive system produces sperm and
delivers it to the female reproductive system.
 The female reproductive system produces eggs,
nurtures developing individuals, and gives birth.
 Humans usually have one child per birth, but
multiple births, such as those of twins or triplets, are
possible.
 Human reproduction can be affected by cancer,
infertility, and disease.
Growth and
Development
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 Fertilization occurs when a sperm from the male joins with an
egg from the female and their nuclei fuse.
 The fertilized egg (zygote) becomes an embryo once the first
cell division occurs.
 Eleven to twelve days after fertilization implantation occurs,
which is the embedding of the embryo in the thick, nutrientrich lining of the uterus.
 The embryo and fetus undergo many changes between
implantation and birth.
 The first stage of human development lasts from fertilization to
birth.
 After birth, a human goes through four more stages of growth
and development.
Stages of Development
 Weeks 1 and 2 – Doctors commonly count the time of a
woman’s pregnancy as starting from the first day of her last
menstrual period. A normal pregnancy lasts about 40 weeks.
 Weeks 3 and 4 – The zygote becomes an embryo as it moves to
the uterus. At the end of week 4 implantation occurs.
 Weeks 5 to 8 – The umbilical cord forms, which connects the
embryo to the placenta. The heart, brain, other organs, and
blood vessels start to form. Eyes and ears take shape, spinal
cord begins to develop, tiny limb buds appear, muscles start to
develop, nerves grow into the arms and shoulders, fingers and
toes start to form, and the embryo can swallow and blink.
 Weeks 9 to 16 – The embryo begins to make tiny movements,
embryo is called a fetus.
 Week 17 to 24 – The fetus can make faces and starts to make
movements the mother can feel.
 Week 25 to 36 – The fetus’s lungs are well developed, but not
fully matured. The fetus still gets oxygen from its mother
through the placenta. The fetus’s eyes can open and close.
Stages of Development
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 Birth – The fetus is fully developed and labor occurs.
 Infancy and childhood – Infancy is the stage from birth to age 2.
During infancy you grow quickly, your baby teeth appeared,
and your nervous system developed allowing you to become
more coordinated and you start to walk. Childhood lasts from
age 2 to puberty. Your baby teeth are replaced by permanent
teeth, and your muscles become more coordinated.
 Adolescence – The stage from puberty to adulthood. A person’s
reproductive system becomes mature.
 Adulthood – From about age 20 to 40, you are a young adult. At
around age 30 changes associated with aging begin. The aging
process continues in middle age (between 40 and 65). A person
who is more than 65 years old is considered an older adult.
Objectives For Chapter 27
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 Explain the differences between infectious diseases
and noninfectious diseases.
 Identify five ways that you might come into contact
with a pathogen.
 Discuss four methods that have helped reduce the
spread of disease.
 Describe how your body keeps out pathogens.
 Explain how the immune system fights infection.
 Describe four challenges to the immune system.
Disease
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 Noninfectious diseases cannot be spread from one person
to another.
 Infectious diseases are caused by pathogens that are
spread from one organism to another.
 Pathogen – a microorganism, another organism, a virus, or a
protein that causes disease.
 Pathogens are spread by contact with infected organisms
and through contaminated objects, food, water, or air.
 Cleanliness, antibiotics, pasteurization, vaccines, and
antiviral medicines help control diseases.
 Pasteurization- the heating of material to kill bacteria.
 Antibiotics can kill only living things. Viruses are not
considered to be alive because they cannot reproduce on
their own.
Your Body’s Defenses
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 Macrophages engulf pathogens, display antigens on their surface,
and activate helper T cells. The helper T cells put the killer T cells
and B cells to work.
 Killer T cells kill infected cells. B cells make antibodies.
 Fever helps speed immune-cell growth and slow pathogen growth.
 Memory B cells remember how to make an antibody for a
pathogen that the body has previously fought.
 An allergy is the overreaction of the immune system to a harmless
antigen.
 Autoimmune diseases are responses in which the immune system
attacks healthy tissue.
 Cancer cells are cells that undergo uncontrolled division.
 AIDS is a disease that results when the human immunodeficiency
virus kills helper T cells.
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In place of a summary, describe
how the body systems meet the
needs of cells