MS-LS1-3: Body Systems and Functions

MS-LS1-3
Body Systems and Functions

Middle School

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Learning Objectives

• Describe the body's organization, from cells to tissues, organs, and organ systems.

• Explain how the human body is a system of multiple interacting subsystems.

• Identify the major organs and functions of the body’s main organ systems.

• Explain how organ systems interact to support essential life functions like growth.

Key Vocabulary

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Cell

The cell is the basic structural and functional unit of all living organisms.

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Tissue

A tissue is a group of specialized cells that work together to perform a common function.

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Organ

An organ is a structure made of different types of tissues that work together for a purpose.

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Organ System

An organ system is a group of organs that cooperate to perform major functions in the body.

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Subsystem

A subsystem is a self-contained system that functions as part of a larger, more complex system.

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Hormones

Hormones are chemical messengers that are produced in glands and travel in the bloodstream to tissues.

Key Vocabulary

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Neurons

Neurons are special nerve cells that transmit important electrical and chemical signals throughout the body.

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Homeostasis

Homeostasis is the essential process by which the body maintains a stable and balanced internal environment.

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Capillaries

Capillaries are extremely tiny blood vessels where the important exchange of nutrients and gases occurs.

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Alveoli

Alveoli are the very tiny air sacs located in the lungs for essential gas exchange.

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Bone Marrow

Bone marrow is the soft, spongy tissue inside of bones that is responsible for producing blood cells.

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Hemoglobin

Hemoglobin is an iron-rich protein found in red blood cells that transports vital oxygen.

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The Body: A System of Systems

• Your body is a system of many smaller subsystems that work together.

• ​Specialized cells with the same job group together to form body tissues.

• Different kinds of tissues work together to form specialized organs, like the heart.

• The heart uses muscle and nervous tissues to help it pump blood.

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Multiple Choice

What is formed when specialized cells with the same job group together?

• An organ system

• A body tissue

• A single cell

• A specialized organ

Multiple Choice

What is the relationship between tissues and organs in the body?

• Organs are made of a single, large type of tissue.

• Tissues are complex systems, and organs are the cells inside them.

• Different kinds of tissues work together to form an organ.

• Organs break down to create the tissues the body needs.

Multiple Choice

The heart organ uses both muscle tissue to contract and nervous tissue to send signals. What conclusion does this evidence support about how the body is organized?

• The heart is the only organ that uses more than one tissue.

• An organ needs different tissues to perform all its different jobs.

• Muscle tissue and nervous tissue are part of the same system.

• All organs are made of exactly the same kinds of tissues.

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How Systems Interact: A Team Effort

• No organ system works alone; they interact to keep the organism alive.

• The digestive system breaks down food, and the respiratory system takes in oxygen.

• The circulatory system transports these nutrients and oxygen to every single cell.

• Your cells use them for energy, growth, and to repair the body.

Multiple Choice

What is the main reason that different organ systems interact with each other?

• To work together to keep the organism alive

• To help the organism move from place to place

• To make sure each system grows at the same rate

• To store food and water for later use

Multiple Choice

Once the digestive system breaks down food and the respiratory system takes in oxygen, how do these substances reach the body's cells?

• The respiratory system sends them directly to the cells.

• The digestive system delivers both directly to the cells.

• The circulatory system transports them to the cells.

• The cells create their own nutrients and oxygen.

Multiple Choice

If the circulatory system failed, what would be the most direct consequence for the body's cells?

• The digestive system would immediately stop breaking down food.

• The respiratory system would stop taking in oxygen from the air.

• Cells would not get the nutrients and oxygen they need for energy and growth.

• The body would start using carbon dioxide for energy instead.

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What is the Circulatory System?

• The circulatory system is the body's main transportation network.

• It includes the heart, blood vessels (arteries, veins), and blood.

• The heart pumps blood, carrying oxygen and nutrients to all body cells.

• Blood also removes waste and helps your body fight off diseases.

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Multiple Choice

What is the main function of the circulatory system?

• To break down food into usable energy.

• To send electrical signals to the brain.

• To provide the body with structure and support.

• To move essential materials throughout the body.

Multiple Choice

How does the heart help the circulatory system perform its main function?

• By creating the nutrients the body needs.

• By filtering waste products out of the blood.

• By pumping blood that carries oxygen and nutrients.

• By producing cells that can fight off diseases.

Multiple Choice

Based on its functions, what would be the most critical impact if the circulatory system stopped working correctly?

• The body would have no way to fight off infections and diseases.

• Waste materials would immediately stop being produced by the cells.

• Body cells would be unable to get the oxygen and nutrients needed to survive.

• The arteries and veins would be unable to hold all the blood.

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The Digestive System

• The digestive system is a long tube that breaks down food into nutrients.

• ​Digestion starts in the mouth and food moves through the esophagus via peristalsis.

• The stomach uses acid, and the small intestine absorbs most of the nutrients.

• The large intestine absorbs water and prepares solid waste for removal.

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Multiple Choice

What is the main function of the digestive system?

• To break down food into nutrients the body can use

• To pump blood to all parts of the body

• To exchange oxygen and carbon dioxide

• To remove liquid waste from the blood

Multiple Choice

What is the key difference between the function of the small intestine and the large intestine?

• The small intestine absorbs nutrients, while the large intestine absorbs water.

• The stomach absorbs water, while the small intestine uses acid.

• The esophagus breaks down food, while the stomach absorbs nutrients.

• The small intestine prepares solid waste, while the large intestine moves food with acid.

Multiple Choice

If a person's small intestine was unable to perform its job, what would be the most likely outcome?

• Food would not be moved from the mouth to the stomach.

• Acid would not be able to break down food in the stomach.

• Nutrients from food would not be absorbed, and the body would lack energy.

• Water would not be absorbed, leading to very dry solid waste.

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The Excretory System

• The excretory system removes toxic wastes and balances water and salts.

• The main organs are the kidneys, ureters, bladder, and urethra.

• Kidneys are key organs that filter your blood to produce urine.

• The liver also helps by turning harmful ammonia into safer urea.

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Multiple Choice

What is the main function of the excretory system?

• To remove wastes and balance water in the body.

• To break down food and absorb nutrients.

• To pump blood throughout the body.

• To help the body move and maintain posture.

Multiple Choice

What is the specific role of the kidneys within the excretory system?

• They store urine before it is removed.

• They filter waste from the blood to make urine.

• They turn harmful ammonia into safer urea.

• They carry urine from the kidneys to the bladder.

Multiple Choice

Based on the information provided, what would most likely happen if a person's liver could no longer turn ammonia into urea?

• The body would not be able to filter blood.

• Harmful ammonia would build up in the body.

• The bladder would not be able to store urine.

• Water and salt levels would become perfectly balanced.

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The Respiratory System

• The respiratory system takes in vital oxygen and removes waste carbon dioxide.

• ​Its main parts are the airway, lungs, and the muscles for breathing.

• The airway carries air to tiny sacs in the lungs called alveoli.

• Here, oxygen enters the blood and carbon dioxide is removed to be exhaled.

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Multiple Choice

What is the main purpose of the respiratory system?

• To take in oxygen and remove carbon dioxide.

• To pump blood to all parts of the body.

• To break down food into useful nutrients.

• To control movement and process information.

Multiple Choice

How do the airway and lungs work together in the respiratory system?

• The airway carries air to the alveoli, which are located in the lungs.

• The lungs clean the air and the airway then exhales it.

• The airway exchanges gases and the lungs store the leftover air.

• The lungs are muscles that contract to push air through the airway.

Multiple Choice

If the alveoli stopped working correctly, what would be the most direct result?

• Air would no longer be able to enter the airway.

• The breathing muscles would stop working.

• Oxygen would not be able to enter the blood.

• Carbon dioxide would be stored in the airway.

The Muscular System

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Skeletal Muscle

• ​This is a voluntary muscle, meaning you control its movement.

• ​​These muscles are attached to bones and are found throughout the body.

• ​They work in pairs to help your skeleton move.

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Smooth Muscle

• ​This is an involuntary muscle, so you do not control it.

• ​​It is found in the walls of internal organs like the stomach.

• ​It moves substances like food and blood through the body.

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Cardiac Muscle

• ​This is an involuntary muscle that is only found in the heart.

• ​​It is responsible for pumping blood to all parts of your body.

• ​This muscle works constantly without you ever needing to think about it.

Multiple Choice

Which type of muscle is voluntary, meaning you can consciously control its movement?

• Skeletal muscle

• Smooth muscle

• Cardiac muscle

• Stomach muscle

Multiple Choice

What is the key reason why muscles in the heart and stomach are involuntary?

• They are responsible for moving the body's skeleton.

• They perform essential functions automatically without conscious thought.

• They are only found attached to the body's bones.

• They require conscious commands to do their jobs.

Multiple Choice

During a soccer game, a player sprints to kick the ball. Which two muscle types must work together to allow for the sprinting and the increased heart rate that comes with it?

• Skeletal muscles to move the legs and cardiac muscle to pump blood faster.

• Smooth muscles to digest food and skeletal muscles to move the arms.

• Cardiac muscle to control breathing and smooth muscle to move the legs.

• Skeletal muscles to control the heart and cardiac muscle to move the legs.

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The Nervous System

• The nervous system is the body’s main communication and control center.

• It has two parts: the central and the peripheral nervous systems.

• The cerebrum controls thinking, the brain stem breathing, and cerebellum balance.

• It receives information from senses and sends instructions to your muscles.

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Multiple Choice

What is the main role of the nervous system in the body?

• To act as the body’s communication and control center

• To pump blood and oxygen throughout the body

• To break down food and absorb nutrients

• To provide structure and support for the body

Multiple Choice

How does the nervous system direct the body's actions?

• By receiving information from senses and sending instructions to muscles

• By creating new cells for growth and repair

• By filtering waste products from the blood

• By storing energy for later use in the bones

Multiple Choice

A student is thinking about what to say while walking on a narrow balance beam. Which parts of the brain are primarily responsible for these two tasks?

• The cerebrum for thinking and the cerebellum for balance

• The brain stem for thinking and the cerebrum for balance

• The cerebellum for breathing and the brain stem for balance

• The cerebrum for breathing and the cerebellum for thinking

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Common Misconceptions

Misconception	Correction
Organ systems work all by themselves.	All organ systems work together to keep you healthy and alive.
Organs are made of only one type of tissue.	Organs are made of different types of tissues working together.
Bones are not alive; they are just hard and solid.	Bones are living organs with cells that grow and repair themselves.

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Summary

• The body is organized in a hierarchy from cells to organ systems.

• The circulatory system transports vital nutrients and oxygen to all the body's cells.

• The nervous system is the body’s command center, controlling movement and other systems.

• All organ systems must interact to maintain balance and ensure survival.

Poll

On a scale of 1-4, how confident are you about how the body's organ systems interact as a larger system?

• 1

• 2

• 3

• 4