Human Body Systems

Section 35–1

Human Body Systems

Organization of the Body

• List the levels of organization in a multicellular organism, from smallest to largest. – Cells – Tissues

– Organs– Organ systems

Nervous system Coordinates the body’s response to changes in its

internal and external environments

Skeletal system   Stores mineral reserves and provides a site for

blood cell formation

Integumentary system   Serves as a barrier against infection and injury

Endocrine system    Eliminates wastes and maintains homeostasis

Lymphatic/Immune systems Helps protect body from disease.

Muscular system Helps produce voluntary movement, circulate

blood, and move food

Reproductive system Produces reproductive cells

Respiratory system Provides oxygen and removes carbon dioxide

Excretory system Eliminates wastes and maintains homeostasis

Circulatory system Brings materials to cells, fights infection, and helps

to regulate body temperature

Digestive system Converts food so it can be used by cells

Maintaining Homeostasis

• The process of maintaining a controlled, stable internal environment is called

• homeostasis

Maintaining Homeostasis

• What happens if nerve cells sense that the core body temperature has dropped below 37°C?

• The hypothalamus produces chemicals that signal cells throughout the body to speed up their activities, which causes a gradual rise in body temperature.

Maintaining Homeostasis

• What happens if the body temperature rises too far above 37°C?

• The hypothalamus slows down cellular activities, minimizing the production of heat.

Negative Feedback

• when a change in the normal state occurs a negative feedback mechanism causes the body to return to the normal state. Most common way for the body to return to homeostasis.

Examples: • You get overheated, so your body starts to

sweat, and you cool back off

What mechanisms are there to cool the body down?

1. Sweating• When your body is hot, sweat glands are

stimulated to release sweat.

• The liquid sweat turns into a gas (it evaporates)

• To do this, it needs heat.

• It gets that heat from your skin.

• As your skin loses heat, it cools down.

Negative Feedback

• Blood pressure gets too high, so your heart beats slower, and blood pressure returns to normal.

More examples• Your glucose (sugar)

levels in your blood get to high, so the pancreases secretes insulin, causing your body’s cells to store the glucose, until levels return to a normal level.

12

Digestion• Processing of food• Types

– Mechanical (physical)• Chew• Tear• Grind• Mash• Mix

– Chemical• Catabolic reactions• Enzymatic hydrolysis

– Carbohydrate– Protein– Lipid

• Digestion- the mechanical and chemical breakdown of foods for use by the body’s cells.

• Absorption- the passage of digested food from the digestive tract into the cardiovascular system.

• Elimination- the expulsion of undigested food or body wastes.

Digestion includes both mechanicalmechanical and

chemicalchemical processes.

•The mechanical portion involves

chewing, mashing, and breaking food into

smaller pieces.

•The chemical process involves digestive juices

that change food into simpler substances.

The NNervouservous and cardiovascularcardiovascular systems also play a major role in the digestion process.

• The nervous system triggers the digestive process

• Nutrients are carried through the body by the cardiovascular system.

1. Food processing starts with ingestion (eating).• Teeth- mechanical digestion by

masticating (chewing) food.

2. Upon entering esophagus, peristalsis (wave-like contractions) of smooth muscle carries the bolus (food ball) toward the stomach.

3. From the esophagus, bolus passes through a sphincter (muscular ring) into the stomach.

5. Gallbladder contains Bile from liver that emulsifies (breaks into small particles) lipids (fats), which helps mechanical digestion of fats.

6. Tiny villi (finger-like projections) cover walls of small intestine. This increased surface area causes more efficient food absorption

7. Parts of the colon absorb water and minerals from undigested food and compact the remaining material into feces.

4. In the stomach, food undergoes chemical and mechanical digestion.

Points of Interaction

Food leaves the digestive system and enters the circulatory system in the small intestine at points called villi. Process called absorption.

Things your Cell needs to get daily

From your digestive system:

NutrientsMineralsLipidsCarbohydratesProtiensWater

From your respiratory system:

Oxygen

Enzymes: are proteins that help speed up chemical reactions and help your body get these things.

Then the Cell needs to get rid of… C02 using the respiratory system.

Extra water, minerals, and other cellular waste though the excretory system.

This process is called EXCRETION.

The Respiratory SystemSection 4

Breathing

• The Diaphragm Breathing is done by the diaphragm and rib muscles. The diaphragm is a dome-shaped muscle beneath the lungs.

Copyright © by Holt, Rinehart and Winston. All rights reserved.

• Oxygen In cellular respiration, oxygen is used by cells to release energy stored in molecules of glucose. When you breathe, you take in oxygen. Oxygen diffuses into red blood cells and is carried to tissue cells. The cells in turn use the oxygen to carry on normal life processes. This process is illustrated on the next slide.

Breathing and Cellular Respiration

The Respiratory SystemSection 4

Respiration and the Respiratory System

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• Nose, Pharynx, and Larynx Your nose is the main passageway into and out of the respiratory system. From the nose, air flows into the pharynx, or throat. The larynx is the part of the throat that contains the vocal chords.

• Trachea The larynx guards the entrance to a large tube called the trachea, or windpipe.

• Bronchi and Alveoli The trachea splits into two branches called bronchi. One bronchus connects to each lung. In the lungs, each bronchiole branches to form thousands of tiny sacs that are called alveoli. Oxygen enters the blood when CO2 enters the alveoli, completing the exchange with the capillaries.

The Role of Blood in RespirationSection 4

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The Cardiovascular SystemSection 1

Your Cardiovascular System

• Main Components of the Cardiovascular System The cardiovascular system consists of the heart and the three types of blood vessels that carry blood throughout your body.

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• Cardiac Muscle Your heart is an organ made mostly of cardiac muscle tissue. It is about the size of your fist and is almost in the center of your chest cavity. The next slide shows the flow of blood through the heart.

The Heart

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The Flow of Blood Through the HeartSection 1

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Makeup of Heart• Has two sides(left and right) that are

separated by a thick wall.

• Each side has an upper(Atrium) chamber and a lower(Ventricle) chamber.

• The blood enters the Atriums first. The left atrium receives oxygen-rich blood from the lungs. The right atrium receives oxygen-poor blood from the body.

Makeup Continued

• When the Atria contract they squeeze blood into the ventricles.

• Blood from the right ventricle goes to the lungs. Blood from the left ventricle goes to the body.

The Beating Heart

• On body sides of the heart located between the Atriums and the Ventricles are valves.

• These valves open and close to prevent blood from flowing backwards.

• The opening and closing is what causes the “beating” of the heart.

The Cardiovascular SystemSection 1

Blood Vessels – tubes that blood travels throughout the body in. • Arteries A blood vessel that carries blood away from the heart is an artery. Artery walls are very thick which allows them to change shape due to blood pressure. As your heart beats it pumps blood into your arteries. This is what causes blood pressure.

• Capillaries A capillary is a tiny blood vessel that allows nutrient, oxygen, carbon dioxide , and waste exchanges between body cells and blood.

• Veins A vein is a blood vessel that carries blood back to the heart from the contraction of the skeletal muscles.

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The Cardiovascular SystemSection 1

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• Pulmonary Circulation This circulation of blood between your heart and lungs is called pulmonary circulation.

• Systemic Circulation The circulation of blood between the heart and the rest of the body is called systemic circulation. Both systemic and pulmonary circulation are illustrated on the next slide.

Two Types of Circulation

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The Flow of Blood Through the BodySection 1

Copyright © by Holt, Rinehart and Winston. All rights reserved.