Ms. Aguirre Chapter 1 Lesson 2

Human body systems from cells to systems We already know that tissue combines to form organs organs combine to form systems systems work together to keep us alive

We need all of our systems. One system alone would not keep us alive For example the digestive system breaks down nutrients but the circulatory helps us release the energy we get from those nutrients. And without the respiratory system, oxygen couldn’t get into the circulatory system

circulatory Transports oxygen, nutrients, and wastes through the body in the blood.

Plasma- liquid part of the blood But also contains dissolved nutrients and waste products, such as carbon dioxide. The solid part is white and red blood cells

Red blood cells Carry oxygen from air to lungs and transport it to every cell in the body.

White blood cells White blood cells help the body to fight infection. They attack and destroy viruses and bacteria that enter the body.

Platelets-tiny pieces of blood cells that cause blood to clot when a blood vessel is cut. They also help repair damage.

Oxygen-rich blood from the lungs enters one chamber then another Oxygen-rich blood from the lungs enters one chamber then another. After that it enters to the body Oxygen-poor blood from the body enters the third chamber, moves to the fourth and into the lungs.

Blood leaves the heart through blood vessels called arteries

Arteries lead to capillaries Capillaries are blood vessels so small that blood cells have to move them in single file.

There are capillaries throughout our whole body so nutrients and oxygen can reach every cell.

Waste products from cells are picked up by plasma in the capillaries Capillaries lead to larger vessels called veins which return blood to the heart.

The Respiratory System Your body uses a lot of energy so your cells need a lot of food and oxygen. You get the oxygen your cells need by breathing

The air travels through your nose to your trachea The air travels through your nose to your trachea. The trachea leads to two tubes called the bronchi. Each tube leads to the lungs.

Bronchi Each bronchial tube divide into smaller and smaller tubes

At the end of each tube are tiny sacs called alveoli

The capillaries surrounding the alveoli get blood from the pulmonary arteries coming from the heart. This blood contains a lot of carbon dioxide that diffuses through the alveoli and into the air that will be exhaled.

At the same time, oxygen inhaled diffused into the alveoli and into the red blood cells in the capillaries. This oxygen rich blood then flows to the veins and back to the heart. Then the blood is pumped to other parts of the body

The digestive system Performs two functions Break food into nutrients Gets nutrients to the blood

Digestion begins with chewing food Digestion begins with chewing food. Saliva moistens and breaks down food to sugars.

When you swallow, food goes through your esophagus

Gastric juice produced by the stomach contains acid that break down proteins

Digestion is completed by chemicals produced in the small intestine After several hours in the stomach, partly digested food moves to the small intestine. Digestion is completed by chemicals produced in the small intestine

Nutrients diffuse through the villi and into the blood. They are projections sticking out of the walls of the small intestine.

From the small intestine undigested food passes in the large intestine.

Here, water and minerals diffuse in the blood and wastes are removed

Liver produces bile which is stored in the gallbladder until it’s needed. Bile breaks down fats into smaller particles so they are easier to digest.

Pancreas- produces a fluid that neutralizes stomach acid that help finish digestion

The excretory system This is the system for removing waste from the blood. Cell wastes include ammonia and carbon dioxide

The respiratory gets rid of carbon dioxide

Ammonia is carried by the blood to the liver where it is changed to urea. From the liver urea is carried by the blood to the kidneys urea and water diffuse into tubes called nephrons

Urea and water = urine flows from the kidneys through ureters Then is emptied to the bladder When the bladder is full urine leaves through the urethra

Sweating is a salty liquid that evaporates from the skin Sweating is a salty liquid that evaporates from the skin. The blood and entire body are cooled