• organ system

• homeostasis

• nutrient

• Calorie

Transport and Defense

• lymphocyte

• immunity

The liver makes bile and the pancreas makes enzymes, both of which break down food in the small intestine.

Digestion (cont.)

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• The large intestine receives solid waste from the small intestine.

• The large intestine absorbs excess water from the waste material.

• The rectum of the large intestine stores the solid waste until the waste is expelled from the body.

Digestion (cont.)

Some foods, like insoluble fiber, that are not digested leave the body through the rectum.

Digestion (cont.)

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• When the liver breaks down proteins, urea forms. Urea is toxic if it stays in the body.

• The kidneys remove urea from the body by making urine.

Excretion (cont.)

• Urine leaves each kidney through the ureter and is stored in a flexible sac, called the bladder.

• Urine is removed from the body through the urethra.

Excretion (cont.)

Respiration (cont.)

Gas Exchange

• Oxygen in the alveoli enters the capillaries.

• The blood inside capillaries transports oxygen to the rest of the body.

Circulation

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• Blood vessels transport blood to all organs of the body.

• Contractions of the heart’s muscles pump blood to the rest of the body.

• Blood travels through the body in tiny tubes called vessels.

Circulation (cont.)

• Arteries carry blood away from your heart.

• Veins carry blood back to your heart.

Circulation (cont.)

Capillaries are tiny vessels that allow gases and nutrients to move between the blood and the entire body.

Circulation (cont.)

• Humans make billions of different types of antibodies.

• Infectious diseases are caused by pathogens, such as bacteria and viruses, and are usually contagious.

• A noninfectious disease is caused by the environment or a genetic disorder.

Immunity (cont.)

• compact bone

• spongy bone

• neuron

Structure, Movement, and Control

• reflex

• hormone

• The skeletal system protects internal organs, provides support, helps the body move, and stores minerals, such as calcium.

• An adult’s skeleton has 206 bones.

• The skeleton also contains ligaments, tendons, and cartilage.

Structure and Movement

• Compact bone is the hard outer layer of bone.

• Spongy bone is the interior region of bone that contains many tiny holes.

Structure and Movement (cont.)

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• The muscular system is made of three different types of muscle tissue.

• Skeletal muscle works with the skeletal system and helps you move.

Structure and Movement (cont.)

• Cardiac muscle is only in the heart.

• It continually contracts and relaxes and moves blood throughout your body.

Structure and Movement (cont.)

• Smooth muscle tissue is in organs such as the stomach and the bladder.

• Blood vessels also have smooth muscle tissue.

Structure and Movement (cont.)

• The brain and the spinal cord form the central nervous system.

• All other nerves are part of the peripheral nervous system that extends throughout the entire body.

Control and CoordinationD

oug Pensinger/G

etty Images

The nervous system is a group of organs and specialized cells that detect, process, and respond to information.

Control and Coordination (cont.)

• Information enters the nervous system through neurons in the peripheral nervous system.

• Most of the information then is sent to the central nervous system for processing.

• After the central nervous system processes information, it signals the peripheral nervous system to respond.

Control and Coordination (cont.)

The endocrine system, like the nervous system, sends signals to the body.

Endocrine System

Mark Andersen/Getty Images

• Chemical signals released by the organs of the endocrine system are called hormones.

• Hormones travel in blood through blood vessels and cause organ systems to carry out specific functions.

• Some hormones work with other organ systems to maintain homeostasis and other hormones work with many organ systems to help you grow.

Endocrine System (cont.)