Chapter 3 Mixed Test

Human Function and Interacting Systems

• Healthy human function relies on interacting systems.
• Organ systems depend on each other for optimal function.

Key Concepts

• Cells
• Organs
• Tissues
• Structure and function
• Response to stimuli
• Systems

Learning Outcomes

• Describe how body systems work.
• Recognize roles of organs/tissues in body systems.
• Explain how cells help the body function.
• Show how the body responds to changing conditions.

Digestive System

• Living organisms need energy from carbohydrates, lipids, and proteins.
• The digestive system breaks down food into smaller, usable particles.
• Mechanical digestion breaks food into smaller pieces.
• Chemical digestion uses enzymes to further break down large molecules.
• Digestion takes place in different parts of the digestive system.

The Mouth and Esophagus

• Digestion begins in the mouth.
• Teeth mechanically break down food.
• Saliva moistens food and contains enzymes (salivary amylase) that breaks down starch.
• Epiglottis prevents food from entering the trachea.
• Food travels through the esophagus by peristalsis (wave-like muscle contractions).

The Stomach

• The stomach churns food.
• Gastric juice (mucus, hydrochloric acid, water, and digestive enzymes) mixes with food.
• Hydrochloric acid chemically digests proteins.
• Mucus protects the stomach lining from digestion.
• Food is slowly released into the small intestine as a liquid.

The Small Intestine, Pancreas, Liver, and Gallbladder

• Chemical digestion continues in the small intestine.
• Pancreas releases digestive enzymes.
• Liver produces bile, stored in the gallbladder.
• Bile breaks down fats.
• Small intestine absorbs nutrients.
• Villi and microvilli increase surface area for absorption.
• Nutrients are absorbed into the bloodstream.

The Large Intestine

• Water and vitamins are absorbed.
• Undigested material forms feces.
• Feces are expelled through the rectum.

Respiratory System

• The respiratory system supplies oxygen to the blood and removes carbon dioxide.
• Breathing involves inhaling and exhaling air.
• The process of exchanging gases takes place in the alveoli.
• Alveoli are tiny air sacs in the lungs, surrounded by capillaries.
• Oxygen diffuses into the blood, and carbon dioxide diffuses out.

Circulatory System

• The circulatory system transports nutrients and oxygen.
• It removes waste products.
• The heart pumps blood through arteries, veins, and capillaries.
• Arteries carry blood away from the heart.
• Veins carry blood to the heart.
• Capillaries exchange substances with tissues.

The Heart

• The heart acts as a pump with two sides.
• The right side pumps blood to the lungs.
• The left side pumps oxygenated blood to the body.
• The heart has four chambers (two atria and two ventricles).

Arteries, Veins, and Capillaries

• Arteries have thicker walls than veins to withstand the pressure of the pumping heart.
• Veins have valves to prevent backflow.
• Capillaries are thin-walled to facilitate diffusion.

Excretory System

• The excretory system removes waste products like urea and excess water.
• Kidneys filter urea and wastes from blood creating urine.
• Urine travels to the bladder for storage.
• Urine is expelled from the body.
• Other parts like skin and lungs also remove waste.

Nervous System

• The nervous system receives stimuli and sends messages to react.
• Sensory nerves detect changes (stimuli).
• Motor neurons (message carriers) trigger responses.
• The brain and spinal cord form the central nervous system.
• Nerves make up the peripheral system.