Science - Organ Systems Working Together (Grade 8)

A comprehensive set of practice questions covering the human digestive and excretory systems, their interactions with other organ systems, and plant organ functions based on Grade 8 Science notes.

What is the definition of an organ system?

An organ system is a group of organs that work together to perform a specific function necessary for the survival of an organism.

What is the main function of the Respiratory System?

Exchanges oxygen and carbon dioxide.

What is the main function of the Circulatory System?

Transports nutrients, oxygen, and wastes.

What are the three main purposes for which the body uses nutrients provided by the digestive system?

Growth, Energy, and Repair of damaged tissues.

What enzyme is found in saliva and what is its function?

Salivary amylase; it breaks down starch into simpler sugars.

What is the term for the wave-like contraction of muscles that pushes food through the esophagus?

Peristalsis

Which two substances are found in the stomach to assist in protein digestion?

Hydrochloric acid (HCI) and the Pepsin enzyme.

What is the name of the semi-liquid mixture created when the stomach churns food with gastric juices?

Chyme

What are the three parts of the small intestine?

Duodenum, Jejunum, and Ileum.

What are villi and what is their function?

Villi are finger-like projections in the small intestine that increase the surface area for nutrient absorption into the bloodstream.

What is the function of the Large Intestine?

Absorbs water and forms feces.

Which organ produces bile and what is its purpose?

The Liver; it produces bile to break large fat droplets into smaller droplets through a process called Emulsification.

What is the function of the Gallbladder?

Stores bile until needed.

List the path of food through the digestive tract in order.

Mouth, Pharynx, Esophagus, Stomach, Small Intestine, Large Intestine, Rectum, Anus.

In the digestive system, what is Secretion?

The release of digestive juices such as saliva, gastric juice, bile, and pancreatic juice to help break down food chemically.

Where does the absorption of glucose, amino acids, and vitamins mainly occur?

Small intestine

What metabolic wastes do the kidneys remove from the blood?

Urea, excess water, and excess salts.

Trace the flow of urine from production to elimination.

Kidneys, Ureters, Urinary Bladder, Urethra, Outside the Body.

How do the Digestive and Respiratory systems work together to produce energy?

The digestive system provides glucose and the respiratory system provides oxygen; cells combine these to produce energy.

What is the function of the Xylem in a plant's stem?

It carries water upward from the roots.

What is the function of the Phloem in a plant's stem?

It carries food to all plant parts.

What is the word equation for photosynthesis?

$$\text{Carbon dioxide} + \text{Water} + \text{Sunlight} \rightarrow \text{Glucose} + \text{Oxygen}$$

What role do roots play in plant organ interaction?

They absorb water and minerals and anchor the plant.