body systems

Question 1

What are the four main macromolecules broken down by the digestive system?

Answer 1

Starch, proteins, fats, nucleic acids.

Question 2

What enzyme in saliva begins the digestion of starch?

Answer 2

Salivary amylase.

Question 3

What is the chewed and moistened food called in the mouth?

Answer 3

Bolus.

Question 4

What are the functions of the stomach in digestion?

Answer 4

Temporarily stores food, begins protein digestion, and kills bacteria.

Question 5

What substances are found in gastric juice?

Answer 5

digestive enzymes and hydrochloric acid (HCl).

Question 6

Which enzyme in the stomach breaks down proteins?

Answer 6

Pepsin

Question 7

What is chyme?

Answer 7

Partially digested food that enters the small intestine.

Question 8

How long is the small intestine?

Answer 8

About 23 feet.

Question 9

Where does complete digestion of food occur?

Answer 9

Small intestine.

Question 10

What enzymes are secreted by the small intestine walls to digest proteins and carbohydrates?

Answer 10

Peptidases (for proteins), maltase, lactase, sucrase (for carbohydrates).

Question 11

What structures in the small intestine absorb nutrients?

Answer 11

Microvilli and villi.

Question 12

How do absorbed nutrients from the small intestine enter the body?

Answer 12

Through the bloodstream.

Question 13

What is the primary function of the large intestine?

Answer 13

Reabsorption of water and salt.

Question 14

What is the role of hydrochloric acid (HCl) in the stomach?

Answer 14

Helps kill bacteria and activates digestive enzymes.

Question 15

What is the function of peptidases?

Answer 15

Break down proteins into smaller peptides or amino acids.

Question 16

Why do all cells need the respiratory system?

Answer 16

For aerobic respiration, which provides energy.

Question 17

What is the function of the nose in the respiratory system?

Answer 17

Air enters and passes through the pharynx and larynx.

Question 18

What is the pharynx?

Answer 18

The throat; it is a passageway for air from the nose to the larynx.

Question 19

What is the larynx commonly known as?

Answer 19

The voice box.

Question 20

What is the trachea also called?

Answer 20

The windpipe.

Question 21

What is the epiglottis?

Answer 21

The structure that prevents food from entering the trachea during swallowing

Question 22

What keeps the trachea open for airflow?

Answer 22

Rings of cartilage.

Question 23

What does the trachea split into?

Answer 23

The left and right bronchi.

Question 24

What are bronchioles?

Answer 24

Smaller branches of the bronchi that lead to alveoli.

Question 25

What are alveoli?

Answer 25

Tiny air sacs at the ends of bronchioles where gas exchange occurs.

Question 26

Where does gas exchange occur in the lungs?

Answer 26

In the alveoli.

Question 27

What surrounds each alveolus to allow gas exchange?

Answer 27

Capillaries (tiny blood vessels).

Question 28

How thick are alveolar and capillary walls?

Answer 28

One cell thick

Question 29

What happens during inhalation?

Answer 29

Oxygen-rich air is brought into the alveoli.

Question 30

What is the oxygen level in blood entering the capillaries around the alveoli?

Answer 30

Low in oxygen and high in carbon dioxide.

Question 31

Why does oxygen diffuse from the alveoli into the capillaries?

Answer 31

Because there's more oxygen in the alveoli than in the blood.

Question 32

Why does carbon dioxide diffuse from the capillaries into the alveoli?

Answer 32

Because there's more CO₂ in the blood than in the alveoli.

Question 33

What type of transport is gas exchange in the lungs?

Answer 33

Passive transport by diffusion.

Question 33

What protein in red blood cells binds oxygen?

Answer 33

Hemoglobin

Question 34

How is oxygen transported through the body?

Answer 34

By binding to hemoglobin in red blood cells.

Question 35

What happens to carbon dioxide after it diffuses into the alveoli?

Answer 35

It is expelled from the body during exhalation.

Question 36

What is the role of red blood cells in gas exchange?

Answer 36

They carry oxygen from the lungs to body cells and return with carbon dioxide.

Question 37

What happens to the oxygen once it reaches body cells?

Answer 37

It is used in cellular respiration to produce energy.

Question 38

What happens to carbon dioxide produced by body cells?

Answer 38

It travels in the blood to the lungs to be exhaled.