Chapter 11: Human Biology (Respiratory System)

Question 1

larynx (3)

Answer 1

• contains the vocal cords
• a passageway for air
• prevents food from entering lower respiratory tract

Question 2

trachea (2)

Answer 2

• tube with cartilaginous rings that allow air to pass to the bronchus
• cleans, warms, and moistens air

Question 3

bronchi (2)

Answer 3

• branch off the trachea leading to the bronchioles

- passage of air to bronchioles

Question 4

bronchioles (2)

Answer 4

• smaller, numerous branches leading to the alveoli responsible for passage of air to each lung
• also warms, cleans, and moistens air

Question 5

alveoli (2)

Answer 5

• thin walled microscopic air sacs in the lungs

- responsible for gas exchange between air and blood vessels

Question 6

diaphragm

Answer 6

contracts and moves downward to increase chest cavity space so lungs may expand

Question 7

ribs

Answer 7

protects the lungs like armour

Question 8

pleural membranes

Answer 8

lubrication during inspiration and expiration (pleural membrane covers both lungs and another covers the internal chest wall and diaphragm, both layers provide lubrication so they may slide over each other when the lungs inflate and deflate during respiration)

Question 9

thoracic cavity (2)

Answer 9

• contains lungs, thymus, trachea, heart, esophagus

- provides protection

Question 10

cilia

• lines what part of your respiratory tract
• function

Answer 10

• trachea

- filters pollution and particles

Question 11

mucous

Answer 11

moistens and warms air, improving diffusion rate

Question 12

alveoli

• shape, shape importance, function
• traits and their importance (2)
• stretch receptors

Answer 12

• spherical in shape, increasing the surface area and thus the gas exchange
• vast capillary network on the surface of alveoli and the thin walls of alveoli increases the diffusion efficiency
• coated with a pulmonary surfactant that reduces surface tension, preventing alveoli from closing and inhibiting gas exchange
• stretch receptors of alveoli send inhibitory nerve impulses to the respiratory centre, temporarily preventing the nerve centre from impacting breathing

Question 13

mechanics of the inhalation process (6)

Answer 13

• rib cage moves up and then out
• diaphragm contracts and moves down
• volume in lungs increases
• air pressure in lung/thoracic cavity decreases
• air moves in
• active process

Question 14

mechanics of the exhalation process (6)

Answer 14

• rib cage moves down and then in
• diaphragm relaxes and moves up
• volume in lungs decreases
• increase in air pressure in lung/thoracic cavity
• air moves out
• passive process

Question 15

• roles of carbon dioxide and hydrogen ions in stimulating the breathing centre in the medulla oblongata
• why can the respiratory centre detect CO2 and H+ levels

Answer 15

• when either carbon dioxide or hydrogen ion levels increase, the respiratory centre, located in the medulla oblongata, increases the rate and depth of breathing
• the respiratory centre contains cells that are sensitive to the carbon dioxide and hydrogen ion levels in blood

Question 16

external respiration location, conditions, and properties (3)

Answer 16

• location: lungs
• conditions: low temperature and high pH
• due to these conditions: Hemoglobin loses its affinity for carbon dioxide and hydrogen and gains an affinity for oxygen; carbon dioxide can now diffuse out of plasma and then into the lungs; oxygen now enters the blood

Question 17

internal respiration location, conditions, and properties (3)

Answer 17

• location: tissues
• conditions: high temperature and low pH
• due to these conditions: Hemoglobin loses its affinity for oxygen and oxygen can now diffuse into the tissues; hemoglobin gains an affinity for carbon dioxide and hydrogen ions; 10% of the carbon dioxide that diffuses out of tissues and into the blood form carbaminohemoglobin, the rest form carbonic acid with the help of carbonic anhydrase; then dissociates into hydrogen ions and bicarbonate ions, hemoglobin picks up the excess hydrogen ions to form reduced hemoglobin

Question 18

oxyhemoglobin

Answer 18

carries oxygen to the tissues

Question 19

carbaminohemoglobin

Answer 19

carries carbon dioxide back to the lungs

Question 20

reduced hemoglobin

Answer 20

carries excess hydrogen ion in the blood

Question 21

bicarbonate ions

Answer 21

• carries CO2 in the plasma

- most of the CO2 in plasma is carried this way