A) $$P_{O_2}$$ in lung is less than $$P_{O_2}$$ in blood ; $$P_{CO_2}$$ in lung is greater than $$P_{CO_2}$$ in blood.

B) $$P_{O_2}$$ in lung is greater than $$P_{O_2}$$ in blood; $$P_{CO_2}$$ in lung is less than $$P_{CO_2}$$ in blood.

C) $$P_{O_2}$$ in lung is greater than $$P_{O_2}$$ $$P_{CO_2}$$ in blood; $$P_{CO_2}$$ in lung is greater than $$P_{CO_2}$$ in blood.

D) $$P_{O_2}$$ in lung is less than $$P_{O_2}$$ in blood; $$P_{CO_2}$$ in lung is less than $$P_{CO_2}$$ in blood.

A) $$P_{O_2}$$ in blood is greater than $$P_{O_2}$$ in tissues; $$P_{CO_2}$$ in blood is greater than $$P_{CO_2}$$ in tissues.

B) $$P_{O_2}$$ in blood is less than $$P_{O_2}$$ in tissues; $$P_{CO_2}$$ in blood is greater than $$P_{CO_2}$$ in tissues.

C) $$P_{O_2}$$ in blood is less than $$P_{O_2}$$ in tissues; $$P_{CO_2}$$ in blood is less than $$P_{CO_2}$$ in tissues.

D) $$P_{O_2}$$ in blood is greater than $$P_{O_2}$$ in tissues; $$P_{CO_2}$$ in blood is less than $$P_{CO_2}$$ in tissues.

A) controlling body fluid pH

B) regulating blood pressure

C) regulating blood volume

D) all of the above

A) glottis

B) epiglottis

C) larynx

D) trachea

A) macrophages in the pulmonary lymph nodes

B) cytotoxic T-lymphocytes

C) alveolar macrophages

D) NK cells in the elastic tissues of the lungs

A) pneumonia

B) a pulmonary embolism

C) acute bronchitis

D) an immune response

A) Oxygen cannot diffuse through the membrane and so must be actively transported

B) Oxygen cannot diffuse through the membrane and so must be actively transported

C) Respiratory membrane is the only barrier between the blood and the inhaled gases within each alveolus.

D) Carbon dioxide diffuses across the membrane from the blood into the alveolar lumen.

A) vital capacity

B) expiratory reserve volume

C) residual volume

D) tidal volume

A) alveolar macrophages and the alveolar cell membrane

B) alveolar cell membrane and its basement membrane

C) alveolar cell membrane, capillary membrane and fused basement membranes

D) alveolar cell membrane and capillary membrane

A) i: as oxyhaemoglobin; ii: as bicarbonate ions

B) i: dissolved in the plasma; ii: as carbaminohaemoglobin

C) i: as oxyhaemoglobin; ii: as carbaminohaemoglobin

D) i: in association with haemoglobin; ii: as carbon dioxide, dissolved in the plasma

A) the partial pressure of oxygen in the lungs and in the blood

B) the partial pressure of oxygen in the lungs only

C) the partial pressure of oxygen and carbon dioxide in the blood

D) the partial pressure of all gases in the atmosphere and blood

A) inspiratory reserve volume

B) expiratory reserve volume

C) total lung capacity

D) vital capacity

A) rising oxygen concentration

B) rising carbon dioxide concentration

C) falling oxygen concentration

D) falling carbon dioxide concentration

A) It allows diving seals to store twice as much oxygen in their blood as the average human of similar size.

B) It allows diving seals to store a considerable amount of oxygenated blood in their spleens.

C) It allows diving seals to store a considerable amount of oxygen in their muscles.

D) It allows seals to switch from cellular respiration to fermentation after the oxygen in muscle cells has been depleted.

A) a decrease in pH and a decrease in the PO2

B) a decrease in pH and an increase in the PO2

C) an increase in pH and an increase in the PO2

D) an increase in pH and a decrease in the PO2

A) A decrease in the pH of the cerebrospinal fluid triggers the brain's breathing control centres, which stimulate diaphragm and rib muscle contractions.

B) The pH of the cerebrospinal fluid also increases and is detected by O2 sensors in arteries near the heart.

C) The O2 level automatically increases.

D) The medulla, moderated by the pons, signals the heart muscle to beat harder, bringing in more O2.

A) vital capacity

B) tidal volume

C) residual capacity

D) ventilation volume

A) Gills are not as efficient as lungs in picking up oxygen.

B) Protecting gas-exchange surfaces from desiccation is difficult in terrestrial environments.

C) Air has higher oxygen content than water, so gills were no longer necessary.

D) Gills work only in aquatic animals; lungs work only in terrestrial animals.

A) be dry and covered with hair

B) be moist and glandular

C) be thick and moist

D) be thin and moist

Type 1 pneumocyte

Type 2 pneumocyte

Dust cell

Clara cell

Simple squamous

Ciliated cuboidal

Simple cuboidal

Ciliated columnar

Diaphragm

External intercostals and external obliques

External obliques

Diaphragm and external intercostals

pleural fluid

ciliated mucus

surfactant

mucus

a decrease in chest volume

an increase in chest volume

an increase in lung capacity

no change in air volume

1,2,3,4

2,3,1,4

2,1,3,4

4,2,3,1

mucus

surfactant

water

cartilage

They are thin, single layer of permeable cells in the alveoli walls

They secrete a chemical called surfactant

They cover about 5% of the alveoli surface

They are not directly involved with gas exchange

The surfactant that they secrete increases surface tension

They prevent the sides of alveoli from sticking together

They help gases to dissolve

They are found on the inner surface of alveoli

The diffusion distance between alveoli and blood increases

Alveoli become larger

Cilia are damaged so less bacteria can enter the lungs

Alveoli cannot recoil as easily so it is more difficult to exhale

Type I pneumocytes

Type II pneumocytes

Internal intercostal muscle fibres

External intercostal muscle fibres

They have muscles which pump air in and out regularly

Their membranes are more permeable to gases than water

A constant blood supply flows through them

A dense network of capillaries surrounds them

So that oxygen and CO2 can get close enough to diffuse between the wall of the capillaries

So the blood can flow into the alveoli.

So the pneumocytes can travel through the alveoli.

So that nutrients can get close enough to diffuse.

I

II

III

IV

cilia

alveolar macrophages

mucous glands and goblet cells

Goblet cells

epiglottis

trachea

septum

glottis

bronchi

capillaries

larynx

alveoli

windpipe

larynx

nasal cavity

nasal septum

partial pressure

even pressure

osmotic pressure

alveolar epithelial cells, capillary endothelial cells and their basement membranes

fluid and surfactant alveolar epithelial cells, capillary endothelial cells and their basement membranes

visceral pleura, parietal pleura and serous fluid.

ciliated epithelial cells, mucus cells and secreted mucus

Epiglottis

Trachea

Bronchi

Alveoli

nerve impulses

rings of cartilage

fine bones

smooth muscle contractions

parietal and visceral membranes.

parietal and visceral meninges

pleura

peritoneum

to trap inhaled particles not removed by the nasal cavity

to secrete a mucus layer onto the epithelium

to move mucus and trapped particles up the bronchial tree

to secrete surfactant that decreases water surface tension

Structure that separates food and air passageway

It has walls made of cartilage

It has walls made of bone

It has walls made of muscle

Intercostal

Diaphragm

Epiglottis

Larynx

Pharynx

Larynx

Esophagus

Epiglottis

Systemic tissues, arterial blood, alveolar air

Systemic tissues, alveolar air, arterial blood

Blood in aorta, atmospheric air, systemic tissues

Atmospheric air, blood in aorta, systemic tissues