Chapter 8: Respiratory Systems in Humans and Animals

Question 1

Exchange of gases occurs at ______ ______ of the respiratory structures.

Answer 1

• respiratory surfaces

Question 2

What are the four main adaptations of respiratory surfaces for gaseous exchange?

Answer 2

• large total surface area of the respiratory surface
• moist respiratory surface
• thin wall of the respiratory surface
• a network of blood capillaries on the respiratory surfaces

Question 3

Explain the adaptations of respiratory surfaces for gaseous exchange.

Answer 3

Large total surface area
- respiratory surfaces are branched, folded or numerous to increase the surface area
- small in size to increase the total surface to volume ratio
Moist respiratory surface
- to dissolve the gases so they can diffuse easily and rapidly across the surface
Thin wall
- one cell thick to facilitate the diffusion of gases
A network of blood capillaries
- increase the rate of diffusion and transportation of oxygen and CO2

Question 4

The respiratory structure in insect is the _____ _____ which consists of _____, tracheae, and _____.

Answer 4

• tracheal system
• spiracles
• tracheoles

Question 5

Explain spiracles.

Answer 5

• small pores through which air enters and leaves

- has valves to control the opening and closing

Question 6

Explain trachea.

Answer 6

• a network of air tubes that open to the outside through spiracles
• supported by rings of chitin to prevent it from collapsing
• branches into fine tubes to form tracheoles

Question 7

Explain tracheoles.

Answer 7

• thin and have moist walls
• surrounded by fluid to facilitate the diffusion of gases
• diffusion of gases occur directly

Question 8

Fish has four pairs of _____ covered by an _____.

Answer 8

• gills

- operculum

Question 9

What does gill consist of?

Answer 9

• gill rakers
• gill arch
• gill filament

Question 10

What is the purpose of gill rakers and gill filaments?

Answer 10

Gill rakers
- filter the water that flows through it
Gill filaments
- respiratory surface
- has many thin and flat projections called lamellae

Question 11

What are the adaptations of gill filaments gaseous exchange?

Answer 11

• numerous gill filaments and lamellae
• thin epithelial walls
• moist surface
• a network of blood capillaries
• countercurrent flow of water and blood over the gill filaments to maximize the rate of oxygen diffusion

Question 12

The respiratory structures of amphibians such as frogs are the ____ and _____.

Answer 12

• skin

- lungs

Question 13

What are the adaptations of skin for gaseous exchange ( frogs)?

Answer 13

• thin - allows gases to diffuse easily
• moist
• network of blood capillaries underneath

Question 14

What are the adaptations of lungs ( frog )?

Answer 14

• inner walls are folded to increase total surface area
• thin walls
• a layer of moisture
• a network of blood capillaries

Question 15

What are the adaptations of the alveolus for the exchange of gases ( humans )?

Answer 15

• numerous and small
• thin wall
• moist wall
• a network of blood capillaries

Question 16

What are the similarities in the respiratory structures in humans and animals?

Answer 16

• all have a large total surface area to volume ratio
• have a thin wall
• a layer of moisture

Question 17

Breathing is the process of moving air in and out of lungs to _____ the ____ supply and remove _____ _____.

Answer 17

• replenish
• oxygen
• carbon dioxide

Question 18

The breathing mechanisms in insects involve ______ and _____ of muscles in the abdomen which causes air to move in and out through the _____.

Answer 18

• contraction
• relaxation
• spiracles

Question 19

Explain inhalation and exhalation in insects.

Answer 19

Inhalation
- abdominal muscles relax - valves of spiracles open - pressure in trachea decreases - air forced into the tracheal system through the spiracles
Exhalation
- opposite of inhalation

Question 20

The breathing mechanism in fish involves the movement of the _____ and the ___ __ __ ____ to create the flow of water into the _____ cavity and out through the operculum opening.

Answer 20

• operculum
• floor of the mouth
• buccal

Question 21

Explain the inhalation and exhalation in fish.

Answer 21

Inhalation
- mouth opens - floor of buccal cavity lowers - volume in it increases as pressure decreases - high outside pressure presses operculum and closes it - water enters the mouth
Exhalation
- mouth closes - floor of buccal cavity raises - volume in it decreases as pressure increases - operculum opens - water flows through gills over the filaments - gaseous exchange occurs

Question 22

The breathing mechanism of frogs involves the _____ __ __ ____ of the ______ cavity and the ____ of the lungs.

Answer 22

• movement of the floor
• buccopharyngeal
• elasticity

Question 23

Explain the inhalation and exhalation in frogs.

Answer 23

When the mouth and glottis are closed, the floor of the buccopharyngeal cavity is lowered. Air pressure in the mouth cavity decreased caused the air from outside enters the nostrils into the buccopharyngeal cavity.
When the glottis is opened, the nostrils are closed while the floor of buccopharyngeal cavity is raised.
Air pressure inside the mouth cavity increased caused the air inside the buccopharyngeal cavity enters the lungs and gaseous exchange occurs. When the lungs contracted, air is expelled out from the lungs. Some air is expelled through nostrils while some air mixed with the air inside the buccopharyngeal cavity

Question 24

The breathing mechanism in humans involves the action of _____ muscles and _____ muscles.

Answer 24

• intercostal

- diaphragm

Question 25

Explain the inhalation and exhalation in humans.

Answer 25

Inhalation - external intercostal contracts as internal intercostal relax - ribcage moves upwards and outwards - diaphragm muscles contract and flattens - increase the volume of the thoracic cavity - air pressure in the thoracic cavity decreases - air in the atmosphere enters the lungs Exhalation - opposite of inhalation

Question 26

Gaseous exchange occurs by the process of _____ and involves _____ and carbon dioxide.

Answer 26

- diffusion | - oxygen

Question 27

Explain the gas exchange at the alveolus.

Answer 27

- inhaled air contains more O2 and less CO2 - hence the partial pressure of O2 is higher in the alveolus compared to in the blood capillaries - O2 diffuses out from the alveolus into the blood capillaries down the partial pressure gradient of oxygen - during respiration, CO2 produced - partial pressure of CO2 is higher in the blood capillaries than in the alveolus which causes it diffuses out into the alveolus

Question 28

Explain the partial pressure for the air in the alveolus, blood from the alveolus to the pulmonary vein, and the blood from the pulmonary artery entering the alveolus.

Answer 28

Air in the alveolus - high ( O2 ) low ( CO2 ) Blood from the alveolus to the pulmonary vein - high ( O2 ) low ( CO2 ) Blood from the pulmonary artery entering the alveolus - high ( CO2 ) low ( O2 )

Question 29

In the blood capillaries surrounding the alveolus, oxygen diffuses into the red blood cells and combines with ______ to form ________.

Answer 29

- haemoglobin | - oxyhaemoglobin

Question 30

Explain the diffusion of oxygen from the blood capillary into the body cells.

Answer 30

- oxyhaemoglobin is not stable - it breaks down as the cells lack oxygen - oxygen is released and diffuses into the plasma of the blood capillaries - the partial pressure of oxygen is higher than in the body cells - hence, it diffuses out of the blood capillary into the body cells

Question 31

Explain the diffusion of carbon dioxide from body cells into the blood capillary.

Answer 31

- cellular respiration releases CO2 - body cells contain a high concentration of CO2 - hence the partial pressure of CO2 in the body cells is higher - CO2 diffuses out of the body cells into the blood capillary

Question 32

Explain the transport of CO2 from the body cells to the alveolus.

Answer 32

- 70% of CO2 is carried through plasma in the form of bicarbonate ions - some diffuse into the RBC and combine with haemoglobin to form carbaminohaemoglobin - some dissolve to form carbonic acid - at the alveolus, bicarbonate ions, carbaminohaemoglobin, and carbonic acid break down to release CO2 into the plasma - higher partial pressure of CO2 causes it to diffuse into the alveolus and be expelled during exhalation

Question 33

What are some issues related to the human respiratory system?

Answer 33

- Chronic Obstructive Pulmonary Disease ( COPD ) includes asthma, chronic bronchitis, and emphysema

Question 34

Explain COPD.

Answer 34

- a chronic respiratory disease that obstructs airflow to the lungs and interferes with normal breathing - dust, air pollutants, and irritants enter the lungs - stimulates the secretion of viscous mucus by the goblet cells - inhibits movement of cilia of the epithelial lining - carcinogenic substances accumulate in bronchioles - results in inflammation - elasticity is lost in the alveolus

Question 35

What are chronic bronchitis, asthma, and emphysema?

Answer 35

Chronic bronchitis - inflamed bronchial tubes produce a lot of mucus Asthma - wall of the bronchiole swells and thickens Emphysema - breaking down of the alveoli wall which reduces the total surface area

Question 36

List out the symptoms of the diseases.

Answer 36

``` Chronic bronchitis - shortness of breath - cough with phlegm - wheezing Asthma - difficulty in breathing - chest tightness - wheezing Emphysema - exhausted - shortness of breath ```