Chapter 8: Respiratory System in Humans and Animals

Question 1

Adaptation of respiratory structure

Answer 1

• large ratio of total surface area per volume (TSA/V) for gases exchange
• one cell thick wall for diffusion
• moist surface for dissolve
• network of blood capillaries for delivery

Question 2

respiratory surface in insect

Answer 2

tracheole

Question 3

function of air sacs in insects

Answer 3

filled with air to speed up the delivery of respiratory gases during active state

Question 4

Breathing mechanism of frog

Answer 4

Inhalation,

• air is breath in through nostril
• mouth and glottis is closed
• floor of buccopharyngeal lowered to increase the cavity
• air pressure in buccopharyngeal cavity decrease
• air is draws into buccopharyngeal cavity through nostril
• glottis open and nostril close
• buccopharyngeal floor is raised
• high pressure in buccopharyngeal cavity push the force to enter the lungs

Exhalation,

• lungs contract to expel the air out of the lungs
• aid by abdominal pressure and elasticity of lungs
• some of the air is expelled through nostril
• the rest is mixed with the air in buccopharyngeal cavity

Question 5

Breathing mechanism of fish

Answer 5

Inhalation,

• mouth open and floor of buccal cavity is lowered
• operculum opening is closed and opercular cavity is enlarged
• pressure in buccal cavity is reduced
• water with dissolve oxygen entered the buccal cavity through mouth

Exhalation,

• mouth closed and floor of buccal cavity is raised
• water flows through the lamellae
• gases exchange occur via diffusion
• opercular muscle relax cause operculum cavity to reduce
• volume of buccal cavity decrease
• pressure in buccal cavity higher than outside
• water is force to flow out through operculum opening

Question 6

Breathing mechanism of human

Answer 6

Inhalation,

• external intercoastal muscle contract and internal intercoastal muscle relax
• ribcage move upwards and outwards
• diaphragm muscle contract
• diaphragm move downwards become flat and horizontal
• volume of thorax cavity increase
• higher pressure in outside force air into lungs

Exhalation,

• internal intercoastal muscle contract and external intercoastal muscle relax
• ribcage move downwards and inwards
• diaphragm muscle relax
• diaphragm curve upwards and form a dome
• volume of thorax cavity decrease
• high pressure push the air out of the lungs

Question 7

gases exchange in humans

Answer 7

• Blood enter the lungs through pulmonary artery has low partial pressure of O2 and high partial pressure of CO2
• blood in lung capillaries has higher partial pressure of CO2 compared to alveolus
• CO2 diffuse from lung capillaries into alveolus
• blood in lung capillaries has lower partial pressure of O2 compared to alveolus
• O2 diffuse from alveolus into lung capillaries
• O2 combine with haemoglobin in erythrocyte to form oxyhaemoglobin
• blood leaves the lungs through pulmonary vein has high partial pressure of O2 and low partial pressure of CO2
• cellular respiration produce CO2
• blood in tissue capillaries has lower partial pressure of CO2 compared to cells
• CO2 diffuse from cells into tissue capillaries and transported back to lungs
• cellular respiration require oxygen
• blood in tissue capillaries has higher partial pressure of O2 compared to cells
• oxyhaemoglobin in tissue capillaries break down to release oxygen into cells

Question 8

3 method of transportation of CO2

Answer 8

• 70% bicarbonate ions
• 23% carbaminohaemoglobin
• 7% carbonic acid

Question 9

transport of CO2 from body cells to tissue capillaries

Answer 9

1. CO2 + H2O –> H2CO3
   - carbon dioxide combine with water to form carbonic acid
   - catalyst by carbonic anhydrase enzyme
2. H2CO3 –> HCO3- + H+
   - carbonic acid break down into bicarbonate ions and hydrogen ions
3. bicarbonate ions diffuse into blood plasma and transported to lungs

Question 10

transport of CO2 from tissue capillaries to lung capillaries

Answer 10

1. bicarbonate ions diffuse from blood plasma back to erythrocyte
2. HCO3- + H+ –> H2CO3
   - bicarbonate ions combine with hydrogen ions to form carbonic acid
3. H2CO3 –> CO2 + H2O
   - carbonic acid break down into carbon dioxide and water
4. CO2 diffuse through lung capillaries into alveolus and expelled during exhalation

Question 11

3 COPD

Answer 11

Chronic Obstructive Pulmonary Disease

• asthma
• bronchitis
• emphysema

Question 12

explain asthma

Answer 12

• bronchiole swollen and thicken
• opening tube of bronchiole smaller
• air passage become smaller
• difficulty of breathing

Question 13

explain brontchitis

Answer 13

• bronchiole swollen, inflammed and blocked
• secrete large amount of mucus
• difficult of breathing
• continuous coughing’
• damage cilium cause mucus unable to secrete

Question 14

explain emphysema

Answer 14

• alveolus lose elasticity and increase in size
• wall of alveolus damage
• decrease total surface area of alveolus decrease
• gases exchange less efficient

Question 15

mechanism of fish

Answer 15

Counter-current mechanism

• blood in blood capillaries flow in opposite direction with the flow of water
• this ensure that the red blood cells in blood capillaries always meet fresher water with higher concentration of dissolved oxygen
• steeper oxygen concentration gradient cause diffusion and absorption of dissolved oxygen by red blood cells