AP Inter 2nd Year Zoology Important Questions Chapter 1(b) Breathing and Exchange of Gases

Students get through AP Inter 2nd Year Zoology Important Questions Lesson 1(b) Breathing and Exchange of Gases which are most likely to be asked in the exam.

AP Inter 2nd Year Zoology Important Questions Lesson 1(b) Breathing and Exchange of Gases

Very Short Answer Questions

Question 1.
Define vital capacity. What is its significance?
Answer:

1. Vital Capacity: It is the maximum volume of air, a person can’breathe in after ‘forced expiration’.
2. It includes expiratory tidal volume, expiration reserve volume and inspiratory reserve volume. Thus, VC = TV + ERV+ IRV
3. Significance: VC helps in the diagnosis of underlying lung diseases.

Question 2.
What is the volume of air remaining in lungs after a normal expiration?
Answer:
The volume of air remaining in lungs after a normal expiration is called functional residual capacity (FRC). FRC = ERV + RV

Question 3.
Diffusion of oxygen occurs in the alveolar region only and not in the other parts of respiratory system. How do you justify the statement?
Answer:

1. Alveoli are made up of single-cell layered epithelium which is provided with blood capillaries.
   So it is the respiratory area part where diffusion takes place.
2. Where as the trachea, bronchi and bronchioles have multilayered walls without a capillary network. So these tubes are only air-conducting parts where diffusion does not occur.

Question 4.
What is the effect of pCO₂ on oxygen transport?
Answer:

1. A rise in pCO₂ decreases the affinity of haemoglobin for oxygen.
2. A fall in pCO₂ increases affinity of haemoglobin for oxygen

Question 5.
What happens to the respiratory process in a man going up a hill?
Answer:

1. As altitude increases the pO₂ in the atmosphere decreases.
2. When a man goes up a hill he gets less oxygen with every breath.
3. The rate of respiration increases in response to decrease in the oxygen content in the blood.
4. Simultaneously the rate of heart beat increases to increase the supply of oxygen to blood.

Question 6.
What is Tidal volume? Find out the Tidal volume (approximate value) in a healthy human. In an hour.
Answer:

1. Tidal volume: It is the volume of air inspired or expired during normal inspiration or expiration.
2. It is about 500mh
3. For a minute, it is about 6000 ml to 8000ml; For an hour, it is about 360000 to 480000 ml.

Question 7.
Define the oxyhaemoglobin dissociation curve. Can you suggest any reason for its sigmoidal pattern?
Answer:

1. Oxyhaemoglobin dissociation curve is obtained when the percentage Saturation of haemoglobin with O₂ is plotted against the pO₂.
2. At normal conditions this curve is sigmoid and normal.
3. By increasing the concentration of CO₂, the curve shifts towards right side.
4. By decreasing concentration CO₂ the curve shifts towards left side. In this way the graph forms sigmoidal pattern.

Question 8.
What are conchae? [TS MAY-22]
Answer:

1. Conchae (turbinals) are three spirally twisted bones in the respiratory part of nasal chamber.
2. They regulate the temperature of inhaled air.

Question 9.
What is meant by chloride shift? [AP MAR-16]
Answer:
Chloride Shift: The exchange of chloride and bicarbonate ions between RBC and plasma at the tissues is called chloride shift (Hamburger’s phenomenon).

Question 10.
Mention any two occupational respiratory disorders and their causes in human beings.
Answer:
Occupational respiratory hazards: In certain industries harmful substances are disbursed in air. Long-time exposure to such air leads to pulmonary disorders.

1. Asbestosis: Exposure to asbestos particles causes asbestosis.
2. Black Lung disease: It is found in coal mine workers who inhale coal dust. Other disorders are silicosis (mining), and siderosis (iron).

Question 11.
Name the muscles that help in normal breathing movements.
Answer:
The muscles that help normal breathing movements: [TS MAY-22] [AP MAY-22]

1. External intercostal muscles.
2. Phrenic muscles of the diaphragm.

Question 12.
Draw a diagram of the oxyhaemoglobin dissociation curve.
Answer:

Short Answer Questions

Question 1.
Explain the process of inspiration and expiration under normal conditions.
[TS MAY-22] [ TS MAR-15]
Answer:
Inspiration:

1. Intake of atmospheric air into the lungs is called Inspiration.
2. It is an active process. It takes place by the contraction of the muscles of the diaphragm.
   This makes the diaphragm flat and increases thoracic volume in anteroposterior axis.
3. The contraction of external intercostal muscles raise the ribs sideways and increases the thoracic volume in the dorsoventral axis.
4. When the ribs and diaphragm are drawn out they pull the pleural membrane attached to lungs.
5. Then the pressure inside the lungs decreases than that of the atmosphere..

Expiration:

1. Sending out air from lungs is called expiration.
2. It is a passive process. The external intercostal muscles and diaphragm muscles relax.
3. It reduces the thoracic volume and thereby the pulmonary volume. Then the volume of the thoracic cavity is reduced.
4. The air is forced out through air passages.

Question 2.
What are the major transport mechanisms for CO₂? Explain. [AP MAR-19] [TS MAR 17]
Answer:
Transport Mechanism of CO₂:
CO₂ is transported to lungs in three different ways.

1. 7% as carbonic acid
2. About 20-25% as carbamino compound
3. About 70% as bicarbonates.

1) As carbonic acid: 7% of CO₂ combines with H₂O to form carbonic acid. It is transported in a dissolved state through plasma to lungs where it is dissociated into water and CO₂.
CO₂ + H₂O → H₂CO₃.

2) As Carbamino compound: About 20-25% of CO₂ combines with free amino group of. haemoglobin and forms carbamino haemoglobin. It is a reversible reaction.
Hb – NH₂ + CO₂ <=> Hb – NHCOO^– + H⁺

3) As Bicarbonates: About 70% of CO₂ combines with water to form H₂CO₃ in the presence of carbonic anhydrase. Carbonic anhydrase is an enzyme present in RBC and also minute quantity in plasma. In RBC, the carbonic acid dissociates into HCO₃ + H⁺.

4) At the alveolar site where pCO₂ is low, the reaction proceeds in the opposite direction, leading to the formation of CO₂ and H₂O.

5) Thus CO₂ is mostly trapped as bicarbonate at the tissues and transported to the alveoli, where it is released out as CO₂.

Question 3.
How is respiratory movements regulated in man?
Answer:
Regulation of respiratory movements:
Except the forced inhalation and forced exhalation, the respiratory movements are involuntary’. The regulation of respiration is under the control of the following:

1. Respiratory rhythm centre of medulla oblongata of the brain (RRC).
2. Pneumotoaxic centre of pons of cerebellum (brain stem)
3. The chemosensitive area close to respiratory rhythm centre.
4. Receptors present inside of aortic arch and carotid arteries.
5. Respiratory rhythm centre is mainly responsible for respiratory movements.
6. Pneumotaxic centre send signals to RRC to alter the respiratory rate when necessary.
7. Chemosensitive area is sensitive to CO₂ and H ions. It sends signals to RRC when CO₂ and H ions are more in blood. Then RRC increases respiratory rate to remove the CO₂ and H⁺.
8. There are chemo receptors inside aorta and carotid arteries which are sensitive to CO₂ and H⁺.
9. They send signals to RRC when CO₂ & IT are more in blood. So that necessary action is taken.

Question 4.
Distinguish between (a) IRV and ERV (b) Inspiratory capacity and expiratory capacity (c) Vital capacity and Total lung capacity.
Answer:
a) Inspiratory reserve volume (IRV): It is the maximum volume of air that can be inhaled during forced breathing, in addition to tidal volume. It is about 2500 ml to 3000 ml.

Expiratory reserve volume (ERV): It is the maximum volume of air exhaled during forced breathing in addition to tidal volume. It is about 1000 ml to 1100 ml

b) Inspiratory Capacity: The total volume of air, a person can inhale after normal expiration. It is the total of tidal volume and inspiratory reserve volume. It is about 3000 ml to 3500 ml.
Expiratory Capacity: The total volume of air a person can exhale after normal expiration. It is total of tidal volume and expiratory reserve volume. It is about 1100 ml to 1600 ml.

c) Vital Capacity: It is the maximum volume of air a person can breathe in after forced expiration.
VC=TV+IRV+ERV

d) Total lung capacity: It is the total volume of air in the lungs after forceful inspiration. It is total of vital capacity and residual volume.
TLC = VC + RV

Question 5.
Describe disorders of the respiratory system.
[AP,TS MAY-22] [AP MAR-15,16,17,20] [TS MAR-16,19] [ TS MAY-17]
Answer:
Disorders of the Respiratory system:
A) Asthma
B) Bronchitis
C) Emphysema
D) Pneumonia.
E) Occupational disorders

A) Asthma: Asthma is a difficulty in breathing caused due to inflammation of bronchi and bronchioles.The symptoms are wheezing, coughing, chest tightness and shortness of breath.

B) Bronchitis: It is the inflammation of bronchi with increased production of mucus.
The symptoms are chronic cough w ith thick mucus and phlem.

C) Emphysema: It is a type of chronic obstructive pulmonary disease. It is a progressive disease. The lining of alveoli are damaged beyond repair. Small air pockets develop in the lungs and trap the air. Smoking is the major cause of the disease. People feel shortness of breath.

D) Pneumonia: It is the infection of lungs by streptococcus pneumonia. Further infection takes place by virus, fungi, protozoans and mycoplasmas.

The symptoms are inflammation of lungs, and accumulation of watery mucus in alveoli. Asthma, bronchitis and emphysema are chronic obstructive pulmonary diseases [COPDS]

E) Occupational disorders:
Long time exposure to certain industries causes various types of diseases. They are

1. Asbestosis to workers in Asbestos industry.
2. Silicosis to mining workers and workers in quarries.
3. Siderosis to workers of steel and iron industries.
4. Black-lung disease to workers in coal mines.

Long Answer Questions

Question 1.
Describe the respiratory system in man.
Answer:
i) Respiratory system: Respiratory organs of man are lungs and its accessory tubes. The system has air conducting part and respiratory part. Air conducting part consists of the following:
a) External nostrils
b) Nasal chambers.
c) Nasopharynx
d) Larynx
e) Trachea
f) Bronchi and Bronchioles

a) External Nostrils: They are a pair of openings at the tip of the nose above upper lip. They lead into nasal chambers.

b) Nasal Chambers: They are present above palate. The two chambers are separated by nasal septum. Each chamber has three parts.

1. Vestibular part which has hair and sebaceous glands.
2. Respiratory part: It has 3 spirally twisted bony plates called conchae (turbinals). This part conditions the temperature of air.
3. Olfactory part: It is lined by sensory olfactory epithelium.

c) Nasopharynx: It is present above the soft palate. Nasal chambers open in nasopharynx through a pair of internal nostrils.

d) Larynx: The larynx is the voice box supported by 9 cartilages. Thyroid, cricoid and epiglottis are unpaired cartilages comiculate, arytenoid and cuneiform cartilages are paired.

Epiglottis is a thin cartilage that covers the glottis and prevents the entry of food particles or water. Vocal cords are yellow elastic fibres that extend between thyroid and arytenoid cartilages. The narrow space between the vocal cards is rema glottidis.

Adam’s apple is a projection on the ventral part of thyroid cartilage.

e) Trachea: It is a straight tube supported by ‘C’ shaped cartilages (hyaline). The rings are incomplete dorsally. Pseudostratified ciliated epithelium lines the trachea internally.

I) Bronchi and Bronchioles: The trachea divides into two primary bronchi at the level of 5th thoracic vertebra.

• Each primary bronchus divides into secondary bronchi which again.divide into tertiary bronchi.
• Each tertiary bronchus divides into primary, secondary, tertiary, terminal and respiratory bronchioles in a sequence.
• The respiratory bronchiole ends in a cluster of alveolar ducts that open into alveoli.
• The entire arrangement look like an inverted tree.

II) Respiratory part: It consists of alveolar ducts and alveoli where exchange of gases takes place. Lungs: They occupy most of the thoracic cavity. They are covered by two pleural membranes. There is pleural fluid between the two pleural membranes which prevents friction while breathing. The inner membrane is attached to the outer surface of lungs. The outer membrane is attached to the inner surface of thoracic case.

The thoracic cavity is an air tight chamber. So any change in volume of th oracic cavity is reflected in lungs. The lungs look like spongy sacs.

Question 2.
Write an essay on the transport of oxygen and carbon dioxide by blood.
Answer:
Transport of gases: Oxygen and carbon dioxide are transported by blood.

Oxygen transport: Oxygen is transported from lungs to the tissues mainly by RBC (97%) and 3% by plasma in a dissolved state.

Transport by RBC: RBC contains haemoglobin. A single molecule of haemoglobin can carry four molecules of oxygen. Oxygen is attached to haemoglobin in alveoli due to high partial pressure of O₂ to form oxyhaemoglobin. PCO₂ is low, pH is high and temperature is low in a alveoli. This process is called oxygenation.

Hb + 4O₂ ⇆ Hb(O₂)₄
At the tissues oxygen partial pressure is low. PCO₂ is high and pH is low and temperature is high in these conditions oxyhaemoglobin dissociates into oxygen and haemoglobin.

A sigmoid curve is obtained when percentage saturation of haemoglobin is plotted against PO₂. This curve is called oxyhaemoglobin dissociation curve.

When PO₂ is high, PCO₂ is low, PH is high and temperature is low as in alveoli the curve is sigmoid and saturation is upto 97%

When the PCO₂ is high or pH and PO₂ are low or temperature high as in tissue the curve swings to right.
Haemoglobin carries always 70% oxygen i.e., only 25-27% oxygen is dissociated in tissues. The effect of PCO₂ and pH on oxyhaemoglobin dissociation is called Bohr effect. Transport of CO₂: CO₂ is transported in three ways.

1. 7% in dissolved state.
2. About 20-25% as carbamino compound.
3. About 70% as bicarbonates.

1) In dissolved state: CO₂ combine with H₂O to form H₂CO₃ and is transported in plasma.
CO₂ + H₂O → H₂CO₃

2) Carbamino compounds: At tissue CO₂ combines with amino group of haemoglobin to form carbamino haemoglobin. It is a reversible reaction.
Hb-NH₂ + CO₂ ⇆ Hb-NHCOO^– + H⁺.
In alveoli CO₂ is released.

3) As Bicarbonates: About 70% of CO₂ is transported as sodium bicarbonate in plasma.
Chloride shift: There is the enzyme carbonic anhydrase in RBC. In the presence of the enzyme CO₂ combines H₂O to form H₂CO₃.
H₂CO₃ dissociates into HCO₃^– and H⁺ ions.
To maintain electrical balance HCO₃^– ions diffuse into plasma.
Chloride ions present in plasma diffuse into RBC.
H⁺ combine with haemoglobin to form HHb.
This process is called chloride shift or Hamburger’s phenomenon.
In alveoli due to high PO₂.
The Cl ions diffuse into plasma and HCO₃^– ions into RBC where they combine with H⁺ ions released from H Hb to form H₂CO₃.
H₂CO₃ dissociates into H₂0 and CO₂. CO₂ goes into alveoli.

Multiple Choice Questions

Question 1.
Inhalation and exhalation are under the control of
1. Lungs
2. Naso-pharynx
3. Medulla oblongata
4. Cerebellum
Answer:
3. Medulla oblongata

Question 2.
In birds, exchange of gases taken place even during expiration due to the presence of
1. Air sacs
2. Alveoli
3. Flight muscles
4. Pneumatic bones
Answer:
1. Air sacs

Question 3.
Aerobic respiration
1. Yields less energy
2. Occurs in the absence of oxygen
3. Yields more energy
4. Causes incomplete breakdown of organic molecules
Answer:
3. Yields more energy

Question 4.
The respiratory organs of the larvae of amphibians are
1. Gills
2. Special lungs
3. Air sacs
4. Tracheae
Answer:
1. Gills

Question 5.
The pair of internal nostrils is located above the
1. Soft palate
2. Hard palate
3. Nasopharynx
4. Oropharynx
Answer:
1. Soft palate

Question 6.
A cartilaginous box which helps in sound production in hunians is
1. Larynx
2. Syrinx
3. Glottis
4. Pharynx
Answer:
1. Larynx

Question 7.
Adam’s apple is the mid ventral prominence
1. Arytenoids cartilage
2. Thyroid cartilage
3. Cricoid cartilage
4. Comiculate cartilage
Answer:
2. Thyroid cartilage

Question 8.
The lungs are covered by
1. Pericardial membrane
2. Two pleural membranes
3. Diaphragm
4. Mediastinum
Answer:
2. Two pleural membranes

Question 9.
The place in between the pleural membranes is occupied by
1. Pericardial fluid
2. Air
3. Vacuum
4. Pleural fluid
Answer:
4. Pleural fluid

Question 10.
The process in which atmospheric air with 21% of O₂ is drawn in and alveolar air rich in CO₂ is sent out is called
1. Transport of gases
2. Diffusion of gases
3. Pulmonary ventilation
4. Cellular respiration
Answer:
3. Pulmonary ventilation

Question 11.
Respiratory gases are transported by blood between
1. Lungs and tissues
2. Trachea and Alveoli
3. Bronchioles and Alveoli
4. Alveoli and Bronchi
Answer:
1. Lungs and tissues

Question 12.
The volume of air involve in breathing movements is estimated by
1. Spirometer
2. Barometer
3. Speedometer
4. Hygrometer
Answer:
1. Spirometer

Question 13.
Approximately the volume of air inhaled or exhaled per minute by a healthy man
1. 500 to 600 ml
2. 2500 to 3000 ml
3. 6000 to 8000 ml
4. 1100 to 1200 ml
Answer:
3. 6000 to 8000 ml

Question 14.
The primary sites of exchange of gases are
1. Trachea
2. Bronchi
3. Alveoli
4. Bronchioles
Answer:
3. Alveoli

Question 15.
About 70% of carbon dioxide is transported by the hemoglobin in the form of
1. Oxyhaemoglobin
2. Bicarbonate
3. Carbonic acid
4. Carbamino haemoglobin
Answer:
2. Bicarbonate

Question 16.
7% of carbon dioxide is transported in a dissolved state through
1. Plasma of the blood
2. RBC
3. Haemoglobin
4. B lood vessels
Answer:
1. Plasma of the blood

Question 17.
The enzyme-which facilitates the transportation of CO₂ in the form of bicarbonate is
1. Carboxylase
2. Carbonic dehydrogenase
3. Dehydrogenase
4. Carbonic anhydrase
Answer:
4. Carbonic anhydrase

Question 18.
In a healthy human, each haemoglobin molecule can carry a maximum of how many molecules of O₂?
1. Two
2. Eight
3. Four
4. Twelve
Answer:
3. Four

Question 19.
The muscles of the diaphragm are called
1. Internal intercoastal muscles
2. Phrenic muscles
3. External intercoastal muscles
4. Lateral abdominal muscles
Answer:
2. Phrenic muscles

Question 20.
Black-lung disease is caused due to
1. Accumulation of mucus in alveoli
2. Inhalation of coal dust
3. Deposition of iron particles in lungs
4. Smoking of tobacco
Answer:
2. Inhalation of coal dust

Question 21.
Anaerobic respiration is found in
1. Earthworm
2. Cockroach
3. Tapeworm
4. Sea Urchin
Answer:
3. Tapeworm

Question 22.
The disease in which blood does not deliver adequate O₂ to the tissues is called
1. Anaemia
2. Anorexia
3. Hypoxia
4. Hypopnea
Answer:
1. Anaemia

Question 23.
During hibernation, frog respires by
1. Only the lungs
2. Only the skin
3. only the buccal cavity
4. Lungs and skin
Answer:
2. Only the skin

Question 24.
In muscles, anaerobic respiration results’ in the formation of product from pyruvic acid is
1. Lactic acid
2. Alcohol
3. Acetyl-CoA
4. Acetaldehyde
Answer:
1. Lactic acid

Question 25.
Dissociation curve shifts to the right when
1. CO₂ concentration decreases
2. CO₂ concentration increases
3. O₂ concentration decrease
4. Cl^– concentration increases
Answer:
2. CO₂ concentration increases

Question 26.
Organs of breathing in scorpions are
1. Gills
2. Book-lungs
3. Book-Gills
4. Trachea
Answer:
2. Book-lungs

Question 27.
Voice is produced by the vibrations of vocal cords during
1. Inspiration
2. Expiration
3. Both
4. None
Answer:
2. Expiration

Question 28.
TLC =
1. IRV+TV+ERV+RV
2. IC+FRC
3. VC+RV
4. VC+FRC
Answer:
3. VC+RV

Question 29.
Arytenoid cartilage is found in
1. Hyoid
2. Sternum
3. Larynx
4. Nose
Answer:
3. Larynx

Question 30.
A right ward shift in oxyhaemoglobin dissociation curve, is not due to
1. Increase in temperature
2. Increase in 2,3 -DPG (Diphosphoglycerate)
3. Increase in pCO₂
4. Increase in pH
Answer:
4. Increase in pH

Question 31.
The respiratory organs vary in different animals due to their
1. Nutrition
2. Habitat and level of organisation
3. Excretion
4. Reproduction
Answer:
2. Habitat and level of organisation

Question 32.
About 1200 ml of air left in lungs is called
1. Tidal volume
2. Inspiratory reserve volume
3. Residual volume
4. Vital capacity
Answer:
3. Residual volume

Question 33.
Which of the following respires via moist skin, buccal cavity and lungs
1. Hydra
2. Cockroach
3. Frog
4. Starfish
Answer:
3. Frog

Question 34.
Respiratory organs of aquatic arthropods like prawn, Cray fish and lobsters are
1. lungs
2. Gills
3. Trachea
4. Body wall
Answer:
2. Gills

Question 35.
Which of the following is not included in vital capacity
1. ERV
2. TV
3. IRV
4. RV
Answer:
4. RV

Question 36.
Trachea divides into right and left
1. Secondary bronchi
2. Tertiary bronchi
3. Bronchioles
4. Primary bronchi
Answer:
4. Primary bronchi

Question 37.
In mammals, ventilation movements of lungs are governed by
1. Diaphragm and intercostal muscles
2. Diaphragm
3. Intercostal muscles
4. Muscular wall of lungs
Answer:
1. Diaphragm and intercostal muscles

Question 38.
Inspiration occurs when intrapulmonary pressure is
1. Higher than atmospheric pressure
2. Lower than atmospheric pressure
3. Equal to atmospheric pressure
4. Zero compared to atmospheric pressure
Answer:
2. Lower than atmospheric pressure

Question 39.
With which part of Hb, O₂ molecules bind
1. Haem
2. Globin
3. Both haem and globin
4. Amino group of globin
Answer:
1. Haem

Question 40.
The amount of CO₂ delivered to the alveoli by every 100mL of deoxygenated blood is
1. 6mL
2. 4mL
3. 5 mL
4. 3 mL
Answer:
2. 4mL

Question 41.
C- shaped cartilaginous rings supporting the trachea are made of
1. Fibrous cartilage
2. Elastic cartilage
3. Calcified cartilage
4. Hyaline cartilage
Answer:
4. Hyaline cartilage

Question 42.
Ventrally and laterally, the thoracic chamber is formed by
1. Diaphragm
2. Ribs and stannum respectively
3. Stannum and ribs respectively
4. Vertebral column and diaphragm respectively
Answer:
3. Stannum and ribs respectively

Question 43.
The values of pO₂ in alveoli and tissues are respectively
1. 104 mmHg and 150 mmHg
2. 45 mmHg and 0.3mmHg
3. 104 mmHg and 40 mmHg
4. 95 mmHg and 159 mmHg
Answer:
3. 104 mmHg and 40 mmHg

Question 44.
Which of the following reflex is involved to prevent excessive inflation
1. Stretch reflex
2. Hermg Brener’s reflex
3. Withdrawal reflex
4. condition reflex
Answer:
4. condition reflex

Question 45.
Chcmoreceptors present in carotid artery and aortic arch are very much sensitive to
1. Increase in pCO₂ in arterial blood
2. Increase in pCO₂ in arterial blood
3. Decrease in pO₂ in venous blood
4. Both (2) and (3)
Answer:
2. Increase in pCO₂ in arterial blood

Question 46.
The vital capacity of our lungs is :
1. Total lungs capacity minus residual volume
2. Inspiratory reserve volume plus tidal volume
3. Total lung capacity minus expiratory reserve volume
4. Inspiratory reserve volume plus expiratory reserve volume
Answer:
1. Total lungs capacity minus residual volume