Ch 14 New

Question 1

Mechanisms of breathing vary among different groups of animals
depending mainly on their …………… and …………………………….

Answer 1

habitats and levels of organisation.

Question 2

Lower invertebrates like sponges, coelenterates, flatworms, etc., exchange O2
with CO2 by ………………………………………….

Answer 2

simple diffusion over their entire body surface.

Question 3

Earthworms use their……

Answer 3

moist cuticle

Question 4

Insects have a…………………………to transport atmospheric air within the body.

Answer 4

network of tubes (tracheal tubes)

Question 5

Special vascularized structures called gills (branchial respiration) are used by most of the
………………………………….

Answer 5

aquatic arthropods and molluscs

Question 6

Vascularized bags called lungs (pulmonary respiration) are used by the ……………. for the exchange of gases.

Answer 6

terrestrial forms

Question 7

Among vertebrates, fishes use…………

whereas amphibians, reptiles, birds and mammals respire through ……….

Answer 7

gills
lungs

Question 8

Amphibians like frogs can respire through their………

Answer 8

moist skin (cutaneous respiration)

Question 9

We have a pair of external nostrils opening out above the upper lips.
It leads to a nasal chamber through the nasal passage. The nasal
chamber opens into the pharynx, a portion of which is the common
passage for food and air. The pharynx opens through the larynx region
into the trachea.

Question 10

Pharynx is ……

Answer 10

a portion of which is the common passage for food and air.

Question 11

The pharynx opens through

Answer 11

the larynx region into the trachea.

Question 12

Larynx is a cartilaginous box which helps in

Answer 12

sound production and hence called the sound box.

Question 13

During swallowing ………….. can be covered by a thin elastic cartilaginous flap called …………….to prevent the entry of food into the larynx.

Answer 13

glottis
epiglottis

Question 14

Trachea is a straight tube extending up to the,……………… which divides at the level of ………….. into a right and left primary bronchi.

Answer 14

mid-thoracic cavity
5th thoracic vertebra

Question 15

Trachea is a straight tube extending up to the mid-thoracic cavity, which divides at the level of 5th thoracic vertebra into…………………………….

Answer 15

a right and left primary bronchi

Question 16

Each bronchi undergoes repeated divisions to form the ……………

Answer 16

secondary and tertiary bronchi and bronchioles ending up in very thin terminal bronchioles.

Question 17

The tracheae, primary, secondary and tertiary bronchi, and initial
bronchioles are supported by ……………….

Answer 17

incomplete cartilaginous rings.

Question 18

Each terminal bronchiole gives rise to a number of very……………..

Answer 18

thin, irregular-walled and vascularised bag-like structures called alveoli.

Question 19

Alveoli….

Answer 19

very thin, irregular-walled and vascularized bag-like structures (where exchange of gas occurs)

Question 20

The branching network of …….., …………. and ……………comprise the lungs.

Answer 20

bronchi, bronchioles and alveoli

Question 21

We have two lungs which are covered by a double layered…………,
with pleural fluid between them. It reduces friction on the lung-surface.

Answer 21

pleura

Question 22

The outer pleural membrane is in close contact with the ……… whereas the inner pleural membrane is in contact with the………………….

Answer 22

thoracic lining
lung surface

Question 23

The part starting with the external nostrils up to the terminal
bronchioles constitute the ………………. whereas the alveoli and their
ducts form the ………………………….of the respiratory system.

Answer 23

conducting part
respiratory or exchange part

Question 24

The conducting part transports the……………., ………………., …………… and also……………….

Answer 24

atmospheric air to the alveoli,
clears it from foreign particles,
humidifies
brings the air to body temperature.

Question 25

Exchange part is the site of actual diffusion of O2 and CO2 between blood and atmospheric air.

Question 26

Exchange part is.................................

Answer 26

the site of actual diffusion of O2 and CO2 between blood and atmospheric air.

Question 27

The lungs are situated in the ............................which is anatomically an air-tight chamber.

Answer 27

thoracic chamber

Question 28

The thoracic chamber is formed dorsally by the.................., ventrally by the........... , laterally by the........... and on the lower side by the ....................

Answer 28

vertebral column (dorsally) sternum (ventrally) ribs (laterally) dome-shaped diaphragm (lower side)

Question 29

The anatomical setup of lungs in thorax is such that any change in the volume of the thoracic cavity will be reflected in the lung (pulmonary) cavity. Such an arrangement is essential for breathing, as we cannot directly alter the pulmonary volume.

Question 30

Respiration involves the following steps:

Answer 30

1 Breathing or pulmonary ventilation by which atmospheric air is drawn in and CO2 rich alveolar air is released out. 2 Diffusion of gases (O2 and CO2) across alveolar membrane. 3 Transport of gases by the blood. 4 Diffusion of O2 and CO2 between blood and tissues. 5 Utilization of O2 by the cells for catabolic reactions and resultant release of CO2

Question 31

Breathing involves two stages :

Answer 31

1. Inspiration during which atmospheric air is drawn in 2. Expiration by which the alveolar air is released out.

Question 32

The movement of air into and out of the lungs is carried out by creating a pressure gradient between the .......... and ..................

Answer 32

lungs and the atmosphere

Question 33

Inspiration can occur if the pressure within the lungs (intra-pulmonary pressure) is .............. than the atmospheric pressure, i.e., there is a ..................... pressure in the lungs with respect to atmospheric pressure.

Answer 33

less negative

Question 34

Expiration takes place when the intra-pulmonary pressure is ............. than the atmospheric pressure.

Answer 34

higher

Question 35

The .........and a specialized set of muscles .................................... between the ribs, help in generation of such gradients.

Answer 35

diaphragm external and internal intercostals

Question 36

Inspiration is initiated by the ................................. which increases the volume of thoracic chamber in the antero-posterior axis. (attach figures)

Answer 36

contraction of diaphragm

Question 37

The contraction of external inter-costal muscles lifts up the ribs and the sternum causing an increase in the volume of the thoracic chamber in the dorso-ventral axis.

Answer 37

As (external inter-costal muscles) : contracts which lifts ribs and sternum that increases volume of thoracic chamber in the dorso-ventral axis.

Question 38

The overall increase in the thoracic volume causes a similar increase in pulmonary volume. An increase in pulmonary volume decreases the intra-pulmonary pressure to less than the atmospheric pressure which forces the air from outside to move into the lungs, i.e., inspiration (Figure 14.2a).

Question 39

Relaxation of the diaphragm and the inter-costal muscles returns the diaphragm and sternum to their normal positions and reduce the thoracic volume and thereby the pulmonary volume. This leads to an increase in intra-pulmonary pressure to slightly above the atmospheric pressure causing the expulsion of air from the lungs, i.e., expiration (Figure 14.2b).

Question 40

We have the ability to increase the strength of inspiration and expiration with the help of additional muscles in the.......

Answer 40

abdomen

Question 41

On an average, a healthy human breathes: ................

Answer 41

12-16 times/minute

Question 42

The volume of air involved in breathing movements can be estimated by:

Answer 42

spirometer

Question 43

The volume of air involved in breathing movements can be estimated by using a spirometer which helps in ................

Answer 43

clinical assessment of pulmonary functions.

Question 44

Tidal Volume (TV):

Answer 44

Volume of air inspired or expired during a normal respiration. It is approx. 500 mL A healthy man can inspire or expire approximately 6000 to 8000 mL of air per minute.

Question 45

Tidal Volume (TV):

Answer 45

Volume of air inspired or expired during a normal respiration.

Question 46

How much is Tidal Volume (TV) in mL?

Answer 46

It is approx. 500 mL

Question 47

A healthy man can inspire or expire approximately

Answer 47

6000 to 8000 mL of air per minute.

Question 48

Inspiratory Reserve Volume (IRV):

Answer 48

Additional volume of air, a person can inspire by a forcible inspiration. This averages 2500 mL to 3000 mL

Question 49

Expiratory Reserve Volume (ERV):

Answer 49

Additional volume of air, a person can expire by a forcible expiration. This averages 1000 mL to 1100 mL

Question 50

Residual Volume (RV):

Answer 50

Volume of air remaining in the lungs even after a forcible expiration. This averages 1100 mL to 1200 mL. By adding up a few respiratory volumes described above, one can derive various pulmonary capacities, which can be used in clinical diagnosis.

Question 51

Inspiratory Capacity (IC):

Answer 51

Total volume of air a person can inspire after a normal expiration. This includes tidal volume and inspiratory reserve volume ( TV+IRV).

Question 52

Expiratory Capacity (EC):

Answer 52

Total volume of air a person can expire after a normal inspiration. This includes tidal volume and expiratory reserve volume (TV+ERV).

Question 53

Functional Residual Capacity (FRC):

Answer 53

Volume of air that will remain in the lungs after a normal expiration. This includes ERV+RV.

Question 54

Vital Capacity (VC):

Answer 54

The maximum volume of air a person can breathe in after a forced expiration. This includes ERV, TV and IRV or the maximum volume of air a person can breathe out after a forced inspiration

Question 55

Total Lung Capacity (TLC):

Answer 55

Total volume of air accommodated in the lungs at the end of a forced inspiration. This includes RV, ERV, TV and IRV or vital capacity + residual volume.

Question 56

The primary sites of exchange of gases.

Answer 56

Alveoli

Question 57

Exchange of gases also occur between ......... and ...............

Answer 57

blood and tissues.

Question 58

Alveoli are the primary sites of exchange of gases. Exchange of gases also occur between blood and tissues. O2 and CO2 are exchanged in these sites by simple diffusion mainly based on ............................

Answer 58

pressure/concentration gradient

Question 59

Solubility of the gases as well as the thickness of the membranes involved in diffusion are also some important factors that can affect the rate of diffusion

Question 60

Pressure contributed by an individual gas in a mixture of gases is called ..................... and is represented as pO2 for oxygen and pCO2 for carbon dioxide.

Answer 60

partial pressure

Question 61

table 14.1

Question 62

Table

Question 63

Table

Question 64

Table

Question 65

The diffusion membrane is made up of three major layers (Figure 14.4) namely, ..... The basement substance is composed of a .....

Answer 65

1. the thin squamous epithelium of alveoli, 2. the endothelium of alveolar capillaries and the 3. basement substance (thin basement membrane supporting the 1. squamous epithelium 2. basement membrane surrounding the single layer endothelial cells of capillaries) in between them.

Question 66

However, its total thickness (talking about basement substance) is much less than a........ Therefore, all the factors in our body are favorable for diffusion of O2 from alveoli to tissues and that of CO2 from tissues to alveoli.

Answer 66

millimeter

Question 67

Blood is the medium of transport for O2 and CO2. About 97 per cent of O2 is transported by...... The remaining 3 per cent of O2 is carried in a dissolved state through the....

Answer 67

RBCs in the blood. plasma.

Question 68

Nearly 20-25 per cent of CO2 is transported by....... 70 per cent of it is carried as..... About 7 per cent of CO2 is carried in a dissolved state through.......

Answer 68

RBCs bicarbonate plasma.

Question 69

Hemoglobin

Answer 69

Red colored iron containing pigment present in the RBCs.

Question 70

O2 can bind with hemoglobin in a reversible manner to form .......

Answer 70

oxyhemoglobin.

Question 71

Each hemoglobin molecule can carry a maximum of ........ molecules of O2.

Answer 71

four

Question 72

Binding of oxygen with hemoglobin is primarily related to .....

Answer 72

partial pressure of O2.

Question 73

................ , ................ and temperature are the other factors which can interfere with this binding. (Binding of oxygen with hemoglobin)

Answer 73

1. Partial pressure of CO2 2. Hydrogen ion concentration and 3. Temperature

Question 74

A sigmoid curve is obtained when percentage saturation of hemoglobin with O2 is plotted against the pO2. This curve is called the......... (Figure 14.5) and is highly useful in studying the effect of factors like pCO2, H+ concentration, etc., on binding of O2 with hemoglobin.

Answer 74

Oxygen dissociation curve

Question 75

In the alveoli, where there is ........, ..........., .........., and ............. and ............. , the factors are all favorable for the formation of oxyhemoglobin,

Answer 75

1. high pO2 2. low pCO2 3. lesser H+ concentration and 4. lower temperature

Question 76

In the tissues, where .........., ............. , ............ and ............ exist, the conditions are favorable for dissociation of oxygen from the oxyhemoglobin

Answer 76

1. low pO2 2. high pCO2 3. higher H+ concentration 4. higher temperature

Question 77

O2 gets bound to hemoglobin in the ............ and gets dissociated at the

Answer 77

lung surface tissues.

Question 78

Every 100 ml of oxygenated blood can deliver around ....... of O2 to the tissues under normal physiological conditions.

Answer 78

5 ml

Question 79

When pCO2 is ........ and pO2 is ........ as in the tissues, more binding of carbon dioxide occurs

Answer 79

high low

Question 80

CO2 is carried by hemoglobin as ............ (about 20-25 per cent). This binding is related to the partial pressure of CO2. pO2 is a major factor which could affect this binding

Answer 80

carbamino-hemoglobin

Question 81

When the pCO2 is ....... and pO2 is ....... as in the alveoli, dissociation of CO2 from carbamino-hemoglobin takes place CO2 which is bound to hemoglobin from the tissues is delivered at the alveoli

Answer 81

low high

Question 82

RBCs contain a very high concentration of the enzyme, ............ and minute quantities of the same is present in the plasma too. This enzyme facilitates the following reaction in both directions. (add the picture)

Answer 82

carbonic anhydrase

Question 83

At the tissue site where partial pressure of CO2 is ....... due to catabolism, CO2 diffuses into blood (RBCs and plasma) and forms HCO3 – and H+,.

Answer 83

high

Question 84

At the alveolar site where pCO2 is ........., the reaction proceeds in the opposite direction leading to the formation of CO2 and H2O. Thus, CO2 trapped as bicarbonate at the tissue level and transported to the alveoli is released out as CO2 (Figure 14.4).

Answer 84

low

Question 85

Every 100 ml of deoxygenated blood delivers approximately ........ of CO2 to the alveoli.

Answer 85

4 ml

Question 86

Human beings have a significant ability to maintain and moderate the respiratory rhythm to suit the demands of the body tissues. This is done by the neural system. A specialized center present in the ........ region of the brain called ........... is primarily responsible for this regulation.

Answer 86

medulla respiratory rhythm center

Question 87

Another center present in the ....... region of the brain called ........... can moderate the functions of the respiratory rhythm center. Neural signal from this center can reduce the duration of ............... and thereby alter the respiratory rate.

Answer 87

pons pneumatic center inspiration

Question 88

A chemo sensitive area is situated adjacent to the rhythm centre which is highly sensitive to ........ and ......... Increase in these substances can activate this center, which in turn can signal the rhythm center to make necessary adjustments in the respiratory process by which these substances can be eliminated.

Answer 88

CO2 hydrogen ions.

Question 89

Receptors associated with ........ and ......... also can recognize changes in CO2 and H+ concentration and send necessary signals to the rhythm center for remedial actions

Answer 89

aortic arch carotid artery

Question 90

The role of ......... in the regulation of respiratory rhythm is quite insignificant.

Answer 90

oxygen

Question 91

Asthma

Answer 91

Difficulty in breathing causing wheezing due to inflammation of bronchi and bronchioles.

Question 92

Emphysema

Answer 92

Chronic disorder in which alveolar walls are damaged due to which respiratory surface is decreased. One of the major causes of this is cigarette smoking.

Question 93

Occupational Respiratory Disorders

Answer 93

In certain industries, especially those involving grinding or stone-breaking, so much dust is produced that the defense mechanism of the body cannot fully cope with the situation. Long exposure can give rise to inflammation leading to fibrosis (proliferation of fibrous tissues) and thus causing serious lung damage. Workers in such industries should wear protective masks.