Breathing 1

Question 1

explain the structure of the nasal chamber

Answer 1

I pair of external nostrils ( dirhynous condition)
Nasal chambers are seperated by hyaline cartilage
The naterior part of th e nasal chamber is formed by the nasal vestibule( formed by the invagination of skin during embryonic development), it bears hair sebaceous glands that help in the removal of foreign particles.

The posterior part is made of 3 bones called nasal conchae. at several places these bones have outgrowths called turbinals to make passage long and spiral, to lengthen passage for air flow ( humidify air, bring to room temp, clean air)

Question 2

expain the stricture of pharynx

Answer 2

The nasal chamber opens into the pharyns via nasopharynx.
the pharynx is made up of 3 parts:
i) nasopharynx from nasal chamber
(ii) Oropharync from mouth
iii) laryngeopharynx/hypopharynx present bfr the larynx

opening of food pipe is c/a gullet
opening of the larynx is caled glottis

Question 3

explain the structure of larynx

Answer 3

Larynx is the sound producing organ in which two types of vocal cords are present
(i) False
(ii) True
False vocal cords provide moisture to the true vocal cords. Whereas true vocal cords are
helpful in phonation (Sound production)

Question 4

what is trachealis muscle

Answer 4

it is a voluntary muscle that is prevent on the dorsal side of the trachea. it helps in dilating the trachea during forceful respiration

Question 5

explain the lungs

Answer 5

The pleural layer has 2 membranes
i) outer/parietal pleura- close with the thoracic lining(ribs)
ii)inner/visceral pleura- close with lung surface/ alveoli

The left lung is bilobed and has a notch called the cardiac notch where the heart is placed. The two lobes of the long is seperated by an oblique fissure.

The space between the 2 lungs where the heart is placed is called as the mediastinum.

The right lung is trilobed demarcates by the oblique fissure and horizontal fissure.

Mammalian lungs are solid and spongy without muscles so power of self contraction and self
relaxation is not present in mammalian lungs.

Question 6

describe diaphragm

Answer 6

The diaphragm is a dome shaped muscle, it is a chracteristic feature of mammals.
also c/a as phrenic muscle
Phrenic nerve is for diaphragm contraction.
It is the muscular structure which separate thoracic cavity from abdominal cavity.
m/o radial muscles

helpful forbreathing, parturition, micturition and defacation (b/c helps in creating pressure diff)

Question 7

describe alveoli

Answer 7

Alveoli are structural and functional units of
lungs.
 Alveoli consist of two types of cells called
pneumocytes.
 Pneumocytes I are smaller cells and helps in
gaseous exchange whereas pneumocytes II are
larger cells which secrete a phospholipid
LECITHIN.
Lecithin act as a surfactant reduces the surface tension of alveoli and keep alveoli always remain
open for efficient gaseous exchange. Deficiency of lecithin in alveoli causes respiratory distress
syndrome.
 On the outer side of alveoli yellow fibrous connective tissue is present. The total number of
alveoli present in both the lungs of man is 300 million.

Question 8

which parts form the thoracic chamber/ thoracic cage?

Answer 8

airtight chamber:
- dorsally- vertebral column
- ventrally sternum
- laterally ribs
- anterior clavicle
- posterior diaphragm

Question 9

what are the intercostla muscles

Answer 9

Spaces between two pair of ribs are called
intercoastal spaces. Whereas muscles in these
spaces are called intercoastal muscles. There
are two types of intercoastal muscles
(a) External intercoastal muscles (EICM)
(b) Internal intercoastal muscles (IICM)

Question 10

explain the time taken per breathing cycle

Answer 10

i) inspiration- active - 2s
ii) expiration-passive- 3s

for 1 breathing cycle= 5s
no of cycles per minute= 12-16 breaths per minute

Question 11

explain the mechanism of breathing

Answer 11

i) inspiration
- diaphragm- contracts
- eicm- contracts
thoracic volume increases, pulmonary volume increases, so pressure decreases

ii) exspiration
- diaphragm relax
- eicm- relax
thoracic volume decreaes, pulm. volume, decreasesm so pressure increases

iii) forcible exppiration’/abdominal breathing
- diaphragm -relax
eicm- relax
iicm- contrac
abdominal muscle- contract

so forcible expiration is active while just expiration is a passive process.

Answer 12

Abdominal breathing due to diaphragm mainly.
 In fever breathing rate increases.
 When CO2 concentration increases in blood breathing rate becomes faster.
 Breathing rate in infants is greater than adults.
 Eupnoea :- It is the state of normal breathing. In man rate of normal breathing is 12-16 per
minute. In infants rate of breathing is 44 per minute. Rate of breathing is slowest while
sleeping.
 Bradypnoea or Hyponoea :- It is the state of slow breathing.
 Rapid breath or hypernoea :- It is the state of fast breathing.
 Apnoea - It is the state of stoppage of breathing temporarily.
 Dyspnoea - It is the state of painful breathing due to pleurisy.
 Asphyxia - It is the state of suffocation due to high CO2 concentration or low O2 concentration.

Question 13

what are expiratory muscles

Answer 13

abdominal muscles and iicm

Question 14

what is dead space

Answer 14

air present in the conducting part of the respiratory system is called as dead space air.
150ml of air

Question 15

which instrument can measure respiratory volume

Answer 15

spirometer
it cant measure residual volume
most of the residual volume occurs in alveoli

Question 16

explain the binding of oxygen

Answer 16

Hb4+O2—->Hb4O8
atAlveoli
atTissues

1 gm of haemoglobin transports 1.34 ml of oxygen. 100 ml (1 dL) of blood contains
normally 15 gm of haemoglobin, so 100 ml blood transports approximately 20 ml of
oxygen.

thereis approx. % 5Lof blood in the human body. 1L of oxygen is carried in one full cycle.

In a conducting cycle blood gives its 25% O2 to tissues.

Question 17

oxygen dissociation curve

Answer 17

 A graph is plotted between O2 concentration
and percentage saturation of haemoglobin
with this curve is called oxygen dissociation
curve.
 Dissociation curve is sigmoid shape.
 This curve is highly useful in
studying the effect of factors like,
H+
concentration, temperature on
binding of O2 with Haemoglobin.
 Shift to left means that increase in
affinity between O2 and Hb.
 Shift to Right means that decrease in
affinity between O2 and Hb and
dissociation of oxyhaemoglobin.

% saturation of Hb= no of molecules of o2 binded to Hb/ no of moelcules of o2 that can combine with Hb x 100%

Question 18

explain bohr effect and haldane effect

Answer 18

bohr effect= right shift= tissue level
- breakdown of HbO2
- metabolism increases
- temperature increase
- H+ ion conc increase, pH decrease
- pCO2 increase
- bisphosphoglycerate increases

haldane effect= left shift= lung/alveoli
- formation of HbO2
- metabolism decreeases
-temperature decreases
- h+ ion conc decreaes pH increases
- pCO2 decrease
- BPGA decrease

Question 19

what is
(i) methemoglobin
(ii) oxyhaemoglobin
(iii) carboxyhaemoglobin
(iv) carbaminohaemoglobin
(v) myoglobin

Answer 19

(i) Haemoglobin generally has iron in +2 oxidn state. If iron atom is present as +3 oxidn state, it is called methemoglobin. o2 doesnot bind to methemoglobin. oxidised haemoglobin

(ii) oxygen+ Hb
(iii) CO + Hb
(iv) CO2+ Hb
(v) oxygen storage molecule in muscle cell

Question 20

explain co2 transport

Answer 20

 The majority of bicarbonate ions (HCO3
the plasma along a concentration gradient. In the plasma HCO3
–) formed within the erythrocytes diffuse out into
– combine with Na+ and
form Sodium bicarbonate (NaHCO3). Nearly 70% CO2 transported by plasma as NaHCO3
form.
 In response of HCO3
–, chloride ions (Cl–) diffuse from plasma into the erythrocytes to
maintain the ionic balance. Thus, electrochemical neutrality is maintained. This is called
Chloride shift or Hamburger Phenomenon. The chloride ions react with with the K+ present in the rbc to form KCl. ( to prevent accumulation of Cl-)

The H+ presnt in the RBC reacts with Haemoglobin to form haemgolobinic acid. This acid is a weak acid. It behaves as a buffer and maintains the pH of blood.

Question 21

what stimulates the dissociation of carbaminohaemoglobin.

Answer 21

This dissociation is stimulated by oxyhaemoglobin. This CO2 freed from blood goes into
atmosphere. The effect of oxyhaemoglobin on the dissociation of these compounds is
known as Haldane effect. In this reaction oxyhaemoglobin acts like a strong acid i.e, it
frees H+ in the medium.

Question 22

define the folllowing

Answer 22

Anoxia - It is the lack of O2 supply to tissues.
 Hypocapnoea - It is the state of reduced CO2 concentration in blood.
 Hypercapnoea - It is the state of increased CO2 concentration in blood.
 Acapnia : Stoppage of breathing due to very low CO2 in blood.
 Hypoxia : O2 deficiency in body tissues.
 Reasons of hypoxia :
(a) Anaemia
(b) Low O2 in atmosphare
(c) High CO2 in atmosphere
 Anaemic hypoxia (CO poisoning) : CO binds haemoglobin 200 to 300 times faster than
oxygen to form stable carboxyhaemoglobin.

Question 23

(i) amt of co2directly dissolved in plasa
(ii) amt of co2 present in plasma in dissolved state

Answer 23

(i)7%
(ii)77%

Question 24

affinity of haemoglobin complex

Answer 24

co- 200/300 times more affinity than o2
co2- 20/25 times more affinity than o2

Question 25

what are the 2 types of neurons present in RCC

Answer 25

(i) Dorsal Respiratory group (DRG)- eicm, diaphragm- normal inspiration
(ii) Ventral respiratory group (VRG)-iicm, eicm, diaphragm, abdominal muscles- forceful inspiration/ forceful expiration

Question 26

what is
(i) bronchitis
(ii) rhinitis
(iii) asthma

Answer 26

(i)Bronchitis- disorder of bronchi where thr is regular swelling and itching of bronchi, charcaterissed by regular coughing

(ii) inflammation of nasal tract

(iii) it involves the spasms of diaphragm, in response to allergens

Question 27

What is the chemical nature of oxyhaemoglobin

Answer 27

Acidic

Question 28

Why is blood basic

Answer 28

Because if it is acidic the bidding of oxygen with Hb reduces

Question 29

What is the origin of the respiratory system

Answer 29

Endo mesoderm

Question 30

Explain the pressures of oxygen and carbon dioxide

Answer 30

The affinity for Hb for co2 is much more than its affinity for o2.

So the partial pressures of co2 are only around 40-45 mm Hg. But for oxygen a larger pressure difference is needed to we take 105 mmHg and 90mmHg

Question 31

How do we know if a child dies after birth or before birth

Answer 31

If the child died after birth jt will have residual air in lung
If it died in the womb it will not have residual air