Chapter 17: Breathing and Exchange of gases Flashcards
Give some examples of organisms that respire with the help of their body surface?
Lower
invertebrates like sponges, coelenterates, flatworms, etc.,
How do earth worms respire?
with the help of moist cuticle
Which vertebrate uses gills for respiration?
fishes
Where deos the nasal chamber open into?
into the pharynx
Which organ is called the sound box?
larynx
Where is the trachea found ?
it starts form the C3/C5 vertebrae to T5 vertebrae
Which part of the bronchi are supported by cartilegenous rings?
The tracheae, primary, secondary and tertiary bronchi, and initial bronchioles are supported by incomplete cartilaginous rings.
What gives rise to alveoli?
Each terminal bronchiole gives rise to a number of very thin, irregular-walled and vascularised bag-like structures called alveoli.
What covers the lungs?
the double layer pleura with a pleural fuild in between
What is the funciton of the pleural fuild?
It reduces friction on the lung-surface.
Which part of the pleura is in contact with the lungs and which part is not?
the visceral layer is in contact with the lungs
where are the partiel layer is not in contact with the lungs
Which part of the respiratory tract compreises of the conducting tract?
The part starting with the external nostrils up to the terminal bronchioles constitute the conducting part
Which part of the respiratory tract compreises of the exchange tract?
the alveoli and their ducts form the respiratory or exchange part of the respiratory system
Is the thoracic chamber air tight or not?
it is an air tight chamber
What is present in the dorsal , ventral , aterior, prosterior , lateral side of the thoracic cavity?
do it
How is the pulmonary cavity related to the thoracic cavity?
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.
What are steps of respiration?
Respiration involves the following steps:
(i) Breathing or pulmonary ventilation by which atmospheric air
is drawn in and CO2 rich alveolar air is released out.
(ii) Diffusion of gases (O2 and CO2) across alveolar membrane.
(iii) Transport of gases by the blood.
(iv) Diffusion of O2 and CO2 between blood and tissues.
(v) Utilisation of O2 by the cells for catabolic reactions and resultant
release of CO2
What are the two stages of breathing?
inspiration and expiration
What is the meaning of intra pulmonay pressure?
it is the pressure in the lungs
What do we mean when we say there is negative pressure i the lungs and what happens ?
Inspiration can occur if the pressure within the lungs (intra-pulmonary pressure) is less than the atmospheric pressure, i.e., there is a negative pressure in the lungs with respect to atmospheric pressure
What helps in making the positive and the negative pressure of hte lungs?
The diaphragm and a specialised set of muscles – external and
internal intercostals between the ribs, help in generation of such gradients.
What initiates hte process of inspiration?
the contraction of diaphragm
the contraction of the external intercoastal muscles
What heppens to the sternums , thorax and ribs when we inspire?
when we inspire :
the sternum and the ribs moves up wards
and the diaphragm does down thus increasing the volume of teh thoracic chamber
How do we increase the sterenght of inpiration and expiration?
with the addition of muscles in the abdomen
How much does an average men breathe in a minute?
12-16 times
What is the devie used for clinical assessment of pulmonary functions?
spirometer
What is do we mean by tidal volume?
Tidal Volume (TV): Volume of air inspired or
expired during a normal respiration. It is
approx. 500 mL., i.e., a healthy man can
inspire or expire approximately 6000 to 8000
mL of air per minute
What is the meaning of inspiratory reserve volume?
Inspiratory Reserve Volume (IRV):
Additional volume of air, a person can inspire
by a forcible inspiration. This averages 2500
mL to 3000 mL.
What is the meaning of expiratory reserve volume?
Expiratory Reserve Volume (ERV):
Additional volume of air, a person can expire
by a forcible expiration. This averages 1000
mL to 1100 mL.
What is the meaning of residual volume?
Residual Volume (RV): Volume of air remaining in the lungs even after a forcible expiration. This averages 1100 mL to 1200 mL.
Inspiratory Capacity (IC):
Total volume of air a person can inspire after
a normal expiration. This includes tidal volume and inspiratory reserve
volume ( TV+IRV).
Expiratory Capacity (EC):
Total volume of air a person can expire after
a normal inspiration. This includes tidal volume and expiratory reserve
volume (TV+ERV).
Functional Residual Capacity (FRC)
Volume of air that will remain in
the lungs after a normal expiration. This includes ERV+RV.
Vital Capacity (VC):
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.
Total Lung Capacity
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.
What is the meaning of partial pressure?
Pressure contributed by an individual gas in a mixture of gases is
called partial pressure and is represented as pO2 for oxygen and pCO2
What is the partial pressure of O2 and CO2 in atmospere?
159
0.3
What is the partial pressure of O2 and CO2 in the alveoli air?
104
40
What is the partial pressure of O2 and CO2 in oxygentaed blood?
95
40
What is the partial pressure of O2 and CO2 in the deoxygented blood?
40
45
Which gas CO2 or O2 can diffuse faster and by how much?
co2 can diffuse faster by 20-25 times
What are the three layers of the diffusion membrane?
the thin squamous epithelium of
alveoli, the endothelium of alveolar capillaries
and the basement substance in between
them.
In what way is the oxygen in blood transported and what is their respective percentages?
About 97 per cent of O2 is ransported by RBCs in the blood.
The remaining 3 per cent of O2 is carried
in a dissolved state through the plasma.
In what way is the carbon
dioxide in blood transported and what is their respective percentages?
Nearly 20-25 per cent of CO2 is transported by RBCs
70 per cent of it is carried as bicarbonate.
About 7 per cent of CO2 is carried in a dissolved state through plasma
What is the compound called when haemoglobin binds with the oxygen?
oxyhaemoglobin
How much oxyge molecule can a hemoglobin molecule hold?
4
What are the condiitons that boost the binding of O2 with haemoglobin?
high pO2, low pCO2, lesser H+ concentration
and lower temperature
What is the oxygen dissociaiton curve?
A sigmoid curve is obtained when percentage saturation
of haemoglobin with O2 is plotted against the
pO2. This curve is called the Oxygen
dissociation curve
When is the oxygen dissociaiton curve used?
to study the effect of pH, pCO2 and temperature on binding of O2 with Hb
What are the condiitons unfavourable for O2 binding with Hb?
low pO2, high pCO2, high H+
concentration and higher temperature
How much O2 can 100 ml of blood deliver to the tissue?
5 ml of
O2 to the tissues under normal physiological
conditions.
When is hte binding of CO2 with Hb fascillitated?
When pCO2 is high and pO2 is low as in the tissues, more binding of carbon dioxide occurs
Why does the CO2 diffuse into the RBC and the plamsa in the tissue?
At the tissue site where partial pressure of CO2 is high due to
catabolism, CO2 diffuses into blood (RBCs and plasma) and forms HCO3
–
and H+,.
Why does the diffuse out of the bood into the alveoli?
the alveolar site where pCO2 is low, 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 (
How much CO2 is delivered to the alveoli form 100 ml of deoxygenated blood ?
4 ml of CO2
Where is the respiratory rythm ceter present and what is its funciton?
in the medulla
maintain and moderate the respiratory rhythm to suit the DEMANDS OF THE BODY TISSUE
Where is the pneumotaxic region present?
the pons region of the brain called pneumotaxic centre can MODERATE the functions of the respiratory
rhythm centre.
Neural signal from this center can REDUCE the duration of inspiration and thereby alter the respiratory rate
What is the third respiratory reglator?
A chemosensitive area is situatedADJACENT TO THE RHYTHM CENTER which is highly sensitive to CO2 and HYDROGEN IONS .
Increase in these substances can activate this centre, which in turn can signal the rhythm centre to make necessary adjustments in the respiratory process by which these substances can be ELIMINATED
Which are the blood vessle that helps in regulation of the respiration?
Receptors associated with AORTIC ARCH and CAROTID ARTERY also can recognise changes in CO2 and H+ concentration and send necessary signals to the rhythm centre for remedial actions.
Is there a role of oxygen in regulation of respiraiton =
no
What is asthma?
Asthma is a difficulty in breathing causing wheezing due to inflammation
of bronchi and bronchioles
What is emphysema?
Emphysema is a 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
What is occupational respiratory disorder/
Occupational Respiratory Disorders: 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
How do those related with the stone cutting industry protect themselves from occupational respiratory disorder?
they should wear mask
Which of the following changes occur in diaphragm and intercoastal msucles when expiration of air takes place ?
1) internal coastal muscle relax and diaphragm contracts
2) external coastal muscles and diaphragm relax
3) internal coastal muscles contract and diaphragm contract
4) external intercoastal muscles and diaphragm contract
2)
What is dead space and what is the amount of air present in it?
the amount of air present in the conducting area of the respiratory tract is called dead space
150 ml per breathe
What is the approximate normal composition of alveolar air?
1) 14% oxygen, 6% carbon dioxide and 80% nitrogen
Besides RBC, blood plasma also carries O2 in solution . The percentage is ?
2-3%
61 fingertips ) A large proportion of the oxygen remains unused in the human blood aeven after its uptake by the body tissue , WHY?
acts as a reserve during muscular exercise
62 fingertips) In the tissues , high concentratio of carbon dioxide :
1) increases the affinity of haemglobin to both oxygen and hydrogen
2) increases the affinity of haemglobin to oxygen but decrease its affinity for hydrogen
3) decreases the affinity of haemglobin to oxygen and increase its affinity for hydrogen
4) decreases the affinity of haemglobin to both oxygen and hydrogen
3)
73 FINGERTIPS )Although much CO2 is carried in blood yet the blood does not become acidic, WHY ?
although muchCO2 is carried in blood yt it does not become acidic , IT IS DUE TO CO2 TRANSPORT AND BUFFERING ACTION OF BLOOD. the main buffer present inthe blood as bicarbonate
