Question 1. Describe mechanics of respiration. (or) Muscles of respiration.
Answer:
Respiration:
- It is the process by which oxygen is taken in and carbon dioxide is taken out.
- Each respiratory cycle consists of 2 phases.
1. Inspiration:
- It is an active process.
- During inspiration, thorax is enlarge by.
Read And Learn More: BDS Previous Examination Question And Answers
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- Ribs movement:
- Due to the contraction of scaleni muscles, the first pair of ribs move upwards to a more horizontal position.
- This draws manubrium sterni – upwards and forwards.
- 2nd 6th pair of ribs – upper costal series.
- They move upwards and this movement is called pump handle movement.
- It occurs due to contraction of external intercostal muscles.
- It increases anteroposterior diameter of thoracic cage.
- Central portion of these ribs move upwards and outwards and this movement is called Bucket handle movement.
- It increases transverse diameter of thorax.
- 7th-10th pair of ribs – lower costal series.
- Shows bucket handle movement.
- Increases transverse diameter of thorax.
- 11th and 12 th pair of ribs – floating ribs.
- Remain unchanged.
- Due to the contraction of scaleni muscles, the first pair of ribs move upwards to a more horizontal position.
- Diaphragmatic movements:
- Diaphragm is a dome-shaped structure with convexity facing upwards.
- During inspiration due to discharge in phrenic neurons, muscle fibers contract and central tendinuous portion is drawn downwards.
- This flattens the diaphragm and increases the vertical diameter of the thoracic cage:
- Movements of lungs.
- During inspiration, as the enlargement of thoracic cage, negative pressure is increased in thoracic cavity.
- This results in expansion of lungs.
- Ribs movement:
2. Expiration:
- It is a passive process.
- During expiration, following changes occurs.
- Contraction of anterior abdominal wall muscles.
- This increases intra-abdominal pressure.
- Lowers the ribs to normal position.
- Pushes diaphragm upwards.
- Internal intercostal muscles.
- On contraction of these muscles, the upper ribs are pull down.
Movement of lungs: - During expiration, as the thoracic cavity decreases in size, the pressure of thorax comes back to normal.
- This compresses the lung tissues.
- On contraction of these muscles, the upper ribs are pull down.
- Contraction of anterior abdominal wall muscles.
Question 2. What is surfactant? Where it is synthesized? Explain three of its important functions. (or) Surfactant.
Answer:
Surfactant:
- It is a surface acting material or agent that is responsible for lowering the surface tension of a fluid.
- It is a mixture of protein-lipid complexes made up of mainly dipalmitoyl phosphatidyl choline lipid along with other lipids and proteins and ions like calcium.
Source of synthesis:
- Surfactant is produced by.
1. Granular pneumocytes
- It is alveolar lining epithelial type II cells.
2. Clara cells or bronchiolar exocrine cells.
- They are situated in the bronchioles
surfactant Functions:
1. Reduction of surface tension:
- The surfactant reduces the surface tension in the alveoli of lungs and prevents the collapsing tendency of lungs.
Reduction of Surface Tension Mechanism:
- Phospholipid molecule in the surfactant has two portion.
- Hydrophilic portion.
- Formed by SP-A and SP-D proteins.
- Hydrophobic portion.
- This dissolves in water and lines the alveoli.
- Formed by SP-B and SP-C proteins.
- It is directed towards the alveolar air.
- Thus, surfactant spreads over the alveoli forms a layer between the fluid lining the alveoli and alveolar air and reduces surface tension in the alveoli of lungs.
- Hydrophilic portion.
2. Stabilization of the alveoli:
- Surfactant is responsible for stabilization of the alveoli.
- This helps to withstand the collapsing tendency of lungs.
3. Inflation of lungs:
- Secretion of surfactant begins from third month of intrauterine life.
- Until birth, the lungs are solid and not expanded.
- In infants, breathing occurs due to the stimulation of respiratory centers by hypoxia and hypercapnea.
- However, the lungs tends to collapse repeatedly when the infant attempts respiratory movements.
- Presence of surfactant in the alveoli prevents this collapsing of lungs.
4. Defensive function :
- Surfactant protects the lungs against infection and inflammation.
- SP-A and SP-D proteins of surfactant.
- Destroys bacteria and virus by opsonisation.
- Controls the formation of inflammatory mediators.
Question 3. Describe factors determine oxygen uptake in lung.
Answer:
Factors determining oxygen uptake in lungs:
1. Pressure gradient:
- Uptake of oxygen by the blood in the lungs in mainly favoured by oxygen pressure gradient.
- Thus, because of this pressure gradient. O2 rapidly diffuses from alveoli through the thin pulmonary and capillary endothelium into the plasma.
2. Thickness of respiratory membrane:
- Diffusion is inversely proportional to the thickness of respiratory membrane.
- In pulmonary fibrosis or edema, the thickness of respiratory membrane increases due to collection of fluid in the membrane.
- This decreases the diffusion.
3. Surface area:
- Diffusion of gases is directly proportional to the surface area of the respiratory membrane.
- During block in pulmonary capillary, the surface area of the membrane decreases.
- During exercise, surface area increases and thus diffusion of O2 also increases.
4. Solubility of gas:
- Diffusion of O2 is directly proportional to the solubility of gas.
- If the solubility of a gas is more in the fluid medium, a large number of molecules are available or diffusion.
- So, diffusion also increases.
5. Molecular weight of the gas:
- Diffusion of gas is inversely proportional to its molecular weight.
- If the molecular weight is more the density is more and diffusion is less.
6. Diffusion coefficient:
- It is defined as a constant, which is the measure of a dissolved substance diffusing through the concentration gradient.
- It reduces when the molecular size of the diffusing substance is increased.
- Thus, the smaller molecules diffuses rapidly than the large ones.
Relation between diffusion and its factors:
Question 4. Describe transport of oxygen in blood. (or) Oxygen-haemoglobin dissociation curve.
Answer:
Transport of oxygen:
- Oxygen is transported by the blood from alveoli to the tissue.
- Oxygen is transported in blood in 2 forms.
1. Dissolved form:
- Oxygen dissolves in water of plasma and is transported.
- Oxygen transported in this form is 0.3 ml per 100 ml of blood per 100 mm Hg pO2
Oxygen in Blood Significance:
- About 3% of total oxygen in blood is transported in this form.
- Oxygen is transported in this form in stress full conditions like exercise.
- It occurs due to excess demand of oxygen by the tissues.
Amount of oxygen transported:
- Arterial – 0.3 ml per 100 ml of blood.
- Venous – 0.12 ml per 100 ml of blood.
2. In combination with haemoglobin:
- Oxygen combines with haemoglobin in blood and is transported as oxyhaemoglobin.
- Each haemoglobin molecule has 4 heme groups which have an iron in ferrous form.
- Sixth valency bond of each Fe2+ combines with 2 atoms of oxygem.
- Therefore, S atoms of oxygen combines with one mole of haemoglobin.
- No oxidation reaction takes place during this combination.
Oxygen in Blood Significance:
- Maximum amount of oxygen, about 97% is transported in this form.
- Oxygen can be released from haemoglobin easily when needed.
- Haemoglobin also accepts oxygen readily when the pO2 is more and gives out oxygen when the pressure is less.
Oxygen carrying capacity of haemoglobin:
- One gram of haemoglobin carried 1.34 ml of oxygen.
- This is called oxygen carrying capacity of haemoglobin.
- 1 gram of Hb = 1.34 ml of oxygen.
- Now, normal haemoglobin content – 15 gram%.
- So, oxygen carried in this form (15 x 1.34) ml = 20.1 ml of oxygen in 100 ml of blood.
- But the 15% of haemoglobin carries only 19 ml% of oxygen.
- It is due to absence of full saturation of haemoglobin with oxygen.
- It is saturated only for about 95%.
- The oxygen carrying capacity of haemoglobin is given by oxygen haemoglobin dissociation curve.
Oxygen haemoglobin dissociation curve:
- The relationship between the partial pressure of oxygen and the percentage saturation of haemoglobin with oxygen is explained graphically by the oxygen haemoglobin dissociation curve.
- It is sigmoid shaped.
- Lower part of curve.
- Indicates dissociation of oxygen from haemoglobin.
- Upper part of curve.
- Indicates acceptance of oxygen by haemoglobin depending upon the partial pressure of oxygen.
- Lower part of curve.
Amount of oxygen transported in this form:
- Arterial blood = 19 ml per 100 ml of blood.
- Venous blood 13.88 ml per 100 ml of blood.
Question 5. Discuss factors affecting transport and diffusion of gases.
Answer:
Factors Affecting Transport:
1. Transport of oxygen:
- Amount of oxygen entering the lung.
- Adequacy of pulmonary gas exchange.
- Blood flow to the tissue.
- It is increased by following factors.
- Increase in capillary density.
- Local arteriolar dilation.
- It is increased by following factors.
- Capacity of the blood to carry O2.
- Due to splenic contraction, RBC count is increased.
- This, in turn, increases haemoglobin content.
- More the haemoglobin, more the oxygen is combined with it and carried along the blood.
2. Transport of Co2:
- Blood oxygen content.
- In tissue capillaries, blood oxygen content decreases producing deoxygenated blood.
- As the oxygen content decreases, carbon dioxide increases.
- Thus, more Co2 is transported.
- Similarly, in lung capillaries, blood oxygen content is more which decreases Co2 content of blood.
- Thus, less Co2 is transported.
- Number of RBC present in the blood.
- From plasma, the carbon dioxide enters the RBCs.
- In the RBCs, carbon dioxide combines with water to form carbonic acid.
- This carbonic acid readily dissociates into bicarbonate and hydrogen ions.
- This increased concentration of bicarbonate inside the RBC causes diffusion of bicarbonate ions through the cells membrane into the plasma.
- Thus, more the RBC, more bicarbonate ions are diffuses.
- So, more carbon dioxide is transported as bicarbonate.
- The amount of reduced Hb.
- Reduced Hb contains less O2 content and more Co2 content in blood.
- Thus, as the amount of reduced Hb increases, Co2 content also increases.
- So, more Co2 is transported.
Question 6. With the help of labelled diagram of oxygen-haemoglobin dissociation curve, explain the transport of oxygen from the lungs to the tissues. Give two factors shifting this curve to the right and significance of such shift.
Answer:
Shifting of curve towards right:
Oxygen-Haemoglobin Dissociation Curve Significance:
- Indicates dissociation of oxygen from haemoglobin.
- It signifies that as the oxygen content held by the blood decreases, it causes dissociation of oxygen.
Oxygen-Haemoglobin Dissociation Curve Effecting:
1. Partial pressure of gases:
- Decrease in partial pressure of oxygen causes this shift.
- While increases in partial pressure of carbon dioxide causes this shift.
2. Blood pH:
- Fall in blood pH occurring due to
- Increases in Co2 content.
- Increase of H ion concentration.
- Presence of any acid in blood.
- All these shifts the curve towards right.
3. Body temperature:
Increase in body temperature shifts the curve towards right.
4. 2, 3, diphophoglyceric acid (2, 3. DPG):
- 2,3 DPG competes with oxygen for the binding sites on the haemoglobin molecule.
- Thus, at a given pO2 the percentage saturation of haemoglobin with O2 will be reduced in the presence of 2, 3. DPG.
- So, the curve shifts to right.
- DPG increases during exercise and in high altitude.
Question 7. Describe nervous regulation of respiration. (or) Neural regulation of respiration. (or) Respiratory centers/ name the respiratory centers and describe their functions.
Answer:
Nervous Regulation of Respiration:
- It is brought about by.
1. Automatic control:
- Respiration is involuntary controlled by the respiratory centers.
- These respiratory centers are as follows.
2. Voluntary control:
- Respiration can be modified both in rate and/or depth at will for a specific period only.
- The pathway for such a control is via. Corticospinal tract originating from the cerebral cortex and end on spinal motor neurons.
- It innervates the respiratory group of muscles.
Regulation of inspiration:
- Inspiration is regulated by apneustic centre.
- Activation of apenustic centre causes stimulation of inspiratory centre.
- Inspiratory centre in turn sends impulses via spinal cord to the anterior horn cells.
- This results in inspiration.
Regulation of expiration:
- Inspiratory neurons from the inspiration center sends excitatory impulses to `pneumotaxic’ center.
- Pneumotaxic center sends inhibitory impulses to apenustic centre.
- During inspiration, pulmonary stretch receptors are stimulated.
- This send inhibitory impulses to apneustic centre via vagus nerve.
- Pneumataxic centre.
- Stimulates expiratory centre.
- Inhibits inspiratory centre.
- Inhibits apneustic centre.
- Thus inspiration is inhibited and expiration occurs passively.
Question 8. Define hypoxia and enumerate the different types of hypoxia. Explain changes taking place in the body during acclimatization hypoxia.
Answer:
Hypoxia Definition:
- Hypoxia is defined as reduced availability of oxygen to the tissues.
Hypoxia Types:
1. Hypoxic hypoxia:
- Occurs due to decreased oxygen content in the blood.
2. Anaemic hypoxia:
- It is inability of the blood to carry enough amount of oxygen.
3. Stagnant (ischaemic) hypoxia:
- It occurs due to decreased velocity of blood flow.
4. Histotoxic hypoxia:
- It is inability of tissues to utilize oxygen.
Changes occurring in body during Hypoxia:
1. On kidney:
- Hypoxia stimulates juxtaglomerular apparatus of kidney.
- This increases the secretion of erythropoietin.
2. On blood:
- Due to increased secretion of erythropoietin from kidney by hypoxia, red bone marrow is stimulated.
- As a result, RBC count increase with increases in haemoglobin content.
- As haemoglobin increases, oxygen carrying capacity of blood also increases.
3. On respiration:
- Hypoxia stimulates peripheral chemoreceptors.
- As a result, large amount of carbon dioxide is washed out and oxygen enters.
4. On CVS:
- Hypoxia stimulates peripheral chemoreceptors.
- This in turn stimulates.
1. Vasomotor centre.
↓
Sends acceleratory impulses to heart
↓
Causes vasoconstriction
↓
Increses heart rate.
2. Cardia vagal centre-decreases heart rate.
3. Respiratory centre-increases heart rate.
Question 9. Describe the nervous regulation of respiration. Add a note on Herring-Breurr’s reflex.
Answer:
Nervous Regulation of Respiration:
- It is brought about by
1. Automatic control:
- Respiration is involuntary controlled by the respiratory centers
- These respiratory centers are as follows:
2. Voluntary control:
- Respiration can be modifies both in rate and/or depth at will for a specific period only
- The pathway for such a control is via corticospinal tract originating from the cerebral cortex and end on spinal motor neurons
- It innervates the respiratory group of muscles
Herring-Breurr’s reflex Regulation of inspiration:
- Inspiration is regulated by apneustic center
- Activation of apneustic center causes stimulation of inspiratory center
- Inspiratory centre in turn sends impulses via spinal cord to the anterior horn cells
- This results in inspiration
Herring-Breurr’s reflex Regulation of expiration:
1. Inspiratory neurons from the inspiration center sends excitory impulses to pneumotoxic center
- Pneutoxic center sends inhibitory impulses to apneustic centre
2. During inspiration, pulmonary stretch receptors are stimulated
- This send inhibitory impulses to apneustic centre via vagus nerve
3. Pneumataxic center
- Stimulates expiratory centre
- Inhibits inspiratory centre
- Inhibits apneustic centre
- Thus inspiration is inhibited and expiration occurs passively
Herring Breuer’s Reflex:
- This reflex occur due to stimulation of stretch receptors present on lungs
- It prevents overstretching of lung muscles
During inspiration, the lungs are filled with air gets stretched
↓
This stimulates stretch receptors present on lungs
↓
These receptors send impulses through vagal nerve to respiratory centers
↓
It inhibits dorsal group neurons
↓
As a result inspiration stops and expiration occurs
- It is also known as Hering Breuer inflation reflex since it occurs due to inflation of lungs
Question 10. Respiratory muscles:
Answer:
1. Inspiratory Muscles:
- Respiratory muscles involved during inspiration are called inspiratory muscles.
- Primary inspiratory muscles:
- Muscles which change the size of thoracic cage during quiet breathing are called primary inspiratory muscles.
- Acessory inspiratory muscles:
- Muscles that act during forced respiration are called accessory inspiratory muscles.
- Primary inspiratory muscles:
2. Expiratory Muscles:
- Muscles involved in expiration are called expiratory muscles.
- Primary expiratory muscles.
- These muscles are responsible for change in size of thoracic cage during quiet breathing.
- Accessory expiratory muscles.
- These muscles help during forced respiration.
- Primary expiratory muscles.
Question 11. Outline the mechanics of respiration.
Answer:
Respiration Mechanism:
1. Respiration Inspiration:
- It is active process.
- Following changes occurs.
2. Respiration Expiration:
- It is passive process.
- It involves.
- Contraction of anterior abdominal wall muscles.
- Brings ribs to their normal position.
- Pushes diaphragm upwards.
- Contraction of internal intercostals muscles.
- Pulls the upper ribs downwards.
- Contraction of anterior abdominal wall muscles.
Question 12. Vital capacity. (or) Define vital capacity and give its normal values.
Answer:
- It is the maximum amount of air that can be expelled out forcefully after a deep respiration.
- It includes following lung volumes.
1. Inspiratory reserve volume (IRV):
- It is the maximal volume of air which can be inspired after completing a normal tidal inspiration.
Normal value:
- 2000-3300 ml.
2. Expiratory reserve volume (ERV):
- It is the maximal volume of air which can be expired after completing a normal tidal expiration.
Normal value:
- 750-1000 ml.
3. Tidal volume (TV):
- It is the volume of air breathed in or out of lungs, during quiet respiration.
Normal value:
- 500 ml.
Measurement of Vital Capacity:
- It is measured by spirometry
- Vital capacity = IRV + ERV +TV.
= 3300 + 1000+ 500 4800 ml.
Variations:
1. Physiological variations:
Sex:
- In males, it is 4.8 litres.
- In females, it is 3.2 litres.
Age:
- It decreases with age due to loss of elasticity of lungs.
Body built:
- It slightly increases in heavily built persons.
Posture:
- It is more in standing position because of.
- Decrease in venous return.
- Descend of diaphragm.
- Decrease in pulmonary blood flow.
Atheletes:
- It is more in athelets.
Pregnancy:
- It decreases in pregnancy.
2. Pathological variations:
- It is reduced in presence of respiratory diseases.
Pathological variations Advantages:
- Provides information about strength of respiratory muscles.
- Provides information about pulmonary functions.
Question 13. What are two types of dead space? How it is determined?
Answer:
Dead Space Definition:
- It is the amount of air in the respiratory passage which does not take part in exchange of gases.
Dead Space Types:
1. Anatomical dead space:
- It is the volume of air present in the `conducting zone’ of the respiratory passage.
- It exists from nose and mouth upto terminal bronchiole where exchange of gases does not take place.
2. Physiological dead space:
- It includes anatomical dead space plus volume of air in the alveoli which does not take part in exchange of gases.
- It includes.
- Air in the non-functioning alveoli.
- Air in the alveoli which do not receive adequate blood flow.
Dead Space Normal value:
- The volume of normal dead space is 150 ml.
Determination of dead space:
- The dead space is determined by single breath nitrogen washout method.
- The subject is asked to take a deep breath of pure oxygen and expire steadily into a nitrogen meter.
- The concentration of nitrogen in the expired air is recorded continuously.
- The first portion of expired air comes from upper part of respiratory tract contains only oxygen.
- The next portion of expired air comes from the alveoli containing nitrogen.
- The nitrogen concentration in expired air increases continuously.
- The graph obtained is as follows.
Question 14. Draw a normal oxygen-haemoglobin dissociation curve. Explain Borh’s effect.
Answer:
Normal oxygen haemoglobin dissociation curve:
Bohr’s Effect:
- The relationship between the partial pressure of oxygen and the percentage saturation of haemoglobin with oxygen is explained graphically by oxygen haemoglobin dissociation curve.
- This curves shifts to right due to increase in partial pressure of carbon dioxide.
- In the tissues due to continuous metabolic activities, partial pressure of carbon dioxide increases in it and partial pressure of oxygen is less.
- Due to this pressure gradient, carbon dioxide moves from tissues to blood and oxygen moves from blood to tissues.
- Due to presence of carbon dioxide in blood, affinity of haemoglobin to oxygen decreases.
- As a result, the curve shifts to right.
- Thus, Bohr’s effect is loading of carbon dioxide to blood causing dissociation of oxygen at tissue level.
Question 15. Transport of carbon dioxide.
Answer:
Carbon dioxide is transported by the blood from tissues to the alveoli in four ways.
1. As dissolved from -7%:
- Carbon dioxide diffuses into blood and dissolves in the fluid of plasma forming a simple solution and is transported.
2. As carbonic acid – negligible:
- Carbon dioxide enters the plasma and combines with water to form carbonic acid.Co2+ H2O H2CO3
- Only 0.2% is transported in this form.
3. As carbamino compounds -30%:
In plasma:
- Co2 combines with plasma proteins and forms carbomino proteins.
- It is loose bond so can be easily released
- It is reversible reaction.
In RBCs:
- Co2 combines with haemoglobin and forms carbhaemoglobin.
- It is also reversible process.
4. As bicarbonates – 63%:
- From plasma, Co2 enters the blood.
- Here, Co2 combines with water present in RBC and forms carbonic acid in the presence of carbonic anhydrase enzyme.Co2+H2O → H2CO3
- Carbonic acid is unstable compound, so it reaily dissociated into bicarbonate and hydrogen ions.H2CO3 → HCO3– + H+
- By this, concentration of bicarbonate ion increases in RBCs.
- This leads to diffusion of bicarbonate from cell into plasma. Thus, Co2 is transported in this form.
Question 16. Chemical Regulation of Respiration.
Answer:
The chemical regulation of respiration is brought about by respiratory chemoreceptors.
Chemical Regulation of Respiration Types:
- Respiratory chemoreceptors are of two types.
1. Peripheral chemoreceptors.
Chemical Regulation of Respiration Situation:
- Carotid body near the common carotid artery bifurcation.
- Aortic bodies – near the arch of aorta.
Chemical Regulation of Respiration Mechanism of action:
Stimulant reduction in partial pressure of oxygen
↓
Stimulates chemoreceptors.
↓
This send impulses to inspiratory center via aortic and sinus nerves.
↓
Causes stimulation of inspiratory center.
2. Central chemoreceptors:
Central chemoreceptors Situation:
- In the deeper part of medulla.
Central chemoreceptors Mechanism:
Carbon dioxide combines with water and form carbonic acid.
Co2+H2O → H2CO3
↓
This dissociated into H + and bicarbonate ion
H2CO3 → HCO3– + H+
↓
Increased H+ ion concentration is main stimulant
↓
It stimulates central chemoreceptors.
↓
This sends impulses to inspiratory center
↓
Causes stimulation of inspiratory centre.
Question 17. Factors effecting Respiratory Centers.
Answer:
1. Impulses from higher centres:
- Ventral surface of frontal cortex inhibits respiration while motor cortex stimulates it.
- Pain and emotional disturbances through hypothalamus stimulates respiration.
- Fever through anterior hypothalamus produces rapid and shallow respiration.
2. Impulses from stretch receptors of lungs called hering – breuer reflex:
During inspiration, lung tissues are stretched.
↓
Stimulation of stretch receptors occurs.
↓
This generates impulses which through vagal afferent fibres reach respiratory centers.
↓
These impulses inhibits inspiratory center.
↓
As a result, inspiration stops and expiration occurs.
3. Afferents from proprioceptors:
- Active or passive movement of joint, stimulates proprioceptors.
- These sends afferent impulses to inspiration center.
- Stimulation of inspiratory center occurs.
- This, in turn, increases rate and depth of inspiration.
4. Impulses from J receptors of lungs:
- J receptors are present in alveoli.
- Its stimulation produces a reflex response characterized by apnea.
5. Impulses from baroreceptors:
- Baroreceptors are stimulated by high BP.
- On stimulation, they send impulses which causes inhibition of respiration.
6. Impulses from chemoreceptors:
- Stimulated by presence of lack of O2 excess of Co2.
- Causes increase in rate and depth of respiration.
7. Cough reflex:
- Caused by irritation of respiratory tract beyond nose.
- Result in stimulation of vagus nerve.
- It begins with deep inspiration followed by forced expiration against a closed glottis.
8. Sneezing reflex:
- It is similar to cough reflex but acts against open glottis.
- It causes stimulation of trigeminal nerve.
Question 18. Classify Hypoxia. Explain each Type of Hypoxia.
Answer:
Hypoxia Types:
- Based on the cause of their production, hypoxia is classified as follows.
Question 19. Artificial Respiration.
Answer:
Artifical respiration is required whenever there is arrest of breathing which occurs during.
- Accidents
- Drowning
- Asphyxia.
- Gas poisoning.
Artificial Respiration Purpose:
- Ventilation of alveoli.
- Stimulation of respiratory centers.
Artificial Respiration Method:
1. Manual method:
- It can be quickly without any medical aid.
- It includes two methods.
Mouth to mouth method:
- Here the subject is kept in supine, position and his head is extended.
- The operator forcibly expires into the mouth of the subject at a rate of 12-15 times per minute till normal respiration is restored.
Holger Neilson method:
- Here the subject is kept in prone position with head turned to one side.
- The operator places his hand over back of subject and applies pressure.
2. Mechanical methods:
- They are employed when artificial respiration has to be sustained for a longer period of time.
- They are of two types.
Drinker’s method:
- In this method, thorax is enclosed in a specially designed tank, in which positive and negative pressure changes are maintained alternatively.
Ventilation method:
- A rubber tube is introduced into the trachea of the subject.
- By using a pump, oxygen is pumped into lungs.
Types of apparatus:
1. Volume ventilator:
- By this, a constant volume of air is pumped into the lungs of the subject.
2. Pressure ventilator:
- By this, air is pumped into the lungs of the subject with constant high pressure.
Question 20. Explain step by step procedure of mouth to mouth method of artificial respiration.
Answer:
Mouth to Mouth Method Of Artificial Respiration Procedure:
- The subject is kept in supine position.
- Clothes around neck and chest regions are loosen.
- Mouth, face and throat are cleared off mucous saliva of foreign particles.
- Tongue is drawn forward to prevent airway obstruction.
- The nostrils of the subject are closed with the thumb and index finger of operator’s hand.
- The lower jaw of the subject is pulled down.
- Next, the operator takes a deep breath and exhales into the subject’s mouth forcefully.
- It is repeated at the rate of 12 – 14 times per minute till normal respiration is restored.
Mouth to Mouth Method Of Artificial Respiration Procedure Advantages:
- Effective method.
- Directly stimulates respiratory centers
- Facilitates onset of respiration.
Mouth to Mouth Method Of Artificial Respiration Procedure Disadvantages:
- Not accepted method due to close contact between operator and subject.
Question 21. Oxygen-Haemoglobin Curve.
Answer:
Oxygen Haemoglobin Dissociation Curve:
- The relationship between the partial pressure of oxygen and the percentage saturation of haemoglobin with oxygen is explained graphically by the oxygen haemoglobin dissociation curve
- It is simoid shaped
- Lower part of curve
- Indicates dissociation of oxygen from haemoglobin
- Upper part of curve
- Indicates acceptance of oxygen by haemoglobin depending upon the partial pressure
- Lower part of curve
Amount of Oxygen Transported in this Form:
- Arterial blood – 19 ml per 100 ml of blood
- Venous blood – 13.88 ml per 100 ml of blood
Question 22. Write a note on different lung volumes and capacities with the help of a diagram. (or) Draw a neat labelled diagram of spirogram and explain various lung volumes and capacities.
Answer:
Lung volumes:
Lung capacities:
- They are combination of two or more lung volumes.
Question 23. What is asphyxia? What are the stages and symptoms of asphyxia?
Answer:
Asphyxia:
- It is the condition characterised by the combination of hypoxia and hypercapnia due to obstruction of air passage
Question 24. Define and discuss
1. Vital capacity
2. Apnoea
Answer:
Vital capacity:
- It is the maximum volume of air that can be expelled out forcefully after a deep inspiration
- It includes inspiratory reserve volume, expiratory reserve volume and tidal volume.
Value:
- Vital capacity inspiratory reserve volume + expiratory reserve volume + tidal volume = 3300+1000+500 = 4800 ml
Factors affecting it:
- Sex
- Age
- Body built
- Posture
- Pregnancy
- Presence of respiratory diseases
Apnoea:
- It is defined as temporary cessation of breathing
Apnea time:
- Normal apnea time is about 40-60 second in normal person after a deep inspiration
Apnea time Types:
- Deglutition apnea – occurs during deglutition
- Voluntary apnea – occurs voluntarily
- Vagal apnea – occurs due to stimulation of vagus nerve
- Adrenaline apnea – occurs after injection of adrenaline
- Hyperventilation apnea – occurs after hyperventilation
Apnea time Effect:
- Prolonged apnea results in the accumulation of carbon dioxide which stimulates respiratory center.
Question 25. Describe the carbon dioxide transport in blood. Add a note on haldane’s effect.
Answer:
Carbon dioxide transport in blood:
- As dissolved form – 7%
- Carbon dioxide diffuses into blood and dissolves in the fluid of plasma forming a simple solution and is transported
- As carbonic acid – negligible
- Carbon dioxide enters the plasma and combined with water to form carbonic acid
- As carbamino compounds – 30%
- In plasma
- Carbon dioxide combines with plasma proteins and forms carbamino proteins
- It is loose bond so can be easily released
- It is reversible reaction
- In RBCs
- Carbon dioxide combines with haemoglobin and forms carbhaemoglobin
- It is also reversible process
- In plasma
- As bicarbonate – 63%
- From plasma carbon dioxide enters the blood
- Here it combines with water present in RBC and forms carbonic acid in the presence of carbonic anhydrase enzyme
- Carbonic acid is unstable compound so it is readily dissociated into bicarbonate and hydrogen ions By this concentration of bicarbonate ion increases in RBCs
- This leads to diffusion of bicarbonate from cell into plasma
- Thus carbon dioxide is transported in this form.
Haldane Effect:
- It is the effect by which combination of oxygen with hemoglobin displaces carbon dioxide from hemoglobin
- The excess of oxygen content in blood causes shift of the carbon dioxide dissociation curve to the right
Haldane Effect Significance:
- Essential for release of carbon dioxide from blood into the alveoli of lungs and uptake of oxygen by the blood
Question 26. Define timed vital capacity. Give its normal value. Mention a condition in which it is decreased.
Answer:
Timed vital capacity:
It is the volume of air that can be expired out forcefully in a given unit of time.
Normal values:
- TVC1-83% of total vital capacity
- TVC2-94% of total vital capacity
- TVC3-97% of total vital capacity
- After third second – 100% of total vital capacity
Decreased in:
- Asthma
- Emphysema
- Fibrosis
Question 27. Types of respiration.
Answer:
1. External respiration:
- It involves absorption of oxygen and removal of carbon dioxide from the body.
- It includes gaseous exchange occurring between lungs and blood.
2. Internal respiration:
- It is the utilization of oxygen and production of carbon dioxide by cells.
- It involves gaseous exchanges between the cells and their fluid medium.
Question 28. Functions of respiratory tract.
Answer:
1. Respiratory function:
- Respiratory tract is involved in gaseous exchange.
2. Non-respiratory functions:
Olfaction:
- Olfactory receptors present in nasal mucous membrane help in olfaction.
Vocalization:
- Larynx, part of respiratory tract helps in the process of vocalization.
Prevention:
- Prevents foreign bodies from reaching the alveoli.
Defensive function:
- Bronchial secretions contains IgA which resist infections.
- Cells of lungs.
- Epithelial lining cells are antimicrobial.
- Leukocytes and macrophages.
- Helps in phagocytosis.
- Mast cells
- Secretes heparin, histamine, serotonin, etc.
- Natural killer cells.
- Destroys viruses and viral infected cells.
Question 29. Surfactant.
Answer:
Surfactant Definition:
- Type II alveolar epithelial cells.
- Clara cells.
Surfactant Functions:
- Reduction of surface tension
- Stabilization of the alveoli
- Inflation of lungs.
- Defensive function.
Question 30. Respiratory pressure. (or) Respiratory dead space.
Answer:
Respiratory Pressure Types:
1. Intrapleural/intrathoracic pressure.
- It is the pressure existing in pleural cavity which is between the visceral and parietal layers of pleura.
- Normal value is 760 mm Hg.
- It is always negative.
2. Intra alveolar/intrapulmonary pressure.
- It is the pressure existing in the alveoli of the lungs.
- Normal value of 760 mm Hg.
- It is negative during inspiration and positive during expiration.
Question 31. Compliance.
Answer:
Compliance Definition:
- The ability of the lungs and thorax to expand is called compliance.
- It is the change in lung volume per unit change in airway pressure.
Compliance Normal value:
1. Compliance of the lungs and the thorax together = 0.3 litre per cm H2O pressure.
2. Compliance of the lungs only= 0.22 litre per cm H2O pressure.
Compliance Measurement:
- The subject is asked to inspired a known volume of air.
- At the end, the intrapleural pressure is measured.
- Then, the air is expired until the volume returns to the original levels.
- The values of volume and pressure are plotted and a curve is obtain.
Compliance Factors effecting
- Lung volume.
- Phase of respiratory cycle
- Effect of gravity.
- Surface tension.
Question 32. What is vital capacity? Enumerate factors affecting vital capacity.
Answer:
Vital capacity:
Factors effecting it:
- Sex
- Age
- Body built
- Posture
- Pregnancy
- Presence of respiratory diseases.
Question 33. Name the lung volumes and capacities.
Answer:
1. Lung Volumes:
- They are the volumes of air breathed by an individual during altered pattern of respiration.
Lung Volumes Types:
- Tidal volume
- Inspiratory reserve volume
- Residual volume.
2. Lung Capacities:
- Two or more lung volumes together are called lung capacities.
Lung Capacities Types:
- Inspiratory capacity.
- Tidal volume + inspiratory reserve volume.
- Expiratory capacity.
- Tidal volume + expiratory reserve volume.
- Vital capacity.
- Tidal volume + inspiratory reserve volume + expiratory reserve volume.
- Total lung capacity.
- Includes all lung volumes.
Question 34. Chloride shift/Hamburger phenomenon.
Answer:
- In plasma, plenty of sodium chloride is present.
- As the blood passes through the capillaries, HCO3 formed in RBCs, enters the plasma along its concentration gradient.
- Sodium chloride dissociates into sodium and chloride ions.
NaCI– → Na+ + CI– - When HCO, enters the plasma, electrical equilibrium is disturbed.
- To maintain this equilbirum the negatively charged chloride ions move into the RBC.
- This is called chloride shift or hamburger phenomenon.
Question 35. Hypoxia.
Answer:
Hypoxia Types:
Hypoxia is classified based on the cause of their production.
- Hypoxic hypoxia.
- Anemic hypoxia.
- Stagnant hypoxia.
- Histotoxic hypoxia.
Question 36. Cyanosis.
Answer:
Cyanosis Definition:
- It is the bluish coloration of skin and/or mucous membrane due to the presence of atleast 5 gm of reduced haemoglobin per 100 ml of blood in capillaries.
Cyanosis Sites where it is seen:
- Mucous membrane of undersurface of tongue
- Lips
- Ear lobes
- Nail
- Tip of nose
Cyanosis Causes:
- Hypoxic hypoxia.
- Stagnant hypoxia.
- Polycythemia.
- Exposure to mild and severe cold.
- Altered haemoglobin formation.
Question 37. Asphyxia.
Answer:
Asphyxia Definition:
- It is the condition characterized by the combination of hypoxia and hypercapnea due to obstruction of air passage.
Asphyxia Causes:
- Strangulation
- Hanging
- Drowning etc.
Asphyxia Stages:
- Stage of hyperpnea
- Stage of convulsion
- Stage of collapse.
Question 38. Apnea.
Answer:
Apnea Definition:
- It is defined as temporary cessation of breathing.
Apnea time:
- Normal apnea time is about 40-60 seconds is normal person after a deep inspiration.
Apnea Types:
- Deglutition apnea – occurs during deglutition
- Voluntary apnea – occurs voluntarily
- Vagal apnea occurs due to stimulation of vagus nerve.
- Adrenaline apnea – occurs after injection of adrenaline.
- Hyperventiliation apnea – occurs after hyperventilation.
Apnea Effect:
- Prolonged apnea results in the accumulation of Co, which stimulates respiratory centre.
Question 39. Dyspnea.
Answer:
Dyspnea Definition:
- Dyspnea is defined as “a consciousness of necessity for increased respiratory effect”.
Dyspnea point:
- It is the increased level of ventilation at which the difficulty in breathing becomes severe.
Dyspnea Causes:
- Respiratory disorders
- Cardic disorders
Dyspenic index:
- It is the index between breathing reserve and maximum breathing capacity.
Question 40. Effects of Hyperventilation.
Answer:
- Washing out of excess carbondioxide.
- Reduction in partial pressure of carbon dioxide.
- Suppression of respiratory centers
- Causes apnea.
- Apnea is followed by cheyne-strokes type of breathing.
Question 41. Hypoventilation.
Answer:
Hypoventilation Definition:
- The decrease in the pulmonary ventilation is called hypoventilation.
Hypoventilation Causes:
- Suppression of respiratory centers.
- Paralysis of respiratory muscles.
Hypoventilation Effects:
- Hypoxia, hypercapnea, dyspnea.
- Increase in rate and force of respiration.
- Lethargy, coma and death occurs in severe conditions.
Question 42. Pneumonia.
Answer:
Pneumonia Definition:
- It is the inflammation of lung tissues followed by the accumulation of blood cells, fibrin and exudates in the alveoli.
Pneumonia Causes:
- Bacterial or viral infections.
- Inhalation of toxic substances.
Pneumonia Types:
- Lobar pneumonia.
- Lobular pneumonia.
Pneumonia Effects:
- Fever, sleeplessness, delirum.
- Chest pain, shallow breathing.
- Cyanosis.
Question 43. Bronchial asthma..
Answer:
Bronchial asthma Definition:
- It is the respiratory disease characterized by difficult breathing with wheezing.
Bronchial asthma Causes:
- Inflammation of air passage.
- Hypersensitivity of nerve endings in larynx and nose.
- Pulmonary edema.
- Congestion of lungs.
Bronchial asthma Features:
- It is paroxysmal disorder.
- More difficulty occurs during expiration.
- Chest compression occurs.
- There is severe contraction of abdominal muscles.
- Bronchioles are constricted and produces whistting sound.
- Reduction in PO2 occurs in blood.
- Acidosis, dyspnea and cyanosis occurs.
Question 44. Carbon monoxide poisoning.
Answer:
Carbon Monoxide Poisoning Features:
It depends on concentration of carbon monoxide.
- 1% of Co-causes headache and nausea.
- Above of 1% co in air (C’s)
- Causes convulsion, cardic arrest, loss of consciousness and coma.
- Haemoglobin saturation of Co becomes 30 – 40%.
- Haemoglobin saturation of Co above 50% leads to death.
Carbon Monoxide Poisoning Treatment:
- Immediate stoppage of Co exposure
- Providing adequate ventilation.
- Artifical respiration.
- Administration of 100% oxygen.
- Administration of air with few percent of Co2.
Question 46. Respiratory Quotient.
Answer:
Respiratory Quotient Definition:
- The molar ratio of carbon dioxide production to oxygen consumption is called respiratory quotient.
Respiratory Quotient Significance:
- Determine the utilization of different food stuffs.
Respiratory Quotient Normal value:
Question 47. Artificial Respiration
Answer:
Artificial Respiration Methods:
1. Manual method:
- Mouth to mouth
- Holger vielson method.
2. Mechanical method:
- Drinker’s method
- Ventilation method.
Question 48. Kortkoff sounds
Answer:
- Korotkoff sounds are blood flow sounds that clinician observe while taking blood pressure with a sphygmomanometer over the brachial artery in the antecubital fossa.
- These sounds appear and disappear as the blood pressure cuff is inflated and deflated.
- There are five kortokoff sounds
- Appearance of first sound indicates systolic blood pressure
- Disappearance of sound helps to measure the diastolic blood pressure.
Question 49. In what forms can carbon dioxide be transported?
Answer:
Forms of carbon dioxide:
- As dissolved form – 7%
- As carbonic acid – negligible
- As carbamino compounds -30%
- As bicarbonate – 63%
Question 50. Acclimatization
Answer:
- Acclimatization refers to the adaptations or the adjustment by the body in high attitude
- While staying at high attitude for several days to several weeks the body gets slowly adapted to the low oxygen tension
Changes Acclimatization occurs:
- Changes in blood
- RBC count, PCC, Haemoglobin content and oxygen carrying capacity of blood increases
- Changes in cardiovascular system
- Increase in rate and force of contraction of heart
- Increase in cardiac output and blood pressure
- Respiratory system
- Pulmonary hypertension develops
- Pulmonary ventilation increases
- Diffusing capacity of gases increases
- Changes in tissues
- Increase in the number of mitochondria
Question 51. Give normal values of
1. Tidal volume
2. Maximum voluntary ventilation.
Answer:
Normal values:
- Tidal volume – 500 ml
- Maximum voluntary ventilation – 4.2 litres/min
Question 52. Mention the partial pressures of oxygen and carbon dioxide in arterial and venous blood.
Answer:
Partial pressure:
Question 53. Give the contents of oxygen in blood. Define tidal volume and give the value.
Answer:
Contents of oxygen in blood:
- Arterial blood – 19 ml%
- Venous blood – 14 ml%
Tidal volume Definition:
- It is the volume of air breathed in and out of lungs in a single normal quiet breathing
Tidal Value:
- 500 ml
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