The document discusses respiration and its various mechanisms and regulatory processes. It describes that respiration involves the movement of oxygen from the environment to cells and carbon dioxide in the opposite direction. This occurs through two main processes: breathing and gas exchange. It details the steps in respiration including breathing, gas diffusion between alveoli and blood, transport of gases, gas diffusion between blood and tissues, and utilization of oxygen. It discusses the roles of muscles in inspiration and expiration. It also outlines respiratory volumes, capacities, the exchange and transport of gases, and the regulation of respiration through the respiratory center and chemoreceptors.

1. RESPIRATION-
MECHANISM & REGULATION
Course- HUMAN PHYSIOLOGY (FN 513)
Submitted To-Dr. Neerja Singla
Submitted By- Simarpreet Kaur

2. RESPIRATION
In physiological terms, respiration is the movement
of oxygen from the outside environment to the cells
within tissues, and removal of carbon dioxide in the
opposite direction, i.e. to the environment.
This involves two main processes:
1. Breathing
2. Gas exchange

3. STEPS INVOLVED IN RESPIRATION
Respiration is a complex process which occurs in number of steps.
These are:
1. Breathing
2. Diffusion of gases b/w alveoli and blood
3. Transport of gases
4. Diffusion of gases b/w blood and tissues
5. Utilisation of O2

4. BREATHING
 Supplies oxygen to the alveoli and excretes carbon
dioxide.
 The average breathing/respiratory rate is 12-15
breaths per minute.
 Each breath consists of three phases: inspiration,
expiration and pause.
 Breathing depends on changes in pressure and volume
in the thoracic cavity.
 Principle -Increasing the volume of a container
decreases the pressure inside it, and vice versa.

5. INSPIRATION
• During inspiration, the external intercostal muscles and the diaphragm contract
simultaneously, enlarging the thoracic cavity in all directions.
Air enters from atmosphere to the lungs as it moves
from higher pressure to lower pressure
Decrease in pressure within the pulmonary cavity
Similar increase in volume of Pulmonary cavity
Increase in volume of Thoracic cavity
• The process of inspiration is active, because it needs energy for muscle contraction.
• At rest, inspiration lasts about 2 seconds.

6. INSPIRATION

7. ROUTE OF INSPIRATION

8. EXPIRATION
Expulsion of air from higher pressure in lungs to lower
pressure in atmosphere
Increase in pressure within the pulmonary cavity
Similar decrease in volume of Pulmonary cavity
Decrease in volume ofThoracic cavity
• Moving of air out of lungs if the pressure within the lungs is more than atmospheric pressure.
• Relaxation of muscles increases pressure inside the lungs and expels air from the respiratory tract.
• This process is passive, as it does not require the expenditure of energy.
• Expiration lasts about 3 seconds.

9. EXPIRATION
Relaxation of the external
intercostal muscles and the
diaphragm reduces the thoracic
as well as pulmonary volume.

10. ROUTE OF EXPIRATION

11. SUMMARY
Role of muscles in inspiration and expiration
STAGE OF
BREATHING
MUSCLES INVOLVED CONTRACTION/
RELAXATION
VOLUME OF
THORACIC
CAVITY
NORMAL
INSPIRATION
DIAPHRAGM CONTRACT INCREASE
EXTERNAL INTERCOASTAL
MUSCLE
CONTRACT
NORMAL
EXPIRATION
DIAPHRAGM RELAX DECREASE
EXTERNAL INTERCOASTAL
MUSCLE
RELAX
FORCEFUL
EXPIRATION
INTERNAL INTERCOASTAL
MUSCLES
CONTRACT DECREASE
ABDOMINAL MUSCLES CONTRACT

12. RESPIRATORY
VOLUMES
Quantity of air which our lungs can hold or expel under different
conditions.
 Tidal volume (TV)
Amount of air passing into and out of the lungs during each cycle of
breathing (about 500 mL at rest)
 Inspiratory reserve volume (IRV)
Extra volume of air over and above normal that can be inhaled into
the lungs during forceful inspiration. (2500-3000 ml)
 Expiratory reserve volume (ERV)
Additional volume of air that can be expelled over and above normal
TV during forceful expiration. (1000-1100 ml)
 Residual volume (RV)
Volume of air remaining in the lungs after forced expiration. (1100-
1200 ml)

13. RESPIRATORY CAPACITIES
Sum of two or more respiratory volumes.
• Inspiratory capacity (IC)
Amount of air that can be inspired with maximum effort.
• Expiratory capacity (EC)
Amount of air that can be expired with maximum effort.
• Functional residual capacity (FRC)
Amount of air remaining in the lungs after normal
expiration.
• Vital capacity (VC)
Maximum volume of air that a person can inspire after
forceful expiration or can expire after forceful inspiration.
• Total lung capacity (TLC)
Maximum amount of air the lungs can hold.
RESPIRATORY CAPACITIES FORMULAE
Inspiratory capacity TV + IRV
Expiratory capacity TV + ERV
Functional residual capacity ERV + RV
Vital capacity TV + IRV+ ERV
Total lung capacity RV + ERV + IRV +TV

14. EXCHANGE OF GASES
• Exchange of gases occurs when a difference in partial
pressure exists across a semipermeable membrane.
• Diffusion of O2 and CO2 depends on pressure differences
between atmospheric air and the blood in external
respiration, or blood and the body tissues in internal
respiration.
• Diffusion takes place from a region of their higher partial
pressure to lower partial pressure.

15. RATE OF DIFFUSION
 Solubility of gases: A gas having high solubility, diffuses at a faster rate. Solubility of CO₂ is 20-
25 times higher than that of O2, the amount of CO₂ that diffuses across diffusion membrane is
much higher than that of O2.
 Partial pressure: O2, is diffused from atmospheric air having partial pressure 159 mm Hg to
the alveoli where pO2, is less, i.e. 104 mm Hg.
 Thickness of membrane: More the thickness of membrane, less will be the rate of diffusion.
For efficient diffusion to occur, membrane should be very thin.

16. EXCHANGE OF GASES
There are two sites where exchange of gases takes
place:
1. Exchange of Gases between Alveoli and Blood
(EXTERNAL RESPIRATION)
2. Exchange of Gases between Blood and Tissues
(INTERNAL RESPIRATION)

17. EXTERNAL RESPIRATION
Exchange of Gases between Alveoli and Blood
• Each alveolar wall is one cell thick and is surrounded by a
network of tiny capillaries.
• Venous/deoxygenated blood arriving at the lungs via the
pulmonary artery has high pCO2 and low pO2.
• Carbon dioxide diffuses from venous blood down its
concentration gradient into the alveoli until equilibrium
with alveolar air is reached.
• By the same process, oxygen diffuses from the alveoli into
the blood.
Therefore, O2, moves from atmospheric air to alveoli and then finally to blood, whereas the
CO₂ moves from deoxygenated blood to alveoli and finally to atmospheric air.

18. INTERNAL RESPIRATION
Exchange of Gases between Blood and Tissues
• O2, and CO₂ are exchanged from blood capillaries to body cells and
from body cells to blood capillaries, respectively.
• The pO2, is higher in systemic arteries carrying oxygenated blood
than that in tissues or body cells.
• O2, moves from systemic arteries to body cells where it is utilised
for catabolic reaction during which CO2, H2O and energy are
produced.
• As CO2 is produced in the body cells, the pCO2, is increased within
the body cells than that in blood capillaries.
• Therefore, CO₂ moves from body cells to the capillary blood
through tissue fluid. Deoxygenated blood is carried to the heart
and hence to the lungs via pulmonary artery.

19. SUMMARY
RESPIRATORY
GAS
ATMOSPHERIC
AIR
ALVEOLI OXYGENATED
BLOOD
TISSUES DEOXYGENATED
BLOOD
pO2 (mm Hg) 159 104 95 40 40
pCO2 (mm Hg) 0.3 40 40 45 45

20. TRANSPORT OF GASES
Oxygen
 Oxygen is carried in the blood:
• in chemical combination with haemoglobin as oxyhaemoglobin (98.5%)
• dissolved in plasma water (1.5%).
 Oxyhaemoglobin is unstable and under certain conditions readily
dissociates, releasing oxygen.
 Low O2 levels, low pH (acidic) and raised temperature increase oxygen
dissociation.
Active tissues produce increased quantities of CO2 and heat, which leads to increased release
of oxygen. In this way, oxygen is available to tissues in greatest need.

21. TRANSPORT OF GASES
Carbon dioxide
 CO₂ is excreted by the lungs and is transported by three mechanisms:
• As bicarbonate ions (HCO3) in the plasma (70%)
• Combined with haemoglobin in RBCs as carbaminohaemoglobin (23%)
• Dissolved in the plasma (7%)
 Carbon dioxide levels must be controlled, as either excess or deficiency leads to significant disruption of
acid base balance.
 Excess CO2 reduces blood pH as it dissolves in body water to form carbonic acid.
 Sufficient CO2, is essential for the bicarbonate buffering system.

22. REGULATION OF RESPIRATION
The respiratory centre
 Formed by groups of nerves in the medulla oblongata, the
respiratory rhythmicity centre controls the respiratory
pattern, i.e. the rate and depth of breathing.
 Three important groups of neurones regulate breathing:
• an inspiratory group,
• an expiratory group, and
• neurones in the pneumotaxic area.
 Motor impulses leaving the respiratory centre pass in the
phrenic and intercostal nerves to the diaphragm and
intercostal muscles, respectively, to stimulate respiration.

23. REGULATION OF RESPIRATION
Chemoreceptors
Respond to changes in the pO2 and pCO2 of the blood and cerebrospinal fluid
(CSF). They are located centrally and peripherally.
 Central chemoreceptors
• Located on the surface of the medulla oblongata and bathed in cerebrospinal
fluid CSF.
• When arterial pCO2, rises (hypercapnia), the central chemoreceptors respond
by stimulating the respiratory centre, increasing the rate and depth of
breathing to reduce arterial pCO2.
 Peripheral chemoreceptors
• Situated in the arch of the aorta and in the carotid bodies.
• Rise in pCO₂ activates receptors, triggering nerve impulses to the respiratory
centre via the glossopharyngeal and vagus nerves which increases the rate
and depth of respiration.
• Increase in blood acidity also stimulates these chemoreceptors, increasing
ventilation to increase CO2 excretion and increase blood pH.

24. ROLE OF NUTRITION IN
RESPIRATORY HEALTH

25. KEY
FINDINGS
 The Mediterranean diet has protective effects for allergic
respiratory diseases.
 The “western” dietary pattern, characterised by high consumption
of refined grains, cured and red meats, desserts and sweets, has
been associated with increased risk of asthma in children and
COPD.
 Fruit and vegetable intake has potential benefits in association
with respiratory conditions due to consisting of antioxidants,
vitamins, minerals, fibre and phytochemicals.
 Omega-3 polyunsaturated fatty acids (PUFA) have been shown to
be anti-inflammatory being associated with improved lung function
and decreased risk of asthma ,and wheeze.

26. KEY
FINDINGS
 Dietary antioxidants are an important dietary factor in protecting
against the damaging effects of oxidative stress in the airways.
Antioxidants including vitamin C, vitamin E, flavonoids and
carotenoids (α- and β-carotene, lycopene) have beneficial effects
on respiratory health
 Consumption of fruit, a rich source of vitamin C, was related to
reduced wheezing and vitamin C intake was negatively associated
with wheezing.
 Vitamin C supplementation was able to prevent smoke induced
emphysema and also to restore damaged lung tissue and decrease
oxidative stress caused by smoke induced emphysema.
 Some minerals have also been found to be protective in respiratory
conditions. Calcium, magnesium and potassium are inversely
linked to asthma.

27. Relationship
of Nutrition
and
Obstructive
Lung
Diseases:
Dietary factors that have been linked to respiratory disease.
√ evidence suggests positive effect, ⨯ evidence suggests
negative effect, ? evidence is lacking.

28. Possible role of nutrients in
COVID-19 pulmonary
pathophysiology
(A) inhibit SARS-CoV-2 infection.
(B) inhibit viral replication of
SARS-CoV-2.
(C) antioxidant role
(D) anti-inflammatory activity and
may inhibit the deleterious
effects of the tissue damage
present in COVID-19.
(E) vitamin D demonstrated a
relevant role in lowering the
risk of oxidative stress.

29.  Data obtained from the Korean National Health and
Nutrition Examination Survey (KNHANES) was used.
 In mild to moderate COPD patients, the low protein
intake group was significantly associated with increased
risk of acute exacerbations and increased hospitalization
compared with the non-low protein intake group.
 The analysis revealed that the amount of protein intake
was associated with forced vital capacity FVC and forced
expiratory volume FEV predicted.
 These findings suggest that patients should be
encouraged to consume adequate protein for disease
management.

30.  High Citrus fruit intake compared to the low intakes had a
9% reduction in lung cancer risk.
 The risk of developing lung cancer was found to be
minimum at a dose of 60g/ day of citrus intake.
 Citrus fruit intake was negatively associated with the risk of
lung cancer.

31. REFERENCES
• Immunomodulatory Role of Nutrients: How Can Pulmonary Dysfunctions Improve?
• Nutrition and Respiratory Health
• Effect of low protein intake on acute exacerbations in mild to moderate chronic obstructive
pulmonary disease: data from the 2007–2012 KNHANES
• Citrus fruit intake and lung cancer risk: A meta-analysis of observational studies
• Human Anatomy and Physiology by Ross & Wilson
• NCERT Biology, Class 11
• Wikipedia

32. THANKYOU