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WelcomeRespiratory
System
Respiratory Respiratory SystemSystemRespiratory Respiratory SystemSystem
Cardiovascular
System
Respiratory System
NoseNose
• Respiration :• The interchange at gases between an organism & medium in
which it lives that the taking of oxygen (O2), its use in tissue & the giving of CO2 is called respiration .
• • C6H12O6 + 6O2 → 6CO2 + 6H2O + Large amount of energy • Two Phages :• • A. Inspiration :- It means intake of air into lungs . Its duration is
about 2 sec.• B. Expiration :- It means output of air from lungs . Its duration is
about 3 sec.
Functions of Respiration :
• I. Gas Transfer :- O2 from alveoli to venous blood & CO2 is opposite direction .
• II.Metabolic function :- O2 is essential for maintenance of metabolism in the tissue .
• III.Excretion :- It excretes volatile substance like NH3 , ketone bodies , essential oils , alcohols , water vapour etc .
• IV.Regulation of partial pressure of CO2 (PCO2 ):- The most important functions of respirations is to keep the arterial PCO2 at 40 mmHg which is essential for many vital functions of the body .
• V.Regulation of pH of blood :- It regulates the pH of blood by the following reversible reaction –
• H2CO3 ↔ H + + HCO3
• VI.Pumping action :- The rhythmic movement at the diaphragm & chest wall causes rhythmic alteration of pressure in the abdomen & chest cavity . This assist in drawing blood from the lower part of the body to the abdomen & then to the chest ,it helps in maintaining venous inflow of the heart .
Functions of Respiration :
• VII.Maintenance of temperature balance :- When water is transformed into gaseous form heat is absorbed , so heat is lost through H2O vapour . About 10% of body heat is changed in this way .
• VIII. Maintenance of H2O balance :- 600-800 ml of water per day is lost or water vapour during expiration .
• IX.Blood & Lymph return :- Effect heart rate & CO through nervous mechanism.
• X.Blood pressure :- Increase or decrease due to respiration .• XI.Body Defense :- Secondary protection of the body from inhaled
the particle . Filter the blood that enter into the systemic circulation .• XII.Endocrine function :- Conversion of Angiotensin- I to II by the
help of ACE , thus control BP . Also help to secrete Prostaglandin , Bradykinin , Histamine , Serotonin , Ach .
Types of Respiration :-
1. External respiration
2. Internal respiration
• 1. External Respiration :- O2 in & CO2 out (removal) .
• 2. Internal Respiration :- The utilization of O2 & production of CO2 by cell & the gaseous exchange between the cell and their fluid medium is called internal respiration .
• Four Stages of Respiration :- 1. Pulmonary Ventilation :- Inflow & outflow of air between alveoli and
atmosphere .2. Diffusion of O2 & CO2 between alveoli and blood .3. Transport 4. Regulation
• Respiration Rate :- • The rate of respiration depends upon the following things ---• Age• Sex• Size• Work• Rest• Sleep
• At Birth :- 14 – 60 per min• Adult ( male or female ) :- 10 – 18 per min
Conditions increase rate of Respiration :-
( Respiration & level of Metabolism )• Physiologic → Nervous excitement , Muscle
exercise , High altitude, Increase temperature .
• Chemical → Increase CO2 , decrease O2
• Pathological → Fever , Defective formation of blood .
• Conditions decrease rate of Respiration :-
Opium , Barbiturate poisoning .
• Muscles of Respiration :- 1. Inspiration :
• Quite Inspiration :- Diaphragm : It increases the vertical diameter of the thoracic cavity .External Intercostals : It increases the anterio-posterior & transverse diameter of the cavity .
• Forceful Inspiration :-Sternomastoid , Anterior serrati , Scalenus posterior , Latissimus dorsi .
2. Expiration :• Quite Expiration :- Does not involve any muscle .• Forceful Expiration :- Abdominal recti , Internal
intercostals , Serratus posterior , Interior muscles .
Mechanism of Respiration / Breathing Mechanism :- 1. Mechanism of Inspiration :-
• • • Signals from respiratory center • • • • • Phrenic Nerve Intercostal nerve• ( it arises from the ( these are the anterior• 3rd,4th,5th cervical division of the thoracic • Spinal nerve ) spinal nerve from T1- T2)• • • Contraction of Diaphragm Contraction of external • Intercostals muscle • • ↑vertical diameter of • Chest cavity ↑Anterio-posterior & • transverse diameter of • chest cavity .• Chest wall expansion • • • Negative intrapleural Negative alveolar pressure• pressure, -7.5 cm of H2o/ -1 cm of H2O / 1 mm of Hg• -6 mm of Hg• • • Expansion of lung • • • • Air flow into the lung• • • Inspiration•
Mechanism of Expiration :-
• Signals from respiratory centers• • • • Phrenic nerve Intercostal nerve• • • • Relaxation of diaphragm Relaxation of respiratory• muscles & contraction of • expiration muscle .• • ↓vertical diameter of • Chest cavity • Lungs recoil pulls the back• to expiratory position .• • Contraction of lungs• • ↑ Recoil pressure • • • • • Slightly positive airway pressure • • • Air flown out from lungs• • • • Expiration
Differences between Respiration & Ventilation:-• Respiration is a dynamic process,involves gas exchange (eg-CO2 & O2 )
either at the alveolar capillary level or that the tissue-cellular level.• Ventilation also a dynamic process,that involves contraction of the
respiratory muscles with subsequent changes of air through the airways & into the alveoli.
• Lung Volume:-• Lung volume are non overlapping fraction of the gas content.• Lung Capacities:-• The lung capacities are dynamic entities & are employed to describe events
in the pulmonary cycle, and also to assess lung function.• There are four types of volume & four capacities exist.Volume• The Tidal volume(TV)- It is the volume of air inspired or expired during
normal quiet breathing. It amount to about 500 ml in adult male.• The inspiratory reserve volume(IRV)- It is the extra volume of air that can be
inspired over & above the normal tidal volume when the person inspire with full force.It is usually to about 3000
• The expiratory reserve volume(ERV)- The expiratory reserve volume is the maximum extra volume of air that can be expired by forceful expiration after the end of a normal tidal expiration.This normally amounts to about 1100 ml.
• The residual volume(RV)- The RV is the volume of air remaining in the lungs after the most forceful expiration. This volume average about 1200 ml.
Position of Lungs
The LungsLarynxLarynx
The Bronchial Tree
TracheaTrachea
BronchusBronchus
BronchioleBronchiole
Alveolar ductAlveolar duct
The organs of the respiratory system
nose pharynx larynx trachea bronchi
bronchioles
alveolar ducts and the alveoli
Within the lungs
Leading to the lungs
The Pathway• Air enters the nostrils
• passes through the nasopharynx,
• the oral pharynx
• through the glottis
• into the trachea
• into the right and left bronchi, which branches and rebranches into
• bronchioles, each of which terminates in a cluster of
AlveoliOnly in the alveoli does actual gas exchange takes place. There are
some 300 million alveoli in two adult lungs. These provide a surface
area of some 160 m2 (almost equal to the singles area of a tennis court
and 80 times the area of our skin!).
The nose
The external nose is formed by the two nasal bones and by cartilage.
It is both covered and lined by skin and inside there are hairs which help to prevent foreign materials from entering.
The nasal cavity is a large cavity divided by a septum.
……nose
• Some of the bones surrounding the nasal cavity are hollow.
• The hollows in the bones are called the paranasal sinuses.
• All the paranasal sinuses are lined with mucous membrane and all open into the nasal cavity
PS
The Pharynx
1. The naso-pharynx - lies behind the nose,
2. The oro-pharynx- lies behind the mouth,
3. The laryngeal pharynx- lies behind the larynx.
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The larynx
• The larynx is composed of several irregular cartilages joined together by– ligaments and
– membranes.
Alveoli
Alveolus
The trachea
• Begins below the larynx and runs down the front of the next into the chest.
• It divides into the right and left main bronchi.
• It is about 12 cm long. • On either side of the
trachea, lie the lungs with the lobes of the thyroid gland above them.
The bronchial tree
TracheaTrachea
BronchusBronchus
BronchioleBronchiole
Alveolar ductAlveolar duct
Trachea
• The wall of the trachea is made of involuntary muscle and fibrous tissue strengthened by the horse-shoe like incomplete ring of hyaline cartilage.
• The trachea is lined with ciliated epithelium containing goblet cells which secrete mucus.
• The cilia sweep the mucus and foreign particles upwards towards the larynx.
The lungs
• The lungs are a pair of spongy conical-shape organs, each enveloped in a serous membrane. They extend from the root of the neck to the diaphragm.
• The lungs are divided into lobes. The left lung has two lobes, separated by the oblique fissure. The right lung has three lobes.
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The alveolar ducts
• The terminal bronchioles branch repeatedly to form minute passages called alveolar ducts, from which alveolar sacs and alveoli open.
The Alveoli
• The alveoli are surrounded by a network of capillaries.
• Deoxygenated blood enters the capillary network from the pulmonary artery
• It is the capillary network that the exchange of gases takes place between the air in the alveoli and the blood vessels.
The pleura
• The pleura is a serous membrane which surrounds each lung.
• It is composed of flattened epithelial cells on a basement membrane and it has two layers.
• The visceral pleura are firmly attached to the lungs, covering their surfaces.
……….pleura
• At the root of the lungs the visceral layer is reflected back to become the parietal layer which lines the chest wall and covers the superior surface of the diaphragm.
• The space between the two layers of the pleura contains serious fluid which enables them to glide over another without friction.
Gaseous Exchange
Disorders
• Bronchitis• Common Cold • Bronchiectasis • Cough • Epiglottitis • Hay Fever • Pertussis • Alveolitis • Tuberculosis
• Pneumonia • Pneumothorax • Pleurisy • Croup • Sinusitis• Tonsilitis• pharyngotonsilitis• Lung Cancer
Disorders of the Respiratory System
• Obstructive Airways Disease• Asthma
– Asthma is a reversible obstructive airways disease of varying severity.
– The symptoms are caused by constriction of the bronchial smooth muscle (bronchospasm),
• oedema of bronchial mucous membranes, and • blockage of the smaller bronchi with plugs of
mucous.
………asthma
• Asthma may occur, particularly in children, as a result of identifiable trigger factors or allergen (extrinsic asthma).
• Immunological mechanisms involving specific allergens (e.g. house-dust mite, pollens and animal dander) may be responsible.
….asthma
• Non-specific trigger factors include – viral infection – exercise – dust and irritants (e.g. cigarette
smoke) – beta-adrenoceptor blocking drugs– NSAIDs (e.g. aspirin, indomethacin
etc.) and– emotional disturbances
Chronic Obstructive Pulmonary Disease (COPD)
Irritation of the lungs can lead to asthma, emphysema, and chronic bronchitis. And, in fact, many people develop two or three of these together. This constellation is known as chronic obstructive pulmonary disease (COPD).
Among the causes of COPD are
•cigarette smoke (often)
•cystic fibrosis (rare)
Cystic fibrosis is a genetic disorder caused by inheriting two defective genes for CFTR, a transmembrane protein needed for the transport of Cl- ions. The lungs produce copious amounts of a heavy mucus that plugs the airways interfering with breathing and causing a persistent cough. Cystic fibrosis is the most common inherited disease in the U.S. white population.
EmphysemaIn this disorder, the delicate walls of the alveoli break down, reducing the gas exchange area of the lungs. The condition develops slowly and is seldom a direct cause of death. However, the gradual loss of gas exchange area forces the heart to pump ever-larger volumes of blood to the lungs in order to satisfy the body's needs. The added strain can lead to heart failure.
Chronic BronchitisAny irritant reaching the bronchi and bronchioles will stimulate an increased secretion of mucus. In chronic bronchitis the air passages become clogged with mucus, and this leads to a persistent cough. Chronic bronchitis is usually associated with cigarette smoking.
PneumoniaPneumonia is an infection of the alveoli. It can be caused by many kinds of both bacteria (e.g., Streptococcus pneumoniae) and viruses. Tissue fluids accumulate in the alveoli reducing the surface area exposed to air. If enough alveoli are affected, the patient may need supplemental oxygen.
Drugs• Bronchodilators
– Pulmolin– Filin
• Antihistamine– Citin– Lora– Histal
• Antibiotics– Moxin– Cephran– Azicin– Ceftid– Ciprox
AsthmaIn asthma, periodic constriction of the bronchi and bronchioles makes it more difficult to breathe in and, especially, out. Attacks of asthma can be
•triggered by airborne irritants such as chemical fumes and cigarette smoke
•airborne particles to which the patient is allergic. Link to discussion of allergic asthma.
1. The SINUSES (frontal, maxillary, and sphenoidal) are hollow spaces in the bones of the head. Small openings connect them to the nose. The functions they serve include helping to regulate the temperature and humidity of air breathed in, as well as to lighten the bone structure of the head and to give resonance to the voice.
2. The NOSE (nasal cavity) is the preferred entrance for outside air into the respiratory system. The hairs that line the wall are part of the air-cleaning system.
3. Air also enter through the MOUTH (oral cavity), especially in people who have a mouth-breathing habit or whose nasal passages may be temporarily obstructed, as by a cold or during heavy exercise.
4. The ADENOIDS are lymph tissue at the top of the throat. When they enlarge and interfere with breathing, they may be removed. The lymph system, consisting of nodes (knots of cells) and connecting vessels, carries fluid throughout the body. This system helps to resist body infection by filtering out foreign matter, including germs, and producing cells (lymphocytes) to fight them.
5. The TONSILS are lymph nodes in the wall of the throat (pharynx) that often become infected. They are part of the germ-fighting system of the body.
6. The THROAT (pharynx) collects incoming air from the nose and mouth and passes it downward to the windpipe (trachea).
7. The EPIGLOTTIS is a flap of tissue that guards the entrance to the windpipe (trachea), closing when anything is swallowed that should go into the esophagus and stomach.
8. The VOICE BOX (larynx) contains the vocal chords. It is the place where moving air being breathed in and out creates voice sounds.
9. The ESOPHAGUS is the passage leading from the mouth and throat to the stomach.
10. The WINDPIPE (trachea) is the passage leading from the throat (pharynx) to the lungs.
11. The LYMPH NODES of the lungs are found against the walls of the bronchial tubes and windpipe.
12. The RIBS are bones supporting and protecting the chest cavity. They move to a limited degree, helping the lungs to expand and contract.
13. The windpipe divides into the two main BRONCHIAL TUBES, one for each lung, which subdivide into each lobe of the lungs. These, in turn, subdivide further.
14. The right lung is divided into three LOBES, or sections. Each lobe is like a balloon filled with sponge-like tissue. Air moves in and out through one opening -- a branch of the bronchial tube.
15. The left lung is divided into two LOBES.
16. The PLEURA are the two membranes, actually one continuous one folded on itself, that surround each lobe of the lungs and separate the lungs from the chest wall.
17. The bronchial tubes are lines with CILIA (like very small hairs) that have a wave-like motion. This motion carried MUCUS (sticky phlegm or liquid) upward and out into the throat, where it is either coughed up or swallowed. The mucus catches and holds much of the dust, germs, and other unwanted matte that has invaded the lungs. You get rid of this matter when you cough, sneeze, clear your throat or swallow.
18. The DIAPHRAGM is the strong wall of muscle that separates the chest cavity from the abdominal cavity. By moving downward, it creates suction in the chest to draw in air and expand the lungs.
19. The smallest subdivisions of the bronchial tubes are called BRONCHIOLES, at the end of which are the air sacs or alveoli (plural of alveolus).
20. The ALVEOLI are the very small air sacs that are the destination of air breathed in. The CAPILLARIES are blood vessels that are imbedded in the walls of the alveoli. Blood passes through the capillaries, brought to them by the PULMONARY ARTERY and taken away by the PULMONARY VEIN. While in the capillaries the blood gives off carbon dioxide through the capillary wall into the alveoli and takes up oxygen from the air in the alveoli.
