☆Regulation/ Control of Respiratory system

Respiratory system is under dual control : Nervous control and Chemical control.

Nervous control :-

Normal quiet breathing occurs involuntarily. Humans breath about 12 times a minute , but their infants breathe about 44 times a minute . This steady rate is controlled by group of neurons located in the medulla oblongata and pons varoli.
  The respiratory center regulates the rate and the depth of breathing. It divided into three major groups of neurons are —

1- Dorsal respiratory group of neurons ( inspiratory center )

These are located in the dorsal portion of the medulla oblongata. This group of neurons mainly causes inspiration.

2- Ventral respiratory group of neurons ( expiratory center)

These are located in the ventrolateral part of the medulla oblongata. These send signals for both inspiration and expiration.

Note -; These two centers are influenced by stretch receptors and chemoreceptors.

3- Pneumonia center -:

It is located in the dorsal part of pons varolii. It send signals to all the neurons  of dorsal respiratory group and only two inspiratory neurons of ventral respiratory groups. It main job is to primarily limit inspiration.

Chemical control :-

Large no. of Chemoreceptor are located in   carotid bodies. which are located bilaterally in the bifurcation of the common carotid arteries. Their afferent nerve fibres pass through glossopharyngeal cranial nerves(9th) and hence to the dorsal respiratory group of neurons .
   Sizeable number of chemoreceptors are also located in the aortic bodies which are located along  the arch of the aorta. Their afferent nerve fibres pass through the vagi carnial  nerves (10th ) and hence to the dorsal  respiratory group of neurons.

☆Diseases of Respiratory system

  Respiratory system diseases are also called lung diseases . It  are pathological  conditions affecting the lungs and other parts of respiratory system and that make gas exchange difficult in air-breathing . They include conditions of the respiratory tract including the trachea, bronchi, bronchioles, alveoli, pleurae, pleural cavity, and the nerves and muscles of respiration.

Respiratory system diseases may be caused by infection .  8 Top diseases of Respiratory system with prevention and treatment .

1- Hypoxia -:

Hypoxia is a condition of oxygen shortage in the tissue .

Respiratory system diseases is hypoxia
Diagram of Hypoxia
  • It is of two types :-
 a -Artificial Hypoxia –

It results from shortage of oxygen in the air as at high ( over 2400 m) altitudes. It causes mountain sickness characterised by breathlessness , headache, dizziness, nausea, vomiting, mental fatigue,and bluish tinge on the skin and mucous membranes.

b- Anaemic Hypoxia –

  It results from the reduced oxygen – carrying capacity of the blood due to anaemia ( decreased haemoglobin content in blood ) and carbon monoxide poisoning (some haemoglobin occupied by CO ).

By avoiding circumstances which are reduce the oxygen in the environment  . 
– Patients of disease suffer from asthma should regular with their medication .

  The treatment is to restore shortage pressure of oxygen in the blood to normal work and relief the patient .The disease of hypoxia has identified and treat according to symptom .

2-Asphyxia (Suffocation) -:

The O2 content of blood falls whilst the CO2 content rises and paralysis the respiratory center. Breathing stops and death occurs.


3- Bad Cold -:

Disease causing microbes present in the air attack respiratory , producing inflammation of the mucous membrane in various regions  and increased secretion –

a- rhinitis in the nasal chambers ;

b – sinusitis in the sinuses ;

c- pharyngitis in the pharynx often called throat  and usually accomplished by tonsillitis.

Suffering form cold diseases
Bad cold

4-Bronchitis -:

It is the inflammation of the bronchi.

Causes and symptom

  Infection microbes present in the air result in the hypertrophy ( over growth ) and hyperplasia ( an increase in the number of cells leading to hypertrophy ) of sero-mucous gland  and goblet cells ( mucous cells ) lining the bronchi. It may also be caused by cigarette smoking and exposure to air pollutants .

 Symptoms is regular coughing with thick greenish yellow sputum.

Prevention and cure
Bronchitis can be prevented by avoiding exposure to smoke, chemicals and pollutants .
Symptomatic  treatment of bronchitis disease involves intake of suitable antibiotics and also used broncho – dilator.

5- Bronchial asthma -:

It is an allergic attack of breathlessness associated with bronchial obstruction (contraction ) . This is produced by a imflammation of the bronchus .


Cause and Symptoms

Bronchial asthma is generally caused due to the hypersensitivity of the bronchioles to the foreign substance present in the air that passes through them.

Symptoms include coughing or difficulty in breathing mainly during expiration.

Prevention and cure

Best preventive measure is avoiding  exposure to the foreign substances                  ( allergens ).

     Treatment involves antibiotic therapy and use of bronchiodilator drugs / inhalers.

 6 – Pneumonia -:

It is acute infection due to inflammation of the alveoli of the lung . Alveoli , due to the accumulation of mucus in them , do not get enough air to support life.
Cause and symptoms
Pneumonia is caused mainly due to infection caused by Streptococcus_pneumoniae bacteria  Sometimes , this disease may also be caused by other bacteria, viruses and mycoplasma , fungi , protozoan etc. In such patients , the uptake of oxygen is adversely affected due to inflamed alveoli filled with excess mucus and dead WBCs.
Prevention and cure
Pneumonia can be prevented by proper and timely vaccination.
It can be cured by the use of antibiotics. Patients may take symptomatic treatment in the form of bronchiodilator drugs.

7-Emphysema -:

This respiratory disorder is due to the inflation or abnormal distension of the bronchiole or alveolar sac resulting in the loss of their elasticity.

 Causes and symptoms

Cigarette smoking and chronic Chronic Bronchitis are the causes of this disease.

     The alveolar sac remains filled with air even after expiration . Ultimately , the lung size increases.

Emphysema , Diagram of Emphysema
Prevention and cure

The disease can be prevented by avoiding exposure to cigarette smoke and pollutants. Emphysema is a chronic lung disease resulting  in irreversible distension and loss of elasticity of alveoli , it cannot be cured permanently.

         Symptomatic treatment involves use of bronchiodilator , antibiotics and oxygen therapy.

Process of Emphysema
Process of Smoking and Emphysema

8-Carbon monoxide poisoning -:

 A lamp burning in a closed room produces carbon monoxide by incomplete combustion due to shortage of oxygen .A person sleeping in such a room gets CO poisoning. CO combines with  haemoglobin far more readily than O2 , forming a relatively stable compound carboxyhemoglobin. Deficiency of oxygen causes headache , dizziness , nausea , and paralysis even death.

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