Respiratory System | Respiration – its Types
VISIT PART 1 : Lists Of Respiratory Diseases | Respiratory Disorders
VISIT PART 2 : Respiratory System | EXCHANGE OF GASES
TYPES OF RESPIRATION
#1. Anaerobic respiration :
When food is oxidized without the use of molecular oxygen, it is called anaerobic respiration. The organism undergoing this type of respiration are termed as anaerobes. Examples are anaerobic bacteria, yeasts, many parasitic animals such as Taenia, Fasciola and Ascaris. In microorganisms, this respiration is termed as fermentation and this is
termed after the name of the product they form, such as alcoholic fermentation and lactic acid fermentation.
– Alcoholic fermentation occurs in yeasts, where they oxidize glucose to ethyl alcohol and carbon dioxide
C6H12O6 —-2C2H5OH + 2CO2 + energy
– Lactic acid fermentation occurs in some bacteria where glucose is metabolized to lactic acid
– Anaerobic respiration occurs in cytoplasm and provides less energy (2ATP molecules)
– In muscles and erythrocytes, glucose is metabolized to form lactic acid which enters the blood and reaches the liver, where it is converted to glycogen aerobically for further reuse. Accumulation of lactic acid in muscles causes fatigue.
#2. Aerobic respiration :
When oxygen is used for the oxidation of food it is termed as aerobic respiration and the organisms undergoing this process are termed as aerobes. It is a high energy yielding process.
It is of two types:
a. Direct respiration: It is the exchange of environmental molecular oxygen with the carbon dioxide of the body cells without any special respiratory organ and blood. It is found in aerobic bacteria, protists, plants, sponges, coelenterates, flatworms, roundworms and most arthropods.
b. Indirect respiration: In this, exchange of gases takes place through special respiratory organs such as skin, gills, bucco-pharyngeal cavity and lungs. It needs blood for transporting oxygen and carbon dioxide after the exchange.
– The respiration through organs are termed according to their names.
Examples skin – cutaneous gills- brachial, buccopharyngeal cavity – buccopharyngeal and lung-pulmonary respiration.
– The indirect respiration occur in two phases external respiration and internal respiration. These are preceded by a preliminary phase called breathing (ventilation)
– Aerobic respiration occurs both in cytoplasm ( glycolysis) and in mitochondria (krebs cycle and electron transport chain) and provides much more energy (38 ATP molecules)
– Breathing refers to the movement that sends fresh air to the respiratory organs and remove foul air from them.
– External respiration : It is intake of oxygen by the blood from air or water in the respiratory organs and elimination of carbon dioxide.
– Internal respiration : It involves 4 process.
Uptake of oxygen by tissue cells from blood via blood tissue.
– Oxidation of food in the tissue cells by the action of oxidizing enzymes producing carbon dioxide, water and energy. This is also termed as cell respiration.
– Storage of energy from oxidation in the phosphate bonds of ATP.
– Release of carbon dioxide by tissue cells into the blood via tissue fluid.
i. It should be thin, large and moist.
ii. It should be permeable to respiratory gases.
iii. It should be highly vascular.
iv. It must be directly or indirectly in contact with the source of oxygen.
HUMAN RESPIRATORY SYSTEM
and pharynx. The lower respiratory system includes larynx, trachea, bronchi and bronchioles.
- 1. Presence of nose
2. Elongation of nasal passage and its complete separation from buccal passage through palate. So, that internal nostrils open deep into nasopharyngeal part of pharynx.
3. Long wind pipe due to presence of well defined neck
4. Spongy, solid lungs
EXTERNAL NARES ( NOSTRILS)
They are a pair of slit-like opening present on the lower end of nose.
It occurs between palate and cranium. Nasal cavity is divisible into two nasal chambers by a nasal septum. Each nasal chamber has three parts.
It is a lower smaller part just above external naris which is lined by skin and bears hair as well as oil glands. Hair help in filtering out dust particles from incoming air.
b) Conditioner ( Respiratory region)
It is middle part of nasal chamber. There are three bony projections called nasal conchae or turbinates ( superior, middle, inferior) and some sinuses ( maxillary, frontal, sphenoid and ethmoid)
– The conditioner part is reddish pinkish in coloured by ciliated pseudostratified
columnar epithelium with mucous and serous glands. The inhaled air is
moistened warned and cleaned.
c) Olfactory region
Upper part of nasal chamber and superior nasal concha are yellowish brown. They are covered by olfactory epithelium which perceives sensation of smell.
INTERNAL NARES ( CHOANAE)
The two nasal chambers open into nasopharynx through internal nares or choanac.
.Nasopharynx occurs at the base of skill and has lining of ciliated stratified squamous epithelium.
cartilages and a pair of nodule like cartilages of santorini ( upper end of arytenoids cartilages). Internally larynx has ciliated columnar mucous epithelium and a pair of vocal
cord ( attached to thyroid and arytenoids cartilages).
tips and nasal cavity.
TRACHEA ( WIND PIPE)
and lined by ciliated pseudostratified mucous epithelium.
Infection of right lung is more common due to this.
mucus secreting pseudostratified epithelium and supported by incomplete cartilaginous rings.
Abdominal muscles: Relaxation allows compression of abdominal organs when diaphragm straightens. Contraction presses the abdominal viscera against diaphragm to bulge it more
upwardly ( for expiration).
MECHANISM OF BREATHING
i. Diaphragm: When relaxed the diaphragm is dome-shaped structure which separates the thoracic cavity from the abdominal cavity. Phrenic or radial muscles extened from diaphragm to ribs and vertebral column. When these muscles contract diaphragm becomes flat, thus increases the thoracic cavity antero posteriorly. These are the principle inspiratory muscles and play about 75% role in inspiration, other muscles play 25% role in inspiration.
ii. External intercoastal muscles: They occur between the ribs. These are 11 pairs of muscles extending between 12 pairs of ribs. Their contraction pulls the ribs and sternum upward and outward there by increasing the thoracic cavity dorso-ventrally and laterally.
iii. Abdominal muscles: These muscles relax and allow compression of abdominal organs by diaphragm.
i. Diaphragm: When muscles of diaphragm relax it again becomes dome-shaped, decreasing the thoracic cavity.
ii. External intercoastal muscles: When these muscles relax, sternum and ribs come to their original position. This also decreases thoracic cavity.
iii. Abdominal muscles: Contraction of abdominal muscles presses the abdominal viscera against the diaphragm, bulging it further upward and thus decreasing the thoracic cavity more vertically.
iv. Internal intercoastal muscles: Contraction of these muscles moves the ribs downward and inward and reduces the thoracic cavity laterally and dorsoventrally. The abdominal and external intercoastal muscles are called expiratory muscles.
PULMONARY AIR VOLUMES AND CAPACITIES
The graph showing the changes in the pulmonary volumes and capacities under different conditions of birthing is called spirogram.
VC = T.V. + I.R.V. + E.R.V.
It is 3.5 to 4.5 litres
i. The vital capacity is higher in athletes mountaineers or mountain – dwellers and lower in non-athletes, people living in plains, women, old individuals, cigarette smoker.
ii. Higher the vital capacity, higher is the amount of air exchanged in each breath.
IC = T.V. + I.R.V
It is 2.5 to 3.0 litres
EC = T.V. + E.R.V
Its value is 1.5 to 1.6 litres
Functional residual capacity (FRC) : It is the sum total o residual volume and the expiratory reserve volume.
F.R.C. = R.V. + E.R.V.
Its value is 2.3 to 2.7 litre
Total lung capacity (TLC) : It is the total amount of air present in the lungs and the respiratory passage after maximum inspiration. It is the sum total of vital capacity and residual volume.
TLC = VC + RV or TLC = TV +IRY + ERV + RV
Its value is 5 to 6 litre
– Alveolar ventilation : It is the rate at which the fresh air reaches the alveoli and adjoining areas like alveolar ducts, alveolar sacs and respiratory bronchioles. It is calculated as.
– Alveolar ventilation per minute
= Rate of respiration × (TV – dead space volume)
= 12 × (500 – 150)
= 12 × 350
= 4.2 litres / minute