The document provides an overview of the respiration process, detailing the distinction between breathing and cellular respiration, which includes aerobic and anaerobic pathways. It explains the human respiratory system, including its structure, function, and the mechanics of breathing, as well as the roles of various organs such as the lungs, trachea, and diaphragm. Additionally, it covers the biochemical aspects of respiration, such as the role of mitochondria in energy production and the significance of pulmonary surfactant for lung function.

2. Respiration
Process which involves taking in oxygen into the cells, using it
for releasing energy by burning food and then eliminating
the waste products like carbon dioxide and water from the
body
It is a catabolic process as the food
is broken down into simpler form. In short, respiration is a
biochemical activity taking place with in the protoplasm of
the cell and results in the liberation of energy

3. Breathing and Respiration
BREATHING
1. Mechanism by which
organisms obtain oxygen
from the air and release
carbon dioxide
2. It is a physical process
3. It involves lungs of the
organism
RESPIRATION
1. It includes breathing and
oxidation of food in the cells
of the organism to release
energy
2. It is a biochemical process
3. It involves the mitochondria
in the cells where food is
oxidized to release energy

4. Types of respiration
Aerobicrespiration Anaerobicrespiration
1. Oxygen is required
2. Such organisms are called aerobes
3. Occurs in mitochondria
4. Involves the process of glycolysis
where glucose is broken down to
pyruvic acid
5. Pyruvate is converted to CO2, water
and energy by Krebs cycle
C6H12O6 + 6O2 6CO2 + 6H2O +
energy
6. 38 ATP is generated
7. Occurs in all higher organisms
1. Oxygen is not required
2. Process is called anaerobiosis
3. It invovles the process of glycolysis in the
cytoplasm.
4. It is the metabolic pathway that
converts glucose C6H12O6, into pyruvate
CH3COCOO− + H+.
1. The free energy released in this process is
used to form the high-energy molecules
ATP and NADH .
2. Pyruvate then enters different pathways
and forms different products
3. Generally found in micro organisms ,
yeast and parasitic worms (prokaryotes)

6. Fermentation - Anaerobic breakdown of carbohydrates and other
organic compounds into alcohol, organic acids, gases etc .
When alcohol is produced it is called alcoholic fermentation
e.g. Yeast
C6H12O6 fermentation 2C2H5OH + 2CO2 + Energy
C2H5OH ( acetobacter aceti) CH3COOH + H2O
(Ethanol) (Acetic acid)
Acetobacter aceti is used in the production of vinegar by
converting the ethanol in wine into acetic acid.

7. When lactic acid is produced as an end product then it is called
lactic acid fermentation e.g. Bacteria and parasitic worms
e.g. C6H12O6 2CH3CHOHCOOH + energy
(glucose) (lactic acid)
( The anaerobic respiration in human muscle tissue produces
lactic acid as an end product during vigorous physical exercise)

8. Types of aerobic respiration
Direct respiration
1. It is the exchange of oxygen
(of air) with CO2 of the body
cells
2. Without special respiratory
organs or blood e.g. aerobic
bacteria, plants, sponges
1. In this type special
respiratory organs like
skin, buccopharyngeal
lining, gills, and lungs
are used
2. It also involves the
blood
Indirect respiration

9. Cutaneous Respiration- Respiration in which skin is used
e.g. annelids, amphibians
Buccopharnygeal respiration- Respiration in which
buccopharyngeal lining is involved e.g. Frog, toad
Branchial respiration- It is exhibited by many annelids, most
crustaceans, molluscs and all fishes

10. Types of indirect respiration
External respiration
1. A physical process in which
an organism takes in oxygen
and gives out CO2
2. May involve respiratory
surface such as
integument,gills,trachea or
lungs
3. E.g. gas exchange between air
in the alveoli and blood in
pulmonary capillaries
Internal respiration
1. Also called tissue
respiration
2. Food is broken down into
simpler molecules within
the cells and energy is
produced
3. E.g. gas exchange between
tissue cells and the blood in
systemic capillaries

11. Human respiratory systemIt is chiefly divided into two components:
1. Respiratory tract
2. Respiratory organ
Respiratory Tract- A passage which allows movement of inspired
and expired air in and out of the lungs. It consists of
1. Nostrils
2. Nasal chambers
3. Internal nares
4. Pharynx
5. Larynx
6. Trachea

12. Human Respiratory System

13. 1. Nostrils-The two nostrils are the openings of the nasal cavity
and lie above the mouth . They are separated by the septum
2. Nasal chambers- A pair of passages in the head above the
palate. They are separated from each other by a septum.
Each nasal chamber is divided into three regions:
1. Vestibular region
2. Respiratory region
3. Olfactory region

14. • Vestibular region- Lies within the external naris, short and lined by
hairy skin. Acts as a filter and prevents the entry of dust particles.
• Respiratory region- The middle region lined with respiratory
epithelium. Ciliated and rich in mucous glands.
• Olfactory region- The upper region of the nasal chamber, lined
with olfactory epithelium. Acts as an organ of smell.

15. 3. Internal Nares-Openings of nasal chambers in the roof of
nasopharynx and are closed by uvula during swallowing.
4. Pharynx-. The pharynx (plural: pharynges) is the part of
the throat that is behind the mouth and nasal
cavity and above the esophagus and the larynx ( the
tubes going down to the stomach and the lungs)
A short vertical approx. 12cm long tube behind the buccal
cavity
It is divided into three parts:
1. Nasopharynx
2. Oropharynx
3. Larngyopharynx

17. Nasopharynx- Upper part of pharynx extends from the base of
the skull to the upper surface of the soft palate
Oropharynx- Middle part of pharynx in front of the buccal cavity
Laryngyopharynx- Lower part of pharynx, leads into two tubes the
trachea and the esophagus
5. Larynx- Often called Adam’s apple. More prominent in men than
in women
A cartilaginous box helps in sound production hence called sound
box . Enlarged upper end of the trachea situated in the neck on the
level of the 4th to the 6th cervical vertebrae.
Open into laryngopharynx by a slit like aperture called glottis
The glottis bears a leaf like cartilaginous flap called the epiglottis

19. 6. Trachea- or windpipe is approx 4 inches long, extends from
larynx to the middle of thoracic cavity where it divides into to
bronchi (the right and left primary bronchi)
• One major branch enters each lung. The right primary bronchus
divides into the secondary bronchi, which extends into two lobes of
the left lung.
• The secondary bronchi subdivides into smaller tertiary bronchi
and further into still smaller bronchioles.
• The small terminal bronchioles give off the respiratory bronchioles
which divide into alveolar ducts
This is called bronchial tree
The bronchial tree

20. The respiratory organs
• The main respiratory organs are a pair of lungs
• The branching network of bronchi, bronchioles and alveoli
comprise the lungs
• The lungs are two in number, fill the chest cavity lying one on each
side separated in the middle by heart
• Lungs are covered by a double layered pleura with pleural fluid in
between them
• This fluid acts as a lubricant permitting the lungs to move freely in
the thoracic cavity during breathing

21. Mediastinum- It is the space in the thoracic cavity between the two
lungs .It includes pleura of both the sides
The thoraciccavity- It is a hollow cavity and has two pleural
cavities each enclosing a lung
It is barrel shaped bounded at the back by backbone and
at the front by breast bone.
The sides are formed by the ribs
Diaphragm- A sheet of skeletal muscles, dome shaped muscular
partition separating thorax from abdomen anteriorly at rest and
attached to the lumber vertebrae and posteriorly to ribs performs
an important role in respiration

22. External features of lungs
Lungs are soft spongy
elastic organs with
smooth shiny surface
marked into numerous
polyhedral areas
Conical in shape having
a narrow apex at the
upper end and broad
concave base on
lower end

23. Lungs are divided into lobes by fissures
The right lung has three lobes while the left lung has two lobes
Each of these lobes is composed of a number of lobules
Lungs consist of bronchioles and alveoli and an extensive network of
blood vessels and the capillaries
The walls of the air sacs or alveoli are elastic and supplied with
capillaries from the pulmonary artery and are kept moist by
secretions to allow gases to diffuse.
It is done by the fluid produced by the walls of the alveoli
The surface tension of this fluid must be low else the alveoli may not
expand when air is inhaled
The fluid therefore contains a surfactant ( a detergent like substance)
to reduce surface tension

24. Pulmonary surfactants
Pulmonary surfactant is a mixture of lipids and proteins which is
secreted into the alveolar space by epithelial type II cells. The
main function of surfactant is to lower the surface tension at the
air/liquid boundary within the alveoli of the lung through
hydrophilic and hydrophobic forces.
Insufficient pulmonary surfactant in the alveoli can contribute to
collapse of part or all of the lung(atelectasis)

25. HUMAN LUNGS

26. In trachea and bronchi the goblet cells of the ciliated epithelium
produce the mucus.
It is a slimy solution containing glycoprotein's
glycoprotein's are able to trap inhaled particles e.g. pathogens
and dust
Chemical pollutants such as SO2 can dissolve in the mucus to
form an acidic solution that irritates the airways
The nasal passages have tiny hairs lining them as well
macrophages, phagocytic WBC’s patrol the surface of the air ways
remove particles such as bacteria

27. Mechanism of breathing
When we breathe in and out the chest goes up and down
This happens when
• We inhale the ribs move upward and outward
• Chest becomes bigger
• When we exhale , the ribs move downwards and inwards
• Chest becomes smaller
Lungs are present in the chest cavity
The ribs surround this cavity on the sides
A large muscle called diaphragm forms the floor of the chest cavity

28. During inhalation
• Ribs move out
• Diaphragm moves down
• Making the chest cavity bigger
• Air then rushes into the lungs and they inflate
During exhalation
• Ribs move downwards and inwards
• Diaphragm moves up
• Chest cavity is reduced
• Air rushes out of the lungs
• And the lungs grow smaller

29. THANK YOU
PREPARED BY
RITU.S