Respiratory System

Back to: AGRICULTURAL SCIENCE SS1

 

Welcome to class! 

In today’s class, we will be talking about the respiratory system. Enjoy the class!

Respiratory System

The respiratory system includes all the organs and tissues associated with the exchange of gases between the animal and its environment, leading to the release of energy. The purpose of respiration is to supply oxygen to the cell which burns down food to release energy.

C₆H₁₂O₆       +        6O₂              à      6CO₂           +        6H₂O +        ENERGY

^{(Glucose)                                  (Oxygen)                           (Carbon dioxide)                  (Water)                  (ATP)}

Types of respiration

1. Aerobic respiration: This is the type of respiration that takes place in the presence of oxygen.

C₆ H₁₂ O₆ +        6O₂              à      6CO₂           +        6H₂O +            ENERGY

          ^{(Glucose)                                (Oxygen)                           (Carbon dioxide)                        (Water)             (ATP)}

2. Anaerobic respiration: This is the type of respiration that takes place in the absence of oxygen. Anaerobic respiration is also known as fermentation.

C₆H₁₂O₆            à      2C₂H₅OH               +       2CO₂           +        ENERGY

                ^{(Glucose)                              (Alcohol)                                      (Carbon dioxide)                              (ATP)}

Respiratory organs

This refers to an organ such as the lungs in land animals and gills in aquatic animals.

Land animals use lungs for respiration. Other organs that aid respiration in land animals are the nostrils (two external openings of the nasal cavity in vertebrates that admit air to the lungs), pharynx, Larynx (situated just below where the tract of the pharynx splits into the trachea and the oesophagus). The trachea (windpipe) is a cartilaginous tube that connects the pharynx and larynx to the lungs, allowing the passage of air, and so is present in almost all air-breathing animals with lungs. The trachea extends from the larynx and branches into the two primary bronchi.

Epiglottis disallows entrance of food particles into the trachea. bronchi is a passage of airway in the respiratory system that conducts air into the lungs. The bronchioles or bronchioli are the passageways by which air passes through the nose or mouth to the alveoli (air sacs) of the lung. Alveoli are tiny sacs within the lungs that allow oxygen and carbon dioxide to move between the lungs and bloodstream.

Process of breathing

The breathing process is an activity that takes place consciously or not, the process of breathing moves air in and out of the lungs. Inward movement of air is called inhalation while exhalation is the outward movement of air from the animal body.

 

Aquatic animals use gills which are located on both sides of the head region for respiration. The gills are in threes or fours arranged in the gill chamber. Each gill consists of a gill filament where gaseous exchange takes place, gill raker that prevents particles from entering the gill chamber, gill arch on which the gill filament is built. The gill chamber is closed externally by an operculum.

Diagram of fish gill

Evaluation 

1. Describe the process of inhalation and exhalation.
2. Differentiate between the two types of respiration.

Importance of the respiratory system

1. Supplies oxygen to the body cells
2. It reduces heat load in the body, especially in poultry.
3. Removes carbon dioxide from the body
4. Promotes gaseous exchange

Evaluation

1. Define Respiration.
2. List and explain the two types of respiration.
3. How does fish respire in the water?
4. Represent Aerobic Respiration in the chemical equation
5. Describe the process of respiration in a named animal?

Reading assignment

• Essential Agricultural Science for Senior Secondary Schools by O.A. Iwena chapter 29 page 272 – 274
• Essential Biology for Senior Secondary Schools by M. C. Micheal page 248 – 258

Nervous system

The nervous system includes all the organs and tissues which enable farm animals to respond to changes in their environment. The change in the environment is called stimulus and the reaction of the living things to the stimulus is the response. The nervous system is made up of two parts;

• Central Nervous System: This includes the brain and the spinal cord. Both are made up of thousands of nerves and neurons. The functions of C.N.S. are a correlation of impulses from various sense organs and storage of impulses as information.
• Peripheral Nervous System: This consists of cranial and spinal nerves. The P.N.S. mediates between animals and their external environment.

General evaluation

1. Write brief notes on a) Respiratory system b) Nervous  system
2. Distinguish between the central nervous system and peripheral nervous system.

Reading assignment

• Essential Agricultural Science for Senior Secondary Schools by O.A. Iwena chapter 29 page 274 – 276
• Essential Biology for Senior Secondary Schools by M. C. Micheal page 313 – 324
• Answer the following questions from WAEC PAQ 1994 theory question 8

 Theory

Describe briefly a simple reflex action in animals and state four examples

 

In our next class, we will be talking about Reproduction in Farm Animals.  We hope you enjoyed the class.

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