Respiration in Lower Animals

Subject 

Biology

Topic 

Respiration in Lower Animals

Class :

SSS 2

Term :

First Term

Week :

Week 6

Instructional Teaching Materials :

• Photos of plants and animals
• Sample alimentary canal of animal

Reference 

• Scheme of Work
• On-line Information
• Textbooks
• Workbooks

Earlier Tutorials 

The pupils have earlier information on

RESPIRATORY SYSTEMS: TYPES OF RESPIRATORY SYSTEMS

that was beforehand taught as a topic before this specific lesson

Behavioural Objectives :  On the conclusion  of this lesson, the learners will likely be able to

• Say the types of respiration in lower animals
• mention the organs of respiration in lower animals
• explain the mechanism of breathing in lower animals
• Describe the mechanism of breathing in mammals.
• Describe the mechanism of breathing in insects.
• Describe the mechanism of breathing in fish.

Respiration in Insects

The mechanism of breathing in insects is as follows:

1. An insect breathes through a trachea system. An insect has an impermeable cuticle but, at intervals along the sides of its body, are about ten tiny openings called spiracles, through which air enters and leaves the trachea.
2. These lead into air-filled tubes called tracheae which end in very hair-like, tiny structures in tissues called tracheoles. Hence, no body cell is far from a tracheole which contains certain fluids.
3. As the body wall of an insect contracts and expands, oxygen in the air diffuses through the spiracle into the trachea and tracheole. It then diffuses into the body cells where it is used for aerobic respiration.
4. Carbon (iv) oxide and water (water vapour) produced, diffuse out of the body through the spiracles.
5. The spiracles have valves and they are opened only when the carbon (iv) oxide concentration in the tissues is above a specific level.
6. The spiracles are closed for most of the time when an insect is inactive to reduce water loss.

[mediator_tech]

Evaluation

1. An insect breathes through a system called ___________.
a) lungs
b) gills
c) trachea

2. The tiny openings along the sides of an insect’s body are called ___________.
a) pores
b) spiracles
c) nostrils

3. Air enters and leaves the trachea through the ___________.
a) pores
b) spiracles
c) tubes

4. The air-filled tubes in the insect’s body are called ___________.
a) bronchi
b) tracheae
c) alveoli

5. The hair-like structures in tissues that tracheae end in are called ___________.
a) bronchioles
b) alveoli
c) tracheoles

6. Oxygen from the air diffuses into the ___________.
a) spiracles
b) tracheae
c) tracheoles

7. The fluid-containing structures that are close to body cells in insects are ___________.
a) bronchioles
b) tracheoles
c) alveoli

8. The process where oxygen enters the body cells for aerobic respiration is ___________.
a) osmosis
b) diffusion
c) filtration

9. Carbon (IV) oxide and water vapor leave the body through the ___________.
a) spiracles
b) tracheae
c) alveoli

10. The spiracles are opened only when ___________.
a) oxygen concentration is high
b) carbon (IV) oxide concentration is high
c) insect is inactive

11. Inactive insects keep their spiracles closed mainly to reduce ___________.
a) oxygen intake
b) water loss
c) carbon (IV) oxide production

12. The main purpose of the tracheal system is ___________.
a) to transport blood
b) to aid digestion
c) to facilitate respiration

13. Tracheoles contain ___________.
a) blood cells
b) fluids
c) neurons

14. Oxygen diffuses from spiracles to tracheoles and then to ___________.
a) body cells
b) brain cells
c) digestive cells

15. The breathing mechanism in insects is known as ___________ respiration.
a) aerobic
b) anaerobic
c) cellular

What is Respiration?

Mechanism of Breathing in Fish

1. Gaseous exchange or breathing in fishes occurs across the gill surfaces. All the gills possess a very high surface area-to-volume ratio.
2. The fish opens its mouth, and water passes over the gill surface inside the opercula which are then closed.
3. As water flows over the gills, the dissolved oxygen in the water diffuses into the thin walled blood capillaries of the gills. At the same time, carbon (iv) oxide in the blood diffuses into the water.
4. The alternate opening and closing of the mouth and operculum allow a constant flow of water over the gills.
5. Oxygen is transported by the blood into every living cell where it is used for aerobic respiration. Hence, the gills are used for gas exchange (breathing) and not just for respiration.

[mediator_tech]

Evaluation

1. Gaseous exchange in fish occurs across the ___________.
a) skin
b) lungs
c) gill surfaces

2. The gills of fish possess a high ___________ ratio.
a) weight-to-size
b) surface area-to-volume
c) length-to-width

3. Fish open their mouths to allow water to pass over the ___________.
a) skin
b) lungs
c) gill surface

4. Water flows over the gills inside the ___________.
a) scales
b) fins
c) opercula

5. Dissolved oxygen in the water diffuses into the ___________ of the gills.
a) scales
b) blood capillaries
c) opercula

6. Carbon (IV) oxide in the blood diffuses into the ___________.
a) water
b) gills
c) lungs

7. The alternating opening and closing of the mouth and operculum maintain a constant flow of water over the ___________.
a) skin
b) lungs
c) gills

8. Oxygen transported by the blood is used for ___________ respiration.
a) anaerobic
b) aerobic
c) cellular

9. The main purpose of fish gills is ___________ exchange.
a) heat
b) gas
c) waste

10. Fish gills are responsible for the exchange of both ___________ and carbon (IV) oxide.
a) oxygen
b) nitrogen
c) hydrogen

11. The process of breathing in fish involves the exchange of ___________ between water and blood.
a) glucose
b) oxygen
c) hormones

12. Oxygen diffuses from water into the ___________ of the gills.
a) scales
b) skin
c) blood capillaries

13. Carbon (IV) oxide diffuses from blood into the ___________.
a) water
b) scales
c) opercula

14. The fish’s gill mechanism ensures a continuous supply of ___________ to the gills.
a) food
b) light
c) water

15. Gills in fish are specialized organs for ___________ exchange.
a) respiratory
b) reproductive
c) circulatory

Organs of Breathing

Gaseous Exchange in Plants

As you learnt earlier, plants do not breathe like mammals, but like animals, they exchange gases because they do not have thorax and lungs like mammals, we cannot see their breathing movements which are the visible signs of gas exchange. Completely submerged aquatic plants (e.g. algae) or those floating on water surface (e.g. lettuce) exchange gases by diffusion all over their body surface or through the stomata in their leaves, lenticels in their stem, and through the roots (i.e.from the air spaces in the soil particles around the roots).

Anatomy of a Leaf

The leaf provides food for the rest of the plant through the process of photosynthesis. The outermost layer of the leaf is the epidermis, which is protected by the waxy coating of the cuticle. Guard cells implanted in the epidermis form pores, known as stomata, through which water, oxygen, and carbon dioxide pass. Embedded in the inner tissues of the leaf are chloroplasts, where photosynthesis occurs. The plant veins consist of two specialized tissues. Xylem conducts water from the plant to the leaf, while phloem carries food from the leaf to the plant.

They also occur in the stems of young herbaceous plants. A stoma (stomata-plural) is a tiny pore or opening enclosed by two bean-shaped guard cells. Unlike other epidermal cells, guard cells have chloroplasts. Each guard cell has a thick, relatively inelastic wall around the pore and a thin, elastic outer wall. The mechanism of the opening and closing of stomata is believed to be associated with light intensity and the osmotic pressure within the guard cells. When the osmotic pressure in the guard cells is high, they become turgid as a result of which the pore or stoma opens. When the pressure is low, the guard cells become flaccid and the stoma is closed. In general, the movement of gases and water vapour into and out of leaves is controlled by the opening and closing of the stomata.

The Effect of Light on Gas Exchange in the Leaf

Respiration occurs at all times in living things. During sunlight, the rate of photosynthesis is usually greater than that of respiration in green plants. Oxygen given out during photosynthesis in the day is captured by animals and man for respiration. Also, the carbon (iv) oxide produced by respiring cells is used in photosynthesis, while a lot of carbon (iv) oxide diffuses into the leaf mesophyll cells from outside. The diffusion from the inside of the leaf to the outside is short. Hence, gaseous molecules diffuse rapidly in and out of the leaf through the stomata.

However, at night, photosynthesis stops just as the sun stops shining, but respiration continues because animals must live. Then, some oxygen diffuses into the leaf from outside through the stomata and lenticels. The oxygen is used up in the respiring cells, while the carbon (iv) oxide diffuses out of the leaf and lenticels.

It is worthy to note that the vein of leaves contain vascular tissue. Water and mineral salts and some dissolved gases are distributed to the leaf parts through the xylem. Also, the manufactured food in the leaves is conducted through the phloem in the veins to all parts of the leaves and other plant parts.

Presentation

The topic is obtainable step-by-step

Step 1:

The subject instructor revises the sooner issues

Step 2.

He introduces the topic new topic

Step 3:

The class coach permits the pupils to current their very personal examples and he corrects them when the desires come up

Mechanism of Breathing in Mammals: Mammals, including humans, breathe through a complex system involving the respiratory tract. Air is inhaled through the nostrils, passes through the nasal passages, and reaches the trachea. The trachea then branches into two bronchi, each of which leads to a lung. Within the lungs, the bronchi further divide into smaller bronchioles, culminating in tiny air sacs called alveoli. During inhalation, the diaphragm and intercostal muscles contract, expanding the chest cavity. This creates a negative pressure that draws air into the lungs. In the alveoli, oxygen diffuses into the bloodstream, binding to hemoglobin in red blood cells. Simultaneously, carbon dioxide, a waste product of cellular respiration, diffuses out of the blood into the alveoli to be exhaled during exhalation. Exhalation is a passive process, where the diaphragm and intercostal muscles relax, reducing the volume of the chest cavity and forcing air out.

Mechanism of Breathing in Insects: Insects breathe through a network of tubes called the tracheal system. Tiny openings called spiracles are present along the insect’s body, through which air enters and leaves. The spiracles lead to air-filled tubes called tracheae. These tracheae branch into smaller tracheoles, which come into close contact with body cells. Oxygen from the air diffuses through spiracles, tracheae, and tracheoles to reach body cells, where it’s used for respiration. Carbon dioxide and water vapor, products of respiration, diffuse out of cells and follow the reverse path to exit the body through the spiracles. The opening and closing of spiracles are regulated to control gas exchange and limit water loss, especially during periods of inactivity.

Mechanism of Breathing in Fish: Fish respire using gills, which are specialized structures for underwater breathing. Water enters the fish’s mouth and flows over the gills. Gills are composed of filaments with thin walls and a rich network of blood vessels. As water passes over the gill filaments, oxygen dissolved in the water diffuses into the blood, while carbon dioxide diffuses out of the blood into the water. This exchange of gases occurs across the gill membranes due to the difference in oxygen and carbon dioxide concentrations between water and blood. The fish’s mouth opens and closes, and the opercula (bony plates covering the gills) help create a continuous flow of water over the gills, ensuring a constant supply of oxygen. The oxygenated blood is then distributed throughout the fish’s body to fuel cellular respiration

Conclusion :

The class coach wraps up or conclude the lesson by giving out temporary observe to summarize the topic that he or she has merely taught.

The class coach moreover goes spherical to ensure that the notes are correctly copied or correctly written by the pupils.

He or she does the required corrections when and the place  the desires come up.

EVALUATION

1. Describe the mechanism of breathing in mammals.
2. Describe the mechanism of breathing in insects.
3. Describe the mechanism of breathing in fish.

Conclusion 

The topic wraps up the subject by giving the learners a complete notice and she or he makes certain that the learners copy the notes accurately . She or he marks the notes and he does the mandatory corrections