Frank Brothers Solutions for ICSE Class 9 Biology Chapter 19 Respiratory System

PAGE NO:176

Solution 1:
Respiration: It is a process of release of energy from food substances such as glucose and fats under the control of enzymes, to carry out life processes, by the living organisms. Respiration is essential for life as energy produced during this process is utilized by the organisms to carry out various biological activities.

Respiration happens inside every cell of your body to turn the food you eat into power. This process requires oxygen and produces carbon dioxide as a waste product.
Teacher's Tip: Think of respiration as a tiny power plant inside your body.
Exam Tip: Make sure to mention that enzymes control this process to get full marks.

Solution 2:
Structure of nasal chamber:
The nasal chamber is divided into left and right chambers by nasal septum. Each chamber is divided into three regions -
1. Vestibule: It is the anterior most part of nasal chambers bearing hairs which filters the dust particles.
2. Respiratory region: It is rich in mucous glands and marked by nasal turbinates which traps the dust and humidify the air.
3. Olfactory chamber: It is lined by olfactory epithelium which sense the smell.

The nasal chamber acts as a gateway that cleans and warms the air before it reaches your lungs. The different regions ensure we can breathe safely and also enjoy the scent of flowers.
Teacher's Tip: Use "V-R-O" (Vestibule, Respiratory, Olfactory) to remember the sequence from front to back.
Exam Tip: Draw a simple flowchart showing the three regions to impress the examiner.

Solution 3:
Turbinates: The respiratory region of nasal chamber is marked by three nasal turbinates. These are Ethmoturbinate, nasoturbinate and maxilloturbinates.
Function of turbinates: It increases the surface area, so that dust particles can be removed and air become humidified.

These bony structures act like speed bumps that swirl the air around inside your nose. This swirling action helps to trap more dust and makes the air moist and warm.
Teacher's Tip: Turbinates are like "turbines" that spin the air for cleaning.
Exam Tip: List all three specific names of the turbinates to secure maximum marks.

Solution 4:
Adam's apple : It is a prominent elevation formed by the laminae of thyroid cartilage. It is more pronounced in male than female.

The Adam's apple is actually a part of the voice box that sticks out more in boys during puberty. It protects the front of the larynx and helps in sound production.
Teacher's Tip: Think of it as a "shield" for your voice box.
Exam Tip: Define it as the "laminae of thyroid cartilage" for a more scientific and accurate answer.

Solution 5:
Structure of Trachea: It is a long thin air tube about 11 cm long and 2.5 cm broad. Its wall is semi-transparent and composed of 4 layers-
1. Mucosa 2. Submucosa 3. Cartilaginous layer 4. Adventitia
The trachea in the thoracic region bifurcates into two short tubes called primary bronchi which enters into the lungs.
Lungs
Right main stem bronchus
Right lobes
Trachea
Apex
Left main bronchus
bronchi
Bronchioles
Left lobes
Pleura
Pleural fluid
Diaphragm
Alveoli

The trachea is often called the windpipe because it is the main tube carrying air to the lungs. Its layers are specially designed to stay open so you can breathe even when you are lying down.
Teacher's Tip: Remember "M-S-C-A" for the layers: Mucosa, Submucosa, Cartilaginous, Adventitia.
Exam Tip: When labeling the diagram, always use a ruler for straight pointing lines.

Solution 6:
The function of lecithin film in the lungs is to decrease the surface tension and keeps the alveoli open.

This thin film acts like a lubricant that prevents the tiny air sacs from sticking together. Without it, our lungs would find it very hard to expand and contract during breathing.
Teacher's Tip: Think of lecithin as "non-stick oil" for your lung's air sacs.
Exam Tip: Mention "surface tension" specifically as it is the key scientific term here.

Solution 7:
ALVEOLI OF INFANT: 1. Alveoli of infant is thin and tubular.
ALVEOLI OF ADULT: 1. Alveoli of adult is thick and sac- like.

As humans grow, their lungs develop from thin tubes into complex sac-like structures. This change allows adults to take in more oxygen to support their larger bodies.
Teacher's Tip: Infants have "tubes," and adults have "sacs."
Exam Tip: Present comparisons in a clear two-column format to make it easy for the teacher to grade.

Solution 8:
Breathing: It is the physical process of taking in oxygen and giving out carbon dioxide. The function of diaphragm: It helps in breathing by contracting and relaxing thereby increase and decrease the volume of thoracic cavity. During inspiration diaphragm flattens while during expiration it becomes dome - shaped

Breathing is the physical act of moving air in and out, while the diaphragm is the main muscle doing the work. When the diaphragm moves down, your lungs fill up like a balloon.
Teacher's Tip: Remember: Inhale = Flat diaphragm; Exhale = Dome diaphragm.
Exam Tip: Clearly distinguish between the "physical process" (breathing) and the "chemical process" (respiration).

Solution 9:
1. Cough Reflex: It is a type of reflex whose stimulus is any foreign particle which results from deep inspiration followed by strong expiration that forcefully expel the air through the mouth.
2. Sneeze Reflex: It is a type of reflex whose stimulus is in the nasal passage which causes spasmodic contraction of expiratory muscles that forcefully expel the air through the nasal passage.
3. Eupnea: Eupnea is a normal breathing.
4. Dyspnea: A condition in which breathing is painful.
5. Apnea: A condition in which no breathing takes place.

These reflexes are your body's way of clearing out irritating things from your breathing passages. The different terms like Eupnea and Apnea help doctors describe exactly how a person is breathing.
Teacher's Tip: "A-pnea" starts with A, which means "Away" or no breathing.
Exam Tip: Use the term "spasmodic contraction" when describing a sneeze to show a higher level of understanding.

Solution 10:
Internal respiration: It is the transport of oxygen in the blood from the lungs to the cells and the transport of carbon dioxide from the tissue cells into the blood and to the lungs.

While external respiration happens in the lungs, internal respiration happens throughout the entire body at the tissue level. It ensures that every single cell gets the oxygen it needs to survive.
Teacher's Tip: Internal means "inside the tissues."
Exam Tip: Mention the transport of both oxygen and carbon dioxide to provide a complete definition.

Solution 11:
Respiratory quotient (RQ): It is the ratio of CO₂ output to O₂ uptake. It is denoted by R.
R = Rate of CO₂ output / Rate of O₂ uptake
RQ for carbohydrate = 1.00
RQ for fat = 0.70
RQ for protein = 0.85

RQ is a way for scientists to see what kind of "fuel" the body is burning, like sugar or fat. Different foods produce different amounts of carbon dioxide relative to the oxygen used.
Teacher's Tip: RQ = {CO₂}/{O₂} - just remember "C" comes before "O" in the alphabet for the top and bottom.
Exam Tip: Always include the specific values for carbohydrates (1.00) and fats (0.70) in your answer.

Solution 12:
(i) Vestibule
(ii) Larynx
(iii) Alveoli
(iv) Lecithin
(v) Hyperpnea
(vi) Dyspnea
(vii) Apnea
(viii) Hypopnea
(ix) Thoracic cavity

These terms represent the key components and states of the respiratory system. Knowing these names helps you understand the map of how air travels through your body.
Teacher's Tip: Create flashcards for these one-word terms to memorize them quickly.
Exam Tip: Double-check your spelling for scientific terms like "Hyperpnea" and "Thoracic."

Solution 13:
(i) Pleura
(ii) Eupnea
(iii) 500 cc
(iv) 0.70
(v) 38 ATP

Each of these values and terms refers to a specific measurement or part of the breathing process. For example, 38 ATP is the total energy produced from one molecule of glucose during aerobic respiration.
Teacher's Tip: Remember that "Pleura" is the double-layered protective bag for your lungs.
Exam Tip: Use the correct units, like "cc" or "ATP," when writing down scientific measurements.

Solution 14:
1. Larynx = To produce voice
2. Alveoli = To increase the surface area for exchange of gases.
3. Conchae = It is also called turbinate and its function is to increase the surface area so that the dust particles can be removed and air become humidified.
4. Epiglottis = It closes the glottis during swallowing of food.
5. Lecithin covering = It lowers the surface tension and keeps the alveoli open.
6. Cartilaginous rings = It prevents the collapsing of trachea.

Each part of the respiratory system has a specialized job, from making sound to preventing choking. This teamwork ensures that the air we breathe is processed perfectly before it enters the blood.
Teacher's Tip: The Epiglottis is like a "trapdoor" that keeps food out of your lungs.
Exam Tip: Match the structure exactly to its primary function to avoid losing marks.

Solution 15:
1. Alveoli - Gaseous exchange
2. Larynx - Sound production
3. Thoracic cage - Breathing

Matching these parts to their functions helps reinforce the relationship between anatomy and physiology. It shows how the shape of an organ is designed for its specific purpose.
Teacher's Tip: Link "Alveoli" and "Exchange" because they both involve the movement of gases.
Exam Tip: Draw straight lines or write the pairs clearly side-by-side.

PAGE NO:177

Solution 16:
Larynx, trachea, primary bronchi and lungs of human
Larynx
Trachea
Apex
Parietal Pleuron
Pleural Cavity
Visceral Pleuron
Superior Lobe
Right Lung
Primary Bronchus
Fissure Horizontal
Lobe Middle
Fissure Oblique
Lobe Inferior
Superior
Left Lung Lobe
Oblique Fissure
Inferior Lobe
Cardiac Notch
Mediastinum
Base
Diaphragm

This diagram shows the entire path air takes from your throat down into the deep parts of your chest. It highlights how the tubes branch out into smaller and smaller paths like a tree.
Teacher's Tip: Think of the lungs as an "upside-down tree" where the trachea is the trunk.
Exam Tip: Practice drawing the "cardiac notch" on the left lung as it is a specific feature of human anatomy.

Solution 17:
(i) (b) Pleural membrane
(ii)( b) Alveoli
(iii) (d) All the above
(iv) (d) shows no change
(v) (d) 3000 - 4500 ml
(vi) (d) 158 and 116 mm Hg

These multiple-choice questions cover everything from the membranes protecting your lungs to the volume of air they can hold. They test your ability to recall specific facts and measurements accurately.
Teacher's Tip: For lung capacity, remember the range is usually in thousands of milliliters (ml).
Exam Tip: Read all options before picking one, as sometimes "All the above" is the correct choice.