Respiration Overview and Types

Respiration Overview

• Respiration is a process where energy is released by breaking down food.
• The chemical equation for respiration is: C₆H₁₂O₆ + 6O₂ → 6CO₂ + 6H₂O + 686 kcal/mole
• Energy liberated is in the form of ATP (adenosine triphosphate).
• Life activities requiring energy include moving and caring for young ones.

Types of Respiration

• Aerobic Respiration: Occurs in animals using oxygen, the normal respiration process.
• Anaerobic Respiration: Occurs in the absence of oxygen, like in tapeworms.
  • Can happen temporarily in muscles during strenuous exercise due to insufficient oxygen.
  • Results in lactic acid formation, causing fatigue.
  • Oxygen debt is cleared when resting after exercise.

Glucose and Respiration

• Glucose is the primary energy source for respiration.
• If glucose is unavailable, the body can break down proteins or fats.
  • Wild animals mainly use protein for energy.
  • Humans break down excess protein into glucose and urea.

Chemical Steps in Respiration

• Aerobic respiration involves the same chemical changes in animals and plants.
• The overall reaction releases 686 kcal/mole when 180g of glucose is broken down.

Parts of Respiration

• Breathing: The physical process of inhaling and exhaling air.
• Gaseous Transport: Oxygen is carried by red blood cells as oxyhemoglobin, and carbon dioxide is transported to the lungs in blood as bicarbonates and carbaminohemoglobin.
• Tissue Respiration: Oxygen is delivered to body tissues, and carbon dioxide is absorbed from cells.
• Cellular Respiration: Complex chemical changes occur inside cells to release energy from glucose.

Anaerobic Respiration in Plants and Animals

Anaerobic Respiration in Animals

• Occurs in skeletal muscle cells during strenuous exercise.
• Glucose breaks down into lactic acid, producing 2 ATP and heat energy.
• The process is slow and cannot continue for long due to lactic acid toxicity.
• No CO₂ is produced, and significantly less energy is released compared to aerobic respiration.

Energy Release (ATP)

• Respiration releases 686 kilocalories (2890 kJ) of energy.
• The equation for energy release in the form of ATP is: C₆H₁₂O₆ → 6CO₂ + 6H₂O + 38ATP + Heat Energy

Where Does Respiration Occur in a Cell?

• Glycolysis (CYTOPLASM): Breakdown of glucose into pyruvic acid, releasing minimal energy.
• Krebs Cycle (MITOCHONDRION): Breakdown of pyruvic acid to produce ATP and CO₂, requiring oxygen and producing more energy.

The Respiratory System

• Composed of air passages, lungs, nose, pharynx, larynx, trachea, and bronchi.

Nose:

• Contains nostrils, hairs, and a lining for warming, moisturizing, and trapping particles.

Pharynx:

• Common passage for air and food, situated behind the mouth.

Larynx:

• Voice box at the start of the trachea, with cartilaginous structure (Adam's apple).

Lungs

• Pair of elastic organs covered by two membranes (visceral and parietal pleura).
• Cone-shaped, broader at the bottom and tapering at the top.
• The left lung has two lobes, and the right lung has three.
• Fill the thoracic cavity, resting on the diaphragm.

Alveoli

• Tiny air sacs in the lungs with thin walls for efficient gas exchange.

Gas Exchange

• Oxygen diffuses from alveoli into blood capillaries.
• Carbon dioxide diffuses from blood into alveoli to be exhaled.

Blood Circulation

• Deoxygenated blood enters the lungs via the pulmonary artery.
• Oxygenated blood returns to the heart via pulmonary veins.

Respiratory Passages

• Inner lining of the larynx, trachea, bronchi, and bronchioles is made of ciliated epithelium.
• Cilia move mucus and trapped particles upward towards the mouth.
• Goblet cells produce mucus to trap dust particles and bacteria.

Breathing and Respiratory Cycle

• Respiration is a broader term including breathing.
• Breathing is the process of inhaling and exhaling air.
• The respiratory cycle involves inspiration, expiration, and a short pause.

Inspiration (Inhalation)

• Increase in thoracic cavity size achieved by the action of ribs and diaphragm.
• Ribs: External intercostal muscles contract, pulling ribs upwards and outwards.
• Diaphragm: Contracts, flattening from a dome shape, increasing chest cavity volume.
• Decreased pressure inside the lungs causes air to rush in to equalize pressure.

Expiration (Exhalation)

• Relaxation of rib muscles and diaphragm.
• Ribs: External intercostal muscles relax, ribs move downwards and inwards.
• Diaphragm: Relaxes, returning to a dome shape, decreasing chest cavity volume.
• Increased pressure inside the lungs pushes air out.

Tissue or Internal Respiration

• Cells use oxygen to oxidize food for energy, releasing carbon dioxide as a byproduct.

Breathing Mechanisms

Inhalation:

• Ribs elevate, expanding the chest cavity.
• Diaphragm contracts and moves downwards.
• Decreased pressure inside the lungs draws air in.

Exhalation:

• Ribs depress, decreasing the chest cavity volume.
• Diaphragm relaxes and moves upwards.
• Increased pressure inside the lungs forces air out.

Control of Breathing Movements

• Breathing is controlled by the respiratory centre in the brain.

Lung Capacities

• Tidal Volume: Air breathed in and out normally (500 ml).
  • Dead Air Space (150 ml): Tidal air remaining in respiratory passages.
  • Alveolar Air (350 ml): Tidal air within air sacs.
• Inspiratory Reserve Volume: Forcibly inhaled air beyond tidal volume (3000 ml).
• Inspiratory Capacity: Total volume of air a person can breathe in after normal exhalation (3500 ml).
• Expiratory Reserve Volume: Forcibly exhaled air after normal expiration (1000 ml).
• Vital Capacity: Maximum volume of air a person can take in and expel (4500 ml).
• Residual Volume: Air remaining in the lungs after maximum exhalation (1500 ml).
• Total Lung Capacity: Maximum amount of air lungs can hold (6000 ml).

Inspired Air vs.Expired Air

• Expired air contains less oxygen, more carbon dioxide, more water vapor, and is warmer.

Hypoxia and Asphyxia

• Hypoxia: Oxygen deficiency in tissues, can happen in poorly ventilated rooms or at high altitudes.
• Asphyxia: Condition where blood becomes more venous due to carbon dioxide accumulation.

Experiments on Respiration

Diaphragm Action:

• Rubber sheet represents the diaphragm.
• Pulling the sheet down increases volume and decreases pressure, causing air intake.
• Pushing the sheet up decreases volume and increases pressure, pushing air out.

Expired Air Volume:

• Measure water displacement in a tube to determine exhaled air volume.

Oxygen Uptake in Animals:

• Live cockroach consumes oxygen faster than a dead one, causing a candle flame to extinguish quicker.

Plant Respiration

• No external ventilation.
• No special gas transport.
• Anaerobic respiration in some plants.
• Green plants produce little CO₂.
• Additional gas exchange in green plants.

Inspired Air vs.Expired Air (Detailed)

Effect of Altitude on Breathing

• As altitude increases, air pressure and oxygen content decrease.
• Air sickness can occur at around 4,500 meters.

Experiments on Breathing

Water Loss During Breathing:

• Breathe on a cold surface to demonstrate water condensation from exhaled air.

Carbon Dioxide Release During Breathing:

• Exhaling into lime water turns it milky faster than inhaled air, indicating more carbon dioxide.

This quiz covers the essential concepts of respiration, including aerobic and anaerobic processes. It highlights how energy is released from food, the role of glucose, and the effects of oxygen availability on respiration. Understand key terms and principles related to energy production in living organisms.