Respiration and Energy Release

• Air is transported to all parts of the body and to each cell for respiration
• Oxygen in cells aids in the breakdown of food and releases energy
• This energy is essential for all bodily functions

Anaerobes

• Anaerobes are organisms that can respire without oxygen
• Yeast is an example of an anaerobe

Hunger After Physical Activity

• Extra energy is needed when doing a physical activity
• This results in more oxygen being supplied to cells
• The process speeds up the breakdown of food and more energy is released
• This is why we feel hungry after physical activity

Anaerobic Respiration

• In humans, anaerobic respiration occurs in muscle cells
• This happens during heavy exercise when energy demand is high, but oxygen supply is low
• Anaerobic repiration then takes place in muscle cells to fulfill the demand of energy

Relief from Muscle Cramps

• Muscle cramps occur when lactic acid builds up in muscle cells due to anaerobic respiration
• Hot water baths or massages improve blood circulation
• Better circulation increases oxygen supply to the muscle cells
• Enhanced oxygen results in the complete breakdown of lactic acid into carbon dioxide and water, relieving pain

Breathing Through the Nose

• When inhaling through your nose, air particles are trapped by hair and mucus in the nasal cavity
• This allows filtered air to enter the lungs
• Breathing through the mouth allows unfiltered air with dust to enter the lungs, potentially causing respiratory problems

Breathing vs Respiration

• Breathing is taking in oxygen-rich air and releasing carbon dioxide-rich air
• Respiration is the breakdown of food in cells, which then releases energy

Reasons

• Smoking harms the lungs and is associated with cancer
• Gills help fish use oxygen dissolved in water, and fish die when taken out of water
• Exhaled air contains carbon dioxide
• Carbon dioxide turns limewater milky by forming calcium carbonate

Rib and Diaphragm Movement

• During inhalation, ribs move up and out, and the diaphragm moves down
• This increases space in the chest cavity, allowing air to rush into the lungs, filling them
• During exhalation, ribs move down and in, and the diaphragm moves up
• This reduces the chest cavity size, pushing air out of the lungs

Breathing Rate

• Breathing rate is the number of breaths a person takes in a minute
• On average, an adult breathes 15-18 times per minute while at rest
• During heavy exercise, the breathing rate can increase up to 25 times per minute

Yawning

• When bored or tired, we don't breathe as deeply, resulting in the body taking in less oxygen
• Yawning helps bring more oxygen into the blood, increasing the respiration rate

Whales and Dolphins

• Whales and dolphins release a fountain of water when moving upward because they breathe fresh air and eject carbon dioxide

Respiratory Organs

• Fish: Gills
• Cockroach: Trachea
• Earthworm: Moist skin
• Frog: Lungs and skin

Overwatering Potted Plants

• Overwatering prevents roots from taking up air from spaces in soil particles
• This causes root decay and plant death

"Smoke" on Cold Days

• On cold days, warm, moist exhaled air condenses into vapor, resembling white smoke

Muscle Cell Respiration

• Muscle cells can respire anaerobically for a short time when there's an oxygen deficiency, such as during intense exercise
• Cramps occur when muscle cells respire anaerobically, leading to lactic acid build-up
• Relief comes from hot water baths or massages that improve circulation, increasing oxygen supply to muscle cells
• This increase in oxygen breaks down lactic acid into carbon dioxide and water

Muscle Cramps

• Muscle cramps after heavy exercise is from lactic acid building up in muscle cells

Anaerobic Respiration

• Anaerobic respiration breaks down food without oxygen

Oxygen Supply to Cramped Muscles

• Oxygen supply to cramped muscle cells can be increased with hot water baths and massages

Aerobic vs Anaerobic Respiration

• Aerobic respiration produces more energy

Products of Anaerobic Respiration

• The end products of anaerobic respiration in muscle cells are lactic acid and energy

Insufficient Oxygen

• Muscle use anaerobic respiration when the cells lack sufficient oxygen

Assertion/Reason Questions

Question 1

• Assertion (A): Muscle cells in humans respire anaerobically, cramps occur
• Reason (R): Lactic acid accumulation causes muscle cramps
• Both A and R are true, and R is the correct explanation of A

Question 2

• Assertion (A): Yeast, a single-celled organism, can respire anaerobically, producing alcohol as a byproduct
• Reason (R): Yeast lacks the ability to perform cellular respiration
• Both A and R are true, and R is the correct explanation of A

Learn about the role of air and oxygen in respiration and the release of energy. Understand how anaerobes respire without oxygen, and why physical activity leads to increased hunger. Explore anaerobic respiration in humans and relief from muscle cramps.