Respiratory System: Inhaling and Exhaling Mechanism

Questions and Answers

What is the total number of ribs in the human body?

What is the function of the intercostal muscles?

To contract and move the ribs outwards

What is the name of the bone in the middle of the chest?

Breastbone

How many pairs of ribs attach directly to the sternum?

7 Signup and view all the answers

What controls the contraction of the intercostal muscles?

The brain Signup and view all the answers

What is the term for 'between' in the context of the intercostal muscles?

Inter Signup and view all the answers

What happens to the ribs when the intercostal muscles contract?

They move outwards Signup and view all the answers

What is the shape of the muscle that rides down the bottom of the ribcage?

Upside-down U shape Signup and view all the answers

What happens to the alveoli when the protein molecules snap back into their original size?

They decrease in size Signup and view all the answers

What type of energy is required for inhaling?

Chemical energy Signup and view all the answers

What drives the process of exhaling?

Elastic recoil Signup and view all the answers

What is the result of the protein molecules snapping back into their original size?

A decrease in lung volume Signup and view all the answers

What is the energy source used during exhaling?

Elastic potential energy Signup and view all the answers

What is the difference between inhaling and exhaling in terms of energy usage?

Inhaling uses chemical energy, while exhaling uses elastic potential energy Signup and view all the answers

What is the shape of the diaphragm muscle when it is relaxed?

Dome-like Signup and view all the answers

What happens to the heart and lungs when the diaphragm muscle contracts?

They move downwards and outwards Signup and view all the answers

What is the function of elastin protein in the alveoli?

To provide elasticity to the alveoli Signup and view all the answers

What happens to the volume of the lungs when the diaphragm muscle contracts and the intercostal muscles move out?

It increases Signup and view all the answers

What is the approximate number of alveoli in the human lungs?

500 million Signup and view all the answers

What happens to the elastin molecules when the muscles relax?

They recoil Signup and view all the answers

What is the driving force for why the volume goes back down during exhalation?

The recoil of the elastin molecules Signup and view all the answers

What happens to the alveoli when the diaphragm muscle contracts and the intercostal muscles move out?

They increase in size Signup and view all the answers

What is the result of the diaphragm muscle contracting and the intercostal muscles moving out?

Inhalation Signup and view all the answers

What is the purpose of the diaphragm muscle contracting?

To increase the volume of the lungs Signup and view all the answers

Study Notes

Breathing Process

The breastbone, also known as the sternum, is a bone in the middle of the chest where the ribs attach.
There are 24 ribs in total, with 14 ribs attaching directly to the sternum.
Between the ribs, there are intercostal muscles that are controlled by the brain and play a crucial role in the breathing process.

Inhaling

When the brain signals to take a deep breath, the intercostal muscles contract, causing the ribs to move outwards.
The diaphragm muscle, which is dome-shaped, contracts and flattens, moving downwards and increasing the volume of the thoracic cavity.
As the diaphragm moves down, the lungs and heart are physically moved downwards and outwards, expanding the lung volume.
The expansion of the lungs is due to the stretching of alveoli, which increases their size.
There are approximately 500 million alveoli, each surrounded by protein called elastin, which acts like a rubber band.

Exhaling

When the muscles relax, the elastin proteins snap back, causing the alveoli to recoil and decrease in size, reducing the lung volume.
The recoil of the elastin proteins is the driving force behind the decrease in volume during exhalation.
Exhaling does not require chemical energy, unlike inhaling, which uses ATP (adenosine triphosphate) for muscle contraction.
The process of inhaling and exhaling is distinct, with inhaling requiring energy and exhalation driven by elastic potential energy.