Gas exchange

Why do you breathe?

We breathe because we need oxygen. Breathing also releases carbon dioxide from our bodies into the air. The respiratory system is the body system that brings air containing oxygen into the body and releases carbon dioxide into the atmosphere.

How We Breathe?
Most of the time, you breathe without thinking about it. Breathing is mostly an involuntary action that is controlled by a part of your brain that also controls your heart beat. If you swim, do yoga, or sing, you know you can control your breathing, however. Taking air into the body through the nose and mouth is called inhalation. Pushing air out of the body through the nose or mouth is called exhalation. 

How do lungs allow air in? As mentioned above, air moves into and out of the lungs by the movement of muscles. The most important muscle in the process of breathing is the diaphragm, a sheet of muscle that spreads across the bottom of the rib cage. The diaphragm and rib muscles contract and relax to move air into and out of the lungs. During inhalation, the diaphragm contracts and moves downward. The rib muscles contract and cause the ribs to move outward. This causes the chest volume to increase. Because the chest volume is larger, the air pressure inside the lungs is lower than the air pressure outside. This difference in air pressures causes air to be sucked into the lungs. When the diaphragm and rib muscles relax, air is pushed out of the lungs. Exhalation is similar to letting the air out of a balloon.

How does the inhaled oxygen get into the bloodstream? 

The exchange of gasses between the lungs and the blood happens in tiny sacs called alveoli. The walls of the alveoli are very thin and allow gases to pass though them. The alveoli are lined with capillaries. Oxygen moves from the alveoli to the blood in the capillaries that surround the alveoli. At the same time, carbon dioxide moves in the opposite direction, from capillary blood to the alveoli.

BREATHING AND RESPIRATION
The process of getting oxygen into the body and releasing carbon dioxide is called respiration. Sometimes breathing is called respiration, but there is much more to respiration than just breathing. Breathing is only the movement of oxygen into the body and carbon dioxide out of the body. The process of respiration also includes the exchange of oxygen and carbon dioxide between the blood and the cells of the body.

Summary
  • The diaphragm and rib muscles contract when you inhale and relax when you exhale.
  • The process of getting oxygen into the body and releasing carbon dioxide is called respiration.
source

VENTILATION

Respiration begins with ventilation. This is the process of moving air in and out of the lungs. The lungs are the organs in which gas exchange takes place between blood and air.

  • Air enters the respiratory system through the nose. As the air passes through the nasal cavity, mucus and hairs trap any particles in the air. The air is also warmed and moistened so it won’t harm delicate tissues of the lungs.
  • Next, the air passes through the pharynx, a long tube that is shared with the digestive system. A flap of connective tissue called the epiglottis closes when food is swallowed to prevent choking.
  • From the pharynx, air next passes through the larynx, or voice box. The larynx contains vocal cords, which allow us to produce vocal sounds.
  • After the larynx, air moves into the trachea, or wind pipe. This is a long tube that leads down to the chest.
  • In the chest, the trachea divides as it enters the lungs to form the right and left bronchi. The bronchi contain cartilage, which prevents them from collapsing. Mucus in the bronchi traps any remaining particles in air. Tiny, hair-like structures called cilia line the bronchi and sweep the particles and mucus toward the throat so they can be expelled from the body.
  • Finally, air passes from the bronchi into smaller passages called bronchioles. The bronchioles end in tiny air sacs called alveoli.

Respiration

Files:

Respiratory Notes Filled in
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practice files will be updated shortly 

Helpful links

Helpful site (thanks jordyn)

breathing 

Vocabulary

Breathing Vocabulary
  • alveoli: Tiny sacs in the lungs where gas exchange takes place.
  • diaphragm : A sheet of muscle that spreads across the bottom of the rib cage.
  • exhalation: Pushing air out of the body through the nose or mouth.
  • inhalation: Taking air into the body through the nose and mouth.
  • respiration: The process of getting oxygen into the body and releasing carbon dioxide.
  • bronchi: Air passages in the respiratory tract that conduct air into the lungs.
  • larynx: Respiratory organ between the pharynx and trachea; also called the voice box because it allows the production of vocal sounds.
  • pharynx: Long, tubular organ that connects the mouth and nasal cavity with the larynx; food and air pass through it.
  • trachea: Long, tubular organ, also called the wind pipe, that carries air between the larynx and lungs.