03-26-07, Respiratory system video notes

The respiratory system provides oxygen to the cells and then provides carbon dioxide a pathway away from the cells. There are mechanics to consider when thinking of respiration. The pulmonary ventilation, external respiration, and two other ventilation processes.

The pulmonary ventilation is where you have (1) expiration and (2) inhalation. The gas exchange between the lungs and the blood is the respiratory exchange. The transfer of gas from the blood to the air is at the lung.

Oxygen attaches to tiny molecules known as hemoglobin molecules which are found in erythrocytes. There are some gases dissolved in the plasma. Much of the carbon dioxide is not in hemoglobin when it is going to the lungs.

The internal respiration process is where there is gas exchange to the cells of the body. So there you have it, four easy parts: respiratory gas transport, internal respiration, and so on.

The brain stem can regulate and control respiration unconsciously. Distractions would otherwise suffocate us. Luckily, the brain stem can manage unconscious breathing. So now we can breath easily to learn about the respiration system.

There are two zones of the respiration system: the conducting zone and the other zone. The conducting zone has the job of transporting, purifying and humidifying incoming air. The conducting zone contains the nose, pharynx, larynx, trachea and bronchial tree.

The nose is made up of an external portion and a nasal cavity. The external portion is the visible portion (tells whether or not you are Jewish, I guess). The nasal cavity is divided into two parts, the medial septal cavity or whatever which divides the nose. The mucous membrane has goblet cells that secret mucous.

Mucus filters, warms, and moistens air that enters the nose.

The pharynx is a fancy name for throat. It is connected superially (upper part) to the cavities of the neck and nose. It connects inferiorly to the larynx. The larynx is a fancy name for the voice box: connected to the pharynx and trachea below. It has nine pieces of cartilage that are connected by membranes and ligaments.

The larynx helps with speech generation. The glottis or larn-genal opening leaves directly to the lungs. The body needs protection to keep food from choking us. One of the cartilages found in the larynx is the epiglottis which closes the opening of the larynx so that we do not choke when eating on meat, dimes or toys.

The larynx is connected to the trachea, or windpipe. There are “c-shaped cartilages”. There's also smooth muscle and connective tissue that construct the wall of the trachea. This allows it to be flexible.

The trachea is covered in cilia, tiny fibers that help move mucous along. The mucous helps to push particles to the mouth or nasal cavity. This is the mucous-ciliary escalator. It pushes and propels, it destroys foreign debris.

The bronchial tree is the last part of the conducting zone. IT begins with the right and left primary bronchi and terminates at the bronchioles. The bronchiol tree is a branching system of tubes. It connects the trachea to the air sacs of the lung. The branches of the bronchiol tree is made up of walls of smooth muscle, which allows the diameter of the tubes to open up or constrict.

Constriction is called bronchiol constriction. Asthma is the form of dyspnea, or in other words, shortness of breath, which make breathing difficult (they are spasms). Bronchioitis is inflammation of the walls of the bronchiole tubes and makes you feel like you are breathing through a wet blanket.

The second part of the respiratory system is the respiratory zone. The respiratory zone is where gas exchange occurs: the lungs and all of its components. It is made up of the bronchioles, the alveoli, the alveolar duct, and the respiratory membranes.

The bronchioles are the tips or the ends of the bronchiole tree. They have little air sacs of alveoli attached to the respiratory bronchioles. The respiratory ducts are also lined with alveoli. The alveolar sacs are further compartments with more gas exchange.

The alveoli are microscopic air sacs that fill the interior of the lungs. They are in direct contact of the pulmonary capillaries of the circulatory system. Capillaries are tiny blood vessels. Actual exchange of blood and gas is where the alveoli are: there's 300 million of them. There's enough of them.

The respiratory membrane is a thin membrane on the outside surfaces of the alveoli. They are fused capillary walls and alveolar. The gases like carbon dioxide and oxygen are exchanged across this membrane. The lungs are the organs that house lots of the organs.

The lungs are paired organs in the plural cavities, which are inside the thoracic cavities. They are made of capillaries, veins, arteries, alveoli, etc. The right lung has three lobes, and the left lung has two lobes. The wimpy lung is the left lung.

Each lung has the pleura or pleural membrane. They help to prevent the spread of infection. The lubrication that they provide makes sure that the lungs do not rub against the rib cage, which would be very painful.

Lung sicknesses and disorders are present, like asthma and emphazema. This occurs when the alveoli rupture and disintegrate. This results in the loss of elasticity of the lungs. Breathing becomes a chore that leads to exhaustion or suffocation.

Pulmonary ventilation is the way to say breathing. There's inhalation and exhalation. The process of pulmonary ventilation is dependent on volume and pressure changes. These relationships are based on Boyle's law: volume is inversely proportional to pressure.

Super Charged World of Chemistry, part 3

Pulmonary ventilation is divided into two processes: inspiration and expiration. Inhaling is where you put air into your lungs. “You put air into my lungs, you're the inspiration” - yeah, bad.

During inspiration, the inspiratory muscles contract inorder to increase interthoracic volume. That's volume of the thoracic cacavity. The volume of the thoracic cavity increases when the muscles contract. As the cavity expands, so do the lungs.

Due to Boyle's law, the pressure inside the lungs decreases, so the pressure inside the lungs is greater inside than outside, so air moves into the lungs from the atmosphere until an equilibrium of pressure and volume is reached.

There is also forced and deep inspiration, usually during vigorous exercise. Forced inspiration is necessary in order to expand your thoracic cavity to let more air into your lungs. These are the pectoralis minor, sternocleidomastoid, and some others. If you don't remember the muscles, go get “the anatomically correct world of anatomy” and see it again.

Expiration is where air is going out of the lungs. It's the opposite of inspiration. You might call it “bizzaro inspiration”, but most people just call it exhaling and breathing out. Expiration is a passive process, which depends on the natural elasticity of the lungs. It takes less work to exhale.

During expiration, the muscles that are used for inspiration are made to relax. The volume in the thoracic cavity decreases. So, the volume in the lungs decreases, and pressure in the lungs increases and runs above the atmospheric pressure and so the air runs into the atmosphere to reach equilibrium again.

Forced expiration is a little bit different. For once, forced expiration is an active process, because certain muscles have to contract in order to do it. Abdominal pressure is increased. There is a decrease in volume in the thoracic cavity. The internal intercostals, the internal and external obliques all help to press air outwards. The pressure in the thoracic cavity is increased.

Forced expiration is used when we need controlled or rhythmic exhalation. So this occurs when you might have to speak or sing or something.

Pulmonary ventilation is effected by lung collapse. This happens when the air enters the pleural cavity, through a severe chest wound. The pressure in the lungs is the same as the pressure in the atmosphere, and so this causes lung collapse.