When the heart muscle relaxes, the blood is released from the atrium and into the right ventricle. The right ventricle then pushes the blood through the pulmonary valve and into the pulmonary artery, where the blood is delivered to the lungs for retrieval of oxygen.
The blood is then returned to the left side of the heart. As on the right side, the left atrium receives the blood and sends it to the ventricle when the heart muscle relaxes. Finally, the blood is pushed to the aorta and delivered to the rest of the body. The lungs are where carbon dioxide and oxygen are exchanged. Lungs are the primary organ in the respiratory system. The process is called gas exchange. When you inhale, the alveoli in the lungs fill with oxygen.
The oxygen is sent to blood cells in the capillaries that surround the alveoli. When you exhale, the carbon dioxide in the blood is sent to the alveoli, where it is expelled from the body. At this point, the blood is now filled with oxygen and returns to the heart.
The heart's left ventricle is where the cardiovascular and respiratory systems come together, as this is where the oxygenated blood is delivered from the lungs into the blood.
The left ventricle of the heart opens, and blood is pumped into the chamber to prepare for delivery to the body's tissues. The valve to the aorta opens, and the blood is pumped into the artery.
The aorta is the major artery of the body that delivers large amounts of blood to the different parts of the body, including the legs, the arms and the brain. Did you know that you're able to produce sounds because of the air you breathe?
It's true! In the laryngeal skeleton a structure comprised of cartilage in the throat area are the true vocal folds, or vocal cords, which allow you to speak. When air passes over the folds, they vibrate, and it is these vibrations that others and yourself!
While people have similar body structures, no two people are completely alike, which also is true for distinct voices. Ever wonder how you're able to smell something yummy and recognize it? The respiratory and nervous systems work together to identify odors in your environment. The cribiform plate of the ethmoid bone supports the olfactory bulb and the foramina in the ethmoid give passage to branches of the olfactory nerves.
I know I've mentioned the role that blood plays in your body at some point. To recap, blood is the fuel that keeps you going! Oxygenated blood is brought to organs and tissues via the arteries, while veins bring deoxygenated blood back to the heart to be replenished. The point is, without the respiratory system your blood would be useless. The circulatory and respiratory systems work together to circulate blood and oxygen throughout the body.
Air moves in and out of the lungs through the trachea, bronchi, and bronchioles. Blood moves in and out of the lungs through the pulmonary arteries and veins that connect to the heart.
The pulmonary vessels operate backwards from the rest of the body's vasculature: The pulmonary arteries carry deoxygenated blood from the heart to the lungs, and the pulmonary veins carry oxygenated blood back to the heart to be distributed to the body.
The muscular and nervous systems enable the involuntary breathing mechanism. The main muscles in inhalation and exhalation are the diaphragm and the intercostals shown in blue , as well as other muscles.
Exhalation is a passive action, as the lungs recoil and shrink when the muscles relax. Insect respiration is independent of its circulatory system; therefore, the blood does not play a direct role in oxygen transport. Insects have a highly specialized type of respiratory system called the tracheal system, which consists of a network of small tubes that carries oxygen to the entire body. The tracheal system is the most direct and efficient respiratory system in active animals.
The tubes in the tracheal system are made of a polymeric material called chitin. Insect bodies have openings, called spiracles, along the thorax and abdomen. These openings connect to the tubular network, allowing oxygen to pass into the body Figure Air enters and leaves the tracheal system through the spiracles. Some insects can ventilate the tracheal system with body movements.
In mammals, pulmonary ventilation occurs via inhalation breathing. During inhalation, air enters the body through the nasal cavity located just inside the nose Figure As air passes through the nasal cavity, the air is warmed to body temperature and humidified.
The respiratory tract is coated with mucus to seal the tissues from direct contact with air. Mucus is high in water. As air crosses these surfaces of the mucous membranes, it picks up water. Particulate matter that is floating in the air is removed in the nasal passages via mucus and cilia. The processes of warming, humidifying, and removing particles are important protective mechanisms that prevent damage to the trachea and lungs.
Thus, inhalation serves several purposes in addition to bringing oxygen into the respiratory system. Which of the following statements about the mammalian respiratory system is false? From the nasal cavity, air passes through the pharynx throat and the larynx voice box , as it makes its way to the trachea Figure The human trachea is a cylinder about 10 to 12 cm long and 2 cm in diameter that sits in front of the esophagus and extends from the larynx into the chest cavity where it divides into the two primary bronchi at the midthorax.
It is made of incomplete rings of hyaline cartilage and smooth muscle Figure The trachea is lined with mucus-producing goblet cells and ciliated epithelia. The cilia propel foreign particles trapped in the mucus toward the pharynx. The forced exhalation helps expel mucus when we cough.
The end of the trachea bifurcates divides to the right and left lungs. The lungs are not identical. The right lung is larger and contains three lobes, whereas the smaller left lung contains two lobes Figure The muscular diaphragm, which facilitates breathing, is inferior below to the lungs and marks the end of the thoracic cavity.
In the lungs, air is diverted into smaller and smaller passages, or bronchi. Air enters the lungs through the two primary main bronchi singular: bronchus. Each bronchus divides into secondary bronchi, then into tertiary bronchi, which in turn divide, creating smaller and smaller diameter bronchioles as they split and spread through the lung.
Like the trachea, the bronchi are made of cartilage and smooth muscle. At the bronchioles, the cartilage is replaced with elastic fibers. In humans, bronchioles with a diameter smaller than 0.
They lack cartilage and therefore rely on inhaled air to support their shape. As the passageways decrease in diameter, the relative amount of smooth muscle increases. The terminal bronchioles subdivide into microscopic branches called respiratory bronchioles.
The respiratory bronchioles subdivide into several alveolar ducts. Numerous alveoli and alveolar sacs surround the alveolar ducts. The alveolar sacs resemble bunches of grapes tethered to the end of the bronchioles Figure In the acinar region, the alveolar ducts are attached to the end of each bronchiole.
At the end of each duct are approximately alveolar sacs, each containing 20 to 30 alveoli that are to microns in diameter. Gas exchange occurs only in alveoli. Alveoli are made of thin-walled parenchymal cells, typically one-cell thick, that look like tiny bubbles within the sacs. Alveoli are in direct contact with capillaries one-cell thick of the circulatory system.
Such intimate contact ensures that oxygen will diffuse from alveoli into the blood and be distributed to the cells of the body. In addition, the carbon dioxide that was produced by cells as a waste product will diffuse from the blood into alveoli to be exhaled.
This organization produces a very large surface area that is available for gas exchange. The surface area of alveoli in the lungs is approximately 75 m 2. This large surface area, combined with the thin-walled nature of the alveolar parenchymal cells, allows gases to easily diffuse across the cells.
Watch the following video to review the respiratory system. The air that organisms breathe contains particulate matter such as dust, dirt, viral particles, and bacteria that can damage the lungs or trigger allergic immune responses. The respiratory system contains several protective mechanisms to avoid problems or tissue damage. In the nasal cavity, hairs and mucus trap small particles, viruses, bacteria, dust, and dirt to prevent their entry.
If particulates do make it beyond the nose, or enter through the mouth, the bronchi and bronchioles of the lungs also contain several protective devices. The lungs produce mucus —a sticky substance made of mucin , a complex glycoprotein, as well as salts and water—that traps particulates. The bronchi and bronchioles contain cilia, small hair-like projections that line the walls of the bronchi and bronchioles Figure These cilia beat in unison and move mucus and particles out of the bronchi and bronchioles back up to the throat where it is swallowed and eliminated via the esophagus.
In humans, for example, tar and other substances in cigarette smoke destroy or paralyze the cilia, making the removal of particles more difficult. In addition, smoking causes the lungs to produce more mucus, which the damaged cilia are not able to move.
This causes a persistent cough, as the lungs try to rid themselves of particulate matter, and makes smokers more susceptible to respiratory ailments. Animal respiratory systems are designed to facilitate gas exchange. In mammals, air is warmed and humidified in the nasal cavity. Air then travels down the pharynx, through the trachea, and into the lungs.
In the lungs, air passes through the branching bronchi, reaching the respiratory bronchioles, which house the first site of gas exchange. The respiratory bronchioles open into the alveolar ducts, alveolar sacs, and alveoli. Because there are so many alveoli and alveolar sacs in the lung, the surface area for gas exchange is very large. Several protective mechanisms are in place to prevent damage or infection. These include the hair and mucus in the nasal cavity that trap dust, dirt, and other particulate matter before they can enter the system.
In the lungs, particles are trapped in a mucus layer and transported via cilia up to the esophageal opening at the top of the trachea to be swallowed. The circulatory system is a network of vessels—the arteries, veins, and capillaries—and a pump, the heart.
Blood circulates inside blood vessels and circulates unidirectionally from the heart around one of two circulatory routes, then returns to the heart again; this is a closed circulatory system. Open circulatory systems are found in invertebrate animals in which the circulatory fluid bathes the internal organs directly even though it may be moved about with a pumping heart. The heart is asymmetrical, with the left side being larger than the right side, correlating with the different sizes of the pulmonary and systemic circuits Figure In humans, the heart is about the size of a clenched fist; it is divided into four chambers: two atria and two ventricles.
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