RESPIRATORY SYSTEM
The respiratory system allows O2 and CO2 to be exchanged between the atmosphere and blood. Cellular respiration is not considered in this section.
Pulmonary Ventilation
The lungs are attached to the inner surface of the chest (thorax) wall via pleural membranes. This means that when the thorax and diaphragm move, the lungs move with them.
Within the lungs, the respiratory surface where gaseous exchange takes place is in the alveoli which have a total surface area of around 100m2, giving a large surface for diffusion. The alveolar wall is a single cell thick and surrounded by a dense bed of capillaries whose walls are also a single cell thick. The alveoli are kept moist to aid diffusion.
Inspiration
• The chest expands under
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Food is actively pushed down the tube by involuntary muscular movements known as peristalis.
• The esophagus terminates at the stomach which is an expandable enlargement of the gastro-intestinal tract. The stomach mixes the food into a liquid called chyme and controls the release of food into the duodenum via the pyloric sphincter.
• The small intestine is around 6½m long and is where the majority of digestion and absorption takes place. The surface area available for absorption is vastly increased by three layers of folding of the surface mucosa. It can considered as three sections: o The duodenum is where most digestion takes places due to the inclusion of secretions from the pancreas (pancreatic juice) and gall bladder (bile). o The jejunum and ileum are where the final stages of digestion and almost all absorption takes place.
• The large intestine is where the last stages of digestion and absorption take place. Bacteria produce some of the B vitamins and vitamin K; water, some ions and vitamins are absorbed and the chyme is turned in faeces.
Physiology of Digestion &
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Two examples below demonstrate how this movement occurs.
As described in the section considering pulmonary respiration, O2 and CO2 move between the blood and air in the lungs from a network of capillaries surrounding the alveoli. The very thin walls of the capillaries and large surface area created by the volume of capillaries surrounding the alveoli ensures that an effective mechanism for gas exchange is available.
Energy from food enters the blood stream either directly via epithelial cells lining the small intestine, or via the lymphatic system. At the tissue end, glucose crosses from capillaries to tissue fluid and then cell membranes by active transport. All cells require energy and this is provided by cellular respiration which turns glucose into adenosine triphosphate (ATP) which is the chemical that cellular processes use to provide energy. The diagram (Cellular Respiration I) shows the inputs and outputs of aerobic respiration within the mitochondria which require constant replenishment of O2 and glucose – plus removal of waste products such as CO2 – by the circulation of
I only chose respiratory as an answer. However, the correct answers are respiratory and cardiovascular because of the pulmonary circulatory system. Gas exchange occurs at pulmonary capillary beds.
Healthy lung tissue is predominately soft, elastic connective tissue, designed to slide easily over the thorax with each breath. The lungs are covered with visceral pleura which glide fluidly over the parietal pleura of the thoracic cavity thanks to the serous secretion of pleural fluid (Marieb, 2006, p. 430). During inhalation, the lungs expand with air, similar to filling a balloon. The pliable latex of the balloon allows it to expand, just as the pliability of lungs and their components allows for expansion. During exhalation, the volume of air decrease causing a deflation, similar to letting air out of the balloon. However, unlike a balloon, the paired lungs are not filled with empty spaces; the bronchi enter the lungs and subdivide progressively smaller into bronchioles, a network of conducting passageways leading to the alveoli (Marieb, 2006, p. 433). Alveoli are small air sacs in the respiratory zone. The respiratory zone also consists of bronchioles and alveolar ducts, and is responsible for the exchange of oxygen and carbon dioxide (Marieb, 2006, p. 433).
Esophagus: Esophagus is a long straight tube which connects the pharynx to the stomach. Once the food has been reduced to a soft mush, the tongue pushes it to the throat which leads to a long straight tube called esophagus. The esophagus squeezes the mass of food with rhythmic muscle contraction called peristalsis which then forces the food to the stomach.
In order for this breakdown to happen, the ‘tube’ through which the food travels requires assistance from a number of other digestive organs starting with the salivary glands, and later receiving
This is a J-shaped organ, that can contract or expand, depending on what’s inside, due to the nature of its elasticity. It has two valves, one at the opening called the cardiac sphincter, which prevent a back flow of food into oesophagus, and the other one at the exit called the pyloric sphincter (situated at the entrance of the duodenum), which regulates food leaving the stomach. (Tucker.
It is when much needed oxygen is obtained by the body in order for respiration to take place and the waste CO2 is taken out of the body. In us mammals, the exchange takes place in the lungs which contain a large number of alveoli. These are sponge-like structures in which the diffusion takes place. They are highly adapted to diffuse the gases as they give a large surface area for exchange of the gases.
They are oxygen and carbon dioxide, and they are transported throughout the body in the blood. Plasma has the capability to transport some of the dissolved oxygen and carbon dioxide, but the majority of the gases that are transported in the blood are bound to transport molecules. However, when the partial pressure of carbon dioxide is higher in the tissues, the enzymes catalyzes a reaction between the carbon dioxide and the water to form carbonic acid. Carbonic acid will then dissociate into hydrogen ion and bicarbonate ion. When the partial pressure of carbon dioxide is low in the lungs, the reactions reverse and carbon dioxide is freed into the lungs to be
Mouth- Digestion begins in the mouth. Physical actions, such as chewing, breaks food into small parts so it can be easily digested. Next, salivary glands secrete an enzyme called saliva to mix with food to start the breaking down of carbohydrates (WebMD (2).) From the mouth, food travels to the pharynx, or throat, by swallowing,
...ve eaten, to break down the food into a liquid mixture and to slowly empty that liquid mixture into the small intestine. Once the bolus has entered your stomach it begins to be broken down with the help of the strong muscles and gastric juices which are located in the walls of your stomach. The gastric juices are made up of hydrochloric acid, water, and mucus- and the main enzyme inside of your stomach is what is known as pepsin, which needs to be surrounded in an acidic setting in order to do its job, that is to break down protein. Once the bolus has been inside of your stomach for long enough it begins to form into a liquid called chyme, and what keeps the chyme from flowing back into our esophagus are ring shaped muscles known as sphincters located at the beginnings and ends of the stomach and they have the task of controlling the flow of solids and liquids.
The larynx provides a passageway for air between the pharynx and the trachea. The trachea is made up of mainly cartilage which helps to keep the trachea permanently open. The trachea passes down into the thorax and connects the larynx with the bronchi, which passes to the lungs. 3. Describe the mechanisms of external respiration including the interchange of gases within the lungs.
The circulatory system and respiratory system share a highly important relationship that is crucial to maintaining the life of an organism. In order for bodily processes to be performed, energy to be created, and homeostasis to be maintained, the exchange of oxygen from the external environment to the intracellular environment is performed by the relationship of these two systems. Starting at the heart, deoxygenated/carbon-dioxide (CO2)-rich blood is moved in through the superior and inferior vena cava into the right atrium, then into the right ventricle when the heart is relaxed. As the heart contracts, the deoxygenated blood is pumped through the pulmonary arteries to capillaries in the lungs. As the organism breathes and intakes oxygenated air, oxygen is exchanged with CO2 in the blood at the capillaries. As the organism breathes out, it expels the CO2 into the external environment. For the blood in the capillaries, it is then moved into pulmonary veins and make
When you breathe in, air containing carbon dioxide (CO2) and oxygen (O2) it moves down your trachea; a tunnel containing cartilage and smooth tissue. Air then travels through two hollow tubes called bronchi; narrow branches lined with smooth muscle, mucosal and ringed cartilage to support the structure. The bronchi divide out into smaller tunnels called bronchioles; are small branches 0.5-1mm, lined with muscular walls to help dilate and constrict the airway. At the end of the bronchioles are little air sacs called alveoli; which assist in gas exchange of O2 and CO2. (Eldridge, 2016) Towards the end of alveoli are small blood vessel capillaries. O2 is moved through the blood stream through theses small blood vessels (capillaries) at the end of the alveoli and the CO2 is then exhaled. (RolandMedically,
Food comes in the mouth, and chewing and saliva start to break it up and make it smaller to swallow. Then, the food goes down through the esophagus to the stomach. Moving of the stomach’s muscular wall keeps going to break down the food. The grinded up food eventually passes
The human digestion system is very complex. It starts with the mouth, salivary glands, pharynx, esophagus, stomach, liver, pancreas, gallbladder, small intestine, large intestine, then ends/exits with the anus. Each step is essential to the whole system. For example, the mouth chews food and mixes it with saliva produced by the salivary glands, and then the pharynx swallows chewed food mixed with saliva, this is followed by the food traveling through the esophagus to the stomach where the food gets a bath and mixes with acids and enzymes. After the stomach, the liver, pancreas, and gallbladder produce, stores, and releases bile and bicarbonates. Bile is produced in the liver and aids in digestion and absorption of fat while the gallbladder stores bile and releases it into the small intestine when needed. Following the process into the small intestine, this is where nutrients will be absorbed into the blood or lymph (most digestion occurs here). Next is the large intestine this is where water and some vitamins and minerals are absorbed. Finally, it is the end of the road, the anus. At...
The roles of the circulatory and respiratory system both carry important responsibilities and are essential in their jobs to the human body. The circulatory system is one, if not the, most important system in the human body. The circulatory system is made up of the heart, blood, and blood vessels. Within the blood vessels, there are three types: arteries, veins, and capillaries. The heart is an organ made up of cardiac muscle that has a role similar to a pump. When the muscles in the heart contract, it pumps fresh blood away from the heart, through a main artery called the aorta, and to the organs and cells of the body. Nutrients and oxygen then enter the cells through diffusion of the tissues. The respiratory system transports oxygen to the circulatory system. When transporting oxygen to the circulatory system, this will in turn transport oxygen to the rest of the cells in the body. Aside from transporting oxygen to the body, the respiratory system also plays a role in the removal of carbon dioxide and other contaminants in the body. These two systems effectively and efficiently work together in order to supply the body with oxygen and remove carbon dioxide and any other