Respiratory system

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List four features of effective gas exchange surfaces

thin membrane large surface area moist environment rich blood supply

Explain the mechanics of breathing that allow the lungs to fill with

Diaphragm contracts / flattens 2. (External) intercostal muscles contract 3. Ribs/ lungs are pulled upwards and outwards 4. Volume of lungs / size of chest / thoracic cavity increases 5. Pressure within lungs are reduced, and is now lower than the pressure outside the body 6. Air moves in to lungs

Explain the mechanics of breathing that allow the lungs to fill with air

Inhalation (Inspiration):

The diaphragm contracts and moves downward, increasing the volume of the thoracic cavity vertically. Simultaneously, the external intercostal muscles contract, lifting the ribcage and expanding the chest cavity laterally. These actions increase the volume of the thoracic cavity, resulting in a decrease in pressure within the lungs compared to the atmospheric pressure. As a result, air flows into the lungs from the higher pressure outside the body, filling the lungs with oxygen-rich air. Exhalation (Expiration):

The diaphragm relaxes and moves upward, decreasing the volume of the thoracic cavity vertically. The external intercostal muscles relax, allowing the ribcage to lower and the chest cavity to decrease in size laterally. These actions decrease the volume of the thoracic cavity, resulting in an increase in pressure within the lungs compared to the atmospheric pressure. As a result, air flows out of the lungs to the lower pressure outside the body, expelling carbon dioxide-rich air.

(a) Explain the mechanics of breathing that allow the lungs to fill with air

Inhalation (Inspiration): The diaphragm contracts and moves downward, increasing the volume of the thoracic cavity vertically. Simultaneously, the external intercostal muscles contract, lifting the ribcage and expanding the chest cavity laterally. These actions increase the volume of the thoracic cavity, resulting in a decrease in pressure within the lungs compared to the atmospheric pressure. As a result, air flows into the lungs from the higher pressure outside the body, filling the lungs with oxygen-rich air. Exhalation (Expiration): The diaphragm relaxes and moves upward, decreasing the volume of the thoracic cavity vertically. The external intercostal muscles relax, allowing the ribcage to lower and the chest cavity to decrease in size laterally. These actions decrease the volume of the thoracic cavity, resulting in an increase in pressure within the lungs compared to the atmospheric pressure. As a result, air flows out of the lungs to the lower pressure outside the body, expelling carbon dioxide-rich air. Signup and view all the answers

whats the purpose of the C shaped cartilage rings

Maintaining Airway Patency: The cartilage rings provide structural support to the walls of the trachea and bronchi, preventing them from collapsing during inhalation when the air pressure inside the airways decreases. This ensures that the airways remain open and patent, allowing for the unimpeded flow of air into and out of the lungs. Signup and view all the answers

Why does pneumonia result in patient feeling very tired

Pneumonia can make you feel tired because your body is fighting off the infection. Your immune system works overtime to combat the bacteria or virus causing pneumonia, which can leave you feeling drained and fatigued. Additionally, the decreased oxygen levels in your bloodstream due to lung inflammation can contribute to feelings of tiredness. Signup and view all the answers

Why is decreased pressure in the chest cavity the main driver of inhalation

Decreased pressure in the chest cavity is the main driver of inhalation because it creates a pressure gradient that allows air to flow into the lungs. When the diaphragm and external intercostal muscles contract, the volume of the chest cavity increases, causing a decrease in pressure. This lower pressure relative to the atmosphere outside the body draws air into the lungs to equalize the pressure, resulting in inhalation. Signup and view all the answers

1 List the structures that air will travel down, starting from outside of the body.

Nasal cavity Pharynx (throat) Larynx (voice box) Trachea (windpipe) Bronchi (primary, secondary, tertiary) Bronchioles Alveoli (where gas exchange occurs) Signup and view all the answers

2 Describe the structure of the trachea.

The trachea is a rigid, tubular structure composed of C-shaped cartilage rings connected by smooth muscle and fibrous tissue. It has ciliated epithelial lining, which contains mucus-secreting goblet cells and cilia. These structures help trap and remove debris and microorganisms from the airways. Signup and view all the answers

Function of the pleural fluid:

Pleural fluid acts as a lubricant and adhesive, allowing the visceral and parietal pleurae to slide smoothly over each other during breathing movements. It also creates surface tension, which helps maintain the adherence of the lungs to the chest wall, preventing lung collapse. Signup and view all the answers

Difference between a primary bronchus and a tertiary bronchus:

Primary bronchus: Primary bronchi are the largest airway branches that arise directly from the trachea. There are two primary bronchi, one leading to each lung. They further divide into secondary (lobar) bronchi. Tertiary bronchus: Tertiary bronchi are smaller branches that arise from the secondary bronchi within each lobe of the lung. They further divide into smaller bronchioles. Signup and view all the answers

Importance of the convolutions of the mucus membranes in the nasal cavity?

The convolutions (turbinates) increase the surface area of the nasal cavity, facilitating the warming, humidification, and filtration of inhaled air. They also slow down the airflow, allowing more time for air to be warmed, moistened, and cleaned before reaching the lungs. Signup and view all the answers

How the airways in the respiratory system are similar to the branches on a tree and why this is important

The branching pattern of the airways resembles that of a tree, with larger airways branching into smaller ones, similar to the trunk branching into branches and twigs. This branching pattern maximizes surface area for gas exchange and ensures efficient distribution of air to all parts of the lungs. Signup and view all the answers

Comparison and contrast of the structure of the trachea, bronchi, and bronchioles:

Trachea: Contains C-shaped cartilage rings, lined with ciliated pseudostratified columnar epithelium, and has goblet cells. Bronchi: Similar structure to the trachea but with fewer cartilage rings and more smooth muscle. Lined with ciliated pseudostratified columnar epithelium. Bronchioles: Lack cartilage and are primarily composed of smooth muscle. Lined with simple columnar or cuboidal epithelium. Smallest airway branches before reaching the alveoli. Signup and view all the answers

Explain how the movement of air and blood help maintain concentration gradients

The movement of air into the alveoli during inhalation and the movement of blood through the pulmonary capillaries help maintain concentration gradients for efficient gas exchange. During inhalation, fresh air rich in oxygen enters the alveoli, creating a high concentration of oxygen within the alveoli compared to the deoxygenated blood in the pulmonary capillaries. This concentration gradient drives oxygen diffusion from the alveoli into the bloodstream. Conversely, carbon dioxide-rich blood from the body enters the pulmonary capillaries, creating a high concentration of carbon dioxide within the blood compared to the air in the alveoli. This concentration gradient facilitates the diffusion of carbon dioxide from the bloodstream into the alveoli for exhalation. The continuous movement of air and blood ensures that concentration gradients are maintained, allowing for the efficient exchange of oxygen and carbon dioxide between the respiratory system and the bloodstream. Signup and view all the answers

People with cystic fibrosis produce an excessive amount of thick mucus, primarily in the lungs and digestive system. Explain how this would affect the respiratory system, and predict the symptoms exhibited.

The excess, thick and sticky, mucus produced will clog airways, and trap bacteria in it. This leads to further infection, inflammation and respiratory failure. Sufferers will have a persistent cough and be more vulnerable to lung infections of pneumonia and bronchitis. They may be frequently wheezy or experience shortness of breath. Signup and view all the answers

Explain why pneumonia results in the patient feeling very tired.

Pneumonia causes excess mucus and fluid secretion into the alveoli, limiting the amount of air they can hold and also reduces the surface are for gas exchange. Therefore, there is a reduced capacity to oxygenate the blood and remove the carbon dioxide levels in the bloodstream. Less oxygen available will result in the production of less ATP, and as a result, less energy available for the cells. This will lead to an overall feeling of fatigue/tiredness. Signup and view all the answers

Cut off a piece of lung and place it in a beaker of water. Does it float? What does this tell you about the lung?

Pieces of lung do float, indicating that the lung tissue contains a lot of air. Signup and view all the answers

4 Cut open the trachea and observe the interior. Record your observations.

The rings of cartilage can be clearly seen on the inside of the trachea. They are very elastic. Signup and view all the answers

3 List the characteristics of the lungs that make them well suited for gas exchange.

• The alveoli give the lungs a huge internal surface area so that large amounts of gases can be exchanged in a relatively short time. • Each alveolus is well supplied with blood vessels so that as much blood as possible is close to the air in the alveolus. • Continuous flow of blood maintains a gas concentration difference between the air in the alveoli and the blood. • The membrane that forms the wall of the alveolus is very thin, so that gas molecules do not have far to travel to move into or out of the blood. • The lungs are positioned deep inside the body to prevent excessive evaporation of the fluid that covers the respiratory surfaces. It is important that the membrane of the alveolus be covered by a thin layer of moisture, because gases can diffuse into and out of the blood only when they are dissolved in fluid. • Lung volume can be changed by respiratory muscles so that air is moved in and out of the lungs. Signup and view all the answers

5 Explain why it is important that there is cartilage in the trachea and bronchi.

Answer: The cartilage allows the airways to remain open but remain flexible. Signup and view all the answers

6 a Why is a concentration gradient important for the exchange of gases?

Answer: Movement of gases into and out of the blood occurs by diffusion, which can only occur when there is a concentration difference; gases diffuse from a region of higher concentration to one that is lower. Signup and view all the answers

b Why is it that, in the lungs, oxygen diffuses into and carbon dioxide out of the blood, whereas in other body tissues, oxygen diffuses out of and carbon dioxide into the blood?

Answer: Diffusion occurs because of differences in concentration. The concentration of oxygen in the air breathed in is higher than the concentration in the alveolar blood, so it diffuses from the air into the blood. The opposite is true of carbon dioxide. In the tissues, the concentration of oxygen is lower than in the blood, so oxygen diffuses from the blood into the cells. Again, the opposite is true for carbon dioxide, because the cell produces large amounts of carbon dioxide as waste from cellular respiration. Signup and view all the answers

c Explain how a concentration gradient for oxygen and carbon dioxide is maintained between the blood and the air in the alveoli.

• Blood flows constantly through the capillaries. As the blood flowing through the capillaries around each alveolus picks up oxygen and loses carbon dioxide, it is replaced by more blood pumped into the capillaries. This ‘new’ blood is low in oxygen and high in carbon dioxide so that the concentration gradient is maintained. • Air moves in and out of the alveoli as we breathe in and out. The air that has picked up carbon dioxide from, and lost oxygen to, the blood is replaced by ‘new’ air with each breath. The ‘new’ air is low in carbon dioxide and high in oxygen. Signup and view all the answers

8 Explain why asthma is such a serious condition.

Asthma causes difficulty breathing, and a reduced movement of air. Therefore, there is less gas exchange occurring and the blood will carry less oxygen. If this continues for an extended period, the patient may fall unconscious. Signup and view all the answers

9 Compare and contrast bronchi and bronchioles.

Compare: Both are airways transporting air into and out of the lungs. Both have an epithelial lining capable of producing mucus to trap particles/contaminants. Contrast: Bronchi have rings of C-shaped cartilage, smooth muscle and elastin, whereas bronchioles only have smooth muscle and elastin present. Signup and view all the answers

10 To be effective, any surface where materials are taken into the body, or passed out of the body, must have a very large surface area. For the lungs, explain how a large surface area is achieved.

In the lungs a large surface area is achieved by having clusters of alveoli at the end of each bronchiole. The massive quantity of alveoli and the huge surface area they provide – compared with the small volume of air contained – make gas exchange in the lungs very efficient. Signup and view all the answers

11 List five occupations in which people could be at risk of contracting emphysema. What precautions could be taken to reduce the risk of workers contracting the disease?

• timber mill workers • chemical plant workers • miners • outdoor workers in cities that have high atmospheric pollution • hospitality workers where smoking is allowed • people working in smoky environments; for example, fire fighters. reduce risks by: • wearing masks/breathing apparatus • reducing daily exposure • installing extraction fans • prohibiting smoking in areas where non-smokers are likely to be affected. Signup and view all the answers

b What is the reason for the increase in rate and depth of breathing after exercise?

Answer: The increased rate and depth of breathing would have continued after exercise because the girl had incurred an oxygen debt caused by muscles respiring anaerobically. Signup and view all the answers

13 Describe the types of lung damage that smoking can cause.

Answer: Smoke irritates the mucus membranes lining the air passages causing excessive production of mucus. Accumulated mucus cannot be removed and the trapped mucus causes alveoli to rupture, resulting in emphysema. This reduces the surface area available for gas exchange so that breathing becomes difficult. Cancerous growths may develop in the lungs or air passages. Secondary tumours may occur in other parts of the body. Signup and view all the answers

14 If air enters the chest cavity through a puncture wound to the chest wall, the lung may collapse. As the collapsed lung is no longer attached to the chest wall, air cannot be made to move into and out of the lung. However, a person with a collapsed lung can function fairly normally. a Explain how it would be possible for such a person to function in a fairly normal way.

The internal surface area of the lungs greatly exceeds that required for exchange of gases for normal activity. Thus, the surface area of one lung is sufficient. Signup and view all the answers

b Would there be any activities that such a person would not be able to perform?

Answer: A person with only one functioning lung would not be able to engage in strenuous activity because the internal surface of one lung would not be sufficient to supply the increased demand for oxygen or to remove the increased amount of carbon dioxide produced. Signup and view all the answers

15 The ability to voluntarily control breathing is important when speaking, but it is also important when eating or drinking. Explain why this is so.

When swallowing, the epiglottis closes off the trachea so that food and drink cannot enter the lungs and are instead directed down the oesophagus. (See Figure 4.4 on page 88.) Thus, it is important to control breathing while eating or drinking. Signup and view all the answers

16 In expired air resuscitation (mouth-to-mouth resuscitation), air from the rescuer’s lungs is blown into the patient’s lungs. How is expired air able to keep the patient alive?

Expired air still contains 15.8% oxygen. Considering the lungs only take approximately 5% from inspired air, this is an adequate amount to sustain life. Signup and view all the answers

What are the primary causes of emphysema?

Long-term exposure to irritants, especially cigarette smoke Signup and view all the answers

Explain the mechanism by which emphysema leads to chronic obstructive pulmonary disease (COPD).

Damage to the air sacs (alveoli) in the lungs reduces their elasticity, causing air trapping and difficulty exhaling. Signup and view all the answers

What is the primary cause of lung cancer?

Smoking Signup and view all the answers

Describe how lung cancer develops in the body.

Abnormal cells grow uncontrollably in the lungs, forming tumors that can interfere with lung function. Signup and view all the answers

What are the common culprits that cause pneumonia?

Bacterial, viral, or fungal infections Signup and view all the answers

How does pneumonia result in the patient feeling very tired?

The infection causes the body to use more energy to fight it off, leading to fatigue. Signup and view all the answers

What are the symptoms of pneumonia?

Fever, chills, cough, difficulty breathing, chest pain, fatigue, confusion Signup and view all the answers

How does tuberculosis primarily spread?

Through the air when an infected person coughs or sneezes Signup and view all the answers

What are the triggers for asthma?

Allergens, irritants, respiratory infections, exercise, stress Signup and view all the answers

Why is it important for the alveoli to have a huge internal surface area?

To exchange large amounts of gases in a relatively short time Signup and view all the answers

What is the thin membrane that forms the wall of the alveolus important for?

Gas molecules do not have far to travel when moving into or out of the blood Signup and view all the answers

How does asthma affect the airways?

Inflamed, narrow, excess mucus production Signup and view all the answers

What is the effect of untreated tuberculosis?

Life-threatening, extensive lung damage, spread to other organs Signup and view all the answers

Why are the lungs positioned deep inside the body?

To prevent excessive evaporation of the fluid that covers the respiratory surfaces Signup and view all the answers

How does pneumonia cause fatigue in patients?

Inflammation and infection in the air sacs of the lungs lead to fatigue Signup and view all the answers

What is the function of pleural fluid?

To reduce friction and allow the lungs to expand and contract easily Signup and view all the answers

What is the purpose of the nasal convolutions?

that slow down the air, warm and humidify it, help with the sense of smell, and trap pathogens. Signup and view all the answers

What is the function of the cartilage rings in the trachea?

The cartilage rings in the trachea help keep it open for airflow. Signup and view all the answers

What is the function of the rib cage?

The rib cage protects the thoracic organs, including the lungs and heart. Signup and view all the answers

What muscles are involved in respiration?

diaphragm, intercostal muscles Signup and view all the answers

whats the primary muscle for breathing

diaphragm Signup and view all the answers