pediagenosis: Respiratory
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Showing posts with label Respiratory. Show all posts
Showing posts with label Respiratory. Show all posts

Monday, November 11, 2019

Topography Of The Lungs (Posterior View)

Topography Of The Lungs (Posterior View)


Topography Of The Lungs (Posterior View)
The apex of the lung extends as far superiorly as the vertebral end of the first rib and therefore as high as the first thoracic vertebra. From there, the lung extends inferiorly as far as the diaphragm, with the base of the lung resting on the diaphragm and fitted to its superior surface. Because of the diaphragm’s domed shape, the level of the highest point on the base of the right lung is about at the eighth to ninth thoracic vertebrae. The highest point on the base of the left lung is a fraction of an inch lower. From these high points, the bases of the two lungs follow the curves of the diaphragm to reach the levels described earlier for the inferior borders of the lungs.
MEDIASTINUM

MEDIASTINUM


MEDIASTINUM
The mediastinum is that portion of the thorax that lies between the right and left pleural sacs and is bounded ventrally by the sternum and dorsally by the bodies of the thoracic vertebrae. The superior boundary of the mediastinum is defined by the thoracic inlet, and its inferior boundary is formed by the diaphragm. By convention, the mediastinum is divided into superior and inferior parts by a plane extending horizontally from the base of the fourth vertebral body to the angle of the sternum. The superior mediastinum contains the aortic arch; the brachiocephalic (innominate) artery; the beginnings of the left common carotid and left subclavian arteries; the right pulmonary artery trunk; the right and left brachiocephalic (innominate) veins as they come together to form the superior vena cava; the trachea with right and left vagus, cardiac, phrenic, and left recurrent laryngeal nerves; the esophagus and the thoracic duct; most of the thymus; the superficial part of the cardiac plexus; and a few lymph nodes.
BRONCHIAL ARTERIES

BRONCHIAL ARTERIES


BRONCHIAL ARTERIES
The lungs receive blood from two sets of arteries. The pulmonary arteries follow the bronchi and ramify into capillary networks that surround the alveoli, allowing exchange of oxygen and carbon dioxide. The bronchial arteries derive from the aorta. They supply oxygenated blood to the tissues of the lung that are not in close proximity to inspired air, such as the muscular walls of the larger pulmonary vessels and airways (to the level of the respiratory bronchioles) and the visceral pleurae. The origin of the right bronchial artery is quite variable. It arises frequently from the third right posterior intercostal artery (the first right aortic intercostal artery) and descends to reach the posterior aspects of the right main bronchus. It may arise from a common stem with the left inferior bronchial artery, which origi- nates from the descending aorta slightly inferior to the point where the left main bronchus crosses it. Or it may arise from the inferior aspect of the arch of the aorta and course behind the trachea to reach the posterior wall of the right main bronchus.
RELATIONSHIPS OF THE TRACHEA AND MAIN BRONCHI

RELATIONSHIPS OF THE TRACHEA AND MAIN BRONCHI


RELATIONSHIPS OF THE TRACHEA AND MAIN BRONCHI
The trachea begins at the lower border of the larynx (just below the cricoid cartilage) at about the level of the sixth cervical vertebra and ends at about the level of the upper border of the fifth thoracic vertebra, where it divides into the two main bronchi. The thyroid gland lies on the anterior and both lateral aspects of the highest part of the trachea.
Medial Surface Of The Lungs

Medial Surface Of The Lungs


Medial Surface Of The Lungs
The medial (mediastinal) surfaces of the right and left lungs present concave mirror images of the right and left sides of the mediastinum so that in addition to the structures forming the root of the lung, the medial lung surface presents distinct impressions made by the structures constituting the mediastinum (see Plates 1-18 and 1-19).
Bronchopulmonary Segments

Bronchopulmonary Segments


Bronchopulmonary Segments
A bronchopulmonary segment is that portion of the lung supplied by the primary branch of a lobar bronchus. Each segment is surrounded by connective tissue that is continuous with visceral pleura and forms a separate, functionally independent respiratory unit. The artery supplying a segment follows the segmental bronchus but the segmental veins are at the periphery of the segment and thus can be helpful in delineating it.

Wednesday, October 9, 2019

Diaphragm (Viewed From Above)

Diaphragm (Viewed From Above)


Diaphragm (Viewed From Above)
The diaphragm is a curved musculotendinous septum separating the thoracic from the abdominal cavity, forming the floor of the thoracic cavity with its convex upper surface facing the thorax. The dome of the diaphragm on the right side is as high as the fifth costal cartilage (varying with the phase of respiration) and on the left is only slightly lower, so that some of the abdominal viscera are covered by the thoracic cage.
Intercostal Nerves And Arteries

Intercostal Nerves And Arteries


Intercostal Nerves And Arteries
The typical thoracic spinal nerve is formed by the junction of a dorsal root and a ventral root near the intervertebral foramen below the vertebra having the same number as the nerve. The dorsal root is made up of a series of rootlets that emerge from one segment of the spinal cord between its dorsal and lateral white columns; it contains the nerve cell bodies of the afferent neurons that enter the spinal cord through it. This collection of nerve cell bodies causes a swelling of the root, named the dorsal root ganglion. A series of rootlets composed of axons of ventral-born gray cells leaves the same segment of the cord between the lateral and ventral white columns to form the ventral root of the spinal nerve.
Sleep Apnoea

Sleep Apnoea


Sleep Apnoea
Sleep apnoea (or sleep-disordered breathing) is common, with a vast potential for improvement in quality of life. It is caused by obstruction of the upper airways (obstructive sleep apnoea), and more rarely central sleep apnoea (CSA), where the central control of ventilation is disturbed. It can lead to significan sleep deprivation and fragmentation and thus daytime hypersomnolence (sleepiness), with consequent decreased quality of life, mental and physical performance, and increased risk of accidents and cardiovascular disease, such as hypertension. Sleep-disordered breathing is diagnosed using polysomnography (Fig. 44a), which records the electroencephalography (EEG) for sleep patterns, movements of abdomen and thorax to assess breathing, oronasal f ow and oximetry for O2 saturation. Normal sleep (Fig. 44a) consists of rapid eye movement (REM,  ̴25%) and non-rapid eye movement (NREM) sleep. REM sleep is characterized by an awakepattern EEG, voluntary muscle atonia and dreaming. Ventilatory drive is normally diminished in REM sleep, causing a slight fall in Pao2 and a rise in Paco2. Sleep apnoea is associated with multiple periods of hypoxaemia and partial awakenings (Fig. 44b and c).
Oxygenation And Oxygen Therapy

Oxygenation And Oxygen Therapy


Oxygenation And Oxygen Therapy
Suff cient O2 must be delivered to the tissues to support metabolism, and the tissues must be able to utilize it. Tissue hypoxia can be caused by low arterial Po2 and therefore blood O2 content (hypoxaemia); inadequate tissue blood flow (ischaemia, cardiac failure, emboli); low haemoglobin concentration (anaemia); abnormal oxygen dissociation curve (haemoglobinopathies, CO poisoning); and poisoning of intracellular oxygen usage (e.g. cyanide and sepsis). Tissue hypoxia occurs within 4 minutes of failure of any of these systems because tissue and lung O2 reserves are small. Clinical features are often non-specific including altered mental state, dyspnoea, hyperventilation, arrhythmias and hypotension (see Chapter 23). Anaemia and abnormal dissociation curves are discussed in Chapter 8.

Monday, August 26, 2019

Acute Respiratory Distress Syndrome

Acute Respiratory Distress Syndrome


Acute Respiratory Distress Syndrome
Acute respiratory distress syndrome (ARDS) is most simply define as 'leaky lung syndrome' or 'low-pressure (i.e. non-cardiogenic) pulmonary oedema'. It describes an acute, diffuse inflammator lung injury, often in previously healthy lungs (Fig. 41a) in response to a variety of direct (i.e. inhaled) or indirect (i.e. bloodborne) insults.

Sunday, August 4, 2019

Lung Cancer

Lung Cancer


Lung Cancer
More people die in the USA and Europe from lung cancer than from breast, prostate and colon cancer combined. Furthermore, the number of cases is likely to increase in the next 25 years due to continued use of cigarettes, particularly in women. Lung cancer has a worse prognosis than other common cancers, with an overall 5-year survival of 13%.
The Immunocompromised Host

The Immunocompromised Host


The Immunocompromised Host
The immune system is most frequently impaired after chemotherapy and in patients with human immunodeficien y virus (HIV) infection. Immunodeficien y also occurs in patients with malignancies of the lym- phoproliferative system (e.g. leukaemia), immediately following bone marrow transplants (BMT) and in those on immunosuppressive drugs (e.g. steroids and azothioprine) particularly after transplant surgery (e.g. renal). Malnutrition or chronic illness (e.g. diabetes) may also impair immunity. Respiratory disease is particularly common in the immunocompromised host.
Pulmonary Tuberculosis

Pulmonary Tuberculosis


Pulmonary Tuberculosis
Worldwide, tuberculosis (TB) affects 10 million people and causes 2 million deaths each year. In developed countries it is uncommon, affecting approximately 1 per 10 000 population. Pulmonary TB is most common in Asian, Chinese and West Indian people. Airborne transmission and close contact spread the disease. Those who are elderly, malnourished or immunosuppressed (HIV infection, diabetes mellitus, corticosteroid therapy, alcoholism, intercurrent lymphoma) are more susceptible. Improved housing and nutrition reduce incidence.

Saturday, June 29, 2019

Hospital-Acquired (Nosocomial) Pneumonia

Hospital-Acquired (Nosocomial) Pneumonia


Hospital-Acquired (Nosocomial) Pneumonia
Hospital-acquired (nosocomial) pneumonia (HAP) including ventilator-associated pneumonia (VAP) and healthcare-associated pneumonia (HCAP) affects 0.5-2% of hospital patients and is a leading cause of nosocomial infection (i.e. with wound, urinary tract and bloodstream). Pathogenesis, causative organisms and outcome differ from community-acquired pneumonia (CAP). Preventative measures and early antibiotic therapy, guided by awareness of the role of multidrug-resistant (MDR) pathogens, improve outcome.
Community Acquired Pneumonia

Community Acquired Pneumonia


Community-Acquired Pneumonia
Pneumonia is an acute lower respiratory tract (LRT) illness, usually due to infection, associated with fever, focal chest symptoms ( ± signs) and new shadowing on chest X-ray (CXR) (Fig. 36a). Table 1 lists microorganisms and pathological insults that cause pneumonia.

Monday, June 3, 2019

Pneumothorax

Pneumothorax


Pneumothorax
A pneumothorax is a collection of air between the visceral and parietal pleura causing a real rather than potential pleural space. Recognition and early drainage can be lifesaving. Predisposing and precipitating factors include necrotizing lung pathology, chest trauma, ventilator-associated lung injury and cardiothoracic surgery.
Cystic Fibrosis And Bronchiectasis

Cystic Fibrosis And Bronchiectasis


Cystic Fibrosis And Bronchiectasis
Cystic fibrosis (CF) is the primary cause of severe chronic lung disease in children, although 90% of children now survive into their second decade (Fig. 34a). CF is characterized by chronic bronchopulmonary infection and airway obstruction (Fig. 34b) and by exocrine pancreatic insufficiency with consequent effects on gut function, nutrition and development. The key feature of CF is increased viscosity and subsequent stasis of epithelial mucus. There is usually an increased salt content of sweat. Figure 34c shows some associated disorders.
Occupational And Environmental-Related Lung Disease

Occupational And Environmental-Related Lung Disease


Occupational And Environmental-Related Lung Disease
The most common form of occupational and environmental lung disease is asthma (Chapters 24 and 25). The UK government has reported that 750 000 people with asthma work in an environment that triggers their symptoms, and more than 3000 per year develop asthma as a result of workplace substances. While the most common cause of occupational asthma is isocyanates (e.g. paint and plastics), grain and f our dust are not far behind, and secondary smoking is most commonly reported to exacerbate symptoms. It is estimated that elimination of occupational asthma alone could have a benefi of up to £1 billion over 10 years; education and prevention are therefore key targets. Atmospheric pollution in the form of car exhausts, diesel particulates and smoke, particularly by main roads and in cities, exacerbates symptoms of respiratory disease and can lead to increased mortality in the vulnerable and elderly.

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