The Department of Human anatomyThe Department of Human anatomy

Respiratory System

The The respiratory systemrespiratory system is the anatomical  is the anatomical system of an organism that introduces system of an organism that introduces respiratory gases to the interior and respiratory gases to the interior and performs gas exchange. In humans the performs gas exchange. In humans the respiratory system include airways, lungs, and respiratory system include airways, lungs, and the respiratory the respiratory muscles. Molecules of oxygen and carbon muscles. Molecules of oxygen and carbon dioxide are passively exchanged, by diffusion, dioxide are passively exchanged, by diffusion, between the gaseous external environment between the gaseous external environment and the blood. This exchange process occurs and the blood. This exchange process occurs in the alveolar region of the lungs in the alveolar region of the lungs

General Functions of Respiratory System:

1. O2 (oxygenoxygen)) and CO2 (carbon dioxidecarbon dioxide) exchange between blood and air

2. speech and vocalization 3. sense of smell 4. helps control acid base balance of

body 5. breathing movements help promote

blood and lymph flow

Main Organs: nose pharynx larynx trachea primary bronchi lungs: bronchioles alveoli/respiratory membrane

these organs can also be subdivided into:

upper respiratory tractNose-pharynx-larynx lower respiratory tractrespiratory organs of the thorax

Functional classifications:Functional classifications: ConductingConducting portion: transports air. portion: transports air.

RespiratoryRespiratory portion: carries out gas portion: carries out gas exchange.exchange.

respiratory bronchiolesrespiratory bronchioles alveolar ductsalveolar ducts air sacs called alveoliair sacs called alveoli

Upper respiratory tract is all conductingUpper respiratory tract is all conducting Lower respiratory tract has both Lower respiratory tract has both

conducting and respiratory portionsconducting and respiratory portions

Air passageways must be held open at all times

nasal passageways and throat follow passages in skull bones and cartilage

others held open by rings of cartilage

Nose separated from mouth by hard

and soft palate each nasal cavity is divided into

3 passageways by turbinates (choncae)

turbulent passageways to insure that all air makes contact with mucous membranes

membranes are heavily vascualrized

remove bacteria, debris and particles

warms and moisturizes air entering lungs

also contains receptors for smell

nasolacrimal ducts drain into nasal cavity

Paranasal sinuses:Paranasal sinuses: In four skull bonesIn four skull bones paired air spacespaired air spaces decrease skull bone weightdecrease skull bone weight warm and moisten air sound resonance

Named for the bones Named for the bones in which they are housed.in which they are housed.

frontal frontal ethmoidal ethmoidal sphenoidalsphenoidal maxillary maxillary

Communicate with the nasal cavity by ducts. Communicate with the nasal cavity by ducts. Covered with the same pseudostratified Covered with the same pseudostratified

ciliated columnar epithelium as the nasal ciliated columnar epithelium as the nasal cavity.cavity.

Pharynx (throat)

- Is situated from base of skull to junction with esophagus and trachea

- made of muscle and lined with mucous membrane

- junction between digestive and respiratory systems

divided into three regions:a. Nasopharynx behind nose to level of soft palate includes uvula, tonsils (adenoids) auditory tube (eustachian tube)b. Oropharynx behind mouth from soft palate to level of hyoid bone palatine and lingual tonsilsc. Laryngopharynx from hyoid bone to esophagus/larynx

Larynx (voice box) enlarged beginning portion of trachea composed of cartilage and muscles opening into larynx = glottis (prevent

food from entering lower respiratory system

sound)

9 cartilages: three individual piecesthree individual pieces

Thyroid cartilageThyroid cartilage Cricoid cartilageCricoid cartilage EpiglottisEpiglottis

three cartilage pairsthree cartilage pairs Arytenoids: on cricoidArytenoids: on cricoid Corniculates: attach to Corniculates: attach to arytenoidsarytenoids Cuniforms:in aryepiglottic foldCuniforms:in aryepiglottic fold

Sound ProductionSound Production Two pairs of ligamentsTwo pairs of ligaments Inferior ligaments, called Inferior ligaments, called vocal vocal

ligamentsligaments covered by a mucous membranecovered by a mucous membrane are “true vocal cords”are “true vocal cords”

they produce sound when air passes they produce sound when air passes between thembetween them

Superior ligaments, called Superior ligaments, called vestibular vestibular ligamentsligaments Covered by mucosaCovered by mucosa Are “false vocal cords” Are “false vocal cords”

no function in soundno function in soundproductionproduction protect the vocal folds. protect the vocal folds.

The vestibular folds attachThe vestibular folds attachto the corniculate cartilagesto the corniculate cartilages. .

The tension, length, The tension, length, and position of the vocal and position of the vocal folds determine the quality of the sound.folds determine the quality of the sound. Longer vocal folds produce lower soundsLonger vocal folds produce lower sounds More taunt, higher pitchMore taunt, higher pitch Loudness based on force of airLoudness based on force of air

Rima glottidisRima glottidis: opening between the vocal folds: opening between the vocal folds GlottisGlottis: rima glottidis and the vocal folds: rima glottidis and the vocal folds

Trachea extends from larynx to bronchi

(immediately anterior to the immediately anterior to the esophagus, inferior to the larynx, esophagus, inferior to the larynx, superior to the primary bronchi of superior to the primary bronchi of the lungsthe lungs)

surrounded by 15 to 20 15 to 20 “C” – shaped bands of cartilage ends joined by bands of muscle tissue (holds walls open, prevents collapse)

lined by pseudostratified ciliated columnar epithelium

At the level of the At the level of the sternal anglesternal angle, the , the trachea bifurcates into two smaller trachea bifurcates into two smaller tubes, called the tubes, called the right and left primary right and left primary bronchibronchi..

Each primary bronchus projects Each primary bronchus projects laterally toward each lung. laterally toward each lung.

The most inferior tracheal cartilage The most inferior tracheal cartilage separates the primary bronchi at their separates the primary bronchi at their origin and forms an internal ridge origin and forms an internal ridge called the called the carina.carina.

Bronchi bronchi resemble trachea in

structure (also supported by C-shaped cartilages)

also have lots of elastic connective tissue Right primary bronchusRight primary bronchus

shorter, wider, and more shorter, wider, and more vertically oriented than the left vertically oriented than the left primary bronchus. primary bronchus.

Foreign particles are more likely Foreign particles are more likely to lodge in the right primary to lodge in the right primary bronchus.bronchus.

each bronchus enters lung and continues to divide into smaller and smaller branches = bronchi, then into microscopic bronchioles

because of the extensive branching it formes bronchial tree

Primary bronchiPrimary bronchi enter the hilum of each lungenter the hilum of each lung Also entering hilum:Also entering hilum:

pulmonary vesselspulmonary vessels lymphatic vesselslymphatic vessels nerves. nerves.

Secondary bronchi (or lobar bronchi)Secondary bronchi (or lobar bronchi) Branch of primary bronchusBranch of primary bronchus left lung:left lung:

two lobestwo lobes two secondary bronchitwo secondary bronchi

right lungright lung three lobesthree lobes three secondary bronchi.three secondary bronchi.

Tertiary bronchi (or segmental bronchi)Tertiary bronchi (or segmental bronchi) Branch of secondary bronchi Branch of secondary bronchi left lung is supplied by 8 to 10 tertiary bronchi. left lung is supplied by 8 to 10 tertiary bronchi. right lung is supplied by 10 tertiary bronchiright lung is supplied by 10 tertiary bronchi supply a part of the lung called a supply a part of the lung called a

bronchopulmonary bronchopulmonary segment.segment.

Bronchioles smallest branches of “respiratory tree” <1mm diameter no cartilage rings (but larger branches may have

small patches of cartilage) lined with ciliated cuboidal epithelium and layer

of smooth muscle asthma affects the smallest terminal bronchioles

Respiratory Bronchioles, Alveolar Respiratory Bronchioles, Alveolar Ducts, and AlveoliDucts, and Alveoli

Contain small saccular outpocketings called Contain small saccular outpocketings called alveoli.alveoli.

An alveolus is about 0.25 to 0.5 millimeter An alveolus is about 0.25 to 0.5 millimeter in diameter. in diameter.

Its thin wall is specialized to promote Its thin wall is specialized to promote diffusion of gases between the alveolus and diffusion of gases between the alveolus and the blood in the pulmonary capillaries. the blood in the pulmonary capillaries.

Gas exchange can take place in the Gas exchange can take place in the respiratory bronchioles and alveolar ducts respiratory bronchioles and alveolar ducts as well as in the lungs, which contain as well as in the lungs, which contain approximately 300–400 million alveoli.approximately 300–400 million alveoli.

The spongy nature The spongy nature of the lung is due to the of the lung is due to the packing of millions of alveoli together.packing of millions of alveoli together.

Gross Anatomy of the Lungs Gross Anatomy of the Lungs Each lung has a conical shape. Each lung has a conical shape. Its wide, concave base rests upon the muscular Its wide, concave base rests upon the muscular

diaphragm.diaphragm. Its relatively blunt superior region, called the apex or Its relatively blunt superior region, called the apex or

(cupola), projects superiorly to a point that is slightly (cupola), projects superiorly to a point that is slightly superior and posterior to the clavicle. superior and posterior to the clavicle.

Both lungs are bordered by the thoracic wall Both lungs are bordered by the thoracic wall anteriorly, laterally, and posteriorly, and supported by anteriorly, laterally, and posteriorly, and supported by the rib cage. the rib cage.

Toward the midline, the lungs are separated from Toward the midline, the lungs are separated from each other by the mediastinum. each other by the mediastinum.

The relatively broad, rounded surface in contact with The relatively broad, rounded surface in contact with the thoracic wall is called the costal surface of the the thoracic wall is called the costal surface of the lung.lung.

Pleura and Pleural Cavities Pleura and Pleural Cavities The outer surface of each lung and the The outer surface of each lung and the

adjacent internal thoracic wall are lined by adjacent internal thoracic wall are lined by a serous membrane called pleura, which is a serous membrane called pleura, which is formed from simple squamous epithelium. formed from simple squamous epithelium.

The outer surface of each lung is tightly The outer surface of each lung is tightly covered by the visceral pleura, while the covered by the visceral pleura, while the internal thoracic walls, the lateral surfaces internal thoracic walls, the lateral surfaces of the mediastinum, and the superior of the mediastinum, and the superior surface of the diaphragm are lined by the surface of the diaphragm are lined by the parietal pleura. parietal pleura.

The parietal and visceral pleural layers are The parietal and visceral pleural layers are continuous at the hilum of each lung. continuous at the hilum of each lung.

Pleura and Pleural CavitiesPleura and Pleural Cavities

The potential space between these The potential space between these serous membrane layers is a pleural serous membrane layers is a pleural cavity. cavity.

The pleural membranes produce a thin, The pleural membranes produce a thin, serous fluid that circulates in the serous fluid that circulates in the pleural cavity and acts as a lubricant, pleural cavity and acts as a lubricant, ensuring minimal friction during ensuring minimal friction during breathing.breathing.

Aging and the Respiratory Aging and the Respiratory System System

Becomes Becomes less efficientless efficient with age due to several with age due to several structuralstructural changes.changes.

Decrease in elastic connective tissueDecrease in elastic connective tissue in the lungs and the in the lungs and the thoracic cavity wall. thoracic cavity wall.

Loss of elasticity Loss of elasticity reducesreduces the amount of gas that can be the amount of gas that can be exchanged with each breath and results in a exchanged with each breath and results in a decreasedecrease in in the ventilation rate. the ventilation rate.

EmphysemaEmphysema may cause a loss of alveoli or their may cause a loss of alveoli or their functionality functionality

Reduced capacity for gas exchange can cause an older Reduced capacity for gas exchange can cause an older person to become “short of breath” upon exertion. person to become “short of breath” upon exertion.

Carbon, dust, and pollution material gradually Carbon, dust, and pollution material gradually accumulateaccumulate in our lymph nodes and lungs.in our lymph nodes and lungs.

Respiratory diseases can be classified in many Respiratory diseases can be classified in many different ways, including by the organ or tissue different ways, including by the organ or tissue involved, by the type and pattern of associated involved, by the type and pattern of associated signs and symptoms, or by the cause (etiology) of signs and symptoms, or by the cause (etiology) of the disease.the disease.

Inflammatory lung diseaseInflammatory lung diseaseCharacterised by a high neutrophil count, e.g. asthma, Characterised by a high neutrophil count, e.g. asthma,

cystic fibrosis, emphysema, chronic obstructive cystic fibrosis, emphysema, chronic obstructive pulmonary disorder or acute respiratory distress pulmonary disorder or acute respiratory distress syndrome.syndrome.

Allergic reactions due to exposure to certain agents Allergic reactions due to exposure to certain agents (i.e. foods) are a relatively common cause of acute (i.e. foods) are a relatively common cause of acute respiratory disease. Some common examples respiratory disease. Some common examples include sea foods prawns, some fatty fish, radish, include sea foods prawns, some fatty fish, radish, arrow root, lady's finger, lemon, moong dhal, arrow root, lady's finger, lemon, moong dhal, peanuts, water content spinach, curd, bananas, peanuts, water content spinach, curd, bananas, grapes, pomegranates, berries, custard apple, ice grapes, pomegranates, berries, custard apple, ice creams, etc. In summer, bad weather condition creams, etc. In summer, bad weather condition mean sandy and dusty weather or some may affect mean sandy and dusty weather or some may affect in winter also.in winter also.

Obstructive lung diseasesObstructive lung diseases Obstructive lung diseases are diseases of Obstructive lung diseases are diseases of

the lung where the airwaysthe lung where the airways (i.e. bronchi, bronchioles, alveoli) become (i.e. bronchi, bronchioles, alveoli) become reduced in volume or have free flow of gas reduced in volume or have free flow of gas impeded, making it more difficult to move impeded, making it more difficult to move air in and out of the lung.air in and out of the lung.

Chronic Obstructive Pulmonary Disease Chronic Obstructive Pulmonary Disease (COPD)(COPD)

Chronic Obstructive Pulmonary Chronic Obstructive Pulmonary Disease (COPD), which includes asthma an Disease (COPD), which includes asthma an example of an obstructive lung disease, is example of an obstructive lung disease, is where the airways become damaged, where the airways become damaged, causing them to narrow.causing them to narrow.

AsthmaAsthma Asthma is another example of an obstructive lung disease, Asthma is another example of an obstructive lung disease,

(and of an inflammatory lung disease).(and of an inflammatory lung disease). Asthma attacks can be brought on by triggers, such as air Asthma attacks can be brought on by triggers, such as air

pollution, tobacco smoke, factory fumes, cleaning solvents, pollution, tobacco smoke, factory fumes, cleaning solvents, infections, pollens, foods, cold air, exercise, chemicals and infections, pollens, foods, cold air, exercise, chemicals and medications. Triggers are highly individual and may not be medications. Triggers are highly individual and may not be related to allergens. Many asthmatics are not allergic to related to allergens. Many asthmatics are not allergic to common allergens such as mold, ragweed, dust or pollens.common allergens such as mold, ragweed, dust or pollens.

Restrictive lung diseasesRestrictive lung diseases Restrictive lung diseases (also known as interstitial lung Restrictive lung diseases (also known as interstitial lung

diseases) are a category of respiratory disease characterized diseases) are a category of respiratory disease characterized by a loss of lung compliance, causing incomplete lung by a loss of lung compliance, causing incomplete lung expansion and increased lung stiffness. E.g. in infant expansion and increased lung stiffness. E.g. in infant respiratory distress syndrome (IRDS).respiratory distress syndrome (IRDS).

Respiratory tract infectionsRespiratory tract infections Infections can affect any part of the respiratory system. They Infections can affect any part of the respiratory system. They

are traditionally divided into upper respiratory tract infections are traditionally divided into upper respiratory tract infections and lower respiratory tract infections.and lower respiratory tract infections.

Upper respiratory tract infectionUpper respiratory tract infection The most common upper respiratory tract infection is The most common upper respiratory tract infection is

the common cold however, infections of specific the common cold however, infections of specific organs of the upper respiratory tract such organs of the upper respiratory tract such as sinusitis, tonsillitis, otitis as sinusitis, tonsillitis, otitis media, pharyngitis and laryngitis are also considered media, pharyngitis and laryngitis are also considered upper respiratory tract infections.upper respiratory tract infections.

Lower respiratory tract infectionLower respiratory tract infection The most common lower respiratory tract infection in The most common lower respiratory tract infection in

is pneumonia, a lung infection. Pneumonia is usually is pneumonia, a lung infection. Pneumonia is usually caused by bacteria, particularlyStreptococcus caused by bacteria, particularlyStreptococcus pneumoniae in Western countries. pneumoniae in Western countries. Worldwide, tuberculosis is an important cause of Worldwide, tuberculosis is an important cause of pneumonia. Other pathogens such as viruses and pneumonia. Other pathogens such as viruses and fungi can cause pneumonia for example severe acute fungi can cause pneumonia for example severe acute respiratory syndrome and pneumocystis pneumonia. respiratory syndrome and pneumocystis pneumonia. A pneumonia may develop complications such as a A pneumonia may develop complications such as a lung abscess, a round cavity in the lung caused by lung abscess, a round cavity in the lung caused by the infection, or may spread to the pleural cavity.the infection, or may spread to the pleural cavity.

Respiratory tumorsRespiratory tumors Tumours of the respiratory system are Tumours of the respiratory system are

either malignant or benign.either malignant or benign. Malignant tumorsMalignant tumors Malignant tumors, or cancers of the Malignant tumors, or cancers of the

respiratory system, particularly lung respiratory system, particularly lung cancers, are a major health problem cancers, are a major health problem responsible for 15% of all cancer diagnoses responsible for 15% of all cancer diagnoses and 29% of all cancer deaths.and 29% of all cancer deaths.[3] The  The majority of respiratory system cancers are majority of respiratory system cancers are attributable to smoking attributable to smoking tobacco..