Respiratory System The Respiratory System l The respiratory

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Respiratory System

Respiratory System

The Respiratory System l The respiratory system works with the cardiovascular system to exchange

The Respiratory System l The respiratory system works with the cardiovascular system to exchange gases between the air and blood (external respiration) and between blood and tissue fluids (internal respiration). l Inspiration and expiration move air in and out of the lungs during breathing. l Cellular respiration is the final destination where ATP is produced in cells.

The respiratory tract

The respiratory tract

The Respiratory Tract l Air is cleansed, warmed, and moistened as it passes the

The Respiratory Tract l Air is cleansed, warmed, and moistened as it passes the cilia and mucus in the nostrils and nasal cavity. l In the nose, the hairs and the cilia act as a screening device. l In the trachea, the cilia beat upward, carrying dust and mucus into the pharynx. l Exhaled air carries out heat and moisture.

The Nose two nasal cavities are divided by a septum. l They contain olfactory

The Nose two nasal cavities are divided by a septum. l They contain olfactory cells, receive tear ducts from eyes, and communicate with sinuses. l The nasal cavities empty into the nasopharynx. l Auditory tubes lead from the middle ears to the nasopharynx. l The

The path of air

The path of air

The Pharynx l The pharynx (throat) is a passageway from the nasal cavities to

The Pharynx l The pharynx (throat) is a passageway from the nasal cavities to oral cavities and to the larynx. l The pharynx contains the tonsils; the respiratory tract assists the immune system in maintaining homeostasis. l The pharynx takes air from the nose to the larynx and takes food from the oral cavity to the esophagus.

The Larynx l The larynx is a cartilaginous structure lying between the pharynx and

The Larynx l The larynx is a cartilaginous structure lying between the pharynx and the trachea. l The larynx houses the vocal cords. l A flap of tissue called the epiglottis covers the glottis, an opening to the larynx. l In young men, rapid growth of the larynx and vocal cords changes the voice.

Placement of the vocal cords

Placement of the vocal cords

The Trachea l The trachea, supported by C-shaped cartilaginous rings, is lined by ciliated

The Trachea l The trachea, supported by C-shaped cartilaginous rings, is lined by ciliated cells, which sweep impurities up toward the pharynx. l Smoking destroys the cilia. l The trachea takes air to the bronchial tree. l Blockage of the trachea requires an operation called a tracheostomy to form an opening.

Cilia in the trachea

Cilia in the trachea

The Bronchial Tree l The trachea divides into right and left primary bronchi which

The Bronchial Tree l The trachea divides into right and left primary bronchi which lead into the right and left lungs. l The right and left primary bronchi divide into ever smaller bronchioles to conduct air to the alveoli. l An asthma attack occurs when smooth muscles in the bronchioles constrict and cause wheezing.

The Lungs l Lungs are paired, cone-shaped organs that lie on either side of

The Lungs l Lungs are paired, cone-shaped organs that lie on either side of the heart and within the thoracic cavity. l The right lung has three lobes, and the left lung has two lobes, allowing for the space occupied by the heart. l The lungs are bounded by the ribs and diaphragm.

The Alveoli l Alveoli are the tiny air sacs of the lungs made up

The Alveoli l Alveoli are the tiny air sacs of the lungs made up of squamous epithelium and surrounded by blood capillaries. l Alveoli function in gas exchange, oxygen diffusing into the bloodstream and carbon dioxide diffusing out. l Infant respiratory distress syndrome occurs in premature infants where underdeveloped lungs lack surfactant (thin film of lipoprotein) and collapse.

Gas exchange in the lungs

Gas exchange in the lungs

Mechanism of Breathing l During breathing, air moves into the lungs during inspiration (inhalation)

Mechanism of Breathing l During breathing, air moves into the lungs during inspiration (inhalation) from the nose or mouth, then moves out again during expiration (exhalation). l A spirometer allows measurement of the components of air during breathing.

Inspiration When we inhale (inspiration) impulses from the respiratory center in the medulla oblongata

Inspiration When we inhale (inspiration) impulses from the respiratory center in the medulla oblongata cause the rib cage to rise and the diaphragm to lower, causing the thoracic cavity to expand. l The negative pressure or partial vacuum in the alveoli causes the air to come in. l Changing amounts of blood of CO 2 and H+ increase breathing rate. l

Inspiration

Inspiration

Expiration When we exhale (expiration), lack of impulses from the respiratory center allow the

Expiration When we exhale (expiration), lack of impulses from the respiratory center allow the rib cage to lower and diaphragm to resume dome shape. l Expiration is passive, while inspiration is active. l The elastic recoil of the lungs causes expiration. l A deep breath causes alveoli to stretch; stretch receptors then inhibit the respiratory center. l

Expiration

Expiration

Gas Exchanges in the Body l External Respiration respiration is the diffusion of CO

Gas Exchanges in the Body l External Respiration respiration is the diffusion of CO 2 from pulmonary capillaries into alveolar sacs and O 2 from alveolar sacs into pulmonary capillaries.

l Most CO 2 is carried as bicarbonate ions. enzyme carbonic anhydrase, in red

l Most CO 2 is carried as bicarbonate ions. enzyme carbonic anhydrase, in red blood cells, speeds up the conversion of bicarbonate and H+ to H 2 O and CO 2; CO 2 enters alveoli and is exhaled. l The l Hemoglobin (Hb) takes up oxygen from alveoli and becomes oxyhemoglobin (Hb. O 2).

Internal Respiration l Internal respiration is the diffusion of O 2 from systemic capillaries

Internal Respiration l Internal respiration is the diffusion of O 2 from systemic capillaries into tissues and CO 2 from tissue fluid into systemic capillaries. l Oxyhemoglobin gives up O 2, which diffuses out of the blood and into the tissues because the partial pressure of O 2 of tissues fluid is lower than that of the blood.

l After CO 2 diffuses from tissue cells into the blood, it enters red

l After CO 2 diffuses from tissue cells into the blood, it enters red blood cells where a small amount is taken up by hemoglobin, forming carbaminohemoglobin.

External and internal respiration

External and internal respiration

Respiration and Health l The presence of disease in the upper or lower respiratory

Respiration and Health l The presence of disease in the upper or lower respiratory tract means that homeostasis is threatened. l Upper Respiratory Tract Infections l These infections involve the nasal cavities, pharynx, or larynx. l Some infections, such as “strep throat”, can lead to systemic body infection.

Sites of upper respiratory infections

Sites of upper respiratory infections

Sinusitis l Sinusitis is infection of the cranial sinuses within the facial skeleton that

Sinusitis l Sinusitis is infection of the cranial sinuses within the facial skeleton that drain into nasal cavities. l It occurs when nasal congestion blocks the sinus openings and is relieved when drainage is restored. l Pain and tenderness over the lower forehead and cheeks, and toothache, accompany this condition.

Otitis Media l Otitis media is bacterial infection of the middle ear. l Children

Otitis Media l Otitis media is bacterial infection of the middle ear. l Children suffer when a nasal infection spreads to the middle ear by way of the auditory tube and antibiotics are usually used to clear the infection. l Sometimes drainage tubes (called tympanostomy tubes) are inserted into the eardrums of children with recurrent infections. l

l Tonsillitis is infection of tonsils and recurrent infections that make breathing or swallowing

l Tonsillitis is infection of tonsils and recurrent infections that make breathing or swallowing difficult may be relieved by a tonsillectomy. l Laryngitis is an infection of the larynx and usually results in a loss of voice. l Persistent hoarseness is a warning sign of cancer.

Lower Respiratory Tract Disorders l Lower respiratory infections include: 1) acute bronchitis, an infection

Lower Respiratory Tract Disorders l Lower respiratory infections include: 1) acute bronchitis, an infection of primary and secondary bronchi; 2) pneumonia involving a bacterial or viral infection of the lungs; and 3) pulmonary tuberculosis (infection caused by tubercle bacillus).

Restrictive Pulmonary Disorders l In restrictive pulmonary disorders, vital capacity is reduced because the

Restrictive Pulmonary Disorders l In restrictive pulmonary disorders, vital capacity is reduced because the lungs have lost their elasticity due to inhaled particles such as silica, coal dust, or asbestos. l Fibrous connective tissue builds in the lungs in pulmonary fibrosis, caused by exposure to inhaled particles, including those of fiberglass.

Obstructive Pulmonary Disorders l In obstructive pulmonary disorders, air does not flow freely in

Obstructive Pulmonary Disorders l In obstructive pulmonary disorders, air does not flow freely in the airways, and inhalation and exhalation are difficult. l Chronic bronchitis with inflamed airways, emphysema where alveolar walls break down, and asthma with constricted bronchioles obstruct the airways and tend to get progressively worse or recur.

Lower respiratory tract disorders

Lower respiratory tract disorders

Lung Cancer l Lung cancer follows this sequence of events: thickening of airway cells,

Lung Cancer l Lung cancer follows this sequence of events: thickening of airway cells, loss of cilia on the lining, cells with atypical nuclei, tumor development, and finally metastasis. l Removal of a lobe or lung, called pneumonectomy, may remove the cancer. l Smoking, whether active or passive, is a major cause of lung cancer.

Normal lung versus cancerous lung

Normal lung versus cancerous lung