Anatomical And Physiological of respiratory system Dr. Kareema Ahmed Hussein 2017 -2018

Functions of the respiratory system Gas exchange between air and circulating blood Moving air from the exchange surface of the lungs Protection of respiratory surfaces Production of sound Provision for olfactory sensations

Organization of the respiratory system 1.Upper respiratory system Nose, nasal cavity, paranasal sinuses, pharynx 2.Lower respiratory system Larynx, trachea, bronchi, bronchioles, alveoli

The Nose The only externally visible part of the respiratory system Air enters the nose through the external part of the nose The interior of the nose consists of a nasal cavity divided by a nasal septum

Anatomy of the Nasal Cavity/ function Olfactory receptors are located in the mucosa on the superior surface The rest of the cavity is lined with respiratory mucosa Moistens air Traps incoming foreign particles The nasal cavity is separated from the oral cavity by the palate Anterior hard palate (bone) Posterior soft palate (muscle)

Para- nasal Sinuses Cavities within bones surrounding the nasal cavity Frontal bone Sphenoid bone Ethmoid bone Maxillary bone

Nose

Function of the sinuses Lighten the skull Act as resonance chambers for speech Produce mucus that drains into the nasal cavity

Pharynx (Throat) Muscular passage from nasal cavity to larynx Three regions of the pharynx Nasopharynx – superior region behind nasal cavity Oropharynx – middle region behind mouth Laryngopharynx – inferior region attached to larynx The oropharynx and laryngopharynx are common passageways for air and food

Pharynx

Pharynx

Structures of the Larynx 1.Thyroid cartilage Largest hyaline cartilage Protrudes interiorly (Adam’s apple) 2.Epiglottis Superior opening of the larynx Routes food to the larynx and air toward the trachea 3.Glottis – opening between vocal cords

Vocal Folds and Ligaments

Trachea Tubular air passage way ~12cm long, 2.5cm diameter 16-20 incomplete ‘C’-shaped hyaline cartilage rings provide rigidity Open part of each ring faces posterior to esophagus Allows for esophageal expansion during swallowing Transverse smooth muscle (tracheal) and elastic connective tissue attach open ends of cartilage rings

Primary Bronchi Formed by division to the trachea Enters the lung at the hills(medial depression) Right bronchus is wider, shorter , and straighter than left Bronchi subdivide into smaller and smaller branches

The Anatomy of the Trachea

Lungs Occupy most of the thoracic cavity Apex is near the clavicle (superior portion) Each lung is divided into lobes Left lung – two lobes Right lung – three lobes

Conducting Zones

Coverings of the Lungs Pulmonary pleura covers the lung surface Parietal pleura lines the walls of the thoracic cavity Pleural fluid fills the area between layers of pleura to allow gliding

Alveoli Structure of alveoli Alveolar duct Alveolar sac Alveolus Gas exchange takes place within the alveoli in the respiratory membrane muamcous epithelial lining alveolar walls Covered with pulmonary capillaries on external surfaces

Blood Supply To The Lung Two separate blood supplies: pulmonary circulation and bronchial circulation

Pulmonary circulation Brings deoxygenated blood from the right ventricle to the gas-exchange units At the gas-exchanging units, oxygen is picked up and carbon dioxide is removed from the blood The oxygenated blood returned to the left atrium for distribution to the rest of the body

Gas Transport in the Blood 1.Oxygen transport in the blood Inside red blood cells attached to hemoglobin (oxyhemoglobin [HbO2]) A small amount is carried dissolved in the plasma 2.Carbon dioxide transport in the blood Most is transported in the plasma as bicarbonate ion (HCO3–) A small amount is carried inside red blood cells on hemoglobin.

Bronchial circulation Arise from the aorta Provides nourishments to the lung

Muscles of Respiration Inspiration/Inhalation Diaphragm & Intercostals muscles contract downward Increases volume in thoracic cavity as muscles contract Volume of lungs increases Intrapulmonary pressure decreases inspiration is active and air goes in

Expiration/Exhalation Diaphragm relaxes upward Intercostals muscles relaxes to Volume of thoracic cavity decreases Volume of lungs decreases Intrapulmonary pressure increases Forced expiration is active

Respiratory Rate Changes Throughout Life Newborns – 40 to 80 breath/ min. Infants – 30 breath/ min. Age 5 – 25 breath/ min Adults – 12 to 18 breath/ min Rate often increases with old age

Factors Influencing Respiratory Rate and Depth 1.Physical factors Increased body temperature Exercise Talking Coughing 2.Emotional factors

3.Chemical factors a. Carbon dioxide levels Level of carbon dioxide in the blood is the main regulatory chemical for respiration Increased carbon dioxide increases respiration Changes in carbon dioxide act directly on the medulla oblongata

Chemical factors (continued) b. Oxygen levels Changes in oxygen concentration in the blood are detected by chemoreceptors in the aorta and carotid artery Information is sent to the medulla oblongata

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