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Lab # 5. The Respiratory System 1. Functions of Respiratory System. 1- O 2 and CO 2 exchange between blood and air. 2- Speech and other vocalizations (laughing, crying). 3- It provides the sense of smell. 4- It helps to control the pH of body fluids by eliminating CO 2.
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Lab # 5 The Respiratory System 1
Functions of Respiratory System • 1- O2 and CO2 exchange between blood and air 2- Speech and other vocalizations (laughing, crying) 3- It provides the sense of smell 4- It helps to control the pH of body fluids by eliminating CO2 • 5- It helps to regulate blood pressure by synthesis of a vaso-constrictor called angiotensin II • 6- Breathing creates pressure gradients between thorax and abdomen that promote the flow of lymph and venous blood 7- Breath-holding helps expel abdominal contents during urination, defecation, and childbirth
Principal Organs of the Respiratory System Nose Pharynx Larynx Trachea Lungs Bronchi
The Nasal Cavity Meatuses: Functions of the nose • 1- It warms, cleanses, and humidifies inhaled air Superior Nasal conchae: Middle • 2- It detects odors in the airstream Inferior • 3- It serves as a resonating chamber that amplifies the voice Superior Posterior nasal aperture Middle Inferior Vestibule The respiratory epithelium lines the rest of nasal cavity except vestibule. It is a ciliated pseudostratified columnar epithelium with goblet cells
The Pharynx Nasopharynx • (posterior to nasal apertures and above soft palate) Pharyngeal tonsil Auditory tube Oropharynx (space between soft palate and epiglottis) Palatine tonsil Laryngopharynx • (from the epiglottis to the cricoid cartilage)
The Larynx It is a cartilaginous chamber about 4 cm (1.5 in.) 1- To keep food and drink out of the airway Functions: • 2- Production of sound (phonation) Epiglottis Epiglottis It closes the airway during swallowing Hyoid bone Epiglottic cartilage Hyoid bone Thyroid cartilage Thyroid cartilage Arytenoid cartilage Corniculate cartilage Vestibular fold Vocal cord Cricoid cartilage Arytenoid cartilage Cricoid cartilage Trachea Tracheal cartilage (a) Anterior (b) Posterior (c) Median
The Larynx Vestibular fold They play no role in speech but close the larynx during swallowing Vocal cord (from the thyroid cartilage to the arytenoid cartilage) They produce sound when air passes between them Median
The Trachea The trachea (windpipe) is a rigid tube about 12 cm (4.5 in.) long and 2.5 cm (1 in.) in diameter. • It is found anterior to the esophagus and it is supported by 16 to 20 C-shaped rings of hyaline cartilage, which reinforces the trachea and keeps it from collapsing when you inhale Trachea Ciliated pseudostratified columnar epithelium with goblets cells
Mucociliary escalator It is a mechanism that moves debris-laden mucus to the pharynx to be swallowed Ciliated pseudostratified columnar epithelium with goblets cells Goblet cell Ciliated cell Mucus Mucous gland
The Lungs They are conical organs with a broad, concave base, resting on the diaphragm, and a blunt peak called the apex projecting slightly above the clavicle Apex of lung Superior lobe Costal surface Superior lobe Horizontal fissure Middle lobe Mediastinal surface Oblique fissure Oblique fissure Inferior lobe Inferior lobe Diaphragmatic surface Base of lung
Bronchial Tree Thyroid cartilage All bronchi are lined with ciliated pseudostratified columnar epithelium Larynx Cricoid cartilage • The lamina propria has an abundance of mucous glands and lymphocyte nodules (bronchus-associated lymphoid tissue, BALT) positioned to intercept inhaled pathogens Trachea Carina Main bronchi (primary) Superior lobar bronchus Superior lobar bronchus (secondary) Middle lobar bronchus Inferior lobar bronchus (secondary) Inferior lobar bronchus Segmental bronchi (tertiary) Segmental bronchi (8 on left) (10 on right) Bronchopulmonary segment: It is a functionally independent unit of the lung tissue
Conducting Division of Respiratory System Main bronchus (lung) It consists of those passages that serve only for airflow: 1- Nostrils 2- Nasal cavity 3- Pharynx 4- Larynx Lobar bronchus 5- Trachea 6- Main (primary) bronchi (lungs) (lobe) 7- Lobar (secondary) bronchi (lobes) 8- Segmental (tertiary) bronchi (segments) 9- Bronchioles (lobules) 10- Terminal bronchioles (the final branches) Bronchioles and terminal bronchioles lack of supportive cartilages) Segmental bronchus Respiratory Division of Respiratory System (segment) Bronchiole (pulmonary lobule) It consists of those structures that participate in gas exchange Terminal bronchioles 1- Respiratory bronchioles 2- Alveolar duct (final branches of conducting division) 3- Atrium 4- Alveoli
Pulmonary venule Pulmonary arteriole Openings of alveolar ducts Bronchiole Alveolar sac Terminal bronchioles Respiratory bronchioles Every respiratory bronchiole divides into 2 to 10 alveolar ducts, which end in the alveolar sac Alveoli
The Respiratory Membrane O2 O2 O2 Squamous alveolar cell O2 O2 CO2 O2 CO2 CO2 Respiratory membrane Shared basement membrane Capillary endothelial cell CO2 CO2
Epithelium Type Changes in the Respiratory System Nasal cavity Ciliated pseudostratified columnar epithelium Nasopharynx Ciliated pseudostratified columnar epithelium Oropharynx Stratified squamous epithelium Laringopharynx Stratified squamous epithelium Larynx (superior part) Stratified squamous epithelium Larynx (inferior part) Ciliated pseudostratified columnar epithelium Trachea Ciliated pseudostratified columnar epithelium Bronchi Ciliated pseudostratified columnar epithelium Bronchioles Ciliated simple columnar epithelium Terminal bronchioles Simple cuboidal epithelium Alveoli Simple squamous epithelium (with 5% of round or cuboidal cells (type II alveolar cells)