University:
Glendale Community College
Course:
BIO160 | Introduction to Human Anatomy and Physiology
Academic year:

2022
Views:

61

Pages:

18
Author:

Dexter Hawkins

Organs of the Respiratory System Normal Frontal Chest X-ray • Airflow – nasal/oral cavity  trachea  bronchi  bronchioles  alveoli • Conducting Part – are passages for airflow • Respiratory Part – alveoli are the only place where significant gas-exchange takes place • Upper respiratory tract – organs in head and neck including the nose to the larynx • Lower respiratory tract – organs of the thorax: trachea to alveoli in the lungs Nose and Nasal Cavity • Functions – warms, cleanses, humidifies inhaled air – detects odors – resonating chamber that affects tone and amplifies the voice • Bony and Cartilaginous parts of the Nose – Nasal Bones of the skull – Nasal Cartilages are composed of hyaline cartilage which is less flexible than the elastic cartilage of external ear or epiglottis – Ala Nasi: flared portion around external nares (nostrils) are composed of dense connective tissue. Anatomy of Nasal Region Nasal Cavity - Conchae and Meatuses • Superior, Middle, Inferior Nasal Conchae – 3 folds of mucous membrane cover the nasal concha (turbinate bones) – mucus membrane is a ciliated pseudostratified epithelium with goblet cells – mucous traps inhaled particles and cilia sweeps it towards the pharynx – lysozyme released with mucus destroys many bacteria – submucosa over each concha contains a venous plexus called a swell body that rhythmically engorges with blood and shifts flow of air from one side to the other once or twice an hour to prevent drying • Meatuses – air passage between the conchae – narrowness and turbulence ensures air contacts mucous membranes • turbulence and large surface area facilitate cleaning and adjusting the temperature and humidity of the incoming air. superior nasal concha middle nasal concha inferior nasal concha Nasal Cavity Mucosa • Ciliated Pseudostratified Epithelium with Goblet Cells – moves debris-laden mucus into pharynx to be swallowed – Spontaneous Epistaxis (nosebleed) can occur if this epithelium dries out or in rare cases it can be a sign of hypertension. • Olfactory receptor neurons extend dendrites into the nasal mucus and extend axons up through the holes in the cribriform plate of ethmoid bone where they synapse with olfactory bulb neurons of Cranial Nerve I. • Olfactory receptor neurons are the only neurons in the body directly exposed to the external environment. • Unlike other neurons, the olfactory receptor neurons are replaced about every 60 days from basal cells that continually divide and differentiate into new olfactory receptor neurons. Pharynx (FAIR-inks) • Nasopharynx (ciliated pseudostratified epithelium) – contains the openings of the auditory tubes (Eustachian tubes) that equalize pressure between the atmosphere and the middle ear – contains pharyngeal tonsils (adenoids) • Oropharynx (stratified squamous epithelium) – space between soft palate and root of tongue – contains palatine tonsils and lingual tonsil • Laryngopharynx (stratified squamous epithelium) – posterior to larynx Regions of the Pharynx pharyngeal tonsils (adenoids) opening of auditory tubes palatine tonsil lingual tonsil Larynx (LAIR-inks) • Glottis is the superior opening of larynx • Epiglottis – flap of tissue that guards glottis, directs food and liquid into the esophagus – core of elastic cartilage makes it very flexible • Laryngeal Cartilages are composed of hyaline cartilage – Thyroid Cartilage - largest, has laryngeal prominence – Cricoid Cartilage – ring between thyroid cartilage and the trachea – Cartilages associated with vocal cords: • Arytenoid cartilages (2) • Corniculate cartilages (2) • Cuneiform cartilages (2) • Shape and size of the larynx affects tone of voice Epiglottis Glottis Larynx Cartilages of the Larynx Vocal Cords • False Vocal Cords (Vestibular Folds) are superior to the vocal cords and normally close the glottis during swallowing. • Vocal Cords: cords of connective tissue under the laryngeal mucosa that run from the tips of the arytenoid cartilages to the thyroid cartilage. – Air moving past the vocal cords causes them to vibrate and produce sound – Velocity of the air and tension on the cords varies the pitch • Intrinsic muscles - rotate cartilages that tighten vocal cords for high pitch sound or loosens vocal cords for low pitch sound • Extrinsic muscles - connect larynx to hyoid bone, elevate larynx during swallowing Laryngoscopic View of Larynx Action of Vocal Cords Adduction stretches vocal cords and produces high pitch sound Abduction moves vocal cords apart and produces a lower pitch Laryngeal Video Recordings