THE RESPIRATORY SYSTEM II Dr. Mah Jabeen Muneera Assistant professor Department of Anatomy KEMU

 Additional function:  Phonation  Prevent food/drinks – respiratory system  Tube : cartilage (hyaline, elastic) – ligaments – skeletal muscles (intrinsic- extrinsic)  Mucosa  Epihelium  Stratified squamous non keratinized epithelium  Pseudostratified (respiratory epithelium)  Lamina propria:  Connective tissue, lymphatic nodules, seromucous glands  Vestibular fold – false vocal cord (superior)  Vocal fold - true vocal cord (inferior) - stratified squamous  Vocalis muscle  vocal ligament – regular dense elastic CT Larynx – voice box

4

 Leaf shaped  Elastic cartilage  Mucosa on both sides  Lingual surface, upper laryngeal; stratified squamous epithelium  Lower half respiratory  Lamina propria; seromucous glands, more on laryngeal surface reside in Pock marks  Taste buds Epiglottis

Trachea–extrapulmonary bronchus  Mucosa  Respiratory epithelium – pseudostratified ciliated columnar epithelium with goblet cells  Lamina propria – thin, elastic fibers, Blood vessels, lymphoid tissue  Submucosa Dense irregular, fibroelastic connective tissue Mucous-seromucous glands Lymphoid tissue  Cartilage: C shaped hyaline cartilage  fibrous connective tissue  smooth muscle ; Trachealis  Adventitia – fibroelastic connective tissue

8

Trachea

BRONCHIAL TREE  Primary bronchi  Secondary (lobar) bronchi  Tertiary (segmental) bronchi  9-12 generations of branching  Bronchioles- 1mm diameter, supply a lung lobule  Terminal bronchiole  Respiratory bronchiole  Divide 2-3 times  Alveolar ducts  Atria  Alveolar sac  Alveoli

PRIMARY BRONCHUS  Closely resemble trachea  MUCOSA:  SUBMUCOSA: similar to trachea  CARTILAGE : COMPLETE ring  ADVENTITIA: similar to trachea

SECONDARY BRONCHUS  MUCOSA:  SUBMUCOSA: similar to trachea  At junction of mucosa & submucosa: SMOOTH MUSCLES & elastic fibers  CARTILAGE:  Broken pieces  ADVENTITIA

TERTIARY BRONCHUS  MUCOSA  EPITHELIUM-  Simple columnar ciliated  FEW goblet cells  SMOOTH MUSCLES  SUBMUCOSA  FEW seromucous glands  CARTILAGE  FEW pieces  ADVENTITIA

BRONCHIOLES  Diameter5mm or less  MUCOSA  Columnar ciliated with some goblet cells  Clara cells  Neuroepithelial bodies  Prominent smooth muscles  SUBMUCOSA  Elastic fibers  NO glands & lymph nodes  CARTILAGE : ABSENT  ADVENTITIA: thin

APPLIED ANATOMY  Smooth muscles under control of  Sympathetic system –relax smooth muscle –dilate bronchi  Parasympathetic system (Vagus nerve) –constrict bronchi  Increased airway resistance is due to contraction of bronchiolar smooth muscles  Epinephrine (adrenaline) and other sympathomimetic drugs are given to relax bronchiolar smooth muscles during asthma

TERMINAL BRONCHIOLE  MUCOSA  Simple low columnar/cuboidal ciliated  NO goblet cells  Clara cells & neuroepithelial bodies  Smooth muscles  Elastic fibers  ADVENTITIA