Historlogy Of The Resoritory System

Question 1

Functions of the respritory system

Answer 1

Gas exchange (primary function), olfaction, and phonation (production of sound)

Question 2

Conditioning

Answer 2

As air travels to site of gas exchange it is warmed humidified and cleared of particulate matter in this process which is known as conditioning

Question 3

Conduction portion of respritory system

Answer 3

Begins at the nares and consists of all air passages that lead to site of gas exchange in lungs, air is conditioned as it passes through conduction portion of respritory system

Question 4

Nasal Cavity respritory system

Answer 4

Air enters through nares and into nasal vestibule (lined by stratified squamous epithelium, contains hairs to entrap large particulate matter). Respritory portion nasal cavity lined by respritory mucosa which consists of ciliated pseudostratified columnar epithelium has thin underlying lamina propria. Epithelium consists of two cell types ciliated and goblet

Question 5

Ciliated cells of respritory system

Answer 5

Tall and columnar with cilia that project and into mucus covering epithelial surface

Question 6

Goblet cells of respritory system

Answer 6

Synthesize and secrete mucus have a distended apical cytoplams packed with mucinogen granules, stem portion is occupied by condensed basal nucleus and other organelles involved in synthesis of mucinogen (mucinogen washed out in H&E staining)

Question 7

Lamina propria respritory system

Answer 7

Underlying respritory epithelium, has rich vascular network which warms inspired air, also contains serous and mucous glands which secrete fluid and mucus onto epithelial surface

Question 8

Conchae

Answer 8

Cartilagenous scrolls that are covered in mucosa these project from dorsal and lateral walls of nasal cavity and increase its surface area. These increase efficiency of warming inspired air and turbine precipitation of particulate matter (air enters conchae breaks into eddies trapping particles of air in mucous covering epithelium, these particles are transported to the pharynx via coordinated sweeping movements of cillia where they can be swallowed or expectorated

Question 9

Pharynx

Answer 9

Air passes from nasal cavity into nasopharynx and laryngopharynx which are lined by respritory epithelium. Lamina propria form tonsils from gland and lymphoid tissue

Question 10

Larynx

Answer 10

Forms passage of air between oropharynx and trachea, mostly lined with ciliated pseudostratified columnar epithelium. Vocal folds and epiglottis are covered by stratified squamous epithelium

Question 11

Trachea

Answer 11

Consists of 4 tunics tunica mucosa, tunica submucosa, tunica muscularis, tunica adventitia

Question 12

Trachea tunica mucosa

Answer 12

Ciliated pseudostratified columnar epithelium, supported by elastic fiber rich lamina propria. NO clear boundary between lamia propria and submucosa

Question 13

Trachea tunica submucosa

Answer 13

Denser connective tissue than lamina propria
Submucosa contains serous (or seromucous glands depending on the species) and blood vessels which aid in warming and humidifying air. Very cellular, many lymphocytes, plasma cells, eosinophils, mast cells, and fibroblasts. Lymphatic tissue in diffuse and nodular forms

Question 14

Tunica muscularis trachea

Answer 14

Contains c shaped cartiledges open dorsally which keep lumen of trachea open. Open ends of cartilage rings are bridged by smooth muscle and elastic fibers

Question 15

Tunica adventitia

Answer 15

Connective tissue binding trachea to adjacent structures

Question 16

Tracheal epithelium

Answer 16

Contains ciliated and goblet cells that make up mucocilliary escalator where particles are entrapped by mucus and swept toward pharynx by coordinated movement of cillia. There is a population of basal cells which are pro generators of other cell types

Question 17

Bronchi

Answer 17

Trachea bifurcates into left and right primary bronchi, when entering the hilum of the lung each main bronchi divides into lobar bronchi, each of which enter a lung lobe, within each lobe these further divide to become segmental bronchi

Question 18

Bronchi histology

Answer 18

Very similar to that of trachea can be identified bc of cartilage plates and circular layer of smooth muscle as bronchi decrease in diameter with each division cartilage plates become smaller and less numerous and cells of epithelium become shorter

Question 19

Bronchioles

Answer 19

Air conducting ducts <1mm diameter, formed by branching of segmental bronchi, ducts branch and give rise to terminal bronchioles and ultimately respritory bronchioles. No cartilage or glands, thick layer of smooth muscle
Transition from ciliated pseudostratified columnar epithelium with goblet cells in large diameter bronchioles, to simple ciliated columnar epithelium, finally simple ciliated cubodial epithelium in smallest conducting bronchioles

Question 20

Cell clubs

Answer 20

Aka bronchiole exocrine cells Present in epithelium of terminal bronchioles non-ciliated cells with rounded or dome shaped apical surface projection secrete surface-active agent which keeps airway from adhering to itself should it collapse, also make other components of airway secretions and detoxify substance inhaled into lungs. # ciliated cells decreased # club cells increase

Question 21

Respritory bronchioles

Answer 21

Terminal bronchioles branch into respritory bronchiles which are first part of bronchial tree to allow gas exchange (these are involved in air conduction and gas exchange). Narrow in diameter and lined with cuboidal epithelium composed of ciliated and club cells. Scattered alveoli extend from lumen of respritory bronchioles

Question 22

Alveolar system

Answer 22

Alveoli are site of gas exchange, they are thin walled polyhedral chamber surrounded by capillary networks

Question 23

Alveolar ducts

Answer 23

Respritory bronchioles branch into alveolar ducts which consist of alveoli arranged to form tube. These terminate in alveolar sac

Question 24

Alveolar septum

Answer 24

Aka alveolar wall, tissue between adjacent alveolar air spaces

Question 25

Alveolar pores

Answer 25

Allow air spaces of neighboring alveoli to communicate

Question 26

Alveolar epithelium

Answer 26

Composed of type 1 and type 2 alveolar cells

Question 27

Type 1 alveolar cells

Answer 27

Thin squamous cell that allows for diffusion of o2 and co2 between blood and airspace

Question 28

Type 2 alveolar cells

Answer 28

Cuboidal cells that secrete surfactant which prevents collapse of alveoli upon exhalation, also serve as progenitor cells for alveolar epithelium

Question 29

Alveolar macrophages

Answer 29

Derived from blood monocytes, present in both air space of alveolus and connective tissue of septum, dispose of particulate matter some engorged macrophages pass up bronchial tree as mucus and are disposed of via spit or swallowing others remain in connective tissue

Question 30

Blood gas barrier

Answer 30

Gas exchange occurs between air in alveolar space and between erythrocytes in capillaries. Blood gas barrier are cells and cell products gasses must diffuse across between alveolar and capillary compartments

Question 31

Thin blood gas barrier

Answer 31

Thinnest consists of thin layer of surfactant, type 1 pneumocystis, fused basement membrane of pneumocyte, capillary endothelium, and capillary endothelial cell

Question 32

Pulmonary circulation

Answer 32

Derived from pulmonary artery supplies capillaries of alveolar septum via branching

Question 33

Bronchial circulation

Answer 33

Supplies all lung tissue other than alveoli, derives from bronchial arteries

Question 34

Pulmonary and bronchial circulations

Answer 34

Anastomoses at about the level between the junction between conducting and respritory passages

Question 35

Lymphatic vessel

Answer 35

Parenchyma of lungs drained by set of lymphatic vessels following course of air passages to hilum. Surface of lung drained by set of lympathatics that travel in connective tissue of visceral pleura

Question 36

Nerves

Answer 36

Nerves that serve lungs are components of ANS, mediate reflexes that modify dimensions of air passages and blood vessels via smooth muscle contractions, influence glandular secretion of respritory mucosa

Question 37

Visceral pleura

Answer 37

Mesothelium with its supporting connective tissue makes this up

Question 38

Mesothelium

Answer 38

Simple squamous epithelium that covers outer surface of each lung

Question 39

Interlobular septa

Answer 39

Connective tissue of visceral pleural which extends into the lungs, continuous with fibroelastic tissue which supports tubes and alveoli of lungs contains small blood vessels and lympatics