Respiratory System

Question 1

Functions of Respiratory System

Answer 1

*main: breathing - involves inhalation & exhalation

• Gas exchange
• Gas conduction (warmed, humidified, cleansed)
• Sound production
• Olfaction (olfactory epithelium)
• Defense (i.e. hairs w/in) nostrils - brisae)

Question 2

Division of Respiratory System;

• Anatomically
• Functionally

Answer 2

Anatomically; Can be divided into tracts:

i) Upper respiratory tract (nose to pharynx)
ii) Lower respiratory tract (larynx down to and including the lungs)

Functionally; the system can be divided into functional zones

i) Conducting zones (passageways that transport air; nose to terminal bronchioles)
ii) Respiratory zone: small airways dedicating to gas exchange (respiratory bronchioles to alveoli)

Question 3

Upper Respiratory Tract

Answer 3

Comprised of;

• nose and nasal cavities
• paranasal sinuses
• pharynx

*are all part of the conducting portion of respiratory system

Question 4

Lower Respiratory Tract

Answer 4

Comprised of:

• Larynx
• Trachea
• Bronchi
• Lungs

Question 5

Nose

Answer 5

• Is main conducting airway for inhaled air
• supported superiorly by paired nasal bones (form bridge of nose)
• Supported anteroinferiorly from the bridge by fleshy, cartilagenous dorsum nasi

Question 6

Nasal Cavity & associated structures;-

-conchae, nasal meatus, vestibule

Answer 6

• begins as internal component of nose, ends as openings to nasopharynx (CHOANAE)
• nasal septum divides nasal cavity into right & left portions
• shell like bony scrolls form lateral walls (superior, middle & inferior nasal conchae)
  
  • conchae = condition air in the spaces between (nasal meatus)
• anterior region of nasal cavity = vestibule
• lined w/ psuedostratified ciliated columnar epithelium
• most superior part = olfactory epithelium

Question 7

Paranasal sinuses - function & name (4)

Answer 7

• Four bones of the skull contain paired air sacs = paranasal sinuses
• make bones lighter in weight
• Frontal
• Ethmoidal
• sphenoidal
• maxillary

Question 8

Pharynx - features

-3 regions

Answer 8

*Shared by two organ systems - digestive & respiratory*
aka throat
-funnel shaped
-lined by mucosa
Divided into 3 regions;-
-Nasopharynx
-Oropharynx
-Laryngopharynx

Question 9

Nasopharynx

Answer 9

• most superior region
• conducts air
• lined w/ psuedostratified ciliated columnar epithelium
• Continous w/ nasal cavity & superior to soft palate
• opening of auditory tubes found in lateral walls
• posterior nasopharynx wall houses single pharyneal tonsil

Question 10

Oropharynx

Answer 10

• begins at end of soft palate & ends at lvl of hyoid bone
• opening of oral cavity into oropharynx = fauces (throat)
  
  • has 2 pairs of muscular arches on lateral walls
• conducts air & serves as passageway for food/air
• non-keratinized stratified squamous epithelium (strong enough to w/stand abrasion)
• lymphatic organs: First line of defense when foreign materials digested

Question 11

Laryngopharynx

Answer 11

• Starts inferior to hyoid bone - continuous w/ larynx and esophagus
• Same function & structure as oropharynx

Question 12

Lower Respiratory Tract (conducting portion)

Answer 12

Comprised of;-

• larynx
• trachea
• bronchi
• bronchioles - terminal

Question 13

Larynx

Answer 13

-(aka voicebox)
-continuous w/ larynopharynx
-supported by framework of cartilages, ligaments & muscles
FUNCTIONS: passageway for air, prevents ingested matter from entering, sound for speech, assist. in increasing pressure in ab. cavity, participates in sneeze & cough reflex
3 major cartilages:
1. Thyroid Cartilage
2. Cricoid cartilage
3. Epiglottis

Question 14

Major Cartilages of the larynx; Thyroid Cartilage

Answer 14

• largest cartilage
• has anterior & lateral wall only (shield shaped)
• V shaped anterior projection = laryngeal prominence (Adam’s Apple)
  
  • usu. larger in males due to testoterone’s influence on cartilage growth
• composed of hyaline cartilage

Question 15

Major Cartilages of the larynx: Cricoid Cartilage

Answer 15

• inferior to thyroid cartilage
• complete ring-shaped cartilage
• maintains openness of windpipe
• composed of hyaline cartilage

Question 16

Major cartilages of the larynx: Epiglottis

Answer 16

• Spoon shaped cartilage that projects superiorly into pharynx
• swallowing causes epiglottis to close opening - prevents materials entering lower respiratory tract
• made of more elastic elastic cartilage

Question 17

Sound Production

Answer 17

• vocal folds found in larynx comprised of vocal ligaments covered by mucous membrane
• opening b/w vocal folds = rima glottidis
• vocal folds + rima glottidis = glottis
• when air forced through rima glottidis, causes vibration of vocal folds = sound

Question 18

Trachea

Answer 18

aka windpipe

• inferior to larynx, superior to primary bronchi, anterior to oseophagus
• 12-14cm in length
• supported by C-shaped tracheal cartilages (to help maintain & keep trachea open)
• mucosa lined w/ psuedo-stratified columnar epithelium & mucin-secreting goblet cells (helps humidify air & trap debris)
• bifurates into 2 smaller tubes = bronchi
  
  • ridge where they separate = carina

Question 19

Bronchial Tree

Answer 19

• highly branched system
• begin w/ primary bronchi & end w/ terminal bronchi
• belong to conducting portion
• reside w/in substance of lungs
• branches into left & right primary bronchi @ carina
  
  • right wider & more vertical - divides into 3 secondary bronchi
  • left divides into 2 secondary bronchi
• secondary bronchi divide into 8-10 tertiary bronchi (or segmental/lobar)

Question 20

Patterns observed in structure as Bronchial tree divides

Answer 20

• incomplete rings of cartilage becomes smaller and less numerous
• all bronchi lined w/ pesudostratified columnar epithelium to trap debris
• bronchi branch into bronchioles - these lack rings and lined with simple columnar or simple squamous epithelium

Question 21

Bronchioles

Answer 21

• less than 1 mm in diameter
• walls composed of relatively thick layer of smooth muscle
• contraction of muscles = narrowing of brionchioles = bronchoconstriction (aka asthma)
• relaxation of muscles = bronchodilation
• branch into terminal bronchioles - are last part of of conducting portion

Question 22

Respiratory Portion of respiratory system

Answer 22

• respiratory bronchioles
• aveolar ducts & sacs
• pulmonary alveoli

Question 23

Structures between terminal bronchioles -> alveolus

Answer 23

• Terminal bronchioles branch into respiratory bronchioles
• respiratory bronchioles branch into alveolar ducts
• alveolar ducts end w/ small saccular outpocketings called alveoli
• thin walls of alveolus is where respiratory gases diffuse

Question 24

Alveolus - 2 types of cells

-alveolar macrophages

Answer 24

Walls formed by 2 types of cells;-

• Alveolar type 1 cells: simple squamous (majority - is where gas exchange occurs)
• Alveolar type 2 cells: almost cuboidal (produce pulmonary surfactant - decreases surface tension w/in alveolus and prevents collpase of alveoli

-alveolar macrophages: engulf any microorganism or particulate matter that makes it way into alveolus

Question 25

Respiratory Membrane - function -3 components

Answer 25

-Is the diffusion barrier across which respiratory gases exchanged between blood and air in alveoli Consists of: -plasma membrane of type 1 alveolar cells -plasma membrane of capillary cell -fused basement membrane of both cells

Question 26

Pleura - what it is - cell type - visceral vs parietal - pleural cavity

Answer 26

-Pleura = serious membrane that lines outer lung surface & adjacent thoracic wall -formed from simple squamous epithelium (called mesothelium) VISCERAL PLEURA: outer surface of lung PARIETAL PLEURA: interior thoracic wall, lateral mediostinum and superior surface of diaphragm -secrete serious fluid - for lubrication & tension b/w pleural membranes Pleural cavity: space b/w visceral and parietal cavities

Question 27

Lungs - shape - hilum

Answer 27

-conical in shape - base inferiorly rests on diaphragm, apex = superior most portion -apex projects slightly superior and posterior to clavicle -costal surface comes in contact w/ ribs mediastinal surface housed concaver region = hilum (is where bronchi, pulmonary vessels, lymphatic vessels & nerves pass into and out of lungs -hilum and its structures = root of lung

Question 28

Left lung vs right lung

Answer 28

Left Lung: -slightly smaller (due to heart projecting) -heart makes indentation on medial surface = cardiac impression/cardiac notch -oblique fissure - divides lungs into 2 LOBES (superior & inferior) Right Lung: -2 fissures (oblique & horizontal) -divided into 3 LOBES (superior, middle & inferior)

Question 29

Blood supply to & from lungs -Pulmonary and bronchial circulation

Answer 29

- pulmonary circulation conducts blood to and from gas exchange surfaces of the lungs - Bronchial circulation is a component of systemic circulation that delivers blood directly to and from bronchi and bronchioles - is what actually oxygenates lungs

Question 30

Pulmonary Ventilation - what is it - what happens during inhalation & exhalation in terms of; - volume, pressure and air flow

Answer 30

``` (AKA breathing) -Is the movement of air into and out of respiratory system -movement of gases follows Boyle's law (pressure) Inhalation: -volume of thoracic cavity increases -intrapulmonary pressure decreases -air flows into lungs Exhalation: opposite of inhalation ```

Question 31

Thoracic wall dimension changes during respiration

Answer 31

-during inhalation & exhalation, thoracic cavity changes in 3 dimensions; - Vertically: movement of diaphragm - Lateral: rib cage is elevated and thoracic cavity widens (or rib cage depresses) - Anterior/posterior: inferior position of sternum moves anteriorly and then posteriorly

Question 32

Muscles of Respiration

Answer 32

- External intercostals: elevates ribs during inhalation - Internal intercostals: depresses ribs during forced exhalation - Diaphragm: major muscle of respiration

Question 33

Diaphragm

Answer 33

- Internal dome-shaped muscle that physically separates thoracic and abdominopelvic cavities - possesses central tendon - all of its fibres converge (has holes that allows diff. structures to pass through) - Contraction of diaphragm causes a depression of muscle, thus increasing the vertical dimensions of thoracic cavity

Question 34

4 continuous and simultaneous process of gas exchange

Answer 34

1. Pulmonary ventilation: movement of respiratory gases b/w atmosphere and alveoli of lungs 2. Alveolar gas exchange: exchange of resp. gases b/w alveoli and blood 3. Gas transport: transport of resp. gases w/in blood b/w lungs and systemic cells of body 4. Systemic gas exchange: exchange of gases b/w blood and systemic cells of body

Question 35

Mechanisms of breathing

Answer 35

Several integrated aspects; - specific actions of skeletal muscles - volume changes w/in thoracic cavity - pressure changes from volume changes - pressure gradients - volumes and pressures involved in breathing