ANA 204 Respiratory system

Question 1

The respiratory system is made up of what?

Answer 1

Nasal cavities
Nasopharynx
Larynx
Trachea
Brochii
Bronchioles

Question 2

What is the last conducting part of the repiratory system

Answer 2

Bronchioles

Question 3

Describe the structure of the nasal cavities

Answer 3

1. Beginning of the respiratory system
2. Paired chambers separated by a septum
3. Extends from the nostrils to the posterior nasal aperture
4. A hollow organ made up of bone, cartilage and connective tissue covered by a mucosa membrane

Question 4

What is the respiratory system?

Answer 4

The respiratory system includes the lungs and a branching system of tubes that link the sites of gas exchange with the external environment.

Question 5

Regions of under the nasal cavity, pharynx and larynx

Answer 5

Nasal Cavity
1.Vestibule
2.Olfactory region
3.Respiratory region

Pharynx
1.Nasopharynx

Larynx
1.Epiglottis: elastic cartilage
2.Vocal cords: striated skeletal muscle / elastic fibres

Question 6

What constitutes the upper respiratory tract?

Answer 6

The upper respiratory tract includes the nasal cavity, paranasal sinuses, pharynx and the portion of the larynx above the vocal cords.
Lined by stratified squamous and ciliated pseudostratified columnar epithelia

Question 7

what constitutes the lower respiratory tract

Answer 7

The lower respiratory tract includes the larynx below the vocal cords, the trachea, bronchi, bronchioles and the lungs.
Lined by respiratory epithelium

Question 8

What are the 2 functional and histological divisions of the respiratory system?

Answer 8

Conducting portion and respiratory portion

Question 9

Describe the conducting portion

Answer 9

a conducting portion, which consists of all the components that conditioned air and bring it into the lungs ( nasal cavities, nasopharynx, larynx, trachea, bronchi, bronchioles and terminal bronchioles)

Function
* To provide a conduit through which air can travel to and from the lungs and to condition the inspired air.
* To ensure an uninterrupted supply of air

Question 10

Describe the respiratory portion

Answer 10

a respiratory portion, where gas exchange actually occurs, consisting of respiratory bronchioles, alveolar ducts, and alveoli in the lungs.
NOTE: Alveoli are saclike structures that make up the greater part of the lungs.
* They are the main sites for the principal function of the lungs—the exchange of O2 and CO2 between inspired air and blood

Question 11

Constituents of the trachea bronchi, bronchioles

Answer 11

Trachea: C-shaped cartilage with smooth muscle

Bronchi
Extrapulmonary/primary bronchi: begin at the bifurcation of the trachea and lead to lungs: extensions of the trachea
Intrapulmonary/secondary and tertiary bronchi: begin at lung hilum. Smooth muscle and hyaline cartilage plates

Bronchioles: no cartilage and Clara cells
Terminal bronchioles: increased Clara cells

Question 12

Describe the vestibule of the nasal pharynx

Answer 12

A dilated anterior portion of the nasal cavity
Lined with skin and has short, stiff hairs named vibrissae that prevent large dust particles to enter
Dermis houses numerous sebaceous glands, lined by keratinized stratified squamous epithelium
Within the vestibule, the epithelium loses its keratinized nature and undergoes a transition into typical respiratory epithelium before entering the nasal fossae

Question 13

Cells respiratory epithelium

Answer 13

1. Ciliated columnar cells
2. Goblet cells
3. Brush cells
4. Small granule cells
5. Basal cells

Question 14

Describe the nasal fossae

Answer 14

Nasal Fossae
* The nasal cavities lie within the skull as two cavernous chambers separated by the osseous nasal septum.
* Extending from each lateral wall are three bony shelflike projections called conchae.
* The middle and inferior conchae are covered with respiratory epithelium while the superior conchae are covered with a specialized olfactory epithelium
The narrow passages between the conchae improve the conditioning of the inspired air by increasing the surface area of moist, warm respiratory epithelium and by slowing and increasing turbulence in the airflow.

Question 15

Function of goblet cells

Answer 15

. Goblet cells are the next most abundant in some areas of the respiratory epithelium (also known as MGC).
* The apical portion of these cells contains the mucous droplets composed of glycoproteins, they produce mucus

Question 16

Function of basal cells

Answer 16

Basal cells (Short) are small rounded cells on the basement membrane and not extending to the luminal surface.
* These cells are believed to be generative stem cells that undergo mitosis and subsequently differentiate
into the other cell types.
Forms an incomplete layer of cells

Question 17

Function of olfactory cells

Answer 17

Olfactory cells
* are bipolar nerve cells characterized by a bulbous apical projection (olfactory vesicle) from which several modified cilia extend.
* (1) Olfactory cilia (olfactory hairs)
* (a) are very long, nonmotile cilia extending over the olfactory epithelium’s surface.
* (b) act as receptors for odour

Question 18

Describe the nasopharynx

Answer 18

• It is lined by respiratory epithelium, whereas the oropharynx and laryngopharynx are lined by stratified
  squamous nonkeratinized epithelium.
• The lamina propria of the nasopharynx, located beneath the
  respiratory epithelium,
• contains mucous and serous glands as well as an abundance of lymphoid tissue

Question 19

Describe the epiglottis

Answer 19

Central core of elastic cartilage
It extends into the pharynx and has lingual and laryngeal surfaces.
* The entire lingual surface and the apical portion of the laryngeal surface are covered with stratified squamous keratinized epithelium.
* At variable points on the laryngeal surface of the epiglottis the
epithelium undergoes a transition to ciliated pseudostratified columnar epithelium.
* Mixed mucous and serous glands are found in the lamina propria beneath the epithelium

Question 20

Describe the larynx

Answer 20

• a. The larynx connects the pharynx with the trachea.
  Lined by respiratory epithelium
• b. The wall of the larynx is supported by hyaline cartilages (thyroid.up, cricoid.up, and lower part of arytenoids.p) and elastic cartilages (epiglottis.up, corniculate.p and tips of arytenoids/cuneiform.p).
• c. The wall also possesses skeletal muscle, connective tissue, and glands.
• 2. The vocal cords consist of skeletal muscle (the vocalis muscle, makes up the core of the true vocal cord, controlling phonation), the vocal ligament (formed by a band of elastic fibres) and a covering of stratified squamous nonkeratinized epithelium.
• a. Contraction of the laryngeal muscles changes the size of the opening between the vocal cords, which affects the pitch of the sounds caused by air passing through the larynx
  Closes off the airway during swallowing
  Has two folds:
  Superior vestibular folds (false vocal fold) lined by respiratory epithelium
  Inferior vocal folds (true vocal fold) lined by stratified squamous nonkeratinized epi.

Question 21

Describe the trachea

Answer 21

1. Lower border of cricoid cartilage (C6) to its level of birufication (T4) into right and left bronchi
2. Fibroelastic cartilaginous tube with 4 layers that is completed posteriorly by smooth trachealis muscle.
3. Throughout its length, the lumen is lined by pseudostratified ciliated columnar epithelium with goblet cells (respiratory epithelium).
4. consists of c shaped cartoilaginous bands

Question 22

Describe the respiratory mucosa of the nasal cavity

Answer 22

It is lined by pseudostratified columnar epithelium
Made up of:
epithelium
lamina propria (secretes mucous and serous components)
nasal glands
blood vessels
Goblet cells, brush cells, small granular cells,ciliated cells, basal cells

Question 23

Describe the olfactory musoca of the nasal cavity

Answer 23

Lined by pseudostratified ciliated columnar cells with olfactory, sustentacular, brush cells, olfactory neurons and basal cells
It is lined with olfactory receptors for smell
Made up of:
Epithelium
Lamina propria: large serous glnads involved in protection against odour
Olfactory glands
Blood vessels

Question 24

Functions of the olfactory mucosa cell types

Answer 24

sustentacular: form the superficial layer, columnar, maintain microenvironment for smell and metabolic support
Basal cells: form deepest layer of epithelium, stem cells/ progenitor cells
Olfactory neurons: bipolar and distinguished from supporting cells by the position of their nuclei

Question 25

Describe the layers of the trachea

Answer 25

Mucosa: Lined with respiratory epithelium, thick basement membrance and lamina propria
Submucosa: C–shaped rings of hyaline cartilagethe keeps the trachea open
Adventitia: contains CT that adheres the trachea to adjacent structures

Trachealis muscle: a bundle of smooth muscle that bridges the gap of the c-shaped cartilages (surrounded by adventitia)

Question 26

Describe the bronchi

Answer 26

trachea bifurcates at the level of T4 into L and R principal bronchi
similar the trachea
encircled by a cartilaginous ring

Question 27

Describe bronchioles

Answer 27

lined by ciliated pseudostratified epithelium to simple columnar to simple cuboidal
smooth muscle wall
lack of cartilage
club/clara cells: dome-shaped apical cells secrete glycosaminoglycans which help protect the bronchiole lining

Question 28

Difference between terminal and respiratory bronchiole

Answer 28

Neither have cartilgae
both contain smooth muscle

Respiratory bronchiole contins alveoli in its wasll and therefore is the first structure to participate in gaseous exhange in the lung

Question 29

Describe alveolar wall

Answer 29

thin
lined with sse resting on a basement membrane
alveoli increase SA

Question 30

Describe the types of alveolar cells

Answer 30

Type 1 pneumocytes: lines 95% of alveolar surface, flattened, cells joined by tight junctions, predominant cells carrying out gas exchange
Type 2 pneumocytes: act as stem cells and secretes surfactant
Type 3: brush cells
Alveolar macrophages/ dust cells: swallow dust particles

Question 31

Describe asthma

Answer 31

Asthma is a chronic inflammatory disorder of the airways, characterised by hypersensitivity, reversible outflow obstruction and bronchospasm.

There is remodelling of the small airways, causing increased smooth muscle thickness around the bronchioles, damaged epithelium and a thickened basement membrane.

“Asthma attacks” are acute exacerbations of the condition whereby a trigger (e.g. allergens, exercise) causes sudden inflammation and contraction of the smooth muscle around bronchioles (bronchospasm). This narrows the airways, causing difficulty in breathing and wheezing, a characteristic feature of asthma