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Flashcards in deck_1284797 Deck (61):
1

Outline the key functions of the respiratory system

• Gas exchange - Serves to ensure that all tissues receive the oxygen they need and can dispose of CO2 they produce• Immune functions• Inhalation & exhalation• Vocalization • Metabolic and endocrine functions

2

Define the term upper respiratory tract

• The part of the respiratory tract above the lower border of the cricoid cartilage (which forms the lower border of the larynx) is termed upper respiratory tract.

3

Define the term lower respiratory tract

• The parts of the respiratory tract below the lower border of the cricoid cartilage, including the lungs and associated structures.

4

What are the four main structures found in the URT?

• Nose• Paranasal sinuses• Pharynx • Larynx

5

Describe the pulmonary circulatory system of the lungs

Low resistance system which is 'supply driven' rather than demand ledLow pressureeceives entire cardiac output

6

What is the purpose of resistance vessels in the pulmonary circulation?

• Do not influence total flow through pulmonary circulation, only distribution of blood within it

7

Why is tissue fluid not normally formed in the lungs?

Capillary pressure in the normal pulmonary circulation is always less than the colloid osmotic pressure

8

Give three main functions of the URT

• Conducting air from atmosphere to the lower respiratory tract• Conditioning (warming, humidification and trapping of particles) of inspired air• Protection of the airway during swallowing (larynx)

9

Give three minor functions of the URT

• Swallowing (oropharynx and laryngopharynx)• Smell (olfactory epithelium in nose)Speech (larynx)

10

What two main parts make up the nose?

• The external nose (bone and cartilage) • the nasal cavity

11

Describe the structure of the nasal cavity

• Divided into right and left cavities by the median nasal septum• Each nasal cavity extends from the nostril (anterior nares) the posterior nare (or posterior chonae) behind.

12

Outline the structure of the lateral wall of each nasal cavity

Contains three bony projections known as the choncae (superior, middle and inferior)• The space below each conchae is known as the meatus (superior, middle and inferior)

13

What structures drain into the meatus of the nasal cavity?

The paranasal sinusThe nasolacrimal duct

14

What does the floor of the nasal cavity form?

• The roof of the mouth

15

What are the three main functions of the nose?

• Respiration ○ Filters air ○ Humidifies and warms air• Organ of smell• Receives local secretion ○ Sinuses ○ Nasolacrimal duct

16

How does the structure of the nose relate to its function?

- Turbinates aid in warming and humidification by increasing SA and slowing airflow• Lined by coarse hairs which aid in filtering of inhaled air• Moist epithelium traps particles• Watery nasal secretions evaporate and humidify air

17

Aside from humidification of air, what is the function of secreted nasal mucus and associated cilia?

Mucus secreted by goblet cells traps almost all particles. Cilia waft mucus to oropharynx where it is swallowed

18

Name the four paranasal sinuses

The frontal, ethmoidal, maxillary and sphenoidal sinuses

19

Give five possible functions of paranasal sinuses

• Extension of nasal cavity (humidification and warming of inspired air)• Secrete mucus to moisten nasal chambers• Lighten weight of skull• Buffer for trauma (crumple zones)• Insulating sensitive structures from temperature variation (eye, dental roots)

20

What are the three parts of pharynx?

• Nasopharynx• Oropharynx• Laryngopharynx

21

What is the key function of the pharynx?

• Prevent aspiration of food during swallowing, which can lead to life threatening airway obstruction or infection

22

How is the nasopharynx connected to the middle ear cavity?

• By the auditory tube (eustachian tube)

23

What does the connection of the nasopharynx to the middle ear cavity allow?

• Air pressure in middle ear cavity to be equalized to atmospheric pressure

24

What issue can the connection of the nasopharynx to the middle ear cavity cause?

• URTI can be spread to the middle ear cavity via the auditory tube, resulting in middle ear infection. More likely in children than adults.

25

Outline the gross structure of the larynx

• Cartaliginous skeleton made up of 3 unpaired cartilages - epiglottis, thyroid cartilage and cricoid cartilages - and 1 set of paired cartilages, called the arytenoid cartilages• The vocal cords and the gap between vocal cords - together called the glottis

26

Give 2 main respiratory functions of the larynx

• Open during respiration, closed during swallowing - guards the entrance to the trachea• Ability to close allows cough reflex to occur

27

How can diseases of the larynx present as respiratory disease?

• Laryngeal disease presents as airway obstruction & difficulty breathing• Voice change can be first sign of serious intrathoracic disease, due to involvement of left recurrent laryngeal nerve

28

What is the path of the right and left pharyngeal nerve?

• Right - curves under subclavian artery• On left - curves under aortic arch

29

Outline the movements of the vocal cords

• Adduction (closing) occurs during swallowing • Abduction (opening) occurs during inspiration/deep inspiration• Partially open during speech (phonation)• Adducted during initial part of cough reflex

30

What are the vocal cords moved by?

• Intrinsic laryngeal muscles

31

What nerve are the intrinsic laryngeal muscles supplied by and why can this cause problems?

• The recurrent laryngeal nerve• Intra thoracic disease compressing/infiltrating the nerve can result in a hoarse voice, due to paralysis of left vocal cord

32

Aside from closure of vocal cords, outline another mechanism by which aspiration is prevented

• Epiglottis folds downwards and covers laryngeal inlet

33

What lines the pleural sac of the lungs?

• A serous membrane

34

What lines the conducting portions of the respiratory tract?

• A mucous membrane

35

What structures make up the conducting portion of the respiratory system?

Nasal cavityPharynxLarynxTracheaPrimary bronchiSecondary bronchiBronchiolesTerminal bronchioles

36

What structures make up the respiratory portion of the respiratory system?

Respiratory bronchiolesAlveolar ductsAlveoli

37

What happens to the walls of the passageways as you move down the respiratory tract?

They become thinner as lumens decrease in diameter

38

What epithelial cells are present in the conducting portion of the respiratory tract, except for the terminal bronchioles?

Pseudostratified epithelium with cilia and goblet cells

39

What cells are present in terminal bronchioles?

Simple columnar epithelium with cilia and Clara cells (release surfactant rather than mucus) - no goblet cells

40

What epithelial cells are found in the upper portion of the respiratory portion of the respiratory tract (not alveoli)

Simple cuboidal epithelium with Clara cells and sparsely scattered cillia

41

What cells are found in alveoli?

Simple squamous and cuboidal cells (secrete surfactant)

42

Which parts of the conducting system are extrapulmonary?

Nasal cavityPharynxLarynxTracheaPrimary bronchi

43

What is the function of venous plexuses in the non-olfactory regions of the nasal cavity?

Swell every at different point every 20-30 minutes and prevent over drying by varying airflow

44

How does the olfactory region of the nasal cavities differ from the non-olfactory?

No mucus secreting cellsContain olfactory cells (bipolar neurons)

45

What are Clara cells?

• Dome shaped cells• Produce lung surfactant• Produce Clara cell protein ○ Measurable marker in bronchoalveolar lavage fluid (lowered then lung damage) ○ Measurable marker in serum (if raised, leakage across air-blood barrier)

46

What are the vocal cords lined with?

• Stratified squamous epithelium

47

Describe the histology of trachea and primary bronchi

- Contain cartilage rings and spiral muscle- Lined with pseudo stratified cilliated columnar epithielium and various glands

48

Why are objects more like to lodge in right bronchus than left?

• More vertical than left

49

What is the function of the secretions from the epithelial and submucosal glands of the trachea and bronchi?

• Anti-bacterial function, contains lysozymes and anti-proteases

50

Describe the wall of the trachea

• Epithelial layer• Lamina propria, rich in immune cells• Sub mucosa• Cartilage ring

51

What are the main components of the LRT (in order)

Trachea• Main bronchi (3 on right, 2 on left)• Lobar bronchi• Segmental bronchi• Sub-segmental bronchi• Bronchioles • Alveoli• Pulmonary and bronchial circulatory system

52

What is each terminal bronchiole connected to?

• Set of respiratory bronchioles • Alveolar ducts• Alveoli

53

How does a bronchiole differ from a bronchi?

• Bronchiole has less cartilage and no glands • Bronchioles have more smooth muscle• Bronchioles kept open by surrounding alveoli• 1mm or less in diameter

54

Why is absence of cartilage in bronchioles an issue?

• Allows air passages to constrict and almost close down when smooth muscle contraction excessive

55

What is a terminal bronchiole?

• Smallest airways of the conducting portion• Absence of goblet cells is important to stop individuals drowning in their own mucus

56

What is an alveolar duct?

An opening to alveolar sacs lined with alveoli

57

What is an alveolus?

• Plural of alveoli

58

What can an alveoli open into?

A respiratory bronchiole An alveolar duct An alveolar sac Another alveolus

59

Describe the structure of alveolar walls

• have abundant capillaries • are supported by a basketwork of elastic and reticular fibres. • have a covering composed chiefly of type I pneumocytes. • have a scattering of intervening type II pneumocytes.

60

How close are alveoli to capillaries?

• 0.2 micrometres

61

What cell types make up alveoli?

• 90% simple squamous• 10% cuboidal• Macrophages