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Year 2: Human Anatomy and Physiology > RS: Respiratory Tract > Flashcards

Flashcards in RS: Respiratory Tract Deck (51)
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1
Q

Describe the gross anatomy of the lung

A

The lung is made of 5 lobes: 3 right and 2 left. The cardiac notch is present on the left side, to accommodate the heart. The lungs lie beneath the ribcage. The base of the lungs rests on the diaphragm and the top converges into a narrow apex under the clavicle bone.

2
Q

What is ventilation?

A

The exchange of air between the lungs and the atmosphere so that oxygen can be exchanged for carbon dioxide in the alveoli (the tiny air sacs in the lungs).

3
Q

What is gas exchange?

A

Process that occurs between the lung surface and the blood, and other tissues of the body. Exchange of carbon dioxide for oxygen.

4
Q

What is oxygen utilisation?

A

Energy liberating reactions of all cells in the body, whereby oxygen is necessary for these processes.

5
Q

What is the space between the lungs called?

A

Mediastinum

6
Q

What organs called be found in the space between the lungs (mediastinum)?

A
  1. Heart
  2. Oesophagus (wind pipe)
  3. Lower trachea
  4. Primary bronchi
7
Q

What is the pulmonary artery?

A

The pulmonary artery is an artery that arises from the pulmonary trunk and carries deoxygenated, arterial blood to the alveoli. The pulmonary artery branches multiple times as it follows the bronchi, and each branch becomes progressively smaller in diameter.

8
Q

What is the lung hilum?

A

Hila, or lung roots, are relatively complicated structures that consist mainly of the major bronchi and the pulmonary arteries and veins.

9
Q

Where are the lungs positioned?

A

In the thoracic cavity

10
Q

What is the primary function of the respiratory system?

A

Primary function is the exchange of gases including carbon dioxide and oxygen between the body and the environment.

11
Q

What are the 5 secondary functions of the respiratory system?

A
  1. Warming and humidifying incoming air- creates a moist lining to promote oxygen diffusion and matches the air with the core body temperature of 37 degrees.
  2. Keeping airway clean and sterile- filter pathogens and debris.
  3. Keeping airways open during pressure changes in breathing.
  4. Keeping alveoli open against surface tension
  5. Regulation of air-flow and blood-flow.
12
Q

What is the function of the nasal cavity and the nose?

A

Air enters the nose, and the begin of the respiratory system, through the nostrils (anterior name) and exists through the back of the nasal cavity (posterior mare). Large debris is filtered by nasal hairs.

13
Q

Describe the structure of the nasal cavity

A

The naval cavity is comprised of 3 curved turbinate bones (nasal concha bones) that churn the air as it passes to initiate particle contact with the sticky mucus lining of the nasal passage.

14
Q

What is the purpose of respiratory mucous in the nasal cavity?

A

Warms, moistens and cleans the air as it passes through the nasal cavity

15
Q

What are the 3 layers of the nasal respiratory mucosa?

A
  1. Psuedostratified ciliated columnar epithelium
  2. Goblet cells (secrete mucus that traps debris and dust)
  3. Basement membrane adhering to the thick layer of lamina propria. The lamina propria is rich with blood vessels (eradicate heat to warm the air) and seromucosal glands (secrete mucus and water mix).
16
Q

What are the 2 regions of the respiratory system?

A
  1. Upper respiratory tract

2. Lower respiratory tract

17
Q

What 3 major organs make up the upper respiratory tract?

A
  1. Nose
  2. Pharynx
  3. Larynx
18
Q

What 3 major organs make up the lower respiratory tract?

A
  1. Trachea
  2. Bronchus
  3. Bronchioles (primary, secondary and tertiary)
19
Q

Where does the respiratory mucosa line?

A

The turbinate bones

20
Q

What is the function of the enzymes (lysozyme) in the respiratory mucosa?

A

Microbial protection; break down bacterial cell wall of invading pathogen

21
Q

What is the function of the cilia in the respiratory mucosa?

A

Wave-like cilia on the epithelial surface of the respiratory mucosa help to move trapped particles to the back of the throat where they are normally swallowed and destroyed by the stomach acid. Inhaled particles are normally trapped by mucous, produced by goblet cells, which is then swallowed and destroyed.

22
Q

What is the larynx (voice box)?

A

The larynx is a 1-2 inch tube of interconnecting cartilage, ligaments and muscle that guards the lower respiratory tract during swallowing (deglutition).

23
Q

What is the function of the larynx?

A

Prevents food entering the trachea when swallowing by moving upwards and pushing against the epiglottis to close the lower respiratory tract.

24
Q

What is the pharynx (throat)

A

The pharynx is a 4-5 inch fibre-muscular tube that conducts air from the nasal cavity to the larynx.

25
Q

What region of the pharynx comes into contact with the air and is closed off from the rest of the pharynx to prevent entry into the digestive system?

A

Nasopharynx

26
Q

What is the epithelial lining of the nasopharynx?

A

Psuedostratified ciliated columnar epithelium, similar to that found in the nasal cavity

27
Q

What is the epithelial lining in the oropharynx and laryngopharynx?

A

Stratified squamous epithelium which is non-keratinised to provide a moist layers that protects against abrasion.

28
Q

What is the trachea?

A

The trachea is a 4-5 inch tube that conducts air between the larynx and the primary bronchi.

29
Q

How is the trachea structurally supported to prevent collapse?

A

C-shaped hyaline cartilage rings which prevent the trachea from collapsing

30
Q

What are the 4 distinct layers of the trachea?

A
  1. Respiratory mucosa in the luminal air surface
  2. Submucosa- connective tissues, blood vessels, glands and nerves.
  3. Cartilage ring- connected by smooth muscle to allow for control of the lumen size during breathing; muscles contract to help force air out.
  4. Adventitia- a band of loose connective tissue that keeps the trachea in place within the chest wall.
31
Q

How is the trachea lumen size controlled and why is this needed?

A

Contraction of cartilage rings, connected by smooth muscle, allows for the control and regulation of the lumen size. Muscle contraction helps to force air out. This control aids in ventilation and the movement of gases into and out of the body.

32
Q

What is the function of the bronchi?

A

Conduct air from the trachea through primary, secondary and tertiary bronchi into the bronchioles.

33
Q

Describe the structure of the bronchi

A

The bronchi walls appear similar to the trachea walls except the goblet cells are less numerous and secrete less mucous, and there are broken rings of smoooth muscles fibres that constrict during exhalation. The plates of hyaline cartilage are also thinner and less numerous in the secondary and tertiary bronchi.

34
Q

How many primary bronchi are there?

A

2

35
Q

How many secondary bronchi are there?

A

5 in each lung

36
Q

How many tertiary bronchi are there?

A

18 (10 right and 8 left)

37
Q

What is the function of the bronchioles?

A

Conduct air between the tertiary bronchi and the alveoli.

38
Q

How are the bronchioles and alveoli connected?

A

Bronchioles are attached to alveoli surrounded by elastic fibre which holds the bronchiole open during breathing movements and provides elastic recoil.

39
Q

Describe the epithelial transition from the large bronchioles to the smaller bronchioles closer to the alveoli

A

The bronchiole walls transition from ciliated simple columnar epithelium in the large bronchioles to ciliated simple cuboidal epithelium in the small bronchioles, further into the lungs.

40
Q

Describe the structure of the bronchioles

A

Goblet cells and seromucosa glands become less and less with each bronchiole division and cartilage is absent. There is a ring of smooth muscle fibres which contract during exhalation and the resultant compression causes characteristic folds of bronchiolar epithelium.

41
Q

How big are alveoli?

A

0.2-0.5mm in diameter

42
Q

What is a cluster of alveoli called?

A

Alveoli sac

43
Q

How are the alveoli supported to facilitate efficient gas exchange?

A

A network of capillaries and supportive collagen and elastic fibres are found in the narrow intestinal space that separates the alveoli, to aid in efficient gas exchange between the lungs and the blood.

44
Q

How does gas exchange take place between the alveoli and the blood?

A

Gases diffuse across the small diffusion pathway between the alveoli epithelium and the blood capillary network that intertwines with the bundles of alveoli.

45
Q

What are the alveoli cells called?

A

Pneumocytes

46
Q

What are the 2 types of alveoli cells (pneumocytes)?

A
  1. Type I (roughly 95%): simple squamous cells that are the main site of gas exchange.
  2. Type II (roughly 5%): cuboidal cells with microvilli that secrete surfactant
47
Q

What is surfactant?

A

Surfactant is a complex of phospholipids and proteins that reduce surface tension, by interspersing with water molecules, to prevent alveolar collapse.

48
Q

What is the function of alveolar macrophages?

A

Alveolar macrophages (phagocytes) move between alveoli and engulf exhaled dust particles and debris.

49
Q

What are alveolar pores?

A

Alveolar pores perpetrate the alveolar wall to allow air to pass between the alveoli and provide an alternate route for air if an obstruction occurs or some alveoli collapse; this allows for gas to equilibrate for maximal gas exchange.

50
Q

What is the width of the respiratory membrane and why is this important for gas exchange?

A

Roughly 0.5mm in width; minimal to help maximise gas exchange as creates a small diffusion pathway.

51
Q

How does the build up of fluid in the lungs inhibit efficient gas exchange?

A

Inhibits efficient gas exchange by increasing the diffusion pathway