Respiratory Anatomy

Question 1

External respiration

Answer 1

Oxygen is absorbed from atmosphere into blood within pulmonary capillaries
Carbon dioxide secreted

Question 2

Internal respiration

Answer 2

Exchange of gases between blood in systemic capillaries

Question 3

Cellular respiration

Answer 3

Individual cells gain energy by breaking down molecules in mitochondria, consuming oxygen and generating carbon dioxide

Question 4

Pulmonary ventilation

Answer 4

Bulk movement of air into and out of lungs

Question 5

Ventilatory pump

Answer 5

Rib cage + associated muscles + diaphragm

Question 6

Conducting part of respiratory system

Answer 6

Series of cavities and thick walled tubes which conduct air between the nose and the lungs
Nasal cavities + Pharynx + Larynx + Trachea + Bronchi + Bronchioles

Question 7

Respiratory part of respiratory system

Answer 7

Tiny thin walled airways where gases are exchanged between air and blood
Respiratory bronchioles + Alveolar ducts + Alveolar sacs + Alveoli

Question 8

Gas exchange location

Answer 8

Respiratory part of the respiratory system

Question 9

Surface area of alveoli

Answer 9

75m2 (3/4 tennis court)

Question 10

Upper respiratory tract

Answer 10

Nasal cavity to larynx

Question 11

Lower respiratory tract

Answer 11

Trachea to bronchus to bronchioles to alveoli

Question 12

Filtration location

Answer 12

Vibrissae (nasal hairs)

Mucociliary escalator

Question 13

Warming location

Answer 13

Capillary network in nasal cavity underneath epithelium

Question 14

Humidifying location

Answer 14

Nasal cavity covered in mucus membrane

Question 15

Conchae

Answer 15

Bony projections that increase surface area of the mucus membrane in the nasal cavity and mix and slow down inhaled air

Question 16

Air pathway from nose to trachea

Answer 16

Nose to nasopharynx
Nasopharynx to oropharynx
Oropharynx to laryngopharynx
Laryngopharynx to glottis
Glottis to trachae

Question 17

Food pathway from mouth to oesophagus

Answer 17

Mouth to soft palate
Soft palate closes nasopharynx
Soft palate to oropharynx
Oropharynx to laryngopharynx
Epiglottis closes glottis
Oesophagus forced open
Laryngopharynx to oesophagus

Question 18

Number of respiratory generations

Answer 18

28

Question 19

Conducting zone structures

Answer 19

Trachea
Main stem bronchi
Lobar bronchi
Segmental bronchi
Smaller bronchi
Bronchioles
Terminal bronchioles

Question 20

Respiratory zone structures

Answer 20

Respiratory bronchioles
Alveolar ducts
Alveolar sacs

Question 21

Lobes in lobar bronchi

Answer 21

3 lobes on the right

2 lobes on the left

Question 22

Describe the trachea

Answer 22

12cm long tube as thick as a thumb
Supported by incomplete C shaped rings of cartilage
Free ends of cartilage connected by smooth trachealis muscle
Lined with ciliated pseudostratified columnar epithelium
Cilia transport mucus sheet up towards nasopharynx
Anterior to oesophagus

Question 23

Describe the bronchus wall

Answer 23

Pseudostratified ciliated columnar epithelium and goblet cells lined with mucus
Smooth muscle
Mucus glands
Cartilage plates
Alveolus

Question 24

2 sources of mucus

Answer 24

Goblet cells and mucus glands

Question 25

Describe the bronchiole wall

Answer 25

Simple ciliated columnar epithelium and club cells lined with watery secretion
Smooth muscle
Alveolus

Question 26

Role of smooth muscle

Answer 26

Controls air flow by constriction and relaxation

Question 27

Pathological cause of asthma

Answer 27

Over-constriction of smooth muscle in the bronchi and bronchioles restricting air flow and requiring bronchodilators to relax

Question 28

Role of cartilage plates

Answer 28

Keep bronchi open - cartilage plates are not prone to collapse
Bronchi more rigid than bronchioles because of presence of cartilage plates

Question 29

Club cells

Answer 29

Found between epithelial cells in bronchiole walls and secrete a non-mucus watery secretion to keep cells hydrated and air moist

Question 30

Goblet cells

Answer 30

Found between epithelial cells in bronchus walls and secrete mucus

Question 31

Cells in alveolar walls

Answer 31

Red blood cells (in pulmonary capillary)
Endothelial cells (in pulmonary capillary)
Squamous pneumocytes (type I cells)
Alveolar macrophages
Surfactant cells (type II cells)

Question 32

Role of surfactant

Answer 32

Liquid lining reduces the work of breathing by reducing surface tension in alveoli and stopping alveoli completely collapsing

Question 33

Role of surfactant cells

Answer 33

To secrete surfactant

Question 34

Role of squamous pneumocytes

Answer 34

Very thin trails of cytoplasm in each cell surrounding an area of an alveoli which minimises diffusion distance for gas exchange

Question 35

Role of alveolar macrophages

Answer 35

Act as normal macrophages to engulf pathogens and foreign particles
Last line of defence if air is contaminated

Question 36

Describe the diffusion barrier in alveoli

Answer 36

Squamous pneumocyte adjacent to alveolar air space
Capillary endothelium adjacent to blood plasma
Basement membranes of squamous pneumocytes and capillary endothelium fused to reduce diffusion distance

Question 37

Primary bronchi

Answer 37

Right and left main stem bronchi supplying each lung

Question 38

Secondary bronchi

Answer 38

Lobar bronchi supplying lobes (3 on the right and 2 on the left)

Question 39

Tertiary bronchi

Answer 39

Segmental bronchi supplying segments of the lung (10 on the right and 8 on the left)
Each segment has its own air and blood supply

Question 40

Describe the pleurae

Answer 40

Smooth double layered membrane that covers each lung and lines the thoracic cavity
Two pleurae are continuous at the root of the lung (hilum)
Separated by thin film of fluid that allows pleurae to slide past each other without friction
Fluid also prevents complete separation of the pleurae

Question 41

Describe movement of the ribs during ventilation

Answer 41

Ribcage movement responsible for 25% air movement into and out of the lungs
Active inspiration requires contraction of external intercostal muscles which run obliquely between ribs
Passive expiration doesn’t require muscular action. The ribcage relaxes back to its resting position
During exercise, both sets of intercostal muscles become active and both inspiration and expiration require muscular action

Question 42

Describe how the ribs increase the volume of the thorax

Answer 42

Ribs pivot around their joints with the vertebral column. Contraction of the external intercostal muscles lifts the ribs and rotates them around their pivot points. The ribs lift and swing upwards and outwards, increasing the volume of the thorax and allowing air in. The internal intercostal muscles run at right angles to the external intercostal muscles and when they contract they drag the ribs downwards - only for forceful exhalation.

Question 43

Describe movement of the diaphragm during ventilation

Answer 43

Diaphragmatic muscle contracts which flattens the diaphragm and pulls the central dome down, increasing the volume of the thorax and causing inspiration. Passive relaxation of the muscle lifts the diaphragm back up towards the thorax reducing the volume and causing expiration.
Responsible for 75% of bulk flow of air during quiet breathing.

Question 44

Describe the diaphragm

Answer 44

The diaphragm is a dome shaped platform that forms the floor of the thorax and the roof of the abdomen. Its central part is a thin sheet of connective tissue (aponeurosis) called the central tendon. The lateral margins are fast acting skeletal muscle innervated by the phrenic nerve.