Respiratory anatomy

Question 1

Respiratory system consists of 3 components, what are they?

Answer 1

Respiratory controller e.g., CNS, Ventilator pump e.g., chest muscles, Gas exchangers e.g., alveoli

Question 2

Name all main components of the upper airways

Answer 2

Mouth, nose Pharynx (nasopharynx, oropharynx, laryngopharynx)

Question 3

What is the epiglottis and it’s function?

Answer 3

A flexible flap, protecting the glottis, prevents food from entering the lungs which could rot and cause inflammation/infection
Supported by thyroid cartilage

Question 4

Mechanism of epiglottis

Answer 4

during swallowing larynx moves up and pushes epiglottis causing it to fold open

Question 5

Main function of upper airways

Answer 5

conducts airs, primary defense (prevents bacteria from entering lungs), warms air, prevents choking

Question 6

Name the main component of the lower respiratory tract

Answer 6

Larynx (voicebox), trachea, bronchi, lungs

Question 7

Function and location of turbinate bones

Answer 7

found at the back of the nasal cavity,
Role: mixes and swirls incoming air from nose passage, warms it to prevent damage to lungs

Question 8

Name difference’s between Left and Right Lung

Answer 8

Left: is taller and narrower, due to making space for the heart, it has 2 lobes so 2 secondary bronchi and one oblique fissure dividing the 2 lobes and is 10% smaller than the right
Right: is wider and shorter, larger than the left lung, and consists of 3 lobes so has 3 secondary bronchi which is divided by 2 oblique fissures. It is shorter in order to make space for the liver on the RHS

Question 9

Mechanism of respiratory Cilia

Answer 9

1. cilia line the airways e.g., trachea
2. cilia move in a synchronized rhythm to waft mucus toward the oropharynx and propel particles
3. cilia in the nasopharynx waft downwards
4. cilia in larynx waft upwards
5. once mucus reaches the larynx it stimulates receptors which bring on a cough reflex
6. mucus is then swallowed or spat out

Question 10

State the order of organization of the lungs

Answer 10

Trachea, primary bronchi, secondary bronchi, tertiary bronchi, terminal bronchioles, respiratory bronchioles, alveolar ducts, alveoli sacs

Question 11

Definition of dichotomous branching:

Answer 11

Where each time a branch will divide into 2 further branches

Question 12

Structure & function of the Larynx

Answer 12

The larynx is made up of cartilage and bone, which is held together by ligaments and membranes
Known as the voicebox, cartilage froms a framework to support vocal cords,

Question 13

Structure of the Trachea

Answer 13

The trachea runs down the base of the larynx and has a diameter of 2cm
C-shaped rings of cartilage support the trachea. These incomplete rings prevent obstruction to the esophagus during swallowing. The cartilage is needed to support the lungs during pressure changes that occur. As you go further down the lungs less cartilage is found as less support is required

Question 14

What is the top of the lungs called?

Answer 14

The apex

Question 15

Describe the function of the Hilum

Answer 15

Hilum is responsible for securing the lungs in place, and connecting all major blood vessels. It is found at the root of the lungs

Question 16

Describe how the lungs are protected in the chest cavity

Answer 16

The lungs are enclosed within the ribcage, protecting them from physical damage as it acts as a barrier.
The lungs are enclosed in a double membrane: the visceral membrane (around the lungs) and the parietal membrane (found around the ribs)
The lungs also contain pleural fluid which lubricates them , preventing them from drying out, sticking together, and reducing surface tension between the lungs. The fluid also prevents collapse of the lungs

Question 17

Segments in the lungs

Answer 17

The right lung has 10 segments and the left has 8-9 segments (depends on the person)
These segments divide into lobules which are separated by a interlobular septum made of connective tissue

Question 18

Structure of lobules

Answer 18

Each lobule has 10-30 acini
Lobules consist of terminal bronchioles, respiratory bronchioles and alveolar ducts

Question 19

What is an acini (lungs)

Answer 19

A functional unit of the lungs, roughly 7.5-8.5mm in diameter, Acini means cluster of cells

Question 20

How many alveoli approximately does one human have?

Answer 20

480 million, provides SA of 80m2

Question 21

Why is important to have so many alveoli

Answer 21

Having lots of alveoli provides a large surface area in which diffusion can occur at a greater rate, alveoli also have a complex network of capillaries surrounding them. This creates and maintains a steep concentration gradient between oxygen and carbon dioxide

Question 22

Describe structure of Airway cells

Answer 22

Ciliated Pseudostratified columnar epithelium, has mucus glands as well as goblet cells to secrete mucus, macrophages to engulf bacteria, simple cuboidal epithelium and simple squamous epithelium

Question 23

Name 3 types of epithelium found in the lungs

Answer 23

1. pseudostratified ciliated columnar epithelium
2. simple squamous epithelium
3. cuboidal epithelium

Question 24

What is the function of Alveolar macrophages?

Answer 24

To patrol the lungs and engulf any foreign bacteria, break it down (phagocytosis) and keep the environment sterile

Question 25

How many types of epithelium in the ALVEOLI?

Answer 25

2 types

Question 26

Describe type 1 epithelium in the ALVEOLI?

Answer 26

Type 1 is thin (simple squamous) to provide a short diffusion distance, and takes up 90-95% of alveoli. The thinness allows RBC’s to pass close by and take up O2 from alveoli

Question 27

Describe type 2 epithelium in the ALVEOLI?

Answer 27

Type 2 produces lung surfactant, which makes up 60% of alveolar cells, only takes up 5% of the SA

Question 28

What is the importance of lung surfactant?

Answer 28

to increase pulmonary compliance, prevent collapse of alveoli by preventing them from sticking together during expiration, prevents the lungs from collapsing and reducing surface tension

Question 29

Name the 2 types of circulation in the LUNGS

Answer 29

pulmonary circulation and bronchial circulation

Question 30

Describe Pulmonary circulation

Answer 30

Deoxygenated blood is received from the RHS of the heart through the pulmonary trunk which divides into pulmonary arteries, blood in the arteries passes by alveoli oxygen diffuses in and CO2 diffuses out, oxygenated blood then returns to the heart via the pulmonary veins to be pumped into systemic circulation

Question 31

Describe Bronchial circulation

Answer 31

This type of circulation supplies the lung tissue itself with oxygenated blood. Oxygenated blood is received from the thoracic aorta and enters the Hilum

Question 32

Describe the primary defense of the lungs

Answer 32

1. contains goblets cells which secrete mucus to trap bacteria from entering the lungs where infection/ inflammation could occur
   2, Cilia waft mucus-containing bacteria to the back of the throat to be swallowed or coughed up by stimulating receptors
2. Bacteria is coughed up via cough reflex
3. Having an intact epithelium provides a physical barrier

Question 33

Describe the secondary defenses of the lungs

Answer 33

Secondary defenses include WBCs such as neutrophils and macrophages
Macrophages are involved with the engulfing and breakdown of bacteria. When bacteria is present they release chemicals alerting macrophages of their presence.
Neutrophils attack and kill bacteria

Question 34

Function of the nasopharynx

Answer 34

Connects the nasal cavity to the respiratory system allowing air to get from the nose to the lungs, it filters incoming air & humidifies it

connects to middle ear, involved in balancing air inside & outside the cell, maintaining pressure

Question 35

Function of the pharynx

Answer 35

acts as a passage for food & drink, moistens air & contains lymphoid tissue involved in immune response

Question 36

Ease of breathing requires….

Answer 36

Compliance, elasticity & airway resistance
Elasticity-lungs can expand & return to normal size due to connective tissue, loss if connective tissue results in disease e.g., emphysema, loss of elasticity results in forced ventilation putting more strain on the lungs

Compliance (stretch)- the effort provided by alveoli, healthy lung is compliant, compliancy reduced when lung surfactant is insufficient

Airway resistance- more resistance requires more effort to ventilate, increased mucus can narrow airway, obstruction (physiological/physical) can increase resistance e.g., oedema, cystic fibrosis forced ventilation uses accessory muscles, e.g., scalene

Question 37

At what age do humans have the highest respiratory rate?

Answer 37

As infants the RR is between 30-55 breaths per minute compared to adults of 12-20 bpm