Cardiorespiratory Anatomy, Physiology and Breathing

Question 1

What are the functions of and structures in the upper respiratory tract?

Answer 1

FUNCTION: warming, humidifying and filtering air.
STRUCTURES: nasal cavity (nasal hairs responsible for filtering), pharynx and larynx.

Question 2

What are the two parts of the lower respiratory tract?

Answer 2

This is split into the conducting and gaseous exchange parts.
- CONDUCTING: related to secretion impairments
- GASESOUS: related to gaseous exchange impairments

Question 3

What is the function of the conducting part of the LRT?

Answer 3

To conduct air into gaseous exchange part of the lungs & trap particles 1-5 micrometres via sedimentation in the mucous layer in airways. Particles are moved via MCC to the pharynx for swallowing.

Question 4

What are the structures in the conducting part of the LRT?

Answer 4

Consists of trachea, bronchi, bronchioles & terminal bronchioles. Has two parts:
- CENTRAL AIRWAYS: >2mm diameter, has mucous layer, ciliated epithelium, goblet cells, and submucosal glands
- PERIPHERAL AIRWAYS: <2mm diameter, no mucous layer, less & smaller cilia, & Clara cells present

Question 5

What is the function of the gaseous part of the LRT?

Answer 5

To support gas exchange btw CO2 and O2 occurring via diffusion in the alveoli that is both ventilated and perfused.

Question 6

What are the structures in the gaseous part of the LRT?

Answer 6

Consists of the respiratory bronchioles, the alveolar ducts and the alveolar sacs (surface area for gas exchange, approx. 150cm2).

Question 7

What is diffusion?

Answer 7

The movement of gases btw the alveoli, plasma and RBC.

Question 8

What is perfusion?

Answer 8

Perfusion (Q) is the pulmonary blood flow (blood flow to alveolar capillaries).

Question 9

What is the structure of the lungs?

Answer 9

The right lung has 3 lobes (upper, middle and lower lobes) with two fissures (horizontal and oblique fissures). The left lung has two lobes (upper and lower lobes) with one fissure (the oblique fissure).

Question 10

What are the borders of the lungs?

Answer 10

ANTERIORLY
- Apex: approx. 2.5cm above the clavicle
- Base: anterior to rib 6 (laterally to rib 8)
- Horizontal fissure: on right lung, just above level of 4th rib (nipple on males)
POSTERIORLY
- Apex: C7 approx.
- Base: T10 approx.
- Oblique fissure: runs from T3/4

Question 11

What are the pleura?

Answer 11

Two thin serous membranes that line and surround the lungs. The visceral pleura attach to the lungs, and the parietal pleura attach to the chest wall.

Question 12

What is the function of the pleura?

Answer 12

They protect and cushion the lungs. This tissue secretes a small amount of fluid that acts as a lubricant, allowing the lungs to move smoothly in the chest cavity while breathing

Question 13

What is the function of the pleural cavity?

Answer 13

To provide lubrication to reduce friction when the lungs inflate and recoil during breathing.

Question 14

What creates negative pressure in the pleural cavity?

Answer 14

1. The lungs are elastic and want to recoil inwards
2. The chest wall wants to expand outwards
3. Because the two pleural surfaces are pulling in opposite directions it creates negative pressure in the pleural cavity.

Question 15

What are respiratory muscles?

Answer 15

These are the muscles that act spontaneously and continuously to allow us to breathe. Primary muscles of inspiration are diaphragm, external intercostals and scalenes. No muscles required during expiration.

Question 16

What are static lung volumes?

Answer 16

A measurement of the volume of gas within the lung: at rest, how much air we breathe in/out during normal breathing, at full inspiration, and at full expiration

Question 17

What changes static lung volumes?

Answer 17

Lung volumes change during exercise (e.g. Vt increases while inspiratory reserve volume decreases), during respiratory disease, in obstructive disease, in restrictive disease, or after anaesthesia/surgery.

Question 18

Define tidal volume (Vt)

Answer 18

Vt is the volume of gas inspired/expired with each breath (e.g. 500ml).

Question 19

Define vital capacity (VC)

Answer 19

VC is the volume of gas expired after a maximum inspiration to a maximum expiration (e.g. 4L)

Question 20

Define residual volume (RV)

Answer 20

RV is the olume of gas remaining in the lungs after a maximal expiration (cannot be exhaled, e.g. 1L)

Question 21

Define functional residual capacity (FRC)

Answer 21

FRC is the volume of gas in the lungs at the end of a normal (passive) expiration (e.g. 2.5L)

Question 22

Why is FRC important?

Answer 22

FRC is important as it is a reserve for gas exchange and it minimises the work of breathing. FRC is determined by the balance of inward lung elastic recoil and outward pull of chest wall

Question 23

Define residual volume (RV)

Answer 23

RV is the volume of gas remaining in the lungs after a maximal expiration (cannot be exhaled, e.g. 1L)

Question 24

Define total lung capacity (TLC)

Answer 24

TLC is the volume of gas in the lungs after a maximal inspiration (e.g. 5L)

Question 25

Define residual volume (RV)

Answer 25

RV is the olume of gas remaining in the lungs after a maximal expiration (cannot be exhaled, e.g. 1L)