PHS 301 Respiratory Physiology

Question 1

What is tidal volume and it’s approx?

Answer 1

Tidal volume (TV). It is the volume of air inspired or expired with each breath during normal quiet breathing.
It is approximately 500 mL in normal adult male.

Question 2

What is Inspiratory reserve volume (IRV) and it’s approx?

Answer 2

Inspiratory reserve volume (IRV). It is the extra volume of air that can be inhaled by a maximum inspiratory effort
over and beyond the normal tidal volume. It is about 3000 mL (range 2000-3200 mL) in a normal adult male.

Question 3

What is Expiratory reserve volume (ERV) and it’s approx?

Answer 3

It is the extra volume of
air that can be exhaled by the maximum forceful expiration over and beyond the normal tidal volume, (1.e. after the end
of normal passive expiration). It is approximately 1100 mL in a normal adult male.

Question 4

Residual volume (RV) and it’s approx

Answer 4

It is the volume of the air that stil
remains in the lungs after the most forceful expiration. It is about 1200 ml in a normal adult male. RV can be calculated from function residual capacity.

Question 5

What is Inspiratory capacity it’s approx and formula

Answer 5

This is the maximum volume of
the air that can be inspired after normal tidal expiration.
Therefore it equals the tidal volume plus inspiratory reserve volume (TV + IRV) and is approximately 3500 mL in a normal adult male.

Question 6

What is Expiratory capacity approx and formula?

Answer 6

It is the maximum volume of air
that can be expired atter normal tidal inspiration. It equals tidal volume plus expiratory reserve volume (TV + ERV) and is approximately about 1600 mL in a normal adult male.

Question 7

What is Functional residual capacity, it’s approx and value?

Answer 7

It is the volume of the air remaining in the lungs atter normal tidal expiration. Therefore it equals the expiratorv reserve volume plus the residual volume (ERV+ RV)and is about 2300 ml in a normal adult male

Question 8

Components of the upper respiratory tract

Answer 8

nasal cavity
paranasal sinuses
pharynx
larynx above the vocal cords

Question 9

Components of the lower respiratory tract

Answer 9

lungs
alveoli
bronchi
bronchioles
larynx below vocal cords
trachea

Question 9

Function of the nasal cavity

Answer 9

The nasal cavity functions to humidify, warm, filter, and act as a conduit for inspired air, as well as protect the respiratory tract through the use of the mucociliary system.
Mucus in the cavity traps inhaled particles whilst cilia drive mucus towards the throat to be swallowed
Inhaled bacteria are destroyed by lysozymes in the nucleus, lymphocytes and antibodies IgA
The nasal cavity also houses the receptors responsible for olfaction in the lining of the roof of the cavity

Question 10

Function of the bronchi

Answer 10

distribute the air throughout the lungs until reaching the respiratory bronchioles and alveolar sacs
They dialiate and contrict to control airflow

Question 11

Function of the larynx

Answer 11

protect the lower respiratory tract from aspirating food into the trachea while breathing by mechanism of the epiglottis. It also contains the vocal cords and functions as a voice box for producing sounds, i.e., phonation.

Question 11

Function of the pharynx and its divisions

Answer 11

supports your respiratory and digestive systems.

Routes air coming from your nose and mouth down to your larynx (voice box), which, in turn, moves air to your trachea and lungs.

Delivers food and liquid to your oesophagus, which sends them onto your stomach

oropharynx:
nasopharynx
laryngopharynx

Question 12

Function of the paranasal sinus

Answer 12

decreasing the relative weight of the skull, increasing the resonance of the voice, providing a buffer against facial trauma, insulating sensitive structures from rapid temperature fluctuations in the nose, and humidifying and heating inspired air.

Question 13

Function of the trachea

Function of the alveoli

Answer 13

transports air in and out of your lungs while also conditioning air

this is the site of gaseous exchange where O2 moves in blood in capillaries and CO2 is diffused from blood to alveoli to be exhaled into small air sacs

Question 14

Function of the bronchioles and mention its divisions from trachea to alveoli

Answer 14

to deliver air to a diffuse network of around 300 million alveoli in the lungs.

Trachea
Primary Bronchi
Secondary Bronchi
Tertiary Bronchi
Bronchioles
Terminal Bronchioles
Respiratory Bronchioles
Alveoli

Question 14

Function of the lungs

Answer 14

draw oxygen from the air and transport into the bloodstream and remove carbon dioxide from the blood

Question 15

Non-respiratory frunction of the immune system

Answer 15

Epithelial cells in the mucosal lining of the conducting zone secrete
various molecules that are involved in lung defense mechanism. These include secretory immunoglobulins (IgA), collectins, surfactant proteins
—(SP-A) and (SP-D), defensins, chemokines, cytokines, etc.

Question 15

What is asthma?

Answer 15

Asthma
Asthma is considered an inflammatory disease of the bronchioles caused
by the hypersensitivity of the bronchioles to foreign substances in the air.
Asthma is a chronic life-long disease with periods of remissions and
exacerbation

Question 16

Cause of asthma

Answer 16

Functional abnormality in asthma is airway narrowing produced by
following effects of allergic reactions:
* Spasm of bronchial smooth muscle, which is triggered by exposure to
provoking agents such as allergen or exercise,
* Inflammation of bronchial wall (predominantly eosinophilic/producing
mucosal oedema) and
* Secretion of thick mucus into the lumen of bronchioles.

Question 17

What is the mechanicanism of breathing?

Answer 17

This describes the mechanics that take place to allow a person to inhale and exhale air

Question 18

2 main physical values involved in breathing

Answer 18

volume
pressure

Question 19

What is inspiration?

Answer 19

refers to the inflow of air into the lungs when intrapulmonary pressure falls below atmospheric pressue

Question 20

What is expiration?

Answer 20

refers to the outflow of air from the lungs into the atmosphere when intrapulmonary pressure rises above the atmospheric pressure

Question 21

What are the muscles of normal tidal inspiration?

Answer 21

diaphragm
external intercostal muscles

Question 22

Accesory muscles of inspiration

Answer 22

scalene
sternomastoid
serratus anterior
alae nasi

Question 23

Muscles of expiration

Answer 23

internal intercostal
abdominal muscles (rectus abdominis, transversus abdominis and internal olblique

Question 23

When are accesory muscles employed?

Answer 23

In situations that require increased inspiration e.g. in respiratory distress accessory muscles are required

Question 23

Discuss the process of inspiration

Answer 23

Diaphragm: flattens, moves downwards and contracts
Thoracic cavity: increases in size (volume) resulting in a decrease in pressure
Lungs: expand allowing air to enter the lungs
Ribs: move upwards and sternum moves forwards
Muscles: external intercostal muscles elevate the ribs, they are attached to the ribs infero-anteriorly from the lower to upper border of the rib.
Due to the direction of these fibers, when they contract, the ribs move up via the bucket- and pump-handle effects.

Question 24

Discuss the process of expiration

Answer 24

Diaphragm: relaxes to its resting position
Thoracic cavity: reduces in volume
Lungs: contract and air is expelled
Ribs: come down and the sternum moves back
Muscles: because quiet expiration is passive, it doesn’t require the muscles to move

Question 25

What muscles are required during forced expiration?

Answer 25

internal intercostal (attached between ribs infero-posteriorly): they work to depress the ribs
Abdominal muscles: they pull the ribs down and increase abdominal pressure so they can also elevate the diaphragm.

Question 26

What is meant by the elastic recoil of the lungs?

Answer 26

The elastic recoil of lung tissue allows them to return to their original size after expansion during inspiration

Question 27

Besides their role in deep breathing, the expiratory muscles are also
involved in other forced expiratory efforts such as

Answer 27

in coughing, vomiting, defaecation and Valsalva manoeuvre, etc.

Question 28

What is Valsalva maneuver is_____________

Answer 28

the performance of forced expiration against a closed glottis.
Many activities of our daily lives, such as straining during defecation or playing the saxophone entail the performance of the Valsalva maneuver.