Week 1 Intro/ Gas Laws

Question 1

What is the composition of the air we breath?

Answer 1

21% oxygen
78% nitrogen
1% other gases

Question 2

What are the overall functions of the respiratory system?

Answer 2

Ensure tissues supplied with O2 and CO2 produced by metabolism disposed off.

Question 2

What is sea level atmospheric pressure?

Answer 2

101kpa

Question 3

What is the partial pressure law?

Answer 3

Fraction of total pressure.
Partial pressure of a gas is proportional to the % volume of that gas in the mixture.
O2 makes up 21% of air so 21% of total pressure
101 X 0.21= 21.1 kpa

Question 4

What is boyles law?

Answer 4

Pressure of gas inversely proportional to volume (space) if temp and amount of gas remains constant.
If a given amount of gas compressed into smaller volume molecules hit wall more often and pressure will rise

Question 5

How can boyles law be applied to the lungs and inspiration/expiration?

Answer 5

In inspiration volume of air in the lungs increases so pressure decreases and falls below atmospheric pressure so air flows into lungs

In expiration volume of air in lungs decreases so pressure increases above that of atmospheric so air flows out of lungs.

Question 6

What is Charles law?

Answer 6

Increase in temp increases kinetic energy- hit walls more often so pressure increases if volume and amount of gas is constant.
Pressure directly proportional to absolute temp

Question 7

Define saturated vapour pressure?

Answer 7

Water molecules entering gas phase exert a vapour pressure.
Gas is saturated with water vapour reaches equilibrium- pressure it exerts called SVP. - depends on temp.
6.28kpa

Question 8

How does SVP effect pO2 and pN2?

Answer 8

As inhaled air is saturated with water vapour as it passes through nose it dilutes the pO2 and pN2
SVP + pO2 + pN2 = 101kpa
PO2 + pN2 = 101-6.28 = 94.72kpa
PO2 = 94.72 X 21% = 19.7kpa

Question 9

What is gas tension?

Answer 9

Gas dissolves in liquid. This exerts a tension or pressure in the liquid.
At equilibrium tension exerted by gas = partial pressure of gas in a gas mixture. - called partial pressure of gas in a liquid.

Question 10

What is the tidal volume?

Answer 10

Volume in and out with each breath during quiet respiration.

Question 11

Describe the resistance and pressure of the pulmonary circulation?

Answer 11

Low resistance, low pressure as need to accommodate entire cardiac output

Question 12

What is within the upper and lower respiratory tracts?

Answer 12

Upper is everything above cricoid cartilage- nose and paranasal sinuses, pharynx, larynx

Question 13

What is contained within the conducting and respiratory portions of the tract?

Answer 13

Conducting- nasal cavity, pharynx, larynx, trachea, primary bronchi, secondary bronchi, bronchioles, terminal bronchioles
Respiratory- respiratory bronchioles, alveolar ducts, alveoli

Question 14

What epithelia line each section of the tract?

Answer 14

Nasal cavity to bronchioles- pseudostratified ciliated epithelia with goblet cells
Terminal bronchioles- simple columnar with cilia no goblet cells
Respiratory bronchioles and alveolar ducts- simple cuboidal few cilia
Alveoli- simple squamous

Question 15

What is the respiratory function of nose and how are these achieved, and what epithelial line it?

Answer 15

Filters air, humidifies and warms air and if dry and cold would damage cells further down the system

• warmed by vessels just bellow epithelia
• humidified by watery nasal secretion where water evaporates

Sense of smell- olfactory mucosa

Pseudostratified columnar ciliated epithelia with lots of goblet cells
- mucociliary escalator

Question 16

What structures are on the lateral walls of the nasal cavity?

Answer 16

Chonchae- superior, middle and inferiorityo

Meatus In space between

Question 18

What are the 4 paranasal sinuses and what are there locations?

Answer 18

Frontal- Above eyebrows in midline
Ethmoid- in eye sockets
Sphenoid- outer edges of eyes- deep at back of conchae
Maxillary- upper cheek

Question 19

What epithelia line the paranasal sinuses, what function do they have, and where are there secretions drained into?

Answer 19

• Pseudostratifed columnar ciliated epithelial containing goblet cells
• function similar to nose- humidify and warm air
• drain into nose into Meatus of conchae

Question 20

What 3 parts is the pharynx divided into and where is each part?

Answer 20

Nasopharynx- above soft pallet
Oropharynx- to epiglottis
Laryngopharnx- bellow epiglottis

Question 21

What is attached to the nasopharynx?

Answer 21

Eustachian tube connecting to the middle ear cavity

Question 22

What is located within the larynx and what is its function?

Answer 22

Vocal cords act as valves into trachea- open during respiration, closed during swallowing

Question 23

What is the glottis?

Answer 23

Vocal cords and opening between them
Addiction or vocal cords closes glottis
Abduction opens

Question 24

What nerve supplies the intrinsic laryngeal muscles and what occurs if it is damaged?

Answer 24

Recurrent laryngeal nerve
Damage causes paralysis of vocal cord of affect side - hoarseness of voice
As nerve curves around arch of aorta and back up a problem may be intra thoracic

Question 25

What can be the problem with the absence of cartilage in the walls of bronchioles?

Answer 25

Allows the airways to constrict and almost close when smooth muscle contraction is excessive- eg asthma - more difficultly with expiration than inspiration as during expiration the bronchial walls are no longer held open by the surrounding alveoli