respiratory system

Question 1

Nasal cavity

Answer 1

• add moisture to air in order for it to not irritate our airways (mucus, hair etc).
• Also mouth region

Question 2

pharynx

Answer 2

Common area of respiratory tract
* Respiratory and digestive diverge
* Flap - opens/close when breathing or swallowing

Question 3

Trachea

Answer 3

• bands of cartilage to functionally keep it open and solid so it doesn’t collapse whenever we breathe
• Air can move unrestricted

Question 4

Bronchus

Answer 4

supply air to each lung
* primary > secondary > bronchiole

Question 5

Diaphragm

Answer 5

At rest: semicircle

Contraction: pulls down and becomes flat

Question 6

right lung

Answer 6

3 lobes

Question 7

left lung

Answer 7

2 lobes, cardiac notch (where heart sits and rests)

Question 8

Bronchiole

Answer 8

• Don’t contain any cartilage
• Kind of like arteries - Made up of smooth muscles
• Control mechanism to allow air flow into underlying structure called alveoli
• Endothelial layer and smooth layer
  - Controlled to alter diameter - alter air flow

Question 9

Alveoli

Answer 9

• Terminal sacks - terminate at the end of respiratory system
• Where gas exchange occurs - functional unit

Question 10

Capillary beds

Answer 10

• Sit on top and are in very close association
• Single cell layer of capillaries allows rapid exchange between alveoli (gases) and the blood

Question 11

Partial pressure

Answer 11

each individual gas in mixture (air) will have this

Question 12

Knowing partial pressure allows us to…

Answer 12

predict gas movement

Question 13

Gases always diffuse from a region of…

Answer 13

high partial pressure to a low partial pressure

Question 14

O2 & CO2 partial pressure

Answer 14

760 mm Hg (atmospheric pressure) of all gases in atmosphere (surrounding us)
* 21% oxygen in atmosphere
- O2: 760 x 0.21 = 160 mm Hg
* 0.03% carbon dioxide in atmosphere
- CO2: 760 x 0.0003 = 0.23 mm Hg

Question 15

negative pressure breathing

Answer 15

To move O2 from atmosphere into our lungs, the pressure must be lower in the lungs
* Pulling in rather than pushing air into our lungs
* Achieved by expansion of the chest wall by muscle contraction
* Creating a gradient

Question 16

Why do our lungs expand when our chest contracts?

Answer 16

A double membrane surround the lungs

• One side adheres to the outside of the lung, the other to the wall of the thoracic cavity (ribs)
• Filled with fluid that creates surface tension

Question 17

Visceral pleura

Answer 17

on organ side (surface of lung)

Question 18

Parietal pleura

Answer 18

• Stick to the rib cage bc of surface tension and the water molecules associated with the fluid inside this space that creates hydrogen bonds (strong)
• Fluid in this space - the water molecules are attracted to each other
• When ribs/diaphragm expands it pulls the lungs with it because of these bonds
• Active process

Question 19

Breathing out - expiration

Answer 19

• Usually does not require the contraction of any muscles
• Passive process
• Relaxation of diaphragm and rib cage reduces the volume of the thoracic cavity driving air out of the lungs
  Increasing pressure - drive air out

Question 20

Lung capacity @ inflation/deflation

Answer 20

Total lung cap. at max inflat. - 5700mL
Var. in lung vol. -
* end of normal inspiration - 2700mL
* end of normal expiraation - 2200mL
Min lung vol. at max. deflat. - 1200mL

Question 21

Spirometry

Answer 21

simple, noninvasive test that measures the volume and flow of air inhaled and exhaled by the lungs
* Forced vital capacity (FVC): This is the total volume of air exhaled during the entire spirometry test.
* Forced expiratory volume in one second (FEV1): This is the volume of air exhaled during the first second of the test.
* Peak expiratory flow (PEF): This is the maximum speed of exhalation during the test.
* Forced expiratory flow (FEF): This is the average flow of air during the middle portion of the exhalation.

Question 22

What prevents the collapse of alveoli?

Answer 22

Surfactant - lines inner lining of alveoli
Hydrogen molecules attract to each other which would cause alveoli to collapse but surfactant is secreted and prevents this - minimises reaction

Question 23

Oxygen is predominantly transported around the body bound to…

Answer 23

haemoglobin within red blood cells
* 98% transported this way
* 2% dissolved in plasma

Question 24

CO2 transported by 3 different mechanisms:

Answer 24

• 7% dissolved in plasma
• Remaining 93% within RBCs but via 2 separate mechanisms
  23% bound to haemoglobin
  70% converted to bicarbonate

Question 25

Each haemoglobin molecules can carry

Answer 25

4 molecules of O2

Question 26

Oxyhaemoglobin saturation curves

Answer 26

At normal P O2 levels, haemoglobin is 98% saturated
Minor changes in P O2 do not have a significant effect on saturation
Haemoglobin is a large store for O2 within the body

Question 27

hypoxia

Answer 27

low O2 levels within the blood
* If diffusion of gases between alveoli and blood is impaired or oxygen transport in the blood is altered - hypoxia

Question 28

hypoxic hypoxia

Answer 28

low arterial PO2

Question 29

Anemic hypoxia

Answer 29

decreased total amount of O2 bound to hemoglobin

Question 30

Ischemic hypoxia

Answer 30

reduced blood flow

Question 31

Histetoxic hypoxia

Answer 31

failure of cells to use O2 because cells have been poisoned

Question 32

Obstructive lung disease

Answer 32

Asthma
Emphysemas

Question 33

Restrictive lung disease

Answer 33

Impacting expansion of lungs

Asbestosis

Question 34

Pneumothorax

Answer 34

Collapsed lung
* Break bonds connecting lungs to rib cage - changing pressures in pleural membranes will break bonds
* Air, blood, fluid fills this space and therefore lungs cannot inflate

Question 35

Involuntary responses

Answer 35

receptor driven
* sneezing
* coughing
* hiccups

Question 36

Tidal volume at rest

Answer 36

500 mL