RES Lectures 14 - 18

Suggest a typical resting VO2 and VCO2 respectively.

The law of partial pressure is also known as:

Dalton's law is Pgas = Fgas * Ptotal

Sternocostal joints (connecting the sternum to the ribs) are all [blank_start]synovial[blank_end], except the first which is [blank_start]cartilaginous[blank_end]. The costochondral (rib to cartilage) joints are [blank_start]cartilaginous[blank_end] joints and the interchondral joints (cartilage to cartilage) joints are [blank_start]synovial[blank_end]. Costal cartilage is [blank_start]hyaline[blank_end].

The ribs join the vertebrae posteriorly as [blank_start]bi-lateral[blank_end] facets. Two [blank_start]synovial[blank_end] joints per rib: the costotransverse and costovertebral joints.

The mediastinum is one of the cavities of the thorax, containing:

The left pleural cavity is smaller than the right pleural cavity, because

The diaphragm is innervated to contract via which nerve, exiting which levels of the spine?

Which set of intercostals is used during inspiration?

What direction do the internal intercostals run in?

What direction do the external intercostals run in?

Serous membranes secrete [blank_start]serous fluid[blank_end]. Within the thorax, there are two serous membranes: the [blank_start]visceral[blank_end] pleura which covers the lungs and the [blank_start]parietal[blank_end] pleura which lines the thorax and [blank_start]mediastinum[blank_end]. In between these pleura lies a potential space.

Expiration is mostly passive.

Calculating pO2: If O2 = 21% of air, and PB = 760mmHg, what is the pO2 of inspired air?

The intrapleural space creates [blank_start]sub-atmospheric[blank_end] pressure which suctions the lungs to the thoracic wall, helping [blank_start]inflate[blank_end] them when the diameter of the thorax is [blank_start]increased[blank_end] via muscle movement. A puncture to the pleura may cause an air bubble and significant breathing problems—this is a [blank_start]pneumothorax[blank_end].

Choose the statement that most accurately describes 'The Work Of Breathing'.

Someone with fibrosis or emphysema will have to do more work to expand the lungs.

What do we call the fluid used to decrease surface tension in the lungs?

What percent of cells of the alveoli do the phospholipid secreting type II pneumocytes make up?

What property of the lung must be increased to decrease the work associated with inflation?

Surfactant is not produced in the fetal lungs until the [blank_start]sixth[blank_end] month. Premature infacts lacking surfactant is known as [blank_start]neonates[blank_end] or Respiratory Distress Syndrome and can lead to alveolar [blank_start]collapse[blank_end] and [blank_start]fluid[blank_end] filled lungs. Lack of surfactant is adults is Adult Respiratory Distress syndrome and can be seen in [blank_start]trauma[blank_end] victims.

Which law explains the relationship between flow resistance and vessel radius?

If you halve the radius of a vessel, you double the airway resistance.

Which airways/structures contribute the most to resistance?

Which of these is not a reason to use spirometry?

What can't you measure with spirometry?

What does FEV1 stand for?

Why might the FEV1 be reduced? (Choose all correct)

What FEV1/FVC ratio indicates obstruction?

Spirometry can identify a [blank_start]decreased[blank_end] lung capacity, caused by a [blank_start]restrictive[blank_end] lung disease e.g. fibrosis. It can also identify [blank_start]increased[blank_end] airway resistance, caused by [blank_start]obstructive[blank_end] lung disease e.g. asthma.

How can you calculate VE?

Approximately how much of the tidal volume is dead space?

Which equation can be used to calculate alveolar ventilation?

Hyperventilation occurs when...

The [blank_start]respiratory ratio[blank_end] (R) is the ratio of carbon dioxide consumption to oxygen consumption. If VCO2 is typically [blank_start]250-300[blank_end]ml/min, and VO2 is typically [blank_start]200-250[blank_end]ml/min, R is commonly 0.8.

[blank_start]Fick[blank_end]'s Law describes the diffusion of gases into the blood. Which the alveolar wall is [blank_start]thick[blank_end], which would slow it down, the [blank_start]very large[blank_end] alveolar surface area compensates. The main driving force for diffusion is the [blank_start]pressure difference[blank_end]. Emphysema is characterised by the dilation and destruction of alveolar spaces. This decrease in the [blank_start]surface area[blank_end] leads to a [blank_start]low PO2[blank_end] in the blood. In pulmonary fibrosis, alveolar wall [blank_start]thickening[blank_end] leads to a [blank_start]low[blank_end] PO2 in the blood.

Choose the three things PO2 depends on.

PACO2 (pressure of CO2 in the alveoli) must be a controlled value. At what mmHg is PACO2 constantly kept?

For each mmHg of O2 dissolved in the blood, you can only dissolve [blank_start]0.03[blank_end]ml of O2 per litre. This is ineffective, so we used haemoglobin. For every gram of Hb, you can carry [blank_start]1.34[blank_end]ml O2. Your capacity to carry O2 is therefore your [blank_start]grams of Hb x 1.34[blank_end]. However, this capacity suggests 100% saturation. Your O2 content is the actual O2 you carry. You can calculate O2 content by (grams of Hb x 1.34 x [blank_start]saturation of Hb as a proportion[blank_end]) + 0.03 x PaO2. The last part you add on to account for [blank_start]dissolved[blank_end] O2 in the blood.

If you minus PvO2 from PaO2, you can tell:

The a-v difference is normal ~ 50mL but can increase up to ~ 150mL when exercising.

Formation of COHb will shift the saturation curve of pO2 to the right.

During exercise, the saturation curve of Hb will shift to the left.

What might cause a left shift of an Hb/O2 saturation curve?