mechanisms of ventilation

Question 1

pleura

Answer 1

• serous membrane
• divided into parietal and visceral layers
• surround the lungs
• contains the pleural cavities
• separated by serous fluid

Question 2

parietal pleura

Answer 2

outer, lines the thoracic cavity

Question 3

visceral pleura

Answer 3

inner, covers lung following lung fissures

Question 4

the lungs

Answer 4

go above the first rib. covered by suprapleural membrane

Question 5

what is the pharynx

Answer 5

nasopharynx, oropharynx, laryngopharynx

Question 6

the epiglottis

Answer 6

important in protecting the airway- when swallowing, ensures that the food goes down the esophagus instead of the trachea

Question 7

how do we breathe?

Answer 7

• diaphragm relaxed
• diaphragm contracts, thoracic cavity expands, thoracic volume increases, intra-thoracic pressure decreases
• air drawn into lungs
• blood gets oxygenated
• diaphragm relaxes, lungs recoil, thoracic volume decreases, intrathoracic pressure increases and air expelled

Question 8

the diaphragm

Answer 8

• the most important muscle in respiration
• dome-shaped muscular partition
• separates the thorax and abdomen
• innervated by phrenic nerve: C3,4,5 keeps the diaphragm alive
• attachments:
• • anteriorly into the xiphoid process and costal margin
• • laterally to ribs 6-12
• • posteriorly to T12 vertebra

Question 9

intercostal muscles

Answer 9

• assist in inspiration and expiration
• have obliquely angles fibres from rib to rib
• the contraction of external fibres raises each rib towards the rib above, to raise the rib cage
• the contraction of internal and innermost depresses each rib to the rib below, to lower the rib cage

Question 10

accessory muscles of respiration

Answer 10

scalene muscles prevent rib 1 and 2 from descending.
SCM raises sternum.
pecs and trapezius ‘fix’ the pectoral girdle to raise rib cage

Question 11

differences with adults and children in respiration

Answer 11

babies can only breathe via abdominal breathing- newborn ribs more horizontal so cant use pump/bucket handle movements, intercostals weak. abdominal breathing is done by contracting the diaphragm. reliance on the diaphragm for breathing means high risk for respiratory failure if the diaphragm is not able to contract.

children:
nasal breathers until 4-6 weeks.
short neck and shorter and narrower airways- more susceptible to airway obstruction/ respiratory distress.
tongue is larger in proportion to the mouth- more likely to obstruct airway is child unconscious.
smaller lung capacity and underdeveloped chest muscles. have a higher respiratory rate, newborns~60 breaths/min

Question 12

use of the accessory muscles whilst at rest can be a sign of respiratory distress.

Answer 12

lungs fail to provide enough oxygen to a person's body.
2 types: NRDS and ARDS.
symptoms:
- blue coloured extremities
- rapid and shallow breathing
- rapid heart rate

Question 13

neonatal respiratory distress syndrome [NRDS]

Answer 13

affects premature babies, if they are born before their lungs are fully developed and capable of working properly. approximately half of all babies born before 28 weeks of pregnancy will develop NRDS.
20% of deaths in newborns.

Question 14

acute respiratory distress syndrome [ARDS]

Answer 14

• fluid/proteins leak from the blood vessels into the alveoli.
• lungs become stiff and so don’t work normally, breathing becomes difficult.
• mainly affects >75 age
• common causes are infection in the lungs

Question 15

asthma

Answer 15

~5.4million receiving treatment in UK.
an inflammatory disease of the airways of the lungs.
- muscles around the walls of the airways tighten
- airway become narrower
- the lining of the airways becomes inflamed.

shortness of breath, wheezing, chest tightness, coughing

Question 16

emphysema

Answer 16

in a group of diseases called chronic obstructive pulmonary disease COPD
- the over-inflated alveoli do not allow effective gas exchange.

Question 17

pneumonectomy

Answer 17

removal of a lung