Anatomical Correlates of Respiratory system: Wilson

Question 1

What are the two major factors important in increasing vascular resistance thus reducing blood flow through the lungs?

Answer 1

• reduced inflation of the lungs (because of mechanical limitations imposed by the deformed rib cage); when you take a breath the expansion of the CT that expand the BV themselves
• hypoxia (a potent stimulus for vasoconstriction); because the blood is not being fully oxygenated a major stimulus will induce vasoconstriction

Question 2

In the fetus, the lungs are collapsed. How does this affect pulmonary resistance?

Answer 2

• increased pulmonary resistance
• pressure is higher in pulmonary vessels than systemic vessels resulting in a right to left shunting of blood through the foramen ovale

Question 3

When the lungs are fully inflated, how is blood flow through the lungs affected?

Answer 3

resistance to pulmonary blood flow goes up

Question 4

When the lungs are fully expanded, pulmonary resistance goes up because of compression of the?

Answer 4

pulmonary capillaries by the ballooning alveoli

when you take a very deep breath the alveoli themselves expand to the maximal extent putting pressure on the capillaries associated with the alveoli collapsing those capillaries

Question 5

To keep blood flow constant, an increase in pulmonary resistance results in pulmonary blood pressure that does what?

Answer 5

goes up

Question 6

What anatomical changes do you see? What are the underlying physiological mechanisms? What are the pathological causes?

Answer 6

enlargement of the pulmonary trunk and arteries, thickening of wall of RV, dilation of both RA and RV

when you see abnormal anatomical symptoms it works back to what are the physiological changes and how they express in the clinic during physical examinations

Question 7

What is cor pulmonale?

Answer 7

• due to diseases of the lung (bronchitis, emphysema)
• increase in pulmonary resistance can result in pulmonary HTN (an increase in BP in the pulmonary trunk)
• blood is pooling in the arteries going to the lung

increased resistance in blood flow to the lungs and thus the heart has to pump harder with greater pressure; expansion of pulmonary trunk and arteries; RA and RV is dilated and RV wall is thickened

• can result from severe kyphoscoliosis: severe deformities of the vertebral column in the thoracic region
• is an example of right heart failure
• in extreme cases, cardiorespiratory failure and death may result

Question 8

What are the changes you would observe systemically in right heart failure?

Answer 8

• ascites (veins in the portal system)
• distention/engorgement of the EJV
• elevated venous pressure
• enlarged and tender liver (hepatomegaly tender to palpation) as well as splenomegaly
• cyanosis
• edema around the ankles
• dilation of right heart
• You would NOT see pulmonary congestion
• Right heart failure results in congestion in the systemic system.

-hilar vascular and dilated pulmonary trunk in cor pulmonale

Question 9

T/F. Output of the left side of heart has to match output of right side of heart.

Answer 9

True

Question 10

What is the hepatojugular reflex?

Answer 10

when you compress the liver pushing all the blood towards the heart

if you have right heart failure you would see distension of the external jugular vein in the neck; you would not see this in a normal patient lying down

• this is a positive sign of right heart failure
• normally when you deliver more blood to the right side of the heart, the heart muscle because it has a greater volume of blood and is being stretched will contract and pump harder but when the heart is diseased or damaged in right heart failure it cannot compensate

Question 11

How are the alveoli in the lungs expanded, how do they inflate?

Answer 11

when you expire the diaphragm relaxes in dome shaped reducing the size of the thoracic cage

when you inspire there is contraction of the diaphragm which flattens and goes towards the abdomen increasing the size of the thoracic cage and size the pleural cavity has no outlet
to the atmosphere normally speaking the air pressure becomes negative generating a vacuum; you increase the volume of the thoracic cavity decreasing the volume of the abdomen

positive pressure inside the alveoli pushing out against the negative pressure outside the alveoli and the lungs expand

Question 12

During inspiration, where is air pressure is lowest?

Answer 12

-pleural cavity (pressure between visceral and parietal pleura) is negative; it’s in a vacuum; because you have this pressure differential across the alveolar wall with atmospheric pressure inside the alveoli and negative pressure outside the alveoli the alveoli will expand when you expand the thoracic cage

alveoli, bronchi, and trachea are close to atm pressure

Question 13

For lungs to expand normally what is necessary?

Answer 13

• thoracic wall is structural sound

- pleural cavities themselves remain empty (very little amount of serous fluid), potential spaces

Question 14

What are two other major condition that result in damage to the thoracic cage producing changes in respiration?

Answer 14

• flail chest

- pneumothorax: blowing and positive pressure

Question 15

What is flail chest?

Answer 15

when you have multiple fractures of the thoracic cage resulting in an unstable or floating portion of the thoracic cage (it moves independently of the thoracic cage as a whole) OR
when the sternum has become detached from the ribs themselves producing movements of the rib cage

Question 16

What are the consequences of flail chest?

Answer 16

paradoxical breathing

During inspiration the flail wall moves in, opposite to direction to the expanding chest because of the negative pressure the unstable ribs will be sucked in and the lung cannot expand to the normal size; air is actually pulled out of it collapsing the lung; unstable part is moving the opposite direction of inflation expanding chest; you get a mediastinal shift from side of injury to opposite side thus the normal side will not be compressed and not be able to inflate to its normal extent as well

you can push dead air space (bad) into the lung getting a mixture of good and bad air??

during expiration and contraction of the chest area, the flail wall moves outward in the opposite direction; the unstable portion will expand outwardly; the mediastinum will shift to the side where you are expanding; as the lung is inflating it will suck some of the bad air to the good lung

affecting blood gas

Question 17

What is the blowing or sucking pneumothorax?

Answer 17

• opening into the pleural cavity
• pleural cavity is no longer isolated from the atmosphere
• when you inspire AKA expand the chest cage air will be sucked in as the air pressure goes into the pleural cavity, the lung will collapse
• the heart and great vessels get pushed over to the opposite direction
• underinflation of the normal side of the wall

during expiration, you are pushing air out of the pleural cavity on the side where you have the wound and thus the mediastinum will shift towards the direction of expiration; the size of the pleural cavity on intact size increases and therefore trying to expire all the bad air is reduced

Question 18

What is the mediastinal shift?

Answer 18

the heart and great vessels is shifting to the left in inspiration and to the right in expiration with an open (sucking) pneumothorax to the right lung

Question 19

What should you do if someone comes in with pneumothroax?

Answer 19

• cover the wound with gauze or whatever
• put a tube onto the side where you have a pneumothorax that allows air to escape from the pneumothorax but does not allow back in; the air inside the pleural cavity will be removed and the vacuum will be restores allowing patient to breathe normally

Question 20

What is Positive Pressure (Tension) Pneumothorax?

Answer 20

sometime pneumothorax can be caused by a bullae or blister on the wall of the lungs; when they rupture it releases air into the pleural cavity

initially the effect is the same as the sucking or blowing pneumothorax

as you inspire you get a positive pressure in the pleural cavity causing collapse of alveoli lungs and mediastinal shift to the opposite side

the volume in which the normal lung can expand is reduced

the difference is during expiration: soft tissue that forms like a valve, the air is trapped and every time you take a breathe more air comes in but does not escape to the atmosphere: the mediastinum gets more displaced to the opposite side

Question 21

The increasing pressure augments mediastinal shift by?

Answer 21

• trachea will be deviated towards intact side
• the contralateral ung will be compressed and ventilation will be impaired
• diaphragm will be depressed on the side of the positive pressure or tension (the air pressure is pushing the diaphragm down)
• IVC goes through diaphragm and thus venous return to the heart is impaired

Question 22

What ar clinical manifestation of positive pressure pneumothorax?

Answer 22

hyper-resonance as there is nothing inside there but air

Question 23

What is the most common cause of positive pressure pneumothorax?

Answer 23

rupture of bullae

air filled blisters on the surface of an emphysemic lung tha release air into the pleural cavity reducing the vacuum producing a pneumothorax

Question 24

What is the chylothorax?

Answer 24

the space into which the lungs will expand is being filled with blood and thus is reduced

you must aspirate the fluid away to restore the space into which the lung can expand

Question 25

What is thrombus?

Answer 25

a blood clot in a blood vessel

Question 26

What is an embolism?

Answer 26

a plug; an obstruction of a blood vessel that has been transported from one side to another

so an embolism could be formed by a blood clot of mass of bacteria or foreign material

Question 27

When you have a thrombus that breaks free where does the plug get stuck?

Answer 27

• arteries get progressively smaller; the plug will get stuck when the size of the BV is the same as the clot
• if the clot is in the legs vein get bigger and bigger but gets smaller after the heart as veins gets smaller

Question 28

What are the predisposing factors for a pulmonary embolism?

Answer 28

-prolonged bed rest; as long as blood is moving clots usually will not form; blood can pool and provoke the formation of a clot

• prolonged sitting
• varicose veins
• right heart failure
• oral contraceptives
• fracture to the lower limb (hip fx, hip replacement; uterus surgery); clots can break free and form pulmonary embolism
• after giving birth to a child

Question 29

If you follow the blood going from the lesser saphenous vein to the lower limb, at what point do vessels first begin to get smaller?

Answer 29

after the pulmonary artery

did not get the answer review unit 1

Question 30

He shows a picture with massive pulmonary embolism blocking blood flow to right side of heart. How are the ventilation and perfusion to both sides of the heart?

Answer 30

ventilation is completely fine but the perfusion going to the right side of heart is almost zero

Question 31

What are the cardinal signs of pulmonary embolism ?

Answer 31

• sudden onset of dyspnea (labored, difficulty breathing)

- tachycardia: increased heart rate because you’re not getting enough blood to the lungs

Question 32

What are the nonrespiratory functions of the lungs?

Answer 32

to filter/clear the blood system of thrombi or embolisms

Question 33

What are the symptoms of pulmonary embolism?

Answer 33

Pleural pain & breathlessness suggest infarction

Question 34

What is emphysema?

Answer 34

there is enlargement of respiratory alveoli as there is a deterioration in the alveolar septi and walls CT, loss of elastic CT; the small alveoli become large balloons; so air becomes trapped in the alveoli

remember expiration is largely passive; when you deflate the chest wall the lungs collapse like a balloon

Air becomes trapped in the alveoli during expiration.

Question 35

What is the classic presentation of emphysema?

Answer 35

pink puffer

• external dyspnea: when a person walks with 2 or 3 steps they get out of breath
• tachypnea even when sitting down
• hyper-resonance of lungs (percussion) as lungs are filled with air
• very thin body build; asthenic body build
• accessory respiratory muscles such as SCM, scalene muscles are used to overcome hypoxia (you would see a sternal lift in trying to expand the lungs as much as possible to get fresh air to the blood)
• lips are pursed; an individual with emphysema, when you expire the bronchioles collapse as they do not have the elastic CT to keep them opened up so by pursing lips it keeps the airways open a little longer to compress chest wall to get more air out
• diaphragm is flattened, inactive, and atrophied; it never relaxes fully as muscles begin to atrophy

Question 36

What are the effects of lung cancer on function of lungs?

Answer 36

tumors compress soft tissue; for example the tumors in the carinal nodes block the lumen of the bronchus reducing the amount of air that can come and go

metastasis to the hilar and carinal node could distort the trachea and collapse the right upper lobe of lung due to compression of lobar bronchus

Question 37

What occurs with cancer in lower part of right lungs?

Answer 37

can produces compression of esophagus and dysphagia

tumor near the apex of right lung can compress SVC reducing venous return from the head, neck, and upper limb

tumor in the left lung could block blood flow to the lower half of the body

Question 38

What is the superior vena cava syndrome?

Answer 38

-tumor growing at the apex of right lung compresses the SVC between the tumor and the ascending aorta (aorta is under a lot of pressure and thus it is difficult to compress it however veins are low pressure)

blood is pooling distal to obstruction

• you get edema of the face, neck, and chest
• distention of superficial veins (EJV)
• arm veins fail to drain on elevation

Question 39

Why is there development of collateral circulation in the superior vena cava syndrome?

Answer 39

body tries to bypass the blockage of venous return to the heart

note the development of collateral circulation in the veins of the chest wall

Question 40

What is a major tributary coming into the SVC?

Answer 40

azygos vein thus there is a much more serious condition if the superior vena cava is obstructed INFERIOR to the entrance of the azygos vein

Question 41

The azygos vein provides what collateral route?

Answer 41

tributaries provide an import collateral route by which blood may return to the heart if the superior vena cava is obstructed

Question 42

What are symptoms of Pancoast’s syndrome?

Answer 42

• Horner’s syndrome
• dyspnea
• skin is dry
• pupil is constricted
• atrophy of the right arm (decreased sensation or picks and needles)
• dysphonia: voice is hoarse, speaking in a whisper
• dysphagia: complains of food getting stuck with swallowing
• paralysis of 1/2 of the diaphragm

Question 43

What is Pancoast’s syndrome?

Answer 43

tumor growing into the root of the neck (thoracic inlet tumor)

structures that could be compressed are:

• vagus nerve supplying recurrent laryngeal nerve giving motor innervation to the esophagus (dysphagia)
• brachial plexus: produces sensory and motor paresthesia
• Horner’s syndrome due to sympathetic chain being compressed
• phrenic nerve running on top of the scalene (paralysis of diaphragm on one side resulting in the dyspnea)

Question 44

How does the size and shape of the thoracic cage affect breathing?

Answer 44

• they have a direct impact on the functions of the respiratory and cardiovascular systems
• thoracic cage is a space in which the lungs can expand or inflate
• if thoracic cage is changed

Question 45

If you have deformities or injuries to the thoracic wall, how will that affect breathing which in turn will affect the cardiovascular system?

Answer 45

deformities of the vertebral column reduce the volume of the pleural cavity and inflation of the lungs

Question 46

What is kyphoscoliosis?

Answer 46

combination of kyphosis and scoliosis

Question 47

What is kyphoscoliosis and what is its effects?

Answer 47

• it is a combination of kyphosis and scoliosis
• it causes a significant increase in resistance of blood flow through the lungs; this is similar to when you collapse the thoracic cage when a fetus is in utero the lungs cannot expand and thus pulmonary resistance gets sky high

Question 48

How is pulmonary fibrosis different from emphysema if they both cause decreased elasticity?

Answer 48

fibrosis is excessive connective tissue making the walls stiff or less elastic

emphysema is the deterioration of elastic connective tissue