Chapter 13

Question 1

______ initiates inspiration.

Answer 1

contraction of diaphragm and the external intercostal muscles

Question 2

As thoracic wall moves farther away from _______(lung surface), the intrapleural pressure becomes _______. The decrease in intrapleural pressure increases __________?

Answer 2

visceral pleura
more subatmospheric (decrease in pressure)
transpulmonary pressure

Question 3

P(ip), and also known as?

Answer 3

pressure surround the lungs, intrapleural fluid pressure

Question 4

Following the increase in transpulmonary pressure, the ______(s) expand. This expansion is a result of what?

Answer 4

lungs expand. the expansion of the thorax reduces alveolar pressure P(alv) below atmospheric pressure P(atm), so air moves into the lungs - and therefore into alveoli

Question 5

Expiration causes reduction in the size of the _______. This immediately makes the ________ pressure less ________. Aka the P(ip) ________. This in turn decreases the _______ pressure.

Answer 5

• thoracic cage
• intrapleural fluid pressure less subatmospheric (aka the Pip increases)
• This causes a decrease in the transpulmonary pressure P(tp)

Question 6

After transpulmonary pressure is decreased during expiration, the lungs recoil. This does what to the air in alveoli? This causes the P(alv) to be ________ than the P(atm).

Answer 6

• the air in the alveoli becomes compressed

- this causes the pressure in the alveoli to become greater than the pressure in the atm and air moves out of the lungs

Question 7

What is compliance?

Answer 7

Lung compliance is the magnitude of the change in lung volume produced by a given change in the transpulmonary pressure. AKA it is how easy we can bring air into the lungs. Measure of the lungs “stretchability”

Question 8

What conditions cause increased compliance?

Answer 8

emphysema or COPD

Question 9

What is elastance?

Answer 9

the tendency to return to initial size after distension with aid from elastin proteins. AKA how easy it is to get the air out of the lungs.

Question 10

Pulmonary surfactant is a mixture of what?

Answer 10

phospholipids and protein

Question 11

what cells secrete surfactant?

Answer 11

type II alveolar cells

Question 12

surfactant lowers what? this in turn increases what?

Answer 12

surfactant lowers surface tension at the surface of the alveoli, which increases compliance - aiding the lungs in easier expansion during inhalation

Question 13

as an alveolus gets smaller, the molecules of surfactant on its inside surface are what? thus this does what?

Answer 13

less spread out, which reduces surface tension

Question 14

machine that measures lung capacity for air

Answer 14

spirometer

Question 15

P(tp)

Answer 15

transpulmonary pressure - the pressure difference between the lungs and the atmosphere (inside and outside of the lungs)

Question 16

500mL is normal for what?

Answer 16

resting tidal volume (TV)

Question 17

What is tidal volume?

Answer 17

TV is the amount of air inhaled or exhaled in one breath during relaxed, quiet breathing

Question 18

volume of air we can move in over the tidal volume? what does this help with? number here?

Answer 18

IRV - inspiratory reserve volume. this helps with exercise. is about 3,000mL in excess of the tidal inspiration (so 6x the greater than resting tidal volume)

Question 19

volume of air we can move out over the tidal volume. number here?

Answer 19

expiratory reserve volume (ERV) - 1,200mL in excess of tidal expiration

Question 20

amount of air remaining in the lungs after maximum expiration; keeps alveoli inflated b/w breaths and mixes with fresh air on next inspiration

Answer 20

residual volume (RV)

Question 21

Total lung capacity?

Answer 21

reserve volume + expiratory reserve volume + inspiratory residual volume + tidal volume = 6L usually but there is some variation

Question 22

Amount of air remaining in the lungs after normal tidal expiration. What’s the equation?

Answer 22

Functional residual capacity (FRC) – RV + ERV = 2400mL

Question 23

the maximal volume of air a person can expire after a maximal inspiration. what is the equation?

Answer 23

vital capacity - TV + ERV + IRV

Question 24

FEV1 - what’s the protocol for this test?

Answer 24

Forced expiratory volume in one second

-take a deep breath –> tidal volume + IRV and then exhale very fast and they will measure the amount of air you got out in one second

Question 25

Lower than 60% FEV1 signifies what?

Answer 25

COPD or emphysema

Question 26

How much oxygen am I carrying to the tissues for every L of blood? Some of this depends on cardiac output, but will say it’s at _______

Answer 26

200mL of oxygen for every L of blood.

so Cardiac output x 200mL per L = amount of oxygen carried to tissues per minute.

Question 27

what causes shift to the right in the _________ curve?

Answer 27

oxyhemoglobin dissociation curve

• increase in temp
• increase in acidity
• increase in DPG

Question 28

chemoreceptors that respond to changes in the arterial blood. Where are they located? They are stimulated by:

Answer 28

peripheral chemoreceptors - carotid bodies and aortic bodies. They are stimulated by:

• decrease in P(02) - (hypoxia)
• Increase in P(CO2) (respiratory acidosis)
• Increase in H+ concentration (metabolic acidosis)

Question 29

chemoreceptors located in the __________ that respond to changes in the brain extracellular fluid. They are stimulated by _______?

Answer 29

central chemoreceptors - located in the medulla oblongata, and respond to increase in PCO2 via associated changes in hydrogen ion concentration

Question 30

GFR - healthy adults should be able to clear _______ of blood every minute.

Answer 30

120mL of blood every minute

Question 31

Small children should be able to clear _______ of blood every minute.

Answer 31

20mL

Question 32

Biologically inert polysaccharide, can be used to estimate the glomerular filtration rate since it is filtered, but not reabsorbed or secreted.

Answer 32

Inulin

Question 33

How to calculate GFR? Equation?

Answer 33

GFR = (U)(V)/(P)

GFR would be mL/min

Question 34

what is release of urine from the bladder called?

Answer 34

micturition

Question 35

bladder stays closed due to two sets of muscles?

Answer 35

internal and external sphincter

The internal sphincter is an involuntary muscle, and it responds to stretch and pressure. As the bladder fills with urine, it puts pressure on the internal sphincter, and at some point it will relax bc there is too much pressure on it.

The external sphincter is voluntary, but it is still somewhat responsive to pressure. Once the internal sphincter relaxes, the pressure goes to push on external sphincter.