Respiratory Study Questions

Question 1

What are the key functions of the respiratory system?

Answer 1

• Gas exchange: oxygen delivery and carbon dioxide removal
• Regulation of pH of body fluids: CO2 + H2O ←→ H+ + HCO3=
• Temperature control
• Voice production

Question 2

What are the two key respiratory gases?

Answer 2

Oxygen and Carbon Dioxide

Question 3

What is partial pressure?

Answer 3

The amount of pressure exerted by a particular gas in a mixture
-Influenced by the # of molecules

Question 4

What is a gas exchange membrane? How do gases get to the exchange membrane? How do they cross it?

Answer 4

• Layers of tissues that separates the internal tissues from the external environment – “breathing organ”
• Reach the membrane by convection transport (ventilation and circulation)
• Cross membrane via diffusion

Question 5

In mammals and birds, what membranes do gases need to cross?

Answer 5

Mammals - Alveolar membrane and Capillary membrane

Birds - No alveoli, so parabronchi is site of gas exchange
Mvmt between parabronchi and air capillary by diffusion

Question 6

What factors control the rate of gas diffusion?

Answer 6

• Membrane surface area
• Difference in partial pressures
• Distance btwn 2 partial pressures (membrane thickness)
• The gas, the temperature, the phase, membrane permeability

Question 7

Why is it advantageous to have an expansive, but very thin gas exchange membrane?

Answer 7

Thinner membrane = less distance to travel therefor faster exchange.
Expansive = more area to pass through so more area to exchange.

Question 8

List the parts of the respiratory system: (10)

Answer 8

Conducting Airways:
1. Nasal passages
2. Pharynx
3. Larynx
4. Trachea
5. Mucous cells
6. Bronchi, bronchioles, alveoli
          Part of the lungs 
          Alveoli
Other Components: 
-Diaphragm
-Intercostal muscles (external and internal)
-Pulmonary artery
-Pulmonary vein

Question 9

Pharynx

Answer 9

Cavity at the back of nasal passages and the mouth

Question 10

Larynx

Answer 10

Regulates air flow, expels foreign objects, contains vocal cords

Question 11

Trachea

Answer 11

Long tube

Question 12

Mucous cells _______ while ciliated cells ___________.

Answer 12

Mucous - lubricate

Ciliated - remove impurities

Question 13

Alveoli

Answer 13

Gas exchange surface, thin walled, excellent blood supply

Question 14

Pulmonary artery takes _________.

Answer 14

Blood to lungs

Question 15

Pulmonary vein takes _________.

Answer 15

Blood from lungs to the heart

Question 16

What are the major muscle groups involved in breathing in mammals? In birds?

Answer 16

Breathing animals:
     -External and internal intercostals
     -Abdominal muscles
Birds:
     -Internal intercostals
     -Thoracic muscles

Question 17

Describe how air moves through the airways in mammals.

Answer 17

• O2 diffuses across the alveolar membrane and capillary endothelium
  
  • High PO2 (air in alveoli) to low PO2 (blood in capillaries)
  • CO2 moves in opposite direction

Question 18

Conducting vs. Respiratory airways

Answer 18

Conducting: Airway up until gas exchange (i.ei. nasal cavity, air sacs)
Respiratory: Site of gas exchange (i.e. alveoli, parabronchi)

Question 19

What are the parts of the avian respiratory system?

Answer 19

Nasal cavity
Larynx
Trachea
Anterior and posterior air sacs
Parabronchi
Lungs

Question 20

Air sacs help with…

Answer 20

Movement of airflow through the parabronchi because birds do not have a diaphragm.
-Lungs are less elastic and do not change volume so the air sacs make up for that by their ability to expand and contract

Question 21

What part do mammals have that birds do not?

Answer 21

Pharynx

Question 22

The mammal’s lungs ________ than the avian’s.

Answer 22

Stretch farther

Question 23

Inspiration in mammals requires…

Answer 23

Coordinated muscle contraction by the external intercostal muscles and diaphragm.

Question 24

3 Steps for Inspiration in mammals

Answer 24

1. Rib cage pulled up and out (external intercostal)
2. Diaphragm descends which creates a vacuum
3. Lungs volume expands, air pulled into airways

Question 25

Steps for Expiration in mammals

Answer 25

Expiration is muscle relaxation normally. 1. Neurons of inspiration are inhibited 2. muscles relax 3. rib cage returns to ‘normal’ position 4. pressure increases pushes air out of alveoli 2. Internal intercostals and the abdominal muscles are involved when it is forced expiration by bringing internal intercostals and abdominal muscles up to further force air out of lungs

Question 26

Why is the composition of air in the alveoli different from that in the atmosphere?

Answer 26

To get from the atmosphere into the bloodstream, oxygen must diffuse across 2 sets of membranes (alveolar and capillary) and to be able to cross via diffusion it must go from a high concentration to a low concentration.

Question 27

Amount of air that comes into and out of the lungs during each breath

Answer 27

Tidal volume

Question 28

Maximum amount of air that can move into and out of the lungs during breathing.

Answer 28

Vital capacity

Question 29

Amount of air that cannot be forcefully expired from the lungs.

Answer 29

Residual volume

Question 30

Amount extra over tidal volume that could be inhaled

Answer 30

Inspiratory reserve volume

Question 31

Amount extra air that could be exhaled with force.

Answer 31

Expiratory reserve volume

Question 32

Equation for Respiratory Minute Volume

Answer 32

Tidal volume * RR

Question 33

What areas of the brain are involved with the control of respiratory rate?

Answer 33

- Normal breathing is reflexive → autonomic neurons in the medulla - Ventilator neurons in the pre-Botzinger complex of the medulla initiate the breathing rhythm - Neurons depolarize at a rhythm → action potential → external intercostals & diaphragm → inspiration -Not depolarized = no action potential, muscles relax, expiration

Question 34

What different “chemical” factors regulate the respiratory rate? How? Why?

Answer 34

Factors that increase respiration rate: - Decrease in PO2 - Increase in PCO2 - Decrease in pH Chemoreceptors are the main sensory input for R.R and keep those 3 constant in the blood.

Question 35

What non-chemical factors can regulate respiratory rate?

Answer 35

Exercise

Question 36

Aside from chemical mediators, what else may be involved in controlling respiration during exercise?

Answer 36

a. Motor neurons b. Sensors in limbs c. Thermoregulation d. Psychological factors

Question 37

Describe airflow through the avian respiratory system during inspiration and expiration.

Answer 37

- Through parabronchi from posterior to anterior - Posterior air sacs fill with fresh air → go to parabronchi (site of exchange) → stale air from the parabronchi and anterial air sacs is exhaled via primary bronchi

Question 38

What factors regulate the respiratory rate in birds?

Answer 38

a. CNS control in the pons and medulla b. Chemoreceptors for PCO2 PO2 and pH c. Mechanoreceptors d. Thermoreceptors

Question 39

Birds hyperventilate in...

Answer 39

Heat stress, activity, and altitude | -Breathe less frequently than similarly-sized mammals but take larger breaths.

Question 40

Describe the structure of hemoglobin and how it may vary based on the tissue.

Answer 40

a. Hemoglobin = heme (porphyrin group – ring structure with Fe+) + globin (protein chain) - Blood hemoglobins = 4 heme + globin molecules - Muscle myoglobins = 1 heme group + globin

Question 41

What are the key roles of hemoglobin? (4)

Answer 41

a. Increase the O2 carrying capacity of blood b. Regulation of blood pH (buffer) c. CO2 transport through the blood d. O2 storage in tissues (myoglobin)

Question 42

Describe the relationship between blood PO2 and the oxygen content of the blood.

Answer 42

PO2 is determined entirely by how much dissolved O2 is in the blood.

Question 43

In what form (i.e. dissolved, bound, etc.) is the majority of blood oxygen?

Answer 43

Bound to hemoglobin

Question 44

What sets of membranes does O2 need to cross to get from the alveoli to bind to hemoglobin?

Answer 44

a. Alveolar membrane (into and out of cell) b. Capillary endothelium (into and out of cell) c. RBC membrane (into cell)

Question 45

What is meant by the term ‘oxygen carrying capacity’?

Answer 45

- The oxygen content of the blood when all hemoglobin is saturated with O2 - Dependent on how much hemoglobin is in the blood (# of RBC, amount of iron)

Question 46

What drives oxygen movement from the blood into the tissues and how does this relate back to the oxygen dissociation curve?

Answer 46

- Oxygen must be released from the hemoglobin to diffuse across membranes into the tissues, so its beneficial for less O2 to bind to hemoglobin in the lungs - Oxygen must be released from the hemoglobin to diffuse across membranes into the tissues.

Question 47

What do we mean when we say that hemoglobin’s affinity for oxygen is high under a certain physiological situation?

Answer 47

a. How likely it is that O2 will be bound by the hemoglobin at a given PO2 b. At a given PO2 i. High affinity = higher saturation c. At a given % saturation i. High affinity = lower PO