Respiratory System

Front 1

What are the 4 primary functions of the respiratory system?

Back 1

1) Exchange of gases between atm and blood
2) Homeostatic regulation of body pH
3) Protection from inhaled pathogens and irritating substances
4) Vocalization

Front 2

What is lost from the body through the respiratory system besides CO2?

Back 2

Water and heat loss

Front 3

Distinguish between cellular respiration and external respiration

Back 3

CELLULAR RESPIRATION: Take O2 and nutrients -> CO2, water, and ATP as products

EXTERNAL RESPIRATION: take in O2 and take out CO2

Front 4

Distinguish between inspiration and expiration.

Back 4

Inspiration: Movement of air into the lungs

Expiration: Movement of air out of the lungs

Front 5

Name the structures of the upper and lower respiratory system, following an O2 molecule from air to the exchange surface of the lungs. Briefly describe the anatomy of each section.

Back 5

UPPER: Mouth, nasal cavity, pharynx, larynx
LOWER: trachea, left and rich lung, right and left bornchus, diaphragm

From pharynx -> larynx -> trachea -> left primary bronchus -> secondary bronchus -> bronchioles -> alveoli

Front 6

What bones and muscles form the thoracic cage? The floor? Name them.

Back 6

Thorax is bounded by the bones of the spine (sternocleidomastoids and scalenes) and rib cage (intercostal muscles)

Diaphragm (skeletal muscle)

Front 7

Name the three sacs enclosed within the thorax. What is in each sac?

Back 7

Pericardial sac: heart
Pleural sacs: lungs

Front 8

What is the relationship between the lungs, the pleura, and the pleural fluid?

Back 8

The lungs are like the air-filled ballons; the balloon is the pleural membrane, and inside the ballon are fluid.

Front 9

What purpose does pleural fluid serve?

Back 9

Moist, slippery surface so that the opposing membranes can slide across one another as the lungs move within the thorax.

Holds the lungs tight against the thoracic wall

Front 10

Which air passages of the respiratory system are collapsible?

Back 10

Bronchioles, because they have only smooth muscle.

Front 11

List three functions of the upper airways and bronchi in addition to simply being passageways.

Back 11

1) Warming to body temperature so that core body temperature doesn't change and alveoli aren't damaged b/c of cold air

2) Adding water vapor until air is 100% moist and exchange epithelium doesn't dry out

3) Filtering out foreign material, so that viruses, bacteria, and inorganic particles do not reach the alveoli

Front 12

Describe and give the functions of the two types of epithelial cells in alveoli. What kind of epithelia are these two cell types?

Back 12

Type 1: Alveolar cell for gas exchange (exchange epithelia)

Type II: Surfactant cells (ciliated epithelia)

Front 13

Trace a drop of blood through the pulmonary circulation from the Right ventricle to left atrium.

Back 13

RV -> PUlmonary trunk -> Pulmonary arteries -> lung capillaries -> Pulmonary veins -> LA

Front 14

Compare pulmonary blood flow, blood pressure, and capillary filtration to that of the systemic circuit.

Back 14

Blood flow: Rate is much higher than the rate in other tissues because lungs receive entire cardiac output of the right ventricle
BP: Low; 25/8 mm Hg, because of low resistance (shorter total length of pulmonary blood vessels and large cross-sectional area of pulmonary arterioles )
Capillary filtration: LOw because of low mean blood pressure

Front 15

Describe the association of the alveoli and the circulatory system.

Back 15

Very close; blood vessels fill 80-90% of space between alveoli, forming continous sheet of blood in close contact -> rapid gas exchange

Front 16

List the 4 integrated processes of external respiration (3 exchanges and 1 transport).

Back 16

1: Atmosphere to lung (ventilation)
2: Lung to blood
3: Transport of gases in the blood
4: Blood to cells

Front 17

What thoracic structures are not contained in the sacs?

Back 17

?

Front 18

Distinguish between atmospheric pressure and partial pressure.

Back 18

Partial pressure: pressure of a single gas

Patm x Percent of gas in the atmosphere

Front 19

Distinguish between lung volumes and lung capacities.

Back 19

Lung volumes:
1) Tidal volume (insp - exp)
2) Inspiratory reserve volume (additional volume you can inspire to full capacity (above tidal volume)
3) expiratory reserve volume: amount of air forcefully expired after tidal volume
4) residual volume: amount that you cannot expire out

Lung capacities: sum of 2 ore more lung volumes
Vital capcity: sum of inspiratory reserve volume, tidal volume, expiratory reserve volume, and residual volume = Total lung capacity

Or inspiratory capacity: inspiratory reserve volume + tidal volume

Functional residual capacity: expiratory reserve volume + residual volume

Front 20

What is inspiration and expiration?

Back 20

Inspiration: movement of air in the lungs

Expiration: movement of air out of lungs

Front 21

What is active vs. passive expiration?

Back 21

Passive: Expiration during quiet breathing involves passive elastic recoil rather than active muscle contraction

Active expiration: voluntary exhalations and when ventilation exceeds 30-40 breaths per minute

Front 22

What is total pulmonary ventilation and alveolar ventilation?

Back 22

Total pulmonary ventilation: volume of air moved into and out of the lungs each minute

breaths/min x tidal volume = total pulmonary ventilation

MINUTE VOLUME




Alveolar ventilation: amount of fresh air that reaches the alveoli each minute

Alveolar ventilation = ventilation rate x (tidal volume - dead space)

Front 23

What is restrictive and obstructive lung disease?

Back 23

Obstructive: Diseases in which air flow is diminished because of increased airway resistance

Restrictive: Decrease in lung compliance, because more work must be expanded to stretch a stiff lung; like fibrotic lung diseases

Front 24

What is hyperventilation and hyperpnea?

Back 24

Hyperventilation: Alveolar ventilation increases above normal levels (BUT NOT INCREASED METABOLISM -> like emotional hyperventilation, or blowing up a balloon)

Hyperpnea: Increased respiratory rate and or volume in response to increased metabolism, like exercise

Front 25

What is anatomic dead space and physiological dead space?

Back 25

Anatomic dead space: some air that enters the respiratory system does not reach the alveoli because some remains in trachea and bronchi; do not exchange gases with the blood

Physiological dead space: atm pressure is the same, not put into the body

Front 26

How does increasing water vapor pressure in a mixture of gases affect the concentration of those gases if nothing else changes?

Back 26

Decreases everything else's Partial pressure

Front 27

In which air passage(s) of the respiratory system is resistance to flow (normally) greatest?

Back 27

Trachea and bronchi (unless there is bronchoconstriction)

Front 28

At what point in a respiratory cycle is intrapleural pressure greatest? least? equal to atmospheric pressure?

Back 28

Greatest at the end of expiration and lowest at end of inspiration

Never equal to atmospheric pressure

Front 29

What is the role of surfactant in the alveoli? What happens if it is lacking?

Back 29

Surfactant: Reduces surface tension - if it is lacking, then takes more work to expand the lungs and alveoli

Front 30

What local factors influence resistance in the bronchioles? In the pulmonary arterioles?

Back 30

Bronchioles: Parasymp, symp, CO2

Pulmonary arterioles: decreased O2 around alveoli constricts alveoli, diverting blood to better ventilated alveoli

Front 31

Define hematocrit.

Back 31

Ratio of red blood cells to paslma indicated by hemotcrit and expressed as a percentage of the total blood volume

Front 32

Describe the structure and contents of the mature RBC.

Back 32

Structure: No nucleus, biconcave disks, filled with enzymes and hemoglobin, no mitochondria (use glycolysis), no ER, flexible, modify in response to osmotic changes in the blood.

Front 33

How is the lack of a nucleus related to the short life span of a RBC?

Back 33

They can't make new enzymes and renew membrane components, so they lose flexibility and are more likely to rupture.

Front 34

Why does the erythryocyte need to be flexible?

Back 34

To respond to osmotic changes

To squeeze through narrow capillaries of the circulation

Front 35

Describe or draw the structure of hemoglobin.

Back 35

Tetramer with 4 globins centered on a heme (iron) group.

Front 36

Why must we have adequate iron in the diet to make hemoglobin?

Back 36

Iron: part of hemoglobin

Front 37

what is the average life span of an RBC?

Back 37

120 +/- 20 days

Front 38

How are old RBCs destroyed and what happens to the RBC components?

Back 38

They are destroyed by rupturing as they try to squeeze through narrow capillaries, or are engulfed by scavenging macrophages

Many components are recycled: like amino acids from globin chains, iron

Front 39

What is the relationship between heme, bilirubin, and bile?

Back 39

Spleen and liver convert remnants of heme groups to a colored pigment called bilirubin. Bilirubin is carried by plasma albumin to the liver, where it is metabolized and incoprorated into a secretion called bile. Then bile is secreted into the digestive tract, and it leaves body in feces

Front 40

What is relative polycythemia?

Back 40

Person's RBC count is normal, but hematocrit is elevated because of low plasma volume (DEHYDRATION)

Front 41

By what mechanism do gases move between the alveoli and the plasma?

Back 41

simple diffusion

Front 42

List the 4 rules for diffusion of gases.

Back 42

Diffusion rate is proportional to surface area x concentration gradient x membrane permeability / membrane thickness

Most important: concentration gradient

Front 43

Why do respiratory physiologists commonly use partial pressures to express gas concentrations in solution?

Back 43

Allows direct comparison with partial pressure of the gases in the air, which is important for establishing whether there is a concentration gradient between the alveoli and the blood.

Front 44

When a gas is placed in contact with a liquid, what 3 factors determine how much gas will dissolve in the liquid?

Back 44

1) Pressure gradient of the gas
2) Solubility of the gas in the liquid
3) Temperature

Front 45

Which is more soluble in body fluids: oxygen or CO2?

Back 45

Co2

Front 46

Fill in the "Normal" values for the following partial pressures in a person at sea level:

Back 46

PO2: Alveoli: 100
Arterial blood: 95
Resting cells: 40
Venous blood: 40

PCO2:
Alveoli: 40
Arterial blood: 40
Resting cells: 46
Venous blood: 46

Front 47

Define hypoxia and hypercapnia.

Back 47

Hypoxia: a state of too little oxygen
Hypercapnia: doesn't always go with hypoxia, but elevated concentrations of carbon dioxide

SIGNS

Front 48

List 4 pathological changes in the alveolar-blood exchange surface that result in low arterial content.

Back 48

Emphysema: destruction of alveoli means less surface area for gas exchange.

Fibrotic lung diesease: thickened alveolar membrane slows gas exchange, and loss of compliance may decrease alveolar ventilation.

Pulmonary edema: FLuid in interstitial space increases diffusion distance; Arterial PCO2 may be normal due to higher CO2 solubility in water.

Asthma: Increased airway resistance decreases alveolar ventilation

Front 49

List 2 main reasons alveolar PO2 may be lower than normal

Back 49

Altitude and alveolar ventilation problems (like hypoventilation, like decreases compliance, increased airway resistance)

Front 50

The more soluble a gas is in a particular liquid, the ___ the parital pressure required to force the gas into solution.

Back 50

LOWER

Front 51

What 2 cell layers must gases cross to go from the alveoli to the plasma?

Back 51

Alveolar epithelium and capillary endothelial cells

Front 52

How much of the alveolar epithelium must be incapacitated before arterial PO2 drops?

Back 52

1/3

Front 53

What is pulmonary edema and how does it alter gas exchange?

Back 53

Fluid in interstitial space increases diffusion distance

Front 54

List 2 ways that gases are transported in the blood

Back 54

Dissolved in plasma or bound to hemoglobin

Front 55

__ % of oxygen in a given volume of blood will be carried bound to hemoglobin.

Back 55

98

Front 56

The amount of O2 bound to Hb depends primarily on what 2 factors?

Back 56

PO2 of plasma

Total number of binding sites

Front 57

What is the 'corpuscle' in the term mean corpuscular Hb?

Back 57

cell
amount of hemoglobin per RBC

Front 58

Describe the differences between adult and fetal hemoglobin.

Back 58

Adult: two alpha, two beta chains
Fetus: different isoform of hemoglobin, two gamma chains, two alpha chains; can get more O2 from maternal blood

Front 59

Explain how oxygen-hemoglobin binding obeys the law of mass action.

Back 59

Hb + O2 -> <- HbO2

As Hb goes up, HbO2 goes up

Front 60

As dissolved O2 diffuses into RBCs, what happens to the PO2 of the surrounding plasma?

Back 60

Lowers Po2, causing more O2 from alveoli to flow in

Front 61

In the oxyhemoglobin dissociation curve, the ___ determines the ___.

Back 61

PO2 determines percent saturation of Hb.

Front 62

Below PO2 of 60 mm Hg, where the curve is steeper, small changes in PO2 cause relatively __ releases of O2 from hemoglobin

Back 62

Large

Front 63

An increase in pH ___ hemoglobin's affinity for O2.

Back 63

increases

Front 64

An increase in temperature ___ hemoglobin's affinity for O2.

Back 64

decreases

Front 65

An increase in PCO2 ___ hemoglobin's affinity for O2.

Back 65

decrease

Front 66

The metabolite 2,3 DPG ___ hemoglobin's affinity for O2. What triggers an increase in 2,3 DPG?

Back 66

decreases; an increases in 2,3 DPG = high altitude, anemia

Front 67

FEtal Hb has an ___ affinity for oxygen.

Back 67

Increased

Front 68

A left shift in the curve indicates ___ binding affinity.

Back 68

Increased

Front 69

A right shift in the curve indicates ___ binding affinity.

Back 69

Decreased

Front 70

Why is it important that Co2 be removed from the body?

Back 70

Hypercapnia causes pH disturbance, which can denature proteins

also depress CNS function, causing confusion, coma or even death. For these reasons, CO2 is potentially toxic waste product that must be removed by the lungs

Front 71

List the three ways CO2 is transported in the blood.

Back 71

1) Dissolved in blood
2) RBC: converted to bicarbonate
3) RBC: bound to hemoglobin

Front 72

Write the equation, including the enzyme, in which Co2 is converted into bicarbonate ion and H+.

Back 72

CO2 + H2O -> carbonic anhydrase <- H2CO3 -> <- H+ + HCO3 –

Front 73

What 2 purposes does does the conversion of CO2 to HCO3- serve?

Back 73

1) provides additional means of CO2 transport from cells to lungs

2) HCO3- acts as a buffer for metabolic acids and stabilizes body pH

Front 74

What is the chloride shift?

Back 74

Transport process that exchanges HCo3- for Cl- that remove free H+ and HCO3-. The transfer of HCO3- into the plasma makes the buffer available to moderate pH

Front 75

What is a buffer?

Back 75

moderate pH changes caused by production of metabolic acids.

Front 76

Compare the rhythmicity and control of breathing to that of the heartbeat.

Back 76

Both rhythmic

Yet skeletal muscles (unlike autorhythmic cardiac muscles) are not able to contract spontaneously, but must be inititaed by somatic motor neurons, controlled by the CNS

Contraction of diaphragm and other muscles initiated by spontaneously firing network of neurons in the brain stem

Input by chemoreceptors for CO2, O2, and H+

Front 77

Compare the types of efferent neurons leaving the respiratory control center and the CV control center.

Back 77

Efferent neurons leaving respiratory control center = somatic motor neurons (inspiration + expiration)

Front 78

What role do each of the following play in the control of breathing?
a) medulla oblongata:
b) pons:
c) cerebrum:

Back 78

Medulla oblongata: respiratory neurons in the medulla control inspiratory and expiratory muscles

Pons: Neurons in the pons integrate sensory information and interact with medullary neurons to influence ventilation

Cerebrum: spontaneously discharging neurons and various chemoreceptor and mechanoreceptor-linked reflexes and higher brain centers

Front 79

Describe neural control of quiet respiration.

Back 79

18.17

Sensory input from mechanical and chemosensory neurons -> Nucleus tractus solitarus in pons (which contains dorsal respiratory group) -> controls muscles of inspiration, diaphragm, intercostal nerves to the intercostal muscles

Dorsal respiratory group -> respiratory neurons -> initiation and termination of inspiration -> pontine respiratory groups

Ventral respiratory group - basic pacemaker for respiratory rhythm, keep airways open for breathing

Ramping up, positive feedback loop up until the end of inspiration; then shut off and elastic recoil of inspiratory muscles and lung

VRG - inactive during quiet breathing until activated during forced breathing, activate internal intercostal and abdominal muscles

Front 80

List the location and chemical factor(s) monitored by each group of respiratory chemoreceptors.

Back 80

Peripheral chemoreceptors - carotid and aortic arteries near baroreceptors (change BP) sense changes in the PO2, pH, PCO2 of the plasma

Central chemoreceptors - in brain, respond to changes in concentration of CO2 in the cerebrospinal fluid; on ventral surface of medulla, close to neurons involved in respiratory control

Front 81

Explain the strategic significance of location of chemoreceptors.

Back 81

??
Maybe, that inspiration and expiration continuously by sensory input

In the carotid and aortic bodies, neurotransmitters initiate action potentials in sensory neurons leading to the brain stem respiratory networks, signaling them to increase ventilation

Front 82

Using the oxyhemoglobin dissocation curve in FIg. 18-9, explain the adaptive significance of the fact that the peripheral chemoreceptors do not respond to decrease in PO2 until PO2 drops below 60 mm Hg.

Back 82

B/c until 60 mm Hg, not really big changes in hemoglobin saturation

Front 83

An increase in PCO2 will trigger an __ in ventilation.

Back 83

Increase

Front 84

If PCO2 is chronically elevated (chronic hypercapnia) and hypoxia, is CO2 the primary chemical drive for ventilation? Explain.

Back 84

No, ventilation falls back toward normal rates as the chemoreceptor response adapts to low CO2...UNLESS there is a low arterial PO2 that remains intact...bc then low PO2 becomes the primary chemical stimulus for ventilation

Front 85

Write the reflex response to an inhaled irritant.

Back 85

write

Front 86

Give 2 examples of how higher brain centers can alter ventilation.

Back 86

1) Voluntary control of ventilation (holding breath) - but overriden by elevated PCO2 and cerebrospinal fluid activates chemoreceptor reflex

2) Limbic system (emotional and autonomic activities of fear and excitement) - neural pathway goes directly to somatic motor neurons, bypass control network in brain stem