EXAM 3: SEC2/Breathing

Question 1

Resp system functions

Answer 1

• bring atmospheric air into body and provide opportunity for diffusion of O2 and CO2 across resp. membrane
• blood carries O2 to tissues and CO2 away from

Question 2

Specialized Functions of Resp

Answer 2

• controlled ventilatory movements with fine control of oval muscles allow for taling
• mucociliary lining of conduction system helps prevent harmful matter into body and infectious organism
• endothelial lining activates/deactivates certain chemical messengers
• pulmonary capillary bed traps emboli from legs or other regions may prevent clots from reaching brain and heart
• diaphragm is primary muscle for quiet breathing

Question 3

Airway in order

Answer 3

• trachea
• bronchi
• bronchioles
• terminal bronchiolea
• resp bronchioles
• alveolar ducts
• alveolar sacs

Question 4

Blood

Answer 4

• pulmonary artery and branches = deoxygenated
• pulm arteries = deoxygenated
• pulm veins = oxygenated
• systemic arteries = oxygenated
• systemic veins = deoxygenated

Question 5

Lungs

Answer 5

• pleura membrane protects
• intrapleura fluid inbetween
• lungs not symmetrical
• left lung = 2 lobes
• right lung = 3 lobes

Question 6

Ventilation

Answer 6

• purpose = bring ambient air into close contact with pulonary capillary blood to exchange O2/CO2
• flow through tubule structures is directly proportional to the pressure difference to the ends of the tubes and inversely proportional to the resistance of flow from radi and length of tubes
• when atmo pressure is greater than alveolar pressure, air flows into lungs
• intrapleural pressure always = 3mmHg less than atmospheric pressure

Question 7

Ventilation Equation

Answer 7

(Alveolar pressure - atmospheric pressure) / resistance to airflow
= force promoting air flow
- 1 mmHg is all needed to move normal breath

Question 8

Events of Inspiration

Answer 8

• diaphragm and inspiratory inercoastals contract
• thorax expands
• interpulmonary pressure becomes more subatmospheric
• increase transpulmonary pressure
• lungs expand
• alveolar pressure becomes subatmospheric
• air flows into alveoli
• *BOYLE’S LAW**

Question 9

Lung Compliance

Answer 9

• measure of stiffness of the lung
• compliance is the difference in lung volume/ transpulmonary pressure difference
• as trasnpulmonary pressure increases, lung pressure increases
• increase compliance = lung is less stiff = easier to inflate
• if decrease compliance, takes greater change in pressure

Question 10

Spirometer

Answer 10

• measures breathing
• nose clip
• breath normal, then big in and big out
• tidal volume = 500 ml in average person at rest
• dead space = air that does not participate in gas exchange

Question 11

Gas exchange and transport

Answer 11

• O2 moves from alveolar gas to capillary down concentration gradient
• CO2 moves from capillary blood into alveolar gas down its concentration gradient
• gas exchange ratio 200/250 = 0.8

Question 12

Partial Pressures of Gas

Answer 12

• diffuse capacity of the lung for CO2 is higher than for O2, so smaller partial pressure is enough

Question 13

Gas Exchange

Answer 13

• as blood passes along pulmonary capillary, PO2 rises until is same as alveolar PO2
• rises pretty rapidly
• usually reaches alveolar PO2 1/4 way through capillary
• systemic venous PO2 is starting point because it is what is ended within systemic circulation and therefore what it starts with in the pulmonary system
• blood flow and ventilation needs to match to keep correct amounts of air/O2 in the body to avoid too much CO2
• O2 is transported via blood bound to hemoglobin
• O2 atoms bind reversibly to iron

Question 14

Venous pressures

Answer 14

• PO2 = 40 mmHg

- PCO2 = 46 mmHg

Question 15

Arterial pressures

Answer 15

• PO2 = 100 mmHg

- PCO2 = 40 mmHg

Question 16

Alvoli pressures

Answer 16

• PO2 = 105 mmHg

- PCO2 = 40 mmHg

Question 17

Atmospheric pressures

Answer 17

• PO2 = 160 mmHg

- PCO2 = 0.3 mmHg

Question 18

Transport of O2

Answer 18

• hemoglobin has 4 groups –> 2 alpha/2beta
• normal hemoglobin molecule can bind 4 molecules of O2
• amount of O2 bound is dependent on partial pressure
• increase partial pressure = greater binding sites for O2 = greater percent saturation
• 1.34 ml O2 per gram of hemoglobin
• total content O2 blood = sum dissolved O2 content and hemoglobin bound O2 content
• 25% of O2 in hemoglobin delivered to the tissues in healthy subject at rest
• up to 75-80% can be delivered if need by
• systemic venous PO2 = 40mmHg
• systemic arterial PO2 = 100 mmHg

Question 19

Effects on hemoglobin saturation

Answer 19

• increase concentration of 23DPG decreases O2 affinity of hemoglobin and shifts curve to the right
• increase temperature = decrease O2 affinity = curve to right
• increase acidity = decrease O2 affinity = curve shifts to right
• facilitating O2 release to tissues of body
• increase CO2 by RBC facilitates release O2 to body

Question 20

Neural generation of Rhythmical breathing

Answer 20

• an OD of morphine, barbituates, or alcohol suppresses the neurons in the ventral resp group and stops respiration
• regions in CNS regulate breathing
• in medella: 2 main components DRG (dorsal resp. group) and VRG (ventral resp group)
• DRG fires during inspiration stimulating diapragm
• VRG fires in both inspiration and expiration
• pons provides input to respiratory center

Question 21

Peripheral Chemoreceptors

Answer 21

• sensory feedback related to level of ventilation is provided by chemoreceptors
• peripheral receptors deal with PCO2
• hypoxcemia is low arterial CPO2
• peripheral chemoreceptors are in aortic bodies and carotid bodies

Question 22

Hyperventilation

Answer 22

• can happen at high altitude
• occurs when decrease PO2, decrease alveolar PO2, decrease PO2 therefore increase chemoreceptor firingl, increase resp muscle contractions and therefore increase ventilation
• big contributor increase alveolar PCO2
• increase ventilation also increase with acid (lactic acid) to help decrease PPCO2 (called metabolic acidosis)

Question 23

Exercise

Answer 23

• ventilation increases and decreases abruptly at start and finish of exercise
• arterial PO2 and PCO2 and H+ don’t change much
• hormones may have influence ventilation

Question 24

Arterial Hypoxemia

Answer 24

• respiratory disease

- low arterial PO2

Question 25

5 main causes of hypoxemia

Answer 25

• ambient hypoxia. low O2 in atmosphere
• alveolar hypoventilation b/c takes in less O2
• diffusion impairment because equilibrium may never be achieved
• physiologic shunt. blood doesn’t pick up O2
• ventilation/perfusion mismatching b/c blood w/low PO2 is added to blood w/well ventilation, loweing overall

Question 26

Hypoxia

Answer 26

• inadquete O2 delivery to tissues

- pathology of emphysema is major cause of hypoxia

Question 27

Anemic Hypoxia

Answer 27

• poor O2 delivery b/c of too few RBCs or abnormal hemoglobin

Question 28

Ischemic Hypoxia

Answer 28

• blood circulation is impaired

Question 29

Histotoxic Hypoxia

Answer 29

• body’s cells are unable to use 2 (cyanide causes)

Question 30

Hypoxemic Hypoxia

Answer 30

• reduced arterial O2 (can be cause by lack of oxygenated air, pulmonary problems, lack of ventilation perfusion coupling)

Question 31

Carbon Monoxide Poisoning

Answer 31

• type of a hypoxemic hypoxia
• leading cause of death from fire
• CO = odorless, colorless gas competes with oxygen for binding sites and has 200X greater affinity for hemoglobin than O2
• symptoms: confusion, resp distress, skin becomes red
• no cyanosis is detectable
• treated with hyperbarics or 100% O2

Question 32

Functions of Respiratory System

Answer 32

• provides O2
• eliminates CO2
• regulates blood’s hydrogen ion concentration (pH) w/kidney
• forms speech sounds (phonation)
• defends against microbes
• influences aarterial concentrations of cemical messengers by removing some pulmonary capillary blood and producing and adding others to this blood
• traps and dissolves blood clots arising from systemic veins such as those in legs