Overview and Ventilation of Lungs

Question 1

External respiration

Answer 1

Transport of O2 and CO2 between the environment and tissues

Question 2

Internal Respiration

Answer 2

Oxidative phosphorylation (using oxygen to generate ATP in mitochondria)
Takes place in the tissues

Question 3

What are the 4 processes involved in respiration?

Answer 3

1. Ventilation (O2 in, CO2 out)
2. Diffusion @ lung (alveoli)
3. Gas transport in blood
4. Diffusion @ tissue level

Question 4

What does diffusion in the lung involve?

Answer 4

Occurs in the alveoli
O2 diffuses and is taken up by BVs

Question 5

What does diffusion @ tissue level involve?

Answer 5

CO2 taken back to lungs for ventilation
O2 utilized by tissues

Question 6

Why is the respiratory system important?

Answer 6

One of the vital signs to be assessed in TPR
Route of entry
Route for inhalant
Involved in vocalization, defense and metabolism

Question 7

Nostrils (nares)

Answer 7

Airways start with nares
Paired external openings
Most pliable and dilatable in horse
Most rigid in pig

Question 8

Horses are ____________ breathers

Answer 8

Obligate nasal

Question 9

Upper airways

Answer 9

Portion that extends fro the nares or mouth to and including the larynx

Question 10

Lower airways

Answer 10

Extends from the subglottis (trachea) to and including the terminal bronchioles

Question 11

Generations

Answer 11

Progressive branchings made by airways
Alveoli start to bud off respiratory bronchioles around generation 17

Question 12

Species generation differences

Answer 12

Humans: 0-26
Horses: 43

Question 13

What happens when generation number increases?

Answer 13

Amount of cilia, # of mucus secreting cells, submucosal glands and cartilages decrease

Question 14

Cartilage in the airways

Answer 14

Cartilage maintained until several branching from trachea (10th gen.), then referred to as Bronchi
Prevent airways from collapsing
Bronchioles are cartilage free

Question 15

Alveoli air spaces

Answer 15

Gas exchange takes place
Density increases with generation number
Alveolar ducts terminate as blind alveolar sacs (gen 26)

Question 16

Terminal respiratory unit

Answer 16

Aggregation of airways arising from a terminal bronchiole along with associated blood and lymphatic vessels

Question 17

Respiratory membrane makeup (out to in)

Answer 17

Alveolar fluid (with surfactant)
Alveolar epith.
BM of alveolar epith.
Interstitial space
BM of capillary endothelium
Capillary endothelium
Diffusion of CO2
Diffusion of O2
RBC

Question 18

Respiratory membrane

Answer 18

Blood-air barrier
Gas diffusion compromised if this compromised

Question 19

What does O2 consumption depend on?

Answer 19

The level activity (metabolic rate)
O2 requirements may increase up to 30x during strenuous exercise

Question 20

Which species has a greater O2 demand?

Answer 20

Horse and dog

Question 21

Basal (resting metabolism)

Answer 21

Smaller species consume more O2 per Kg of bodyweight than do larger species

Question 22

Respiratory cycle

Answer 22

Consists of an inspiratory phase followed by an expiratory phase

Question 23

Inspiration

Answer 23

Chest cavity increase and abdominal structures pushed down
Increased abdominal pressure and volume of the thoracic cavity
Decreased thoracic cavity, alveolar/pulmonary and intrapleural pressure

Question 24

Expiration

Answer 24

Opposite of inspiration
Passive process
Relaxation of muscles, recoil of lungs, air outflow

Question 25

Ventilation

Answer 25

Movement of air into and out of the lungs Direction of movement is affected by relationship between intrapulmonary and atmospheric pressures

Question 26

Inhalation and exhalation pressure vs. outside environment

Answer 26

Inhalation: P inside < P outside Exhalation: P inside > P outside Rest (no flow): P inside = P outside

Question 27

Intrapleaural space

Answer 27

Sealed cavity Pull-on lungs (inflate) V is inversely proportional to P

Question 28

Boyle's Law

Answer 28

In a closed container: V = K/P PV= K *K=constant*

Question 29

What pressures are involved in ventilation?

Answer 29

PB= barometric (atmospheric) PA = alveolar (pulmonary) PIP = intrapleural (PPL)

Question 30

Intrapleural pressure in always below ________

Answer 30

Atmospheric pressure (negative pressure)

Question 31

Transpulmonary pressure (PTP)

Answer 31

PA- PIP = PTP

Question 32

How are the pressures at rest?

Answer 32

End of expiration PA= PB

Question 33

Pressures during inspiration

Answer 33

Increase in size of chest wall: Decreases PIP, decline in PA and subsequent airflow into the lungs

Question 34

Where would PIP be highest in domestic animals

Answer 34

Ventral aspect of the lungs (close to sternum)

Question 35

What major muscles are involved in inspiration?

Answer 35

Diaphragm (phrenic n.) and intercostals (internal and external)

Question 36

What are the secondary muscles involved in inspiration?

Answer 36

Sternocleidomastroid Neck and back muscles Scalenes

Question 37

T/F: There are no primary muscles of expiration

Answer 37

TRUE *passive process*

Question 38

What muscles are involved in forced expiration? (asthma, exercise)

Answer 38

Abdominal muscles and intercostals

Question 39

How are volume and pressure determined?

Answer 39

Using Spirometry (vol) and plethysmographs (P)

Question 40

Tidal volume (TV)

Answer 40

Volume of each breath (rest level breathing)

Question 41

Inspiratory Reserve Volume (IRV)

Answer 41

Extra air you breathe in after inhalation

Question 42

Residual volume (RV)

Answer 42

Volume of air left in lungs after maximum exhalation

Question 43

Expiratory residual volume (ERV)`

Answer 43

Volume of air you can further exhale after exhalation

Question 44

Vital Capacity (VC)

Answer 44

ERV + TV + IRV (maximum achievable TV)

Question 44

Inspiratory capacity (IC)

Answer 44

TV + IRV

Question 45

Total lung capacity (TLC)

Answer 45

@ maximum inhalation, max volume of air RV + ERV + TV + IRV

Question 46

Functional residual capacity (FRC)

Answer 46

Volume remaining in lungs after exhalation ERV + RV

Question 47

Forced expiratory volume in 1 second (FEV1)

Answer 47

Should be 80% of vital capacity in a healthy adult

Question 48

Dead space

Answer 48

Where no gas exchange takes place Anatomic + Alveolar dead space= physiologic dead space DV= dead space air

Question 49

Anatomic dead space

Answer 49

Conductive airways nares to terminal bronchioles

Question 50

Alveolar dead space

Answer 50

Poorly perfused alveoli, limited to no exchange

Question 51

Respiratory frequency (f)

Answer 51

Number of breaths per minute

Question 52

Minute ventilation

Answer 52

VE= TV x f = (AV + DV) x f

Question 53

What happens in deadspace?

Answer 53

Air is cleaned, moistened and warmed

Question 54

Dead space/ tidal volume ratio

Answer 54

DV/TV: the fraction of each breath ventilating in dead space 30% in dogs 50-75% in cattle and horse

Question 55

What is tidal volume and f responsible for?

Answer 55

Altering the amount of air ventilating the alveoli during exercise and thermoregulation

Question 56

Heat stress

Answer 56

Dogs (panting) small increase in TC, f and deadspace ventilation, evaporation, and heat loss Large animals: Increase in f, DS ventilation and heat loss present

Question 57

Cold stress

Answer 57

Increase metabolism (O2 consumption, CO2 production that needs to be eliminated) Increased alveolar ventilation (increase TV) Decrease in DS ventilation and f