week 9

Question 1

pulmonary ventilation refers to:

Answer 1

the mechanical mvmt of air in and out of the body

Question 2

what is eupnea and describe muscles involved

Answer 2

eupnea is quiet breathing

inspiration is active and expiration is passive

muscles involved are the diaphragm and the external intercostals

Question 3

what is hyperpnea and describe muscles involved

Answer 3

increased Ve that matches metabolic demands

Inspiration is active and expiration is also active

Muscles involved in inspiration: diaphragm, external intercostals, scalenes and sternocleidomastoid

Muscles involved in expiration: abdominals and internal intercostals

Question 4

What is minute ventilation

Answer 4

The total volume of air that we inspire or expire every minute - what we can easily measure

Question 5

Define tidal volume

Answer 5

The volume of each breath (VT)

Question 6

Define breathing frequency or respiratory rate

Answer 6

Number of breaths per min (fB)

Question 7

Define alveolar ventilation

Answer 7

Amount of air that reaches the alveoli and can participate in gas exchange - effective ventilation (what we care about)

Question 8

Define dead space (VD)

Answer 8

Portion of each breath that gets wasted

Question 9

Define anatomical dead space

Answer 9

Air that never reaches the alveoli

Always there

Assumed to be 150 mL

Question 10

Define physiological dead space

Answer 10

Air that never reaches the alveoli with no/poor perfusion (blood flow)

Question 11

What is the formula for calculating minute ventilation

Answer 11

VE = VT x fB

Question 12

What is the formula for alveolar ventilation

Answer 12

VA = (VT - VD (assumed 150 mL)) x FB

Question 13

Outline the three phases associated with the VE response to dynamic exercise

Answer 13

Phase 1: immediate increase - fast component ~ 10 s

Phase 2: exponential increase - slow component ~ 1 min (more at high intensity)

Phase 3: steady state - appropriate for MR unless intensity is too high to be supported aerobically - steady state never attained

VE plateaus within 1-2 mins

Question 14

Review pages 5 6 and 7 of respiratory I

Question 15

What are early VE responses driven by

Answer 15

VT and then FB

Question 16

What does reducing VD/VT mean

Answer 16

You have to move less air to meet gas exchange needs - saves energy

Question 17

Why is breathing tightly controlled

Answer 17

• to match metabolic demands (VO2 and VCO2)
• to maintain acid-base balance (pH)
• to clear airways
• to communicate (phonation + emotional expression)

Question 18

What is the term used for under ventilation

Answer 18

Hypoventilation

Insufficient supply
- can’t meet metabolic demands
- reduced energy capacity
- serious consequences - death blah

Insufficient clearance
- CO2 accumulates
- causes problems on its own

Question 19

What is the term used for over ventilation

Answer 19

Hyperventilation

Waste of energy
Slight oversupply of O2 (not harmful)
Excessive clearance of CO2:
- CO2 levels drop
- causes problems on its own

Question 20

Where is the central control of breathing and what triggers inspiration

Answer 20

In the brainstem - pons and medulla

Nerves trigger inspiration

Question 21

Describe volitional control of breathing

Answer 21

• how we can voluntarily override our breathing control centers
• involves higher brain centers - cerebral cortex

Question 22

Describe chemical control of breathing

Answer 22

Uses central chemoreceptors in the medulla and peripheral chemoreceptors in the aorta and carotid artery
- together, they sense CO2, pH, and O2 of arterial blood

Question 23

What is ventilation stimulated by

Answer 23

• increased CO2
• decreased pH -> increased H+
• decreased O2

Question 24

What is the influence of body temp on the breathing control centers

Answer 24

Temp directly excites the breathing control centers - increased VE

Question 25

What is the contribution of proprioceptors on the breathing control centers

Answer 25

Sensory input from muscles, joints and tendons provide input that the body is moving - increased VE

Question 26

What is the influence of higher centers on the breathing control center

Answer 26

Cortical control - includes volitional control - non-volitional influences include: - thinking about/planning/controlling mvmt - central command Hypothalamic control - strong emotion - perception of pain and intense effort

Question 27

describe what O2 and CO2 look like in the following conditions: 1. inspired air 2. alveolar air 3. arterial blood 4. venous blood

Answer 27

1. PIO2 and PICO2 2. PAO2 and PACO2 3. PaO2 and PaCO2 4. PVO2 and PVCO2

Question 28

in exercise induced hyperpnea, what factors are responsible for: 1. initial jump to phase I 2. gradual climb and settling in at steady state 3. ventilatory drift that happens after ~30 mins

Answer 28

1. brain involvement in generating mvmt (anticipatory response) 2. brain involvement in generating mvmt, mvmt of muscles and joints, perception of mvmt and effort 3. increased body temp

Question 29

what is the ACSM classification and what are its pros and cons

Answer 29

all possible intensities from rest to max divided into 5 categories pro: very simple to apply to anyone con: doesnt make much sense physiologically or metabolically

Question 30

define domains

Answer 30

domains (the categories) are defined by metabolic processes that occur at that intensity

Question 31

define boundaries

Answer 31

boundaries between domains are defined by physiological events - we figure out the lower/upper limits of each domain by determining the boundaries

Question 32

what do we determine boundaries/domains based on and what is a pro and a con of this

Answer 32

we determine boundaries and domains based on: HR, power, and speed pro: based on individual physiology rather than guesses con: technically demanding and resource intensive to determine

Question 33

what is determination useful for

Answer 33

1. assessing/monitoring subtle changes in fitness 2. determining precise training intensities to elicit specific metabolic adaptations 3. predicting endurance performance

Question 34

describe the extreme intensity domain

Answer 34

steady state: not attainable sustainability: less than 2 mins anaerobic contribution: significant fatigue mechanisms: accumulation of metabolites, central fatigue

Question 35

describe the severe intensity domain

Answer 35

steady state: not attainable sustainability: several minutes anaerobic contribution: substantial fatigue mechanisms: accumulation of metabolites, central fatigue example: VO2 max

Question 36

describe the heavy intensity domain

Answer 36

steady state: reached within 10-20 mins sustainability: multiple hours anaerobic contribution: obvious fatigue mechanisms: glycogen depletion, central fatigue example: maximum sustainable intensity

Question 37

describe the moderate intensity domain

Answer 37

steady state: reached within 2-3 mins sustainability: indefinitely anaerobic contribution: negligible fatigue mechanisms: central fatigue example: measurable anaerobiosis

Question 38

describe metabolic thresholds

Answer 38

they represent physiologically significant events 1st metabolic threshold - when anaerobic glycolysis rises above the baseline - boundary between moderate and heavy domains 2nd metabolic threshold - when the rate of anaerobic glycolysis makes exercise unsustainable - boundary between heavy/severe domains

Question 39

how can we identify thresholds

Answer 39

we can identify thresholds using data from incremental tests to maximum lactate data -> lactate thresholds (LT1/LT2) ventilatory data -> ventilatory thresholds (VT1/VT2)

Question 40

describe LT1

Answer 40

intensity where [La-] first increases more than or equal to 1 mmol/L above baseline - [La-] is now spilling into the blood because rate of La production exceeds rate of La clearance by the cell

Question 41

describe LT2

Answer 41

intensity where [La-] vs WL curve starts to increase more steeply - La is now accumulating in the blood because the rate of La production exceeds the rate of La clearance from the blood (skeletal muscle, heart, liver)