Circulatory Response to Exercise Lecture 3/Respiration During Exercise Lecture 1

the signal to turn on CV system at onset of exercise

central command

CC refers to ____ _____ _____ within the higher brain centers

motor signal development

CC Theory argues that initial CV changes at beginning of exercise are due to

centrally generated CV motor signals

CV activity is regulated by afferent feedback from:

heart baroreceptors

heart mechanoreceptors

muscle mechanoreceptors

muscle chemoreceptors

located within carotid arteries and aortic arch

heart mechanoreceptors

sensitive to increases in muscle metabolites (K+ and La-)

muscle chemoreceptors

muscle spindles and GTO

sensitive to the force and speed of muscular movement

muscle mechanoreceptors

located within carotid arteries and aortic arch

sensitive to changes in arterial blood pressure

heart baroreceptors

important chronic adaptations to exercise

increase plasma volume

increase red blood cells

increase total blood volume

increase end diastolic dimensions and ventricular volumes

increase maximal stroke volume

increase maximal cardiac output

decrease systolic and diastolic blood pressure

two definitions of respiration in physiology

pulmonary respiration

cellular respiration

ventilation (breathing)

exchange of gases in lungs

pulmonary respiration

relates to O2 utilization and CO2 production by the tissues

cellular respiration

primary purpose of the lungs

provide a means of gas exchange between external environment and cells of the body

lungs bring O2 into the body when a person

inhales

lungs eliminate CO2 from the body when a person

exhales

exchange of O2 and CO2 between the lung and blood occurs as a result of

ventilation and diffusion

mechanical process of moving air into and out of lungs

ventilation

random movement of molecules from an area of high concentration to low concentration

diffusion

four functions of the lungs

ventilation

alveolar gas exchange

circulatory (gas) transport

systemic gas exchange

movement of respiratory gases between atmosphere and gas exchange region of lungs

ventilation

movement of respiratory gases between alveolar region and blood

alveolar gas exchange

transport of respiratory gasses in blood between lungs to cells of body

circulatory (gas) exchange

movement of respiratory gases from blood inset cells of body

systemic gas exchange

since O2 tension in the lungs is greater than in the blood

O2 moves from the lungs into the blood

diffusion in the respiratory system occurs rapidly because

large surface area within the lungs

short diffusion distance between blood and gas in the lungs

right and left lungs are enclosed by a set of membranes called

pleura

adheres to outer surface of lung

visceral pleura

lines thoracic walls and diaphragm

parietal pleura

both pleura are separated by

thin layer of fluid that acts as a lubricant

upper tract

nose

nasal cavity

pharynx

lower tract

larynx

trachea

bronchi

lungs

2 functional zones of respiratory system

conducting zone

respiratory zone

conducting zone consists of

trachea

bronchial tree

bronchioles

conducting zone function

passageway for air

humidifies and filters air

air is warm and saturated with water vapor

conducting zone is also known as

anatomical dead space

conduction zone accounts for ______ ml of the normal 500 mL tidal volume

150

respiratory zone consists of

respiratory bronchioles

alveolar ducts

alveolar sacs

respiratory zone accounts for _____ mL of 500 mL tidal volume

350

_____ ______ occurs in alveoli

gas exchange

average diameter of alveoli

0.25 mm

respiratory has a _____ surface area for diffusion

large

average surface area of alveoli

70 sq meters

movement of air from environment to lungs occurs via

bulk flow

movement of molecules along a passageway due to a pressure difference between 2 ends of the passageway

bulk flow

most important muscle that controls breathing process

diaphragm

as diaphragm flattens...

causes the chest to expand

air sucked into lungs

when diaphragm relaxes

chest collapses

air in lungs forced out

during normal, quiet breathing, diaphragm performs ____ of the work of inspiration

most

during exercise, ______ _____ assist inspiration

accessory muscles

accessory muscles that assist inspiration

SCM

scalenes

external intercostals

parasternal intercostals

pectoralis minor

diaphragm

during normal, quiet breathing, expiration is _____

passive (no muscular effort needed)

during exercise, expiration is ____

active

most important muscles for expiration

rectus abdominis

external obliques

internal obliques

transverse abdominis

internal intercostals

the movement of air into and from the lung by the process of bulk flow

ventilation

ventilation (VE) (L/min) =

frequency (br/min) x tidal volume (L)

property of being able to increase size of value with only small changes in pressure

compliance

pulmonary ventilation at rest:

f = 12

VT = 0.5

VE = 6

pulmonary ventilaiton at mild exercise

f = 32

VT = 2.25

VE = 72

pulmonary ventilation at maximal exercise

f = 48

VT = 3.33

VE = 160

volume of fresh air that reaches respiratory zone of lung where gas exchange occurs

alveolar ventilation

alveolar ventilation (VA) =

frequency (br/min) x (tidal volume - 0.15) (L)

the ______ the depth of breathing, the ____ impact the anatomical dead space has on alveolar ventilation

greater; less

effect of changes in breathing patterns on alveolar ventilation: shallow and rapid breathing

VT = 0.24

f = 25

VE = 6

VA = 2.25

effect of changes in breathing patterns on alveolar ventilation: normal resting breathing

VT = 0.5

f = 12

VE = 6

VA = 4.2

effect of changes in breathing patterns on alveolar ventilation: slow and deep breathing

VT = 1

f = 6

VE = 6

VA = 5.1

an increase in alveolar ventilation (at rest) resulting in hyperventilation will decrease arterial ______ and increase ____

PCO2

pH

volume of air inspired or expired during a normal inspiration or expiration

tidal volume

amount of air inspired forcefully after inspiration of normal tidal volume

inspiratory reserve volume

amount of air forcefully expired after expiration of normal tidal volume

expiratory reserve volume

volume of air remaining in respiratory passages and lungs after the most forceful expiration

residual volume

tidal volume plus inspiratory reserve volume

inspiratory capacity

expiratory reserve volume plus the residual volume

functional residual capacity

sum of inspiratory reserve volume, tidal volume, and expiratory reserve volume

vital capacity

sum of inspiratory and expiratory reserve volumes plus the tidal volume and residual volume

total lung capacity

total pressure of a gas mixture is equal to the sum of the pressures that each gas would exert independently in the mixture

dalton's law

PP

partial pressure

PP can be calculated by multiplying the fractional composition of the gas by the

barometric pressure

barometric pressure at sea level

760 mmHg

during respiration, three gases are exchanged between the atmosphere and the body:

O2 = 0.2093

CO2 = 0.0003

Nitrogen = 0.7904