EXAM 2 Flashcards
_ is exemplified by:
- segmental anatomy
- pores between alveoli
- lobes
redundancy
- warm the air
- transport the air
- are dead space
- conduct gas conly
conducting zones
gas pressures equilibrate due to solubility and pressure differentials
Henry’s Law essentially
During exercise, _ due to:
- increase in breathing rate
- increase in breathing depth
Ve increases
_ is:
- airlessness
- why we move at night
atelectasis
_ is an example of restrictive pulmonary disease
asthma
Primary reason CO2 equilibrates so quickly is _
sollubility
Inspiration is always _
active
Expiration can be _
active and passive
an individual with cystic fibrosis is at greater risk for lung infection because _
the fluid layer is too high
_ increases with age due to loss of elasticity
residual volume (RV)
Functional Residual Capacity (FRC) is important because
maintains pressure for adequate gas exchange
Two types of ventilation are _
pulmonary and alveolar
_ increases with exercise due to:
- an increase in tidal volume
- an increase in depth
anatomic dead space
_ is:
- too much ventilation for the blood flow
- too little ventilation for the blood flow
- mismatch between ventilation and blood flow
physiologic dead space
partial pressures in the lung are
lower than the trachea
Two ways oxygen is carried in the blood _
- bound to hemoglobin
- bound to RBC
cardiac output at rest is typically _
4-6 L/min
The (a-v)O2 difference describes
tissue uptake of oxygen
A change in the shape of the hemoglobin molecule
Bohr effect essentially
_ increases with altitude
2,3-DPG
myoglobin does not have a Bohr effect because
myoglobin carries only one oxygen
- is a forced exhale against a closed glottis
- increases thoracic (chest pressure)
- reduces venous return
valsalva maneuver
Normal _ (healthy)
- is about 0.5 L
- is mostly fresh air
tidal volume
The physiologic dead space is problematic when it
is more than 60% of lung volume
The heart is a _
muscular organ
Functions of _ :
- transport O2 and CO2
- transport nutrients
- regulate temperature
cardiovascular (CV) system
The force generation by the right side of the heart is _ and if _
- less than the left
- it is less than the left the person is healthy
stimulation of the heart is conducted
via intercalated disks
Contraction of the _ is 3-15X longer than the contraction of skeletal muscle
heart
The electrical stimulus for the heart originates in the _
right atrium
The pause of the electrical flow in the AV node (Bundle of HIS) is to _ and _
- allow the atria to contract (atrial ejection)
- allow the ventricles to fill
The absolute refractory period in the heart
prevents the heart from contracting
The atria have a shorter refractory period than the ventricles. This then allows _
the atria to have a faster rate than the ventricles
Isovolumic (isovolumetric) contraction is that period of time in the cardiac cycle in which
- the atria are filling
- the ventricles are contracting
- the volume is unchanged in the ventricles
End systolic volume (ESV) is typically _ (at rest)
about 40-50 ml
When ejection fraction is 30% or less of total ejection the prognosis for life is _
not good
A normal cardiac cycle is best measured _
R to R
- the volume of blood in ventricles at the end of diastole
- end diastolic volume
preload
- the greater the stretch of the ventricle the more blood ejected
- the greater the EDV the greater the ejection
- the heart pumps what the heart gets
Frank-Starling Law (or mechanism)
The pressure needed to open the aortic valve
afterload
The inherent rhythmicity of the heart can be overridden by the _
cardiovascular control center (CVC)
sympathetic innervation of the heart leads to _ and _
- increased rate
- increased force of contraction
- innervates both the atria and the ventricles
- causes the heart to contract less forcefully
- causes the heart rate to slow
parasympathetic innervation of the heart
Peripheral input sends messages relating to _
- pressure
- tension
- movement
excess calcium causes _
spastic contractions of the heart
cortical input can impact the heart via _
emotions
During resistance training blood pressure _
Systolic BP and Diastolic BP increase
- is a measure of myocardial work
- is an index of relative cardiac work
- is used to monitor heart symptoms in the CVD population
The rate pressure product
The most important criteria for the CV system during exercise is _
maintain blood pressure
The trachea moves debris similarly to a _
blow gun
_ is matched to the volume of air demonstrated by submarine volume changes
volume in an alveoli
as you begin to inhale, the pressure in the alveoli is _
negative
Exhalation is _ at rest
passive
the surface area of alveoli is the size of _
a tennis court
when someone has restrictive lung disease (RLD) _ is restricted
inhalation
atria has thinner walls than ventricles because they _
- pump blood a shorter distance
- do not pump as much blood
- are primary reservoirs
- primary purpose is not pumping blood
The _ ventricle is thicker than the _ ventricle
Left is thicker than Right
after leaving the Bundle of HIS, the electrical signal travels down the _
RBB and LBB to the perkinjie fibers
depolarization of cardiac muscle is _
fast
_ goes up more during resistance training than it does during aerobic training
systolic blood pressure (SBP)
_ decreases to a similar degree as systolic blood pressure during an aerobic bout
diastolic blood pressure (DPB)
Blood pressure is higher for predominantly arm exercises than predominantly leg exercises because _, _ and, _
- smaller blood vessels in the arms
- greater peripheral resistance in the arms
- heart has to work harder
Blood pressure can be lower than pre-exercise for _ post an aerobic bout
2-3 hours
During an aerobic bout, the heart will use _ primarily for its energy source
lactate
_ input exerts lesser influence on blood flow during exercise than _ input
- parasympathetic
- sympathetic
as total peripheral resistance goes up, _ also increases
blood pressure
During exercise: at the _ there is significant _ in blood volume delivered to the working muscle
- local level
- increase
During exercise: at the _ there is NOT significant increase in the velocity of blood flow to the tissues
local level
Lung is a _ organ
- built similar to pyramids (apex at top, base at bottom, with segments)
- packaging problem (55% on R, 45% on L)
mechanical
Major lung properties _
- dry
- inflated
Gas exchange: O2 into the lungs and CO2 out
- works with circulatory system: transport gases through the body and back to the lungs
lung functions
Purpose of _
- prevent spread of infection
- prevent complete obstruction from an inflated foreign body
lung segments
segmental anatomy:
redundancy
Lobe segments ( _ total):
20 total
- upper
- middle
- lower
- process of moving and exchanging ambient air with air in the lungs
- air enters through nose and mouth, and flows through ventilatory system
- conducting zones
- transitional respiratory zones
pulmonary ventilation
_ zone
- air adjusts to body temperature, filtered and almost completely humidified
- includes: trachea, bronchi, bronchioles
- has cartilage, lower do not, interdependent
conducting zone
conducting zone also termed _ due to containing no alveoli
anatomic dead space
_ zones
- contains: bronchioles, alveolar ducts, alveoli
- occupies about 2.5-3L
- is the largest portion of total lung volume
transitional and respiratory zones
_ zone is where gas exchange occurs
respiratory zone
_ zone functions:
- air transport
- humidification
- warming
- particle filtration
- vocalization
- immunoglobulin secretion
conducting zone
_ zone functions:
- surfactant production (in alveolar endothelium)
- molecular activation and inactivation (in alveolar endothelium)
- blood clotting regulation
- endocrine function
respiratory zone
air is distributed in proportion to _
segmental volume
ventilation is matched to volume:
regional ventilation = regional volume
_ : branch point of the lungs
- bronchiole tree is not symmetrical
carina
food must pass from _ to _ and air from _ to _
- can be problem in old and young
- glottis defends the airway
- front to back
- back to front
_ : rigid, cartilaginous box
- narrowest part of the system
- “V” is front: vocal cords
- vocal cords move in synchrony with diaphragm
larynx
_ : ~vacuum hose
- posterior is muscle, anterior is cartilage rings
- muscle allows ability to cough
- posterior utilized to expel objects: blow gun/spit wad effect
trachea
_ : large, dome-shaped sheet of striated musculofibrous tissue
- primary ventilatory muscle which creates an airtight separation between abdominal and thoracic cavities
diaphragm
membrane is responsible for almost all respiratory muscles shortening and volume displacement
diaphragm
diaphragm _, _, and _
- contracts
- flattens
- and moves downward toward abdominal cavity (up to 10cm)
elongation and enlargement of chest cavity expands the air in the lungs _ decreases
intrapulmonic pressure (IP)
with a drop in intrapulmonic pressure (IP), pressure in lungs is _
lower than atmospheric pressure
degree to which lungs fill is determined by the _ of the inspiratory movement
magnitude
maximal activation of the inspiratory muscles in a healthy individual ranges from _
80-140 mm Hg
inspiration ends when _
thoracic cavity stops
(inspiration) stop in thoracic movement means there is a same pressure in lungs (IP) as _ pressure
ambient atmospheric
during exercise: a need for more efficient movements of the diaphragm, rib cages, and abdominal muscles
inspiration in exercise
during _, the saleni and external intercostal muscles contract, causing the ribs to rotate and lifting a handle up from a bucket
inspiration
Inspiration increases during exercise when the diaphragm _, ribs _, and sternum _
- this is an elaborate way of increasing the lateral and anterior-posterior diameter of the thorax
- diaphragm descends
- ribs upward
- sternum thrusts outward
Athletes bend forward at waist to _
- promotes flow flow back to heart
- minimizes antagonistic effect of gravity on the usual upward direction of inspiratory muscles
facilitate exhaustive breathing
2 factors of expiration:
- Natural recoil of the stretched lung tissue
- Relaxation of the inspiratory muscles
During expiration, ribs _, and diaphragm _
- ribs swing down (bucket handles)
- diaphragm rises toward the thoracic cavity
Expiration ends when compressive force of the expiratory musculature ends and intrapulmonic pressure (IP) _
decreases back down to atmospheric pressure
muscles of expiration
(intercostals are stabilization)
(usually passive)
- rectus abdominus
- obliques
- lats
chronic obstructive pulmonary disease
- mismatch between ventilation and perfusion
COPD
restrictive lung disease
- inhalation is restricted
- more work to breath
RLD
air moves across a _
pressure gradient
Flow in lungs is _, not turbulent, difficult to _
- swirly
- characterize the flow in upper airways
Flow in lungs - assume Ohms law:
Resistance (R) = change pressure/flow or flow = change in pressure/R
V = flow/area
velocity
- need low pressure for inspiration: 5 cm/H2O
- inhale pressure has capacity for 120 cm/H2O
- maximal inspiratory pressure (MIP) usually occurs at functional residual capacity (FRC), low lung volumes, usually about -80 to -100 cm/H2O
-MEP: occurs at high lung volumes, recoil of diaphragm (100-110 cm/H2O) - due to length tension relationship
velocity
Disease states: (obstructive airway disease)
greater pressure for adequate flow
Delta Vt/Delta pressure =
compliance
high compliance:
Emphysema
with increased pressure
- _ chest wall diameter
- _ abdominal space
- increase
- compress
alveoli are connected via smooth muscle and connective tissue: one opens, all open to _
prevent atelectasis
similar to flypaper, lubricates, and protects
- hydrates
- provides protective surface
- collect debris
mucosal clearance
Goblet cells secrete _
sticky, tenacious mucous
submucosal glands are _, makes islands
less sticky
debris is moved up on islands to carinas via _
- clean from periphery to the central
- mucocilliary escalator
cilia “beating”
does not regulate soluble phase
- cilia are too deep, below the surface, cannot beat effectively, bacteria can overgrow
cystic fibrosis
peripheral airways have laminar (straight) flow, allows _
for diffusion
alveoli have pores for _, collateral airflow
gas diffusion
volume moved during either an inspiratory or expiratory phase of each breath (L)
Tidal volume (Vt)
- reserve ability for inspiration (L)
- volume of extra air that can be inhaled after a normal inhalation (L)
inspiratory reserve volume (IRV)
volume of extra air that can be exhaled after a normal exhalation (L)
expiratory reserve volume (ERV)
- volume of air remaining in lungs following a maximal exhalation (L)
- usually increases with age
- allows for uninterrupted exchange of gases
Residual volume (RV)
- volume of air in the lungs at the end of a normal tidal exhalation (end tidal) (L)
functional residual capacity (FRC)
functional residual capacity is important for _
maintaining gas pressures in the alveoli
_ determined by:
- height, weight, age, gender
- compliance
- surfactant
- inspiration/expiration muscle strength
- maximal amount of air in the lungs
total lung capacity (TLC)
RV + VC =
TLC
maximal amount of air that can be moved in one minute (L/min)
maximal ventilatory volume (MMV or MBC)
2 types of ventilation
- pulmonary
- alveolar
_ type of ventilation:
- air is brought into lungs and exchanged with air in lungs (Ve)
pulmonary
_ type of ventilation:
- exchange of gases between alveoli and capillaries
alveolar
- at rest, usually ~ 6 L/min
- increase due to increase in rate and depth
- Rate: increased 35-45 breaths/min, elite athletes: 60-70 breaths/min, max
pulmonary ventilation
_ of _ tidal volume will enter into and mix with existing alveolar air
350 ml of 500 ml
_ will enter alveoli, but only _ is fresh air
- _ is about 1/7 of air in alveoli
- allows for maintenance of composition of alveolar air (concentration of gases)
- 500ml, 350 ml
- 350 ml
anatomic dead space _ with increase in _
- increases
- tidal volume
increase in dead space is still less than increase in _
- therefore, deeper breathing allows for more effective _, rather than an increase breathing rate
- tidal volume
- alveolar ventilation
gas exchange between the alveoli and blood requires ventilation and perfusion matching: V/Q
- at rest, 4.2 L of air for 5 L of blood each minute in alveoli, ratio ~.8
physiologic dead space
with light exercise,
V/Q is maintained
Disproportionate increase in alveolar ventilation
with heavy exercise
when alveoli do not work adequately during gas exchange, it is due to:
- under perfusion to blood
- inadequate ventilation relative to the size of the alveoli
Portion of alveolar volume with poor V/Q ratio is _
- small in healthy lung
physiologic dead space
if physiologic dead space is >60% of lung volume, adequate gas exchange is _
impossible
- spirometry (cannot determine RV and FRC)
- helium diffusion
- oxygen washout
- plethysmograph (in lab)
techniques of assessing lung volumes
plethysmograph based on
Boyle’s Law : P1V1 = P2V2
Rate of gas diffusion depends on two factors:
- pressure differential between gas above the fluid and gas dissolved in the fluid
- Solubility of the gas in the fluid
in humans: pressure difference between alveolar and pulmonary blood creates the driving force for _ across the _
- gas diffusion
- pulmonary membrane
if pressure of dissolved oxygen molecules exceeds the pressure of the _ in air, oxygen leaves the fluid until it attains a new _
- free gas
- pressure equilibrium
_ or dissolving power of gas determines the number of molecules that move into or out of a fluid
- expressed in millimeters of a gas per 100 ml (dl) of a particular fluid
solubulity
exchange of gases between the lungs and blood, and gas movement at the _ progress _ by diffusion, depending on their pressure gradients
- tissue level
- passively
- > 300 million alveoli
- elastic, thin-walled membranous sacs
- surface for gas exchange
- blood supply to alveolar tissue is greatest to any organ in the body
- capillaries and alveoli are side by side
alveolar ventilation
during alveolar ventilation: at rest, _ O2 leave alveoli in blood, and _ CO2 diffuse into alveoli
- 250 ml
- 200 ml
during heavy exercise, (TR athletes) _ in quality of O2 transfer
25x increase
molecules of gas exert their own partial pressure
- _: mixture of the sum of the partial pressures
- _: % concentration x total pressure of the gas mixture
- total pressure
- partial pressure
- Oxygen: 20.93% x 760 mm Hg = 159 mm Hg
- Carbon dioxide: 0.03% x 760 mm Hg = 0.2 mm Hg
- Nitrogen: 79.04% x 760 mm Hg = 600 mm Hg
ambient air at sea level
partial pressure is noted by _
Ex: PO2 = 159
P in front
- as air enters respiratory tract, it is completely saturated with water vapor
- water vapor will dilute the inspired air mixture
- at 37 degrees Celsius, water exerts 47 mm Hg
- 760-47=713
- recalculate pressures, PO2 = 149
tracheal air
- different composition than tracheal air because of CO2 entering alveoli from blood and O2 leaving alveoli
- average PO2 in alveoli ~ 103 mm Hg
- PCO2 = 39
alveolar air
-FRC is present so that incoming breath has minimal influence on composition of _
- therefore, partial pressures in alveoli _
- equal to alveolar volume (Va): 60-70% TLC
- normal 1.8-3.4 L
- alveolar air
- remains stable
PO2 is about 60 mm Hg higher in alveoli than in capillaries during _
- because of diffusion gradient, oxygen will dissolve and diffuse through alveolar membrane into capillary
gas transfer in lungs
- CO2 pressure gradient is smaller, ~ 6 mm Hg
- adequate gas exchange still occurs because of _ of CO2
high solubility
Nitrogen is _ or _ in gas transfer in the lungs
- _ is relatively unchanged
- not used or produced
- Partial pressure Nitrogen (PN)
_ is rapid during gas transfer in lungs, ~ 1 sec, midpoint of blood’s transit through the lungs
equilibrium
Gas transfer in lungs:
- during exercise, blood transit time _ ~ 1/2 of that seen at rest
- during exercise, pulmonary capillaries can _ in blood volume 3x resting
- this maintains the pressures of O2 and CO2
- decreases
- increase
Gas transfer in lungs:
- at rest, the pressure of oxygen molecules in blood exceeds oxygen pressure in the _ (60 mm Hg)
alveoli
Gas transfer in lungs:
- oxygen diffuses through the _ into the blood
alveolar membrane
Gas transfer in lungs:
- carbon dioxide transfer occurs _ because of _ in plasma
- rapidly
- high solubility
Gas transfer in lungs:
- _ in healthy lungs, alveolar gas-blood gas equilibrium takes place in 0.25 secs
- Equal to 1/3 bloods transit time through lungs
fast
at high intense exercise, _ of RBC does not exceed by more than 50% of _
- velocity
- resting velocity
with increasing intensity, pulmonary capillaries increase blood volume _
3x rest
- O2 leaves the blood and diffuses toward the cell
- CO2 flows from the cell into the blood
- Blood then passes the venous circuit back to the heart and lungs
- does not dump out all CO2
- provides the chemical basis for ventilatory control through a stimulating effect it has on the pons and medulla centers of the brainstem
Gas transfer in tissues
Gas transfer in tissues:
- at rest, PCO2 in fluid outside a muscle cell are rarely _ 40 mm Hg
- PCO2 is ~ 46 mm Hg
- less than
Gas transfer in tissues:
- During exercise, _ may drop to 3 mm Hg, and _ rise to 90 mm Hg
- O2 and CO2 diffuse into capillaries, carried to heart and lungs, where exchange occurs
- PO2
- PCO2
Gas transfer in tissues:
- Body does not try to completely eliminate CO2
- Blood leaves lungs with _ of 40 mm Hg, this is about 50 ml of carbon dioxide / 100 ml of blood
PCO2
Gas transfer in tissues:
- _ is critical for chemical input for control of breathing (respiratory center in brain)
PCO2
By adjusting alveolar ventilation to metabolic demands, the composition of _ will stay constant, even during _ (which can increase VO2 and CO2 production by 25x)
- alveolar gas
- strenuous exercise
_ meets metabolic demands constantly
alveolar ventilation
stability of the _ concentrations are maintained (FRC) even during strenuous exercise where oxygen consumption and carbon dioxide output can be _ than rest
- alveolar gas
- 25x
Gas transfer in tissues:
- blood carries oxygen in two ways
- in physical solution dissolved in the fluid portion of blood
- loose combination with hemoglobin
- at alveolar PO2 of 100 mm Hg - only about 0.3 ml of oxygen dissolves in a dl of blood
- ~ 3 ml of oxygen per liter of blood
O2 in physical solution
Gas transfer in tissues:
- sole source of oxygen in blood would need to circulate _ of blood a minute to meet oxygen requirements
- at rest
80 L
Gas transfer in tissues:
- iron-protein pigment in RBC
- increases carrying capacity to _ that carried in solution plasma
- ~ 280 million molecules in each of the 250 trillion RBC
hemoglobin
Gas transfer in tissues:
- with _, small amount of _ dissolved in plasma exerts molecular movement and establishes the partial pressure of _ in the blood
- hemoglobin
- oxygen
- oxygen (PO2)
Gas transfer in tissues:
- plasma PO2 determines _ at the lungs (oxygenation) and its _ at the tissues (deoxygenation)
- the loading of hemoglobin
- unloading
- decrease in iron content of RBC will reduce blood’s oxygen-carrying capacity
- lower hemoglobin concentration impairs aerobic exercise performacne
iron deficiency anemia
- oxyhemoglobin dissociation curve shows that hemoglobin saturation changes very little until pressure is below 60 mm Hg
- quantity of oxygen bound hemoglobin falls sharply as oxygen moves from capillary blood to tissues when metabolism demand does up
oxygen transport cascade
- atmospheric (dry) 159 mm Hg - humidify
- lower respiratory tract 159 mm Hg - O2 + CO2 + alveoli
- alveoli PaO2 104 mm Hg - _
- arterial PaO2 100 mm Hg - _
- venous blood PvO2 40 mm Hg
- mitochondria PO2 7-37 mm Hg
- oxygen cascade
- venous mixture
- tissue extraction
oxygen cascade:
- _ releases only about 25% of its total oxygen content to tissue at rest
- remaining 75% returns _ to the heart in venous blood
- arterial blood
- unused
oxygen cascade:
- major difference in oxygen content of arterial and venous blood under resting conditions indicates that there is a _ for rapid use in case of immediate metabolism increase (fight or flight response)
reserve of oxygen
- provides an “extra” oxygen store to release oxygen at low PO2
- during intense exercise, facilitates oxygen transfer to mitochondria with intercellular PO2 in active skeletal muscle decreases dramatically
myoglobin
gas transfer in tissues:
- blood carries CO2 in 3 ways:
- physical solution in plasma
- combined with hemoglobin with RBC
- as plasma bicarbonate
CO2 gas transfer in tissues:
- ~5% of CO2 formed during energy metabolism moves into _ in the plasma
- dissolved CO2 establishes the PCO2 of the blood (important for physiologic functions)
- CO2 in physical solution
- physical solution
CO2 gas transfer in tissues:
- majority of CO2 transported during chemical reaction with water to form _
- 60-80%
- plasma bicarbonate
- bicarbonate
CO2 gas transfer in tissues:
- about 20% of the body’s CO2 combines with blood proteins including hemoglobin to form _
carbamino compounds
O2 transport in the blood:
- at _, 15 ml of O2 carried through body/minute
- would sustain life for about 4 seconds
- random movement of dissolved O2 establishes PO2 of the blood and tissue fluids
Q of 5 mL/min
O2 transport in the blood:
- pressure of dissolved oxygen establishes the _ of the blood
- pressure of dissolved oxygen is important in the _
- also determines the loading and subsequent release of O2 from hemoglobin in the lungs and tissues (respectively)
- PO2
- regulation of breathing
Oxygen combined with _
- increases oxygen carrying capacity 65-70x
- for each liter of blood, 19.7 ml of oxygen are captured (temporarily) by _
- hemoglobin
- hemoglobin
oxygen combined with hemoglobin:
- each of the 4 iron atoms in the hemoglobin molecule can loosely bind to _ of oxygen
- requires no enzyme
- occurs without a change in valence of Fe+
- the oxygenation of hemoglobin to oxyhemoglobin depends entirely on _ in the solution
- one molecule
- PO2
Oxygen _ of hemoglobin
- males have 15-16g of Hb/100 ml of blood
- females have 5-10% less, about 14g/100 ml
- gender difference may account for some lower values in maximal aerobic capacity even after differences in body fat and size are accounted for
carrying capacity
each gram of blood is known, the oxygen carrying capacity can be calculated : _
- 20 mol/O2/100 ml = 15x 1.34 O2/g
- usually ~ 20ml of O2 is carried with Hb in each 100 ml of blood when Hb is fully saturated
bloods capacity = Hb x o2 capacity of Hb
Oxygen carrying capacity of hemoglobin:
- if there is significant decrease in fe in the RBC, _ in the oxygen carrying capacity of the blood, decreases the _ mild aerobic capacity (anemia)
- decreases
- ability to sustain
_ in the lungs:
- hemoglobin is about 98% saturated with O2 at alveolar PO2 of 100 mm Hg
- therefore, each 100 ml of blood leaving the alveoli has about 19.7 ml of O2 carried by hemoglobin
- remember, 0.3 ml of O2 is dissolved in the plasma component of the blood
- This plasma PO2 regulates the _
- PO2
- loading and unloading of Hb
PO2 in the lungs:
- saturation of Hb changes little until the pressure of O2 falls to about 60 mm Hg
- This flat, upper portion of the _ provides a margin of safety
- at ~ 75 mm Hg (altitude or lung disease) saturation is lowered by ~ 6%
- If PO2 is lowered to 60 mm Hg, hemoglobin is still _
- O2 dissociation curve
- 90% saturated
_ in the tissues:
- differences in O2 content in arterial and mixed venous blood is the _ or the (a-v)O2 difference
- PO2
- arteriovenous difference
PO2 in the tissues:
- large amounts of O2 remains bound to hemoglobin, providing a _
- this can provide immediate oxygen, if the demand suddenly increases
- when the cells need O2 (exercise), the tissue _, leading to a rapid release of a large quantity of O2
- reserve
- PO2 lowers
PO2 in the tissues:
- during vigorous exercise, extracellular _ about 15 mm Hg, only 5 ml of O2 remain bound to Hb
- (a-v)O2 difference _ to about 15 ml of O2/100 ml blood
- PO2 decreases
- increases
If tissue PO2 falls to 3 mm Hg during exhaustive exercise, almost all the _ from the blood that perfuses the active tissue
- without any increase in _, amount of O2 released to muscles can increase almost 3x above resting, due to more complete _ of Hb
- a working muscle can extract _ of O2
- oxygen is released
- local blood flow
- unloading
- 100%
_ effect is the presence of H+ ions in contracting muscle unloads O2 from Hb
- the reduced effectiveness of hemoglobin to hold O2, especially in PO2 ranges of 20-50 mm Hg
Bohr
at _, bohr effect in pulmonary capillary blood is negligible
- allows Hb to _ with O2 as the blood passes through the lungs, even during maximal exercise
- PO2 in alveoli
- load completely
- produced within the RBC during glycolysis (anaerobic)
- binds loosely with subunits of Hb molecule
- reduces the affinity for O2, shifting the curve
- enhances the _ of O2 in the tissue
- Red blood cell 2,3-DPG (diphosphoglycerate)
- unloading
unlike the response of H+ ions to unload quickly, 2,3-DPG operates at a _, allowing adaptions to _ in O2 availability
- if PO2 decreases, _ O2 is released to the tissues
- slow rate
- gradual changes
- more
high levels of _ in RBCs for those who live at high altitudes and those with cardiopulmonary disorders
- half life is small, ~ 6 hours if return to low altitudes
2,3-DPG
Endurance training may increase _ after maximal exercise for short duration, while training has no benefit during prolonged, _
- females appear to have higher levels, may compensate for lower Hb levels
- 2,3-DPG
- steady-state exercise
Regulation of _
- buffer system – seconds
- phosphate buffer system
- carbonic/carbonate system
- blood proteins, especially Hb
- respiratory system – minutes
- ventilation rate is controlled to keep sufficient CO2 in blood to maintain pH
- Kidneys – days
- excrete bicarbonate (HCO3-) at the rate that optimizes pH
blood pH
Functions of the _
- delivery of O2 to tissues
- disposal of CO2 produced by the tissues
- maintenance of a stable blood pH at 7.4
respiratory system
Control of _ during exercise:
- humoral stimuli
- neural stimuli
ventilation
control of ventilation during exercise:
- changes in physical and chemical properties in blood from normal values at rest
humoral stimuli
control of ventilation during exercise:
- originates in the brain center
- respiratory center
- medical conditions, Ex: emotions
- inflation and deflation (stretch) of the lungs
- muscle contraction and limb movement or tension development
neural stimuli
- called “singultus”
- sudden, involuntary contractions of the diaphragm muscle
- as muscle contracts repeatedly, the opening between the vocal cords snaps shut to check the inflow of air and makes the sound
- irritation of the nerves that extend from the neck to the chest
hiccups
causes of hiccups:
- none showed to be cause but can be associated to _
- eating too fast: swallowing air along with food
- irritating diaphragm with excessive drinking or too much fatty foods
- hiccups can last a few seconds to a few hours
- seek medical attention after 3 hours
- can effect sleeping patterns
hiccup timeline
- diaphragm spasm that occurs when a sudden force is applied to the abdomen or back
- applies pressure to solar plexus
- results in temporary paralysis of diaphragm making it difficult to breath
- its a few seconds for diaphragm to relax again before normal breathing can resume
wind knocked out of you
- increased pulmonary ventilation that exceeds gas exchange needs for metabolism
- also termed “over breathing”
- causes lower concentration of CO2
hyperventilation
- forced exhale against a closed glottis
- action will create increase in pressure within chest and abdominal cavities, which compresses veins- reducing venous return to heart
- overall reduces arterial blood pressure
valsalva maneuver
- cold air does not damage respiratory passages
- in cold weather, the respiratory tract loses considerable water and heart (heavy ventilation)
- post _ is directly related to overall respiratory water loss, not heart loss
post exercise cough
- consists of continuous linkage of a pump, high-pressure circuit, exchange vessels, and a low-pressure collection and return circuit
- if stretched out there would be 100,000 miles of blood vessels of an adult would encircle the earth 4x
- small arteries, veins and capillaries contain nearly 75% of total blood volume
- heart ~7%
- Lungs ~8-9%
components of cardiovascular system
- transport of O2 to tissues and remove waste (delivery and garbage)
- transport nutrients to tissues
- regulate body temperature
- right and left sides have different functions
overall function of cardiovascular system
- arteries: elastic and muscle fibers in wall
- veins: allow flow in one direction
- aorta
- carotid
- femoral brachial
- superior/inferior vena cava
- venules
- capillaries
important structures of the cardiovascular system
Heart is a _ muscular organ
- 2 pumps, pulmonary and systemic circulation
- heart muscle is called _
- striated, with actin and myosin filaments, similar to skeletal muscle
- Weight: 11oz male, 9 oz female
- ~ 2/4 oz/beat
- at rest, _ gallons/day or 52 million gallons over a 75-year lifespan
- 4 chambered
- myocardium
- 1,900
average fitness level hearts at _ exceeds in one minute the fluid output of a household faucet turned wide open
max output
Heart connected by _ that allows chemical and electrical coupling between cells
intercalated disks
Heart pump:
_ side:
- receive blood returning from throughout the body
- pump blood to the lungs for aeration through the pulmonary circulation
right
Heart pump:
_ side:
- receive oxygenated blood from the lungs
- pump blood into thick-walled, muscular aorta for distribution throughout body in systemic circulation
left
cardiac chambers: _
- thin walled, sac-like chambers, low pressure
- function is to receive and store blood while ventricles are contracting, act as primer pumps
- _ is more important than pump for blood propulsion
- atria
- reservoir
cardiac chambers: _
- are a continuum of muscle fibers
- contract from apex to base
- R ventricle is thicker than R atria
- L ventricle is _ than R ventricle walls
- L ventricle can develop 4-5x more pressure than the R ventricle
- ventricles
- 3x thicker
there are a number of _ in the heart
- thin flaps of endothelium covered fibrous tissue
- movement of the valve leaflets are essentially passive
- orientation of valves are responsible for the _ through the heart
- valves
- unidirectional flow of blood
Valves in the heart:
- _ prevents backflow of blood from the ventricles into the aorta
- also called tricuspid valve (three flaps or cusps) and mitral valve (bicuspid, two flaps or cusps)
atrioventricular valves
Valves in the heart:
- between right ventricle and pulmonary artery is a semilunar valve (three cusps) also called _
pulmonic valve
Valves in the heart:
- between left ventricle and aorta are _ (prevents backflow of blood from aorta into the heart)
semilunar valve
Blood flow through the heart:
- step one: blood flows into _
right atrium from superior and inferior vena cava
Blood flow through the heart:
- step two: blood travels from _
R atrium into R ventricle
Blood flow through the heart:
- step three: blood flows through _
pulmonary artery into the lungs (for oxygenation)
Blood flow through the heart:
- step four: blood returns from the _
lungs through the pulmonary veins, and is deposited into L atrium
Blood flow through the heart:
- step five: from L atrium, blood flows into _
L ventricle
Blood flow through the heart:
- step six: blood leaves _
L ventricle via aorta, enters general systemic circulation
Heart has _ rhythmicity
intrinsic
Flow of electricity through the heart:
- step one: originates in _
Sinoatrial node (SA node), superior, lateral aspect of R atrium
Flow of electricity through the heart:
- step two: travels through _
both atria to atrioventricular node (AV node), this causes depolarization of atria
Flow of electricity through the heart:
- step three: from AV node, pause for 0.01 sec, flows through _
AV bundle (Bundle of HIS) through R and L bundle branches (RBB, LBB)
Flow of electricity through the heart:
- step four: from RBB and LBB, signal travels to the _
perkinje fibers in ventricles, which passes the current of depolarization to the ventricle muscle
ventricles have a powerful contraction, and provide the major impetus to _ throughout the CV system
more blood
_ in cardiac muscle
- resting membrane potential of normal cardiac muscle is -85 to -95 millivolts
- specialized conductive fibers, _, have a resting membrane potential of -90 to - 100 millivolts
- _ has a magnitude of ~105 mv
- this ride is ~ +20 mv greater than needed, called the _
- action potentials
- perkinje
- overshoot potential
action potentials in cardiac muscle:
- after depolarization, remains depolarized for 0.2 seconds in atrial muscle and 0.3 seconds in ventricular muscle, which gives it the _
- plateau is followed by abrupt _
- this plateau causes a _ to last 3-15x longer than a skeletal muscle twitch
- plateau
- repolarization
- contraction
action potential is caused by the opening of two types of channels:
- fast sodium channels allow the sodium ions to enter the cell
- slow calcium channels are slower to open and remain open longer (can be several tenths of a second; sodium can also pass through these channels)
The _ of cardiac muscle membranes to potassium decreases about 5x
- this decreases the _ during plateau, preventing early recovery
- when Na and Ca channels close, influx _, permeability for K _
- rapid influx of K, membrane potential returns to _
- permeability
- outflux of K
- stops
- increases
- resting
cardiac muscle has a _, preventing restimulation
- during this interval, a normal cardiac impulse cannot re-excite an already excited area of the heart
refractory period
Refractory period of cardiac muscle:
- ventricles: 0.25-0.30 seconds
- another, relative refractory period of 0.05 seconds, muscle is more _ to excite, but can be stimulated
- atria: ~ 0.15 seconds
- Relative refractory: 0.03 seconds
- _ of atria can be faster than that of ventricles
- difficult
- rhythmical rate
- beginning of heart beat to beginning of the next
- R to R or P to P wave is often how one is measured
cardiac cycle
Relaxation phase: heart fills with blood, _
- first third: rapid filling
- middle third: small amount of filling
- last third: atria contract, ~25% of blood flows into ventricles
diastole
working phase: heart pumps blood, _
- isovolumic contraction occurs at onset of ventricular contraction
- ventricles need to develop sufficient pressure to open semilunar valves against the aorta and pulmonary artery
- ventricles contract isometrically, volume _
- systole
- does not change
process of _
- pressure in L ventricle > 80 mm Hg and R ventricle > 80 mm Hg, valves _
- first third: rapid, 70% of blood
- next two thirds: final 30% is ejected, _
- isovolumic relaxation
- sudden _, rapid _, no change in volume
- interventricular pressure drops to _ level
- ejection
- open
- slow ejection
- onset
- drop
- diastolic
- volume in ventricles after the period of filling
- usually ~ 110-120 ml of blood/ventricle
end diastolic volume (EDV)
- volume ejected during systole
- ~70 ml
stroke volume (SV)
- volume in ventricles after systole
- ~40-50 ml
end systolic volume (ESV)
- fraction of EDV that is ejected is called the _
- usually ~60%
- when contraction force is _, ESV can fall to 10-20 ml
- EDV can be as high as 150-180 ml of blood
- _ in EDV and _ ESV, SV and double resting SV
- ejection fraction (Ef)
- strong
- increase
- decrease
Volume pressure curves for systole and diastole:
- phase _: filling phase ESV to EDV increase volume ~70% ml, pressure rises ~5 mm Hg (diastolic)
1
Volume pressure curves for systole and diastole:
- phase _: isovolumic contraction, increase pressure (~80 mm Hg), not volume
2
Volume pressure curves for systole and diastole:
- phase _: ejection period
3
Volume pressure curves for systole and diastole:
- phase _: isovolumic relaxation ventricle pressure decreases to diastolic levels
4
_ in the cardiovascular system
- degree of tension on the heart muscle when it begin to contract
preload
_ in the cardiovascular system
- load against which the muscle exerts its contractile force
- pressure in artery leading away from the ventricles
afterload
- as arterial pressure increases, work output of stroke volume increases until it reaches the limit of the heart
- as arterial pressure increases (EDV), ejection fraction also increases
ventricular function curves
neural input coordinates the rapid adjustment of the heart and blood vessels to optimize tissue perfusion and maintain blood pressure in relation to muscle usage
- operates during pre-exercise anticipatory period and during early stage of exercise
command center
central control center provides the greatest control over _ during exercise
heart rate
Command center:
- high neural outflow from the central command in _ of exercise and immediately at the start seems desirable for intense _ to mobilize physiologic reserves rapidly
- on the flip side, this before a long distance race would seem wasteful
- _ also increases in anticipation of exercise
- anticipation
- sprint activity
- blood flow
_ regulation of the heart rate
- neural influences can be superimposed on inherent rhythmicity of heart
- originate in CVC in medulla
- transmitted via autonomic NS via sympathetic and parasympathetic
- ventricles: _
- atria : _
- extrinsic
- sympathetic
- both
_ innervation
- can increase Q by 100%
- causes release of epi and norepi, speeding rate of SA depolarization
- Result: tachycardia
- also increases the force of contraction
sympathetic
Inhibition of sympathetic nervous system can _
decrease heart rate and pumping
sympathetic innervation:
- mechanism that continuously discharges, maintains HR ~30% higher than if there were no stimulation
- if depress _, HR and force of contraction decreasing Q ~30%
- _ are also active and can release epi with general sympathetic activation
- sympathetic stimulation
- adrenal glands
_ innervation:
- can slow heart rate to almost zero
- Ach released, decreasing the rate of sinus discharge: brachycardia
- cell bodies are in cardioinhibitory center of medulla
- with wrong stimulus, heart can stop beating for a few seconds, start again, at a rate of 20-30 bpm
parasympathetic
parasympathetic innervation:
- strong _ will decrease the force of contraction by 20-30%
- decrease is not great in its extent, most fibers are in atria, few in ventricles
- large _ combined with small _ : decrease ventricular pumping 50%
- parasympathetic stimulation
- decrease in HR
- decrease in contractility
Training effect:
- exercise favors vagal dominance
- increase in _ activity, may also have a decrease in _ activity
- training may also reduce intrinsic firing rate of SA node
- training specificity
- heart rapidly “turns on” in exercising by decreasing _ input and increases _ input from the brain’s central command
- parasympathetic
- sympathetic
- parasympathetic inhibitory
- stimulating
_ input:
- receptors in blood vessels, joints, muscles
- input to ventrolateral medulla
- modify vagal or sympathetic outflow
- _ in aortic arch and carotid sinus (alterations in BP)
- peripheral
- baroreceptors
peripheral input:
- increase _: reflex slowing of HR and dilation of peripheral vasculature
- decrease _
- this feedback is overriden during _
- but, still may act to prevent abnormally _ during exercise
- blood pressure
- BP to normal levels
- high BP
carotid artery palpation:
- external pressure on carotid artery may _
- due to direct stimulation of baroreceptor in carotid artery
- still appropriate to _
- slow HR
- measure HR during exercise
_ input:
- impulses from cerebral cortex pass via afferent nerves through CVC in medulla
- allows emotional state to influence _
- cortical
- CV response
cortical input:
- impulses cause HR to rise rapidly _ (anticipatory HR)
- probably due to increase in sympathetic discharge and decrease in vagal tone
- _ of increase is greatest in short sprint events and lower in longer events
- represents a 74% increase in HR during a 60yd sprint
- prior to exercise
- magnitude
large portion of HR adjustment to exercise reflects the cortical input that occurs during _
- receptors in joints and muscles (muscle afferents) probably provide a large amount of input to increase HR during _ as well
- initial stages of activity
- initial stage
Heart as pump:
- increase _ – increase in _ ; limitations
- once HR reaches a certain level, strength of contraction decreases, may be due to _ of substrates in cardiac muscle
- period of _ is short, cannot fill adequately
- HR
- SV
- overuse
- diastole
Heart as pump:
- with _: peak ability to pump blood is 100-150 bpm
- with _: increase HR and strength of contraction peak ability - 170-220 bpm
- cardiac contractility
- artificial stimulation
- sympathetic stimulation
Heart as pump:
- _: rate of change of ventricular pressure with respect to time
- way to assess the strength of the contraction of the heart
- as ventricular pressure increases at its most rapid rate, the _ also peaks
- usually, rate of ventricular pressure correlates well with strength of ventricular contraction
- delta P / delta t
- delta P / delta t
Heart as pump:
- Two factors that influence delta P / delta t which are NOT related to cardiac contractility are:
- increased input pressure to the L ventricle (EDV, Preload)
- pressure in the aorta, afterload
Influence of potassium (K) and calcium (Ca) ions:
- excess potassium in extracellular fluids causes heart to become _, _ and _
- large quantities can block the cardiac impulse from the atria to the ventricles via AV bundle
- elevations of 2-3x normal can weaken heart enough to lead to _
- dilated
- flaccid
- slows HR
- death
Influence of potassium (K) and calcium (Ca) ions:
- high extracellular potassium concentrations can cause a decrease in the _ in cardiac muscle fibers
- lower _ – decrease in action potential – weaker contraction
- resting membrane potential
- resting membrane potential
Influence of potassium (K) and calcium (Ca) ions:
- excess calcium causes opposite effect of excess potassium
- heart goes into _
- due to direct influence of Ca ions in exciting the _
- deficiency in ca will cause flaccidity, similar to excess K
- changes due to Ca are rare, blood levels are tightly _
- spastic contraction
- cardiac contractile process
- controlled
- increased temperature (T) will increase _, sometimes as much as 2x
- decreased T will cause body temperature to drop 60-70 degrees f, near _
- moderate T increase can enhance the _ of the heart
- prolonged elevation in T can cause exhaustion of the metabolic systems of the heart, causing _
- HR
- death
- contractile strength
- weakness
Blood transport:
- arteries carry _ (except pulmonary artery)
- composed of connective tissue and smooth muscle
- from aorta (elastic as well as muscular), through arteries, arterioles, metarteries, and finally capillaries
oxygenated blood
Blood transport:
- _: smooth muscle; can constrict and dilate dependent on peripheral blood needs
- metarteries are less muscular
arterioles
Blood transport:
- _: microscopic blood vessels which contain ~5% of the total blood volume
- single layer of endothelial cells, may abut the membranes of surrounding cells
- density may be 2-3,000/mm^2
- _ is higher in cardiac muscle
- capillaries
- capillary density
Blood transport: capillaries
- precapillary sphincter controls _ in the capillaries of specific tissues
- ~ _ seconds to pass a blood cell through an average capillary (effective way to exchange)
- blood flow
- 1.5
Blood pressure (BP):
- surge of blood enters the _ every time the L ventricle contracts
- portion is stored in aorta, arteries, and arterioles - cannot handle the rapid run off of blood _
- causes a pressure wave through the _ system (pulse)
- aorta
- equal to ejection
- arterial
Blood pressure (BP):
- _: average pressure in the arterial system during the cardiac cycle
- spend more time in diastole, it is a little less than average of _ and _
- mean arterial pressure (MAP)
- diastole
-systole
Blood flows from capillaries into venules to _
- blood from lower body enters the heart via _
- blood from the head and shoulders empties into _
- when blood enters veules, the impetus for flow is minimal (low pressure)
- veins
- inferior vena cava
- superior vena cava
Veins:
- Bloods returns via:
1. _
2. _
- couple the one-way valves with the compression, milking action returns blood
- 65% of blood volume is in veins at rest
- veins are considered capacitance vessels and reservoirs for blood
- flap-like valves (one-way) at short intervals in veins
- valves are easily compressed by neighboring muscles
_: due to hardening of arteries, excessive peripheral resistance
- enhanced nervous tone or kidney malfunction
hypertension
Hypertension and exercise:
- pressures of 200-300 for _ and > 90 mm Hg for _
- aerobic exercise can modestly lower BP
- extent is unclear, but beneficial for normotensive and hypertensive individuals
- systole
- diastole
Hypertension and exercise:
- resting BP _ significantly, possible due to higher circulating _ after training – decreased _ to blood flow, decreasing BP
- exercise may enhance sodium elimination by kidneys
- lowers
- catecholamines
- peripheral resistance
BP and resistance training:
- static and dynamic resistance exercise will _ to blood flow
- even at light loads
- potential for harm for those with heart and vascular disease
- chronic resistance training does not appear to _ , and can blunt the response to a single bout
- increase peripheral resistance
- increase BP
BP and resistance training:
- _: pinch your nose, close mouth, try to exhale, or bear down, 10-15 seconds – pop your ears
valsalva
BP and resistance training:
- 4 phases to relax heart’s electrical system:
- pressure rises in chest and belly
- heart pumps less blood
- relax- HR increases
- recovery
BP and resistance training:
- dilation of blood vessels in working muscles will decrease TPR, increase BF to working muscles
- may see a small rise in systole, 140-160 mm Hg, then levels off
- diastole may increase or decrease 10 mm Hg, or remain unchanged
steady-state exercise
BP and resistance training:
- increase in systole, mean, and diastole with increase Q
- greatest changes are in systole, diastole may change only ~12%
graded exercise
BP and resistance training:
- systole and diastole significantly higher than with leg exercise, even at same intensity
- may be due to smaller vasculature
arm exercise
BP and resistance training:
- after submax exercise, systolic pressure can be temporarily (2-3 hours) depressed below pre-exercise levels
- because TPR remains low after exercise
recovery
Heart blood supply:
- has its own supply
- has _
- at rest, normal _ is ~ 200-250 ml, 5% of Q
- dense capillary network
- blood flow to myocardium
myocardial oxygen utilization:
- at rest, 70-80% of oxygen _ from the blood in _
- in other tissues, at rest, ~25% of the oxygen is extracted
- coronary blood flow will _ during exercise to meet _, can increase 4-6x above resting levels
- extracted
- coronary vessels
- increase
- myocardial oxygen requirements
Two ways to increase myocardial blood flow:
- coronary BF is 2.5x greater during diastole than during systole
- heart has limited ability to generate energy anaerobically
- increased myocardial metabolism causes dilation of coronary vessels
- increased aortic pressure forces a larger amount of blood into coronary circulation
myocardial metabolism:
- has a 3x higher oxidative capacity than _
- have the greatest mitochondrial density, well adapted for fat catabolism as primary source of ATP synthesis
- _, _ and, _ provide energy for the heart
- skeletal muscle
- glucose
- fatty acids
- lactate
myocardial metabolism:
- during heavy exercise, with a large concentration of _ in the blood, the heart can use lactate for 50% of its total energy
- during prolonged submax activity, 70% of energy comes from _
- metabolic patterns are similar for TR and UNTR but, Tr have a greater contribution of fats to the total energy requirement
- lactic acid
- fatty acids
_: estimate of myocardial work
- increase in myocardial contractility and heart rate will increase the demand for oxygen
- estimate myocardial workload and oxygen consumption, use product of peak systole and heart rate
- index of relative cardiac work
rate-pressure product
- also called the double product: _
- highly related to _ oxygen consumption and _
- RPP = _
- rate-pressure product
- myocardial
- coronary blood flow
- SBP x HR
Rate-pressure product:
with training in cardiac patients, a higher RPP can be achieved before _ symptoms appear
- this measure is used in coronary heart disease patients
- ischemic (heart attack)
Blood distribution:
- rapid adjustments are necessary during exercise, possible by _ and _ of smooth muscular bands of arterioles
- additionally, venous capacitance vessels _
- can rapidly redistribute blood to meet _ of exercise, while preserving _ and _ throughout the system
- constriction
- dilation
- stiffen
- metabolic demands
- adequate flow
- pressure
Regulation of blood flow:
- _ is most important factor regulating regional flow
- resistance to flow changes with vessel diameter (to the 4th power)
- reducing diameter by 1/2, causes flow to decrease _
- changing diameter of blood vessels
- 16x
- 1 in 30-40 capillaries are open at rest, opening capillaries during exercise will:
- increase muscle blood flow
- due to the increase in channels, increased blood volume can be delivered with only small increases in velocity flow
local factors
Local factors:
- enhanced vascularization will increase the effective surface for _ between _ and _
- local factors can increase _ of arterioles and precapillary sphincters
- exchange
- blood
- muscle cells
- dilation
Local factors: _
1. decrease in O2 supply
2. increase in temperature
3. increase in CO2
4. increase in acidity
5. increase in adenosine
6. increase in ions of magnesium and potassium
autoregulatory mechanisms
Neural factors:
- sympathetic and to a small extent parasympathetic portions of autonomic ns provide a central _
- muscles contain _ fibers which are sensitive to substances released in local tissue during exercise: _
- vascular control
- sensory nerve
- causes vascular responses
Neural factors:
- central regulation ensures that the area with the most need for _ gets the most _
- oxygen
- blood flow
Neural factors:
- norepinephrine is the _, and is released at certain sympathetic nerve fibers (adrenergic fibers)
- other sympathetic fibers can released Ach, causing _ (cholinergic fibers)
- dilation of blood vessels is due more to reduction in _ than to an increase in action of either sympathetic or parasympathetic dilator fibers
- general vasoconstrictor
- vasodilation
- vasomotor tone
Hormonal factors:
- sympathetic nerves _ in the medullary portion of the adrenal gland
- with activation, epi released in large quantities, norepi cause a _ response, except in blood vessels of the heart and skeletal muscles
- terminate
- constrictor
Hormonal factors:
- during exercise, hormonal control is minor in the control of _
- Bf is decreased to the _, _, _, _, and _ as a general response
- regional blood flow
- skin
- gut
- spleen
- liver
- kidneys
Integrated response in exercise:
- Nerves centers above the medullary region are above both before and at the onset of exercise to cause increases in the _ and _ of the heart, as well as to change regional blood flow
- rate
- contractility
integrated response in exercise:
- symptomatic cholinergic outflow plus local metabolic factors acting on _ and on _ cause dilation in active muscles
- reduces _, allowing for greater blood flow
- constriction adjustments will then occur in less active tissues as exercise continues, so that _ can be eliminated
- chemosensitive nerves
- blood vessels
- peripheral resistance
- perfusion pressure
Integrated response in exercise:
- 3 factors influencing venous return:
- action of muscle and ventilatory pumps
- stiffening of veins
- increase in venous tone with an increase in Q
Cardiac output:
- Q = _
- primary indicator of the _ to meet the demands of Pa
- HR x SV
- functional capacity of the circulation
- indirect fick
- indirect dilution
- CO2 rebreathing, indirect fick
- impedence
four methods to determine Q
Method for determining Q:
- 1. _
- Q =Q2 consumed / (a-v)O2
direct fick
Method for determining Q:
- 2. _
- examin an indicator dilution curve (not as accurate)
indirect dilution
Method for determining Q:
- 3. _
- Q = CO2 production / (v-a)CO2 x 100
CO2 rebreathing, indirect fick
Method for determining Q:
- 4. _
- SV
- preload
- afterload
- contractility
- BP
- systemic vascular resistance (SVR)
- can index the values to body size
impedence
Cardiovascular responses to exercise:
- increased Q
- increased _ and _
- enhanced delivery of _ and fuels to active muscle and removal of _ and waste
- HR
- SV
- O2
- CO2
Cardiovascular responses to exercise:
- increased skin _
remove heat
blood flow
Cardiovascular responses to exercise:
- decreased blood flow to _
- decreased urinary output and maintenance of blood volume
- decreased _ flow
- reduced GI activity
- kidneys
- visceral
Cardiovascular responses to exercise:
- maintenance or slight increase in brain BF
- increased BF to coronary arteries
- Increased muscle BF
- maximal flow is limited by need to maintain BP
- active muscles will vasoconstrict if _
BP is not maintained
Cardiovascular regulation directed to _
- balance between maintaining BP and need for more blood to active tissue
maintain blood pressure
Limits of CV performance:
- VO2 max is best predictor of CV capacity
- biochemical factors are better predictor of _
- Q is the best predictor of _
- Q can increase by 20% from endurance training, accounts for most of improvement t of VO2 max
- endurance
- VO2 max
CV changes with training:
- improved ability to _, increase SV (increase EDV, small increase in L ventricular mass)
- no change in _ volume
- increase SV, decrease HR = more efficient _
- pump blood
- ventricular
- pressure-time relationships
CV changes in training:
- may increase VO2 max by 20% depending on initial fitness (endurance more)
- submax and resting HR are _
- SV increase no more than 20% (increased myocardial contractility)
- slight increase in (a-v)O2, right shift in _
- resting BP, submax BP and MAP are _
- lower
- dissociation curve
- lower
Cv changes in training:
- coronary BF _ at rest and submax flow
increased SV and decreased HR = reduced _
- no change in the vascularity of the heart
- skeletal muscle _ increases
- decreased blood flow during submax work
- decreases
- myocardial oxygen consumption
- vascularity
