EXAM 2 Flashcards
(354 cards)
1
Q
_ is exemplified by:
- segmental anatomy
- pores between alveoli
- lobes
A
redundancy
2
Q
- warm the air
- transport the air
- are dead space
- conduct gas conly
A
conducting zones
3
Q
gas pressures equilibrate due to solubility and pressure differentials
A
Henry’s Law essentially
4
Q
During exercise, _ due to:
- increase in breathing rate
- increase in breathing depth
A
Ve increases
5
Q
_ is:
- airlessness
- why we move at night
A
atelectasis
6
Q
_ is an example of restrictive pulmonary disease
A
asthma
7
Q
Primary reason CO2 equilibrates so quickly is _
A
sollubility
8
Q
Inspiration is always _
A
active
9
Q
Expiration can be _
A
active and passive
10
Q
an individual with cystic fibrosis is at greater risk for lung infection because _
A
the fluid layer is too high
11
Q
_ increases with age due to loss of elasticity
A
residual volume (RV)
12
Q
Functional Residual Capacity (FRC) is important because
A
maintains pressure for adequate gas exchange
13
Q
Two types of ventilation are _
A
pulmonary and alveolar
14
Q
_ increases with exercise due to:
- an increase in tidal volume
- an increase in depth
A
anatomic dead space
15
Q
_ is:
- too much ventilation for the blood flow
- too little ventilation for the blood flow
- mismatch between ventilation and blood flow
A
physiologic dead space
16
Q
partial pressures in the lung are
A
lower than the trachea
17
Q
Two ways oxygen is carried in the blood _
A
- bound to hemoglobin
- bound to RBC
18
Q
cardiac output at rest is typically _
A
4-6 L/min
19
Q
The (a-v)O2 difference describes
A
tissue uptake of oxygen
20
Q
A change in the shape of the hemoglobin molecule
A
Bohr effect essentially
21
Q
_ increases with altitude
A
2,3-DPG
22
Q
myoglobin does not have a Bohr effect because
A
myoglobin carries only one oxygen
23
Q
- is a forced exhale against a closed glottis
- increases thoracic (chest pressure)
- reduces venous return
A
valsalva maneuver
24
Q
Normal _ (healthy)
- is about 0.5 L
- is mostly fresh air
A
tidal volume
25
The physiologic dead space is problematic when it
is more than 60% of lung volume
26
The heart is a _
muscular organ
27
Functions of _ :
- transport O2 and CO2
- transport nutrients
- regulate temperature
cardiovascular (CV) system
28
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
29
stimulation of the heart is conducted
via intercalated disks
30
Contraction of the _ is 3-15X longer than the contraction of skeletal muscle
heart
31
The electrical stimulus for the heart originates in the _
right atrium
32
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
33
The absolute refractory period in the heart
prevents the heart from contracting
34
The atria have a shorter refractory period than the ventricles. This then allows _
the atria to have a faster rate than the ventricles
35
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
36
End systolic volume (ESV) is typically _ (at rest)
about 40-50 ml
37
When ejection fraction is 30% or less of total ejection the prognosis for life is _
not good
38
A normal cardiac cycle is best measured _
R to R
39
- the volume of blood in ventricles at the end of diastole
- end diastolic volume
preload
40
- 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)
41
The pressure needed to open the aortic valve
afterload
42
The inherent rhythmicity of the heart can be overridden by the _
cardiovascular control center (CVC)
43
sympathetic innervation of the heart leads to _ and _
- increased rate
- increased force of contraction
44
- 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
45
Peripheral input sends messages relating to _
- pressure
- tension
- movement
46
excess calcium causes _
spastic contractions of the heart
47
cortical input can impact the heart via _
emotions
48
During resistance training blood pressure _
Systolic BP and Diastolic BP increase
49
- 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
50
The most important criteria for the CV system during exercise is _
maintain blood pressure
51
The trachea moves debris similarly to a _
blow gun
52
_ is matched to the volume of air demonstrated by submarine volume changes
volume in an alveoli
53
as you begin to inhale, the pressure in the alveoli is _
negative
54
Exhalation is _ at rest
passive
55
the surface area of alveoli is the size of _
a tennis court
56
when someone has restrictive lung disease (RLD) _ is restricted
inhalation
57
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
58
The _ ventricle is thicker than the _ ventricle
Left is thicker than Right
59
after leaving the Bundle of HIS, the electrical signal travels down the _
RBB and LBB to the perkinjie fibers
60
depolarization of cardiac muscle is _
fast
61
_ goes up more during resistance training than it does during aerobic training
systolic blood pressure (SBP)
62
_ decreases to a similar degree as systolic blood pressure during an aerobic bout
diastolic blood pressure (DPB)
63
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
64
Blood pressure can be lower than pre-exercise for _ post an aerobic bout
2-3 hours
65
During an aerobic bout, the heart will use _ primarily for its energy source
lactate
66
_ input exerts lesser influence on blood flow during exercise than _ input
- parasympathetic
- sympathetic
67
as total peripheral resistance goes up, _ also increases
blood pressure
68
During exercise: at the _ there is significant _ in blood volume delivered to the working muscle
- local level
- increase
69
During exercise: at the _ there is NOT significant increase in the velocity of blood flow to the tissues
local level
70
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
71
Major lung properties _
- dry
- inflated
72
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
73
Purpose of _
- prevent spread of infection
- prevent complete obstruction from an inflated foreign body
lung segments
74
segmental anatomy:
redundancy
75
Lobe segments ( _ total):
20 total
- upper
- middle
- lower
76
- 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
77
_ zone
- air adjusts to body temperature, filtered and almost completely humidified
- includes: trachea, bronchi, bronchioles
- has cartilage, lower do not, interdependent
conducting zone
78
conducting zone also termed _ due to containing no alveoli
anatomic dead space
79
_ zones
- contains: bronchioles, alveolar ducts, alveoli
- occupies about 2.5-3L
- is the largest portion of total lung volume
transitional and respiratory zones
80
_ zone is where gas exchange occurs
respiratory zone
81
_ zone functions:
- air transport
- humidification
- warming
- particle filtration
- vocalization
- immunoglobulin secretion
conducting zone
82
_ zone functions:
- surfactant production (in alveolar endothelium)
- molecular activation and inactivation (in alveolar endothelium)
- blood clotting regulation
- endocrine function
respiratory zone
83
air is distributed in proportion to _
segmental volume
84
ventilation is matched to volume:
regional ventilation = regional volume
85
_ : branch point of the lungs
- bronchiole tree is not symmetrical
carina
86
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
87
_ : rigid, cartilaginous box
- narrowest part of the system
- "V" is front: vocal cords
- vocal cords move in synchrony with diaphragm
larynx
88
_ : ~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
89
_ : large, dome-shaped sheet of striated musculofibrous tissue
- primary ventilatory muscle which creates an airtight separation between abdominal and thoracic cavities
diaphragm
90
membrane is responsible for almost all respiratory muscles shortening and volume displacement
diaphragm
91
diaphragm _, _, and _
- contracts
- flattens
- and moves downward toward abdominal cavity (up to 10cm)
92
elongation and enlargement of chest cavity expands the air in the lungs _ decreases
intrapulmonic pressure (IP)
93
with a drop in intrapulmonic pressure (IP), pressure in lungs is _
lower than atmospheric pressure
94
degree to which lungs fill is determined by the _ of the inspiratory movement
magnitude
95
maximal activation of the inspiratory muscles in a healthy individual ranges from _
80-140 mm Hg
96
inspiration ends when _
thoracic cavity stops
97
(inspiration) stop in thoracic movement means there is a same pressure in lungs (IP) as _ pressure
ambient atmospheric
98
during exercise: a need for more efficient movements of the diaphragm, rib cages, and abdominal muscles
inspiration in exercise
99
during _, the saleni and external intercostal muscles contract, causing the ribs to rotate and lifting a handle up from a bucket
inspiration
100
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
101
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
102
2 factors of expiration:
1. Natural recoil of the stretched lung tissue
2. Relaxation of the inspiratory muscles
103
During expiration, ribs _, and diaphragm _
- ribs swing down (bucket handles)
- diaphragm rises toward the thoracic cavity
104
Expiration ends when compressive force of the expiratory musculature ends and intrapulmonic pressure (IP) _
decreases back down to atmospheric pressure
105
muscles of expiration
(intercostals are stabilization)
(usually passive)
- rectus abdominus
- obliques
- lats
106
chronic obstructive pulmonary disease
- mismatch between ventilation and perfusion
COPD
107
restrictive lung disease
- inhalation is restricted
- more work to breath
RLD
108
air moves across a _
pressure gradient
109
Flow in lungs is _, not turbulent, difficult to _
- swirly
- characterize the flow in upper airways
110
Flow in lungs - assume Ohms law:
Resistance (R) = change pressure/flow or flow = change in pressure/R
111
V = flow/area
velocity
112
- 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
113
Disease states: (obstructive airway disease)
greater pressure for adequate flow
114
Delta Vt/Delta pressure =
compliance
115
high compliance:
Emphysema
116
with increased pressure
- _ chest wall diameter
- _ abdominal space
- increase
- compress
117
alveoli are connected via smooth muscle and connective tissue: one opens, all open to _
prevent atelectasis
118
similar to flypaper, lubricates, and protects
- hydrates
- provides protective surface
- collect debris
mucosal clearance
119
Goblet cells secrete _
sticky, tenacious mucous
120
submucosal glands are _, makes islands
less sticky
121
debris is moved up on islands to carinas via _
- clean from periphery to the central
- mucocilliary escalator
cilia "beating"
122
does not regulate soluble phase
- cilia are too deep, below the surface, cannot beat effectively, bacteria can overgrow
cystic fibrosis
123
peripheral airways have laminar (straight) flow, allows _
for diffusion
124
alveoli have pores for _, collateral airflow
gas diffusion
125
volume moved during either an inspiratory or expiratory phase of each breath (L)
Tidal volume (Vt)
126
- reserve ability for inspiration (L)
- volume of extra air that can be inhaled after a normal inhalation (L)
inspiratory reserve volume (IRV)
127
volume of extra air that can be exhaled after a normal exhalation (L)
expiratory reserve volume (ERV)
128
- volume of air remaining in lungs following a maximal exhalation (L)
- usually increases with age
- allows for uninterrupted exchange of gases
Residual volume (RV)
129
- volume of air in the lungs at the end of a normal tidal exhalation (end tidal) (L)
functional residual capacity (FRC)
130
functional residual capacity is important for _
maintaining gas pressures in the alveoli
131
_ determined by:
- height, weight, age, gender
- compliance
- surfactant
- inspiration/expiration muscle strength
- maximal amount of air in the lungs
total lung capacity (TLC)
132
RV + VC =
TLC
133
maximal amount of air that can be moved in one minute (L/min)
maximal ventilatory volume (MMV or MBC)
134
2 types of ventilation
1. pulmonary
2. alveolar
135
_ type of ventilation:
- air is brought into lungs and exchanged with air in lungs (Ve)
pulmonary
136
_ type of ventilation:
- exchange of gases between alveoli and capillaries
alveolar
137
- 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
138
_ of _ tidal volume will enter into and mix with existing alveolar air
350 ml of 500 ml
139
_ 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
140
anatomic dead space _ with increase in _
- increases
- tidal volume
141
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
142
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
143
with light exercise,
V/Q is maintained
144
Disproportionate increase in alveolar ventilation
with heavy exercise
145
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
146
Portion of alveolar volume with poor V/Q ratio is _
- small in healthy lung
physiologic dead space
147
if physiologic dead space is >60% of lung volume, adequate gas exchange is _
impossible
148
- spirometry (cannot determine RV and FRC)
- helium diffusion
- oxygen washout
- plethysmograph (in lab)
techniques of assessing lung volumes
149
plethysmograph based on
Boyle's Law : P1V1 = P2V2
150
Rate of gas diffusion depends on two factors:
1. pressure differential between gas above the fluid and gas dissolved in the fluid
2. Solubility of the gas in the fluid
151
in humans: pressure difference between alveolar and pulmonary blood creates the driving force for _ across the _
- gas diffusion
- pulmonary membrane
152
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
153
_ 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
154
exchange of gases between the lungs and blood, and gas movement at the _ progress _ by diffusion, depending on their pressure gradients
- tissue level
- passively
155
- > 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
156
during alveolar ventilation: at rest, _ O2 leave alveoli in blood, and _ CO2 diffuse into alveoli
- 250 ml
- 200 ml
157
during heavy exercise, (TR athletes) _ in quality of O2 transfer
25x increase
158
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
159
- 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
160
partial pressure is noted by _
Ex: PO2 = 159
P in front
161
- 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
162
- 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
163
-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
164
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
165
- CO2 pressure gradient is smaller, ~ 6 mm Hg
- adequate gas exchange still occurs because of _ of CO2
high solubility
166
Nitrogen is _ or _ in gas transfer in the lungs
- _ is relatively unchanged
- not used or produced
- Partial pressure Nitrogen (PN)
167
_ is rapid during gas transfer in lungs, ~ 1 sec, midpoint of blood's transit through the lungs
equilibrium
168
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
169
Gas transfer in lungs:
- at rest, the pressure of oxygen molecules in blood exceeds oxygen pressure in the _ (60 mm Hg)
alveoli
170
Gas transfer in lungs:
- oxygen diffuses through the _ into the blood
alveolar membrane
171
Gas transfer in lungs:
- carbon dioxide transfer occurs _ because of _ in plasma
- rapidly
- high solubility
172
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
173
at high intense exercise, _ of RBC does not exceed by more than 50% of _
- velocity
- resting velocity
174
with increasing intensity, pulmonary capillaries increase blood volume _
3x rest
175
- 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
176
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
177
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
178
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
179
Gas transfer in tissues:
- _ is critical for chemical input for control of breathing (respiratory center in brain)
PCO2
180
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
181
_ meets metabolic demands constantly
alveolar ventilation
182
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
183
Gas transfer in tissues:
- blood carries oxygen in two ways
1. in physical solution dissolved in the fluid portion of blood
2. loose combination with hemoglobin
184
- 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
185
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
186
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
187
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)
188
Gas transfer in tissues:
- plasma PO2 determines _ at the lungs (oxygenation) and its _ at the tissues (deoxygenation)
- the loading of hemoglobin
- unloading
189
- decrease in iron content of RBC will reduce blood's oxygen-carrying capacity
- lower hemoglobin concentration impairs aerobic exercise performacne
iron deficiency anemia
190
- 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
191
- 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
192
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
193
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
194
- 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
195
gas transfer in tissues:
- blood carries CO2 in 3 ways:
1. physical solution in plasma
2. combined with hemoglobin with RBC
3. as plasma bicarbonate
196
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
197
CO2 gas transfer in tissues:
- majority of CO2 transported during chemical reaction with water to form _
- 60-80%
- plasma bicarbonate
- bicarbonate
198
CO2 gas transfer in tissues:
- about 20% of the body's CO2 combines with blood proteins including hemoglobin to form _
carbamino compounds
199
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
200
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
201
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
202
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
203
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
204
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
205
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
206
_ 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
207
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
208
_ in the tissues:
- differences in O2 content in arterial and mixed venous blood is the _ or the (a-v)O2 difference
- PO2
- arteriovenous difference
209
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
210
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
211
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%
212
_ 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
213
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
214
- 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
215
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
216
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
217
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
218
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
219
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
220
Control of _ during exercise:
- humoral stimuli
- neural stimuli
ventilation
221
control of ventilation during exercise:
- changes in physical and chemical properties in blood from normal values at rest
humoral stimuli
222
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
223
- 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
224
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
225
- hiccups can last a few seconds to a few hours
- seek medical attention after 3 hours
- can effect sleeping patterns
hiccup timeline
226
- 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
227
- increased pulmonary ventilation that exceeds gas exchange needs for metabolism
- also termed "over breathing"
- causes lower concentration of CO2
hyperventilation
228
- 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
229
- 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
230
- 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
231
- 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
232
- 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
233
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
234
average fitness level hearts at _ exceeds in one minute the fluid output of a household faucet turned wide open
max output
235
Heart connected by _ that allows chemical and electrical coupling between cells
intercalated disks
236
Heart pump:
_ side:
- receive blood returning from throughout the body
- pump blood to the lungs for aeration through the pulmonary circulation
right
237
Heart pump:
_ side:
- receive oxygenated blood from the lungs
- pump blood into thick-walled, muscular aorta for distribution throughout body in systemic circulation
left
238
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
239
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
240
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
241
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
242
Valves in the heart:
- between right ventricle and pulmonary artery is a semilunar valve (three cusps) also called _
pulmonic valve
243
Valves in the heart:
- between left ventricle and aorta are _ (prevents backflow of blood from aorta into the heart)
semilunar valve
244
Blood flow through the heart:
- step one: blood flows into _
right atrium from superior and inferior vena cava
245
Blood flow through the heart:
- step two: blood travels from _
R atrium into R ventricle
246
Blood flow through the heart:
- step three: blood flows through _
pulmonary artery into the lungs (for oxygenation)
247
Blood flow through the heart:
- step four: blood returns from the _
lungs through the pulmonary veins, and is deposited into L atrium
248
Blood flow through the heart:
- step five: from L atrium, blood flows into _
L ventricle
249
Blood flow through the heart:
- step six: blood leaves _
L ventricle via aorta, enters general systemic circulation
250
Heart has _ rhythmicity
intrinsic
251
Flow of electricity through the heart:
- step one: originates in _
Sinoatrial node (SA node), superior, lateral aspect of R atrium
252
Flow of electricity through the heart:
- step two: travels through _
both atria to atrioventricular node (AV node), this causes depolarization of atria
253
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)
254
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
255
ventricles have a powerful contraction, and provide the major impetus to _ throughout the CV system
more blood
256
_ 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
257
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
258
action potential is caused by the opening of two types of channels:
1. fast sodium channels allow the sodium ions to enter the cell
2. 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)
259
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
260
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
261
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
262
- 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
263
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
264
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
265
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
266
- volume in ventricles after the period of filling
- usually ~ 110-120 ml of blood/ventricle
end diastolic volume (EDV)
267
- volume ejected during systole
- ~70 ml
stroke volume (SV)
268
- volume in ventricles after systole
- ~40-50 ml
end systolic volume (ESV)
269
- 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
270
Volume pressure curves for systole and diastole:
- phase _: filling phase ESV to EDV increase volume ~70% ml, pressure rises ~5 mm Hg (diastolic)
1
271
Volume pressure curves for systole and diastole:
- phase _: isovolumic contraction, increase pressure (~80 mm Hg), not volume
2
272
Volume pressure curves for systole and diastole:
- phase _: ejection period
3
273
Volume pressure curves for systole and diastole:
- phase _: isovolumic relaxation ventricle pressure decreases to diastolic levels
4
274
_ in the cardiovascular system
- degree of tension on the heart muscle when it begin to contract
preload
275
_ in the cardiovascular system
- load against which the muscle exerts its contractile force
- pressure in artery leading away from the ventricles
afterload
276
- 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
277
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
278
central control center provides the greatest control over _ during exercise
heart rate
279
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
280
_ 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
281
_ 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
282
Inhibition of sympathetic nervous system can _
decrease heart rate and pumping
283
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
284
_ 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
285
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
286
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
287
_ 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
288
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
289
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
290
_ input:
- impulses from cerebral cortex pass via afferent nerves through CVC in medulla
- allows emotional state to influence _
- cortical
- CV response
291
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
292
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
293
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
294
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
295
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
296
Heart as pump:
- Two factors that influence delta P / delta t which are NOT related to cardiac contractility are:
1. increased input pressure to the L ventricle (EDV, Preload)
2. pressure in the aorta, afterload
297
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
298
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
299
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
300
- 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
301
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
302
Blood transport:
- _: smooth muscle; can constrict and dilate dependent on peripheral blood needs
- metarteries are less muscular
arterioles
303
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
304
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
305
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
306
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
307
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
308
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
1. flap-like valves (one-way) at short intervals in veins
2. valves are easily compressed by neighboring muscles
309
_: due to hardening of arteries, excessive peripheral resistance
- enhanced nervous tone or kidney malfunction
hypertension
310
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
311
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
312
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
313
BP and resistance training:
- _: pinch your nose, close mouth, try to exhale, or bear down, 10-15 seconds -- pop your ears
valsalva
314
BP and resistance training:
- 4 phases to relax heart's electrical system:
1. pressure rises in chest and belly
2. heart pumps less blood
3. relax- HR increases
4. recovery
315
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
316
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
317
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
318
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
319
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
320
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
321
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
1. increased myocardial metabolism causes dilation of coronary vessels
2. increased aortic pressure forces a larger amount of blood into coronary circulation
322
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
323
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
324
_: 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
325
- also called the double product: _
- highly related to _ oxygen consumption and _
- RPP = _
- rate-pressure product
- myocardial
- coronary blood flow
- SBP x HR
326
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)
327
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
328
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
329
- 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
330
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
331
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
332
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
333
Neural factors:
- central regulation ensures that the area with the most need for _ gets the most _
- oxygen
- blood flow
334
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
335
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
336
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
337
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
338
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
339
Integrated response in exercise:
- 3 factors influencing venous return:
1. action of muscle and ventilatory pumps
2. stiffening of veins
3. increase in venous tone with an increase in Q
340
Cardiac output:
- Q = _
- primary indicator of the _ to meet the demands of Pa
- HR x SV
- functional capacity of the circulation
341
1. indirect fick
2. indirect dilution
3. CO2 rebreathing, indirect fick
4. impedence
four methods to determine Q
342
Method for determining Q:
- 1. _
- Q =Q2 consumed / (a-v)O2
direct fick
343
Method for determining Q:
- 2. _
- examin an indicator dilution curve (not as accurate)
indirect dilution
344
Method for determining Q:
- 3. _
- Q = CO2 production / (v-a)CO2 x 100
CO2 rebreathing, indirect fick
345
Method for determining Q:
- 4. _
- SV
- preload
- afterload
- contractility
- BP
- systemic vascular resistance (SVR)
- can index the values to body size
impedence
346
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
347
Cardiovascular responses to exercise:
- increased skin _
remove heat
blood flow
348
Cardiovascular responses to exercise:
- decreased blood flow to _
- decreased urinary output and maintenance of blood volume
- decreased _ flow
- reduced GI activity
- kidneys
- visceral
349
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
350
Cardiovascular regulation directed to _
- balance between maintaining BP and need for more blood to active tissue
maintain blood pressure
351
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
352
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
353
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
354
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
