FINAL Flashcards
Systole
Contraction of atriums
Eject blood
Diastole
relaxation of heart
what happens in systole
ventricles contract
tricuspid/mitral valves close
what happens in diastole
ventricle relax and fill with blood
av valves open
ECG
electrocardiogram
P phase of EKG
atrial depolarization
SA node
sinoatrial node
- pacemaker of heart
- sets heartbeat
- located in right atrium
- causes atria to contract
QRS phase of ECG
ventricular depolarization and arterial repolarization
T phase of EKG
ventricular repolarization
AV node
atrioventricular node
- b/w right atrium + ventricle
- electrical impulses spread to ventricles during heartbeat
bundle branches
messages travel through these to septums of heart
perjunke fibers
on outer walls of ventricles
- allow for depolarization of ventricular tissues
graph HR , SV, CO in response to incremental exercise
HR : increases linearly toward max
SV : increases and then plateus
40-60% VO2 max (no plateu in trained ppl)
CO: increases linearly
how do parasympathetic factors regulate HR during exercise
decreases HR by inhibiting SA + AV nodes
- vagus nerve
how do sympathetic factors regulate HR during exercise
increases HR by stimulating SA and AV nodes
- cardiac accelerator nerve
what factors affect SV during exercise
end diastolic volume, strength of contraction
end diastolic volume
volume of blood in each ventricle at end of diastole
how does exercise influence venous return
- venoconstriction
- muscle pump : rhythmic skeletel muscle contractions force blood in extremities toward heart
- respiratory pump : changes in thoracic pressure pull blood toward heart
- change in pressure : difference b/w MAP and right atrial pressure
Venoconstriction
under sympathetic control pushes blood toward heart
what factos determine blood flow during exercise
- skeletal muscle vasodilation
- increases artery resistance
- decreased blood flow to tissues
changes that occur to HR in a hot environment
increase
changes that occur to SV in a hot environment
decrease
changes that occur to CO in a hot environment
increase
HR during prolonged exercise
gradual increase toward max
SV during prolonged exercise
gradual decrease due to dehydration
reduced plasma volume
CO during prolonged exercise
maintained at high level
Compare heart rate and blood pressure responses to arm and leg work at the same oxygen uptake. What factors might explain the observed differences?
both HR and blood pressure increase higher during an arm workout compared to leg
- HR Due to higher sympathetic stimulation
-BP Due to vasoconstriction of large inactive muscle mass
Capillaries
Microscopic vessel through which exchanges take place between the blood and cells of the body
deoxygenated blood flow
- From the body
- Superior & inferior vena cava
- Right atrium
- Tricuspid valve
- Right ventricle
- Pulmonary artery (to lungs for O2/CO2 exchange)
oxygenated blood flow
- Pulmonary vein (from lungs to get O2)
- Left atrium
- Bicuspid (mitral) valve
- Left ventricle
- Aorta
- To body
Myocardium
muscular, middle layer of the heart
myocardial infarction (MI)
Heart Attack; due to blockage in coronary blood flow preventing the O2 supply resulting in cell damage
Cardiac Output
The volume of blood ejected from the left side of the heart in one minute
Cardiac Output equation
HR x SV
What happens to CO during exercise
increases
Qmax determined by
body size and aerobic fitness
What happens to HR during exercise
increases
Maximum HR
highest HR achieved in all-out effort to volitional fatigue
Maximum HR equation
220-age
Stroke Volume (SV)
The volume of blood pumped forward with each ventricular contraction
What happens to SV during exercise
increase until about 40-60% then plateaus
During Max exercise how does a trained individual differ
A trained individual will have a higher CO, SV, and lower HR
Pulse Pressure
the difference between systolic and diastolic blood pressure
Mean Arterial Pressure (MAP)
time averaged pressure in arteries
MAP equation
DBP+0.33(SBP-DBP)
Hypertension
higher than normal blood pressure
Short term BP regulation
sympathetic nervous system and baroreceptors
increase in BP=
decreased SNS activity
decrease in BP=
increased SNS activity
long term BP regulation
Mostly controlled by kidneys via control of blood volume by hormones
RAAS (renin-angiotensin-aldosterone system)
Renin is released by kidneys in response to decreased blood volume & maintains blood pressure
Changes in BP during exercise
SBP increases linearly
DBP remains fairly constant
MAP increases linearly
Ejection Fraction (EF) equation
EF = SV/EDV
Partial Pressure equation
Blood Flow = P1-P2/Resistance
Frank-Starling Mechanism
A mechanism by which the stroke volume of the heart is increased by increasing the venous return of the heart (thus stretching the ventricular muscle)
Baroreceptors
detect changes in blood pressure
primary function of pulmonary system
exchange of gases between the environmental air and blood
secondary function of pulmonary system
plays an important role in the regulation of the acid-base balance during exercise
major anatomical components of pulmonary system
lungs, diaphragm, larynx & pharynx, nasal cavity, trachea, bronchial tree
Respiration
exchange of gas molecules through a membrane or liquid
Ventilation
movement of air in and out of the lungs
Diffusion
Movement of molecules from an area of higher concentration to an area of lower concentration
conducting zone
conducts air to respiratory zone, humidifies, warms, and filters air
components of conducting zone
trachea, bronchial tree, bronchioles
Respiratory Zone
exchange of gases between air and blood
components of respiratory zone
respiratory bronchioles and alveolar sacs
Ventilation/Perfusion Ratio (V/Q)
the ratio between ventilation and perfusion in the lung; matching of ventilation to perfusion optimizes gas exchange
Heavy exercise results in V/Q inequality (Ventilation becomes higher and blood flow also increases)
Ventilation becomes higher and blood flow also increases
sickle cell anemia
a genetic disorder that causes abnormal hemoglobin, resulting in some red blood cells assuming an abnormal sickle shape
Light exercise improves
V/Q (moves closer to 1.0)
Overperfusion to
base of lungs
Underperfusion to
apex of lungs
Ficks law
law stating that the net diffusion rate of a gas across a fluid membrane is proportional to the difference in partial pressure, proportional to the area of the membrane, and inversely proportional to the thickness of the membrane
Factors that influence the rate of diffusion across blood-gas interface in the lung
Volume of gas area for diffusion
Difference in Partial Pressure
Membrane thickness
the greater the difference in partial pressure
the greater rate of diffusion
the thinner the membrane
the higher the diffusion
Dalton’s Law
at constant volume and temperature, the total pressure exerted by a mixture of gases is equal to the sum of the partial pressures of the component gases
Chronic Obstructive Lung Disease (COPD)
Increased airway resistance
Due to Constant airway narrowing
Decreased expiratory airflow
Intrapulmonic pressure & Atmospheric Pressure
760 mmhg
Intrapleural Pressure
756 mm Hg
Pulmonary Ventilation
The amount of air moved in and out of the lungs per minutes (V)
Tidal Volume (Vt)
Amount of air that moves in and out of the lungs during a normal breath
breathing frequency (f)
number of breaths taken per minute
Alveolar Ventilation (Va)
Volume of air that reaches the respiratory zone
Dead Space Ventilation (VD)
Volume of air remaining in conducting airways
V = Va+Vd or V= Vt x f
Ventilation Equation
spirometry
a measurement of breathing
Vital Capacity (VC):
Maximal volume of air that can be expired after maximal expiration
Forced Expiratory volume (FEV1)
Volume of air expired in 1 seconds during maximal expiration
FEV1/VC ratio
≥ to 80% is normal
Airflow depends on
Pressure difference between two ends of the airway
Resistance of airways
The relationship between hemoglobin-O2 saturation and the partial pressure of O2 in the blood
hift of the graph to the right means lower saturation for given PaO2 . Shift of the graph to the left means higher saturation for given PaO2
What is the functional significance of the shape of the O2-hemoglobin dissociation curve?
The curve describes the non-linear tendency for oxygen to bind to hemoglobin
What factors affect the shape of the curve?
Ph and temp
Discuss the modes of transportation for CO2 in the blood
- 70% through bicarbonate
- 20 % bound of Hb
- 10% dissolved in plasma
Chronic Bronchitis
- Excessive mucus blocks airway
Emphysema
Airway collapse and increases resistance
Calculation of partial pressure
P air= PO2+PCO2+PN2
% of O2 in air
20.93%
% of CO2 in air
0.03
% of N2 in air
79.04 %
Oxygen is transported
via hemoglobin or dissolved in the blood
Each HB can transport
1.34ml O2
The ventilatory response in the transition from rest to constant-load submaximal exercise
ventilation increases rapidly, then a slower rise toward steady state. PO2 and PCO2 are relatively unchanged. PO2 has slight decrease and PCO2 has slight increase
What happens to ventilation if the exercise is prolonged and performed in a hot/humid environment?
drift upward because increased blood temp. affects respiratory control center. Higher ventilation not due to increased PCO2
Oxyhemoglobin Dissociation Curve
Direction of reaction depends on
the partial pressure of oxygen in the blood
Affinity (attraction to each other) between Hb and O2
Decreased pH=
= more acidic= right shift
Increased pH=
= more basic= left shift
Increase in body temp=
shift to the right
Drop in body temp
shift to left
2,3 DPG (diphosphoglycerate)
When levels are increased =
right shift of the curve
2,3 DPG (diphosphoglycerate)
When levels are decreased =
left shift of the curve
Myoglobin
stores oxygen in muscle cells
Myoglobin action
Shuttles O2 from the cell membrane to the mitochondria
Mb has a ________ affinity for O2 than hemoglobin
higher
Function of Central chemoreceptors in the medulla
regulates H+ and PCO2 concentration in cerebrospinalfluid
Function of Peripheral chemoreceptors in aortic and carotid bodies
regulates PO2, PCO2, K+, and H+ in blood
Oxyhemoglobin
hemoglobin bound to oxygen
The control of ventilation during exercise
- Primary drive by higher brain centers
- “Fine tuned” by humoral chemoreceptors and neural feedback from muscles
Deoxyhemoglobin
hemoglobin without oxygen
Central Command Theory
initial signal to “drive” cardiovascular system comes from higher brain centers
Ventilary Control during exercise
Increase in ventilation, anticipatory response due to input from central command
Untrained Individuals Ve
Linear increase up to 50-70% VO2 max, exponential increase beyond this point
Trained Individuals Ve
Occurs at higher % VO2 max, because of delayed anerobic threshold
ventilatory threshold
the point where ventilation increases at a non-linear rate
hypoexmia
very low level of oxygen in the arterial blood
