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Section 3

Terms in this set (77)

What is the anatomy of the heart?
-4 chambers
-Valves separating chambers
-Right side: pulmonary circuit
-L side: systemic circuit
What are the 4 functions of the cardiovascular function?
-Deliver oxygen
-Deliver nutrients
-Remove waste
-Regulate temp
What are the 2 major adjustments of exercise?
-Cardiac output
-Blood flow distribution
What type of system is the cardiovascular system?
-Closed system
-Arteries to vevins
What are the 3 layers of myocardium?
-Epi, myo, and endocardium
What are the similarities of myocardium and skeletal muscle?
-Striated tissue
-Contractile process
What are the unique aspects of myocardium?
-Short, branched fibers
-Intercalated disc connection
-Highly aerobic fibers, large number of mitochondria
How does pressure change?
-Pressure dictates flow, opening and of closing of valves
What are the values for normal blood pressure (male and female)? What are the values for High BP?
-Male: 120-80
-Female: 110/70
-BP: 140/90
What factors influence Blood Pressure?
-Blood volume increases
-Heart rate increases
-Stroke volume increases
-Blood viscosity increases
-Peripheral resistance increases
What are the characteristics of the electrical conduction of the heart?
-Specialized, autorythmic cells
-Na influx
-SA and AV nodes, bundle branches, purkinje fibers
What is the equation of Cardiac Output?
Q = SV x HR
What factors affect cardiac output?
-Preload
-Afterload
-Contractility
-Heart rate
What is the cardiac output at rest? Max ex?
-Rest: 51/min
-Max ex: 25 l/min
How does pre sympathetic affect heart rate?
-Negative
-Vegus nerves and nodes
How does sympathetic affect heart rate?
-Positive
-Cardiac accelerator nerves, nodes and ventricles
What alters heart rate?
-Parasympathetic withdrawal
-Sympathetic output
What is EDV? Define Preload
-End-diastolic volume
-Preload: volume of blood in the ventricles and the end of diastole
Define Afterload
Pressure the heart must pump against to eject blood
Define contractility
Strenght of the ventricular contraction
What is the equation for preload?
-Increased EDV = Increased Ventricular Strength + Increased SV
What 3 factors influence End Diastolic Volume?
1. Vasoconstriction
2. Muscle Pump
3. Respiratory pump
What is vasoconstriction?
-Sympathetic output
-Smooth muscle contraction
What is a muscle pump?
-Muscle contraction and compression of veins
What is the respiratory pmp?
-Increased abdominal pressure (inspiration)
What is the acronym for TPR?
Total peripheral resistance
What is the equation for increased Q?
^EDV + ^Ca = ^Q
What occurs to increase Intracellular Ca?
-Sympathetic output to myocardium
-Circulating epinephrine
What factors regulate Q?
-Q=CRxSV
-Cardiac (pre sympathetic nerves) Rate (sympathetic nerves)
-Stroke (contraction strength)
What are the physical characteristics of blood?
-RBC
-WBC
-Platelets
-Hematocrit
-Viscosity
What factors effect blood flow?
-Pressure gradient
-Factors:
a. Vessel diameter
b. Blood viscosity
What is Poiseuille's Equation?
F=(P1-P2){pie}R^4/8LN
-Flow
-Pressure
-Radius
-Vessel length
-Viscosity
Describe Poiseuille's Equation in words?
Small change in diameter = large change in blood flow
How is oxygen demand affected by exercise?
Oxygen demand by muscles increases during exercise
What is increased O2 delivery during exercise accomplished by?
-Increased Cardiac Output
-Redistribution of blood flow to skeletal muscle
What is the redistribution of blood flow like during exercise?
-Muscle blood flow increases to working skeletal muscle
-Flow to gut decreases to less organs (kidneys, GI tract)
Define autoregulation
-Local override of sympathetic output
-Local vasodilation
What are the activators (that signal what parts of the body need more blood during exercise)?
-Nitric Oxide
-Adenosine
-PO2
-PCO2
-pH
Where is the cardiovascular control center located?
Medulla and pons (aka brainstem)
How does the brainstem regulate the cardiovascular response?
Receives input from central command and several afferents
What is the acronym for CVC? What is its function?
-Cardiovascular control center
-Higher brain centers associated with motor output are routed through the CVC
What signals do the brainstem and CVC send at onset and during exercise?
-Vasoconstriction
-Increased HR
-Increased contraction force
What does the hypothalamus regulate?
Temperature
What does the baroreceptor regulate?
Pressure
What are the 2 chemoreceptors? What do they detect changes in?
-Carotid bodies and Aortic bodies
-CO2, pH, O2
What are 3 contributing factors to muscle afferent?
-Mechanical
-Thermal
-Chemical
What are the 3 functions of the lungs?
-Ventilation
-Respiration
-Diffusion
What is the function of the conducting zone?
Conducts air to respiratory zone
What is the result of the conducting zone?
Humidifies, warms, and filters air
What are the components of the conducting zone?
-Trachea
-Bronchial Tree
-Bronchioles
What is the function of the respiratory zone?
Exchange of gases between air and blood
What are the components of the respiratory zone?
-Respiratory bronchioles
-Alveolar sacs
What occurs during inspiration?
Diaphragm pulls downward, lowering intrapulmonary pressure
What occurs during expiration?
Diaphragm relaxes, raising intrapulmonary pressure
What is resistance to airflow determined by?
Airway diameter
Define pulmonary ventilation
The amount of air moved in or out of the lungs per minute
What is the equation for Pulmonary Ventilation?
Ve= Vt x fb
(Ve: pulmonary ventilation)
(Vt: tidal volume)
(fb: breathing frequency)
What does Dalton's law state?
The total pressure of a gas mixture is equal to the sum of the pressure that each gas would exert independently
What is the partial pressure of oxygen (PO2)? Of CO2? N2?
-O2 = 20%
-CO2 = ~1%
-N2 = 79%
What is pulmonary diffusion?
Gas exchange at the lungs ()2 uptake, CO2 removal)
What is the pulmonary membrane's composition?
-Alveolar/capillary wall
-Fluid spaces
What is the function of gradients?
-Diffusion
-"Push"
-Steep and shallow
How does partial pressure vary throughout the body?
-O2 present=high PO2
-O2 use=lower PO2
What is Hemoglobins affinity for O2?
-High affinity
-99% of O2 transported is bound to hemoglobin
How is blood pH affected by exercise?
-Blood pH declines during heavy exercise
How does temperature affect the Hb-O2 bond?
Increased blood temp results in a weaker Hb-O2 bond
What is myoglobin?
-Helps to transport O2 in muscle
-Binds O2 in the muscle
Is the affinity for O2 greater for myoglobin or hemoglobin?
Hemoglobin
What type of muscle fiber has the greatest concentration of myoglobin?
-Greater concentration in type 1 muscle tissue
Which is more soluble-CO2 or O2?
CO2
What is the equation for Bicarbonate?
CO2 + H2O <-> H2CO3 <-> H + HCO3
What is the Respiratory Control Center's role in control of ventilation?
Initial stimulus
What is the Chemoreceptor's role in control of ventilation?
-Central (medulla)
-Peripheral (aortic, carotid)
What is the Neural Input's role in control of ventilation?
-Skeletal muscle (mechanoreceptors and chemoreceptors)
Is it likely that respiratory muscle fatigue will affect performance?
Unlikely
What is the result of exercise induced by hypoxemia?
-Desaturation at high intensity exercise
-Blood flow (Q) exceed pulmonary diffusion capacity
What are the 3 ways CO2 can be transported?
-Dissolved
-Hemoglobin
-Bicarbonate (main)
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