Blood Circulation Flashcards
transport substances in all the exchange surfaces within the animal
Circulatory system
W hat are 2 types of circulatory systems
Open and closed circulatory systems
Parts of Circulatory system (4)
Propulsive organ
Arterial system
Capillaries
Venous system
Pumps blood around the body
Propulsive organ
Distribution of blood and pressure resevoir
Arterial System
Sites of transfer of substances from blood to tissues and vice versa
Capillaries
Blood reservoir, system for returning blood to the heart
Venous system
Arteries, capillaries, and veins constitute the??
Peripheral circulation system
What causes the blood to flow?
- Rhythmic contractions of the heart
- Recoil of arteries
- Body movements
- Contractions of smooth muscle
receive blood from circulation
Atrium
pumps blood to blood vessels
Ventricle
brings blood AWAY from the heart
Usually contain oxygenated blood
Artery
Leads to capillaries
Arteriole
Where exchange of substances takes place
Capillary
Leads to vein
Venules
Brings blood TO the heart, usually contains deoxygenated blood
Vein
These are the only caveats to the oxygenation and deoxygenation rule
Pulmonary vein (Oxygenated) and arteries (Deoxygenated)
Two states of the cardiac cycle
Systole (Contraction)
Diastole (Relaxation)
Initiates electrical activity in the heart
Pacemaker
Two types of pacemakers and where they can be found
Neurogenic - Invertebrates
Myogenic - Vertebrates and some invertebrates
summation of the electrical activity in various parts of the heart
Electrocardiogram (ECG)
Major components of the ECG
P Wave
QRS Wave
T Wave
What do the different components of the electrocardiogram mean?
P – atrial depolarization
QRS – ventricular depolarization
T – ventricular repolarization
Path of the spread of cardiac excitation in mammalian heart
SA Node -> AV Node -> Bundle of His -> Purkinje Fibers
heart beat per minute
Heart rate
Amount of blood pumped out by each ventricle during each beat
Stroke Volume
Factors affecting Heart Rate
Sympathetic and parasympathetic activity
Parasympathetic stimulation _____ cardiac output
Reduces
ACh decreases heart rate, excitability of the AV Node, and shortens the action potential
Sympathetic stimulation _____ cardiac output
Increases
Norepinephrine increases heart rate, reduces the AV nodal delay, speeds up the spread of the action potential, and increases contractile strength
Factors Affecting Stroke Volume
Intrinsic control – venous return
Extrinsic control – sympathetic stimulation
increase stroke volume by increasing the strength of contraction of the heart
States that the greater the volume of blood filling the heart during diastole (relaxation), the more forcefully the heart contracts during systole (contraction), leading to an increased stroke volume and cardiac output.
Frank-Starling Law of the Heart
layers of the fluid slide smoothly over each other - characterized by a parabolic velocity profile across the vessel
Laminar Flow
fluid moves in directions not aligned with the axis of the flow - increase in the energy needed to move fluid through a vessel
Turbulent Flow
Hemodynamic flow law
Q = ΔP/R
Q = flow rate of fluid through a vessel (quantity per unit time)
ΔP = pressure gradient, or P1 − P2
P1 = pressure at the inflow end of a vessel
P2 = pressure at the outflow end of a vessel
R = resistance of blood vessels
Factors affecting flow rate
- Pressure gradient — driving force for flow
- Resistance— hindrance to flow caused by friction between fluid and walls
How to calculate for resistance in blood vessels
o Viscosity, η, increases with hematocrit
o Vessel length, L
o Vessel radius, r
R = 8ηL/πr^4
These are the major resistance vessels
Arterioles
Total resistance offered by all the systemic peripheral vessels
Total Peripheral resistance
The primary determinant of total
peripheral resistance is the
adjustable arteriolar radius
States that flow of blood is directly proportional to pressure gradient, inversely related to viscosity
Poiseuille-Hagen Law
Q = πΔPr^4/8ηL
Relative viscosity of blood decreases with diameter and approaches the viscosity of plasma (< 0.3 mm diameter vessels)
Fahraeus-Lindqvist effect
accumulation of RBC in the center of blood stream, leaving the sides of vessels low in RBC and high in plasma
Plasma Skimming Effect
Found in the medulla, can regulate cardiac output and arteriolar resistance to maintain proper blood flow for gas transprot
Cardiovascular Control Center
(pressure sensors, a type of mechanoreceptor) - monitor blood pressure at various sites in the cardiovascular system
Baroreceptors
Baroreceptor that protects blood flow to the brain
Carotid Sinus Baroreceptor
Baroreceptor that protects blood flow to the heart
Aortic Arch Baroreceptor
- Respond with an increase in discharge frequency to an in- crease in CO, or to decreases in 02, and pH of the blood perfusing the carotid and aortic bodies
Arterial Chemoreceptors
Check DIagrams on the last 5 pages of the pdf
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