Cardiovascular/Blood Flashcards
Pulmonary Circulation
Heart-Lungs-Heart
Systemic Circulation
Heart-Body-Heart
Arteries
Carry oxygenated blood away from the heart and to the body
Veins
Carry oxygen poor blood back from the body to the heart
Benefits of the parallel arrangement
- systemic organs can receive arterial blood of identical composition
- systemic organs can receive similar pressure gradient
- blood flow to the systemic organs can be independently controlled
- reduced total peripheral resistance
Contractile cells
- Na+ channels open causing initial depolarization
- At the peak of depolarization Na+ channels close and Fast-K+ channels open
- At the plateau Ca** channels open and Fast-K+ channels close
- At repolarization there is an increased permeability to K+ and slow-K+ channels open
Autorhythmic Cells
- If channels are permisible to both Na+ and K+. Open when Na+ influx > K+ efflux. Depolarization if channels close
- t-Ca++ open as potential becomes more positive and bring the cell to threshold. At threshold they close and L-Ca++ channels open
- K+ channels open at the peak of depolarization and K+ efflux causes repolarization
Late Diastole
Both sets of chambers are relaxed and ventricles fill passively
Atrial systole
Atrial contraction forces a small amount of additional blood into the ventricles
Isovolumic ventricular contraction
First phase of ventricle contraction pushes av valves closed by does not create enough pressure to open semilunar valves
Ventricular ejection
As ventricular pressure rises and exceeds pressure in the arteries the semilunar valves open and blood is ejected
Isovolumic ventricular relaxation
As ventricles relax pressure in ventricles falls and blood flows back into cusps of semilunar valves and snaps them closed
P wave
Depolarization of atrial muscle
P-R or P-Q interval
SA node depolarizations to start of ventricular depolarization. Conduction through av node and av bundle. Atrial contracts
QRS complex
Depolarization of ventricular muscle
S-T segment
Depolarized state of ventricular muscle. Ventricles contract
T wave
Repolarization of ventricular muscle
Q-T interval
Total time for ventricular depolarization and repolarization
T-P interval
Refractory period, heart is at rest
MAP
Determined by blood volume, effectiveness of the heart as a pump, resistance of the system to blood flow, and relative distribution of blood between arterial and venous blood vessels
Colloid osmotic pressure
Determined by the solute concentration within a compartment. Exerted by interstitial fluid onto capillary
Hydrostatics pressure
Pressure of the fluid upon the surface of a compartment
Hemostasis- temporary blockage
Done by a platelet plug. Platelets stick to exposed collagen. Platelets secrete cytokines to reinforce vasoconstriction and activate more platelets
Norepinephrine
Attached to alpha 1 receptors with a high affinity for norepinephrine causing vasoconstriction
Epinephrine
Travels through the blood with not as high affinity for alpha receptors however it does still bind and reinforce vasoconstriction. Beta 2 receptors in the liver, heart and skeletal muscles cause vasodilation.
Increased venous return
Causes an increased stretch and an increased contractile force to accommodate for the increased venous return
