lecture 8 Flashcards
Arterial blood flows in which direction?
Arterial blood flows away from the heart
Venous blood flows in which direction?
Venous blood flows toward the heart
Which contracts first atria ventricles?
Atria
Tricuspid and mitral valves control flow between?
the atria and ventricles
Aortic and pulmonary control flow from?
the ventricles out to the circulatory vessels
How many myocytes are activated during each heart beat?
Every myocyte is activated
How can you increase force of a cardiac contraction?
Increase cystolic Ca2+ level
increase number of cross-bridges formed
increase force of contraction
Cellular mechanism of cardiac relaxation?
Decrease in cystolic Ca2+ levels, pumped back into sarcoplasmic reticulum
ATP binds to myosin to release cross bridges
All cardiomyocytes relax
What is the name of the circuit that sends oxygen-rich blood back to the tissues of the body and brings oxygen-poor blood back to the heart?
Systemic circuit
Which circuit has the least resistance?
pulmonary circuit
Q=P/R
flow = pressure difference / resistance
Which circuit has a higher arterial pressure?
Systemic
High blood pressure is called?
Hypertension
Low blood pressure is called?
Hypotension
Diastole is when?
Heart muscle relaxes and the chambers of the heart fill with blood, blood pressure decreases.
the mitral and tricuspid valves are open
Systole is when?
Period of contraction of the ventricles of the heart and blood is ejected into the aorta and pulmonary trunk
CO2 is removed at the?
Pulmonary capillaries
Deoxygenated blood from the systemic circulation drains from?
The superior and inferior vena cava into the right atrium -> right ventricle -> pulmonary trunk -> pulmonary arteries -> lungs
Oxygenated blood travels from?
The lungs in the pulmonary veins -> left atrium -> left ventricle -> aorta -> periphery
How are cardiomyocytes connected physically?
Intercalated discs
Which junctions help for better spread of calcium?
Gap junctions directly connect cells cytoplasm which allows currents to move between adjacent cells
The direct connection between cardiac cells allow?
The heart to pump as a functional synctium
what are the key phases of the cardiac cycle?
Atrial systole isovolumetric contricular contraction ventricular ejection Isovolumetricular ejection Ventricular diastole
During which phase of the cardiac cycle is the largest spike in pressure?
Isovolumetric contraction
What does isovolumetric mean?
The valves are closed so there is no gain or loss of blood but the heart is contracting or relaxing
What is pulse pressure?
The difference between systolic and diastolic pressure
What are systolic and diastolic pressure?
systolic is the highest point of the systole phase and diastolic is the lowest point of diastole phase
Which valves are open and/or closed during atrial systole?
Av valves are open and the ventricle and atria are filling but the semilunar valves are closed
Which valves are open or closed during isovolumetric contraction?
Av valves and semilunar valves are closed and the ventricles are contracting
Which valves are open or closed during ventricular ejection?
Semilunar valves are open, Av valves are closed
Which valves are open or closed during isovolumetric contricular relaxation?
Semilunar and AV valves are shut
Which valves are open or closed during passive filling?
AV valves are open but semilunar valves are closed.
What causes the aortic valves to open?
When the ventricular pressure exceeds the aortic pressure
Which phase of the cardiac cycle has the biggest pressure spike?
Isovolumetric contraction
Name the 5 phases of the cardiac cycle?
Atrial systole Isovolumetric contraction Ventricular ejection isovolumetric contricular relaxation ventricular diastole
