CV: Fine-Tuning Flashcards
How does early systole affect blood flow through the coronary artery and why
Reduces blood flow through the coronary artery as the myocardial cells contract and compress it
At What stage of the cardiac cycle does blood enter the coronary arteries
Diastole
How does a decreased pO2 effect blood moving through coronary arteries
It will cause vasodilation in the coronary arteries
How does a disease causing decreased metabolic rate affect the blood flow through the coronary arteries
Reduces blood flow
How will work done by the cardiac myocytes affect blood flow through the coronary arteries
Increased work done will increase blood flow through the coronary arteries
How does local metabolic activity of cells in the heart affect blood flow via the coronary arteries
It increases the flow through them as increased metabolic activity of the myocytes means they need more oxygen
How does local metabolic activity of cells in the skin affect blood flow to the skin
No effect as blood flow to the skin is controlled by thermoregulation not by metabolic activity of the cells
How does local metabolic activity of the cells at the lungs affect blood flow to the lungs
The entire CO of the RV HAS to move through the lungs regardless of local cell metabolic activity (usually blood moving through the lungs exceeds the metabolic capacity of the cells in the lungs)
Which wall is thicker the right and left atria
They are both the same size as they have similar workloads
Three factors affecting the pressure in the arteries
Length
Blood Viscosity
Radius of the capillaries
How does halving the radius affect the pressure
It causes the resistance to increase 90%
During isovolumic ventricular contraction, what happens to the pressure in the atria?
The pressure in the atria increases as the mitral and tricuspid valves bulge up into the atria
How does a decrease in serum calcium ions affect the force of contraction in the left ventricle
It will decrease as the CONTRACTILITY of the myocytes will decrease
How does an increase in serum potassium ions affect the force of contraction in the left ventricle
It will decrease as CONTRACTILITY of the myocytes will decrease
If my HR decreased, how would CO be affected
Depends. Could decrease but SV might increase to cancel out the effect:
CO = SV x HR
What has a smaller total SA, arterioles or capillaries
arterioles
Are purkyne tissues smaller or larger than ventricular myocardial cells and why
They are larger because electrical conduction needs to be rapid in order to reach the cells
Why do arterioles offer a much greater resistance to flow than other vessels
Due to a greater pressure drop along their length
Does the thick muscular wall of the arterioles affect resistance
No
Does a small internal diameter affect arteriolar resistance
No, the aorta has a smaller internal diameter but less resistance
How does RV CO affect stroke volume in the LV?
It causes more blood to enter the LV via the pulmonary vein which causes greater pre-load. So SV increases in the LV
What does the vasa vasorum supply
Elastic Arteries and Large Veins
Where are elastic arteries and muscular arteries found
Elastic is proximal to the heart and these become muscular distally
Elastic vs Muscular arteries
Elastic contain collagen and elastin in the tunica media whilst the muscular arteries contain smooth muscle
Why do we need elastic arteries
Helps to maintain a constant pressure despite the pulsing nature of blood flow
Why do we need muscular arteries
Acts as resistance to flow
How can I palpate the apex of the heart
Left 5th intercostal space and left mid-clavicular line
At what vertebral level does the heart start at
T4/5
What are the intercostal muscles innervated by
T1-T11
What is the anterior abdominal wall innervated by
T7 -T11
T12
What is the thoracic cavity supplied by
Internal thoracic artery
What does the internal thoracic artery bifurcate into
Superior epigastric artery and musculophrenic artery
At what vertebral level does the internal thoracic artery bifurcate
6th intercostal space
What does the posterior intercostal artery branch off from
Aorta
What do the anterior intercostal artery branch off from
Internal thoracic artery or Musculophrenic branch
What are venae comitantes
Paired veins accompanying major arteries
Why are venae comitantes located so close to arteries
Artery pulsations assist flow of blood through the veins
What are four roles of the pericardium
a) Fixes the heart to limit motion
b) Prevents overfilling of the heart
c) Lubrication to reduce friction generated by the heart
d) Protection from infection
What nerve innervates the pericardium
Phrenic nerve
What is the cephalic vein a branch of
Subclavian vein
How does factor VII circulate in the blood
Bound to vWF
What would be the consequence of vWF not being bound to factor VIII
it would degrade RAPIDLY
What compound causes the release of factor VIII from vWF
Thrombin
Where is additional vWF released and why is this needed
Released from the endothelium + needed to form additional links between glycoproteins 1b/X/V and collagen fibrils
How does thromboxane A2 cause platelet aggregation
By increasing expression of glycoprotein receptors IIb/IIIa on platelet plasma membrane
What also causes an increases of receptor IIb/IIIa expression
ADP
What effect does thromboxane A2 have on blood vessels
Vasoconstriction
