Lecture #1 Flashcards by Bryan Edwards

The Pulmonary Circuit has _____ pressure and _____ resistance. The Systemic Circuit has ______ pressure and _____ resistance.

Low, Low

High, High

How well did you know this?

Not at all

Perfectly

Role of cardiovascular system? (7)

Gaseous Exchange
Waste Removal
Delivery of Nutrients
Delivery of Hormones
Defense
Thermal Exchange
Tissue Hydration

How well did you know this?

Not at all

Perfectly

What is cardiac output? Three variables it depends on?

Volume of Blood Pumped Per Minute

HR, Force of Contraction, and SV

How well did you know this?

Not at all

Perfectly

What does non-sucking pump mean

Outflow is intermittent and inflow is continuous

How well did you know this?

Not at all

Perfectly

Systemic Vascular Resistance =

Total Peripheral Resistance

How well did you know this?

Not at all

Perfectly

Four important variables in CV function?? Part of CV that controls them?

Heart/CO
Arterioles/Resistance
Veins, Venules/Capacity
Veins, Venules/Blood Volume

How well did you know this?

Not at all

Perfectly

BV layers from outside to inside.

Adventitia (Connective Tissue)
Media (Smooth Muscle)
Intima (Vascular Endothelium)

How well did you know this?

Not at all

Perfectly

Which BV layers are absent in capillaries?

Caps lack media and adventitia.

How well did you know this?

Not at all

Perfectly

Three things synthesized by Intima?

Prostacyclin – Vasodilator, inhibitor of platelet aggregation
NO – same + inhibits leukocyte adhesion
Endothelin – Vasoconstrictor

How well did you know this?

Not at all

Perfectly

Cells the usually surround capillaries?

Pericytes

How well did you know this?

Not at all

Perfectly

What do pericytes do anyway?

Regulate tight and adherens junctions
Regulate vascular stability and angio
Contractile
Phagocytic

How well did you know this?

Not at all

Perfectly

Two vessel types that lack media.

Capillaries

Non-muscular Venules

How well did you know this?

Not at all

Perfectly

What could cause media contraction?

Sympathetic stim of alpha 1 adrenergic

Vasoconstrictors (VP, ATII, Endothelin, adrenaline)

How well did you know this?

Not at all

Perfectly

Loss of vessel tone will cause what changes to capacitance and resistance?

Vasodilation
More Capacitance
Lower Systemic Resistance

How well did you know this?

Not at all

Perfectly

Main controllers of vasodilation?

Metabolically generated substances (H+, CO2, Adenosine)

Vasodilators (Prostacyclin, NO)

How well did you know this?

Not at all

Perfectly

Who hangs out in the adventitia?

Fibroblasts
Immune Cells
Stem Cells
Adrenergic Nerve Endings

How well did you know this?

Not at all

Perfectly

What are vasa vasorum?

Small BV for big BV (like aorta)

How well did you know this?

Not at all

Perfectly

Three major by-passes of the fetal circulation.

Ductus Venosus
Foramen Ovale
Ductus Arteriosis

How well did you know this?

Not at all

Perfectly

How is fetal liver blood flow controlled?

Fetal ductus venosus contraction

Describe the route of blood through a fetus

Placenta, Ductus Venosus, Inf. VC, RA, Foramen Ovale, LA, LV, Aorta, Umbilical arteries to placenta for oxygenation, or lower half of body

What happens to blood that doesn’t make it through foramen Ovale?

Mixes with SVC blood, into RV, Pulmonary Trunk, Ductus Arteriosis, Aorta

Relationship of Pressure, Flow, and Resistance

Pressure Change = Flow X Resistance

Most important variable in resistance?

radius of the tube

What does the fourth power law establish?

Resistance is proportional to 1/r^4

At birth, resistance of the ______ circuit increases and resistance of the _______ circuit decreases.

Increase in Systemic | Reduction in Pulmonary

What causes rise in systemic resistance?

Loss of Placenta

How does the increase in systemic resistance cause changes in blood flow?

Increased systemic pressure increases LA pressure | Pressure Increase Closes Foramen Ovale

What two factors cause the pulmonary resistance to fall?

Relieved Hypoxic Pulmonary Vasoconstriction | Mechanical Factors

Name the four structural changes that occur at or after birth.

Closure of ductus venosus Closure of foramen ovale closure of ductus Arteriosus Increase in LV Mass, Decrease in RV

What is a relic of the ductus venosus?

Ligamentum Venosum

Describe ductus venosus closure.

Within a few hours of loss of umbilical blood flow, the muscular wall of ductus will contract, closing the lumen

How does the foramen ovale close?

Higher RA pressure pushes the valve against the septum secundum. It eventually adheres.

What is the relic of foramen ovale?

Fossa Ovalis

If fusion if the foramen ovale doesn't entirely happen - is this a problem?

Probably not -- pressure will likely hold it closed anyway.

How does ductus arteriosus close?

Pressure changes reverse blood flow in the duct. Exposure to oxygen causes the media to constrict, eventually closing and filling with fibrous tissue. Also...bradykinin helps with vasoconstriction.

Relic of the ductus arteriosus?

Ligamentum Arteriosum.

Three common types of congenital heart defects...

Stenosis L --> R Shunts R --> L Shunts

Difference between post-ductal and pre-ductal coarction of aorta.

Post ductal -- Common -- Ductus closes, patients survive normally, but rarely live past 40 Pre ductal -- No ductal flow reversal at birth, fetal blood flow pattern persists.

Three causes of L --> R Shunts

Patent Ductus Arteriosus Ventricular Septal Defects Atrial Septal Defects

Patent ductus arteriosus associated with...

Maternal Rubella | Premature Birth

Most common atrial septal defect?

Patent Foramen Ovale

Two sources/signs of R-->L Shunt

Preductal Coarctation of the aorta (patent ductus) | Tetralogy of Fallot

Four Defects associated with Tetralogy of Fallot

Dextroposed Aorta (can override septum) Pulmonary Valve/Trunk Stenosis Ventricular Septal Defect Right Ventricular Hypertrophy

So...explain why exactly Tetrology of Fallot leads to blue babies.

In this condition, the blood is being pushed through the defect between the ventricles, allowing almost all of the blood that enters the heart to leave without being oxygenated.

Treatment for Fallot?

Widen the pulmonary Stenosis Close the Septal Defect Reconstruct the Flow pathway