Lecture 2 (Revised) Flashcards
Blood Vessel Wall comprises 3 main layers?
-Tunica intima
-Tunica media
-Tunica adventitia
Large Arteries contain?
A thick media layer and higher amount of elastin
Amount of elastin in small arteries?
Decreases, because they have more smooth muscle
Veins contain ___ elastin tissue?
Less
Pulse Blood Pressure?
Systole - Diastole
How to measure Blood Pressure?
-Constrict laminar flow so it becomes turbulent and makes a sound
-Must be greater than Diastolic and less than Systolic
Resistance is determined by?
Blood viscosity, vessel length, and vessel radius
A vessel having twice the length of another vessel will have?
Twice the resistance to flow
If viscosity of blood increase 2-fold, the resistance to flow will?
Increase 2-fold
An increase in radius?
Reduces resistance
Arteries to Arterioles have?
Increased cross-sectional area (dramatically decreasing resistance and blood pressure)
Vascular Tone?
(how much constriction is it going through)
-Degree of Constriction
-Determined by balance of vasoconstriction and vasodilation
Extrinsic Factors of Vascular Tone?
Neural or Hormonal (Affecting Blood Flow)
Intrinsic Factors of Vascular Tone?
Increased oxygen demand/myogenic response (Different factors within tissues or vessels)
Stenosis?
(Usually occurs in large arteries)
-Abnormal narrowing of an artery, partially obstructs blood flow
-Increases vascular resistance
Stenosis increases?
Vascular Resistance
Vessel Compliance?
Ability of a vessel to distend and increase volume (expand and contract passively)
Compliance of Arteries is?
Much lower than veins due to containing higher elastin and vascular smooth muscle cells
Elastin tissue enables a blood vessel to?
Expand and contract passively with changes in pressure
Elastic Arteries act as a?
Pressure Reservoir, allowing continuous blood flow, reduce workload, and reduce blood pressure fluctuation
Arterial Compliance as we age?
Decreases, because arteries start to stiffen (more collagen, less elastin)
Decreasing compliance means?
-Increase Systolic Blood Pressure (due to stiffening)
-Diastolic will remain the same
-Pulse Pressure will increase
Physiological Properties of Veins?
-High compliance
-Low resistance (decreased pressure to get blood back to Heart)
-Blood Reservoir System
-Venous valves provide one-way flow towards right heart
Biggest Determinants of Venous Return to Heart?
Pressure Gradient and Skeletal Muscle Pump with Venous Valves
Stroke Volume (SV)?
Volume of blood pumped out from LV per beat
Cardiac Output (CO)?
Volume of blood being pumped out by the Heart, by LV or RV per unit time, equals to SV x HR
(Effects of Stroke Volume on Arterial BP) Increasing SV will?
-Increases flow
-Increases systolic BP
-Increases PP
-Eventually Increasing diastolic BP
(Effects of Stroke Volume on Arterial BP) Decreasing SV will?
-Decreases flow
-Decreases systolic BP
-Decreases PP
-Eventually Decreasing diastolic BP
(Effects of Heart Rate on Arterial BP) Increasing HR will?
-Increase systolic BP
-Increase diastolic BP
-Mean pressure will increase because diastolic increases
(No Change in PP)
(Effects of Heart Rate on Arterial BP) Decreasing HR will?
-Decrease systolic BP
-Decrease diastolic BP
(No Change in PP)
(Effects of Peripheral Resistance on Arterial BP) Increasing Total Peripheral Resistance?
-Increase systolic BP
-Increase diastolic BP
(No Change in PP)
(Effects of Peripheral Resistance on Arterial BP) Decreasing Total Peripheral Resistance?
-Decrease systolic BP
-Decrease diastolic BP
(No Change in PP)
Aorta and Large Arteries have lowest cross-sectional area?
(Lowest radius, Highest resistance)
-Highest BP
Arterial Compliance?
Ability to expand and compress
Windkessel Effect?
(Works as a pump due to compliance with elasticity)
-Aorta and large arteries distend when BP rises during systole
-Aorta and large arteries recoil when BP falls during diastole
Blood Reservoir helps when?
Working out because we need blood for our muscles
1) Pressure Gradient?
Going from a high pressure area to a low pressure area (divides the blood back to the Heart)
2) Skeletal Muscle Pump?
-When relaxed blood goes through
-When contracted (blood at top goes to the Heart and prevents blood from coming back)
When Skeletal Muscle closes due to contraction it prevents?
Backflow
5 Ways of Venous Return to Heart?
1) Pressure Gradient
2) Skeletal Muscle pump with venous valves
3) Respiratory Pump
4) Regulated Sympathetic Vasoconstriction
5) Cardiac Suction Effect
3) Respiratory Pump Inhalation?
-Increase blood flow into thoracic cavity to Heart
-Blood filling occurs
-Decrease pressure in thoracic area
-(Diaphragm contracts) Increase pressure in abdominal area
3) Respiratory Pump Exhalation?
(Helps with Heavy Exercises)
-Decrease blood flow into thoracic cavity to Heart
-Increase pressure in thoracic area
-(Diaphragm relaxes)
Decrease pressure in abdominal area
4) Regulated Sympathetic Vasoconstriction?
(fight or flight)
-Increase sympathetic (vasoconstriction)
-Increase venous pressure
-Increase venous return
-Increase EDV (blood to be pumped out)
5) Cardiac Suction Effect?
