Lecture 29 - Vascular System Flashcards
what are the Functions of the Vascular System
The vascular system, also known as the circulatory system, is responsible for transporting blood, nutrients, oxygen, and waste products throughout the body
Overall, the vascular system is essential for the proper functioning of the body and helps maintain homeostasis, or balance, within the body.
do all tissues receive equal blood volumes
no
what are the two types of circulation in the Vascular System
Pulmonary circulation: This type of circulation carries deoxygenated blood from the heart to the lungs, where it picks up oxygen and releases carbon dioxide. The oxygenated blood then returns to the heart, where it is pumped out to the rest of the body.
Systemic circulation: This type of circulation carries oxygenated blood from the heart to the rest of the body’s tissues and organs, where it provides oxygen and nutrients and removes waste products. Deoxygenated blood then returns to the heart, where it is sent to the lungs for oxygenation through pulmonary circulation.
Pulmonary(to the lung) vs. Systemic(to all other tissues)
what is the difference between Arterial and Venous
Arterial (oxygenated) vs. Venous (deoxygenated)
what is the difference between Macro and Micro-circulation
Macro (big vessels - arteries and veins)
vs.
micro-circulation (small vessels - arterioles, venules, capillaries)
Macro: Takes blood to or
from organs
Micro: distributes blood
within each organ
Types of blood vessels
Arteries(macro)
Arterioles(micro)
Capillaries(micro)
Veins(macro)
what is a distinguishing feature of Arteries
thick elastic walls to withstand high pressure
what is a distinguishing feature of Arterioles
muscular walls that control blood flow; considered the ‘control valves’ for capillary beds
what is a distinguishing feature of Capillaries
join arterioles to venules
only made of endothelial cells
thin walls allow for exchange of gases, nutrients, and fluid
what is a distinguishing feature of Veins
thin walls, low pressure system, high volume; “blood reservoir”
what is the formula for flow
change in pressure/ resistance
what is the formula for cardiac output
MAP/ TPR
Absolute pressure does NOT determine blood flow. True or false.
true
The pressure GRADIENT along the length of the tube determines blood flow
what is Oscillatory flow
periods of higher flow followed by periods of lower flow, however there will always be constant flow because of the Windkessel Effect
why does oscillatory flow decrease at the level of the capillaries
When flow hits capillaries, they don’t have elastin or smooth muscle to contract, so the oscillatory flow decreases; this occurs in the venules and veins as well where flow is steady
where is the Largest pressure drop
at the level of arterioles to prevent damage to capillaries
List 3 reasons why MAP is important
1 homeostatically regulated variable in your body
Provides ‘driving force’ to move blood through the circulation
Contributes to the heart’s ‘workload’
List the following in regards to low BP:
Systolic BP/Diastolic BP =
Symptoms:
Causes:
Risk factors:
also known as:
Systolic BP/Diastolic BP = 90/60 mmhg
Symptoms: dizziness, fainting, fading vision, fatigue, nausea, trouble concentrating
Causes: dehydration, pregnancy, heart failure, endocrine disorders, blood loss, anemia
Risk factors: age, certain medications, certain diseases (Parkinson’s, diabetes, heart disease)
also known as: hypotension
List the following in regards to high BP:
Systolic BP/Diastolic BP =
Symptoms:
Causes:
Risk factors:
also known as:
Stage 1: SBP/DBP = 130-139/80-89, Stage 2: ≥140/≥90, Hypertensive crisis: >180/>120
Severe symptoms: blindness, chest pain, pregnancy complications, heart attack, heart failure, dementia, stroke, pulmonary edema, sudden loss of kidney, sexual dysfunction
Causes: atherosclerosis, congenital heart defects, kidney disease, obstructive sleep apnea, thyroid problems
Risk factors: age, ethnicity, genetics, obesity, physical inactivity, tobacco use/vaping, high sodium intake, low potassium levels, excessive alcohol consumption, stress, pregnancy
what are arteries
Function
arteries are Conduit Vessels
Function: conduit arteries must take blood(oxygenated) from the heart and distribute it to the various organs/tissues as efficiently as possible
what factors contribute to the arteries being able to efficiently completing their function
1.Minimize resistance to flow:
* Large diameter
* Low contractility [smooth muscle – active process]
* High distensibility (compliance) [elasticity – passive process]
2.Artery walls must be “strong” to withstand high systolic blood pressures
what happens during systole in regards to the aorta
Elastic-walled aorta is compliant;
- Distends PASSIVELY during systole
what happens during Diastole in regards to the aorta
Elastic-walled aorta is compliant;
- Recoil PASSIVELY during diastole
Major benefits of compliance in the aorta
- Lowers systolic blood pressure (i.e., by distending)
- Converts intermittent flow into continuous flow (aka Windkessel Effect)
what is the Windkessel Effect
helps dampen the fluctuations in blood pressure (pulse pressure) over a cardiac cycle and to maintain continuous blood flow when ventricular ejection ends( i.e. diastole)
What allows for aortic compliance?
Elastin = a matrix protein that increases compliance
Elastin polymers are very flexible
what is Pulse Pressure
Difference between systolic pressure and diastolic pressure
120-80 = 40
Pulse Pressure is usually the pressure at your _____________
brachial artery
what does the Dicrotic notch represent
when the aortic valve closes, there is a point when the heart contracts against the valve → slightly increases pressure in ventricle
What Modifies Pulse Pressure?
Stroke volume (large SV increases pressure in aorta/systolic pressure)
Speed of blood ejection into the aorta (contractility of the heart)
Aortic compliance: high compliance = low systolic blood pressure, vice versa (inverse)
What Happens with Aging in regards to Pulse Pressure
Aging decreases aortic compliance/increases stiffness
With aging, pulse pressure increases
Hypertension: 140 systolic/90 diastolic
Systolic BP increases as weight lifted increases. Why?
oxygen demand and metabolic rate increase –> increased cardiac output and blood pressure to deliver oxygen and nutrients to the working muscles.
As a result, systolic blood pressure (the pressure in the arteries when the heart contracts) can increase during weightlifting or other types of exercise.
In addition, weightlifting can also increase sympathetic nervous system activity, which can further increase blood pressure. The sympathetic nervous system is responsible for the “fight or flight” response and can cause vasoconstriction (narrowing of blood vessels) and increased heart rate and contractility, which can increase blood pressure.
