Lecture 29 - Vascular System

Question 1

what are the Functions of the Vascular System

Answer 1

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.

Question 2

do all tissues receive equal blood volumes

Answer 2

no

Question 3

what are the two types of circulation in the Vascular System

Answer 3

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)

Question 4

what is the difference between Arterial and Venous

Answer 4

Arterial (oxygenated) vs. Venous (deoxygenated)

Question 5

what is the difference between Macro and Micro-circulation

Answer 5

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

Question 6

Types of blood vessels

Answer 6

Arteries(macro)
Arterioles(micro)
Capillaries(micro)
Veins(macro)

Question 7

what is a distinguishing feature of Arteries

Answer 7

thick elastic walls to withstand high pressure

Question 8

what is a distinguishing feature of Arterioles

Answer 8

muscular walls that control blood flow; considered the ‘control valves’ for capillary beds

Question 9

what is a distinguishing feature of Capillaries

Answer 9

join arterioles to venules
only made of endothelial cells
thin walls allow for exchange of gases, nutrients, and fluid

Question 10

what is a distinguishing feature of Veins

Answer 10

thin walls, low pressure system, high volume; “blood reservoir”

Question 11

what is the formula for flow

Answer 11

change in pressure/ resistance

Question 12

what is the formula for cardiac output

Answer 12

MAP/ TPR

Question 13

Absolute pressure does NOT determine blood flow. True or false.

Answer 13

true
The pressure GRADIENT along the length of the tube determines blood flow

Question 14

what is Oscillatory flow

Answer 14

periods of higher flow followed by periods of lower flow, however there will always be constant flow because of the Windkessel Effect

Question 15

why does oscillatory flow decrease at the level of the capillaries

Answer 15

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

Question 16

where is the Largest pressure drop

Answer 16

at the level of arterioles to prevent damage to capillaries

Question 17

List 3 reasons why MAP is important

Answer 17

1 homeostatically regulated variable in your body

Provides ‘driving force’ to move blood through the circulation 

Contributes to the heart’s ‘workload’

Question 18

List the following in regards to low BP:

Systolic BP/Diastolic BP =

Symptoms:

Causes:

Risk factors:

also known as:

Answer 18

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

Question 19

List the following in regards to high BP:

Systolic BP/Diastolic BP =

Symptoms:

Causes:

Risk factors:

also known as:

Answer 19

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

Question 20

what are arteries

Function

Answer 20

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

Question 21

what factors contribute to the arteries being able to efficiently completing their function

Answer 21

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

Question 22

what happens during systole in regards to the aorta

Answer 22

Elastic-walled aorta is compliant;
- Distends PASSIVELY during systole

Question 23

what happens during Diastole in regards to the aorta

Answer 23

Elastic-walled aorta is compliant;
- Recoil PASSIVELY during diastole

Question 24

Major benefits of compliance in the aorta

Answer 24

1. Lowers systolic blood pressure (i.e., by distending)
2. Converts intermittent flow into continuous flow (aka Windkessel Effect)

Question 25

what is the Windkessel Effect

Answer 25

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)

Question 26

What allows for aortic compliance?

Answer 26

Elastin = a matrix protein that increases compliance

Elastin polymers are very flexible

Question 27

what is Pulse Pressure

Answer 27

Difference between systolic pressure and diastolic pressure

120-80 = 40

Question 28

Pulse Pressure is usually the pressure at your _____________

Answer 28

brachial artery

Question 29

what does the Dicrotic notch represent

Answer 29

when the aortic valve closes, there is a point when the heart contracts against the valve → slightly increases pressure in ventricle

Question 30

What Modifies Pulse Pressure?

Answer 30

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)

Question 31

What Happens with Aging in regards to Pulse Pressure

Answer 31

Aging decreases aortic compliance/increases stiffness

With aging, pulse pressure increases

Hypertension: 140 systolic/90 diastolic

Question 32

Systolic BP increases as weight lifted increases. Why?

Answer 32

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.