Quiz Arterial and Venous Systems Flashcards
What tissues make up the wall of an artery?
endothelium, elastic tissue, smooth muscle, fibrous tissue
What are the 3 different tissue layers in the wall of an artery?
intima, media, adventitia
What tissues make up the wall of an arteriole?
endothelium, smooth muscle
What tissues make up the wall of a vein?
endothelium, elastic tissue, smooth muscle, fibrous tissue
What is the primary function of the arterial system?
distribution of blood to the capillary systems in the body
What part of the vascular system regulates the flow of blood to the various capillary beds?
Arterioles
Where is the lowest pressure in the vascular system as blood travels from the aorta back to the right atrium?
Right Atrium
What is pulse pressure?
PP= Systolic BP - Diastolic BP
What formula can be used to estimate mean arterial pressure?
MAP = P diastolic + 1/3 (P systolic - P diastolic)
What are some of the changes in the arterial waveform as blood travels distally to the extremities?
look at slides
In a healthy individual, would you expect a higher or lower systolic blood pressure reading in the foot as compared to the aorta?
Higher
How does the arterial system convert pulsatile bloodflow to continuous bloodflow at the level of the capillaries? What is the advantage of continuous blood flow at the capillary level?
Hydraulic filtering converts the intermittent output of the heart to a steady flow in the capillaries
Does the heart have to work harder to pump blood through rigid vessels?
Yes
What are some of the factors that affect pulse pressure?
Stroke Volume, Compliance
Why do our arteries become stiffer as we get older?
become less compliant due to loss of elastic tissue
What are the primary functions of the veins?
-Reservoir for the cardiovascular system
70% of the blood volume may be stored in the veins
-Venous pump helps propel blood forward
Enhances venous return
What factors regulate CVP?
- A balance of the heart to pump blood out of the right atrium and right ventricle into the lungs
- The tendency for blood to flow from the peripheral veins to the right atrium (venous return)
What factors increase CVP?
-Decreased Cardiac Output
-Increase in Total Blood Volume
-Venous Constriction
-Gravity
Standing to supine position
-Arterial Dilation
-Respiratory Activity
Increased rate and rate of respiration
-Skeletal Muscle Pump
Exercise
When a person is standing where would you find the highest venous pressures in the body? Where would you find the lowest venous pressures in the body?
Feet
Sagittal Sinus (Head)
What is a major risk of performing neurosurgery in the sitting position?
Air Embolism
How does respiration affect venous return?
-Spontaneous respiration
Decreased intra-thoracic pressure results in a decreased right atrial pressure which enhances venous return
-Mechanical ventilation
Increased intra-thoracic pressure during positive-pressure lung inflation causes increased right atrial pressure which decreases venous return
-Valsalva Maneuver
Causes a large increase in intra-thoracic pressure which impedes venous return to the right atrium
How much of the total blood volume is normally found in the venous system?
70%
Where are some of the major venous blood reservoirs in the body?
Specific Reservoirs
- Spleen
- Liver
- Large abdominal veins
- Venous plexus beneath the skin
Why are the arterioles called the “stopcocks” of the circulation?
Regulate flow into the capillaries
What are some of the characteristics of the capillaries that make them ideal for nutrient and fluid exchange with the surrounding tissues?
greatest cross sectional area, greatest surface area
Do the walls of capillaries contain smooth muscle?
NO
Why can capillaries withstand high intravascular pressures?
LaPlace’s Law, tiny radius, low wall tension
What are some of the mechanisms of exchange across the capillary endothelium?
Diffusion, Bulk Flow, Vesicular Transport
Is the permeability of the capillary endothelium the same in all the tissues of the body?
NO
What are the 2 major body fluid compartments?
Intracellular Fluid (40%) Extracellular Fluid (20%)
Approximately what percentage of body weight is made up of total body water?
60% ICF+ECF
What percentage makes up each of the 2 major body fluid compartments?
ICF (40%)
ECF (20%)
If you gave a person 1 liter of intravenous normal saline (0.9% NaCl) how would it distribute over the various fluid compartments?
see slides
If you gave a person 1 liter of intravenous 0.5% dextrose how would it distribute over the various fluid compartments?
see slides
