Chapter 15 Flashcards
What layer of the blood vessel wall is responsible for vasoconstriction/dilation?
The tunica media
What layer of the blood vessel wall is responsible for preventing or allowing blood clotting?
Tunica Intima
What layer of the blood vessel wall is responsible for resistance to high blood pressure by providing structure?
Tunica Media
What layer of the blood vessel wall is responsible for formation of new blood vessels?
Tunica Intima
Which is more elastic, veins or arteries? WHY???
Arteries are because they need to withstand the high pressure of blood pumped directly from the heart. THEY ARE ALWAYS UNDER CONSTANT PRESSURE.
Veins are less elastic so they can hold a very high percentage of the blood in circulation
Explain elastic rebound in the large arteries
When the ventricle pushes the blood out the artery walls stretch because of the pressure (cushions the pressure during ventricular systole). Then when the ventricle relaxes (ventricular diastole) and there is no more pressure. Then it causes the artery walls to snap back (un stretch) and it sends a huge force in the artery to get the blood to the rest of the body.
How does elastic rebound affect systolic blood pressure?
It lowers systolic blood pressure
How does elastic rebound affect diastolic blood pressure?
It raises diastolic pressure
What type of vessel carries the highest percentage of blood at rest?
Veins and venules
What are the 2 things allow venous blood to return to the heart REAGARDLESS of low blood pressure?
- The skeletal muscle pump
- Respiratory pump
What causes varicose veins? (4) And what is it?
Sitting and standing in one place for long periods of time, pregnancy, obesity pressures or it is heredity
It is where blood pools in the leg veins stretching the walls and the valves no longer work
What are continuous capillaries and their functions?
They are endothelium complete lining capillaries connected by tight junctions
Functions: Prevent blood loss, keep plasma in the blood, allows passage of water, solutes, and lipid-soluble materials
What are fenestrated capillaries and their functions?
They help with quicker filtration (#2 fastest). They contain pores to do that and are located in the choroid plexus, endocrine organs, and kidneys
What are sinusoids capillaries and their functions?
They are capillaries that are larger and more permeable that allow blood cells and huge substances to go through by gaps between adjacent cells.
Where are continuous, fenestrated, and sinusoid capillaries located?
Continuous: in tissues EXCEPT cartilage and epithelia
Fenestrated: choroid plexus, endocrine organs, and kidneys
Sinusoids: Liver, bone marrow, spleen
How do you calculate pulse pressure?
systolic pressure MINUS the diastolic pressure
systolic pressure - diastolic pressure
What is a normal pulse pressure for a heart at rest?
40mmHg or lower
Explain what vascular resistance is.
It is the friction caused by the blood and the wall of the vessel. The opposition of blood flow as it goes through the vessel
What blood vessels are most responsible for vascular resistance? WHY?
Arterioles, because they are so small
How does vascular resistance affect blood pressure in the largest arteries?
Basically arteries are wide, then the blood flows to the distribution arteries which are narrower and slow down (back pressure increases, and resistance), and then you get to the arterioles which are even narrower and increases back pressure and resistance.
More resistance = higher blood pressure
Where is blood velocity highest in the body?
Arteries
Where is blood velocity lowest in the body?
Capillary beds
Why is fast/high blood velocity in the arteries and slow/low blood velocity in the capillaries super important?
Arteries: it ensures efficient delivery of oxygen and nutrients to tissues throughout the body by rapidly transporting blood from the heart to the smaller blood vessels
Capillaries: Because allows time for the exchange of gases and nutrients
Explain what blood colloid osmotic pressure (BCOP) is.
An attracting pressure caused by Albumin in the capillaries that attracts Na+ ions and water back into the capillary REABSORBS (-25mmHg)
Explain what capillary hydrostatic pressure (CHP) is.
Water and small solutes forced out of the capillary value is 35-40mmHg
Explain what net filtration pressure (NFP) is.
It is the difference between CHP and BCOP
CHP - BCOP
What values are normal for blood colloid osmotic pressure (BCOP), capillary hydrostatic pressure (CHP), and net filtration pressure (NFP)?
blood colloid osmotic pressure (BCOP)- (-25mmHg)
capillary hydrostatic pressure (CHP)- 35-40mmHg
net filtration pressure (NFP)- -7mmHg
What is the role of albumin with regards to net filtration pressure?
It attracts Na+ ions which attracts water and reabsorbs it back into the capillaries
What is pulmonary blood pressure?
the pressure within the arteries of the lungs
Why is pulmonary blood pressure levels so low?
To prevent fluid filtration into the lungs
Explain what autoregulation of blood flow is.
ability of an organ to maintain blood flow at a nearly constant rate despite changes in arterial perfusion pressure
What role does nitric oxide have in autoregulation of blood flow?
It dilates the blood vessels
How does aldosterone affect blood pressure?
INCREASES BLOOD PRESSURE by keeping sodium in the kidneys and constricts arterioles
How does ADH hormone affect blood pressure?
It does vasoconstriction by reabsorbing water from the kidneys and INCREASES BLOOD PRESSURE
How does natriuretic peptide affect blood pressure?
It gets rid of sodium in the kidneys which causes water to get excreted as well and it decreases the blood pressure
How does erythropoietin affect blood pressure?
It causes vasoconstriction and production of red blood cells and it causes an INCREASES BLOOD PRESSURE
How does epinephrine and norepinephrine affect blood pressure?
Epinephrine: Vasoconstricts organs that don’t need blood during flight of fight INCREASES BLOOD PRESSURE
Norepinephrine: Vasodilates in places in the body that need blood during flight or fight INCREASES BLOOD PRESSURE
What would happen to the systolic and diastolic pressure if there was less elastic rebound in the arteries? (the walls are stiffer)
Systolic pressure would be increased and the diastolic pressure would be decreased
How do the skeletal muscle pump and the respiratory pump work?
Skeletal muscle pump: you push blood up to the heart when your muscle contracts. Then when it is relaxed the blood comes back down but the valves in the veins close so it doesn’t go down farther and negate the work it made getting it up to the heart. So it goes from valve to valve every time a muscle contracts and relaxes until it reaches the heart. (same thing with respiratory pump)
Respiratory pump: Same thing as the skeletal muscle pump but when you inhale and exhale
What are the 4 things that resist blood flow?
Three things that resist blood flow
1. Radius of the blood vessels (diameter, smaller diameter = more resistance, large diameter = less resistance) EFFECTS IT THE MOST
2. Length of the vessel (longer vessel it is hard/more resistance, shorter = less resistance)
3. Viscosity of blood (thickness of blood, thicker = more resistance, thinner = less resistance)
4. Turbulence (flow of the blood is disturbed by the plaque in the blood vessels and even the flow is disturbed after going past the plaque in the blood vessels)
