Test 2 Vascular System Flashcards
What cell lines a blood vessel?
endothelial cells- form barrier against blood movement
What are the 3 layers of blood vessels?
- Tunica Externa (adventitia)
- Strong outer covering of arteries and veins
- Consists of connective tissues (collagen and elastic fibers of external elastic lamina) - Tunica Media (media)
- Middle layers of smooth muscle and elastic fibers
- Thicker in arteries than veins - Tunica Intima (intima)
- Inner layer in direct contact with the blood
- Elastic basement membrane (inner elastic lamina) covered by endothelial cells
What separates the layers of blood vessels?
Each layer separated from the next by elastic lamina (external and internal)
Primary difference between arteries and veins is amount of ____ and _____.
smooth muscle (more in arteries) and elastic lamina (thicker in arteries)
Walls of large and medium sized arteries contain a large amount of ____ and _____.
smooth muscle (media) and elastic tissue (thick elastic lamina)
Laminas passively stretch during _____ and recoil during _____.
systole; diastole
Vascular smooth muscle is influenced by____, which means there is no ____innervation.
SNS (constrict);
PNS
What are the major site of vascular resistance (blood pressure regulation)? What does this do to BP?
arterioles
***Active constriction increases
BP, dilation decreases BP
Arteriolar smooth muscle contraction results in ____, increasing pressure in the proximal arteries (i.e., overall increased BP) while reducing blood flow through distal capillaries (i.e., reduced tissue perfusion)
increased vascular resistance
Most capillaries are between ____ µm in diameter
5 and 10
Capillaries are sufficient to permit ____ (~5 µm) to squeeze through in “single file“
red blood cells
Capillaries can ____ dilate with increased arteriolar pressure
passively
The entrance into capillary beds are surrounded by smooth muscle, called ______
precapillary sphincters
Precapillary schinters respond to _____ substances (locally released or circulating)
vasoconstrictor
What do the precapillary schinters control through capillary beds?
blood flow
Is the pressure inside capillaries high or low?
low
therefore flow is slow and continuous
Only ___ % of all blood volume is in capillaries
5
What do capillaries carry?
Exchange of gases, nutrients, and wastes
Capillaries allow movement from blood into tissue spaces in 3 ways:
- Vesicle movement (“continuous” capillaries, e.g., BBB)
- Fenestrations (pores) between cells (e.g., glomerular)
Fenestrations regulate size of molecules passing through them - Fenestrations and incomplete basement membranes (“Sinuosoidal” capillaries, e.g., liver and many lymphoid organs)
O2, CO2 and other gases are readily permeable or impermeable across all capillary endothelial cells and basement membranes
permeable
Nutrients (FA, AA, vitamins, minerals) freely move across ____ and _____ (except continuous, only by receptor-mediated vesicular transport)
fenestrated and sinusoidal capillaries
____ are metabolized by endothelial cell lipoprotein receptors and enzymes (e.g., lipoprotein lipase)
Lipoprotein particles
____ and _____ are held inside capillary lumen (except when specifically transported or with “leaky” capillary walls)
cells and most proteins
_____ are only slightly thicker than capillary walls, easily distended
Venule walls
Veins contain relatively little smooth muscle but can constrict with what?
with sympathetic stimulation and cytokines
Midsize and large veins have ______ to prevent retrograde (backward) blood flow
one-way valves
____ are not present in the very small veins and venules or in the “great” veins (e.g., vena cava), or the veins from the brain and viscera
valves
Skeletal muscle contraction compresses ____ and forces blood to flow through one-way valves towards the heart
veins
*Compression is what is important for blood flow so artificial compression can be achieved
Excessive pressures within veins can cause ________.
failure of valves and/or dilatation of veins (varicose veins)
(Large) Arteries cushion the cardiac pulsation and convert pulsatile blood flow to _____.
steady flow
Aorta passively expands during ____ to accommodate blood entry (SV) and passively recoils during _____ to maintain pressure and arterial flow
sytole;
diastole
Pressure increases during systole (systolic BP) and is partially maintained during diastole (diastolic BP) by….
elastic recoil
What are great veins?
femoral veins and vena cava veins
Veins have highest compliance (ability to stretch and recoil) and contain the largest volume within the vascular system so they are called
“capacitance vessels”
____ collect plasma from the interstitial spaces and return to the blood
lymphatic vessels
Lymphatic vessels begin with ____ or ____ vessels with porous walls
closed or blind-ended
Lymphatic vessels coalesce into larger vessels and have ____ to assure single direction flow (like veins)
one-way valves
_____ are located along the length of lymph vessels
Lymph nodes (LN)
*Lymph nodes (LN)
Lymphatic vessels end at the ___ which empties lymph into the blood into the ____
thoracic duct;
left subclavian vein
Like veins, skeletal muscle contraction compresses _____ and forces lymph to flow in one direction due to the presence of one-way valves
lymphatic vessels
What are 5 things that affect blood pressure?
- Arterial resistance (constriction / dilation, stenosis)
- Arterial compliance (ability to stretch and recoil)
- Products of the endothelium
- Hormonal control
- Central (CNS) and autonomic control (nervous input, circulating effectors)
What is the most elastic vessel?
aorta
*smooth muscle can stretch and rebound
What vessel controls blood pressure?
arteriole
Do the smaller vessels or greater veins have a higher cross sectional area?
smaller like capillaries so more gas exchange
As we age what happens with BP?
Systolic pressure climbs and diastolic falls. Stiffening of the elastic lamina
What are the three influences of the movement of fluid (fluid balance?
Forces: Hydrostatic (blood pressure) is always higher within the blood vessels and colloid osmotic (blood protein content) is trying to hold fluid inside vessel bc more protein outside
Other: Endothelial junction integrity -disruption of fluid flow btw tissues and capillaries (i.e., endothelial leak)
T or F: Elastic lamina are not important when it comes to heart disease.
False. They are very important to avoiding constricted and hardened vessels
Relaxer of smooth muscle
vasodilators
What is always producing nitric oxide and prostacyclin(antithrombotic-reduces blood clots) if there is healthy endothelium?
vasodilators
What produces Angiotensin converting enzyme [ACE], thromboxanes, leukotrienes, endothelin in injured endothelium?
vasoconstrictors
Who is more likely to get a blood clot?
smoker bc they have injured endothelium
What are 4 hormones that regulate blood pressure?
- Epinephrine and norepinephrine
- From the adrenal medulla - Naturetic(sodium) peptides
- Produced with atrial and ventricular stretch (atrial naturetic peptide, ANP, and B-type naturetic peptide, BNP) - Renin-angiotensin-aldosterone
- Renin from the kidney
- Angiotensin, a plasma protein from the liver (from angiotensinogen)
- Aldosterone from the adrenal cortex - Vasopressin (Antidiuretic Hormone, ADH)
- ADH from the posterior pituitary
Parasympathetic stimulation results in _____
decreased HR (reduced SA and AV node pacing)
______ stimulation results in increased HR (increased SA and AV node pacing) and increased cardiomyocyte contractility
sympathetic
____ and _____ are the predominant neurotransmitters affecting vascular tone, both cause vasoconstriction (increase vascular resistance and BP)
Norepinephrine (synaptic) and epinephrine (adrenal)
What is the purpose of Vasopressin (ADH)?
increases blood pressure
What controls central and autonomic blood pressure control?
brainstem
What is the only force to move blood through venous system?
muscle contractibility
What is venous pooling? What allows that to occur?
pooling the blood to a location in the body;
gravity plays a huge part in bringing blood back to heart
Where is zero venous pressure point?
right atrium
T or F: you need to raise a body part above zero venous pressure point when it is swelling bc there is no pressure beyond that point
true
Why will your legs start to swell when you stand vertical for a long period of time?
gravity causes the pressure to be higher. the taller you are the higher the pressure. muscles contract to bring the blood back to the heart so you need to move around
Why does the ventricles have the largest pressure differential?***
the elastic lamina
60% of blood is in what system?
venous system
All vascular sounds are from what?
vibrations usually turbulent flow
Where do you put your stethoscope when listening for blood pressure?
over brachial artery (medial side of arm)
Explain the process of listening to blood pressure: Korotkoff sounds(bruit)
- Cuff pressure > systolic BP – no sound (no arterial flow of blood going through vessel)
- The first sound is heard just below peak systolic BP
- Sounds are heard while cuff pressure < systolic BP but > diastolic BP
- Sound disappears when cuff pressure < diastolic BP (no flow resistance or turbulance)
Difference btw murmur and bruit.
both audible turbulence but murmur in the heart specifically
