EXAM 2 Vascular System Flashcards
Arteriolar smooth muscle contraction results in increased vascular resistance, reducing ______.
capillary perfusion
Most capillaries are between __ and ___ µm in diameter
5-10µm
blushing is related to _____.
precapillary sphincters
Capillaries can dilate with ______.
increased arteriolar pressure
Size of capillaries are just big enough to allow _____ through in “single file”.
red blood cells
The entrance into capillary beds are surrounded by ______.
smooth muscle precapillary sphincters
precapillary sphincters are Smooth muscle that responds to ______ substances
vasoconstrictor
capillary pressure is low or high?
low
pressure inside the capillary
35 to 15 mmHg
% of the blood volume is in capillaries
5%
What exchanges in the capillaries?
gases, nutrients, and wastes
how is the flow in capillaries?
Flow is slow and
continuous
Capillaries allow transport by ____.
vesicle movement
Three layers of artery and vein
Tunica Externa (adventitia)
Tunica Media
Tunica Intima
Strong outer covering of arteries and veins
Consists of connective tissues (collagen and elastic fibers on external elastic lamina)
Tunica Externa (adventitia)
Middle layers of smooth muscle and elastic fibers
Thicker in arteries than veins
Tunica Media
Inner layer in direct contact with the blood
Elastic basement membrane (elastic lamina) covered by endothelial cells
Tunica Intima
Each layer of artery and vein is separated from the next by ______ (external and internal)
elastic lamina
Walls of large arteries contain a large amount of what two things?
smooth muscle (media) elastic tissue (thick elastic laminas)
Laminas stretch during _____.
systole
Laminas recoil during _____.
diastole
Vascular smooth muscle of arteries is innervated by___.
SNS
is PNS involved with innervation of arteries?
no
major site of vascular resistance (BP)
arterioles
Constriction of artery increases
________.
resistance and blood pressure
dilation of artery decreases ____.
blood pressure
what cushion the cardiac pulsation and convert intermittent blood flow to steady flow
arteries
Aorta expands during ______ to accommodate flow (SV)
systole
Aorta recoils during _____ to maintain pressure and arterial flow
diastole
large artery Pressure increases during _____
systole (systolic BP)
large artery Pressure is partially maintained during ______ by elastic recoil
diastole (diastolic BP)
Arteriolar smooth muscle contraction results in_________.
increased vascular resistance
which reduces capillary perfusion
Most capillaries are between__ and ___in diameter
5 and 10 µm
size of capillaries is sufficient enough to let in ___.
red blood cells
Capillaries can dilate with _____.
increased arteriolar pressure
The entrance into capillary beds are surrounded by _______.
smooth muscle precapillary sphincters
Smooth muscle that responds to vasoconstrictor substances
precapillary sphincters
Pressure inside capillary is ___ (low pressure)
35 to 15 mmHg
what % of the blood volume is in capillaries
5%
exchange of what 3 things occur in capillaries?
Exchange of gases, nutrients, and wastes
how is flow in capillaries?
slow and continuous
example of capillary movement through both fenestrations and incomplete basement membranes
Sinuosoidal
Fenestrations regulate _____.
size of molecules passing through them
these are readily permeable across capillary endothelial cells and basement membranes
O2, CO2 and other gases
these are freely transportable across capillary (except BBB)
Nutrients (FA, AA, vitamins, minerals)
Cells and large proteins held inside the ___.
capillary lumen
Lipoprotein particles (chylomicrons, LDL, HDL, VLDL) are metabolized where?
endothelial surface via lipoprotein receptors, enzymes
ex: lipoprotein lipase
Contain relatively little smooth muscle, but can constrict with sympathetic stimulation and endothelins
veins and venules
Midsize and large veins have _____ to prevent retrograde (backward) flow
one-way valves
are one-way valves present in great veins?
no
these are not present in the very small veins and venules, the “great” veins (e.g., vena cava), or the veins from the brain and viscera
one-way valves
what compresses veins and forces blood to flow through one-way valves towards the heart
Skeletal muscle contraction
Excessive pressures within veins can cause ____.
failure of valves and/or dilatation of veins (varicose veins)
these have highest compliance
veins
vessel that can contain largest amount of blood volume
Veins
referred to as “capacitance vessels”
veins
the smaller the vessel, the ___ the blood flows through
slower
fluid balance Is maintained by
Hydrostatic (blood pressure) colloid osmotic (blood protein content) Endothelial junction integrity
Collect plasma from the interstitial spaces and return to the blood
lymphatic vessels
lymphatic vessels Begin with
closed-ended vessels with porous walls
lymphatic vessels Coalesce into larger vessels and have what to assure single direction flow?
one-way valves
where are Lymph nodes located?
along the course of flow and lymph passes through
where do lymphatic vessels end?
thoracic duct
where does the thoracic duct empty?
left subclavian vein
what forces lymph to flow in one direction due to the presence of one-way valves (same process as veins)
Skeletal muscle contraction
Blood pressure affected by (5)
- Arterial resistance (constriction, stenosis)
- Products of the endothelium
- Arterial compliance (ability to stretch and recoil)
- Hormonal control
- Central (CNS) and autonomic control (nervous input, circulating effectors)
Anytime we injure endothelial cells what increases?
blood pressure
Healthy Endothelium has 2 things
Vasodilators
Antithrombotic factors
examples of Antithrombotic factors
prostacyclin, thrombomodulin, antithrombin, plasminogen activator, heparin
examples of vasodilators
nitric oxide [NO], prostacyclin
“Injured” Endothelium has 2 things
Vasoconstrictors
Prothrombotic factors
Prothrombotic factors examples
von Willebrand’s factor, thromboxane, factor V, thromboplastin, platelet activating factor, plasminogen activator inhibitor
Vasoconstrictors examples
ACE, thromboxanes, leukotrienes, endothelin
the predominant neurotransmitters affecting vascular tone
Norepinephrine (synaptic) and epinephrine (adrenal)
sympathetic vascular control deals with
Norepinephrine (synaptic) and epinephrine (adrenal) affecting vascular tone
Alpha-adreno receptors
Associated mainly with
with increased contractibility of vascular smooth muscle and intestinal relaxation
Alpha1 (α1) receptor stimulation results in
smooth muscle contraction in peripheral blood vessels
Alpha2 (α2 ) receptor stimulation stimulation results in
in relaxation of GI smooth muscle and minor effects on blood vessel smooth muscle (contractile and dilatory effects)
Beta1 (β1) receptor stimulation results in
cardiac stimulation and lipolysis
Beta2 (β2 ) receptor stimulation results in
bronchodilation, relaxation of skeletal muscle blood vessels, and muscle glycogenolysis
Beta-adrenoreceptors
Associated with
vasodilation and relaxation of nonintestinal smooth muscle and cardiac stimulation
Hypertension in diabetes comes from
endothelial cell dysfunction
Epinephrine and norepinephrine
are from the ___,
adrenal medulla
when are Naturetic peptides
produced?
with atrial and ventricular stretch
reunions comes from the ___.
kidney
angiotensin is a plasma protein from the ___.
liver
aldosterone comes from the ____.
adrenal cortex
ADH/ Vasopressin is from the ____.
posterior pituitary
Cuff pressure > systolic BP – what is sound?
No sound (no arterial flow)
The first sound heard in Bp
is just below peak systolic BP
when taking BP, Sounds are heard while ___.
cuff pressure < systolic BP but > diastolic BP
when taking BP, when does sound disappear?
when cuff pressure < diastolic BP (no flow resistance or turbulance)
what maintains higher diastolic pressure?
compliance
gravity affects what pressure?
venous pressure