Vascular Flashcards
arteries
carry blood away from the heart
branch
diverge
fork as they form smaller ones
Veins
carry blood twd the heart
join, merge, and converge into successive layers approaching heart
In pulmonary circulation how do arteries function?
Instead of carrying oxygenated blood they carry deoxygenated blood to the lungs
In pulm ciruit, how do veins function ?
Instead of carrying deoxygenated blood they carry oxygenated blood to from lungs to heart
Lumen
central blood-containing space covered by the tunics
Tunics
the walls of blood vessels, except smallest ones, have three layers and surround the lumen
(coverings)
tunica intima
innermost tunic
intimate contact with the blood in the lumen
What does the tunica intima contain?
simple squamous (endothelium tissue) epithelium that lines the lumen of all vessels
What is the role of the endothelium tissue ?
continuous with the endocardial lining of the heart, and its flat cells fit closely together, forming a slick surface that minimizes friction as blood moves through the lumen.
What is the subendothelial layer and its purpose?
In vessels larger than 1mm, has basement layer and loose connective tissue that supports the endothelium
Tunica media
middle tunic that is mostly circular arranged muscle cells and sheets of elastin
How is the smooth muscle cells activity of the tunica media regulated?
It is regulated by the sympathetic vasomotor nerve fibers of the ANS and bunch of chemicals
What does tunica media regulation cause?
Vasconstriction or vasodilation
Vasoconstriction
lumen diameter decreases as the smooth muscle contracts
vasodilation
lumen diameter increases as the smooth muscle relaxes
Why is the activity of the tunica media important?
Tunica medica is critical in regulating circulatory dynamics because small changes in vessel diameter greatly influence blood flow and blood pressure
What is the bulkiest tunic layer in the arteries and why so?
Tunica media since it chiefly responsible for maintaining blood pressure and circulation
Tunic externa
outermost layer of blood vessel wall
Tunica adventitia
same as tunic externa
means coming from outside
What makes up the tunica externa?
composed largely of loosely woven collagen fibers that protect and reinforce vessel and anchor it to surrounding structures
What is the tunica externa infiltrated with?
nerve fibers, lymphatic vessels, and in larger VEINS, a network of elastic fibers
What does the tunica externa have in large vessels?
Vasa vasorum, tiny system of blood vessels
“vessels of the vessels”
function of vasa vasorum
nourish more external tissues of the blood vessel wall
What gets the most nutrients?
innermost/luminal portion of the vessel obtains nutrients directly from blood in the lumen
What do the tunics all vary?
length, diameter, wall thickness, and tissue makeup
What are the three groups that arteries can be divided into
in regards to relative size and function?
elastic arteries
muscular arteries
arterioles
Elastic arteries
thick-walled arteries near the heart like the aorta and it major branches, and are the largest in diameter and most elastic, low resistance pathways that conduct blood from the heart to medium sized arteries, and for that they are sometimes called conducting arteries
What do elastic arteries have most of than any other arteries?
elastin
What is present in all three tunics, and which tunic has the most?
elastin, tunica media
Function of elastic arteries
pressure reservoirs, expanding and recoiling as the heart ejects blood, so that blood flows continusouly rather than starting and stopping with pulsating rhythm of the heartbeat
How does atherosclerosis impact elastic arteries?
blood flows more intermittently (stop and go)
What would happen to arteries if they weren’t elastic?
Without the pressure smoothing effect of the elastic arteries, the walls of arteries throughout body would experience higher pressures, and would eventually weaken and may balloon or burst
Muscular arteries
distal to elastic arteries
deliver blood to specific body organs (sometimes called distributing arteries for that reason)
size of muscular arteries
internal diameter from that of a little finger to that of a pencil lead
muscular arteries have the thickest what
media tunica
Tunica media in muscular artery traits
more smooth muscle and less elastic tissue than elastic arteries
Since they have a unique tunica media, muscular arteries have more of an active role in what?
vasoconstriction and less stretchable (distensible)
What on each face of tunica media in muscular arteries?
elastic membrane
larger arterioles and their tunics
larger ones have all three, but their tunica media is chiefly smooth muscle with a few scattered elastic fibers
smaller arterioles
lead into cap beds, little more than a single layer of smooth muscle cells spiraling around endothelial lining
arteriole diameter determines what?
varies in change to response to changing neural, hormonal, and local chemical influences
What happens when the arterioles constrict?
the tissues served are largely bypassed
What happens when the arterioles dilate??
blood flow into the local capillaries increases dramatically
What the smallest blood vessels? They r microscopic
capillaries
Capillaries consist of what?
thin tunica intima, and sometimes one endothelial cell forms the entire circumference of the capillary wall
Pericytes
at strategic points along the outer surface of some capillaries are these spider shaped, smooth muscle-like cells that stabilize the capillary wall and help control capillary permeability
cap size
large enough to allow red blood cells in single file
Tendons and ligaments are what?
poorly vascularized
Cartilage and epithelia lack?
caps, but receive nutrients from blood vessels through nearby connective tissues
AVASCULAR cornea and lens of eye receive nutrients from what?
aqueous humor
What are capillaries role ideally suited for?
exchange of materials such as gases, nutrients, hormones .. . between the blood and interstitial fluid
what are the three structures of capillaries?
continuous
fenestrated
sinusoid
Continuous capilliaries
abundant in skin and muscles, most common
Continuous in the sense that their endothelial cells are joined together by tight junctions
What do tight junctions in continuous caps do?
providing an uninterrupted lining, but these junctions usually incomplete and leave gaps of unjoined membrane, intercellular clefts
Intercellular clefts in continuous caps
gaps of unjoined membranes (tight junctions) that are large enough to allow limited passage of fluids and small solutes
Brain caps in cont caps
tight junctions are complete and extend the entire perimeter of endothelial cells, constituting structural basis of blood brain barier (no intercellular cleft makes it unique)
Fenestrated caps
are like continuous variety except that the endothelial cells in fenestrated capillaries are riddled with oval pores, or fenestrations (fenestra=window)
What covers fenestrations?
delicate membranes, or diaphragm
What does fenestrated have differently from continuous cap structure?
more permeable to fluids and small solutes than cont caps
Where are fenestrated capillaries found?
anywhere active capillary absorption or filtrate formation occurs
example location fenestrated caps
small intestines receive nutrients from digested food, and those in endocrine organs allow hormones rapid entry into the blood, kidneys-open pores where rapid filtration of blood plasma is essential
Sinusoid caps (sinusoids)
highly modified, leaky caps found only in the liver, bone marrow, spleen, and adrenal medulla
sinusoids desrciption
large, irregularly shaped lumens and are fenestrated
sinusoids endothelial have
fewer tight junctions and larger intercellular clefts than ordinary capillaries
What do the structural adaptations in sinusoids allow?
large molecules and even blood cells to pass between the blood and surrounding tissues
sinusoids in liver
endothelial is discontinuous, and lining includes stellate macrophages (hepatic macrophages)
purpose/f(x) of stellate macrophages
remove and destroy any bacteria
sinusoids in spleen
phagocytes located just outside the sinusoid stick cytoplasmic extensions through the intercellular clefts into the sinusoid lumen to get their prey
How does blood flow in sinusoids?
sluggishly through sinusoid channels since it allows time for it be modified in various ways.
Capilary beds
caps form these interweaving networks
Microcirculation
blood flow from arteriole to a venule
What blood vessels comprise the cap bed?
vascular shunt
true capillaries
vascular shunt
metarteriole-thoroughfare channel
a short vessel that directly connects the arteriole and venule at opposite ends of the beds
True capillaries
actual exchange vessels
terminal arteriole
feeding bed leads into a metarteriole that is continuous with the thoroughfare channel that joins the postcapilary venule
metarteriole
vessel structurally intermediate btw an arteriole and a capillary
thoroughfare channel
intermediate btw a capilary and a venule
postcapillary venule
drains the bed
What determines amount of true capillaries?
organ or tissue served
how the true cap situate in the body?
branch off the metarteriole, the proximal end of shunt, and return to the thoroughfare channel (distal end of shunt); but sometimes they derive from the terminal arteriole and empty into the venule
precapillary sphincter
cuff of smooth muscle fibers that surrounds the root of each true capillary at the metarteriole
precap sphincter function
acts as a valve to regulate blood flow into the capillary
Blood flow through a terminal arteriole flows
through true cap or through the shunt
What happens when the precapillary sphincters are relaxed/open?
blood flows through true capillaries and takes a role in exchanges w/ tissue cells
What happens when precap sphincters are constricted/closed?
blood flows through the shunts and bypasses the tissue cells
What regulates the amount of blood entering a cap bed?
local chemical conditions and arteriolar vasomotor nerve fibers
when bed is flooded with blood or completely bypassed it depends on what?
conditions in body or specific organ
Venules
Capillaries untie to form
What is the smallest venule?
postcapillary venule
What does postcapilary venule consist of?
entirely endolethium around which the pericytes congregate , extremely porous, and fluid and white blood cells move easily from the bloodstream through their walls
larger venules
have one or 2 layers of smooth muscle cells (tunic media and thin tunica externa)
Veins are formed by
venules
vein anatomy
3 distinct tunics, thinner walls and their lumens r larger than those corresponding arteries. Lumens split like
what is there relatively little of in veins?
smooth muscle/elastin in tunica media that poorly developed and tends to be thin even in largest veins
Tunica externa in veins
is heaviest wall layer, consisting of thick longitudinal bundles of collagen fibers and elastic networks; often several times thicker than tunica media
Large veins (venue cava) tunica externa size
even thicker due to longitudinal bands of smooth muscle
Why are veins called capacitance vessels and blood reservoirs?
hold 65% of body’s blood supply at any time, even so they are partially filled normally
Why can the vein walls be thinner than arteries’ without danger to of bursting ?
blood pressure in veins is low
what adaptation of low pressure do to veins and why so?
Ensure that veins returns blood back to heart same rate it was pumped into circulation
larger lumen in lumen offer little resistance to blood flow
Venous valves
prevent back flow
formed from folds of the tunica intima, resemble semilunar valves of the heart in both structure and f(x)
Where venous valves most abundant?
in veins of limbs, where gravity opposes the upward bloodflow
Where are venous valves unlikely found?
absent in veins of thoracic and abdominal body cavities
varicose veins
veins that are twisted and dilated due to incompetent (leaky) valves
Venous sinuses
coronary sinus
dural venous sinuses
highly specialized, flattened veins with extremely thin walls composed only of endothelium
What venous sinuses supported by?
tissues surrounding them rather than additional tunics
Vascular anastomoses
blood vessels from special interconnections
arterial anastomoses
most organs receive blood from more than one arterial branch and arteries supplying the same area merge and form alternate paths
Alternate paths in anastomoses
collateral channels direct blood to certain body region
What happens if there a branch is cut or there is clot?
collateral channels can provide enough blood to area often
Where do arterial anastomoses occur?
around joints where active movement may hinder blood flow through one channel, and also they common in abdominal organs, heart, and brain
What organs do not have anastomoses?
arteries that supply the retina, kidneys, and spleen or they have poorly developed collateral circulation
What happens to the organs that do not have anastomoses when blood flow is interupted?
cells that supply such vessel die
arteriovenous anastomoses
metarteriole-thoroughfare channel shunts of capillary beds that connect arterioles and venules
what interconnects more freely veins or arteries?
veins interconnect more freely
what are more common and abundant arterial or venous anastomose?
venous anastomoses are more common and abundant
Blood flow
volume of blood flowing through a vessel, an organ, or the entire circulate in a give period (ml/min)
= to Cardiac output and is constant during resting
Blood pressure
force/area exerted on a vessel wall by the contained blood (mm Hg)
bp and pressure gradient
the differences in bp within vascular sys that provides driving force that keeps blood moving always high to low throughout body
Resistance
is opposition to flow and measure of the amount of friction blood encounters as it passes through the vessels
peripheral resistance
most friction is dealt with in the peripheral (systemic) circulation
3 sources of resistance in
blood viscosity, vessel length, and vessel diameter
blood viscosity
internal resistance to flow that exists in all fluids (viscosity) and is related to the thickness or stickiness in fluid
why is blood more viscous than h2o?
blood has formed elements and plasma proteins, it flows more slowly under same conditions
what can increase blood viscosity/resitance?
polycythemia (excessive numbers of red blood cells)
Blood vessel length
the longer the vessel, the greater the resistance
blood vessel diameter
changes frequently and alters peripheral resistance
laminar flow or streamlining
the relative speed and position of fluid in diff regions of the tube’s cross sectioning remain constant
The smaller the tube the great the friction since more fluid contacts the tube wall where its movement is blocked
How does resistance vary?
inversely with the fourth power of the vessel radius
why do the arterioles change dramatically in diameter?
they respond to neural and chemical curls, are major determinants of peripheral resistance unlike the large arteries close to the heart
turbulent flow
irregular fluid motion where blood from the different laminae mixes, increasing resistance dramatically, is onset by arteriosclerosis
What is blood flow directly proportional to?
to difference in blood pressure between two point in circulation which is bp, hydrostatic pressure, gradient. When pressure increases, bf speeds up
Blow flow is inversely propotional to?
PERIPHERAL RESISTANCE R in systemic circulation; if resistance increases, BF decreases
What does pressure result from?
when flow is opposed by R
What vessel offers the greatest resistant to blood flow?
arterioles
arterial blood pressure
how much the elastic arteries close to the heart can stretch (compliance/distensibility)
volume of blood forced into them at any time
Why is blood pressure pulsatile and what does that word even mean?
the amount of blood leaving and entering heart are not equal/constant, and that means a rise and fall in a reg fashion in the elastic arteries near the heart
ventricular contraction
systolic pressure
blood moves into the arterial bed since the pressure in the aorta is higher than the pressure in the more distal vessels
WHAT HAPPENS DURING DIASTOLE? diastolic pressure
the aortic valves closes preventing blood from flowing back into the heart; wall of aorta recoil maintaining sufficient pressure tp keep blood flowing fwd to its lowest levels
pulse pressure
the difference btw systolic and diastolic pressure
Mean arterial pressure (MAP)
aortic pressure fluctuates up and down with each heartbeat is important to this
the pressure that propels blood to the tissues
why low cap pressures necessary?
capillaries are fragile and high pressures rupture them
most capillaries are extremely permeable and thus even the low capillary pressure can force solute containing fluids (filtrate) out of blood stream into the interstitial space
venous blood pressure
is different from arterial bp
steady and changes very little during cardiac cycle
what happens when a vein is cut and how is it different than artery being cut?
different than artery
for vein, blood flows evenly from wound
for artery, spurts blood
This is because veins have lower pressure, high R
muscular pump
skel muscle activity
as skel muscle surrounding deep veins contract and relax, they “milk” blood two the heart and once blood passes each successive valve like the circles in inferno, it can’t flow back
fainting after standing for long time periods cuz it reduces venous return
resp pump
moves blood up two heart as pressure changes in the ventral body cavity during breathing
As we inhale, abdominal pressure increases, squeezing local veins aand forcing blood two the heart
at the same time, the pressure in the chest decreases allowing thoracic veins to expand and speeding blood entry into right atrium
Sympathetic venoconstrction
reduces volume of blood in veins (capacitance vessels)
as the layer of smooth muscle around veins constricts under sympathetic ctrl, venous volume is reduced and blood is pushed two the heart
What do muscle pumpp, resp pump, and sympathetic venoconstriction do?
increase venous return which increases SV by the Frank-starling mechanism thus increasing CO
what maintains blood pressure?
cns, CO, R, blood volume
blood varies ______ with CO (and blood volume) and R
directly
what is in charge of heart most of the time (resting heart rate that is )
cardioinhiborty center of medulla oblongatta
short-term regulation of bp
by nervous system and bloodborne hormones alters bp by changing peripheral resistance and CO
long-term reg bp
alters blood volume via kidneys
Short term regulation functions how
neural ctrls alter both CO and R
2 main goals of neural curls of peripheral R
maintainin adq MAP by changing blood vessel diameter on a moment basis, under low blood volume, all vessels except those supplying heart and brain are constricted to allow as much blood as possible to flow to those two vital organs
altering blood distribution to respond to specific demands of various organs
How do most neural curls operate ?
via reflex arcs involving barorecptors and associated afferent fibers; these reflexes are integrated in the cardiovascular center of the medulla, and their output travels via autonomic fibers to the heart and vascular smooth muscle.
What are the chemical inputs in neural ctrl?
chemoreceptors and higher brain centers also influence the neural ctrl mech
what ctrls diameter of blood vessel????
cardiovascular centers and vasomotor centers
vasomotor fibers
the vasomotor center transmits fibers impulses at a fairly steady rate along the sympathetic efferents
what do the vasomotor fibers do?
fibers exit T1 through L2 levels of spinal cord and innervate the smooth muscle of blood vessels, mainly invervate arterioles
vasomotor tone
arterioles are almost always state of moderate constriction
what does any increase in sypmthatetic activity do?
yields generalized vasoconstriciton and raises bp
modify inputs of cardiovascular center
baroreceptors
chemoreceptors
higher brain receptors
baroreceptors
pressure sensitive mechanoreceptors that respond to changes in arterial pressure and stretch
arterial blood pressure increase activates it
stretch receptors
they decrease BP
chemoreceptors
receptors that respond to changes in blood lvld of co2, H+, O
where are baroreceptors located?
carotid sinuses
AORTIC ARCH
walls of nearly every large artery of the neck and thorax
carotid sinuses
which are dilations in the internal carotid arteries that provide the major blood supply to the brain
arteriolar vasodilation
decreased output from vasomotor center allows arterioles to dilate. as r falls, MAP does
venodialtion
decreased output from vasomotor center makes veins dilate which shifts blood to the venous reservoirs; this decreases venous return and CO
Decreased CO
impulses to the cardiac centers inhibit sympathetic activity and stimulate parasympathetic activity, reducing HR and contractile force. As CO decreases so does MAP
what do barorecptors in the carotid sinus reflex do?
protect blood supply to your brain
barorepctors in aortic reflex?
help maintain adq bp in your systemic circuit
How chemrecptors activated?
When CO2 lvld rises or pH falls or oxygen content of the blood drops sharply
where are the chemrecpts activated and how
aortic arch and large arteries of the neck transmit impulses to the cardioacceltry center which then increases cardiac output,and to the vasomotor center that causes reflex vasoconstriction.
what are the most prominent chemrecptors?
carotid and aortic bodies located close by the baroreceptors in carotid sinuses and aortic arch
chemosrepctors play a larger role in
regulating resp rate than bp
WHAT mediates long term regualtion
renal mechanisms
kidneys help regulate
blood volume
what is a major determinant in blood volume?
CO
What does a sudden drop in BP signals?
internal bleeding and blood volume too low to support normal circulation
direct renal mechanisms
alters blood volume independently of hormones (they don’t rely on hormones to change blood volume)
as blood volume decreases, what else does?
arterial bp decreases
indirect renal mechanism
renin-angiotensin-aldosterome mechanism regulates bp
vital signs (vitals)
pulse, BP, resp rate, and body temp
pulse
transmitted through the arterial tree, artery against a firm tissue is how it is felt
pressure points
pulse points, they are compressed to stop flow into distal tissue during hemorrhage
hemmorrhage
bleeding
systolic pressure where hear what is happening
first point at which a small amount of blood is spurting through constricted artery
sounds of Korotkoff
cuff pressure reduction when sounds get louder and disntct
diastiolic pressure when heard
when sound goes away
tissue perfusion 4 things it does
delievering oxygen and nutrients to tissue cells and removing waste from them
exchangig gases in the lungs
absorbing nutritents from digest tract
forming urine in kidneys
autoregulation
the automatic adjustment of blood flow to each tissue in proportion to the tissues requirements at any instant
What can cause essential/ primary hypertension?
Heredity, Diet, Obesity, Age, Diabetes mellitus, and stress, smoking increase blood pressure
Hypertension: secondary hypertension causes
CHAPS
Cushing's syndrome Hyperaldosteronism [aka Conn's syndrome] Aorta coarctation Phaeochromocytoma Stenosis of renal arteries
Posterior mediastinum: contents
DATES
Descending aorta Azygos and hemiazygous veins Thoracic duct Esophagus Sympathetic trunk/ganglia
Thoracoacromial trunk: branches
"Cadavers Are Dead People": Clavicular Acromial Deltoid Pectoral
Thoracoacromial artery branches
ABCD:
Acromial
Breast (pectoral)
Clavicular
Thoracoacromial artery branches
"CAlifornia Police Department": Clavicular Acromial Pectoral Deltoid
Branches of Internal Iliac Artery
"I Love Going Places In My Very Own Underwear": Ileolumbar Lateral sacral Gluteal (superior and inferior) Pudendal (internal) Inferior vesicle (uterine in females) Middle rectal Vaginal Obturator Umbilical
Internal iliac artery: anterior branches
What Bill admitted to Hilary: "I Milked Our Insatiable Intern's Udders Under the Desk": Inferior gluteal Middle rectal Obturator Inferior vesical artery Internal pudendal artery Umbilical U/D=Uterine artery (female)/ Deferential artery (male)
Internal iliac artery: posterior branch
PILS: Posterior branch Iliolumbar Lateral sacral Superior gluteal
External jugular vein: tributaries
PAST: Posterior external jugular vein Anterior jugular vein Suprascapular vein Transverse cervical vein
> Vascular endothelium: simplified cross-section
LIMA: Lumen Intima Media Adventitia
> Aortic arch: major branch order
"Know your ABC'S": Aortic arch gives rise to: Brachiocephalic trunk left Common Carotid left Subclavian · Beware though trick question of 'What is first branch of aorta?' Technically, it's the coronary arteries.
> Lung lobe numbers:
right vs. left Tricuspid heart valve and tri-lobed lung both on the right side.
Bicuspid and bi-lobed lung both on the left side.
> Ulnar nerve to ulnar artery and radial nerve to radial artery relations Think
“peripheral nerves”:
The ulnar nerve is “ulnar” to the ulnar artery.
Radial nerve is “radial” to the radial artery.
> Superior thyroid artery branches
"May I Softly Squeeze Charlie's Girl?": Muscular Infrahyoid Superior laryngeal Sternomastoid Cricothyroid Glandular
> Female pelvic organs’ blood supply
“3 organs, each get 2 blood supplies”:
Uterus: uterine, vaginal.
Rectum: middle rectal, inferior rectal [inferior rectal is the end of pudendal].
Bladder: superior vesical, inferior vesical.
> Liver: side with ligamentum venosum/ caudate lobe vs. side with quadrate lobe/ ligamentum teres
“VC goes with VC”:
The Venosum and Caudate is on same side as Vena Cava [posterior]. Therefore, quadrate and teres must be on anterior by default.
> Saphenous veins:
path of great vs. small at malleolus “MAGdelaine has varicose veins” [The saphenous veins are important for varicose veins]:
Medial maleolus, Anterior to maleolus, and Great saphenous go together.
Then the opposites of these go together: Small saphenous is posterior to the lateral maleolus.
> Internal jugular vein: tributaries
"Medical Schools Let Confident People In": · From inferior to superior: Middle thyroid Superior thyroid Lingual Common facial Pharyngeal Inferior petrosal sinus
> Heart valves: order in circuit
“First learn a Tricycle, then learn a Bicycle”:
Flow through Tricuspid first, then Bicuspid.
> Thoracic cage: relations to the important venous structures
Behind the sternoclavicular joints: the brachiocephalic veins begin.
Behind the 1st costal cartilage on the right the superior vena cava begins.
Behind the 2nd costal cartilage on the right the azygos vein ends.
Behind the 3rd costal cartilage on the right the superior vena cava ends.
> Descending abdominal aorta: seven divisions
"Sometimes Intestines Get Really Stretched Causing Leakage": Suprarenals [paired] Inferior mesenteric Gonadal [paired] Renals [paired] Superior mesenteric Celiac Lumbar [paired]
> Portal-systemic anastomoses:
main 2 places that retroperitoneals connect into systemic
RetroPeritoneals hook up with Renal and Paravertebral veins.
> Maxillary artery branches
"DAM I AM Piss Drunk But Stupid Drunk I Prefer, Must Phone Alcoholics Anonymous": Deep auricular Anterior tympanic Middle meningeal Inferior alveolar Accessory meningeal Masseteric Pterygoid Deep temporal Buccal Sphenopalatine Descending palatine Infraorbital Posterior superior alveolar Middle superior alveolar Pharyngeal Anterior superior alveolar Artery of the pterygoid canal
> Carotid sheath contents
"I See 10 CC's in the IV": I See (I.C.) = Internal Carotid artery 10 = CN 10 (Vagus nerve) CC = Common Carotid artery IV = Internal Jugular Vein
> Femoral triangle: arrangement of contents
NAVEL: · From lateral hip towards medial navel: Nerve (directly behind sheath) Artery (within sheath) Vein (within sheath) Empty space (between vein and lymph) Lymphatics (with deep inguinal node) · Nerve/Artery/Vein are all called Femoral.
> Femoral triangle: arrangement of nerve, artery, vein
VAN: · From medial to lateral: Vein Artery Nerve · Nerve/Artery/Vein are all called Femoral.
> Inferior vena cava tributaries
"I Like To Rise So High": Illiacs Lumbar Testicular Renal Suprarenal Hepatic vein. · Think of the IVC wanting to rise high up to the heart.
> Cavernous sinus contents O TOM CAT:
O TOM are lateral wall components, in order from superior to inferior.
CA are the components within the sinus, from medial to lateral. CA ends at the level of T from O TOM.
· See diagram.
Occulomotor nerve (III)
Trochlear nerve (IV)
Ophthalmic nerve (V1)
Maxillary nerve (V2)
Carotid artery
Abducent nerve (VI)
T: When written, connects to the T of OTOM.
> Cardiac valves: order in circuit
“TRI berore you BI”:
Tricuspid valve is located in left heart and Bicuspid valve is located in right heart. Blood flows through the tricuspid before bicuspid.
> Subclavian artery branches
"Very Tired Individuals Sip Strong Coffee Served Daily": Vertebral artery Thyrocervical trunk ---Inferior thyroid ---Superficial cervical ---Suprascapular Costocervical ---Superior intercostal ---Deep cervical
> Femoral triangle: contents
NAVY: · In order from lateral to medial: Nerve Artery Vein Y of the groin · Alternatively: Y = Y-fronts [male underwear].
> Axillary artery branches
"Send The Lord to Say A Prayer": · From proximal to distal: Superior thoracic Thoracacromial Lateral thoracic Subscapular Anterior circumflex humeral Posterior circumflex humeral
> Atrioventricular valves
“LAB RAT”:
Left Atrium: Bicuspid
Right Atrium: Tricuspid
> Axillary artery branches
"Screw The Lawyer Save A Patient": Superior thoracic Thoracoacromiol Lateral thoracic Subscapular Anterior circumflex humeral Posterior circumflex humeral Alternatively: "Some Times Life Seems A Pain".
> Axillary artery branches
"Suzy Thompkins Loves Sex, Alcohol, and Pot": · From proximal to distal: Superior thoracic Thoracacromial Lateral thoracic Subscapular Anterior circumflex humeral Posterior circumflex humeral
> Heart valve sequence
"Try Pulling My Aorta": Tricuspid Pulmonary Mitral Aorta
> Coelic trunk: branches
Left Hand Side (LHS):
Left gastric artery
Hepatic artery
Splenic artery
"Suzy Always Lays Flat On Pillows Making Sex Terrific": Superior thyroid Ascending pharyngeal Lingual Facial Occipital Posterior auricular Maxillary Superificial Temporal
> External carotid artery branches
> Brachial artery is medial to biceps tendon
“BAMBI”:
Brachial Artery is Medial to Biceps In elbow.
> External carotid artery branches
"Sister Lucy's Powdered Face Often Attracts Silly Medicos": · Before entering the parotid gland: Superior thyroid Lingual Posterior auricular Facial Occipital Ascending pharyngeal · Ends as: Superficial temporal and Maxillary bifurcating in the in the parotid gland
> External carotid artery branches
"So Long For Acting Old Parenting Means Stability": Superior thyroid Lingual Facial Ascending pharyngeal Occiptal Posterior auricular Maxillary Superficial temporal
> External carotid artery branches
"Some Angry Lady Figured Out PMS": Superior thyroid Ascending pharyngeal Lingual Facial Occipital Posterior auricular Maxillary Superificial temporal
> Brachial artery: recurrent and collateral branches
“I Am Pretty Sexy”
Inferior ulnar collateral artery goes with Anterior ulnar recurrent artery.
Posterior ulnar recurrent artery goes with Superior ulnar collateral artery.
· Alternatively: “I Am Pretty Smart”
> External carotid artery branches
StApLE OPIS: Superior thyroid Ascending pharyngeal Lingual External maxillary (facial) Occipital Posterior auricular Internal maxillary Superficial temporal
> External carotid artery branches
"Sally Ate Lots Of Fresh Produce March Through September": Superior thyroid Ascending laryngeal Lingual Occipital (O before F is an extremely common variation) Facial Posterior auricular Maxillary Transverse facial Superficial temporal
> External carotid artery branches
"She Lay Flaccid As Olaf's Penis Slipped In": · From caudal to cephalad: Superior thyroid Lingual Facial Ascending pharyngeal Occipital Posterior auricular Superficial temporal (Internal) maxillary
> Femoral artery deep branches
"Put My Leg Down Please": Profundus femoris (deep femoral artery) Medial circumflex femoral artery Lateral circumflex femoral artery Descending genicular arteries Perforating arteries
Hypertension: primary hypertension causes
Here Dictates Obtuse Asking DeMi Serious Sensation
Heredity, Diet, Obesity, Age, Diabetes mellitus, and stress, smoking increase blood pressure
Hypotension
low blood pressure
90/60mm Hg
What are blood vessels?
Delivery system of dynamic structures that begin and ends at the heart, arteries, capillaries, and veins
Lumen
central blood-containing space
3 layers in arteries and veins
Tunica intima
tunica media
tunica externa/ adventitia
Capilliaries
Endothelium w/ sparse basal lamina
Sparse basal lamina
thin connective tissue that holds these cell together
Tunica intima
endothelium lines lumen of all vessels and valves and chambers
where cardiovascular disease begins (inflamation)
continuous with endocardium, slick surface reduces friction
Subendothelial layer
in vessels larger than 1mm; connective tissue basement membrane
Tunica media
smooth muscle and sheets of elastin
How do tunica media work?
sympathetic vasomotor nerve fibers ctrl vasoconstriction/dilation (influence blood flow and pressure by alpha 1 receptors)
Tunica externa/adventitia
collagen fibers protect and reinforce
anchor to surrounding structures, has nerve fibers and lymph vessels
What is the vasa vasorum?
larger vessels nourishes external layer
How do blood vessels vary in ?
length, diameter, wall thickness, and makeup
Elastic Arteries
Large thick-walled arteries with elastin in all 3 tunics near the heart aka conducting arteries
What arteries are the largest in diameter?
elastic arteries
example of elastic artery
aorta and its major branches
Large lumens offers . . . . . .
low-resistance
What is inactive in vasoconstriction?
elastic arteries
What act as a pressure reservoirs? How?
elastic arteries expand and recoil as blood is ejected from the heart
How is the is pressure in the elastic arteries perceived?
smooth pressure downstream
Muscular arteries location
distal to elastic arteries
Role/Function of Muscular arteries
deliver blood to body organs
What tunica has the thickest muscular arteries???
Thick tunica media w/ more smooth muscle, thicker in artery
What artery is active in vasoconstriction and BP ?
Muscular artery
What is influenced by Alpha I receptors and what does this cause?
muscular arteries cause sympathetic stimulation yielding vasoconstriction or dilation
Arterioles
smallest arteries
what do arterioles lead to ?
capillary beds
function/role of arterioles
control flow into cap beds via vasodilation and vasoconstricition
What kind vessels do we identify arterioles as ?
resistance vessels
What do arterioles do to BP?
lowers it before pressure of blood enters caps like a regulator
What do arterioles have that make them affective?
branch and have greater surface area to reduce that BP
Capilliaries size
microscopic blood vessels
VEGF hormone
Vascular endothelial growth factor
What are capillaries made up of ?
walls of thin tunica intima, in smallest ones cells form entire circumference
Pericytes
help stabilize their walls and control permeability (anchoring network)
What do diameter of caps allow?
only a single Red Blood Cell to pass at a time (single file RBC)
What kind of cells do caps have? How come?
endothelial cells allow RBC to go through lumen
What do caps act similar to ?
act as paracrine (locally) hormone
What do caps do ?
slow blood down and dissociate co2 to o2
Where are capillaries?
In all tissues except for cartilage, epithelia, cornea and lens of eye
What do caps provide?
direct access to almost every cell besides the avascular and innervated ones
Functions of caps
exchange gases, nutrients, waste, hormones , etc .. . between blood and interstitial fluid
What are the three types of caps?
continuous
fenestrated
sinusoid
Where are continuous capillaries found?
abundant in skin and muscles
What are continuous caps?
Tight junctions connect btw endothelial cells with INTERcellular clefts allow passage of fluids and small solutes (Na+, k+ … ), and they not excessively permeable.
Where are continuous caps unique ?
the brain
Why are the continuous caps unique in the brain?
tight junctions are complete, form blood-brain barrier
vesicles carry fluids across endothelial lining
only fat-soluble blood brain barrier
What fenestrations?
Pores
What are fenestrated capillaries?
Some endothelial cells contain pores (fenestrations)
What are fenestrated caps more permeable than?
Fenestrated caps are more permeable than continuous caps
Function of fenestrated caps
absorption and filtradte formation (small intestines, endocrine glands, and kidneys)
still have tight junctions
Fenestrated caps in small intestines f(x)
absorbs nutrients from digested food
Endocrine glands fenestrated caps f(x)
allows rapid hormone entry into the blood
Kidneys fenestrated caps f(x)
rapid filtration of blood plasma
Sinusoids caps
fewer tight junctions usuaully fenestrated; larger intercellular clefts; large lumens, leaky caps
How does blood flow in sinusoids caps?
blood flows sluggishly that allows modification
so large molecules and blood cells pass btw blood and surrounding tissues
Where are sinusoids caps found?
only liver, bone marrow, spleen, and adrenal medulla
stellate macrophages role in sinusoid caps?
in lining to destroy bacteria
how does blood flow ?
slowly
What is the circulation in capillary beds called?
Microcirculation
What are cap beds?
interwoven networks of capillaries btwn arterioles and venules
direction of blood in cap beds
terminal arteriole to metarteriole
metarteriole
continuous with thoroughfare channel (intermediate between capillary and venule)
thoroughfare channel goes to
postcapillary venue that drains bed (pisses bed)
Cap beds two types of vessels
vascular shunt and true capillaries
Vascular shunt
type of cap bed
merarteriole to thoroughfare channel
function of vascular shunt
directly connects terminal arteriole and post capillary venule
True caps
10 to 100 exchange vessels / cap bed
true caps location
branch off met arteriole or terminal arteriole
sympathetic ANS causes shunts to
close during exercise
how does blood flow through true caps?
normally branch from metartiole and return to thoroughfare channel
Function of precapillary sphincters
regulate blood flow into true caps
blood may go into true caps or to shunt
what is blood flow in cap beds regulated by?
local chemical conditions and vasomotor nerves
for example, NO(g) acts like paracrine
Venues are formed when
capillary beds unite
What are venules?
smallest postcapillary venules
very porous; allow fluids and WBCs into tissue
consist of endothelium and a few pericytes
stabilize vessel
What do larger venues have?
one or two layers of smooth muscle cells
Veins formed when
venules converge
What make up veins ?
thinner walls, larger lumens compared with corresponding arteries
Does a vein or artery have lower blood pressure?
veins have lower bp than arteries
What tunic do veins or arteries have thick or thin of?
thin tunica media
thick tunica extern of collagen fibers and elastic networks
what are veins also called?
capacitance vessels (blood reservoirs) so less R and Pressure
Why are veins called Capacitance Vessels?
contain up to 65% of blood supply so they have less resistance and pressure
what do the adaptations in veins do?
ensure return of blood to heart despite low pressure
Why do veins have large diameter lumens?
offer little Resistance
Purpose of venous valves and where are they abundant
prevent back flow of blood (prevents incompetent valve peripheral edema) and abundant in veins of limbs
Venous sinuses
flattened veins with extremely thin wall
examples of venous sinuses
coronary sinus of heart and dural sinuses of brain
vascular anastomoses
interconnections of blood vessels, arteries suppling the same local region often merge together
What do arterial anastomoses provide?
alternate paths (collateral channels) to given body region
where are arterial anastomoses common?
at joints, in abdominals organs, brain, and heart
Where do not arterial anastomoses exist?
none in retina, kidneys, and spleen
What are examples of arteriovenous anastomoses?
vascular shunts of capillaries
What anastomoses are common?
venous anastomoses
how do most organs receive blood?
more than one arterial branch/supply, and have multiple back up
Blood flow is what?
volume of blood flowing through vessel, organ, or entire circulation in given period
How is blood flow measured?
ml/min
what is blood flow equivalent to and when?
CO for entire vascular system
When is blood flow relatively constant?
When at rest
healthy varies constant
how does blood flow and organs relate?
varies widely through individual organs based on needs such as exercise
BP Blood Pressure
Force per unit area exerted on wall of blood vessel by blood
What is BP expressed in?
mm Hg
What is BP measured as ?
systemic arterial BP in large arteries near heart
Pressure gradient provides what for BP?
driving force that keeps blood moving from higher to lower pressure areas
Resistance (peripheral R)
opposition to blood flow
Peripheral R is measure of what?
amount of friction blood encounters with vessel walls, generally in peripheral (systemic) circulation
What are the three important sources of R?
Blood viscosity
total blood vessel length
Blood Vessel DIAMETER
What has greatest influence on R?
blood vessel diameter because it has frequent changes that alter R (vasoconstriction and vasodilation)
How does R vary?
R varies inversely with fourth power of vessel radius (1/x^4)
What are major determinants of peripheral resistance?
Small-diameter arterioles
What can dramatically increase resistance?
ABRUPT changes in diameter or flatty plaques from atherosclerosis
What does increase in resistance do to flow?
disrupts laminar flow and cause turbulent flow
What does a disrupted laminar flow and cause turbulent flow mean?
irregular fluid motion makes increased resistance
How are blood flow and blood pressure gradient related?
Blood flow is directly proportional to blood pressure gradient so if pressure increases then blood flow speeds up
How does blood flow relate to peripheral resistance?
Blood flow is inverserly proportional to peripheral resistance (R), so if R increases, blood flow will decrease
What is more important in influencing local blood flow?
R more important in influencing local blood flow cuz easily changed by altering blood vessel diameter
What is systemic blood pressure?
pumping action of heart that generates blood flow?
What generates blood flow?
Systemic blood pressure, the pumping action of the heart
What does systemic blood pressure result from?
when flow is opposed by resistance
Systemic pressure
get answer in class
Where does the steepest drop in systemic blood pressure occur??
arterioles
Where is systemic blood pressure the highest and how come?
Aorta because it pushes the blood throughout the body with the most R
Systolic Pressure
pressure exerted in aorta during ventricular contration
What is the average systolic pressure in a normal adult human ?
120 mm Hg
Diastolic Pressure
lowest level of aortic pressure
Pulse Pressure
difference between systolic and diastolic pressure
Pulse by def
throbbing of arteries
Where can a pulse be felt?
Artery touching a firm tissue
Mean Arterial pressure (MAP)
pressure that propels blood to tissues
MAP equation
diastolic pressure + 1/3 (pulse pressure)
What 2 genres of pressure both decline with increasing distance from the heart?
MAP and Pulse Pressure
MAP and Pulse Pressure decline when?
with increasing distance from the heart
more distal less pressure
Capillary Blood Pressure range
17 to 35 mm Hg
How much pressure is desirable in cap pressure?
low cap bp
What type of pressure changes a little during cardiac cycle?
Venous blood pressure
What is the pressure gradient like in Venous Blood Presure and how much about?
small pressure gradient; about 15 mm Hg
Why low venous pressure?
cumulative effects of peripheral resistance
What happens to energy in low venous pressure?
Energy of BP lost as heat during each circuit
Muscular Pump
Contraction of skeletal muscles “milk” blood toward heart; valves prevent backflow
Respiratory Pump
pressure changes during breathing move blood toward heart by squeezing abdominal VEINS as thoracic VEINS expand
Venoconstriciton
under sympathetic control pushes blood toward heart
Maintaining Blood Pressure requires
Cooperation of heart, blood vessels, and kidneys. Also, the supervision of the brain.
What are the main factors influencing blood pressure?
CO Cardiac output, PR peripheral resistance, and blood volume
Blood pressure eqn
CO x PR
What does CO depend on ?
blood volume
Blood pressure relation with CO, PR, and blood volume?
Blood pressure varies directly with CO, PR, and blood volume
What happens if one variable changes in the maintenance of BP?
Changes in one variable quickly compensated for by changes in other variables
CO during stress what happens?
During stress, cardioacceleratory center increases HR and SV via sympathetic stimulation
CO and stress what happens to ESV and MAP?
ESV decreases and MAP increases
blood out of ventricles and blood propel
What controls blood pressure ?
Short-term neural and hormonal controls, and long-term renal regulation
Short-term neural and hormonal controls
counteract fluctuations in BP by altering PR and CO
Long-term renal regulation
counteracts fluctuations in BP by altering blood volume
Short-term mech: Neural ctrl work how?
Neural ctrls operate via reflex arcs
Reflect arcs in neural ctrls involve what 4 things?
Baroreceptors
Cardiovascular center of medulla
Vasomotor fibers to heart and vascular smooth muscle.
Sometimes input from chemoreceptors and higher brain centers.
What are in the cardiovascular center?
Clusters of sympathetic neurons in medulla oversee changes in CO and blood vessel diameter
What does the cardiovascular centers consist of ?
Cardiac centers and vasomotor center
Vasomotor tone
moderate constriction
Where does the cardiovascular center receive inputs?
Cardiovascular center receives inputs from baroreceptors, chemoreceptors, and higher brain centers
What does the vasomotor center send?
Vasomotor center sends steady impulses via sympathetic efferents (vasomotor fibers, efferents=away from center) to blood vessels –> moderate constriction called vasomotor tone
Where are baroreceptors reflexes located?
carotid sinus, aortic arch, and Arteries of neck and thorax
Barorecptors and chemoreceptors reflexes are long or short term mechanisms?
short term mech
What does increases BP do in short-term mechanisms?
Increased blood pressure stimulates baroreceptors to increase input to vasomotor center
What does a increased BP stimulation of baroreceptors to increase input to vasomotor center cause?
Inhibits vasomotor and cardioacceleratory centers causing arteriole dilation and venodilation.
Stimulates cardioinhibitory center –> decreased BP
In short-term mech: baroreceptor reflexes, what happens if MAP is low?
Reflex vasocontriction -> increased CO –> increased BP
What an example of if MAP is low in short term mech?
Upon standing baroreceptors of carotid sinus reflex protect blood to brain; in systemic circuit as whole aortic reflex maintains BP
When are baroreceptors ineffective?
if altered blood pressure sustained
Where are chemoreceptors and what do they detect?
Chemoreceptors in aortic arch and large arteries of neck detect increase in co2 or drop in pH or o2
What do chemorecptors causes?
increased blood pressure
How do chemoreceptors cause an increase BP? 2 ways
1) Signaling cardioacceleratory center to increase BP.
2) Signaling vasomotor center to increase BP.
What influences higher brain centers?
Reflexes in medulla, hypothalumus cerebral cortex
How does hypothalamus and cerebral cortex influence higher brain centers?
They modify arterial pressure via relays to medulla
What does hypothalamus do to BP during stress?
increases BP
What does the hypothalamus mediates?
redistribution of blood flow during exercise and changes in body temperature
How does short term regulation (Hormonal ctrl) regulate?
via changes in PR
Long term regulation in hormonal ctrl via?
changes in Blood volume
Short term mech hormonal ctrl cause?
increased and lower BP
How does hormonal ctrl in short term mech cause increased BP?
Epinephrine and norepinephrine from adrenal gland causes and increased CO and vasoconstriction.
Angiotensin II stimulates vasoconstriction.
High ADH levels cause vasoconstriction.
How does hormonal ctrl in short term mech caused lower BP?
ANP causes decreased blood volume by antagonizing aldosterone.
In long term mech:Renal Reg, how to do baroreceptors adapt ?
Baroreceptors quickly adapt to chronic high or low BP so are ineffective
What do long-term renal reg mech ctrl?
BP by altering blood volume via kidneys
What regulates arterial blood pressure and how?
Kidneys regulate arterial blood pressure
What are the two mechanism that kidneys use to regulate arterial blood pressure?
direct renal mech and indirect renal mech (renin-angiotensin-aldosterone mechanism)
Direct Renal Mechanism
Alters blood volume independently of hormones
How does direct renal mech work?
Increased BP or blood volume causes elimination of more urine, thus reducing BP
Decreased BP or BV causes kidneys to conserve water and BP rises
Through either retention or excretion of sodium
Indirect renal Mech is the
renin-angiotensin-aldosterone mech
How does indirect renal mech?
Renin-angiotensin-aldosterone mech
Decreased arterial blood pressure causes the release of renin, Renin then catalyzes conversion of angiotensinogen from liver to angiotensin I, and then (ACE) angiotensin converting enzyme, especially from lungs and all vascular endothelium, converts angiotensin I to angiotensin II.
2 Functions of Angiotensin II
Increases Blood volume and causes vasoconstriction directly increasing BP
How does Angiotensin II increase blood volume?
Stimulates aldosterone secretion, causes ADH release, and triggers hypothalamic thirst center
What vital signs?
pulse, BP, Respiratory Rate, and body temperature
Pulse
pressure wave caused by expansion and recoil of arteries
Radial Pulse
taken at wrist, routinely used
Pressure Points
where arteries close to body surface, and can be compressed to stop blood flow
Where is systemic pressure the highest?
aorta
What pressure declines throughout the pathway?
systemic pressure
What is systemic pressure in the right atrium?
0 mm Hg
Why is MAP 1/3 pulse pressure at rest?
Because cardiac cycle has systolic and diastolic pressure. At rest, systolic is 1/3 of the pulse pressure, and while exercising, 50-60% of the pulse pressure.
Systolic Pressure normally less than?
120 mm Hg
What is the pressure when sounds first occur as blood starts spurts through the artery?
systolic pressure
Diastolic Pressure normally less than?
80 mm Hg
Sounds for diastolic pressure?
when sounds disappear cuz artery no longer constricted; blood is free flowing.
Can you have systolic pressure and diastolic at same time?
Yes
Hypertension
High blood pressure
What is the bp for hypertension?
140/90 or higher
What is prehypertension?
if values of BP are elevated but not yet in hypertension range
Where is prehypertension often persistent?
in obese ppl
When are their transient adaptions from prehypertension?
during fever, physical exertion, and emotional upset
What does prolonged hypertension is major cause of what?
heart failure, vascular disease, renal failure, and stroke
Why is hypertension bad for heart?
heart must work harder so the myocardium enlarges then gets weaker and becomes flabby
What does hypertension accelerate?
Atherosclerosis
Preload and after load is increased causing heart damage
thrombosis
mass of platelets in blood that when they open blocks the blood in vessel under the endothelial wall
hypotension
low blood pressure
what is hypotension for measure?
90/60 mm Hg
When is hypotension a concern?
only when it leads to inadequate blood flow to tissues
What is hypotension often associated with?
long life and lack of cardiovascular illness
Orthostatic hypotension
temporary low BP and dizziness when suddenly rising from sitting or reclining position
Chronic hypotension
hint of poor nutrition and warning sign for Addison’s disease or hypothyroidism
Acute hypotension
vital sign of circulatory shock; threat of surgical patients and those patients in ICU
Autoregulation
automatic adjustment of blood flow to each tissue to relative to its varying requirements
How is autoreg controlled?
controlled instrically by modifying diameter of local arterioles feeding capillaries
What autoreg independent of ?
MAP, which is ctrlled as needed to maintain constant pressure
How do organs regulate own blood flow?
Organs varying resistance of own arterioles
Metabolic Ctrls
vasodilation of arterioles and (NO gas) relaxation of recap sphincters occur in response to
vasodilation of arterioles and relaxation of recap sphincters occur in response to
declining tissue o2 and substances from metabolically active tissue (H+, K+, adenosine, and prostaglandins and inflammatory chemicals
Prostaglandins
inflammation
Metabolic ctrls effects
relax of vascular smooth muscle release NO(g), a powerful vasodilator by endothelial cells
Endothelins in metabolic ctrls
released from endothelium are potent vasoconstrictors
When are NO and endothelia’s not balanced
blood flow is inadequate and NO wins
What can in metabolic ctrls vasodilation?
inflammatory chemicals
Myogenic response do what?
keep tissue of perfusion constant despite most fluctuations despite most fluctuations in systemic pressure
What responds to stretch?
Vascular smooth muscle responds to stretch
Passive stretch
increased intravascular pressure
Passive stretch promotes what?
increased tone and vasoconstriction
Reduced stretch promotes
vasodilation and increased blood flow to tissue
When does long term autoreg happen?
when short-term auto regulation cannot meet tissue nutrient requirements
Angiogenesis
Number of vessels to region increases and existing vessels enlarge
Where angiogenesis common?
in heart when coronary vessel occluded or throughout body in ppl in high-altitude areas`
How does blood flow in skill muscles?
varies with fiber type and activity
What kind of people get angiogenesis commonly?
Occurs in ppl who frequently exercise cuz increase in demand
At rest what is predominate and maintains 1L/min
myogenic
general neural mechanisms
During muscle activity what ctrl to blood flow?
Active or exs hyperemia
Local ctrls override sympthateic vasoconstriction
Muscle blood flow can increase 10x
Active or exs hyperemia
blood flow increases in direct proportion to metabolic activity
Blood flow to brain is . . . ?
constant as neurons intolerant of ischemia; averages 750ml/min
Blood flow to brain metabolic ctrls work how?
Decreased pH of increased co2 cause vasodilation
Myogenic ctrls blood to brain how?
Decreased MAP causes cerebral vessels to dilate
Increased MAP causes cerebral vessels to constrict
MAP below 60 mm Hg can cause what?
syncope
MAP above 160 mm Hg results in?
cerebral edema
Blood flow through skin how?
supplies nutrients to cells (outrage in response to o2 need)
What does bf through skin help regulate?
body temp (neurally crtrlled and is primary f(x)
What does BF in skin provides ?
blood reservoir (neurally ctrlled)
How does BF to skin reg body temp?
BF to venous plexuses below skin surface regulates body temp
What BF to skin controleld by?
sympathetic nervous system reflexes initiated by temp receptors and central nervous system
How does body temp rise?
heat exposure
fever
vigorus exs
Temp reg
Hypothalamic signals reduce vasomotor stimulation of skin vessels, then warm blood flushes into cap beds, and then heat radiates from skin
What causes vasodilation in temp reg?
Sweat via bradykinin in perspiration
Bradykinin stimulates what?
NO release
What happens to blood as temp decreases?
blood is shunted to deeper more vital organs
Cap exchange of respriatory gases and nutrients diffusion how does it work?
Diffusion down concentration gradients by o2 and nutrients from blood to tissues and co2 and metabolic wastes from tissue to blood
How do lipid-soluble molecules diffuse?
directly through endothelial membranes
How do water soluble molecules diffuse?
pass through clefts and fenestrations
How do large molecules such as proteins pass through?
actively transported in pinocytotic vesicles or carveolae
Circulatory shock
Blood vessels inadq filled, blood cannot circulate normally, and results in inadq BF to meet tissue needs
3 types of circulatory shock
hypovolemic, vascular, and cardiogenic shock
hypovolemic shock
results from large-scale blood loss
Vascular shock
results from extreme vasodilation and decreased peripheral R
cardiogenic shock
when an inefficient heart cannot sustain adq ciruclation
Renal Artery supplies
kidney
Renal artery does do this
does not anatmose
largest artery in the body
aorta
Internal iliac artery supplies
supplies pelvic structure
External iliac artery supplies
a lower limb
common site to take pulse
radial artery
Major supply to the cerebral hemispheres
internal carotid artery
subclavian vein drains
upper extremities, deep vein
Runs through armpit area, giving off branches to axillae, chest wall, and shoulder girdle
axillary artery
receives blood from all areas superior to the diaphragm, except the heart wall
superior vena cava
carries oxygen-poor blood to lungs
pulm trunk
drains scalp
external jugular vein
artery usually ausculated to take the blood pressure
brachial artery
Major artery of the thigh
femoral artery
carries oxygen-rich blood from lungs
pulm vein
Site where R to bf is greatest
arterioles
site where exchanges of food and gases are made
capillaries
site where bp is lowest
large veins
site where the velocity of bf is fastest
large arteries
site where blood volume is the greatest
large veins
site where bp is greatest
large arteries
site that is the major determinant of PR
arterioles
Which statement best describes arteries?
All carry blood away from the heart
artery
away from heart
Permitting the exchange of nutrients and gases btw blood and tissue cells is the primary function of what?
capillaries
Pulse pressure is
systolic pressure minus diastolic pressure
during vigorous exs?
caps of the active muscle will be engorged with blood
Why are arterioles known as resistance vessels?
the contraction and relaxation of smooth muscle in their walls can change their diameter
Veins are known as what ?
capacitance vessels or blood reservoirs
What tunic of an artery is most responsible for maintaining BP and continuous blood circulation?
tunica media
The influence of blood vessel diameter on PR is what?
significant cuz R is inversely proportional to the fourth power of the vessel radius
Which of the following is the most significant source of blood flow resistance?
blood vessel diameter
Which of the following are involved directly in pulm circulation?
right ventricle, pull artery, and left atrium
The arteries that directly feed into the cap beds are called
arterioles
factors that aid venous return
venous valves (venoconstriction)
skel muscle pump
resp pump
What factor does aid venous return?
urinary output
