Circulatory System: Blood Vessels
Arteries
Transport blood from the heartHIGH pressureCarry oxygen rich blood (except pulmonary artery)
3 tunics (layers):Tunicintima– friction reducing lining endotheliumTunic media – bulky middle layer muscle and elastic tissueTunicexterna– connective tissue
Veins
Transport blood back to the heartLOW pressureSame 3 layers except thinner wallsValves = blood flow in one direction
Capillaries
One thin layer of endotheliumPlay an exchange role with tissue cells for nutrients and wasteCapillary beds open and close to shunt blood from one body system to anotherPressure dropsLumen is the opening
Pulse
Pulse is the alternate expansion and recoil of a blood vessel wall as the heart beats; felt over any external superficial artery = pressure point
Blood Pressure
Blood pressure is the pressure that blood exerts on the walls of the blood vesselsForces blood to continue moving
Pressure is measured over a pressure point, both systolic and diastolic
Arterial blood pressure is influenced by heart rate (higher = higher) or resistance to blood flow: decrease in diameter, stretch of vessels, or viscosity of blood
Special Circulations
Hepatic Portal
The hepatic portal veins drain the digestive organs, spleen, pancreas, and deliver nutrient rich blood to the liver – which is involved in maintaining the proper glucose, fat, and protein concentrations.
Brain Circulation
A continuous blood supply is maintained by two pairs of arteries:The internal carotidsThe vertebral arteries
TheInternalCarotidseach divide and run into the anterior and middle cerebral arteriesVertebralseachdivideto form the posterior cerebral arteries
The anterior and posterior blood supply are connected by branches- forming a complete circle
The Circle of Willis
It protects the brain by supplying more than one route to reach all brain tissue
Fetal Circulation
A temporary circulation involving 3 vessels:One umbilical- nutrients andoxygen to the fetustwo umbilical arteries- carry carbon dioxide and waste to the placentaShunts bypass the lungs and the liver
Naming the systemicArteriesandVeins
Starting with the arteries we will move away from the heart (arteries move blood away)
Arteries above the diaphragm
All branch off the Aorta (largest artery)1stSMALL branch is thecoronary artery-which serves the heart1stLarge branch is theBrachiocephalic2ndLarge branch is theRight Common Carotid3rdLarge branch is theRightSubclavian
Off of the Brachiocephalic:
Left Common CarotidLeftSubclavian
Each of the Common Carotids branch into :
Internal Carotidwhich goes to the brainExternal Carotidwhich serves the head
Each of theSubclavianswill:
1stbranch will beVertebralwhich goes to the brainUnder the armpit thesubclavianbecomes theAxillaryWhich in the upper arm is theBrachialwhere blood pressure is normally takenThe Brachial will split into theUlnar(medial) and theRadial(lateral)
Arteries under the diaphragm
All branch off the Aorta (abdominal)1stbranch is theCeliac Trunkwith 3 branches:Gastric- to stomachHepatic- to liverSplenic- to spleenNext comes theSuperior Mesentericwhich serves the upper part of the intestine
Continuing down the abdominal aorta:
Right and LeftRenalbrings blood to the kidneysLumbarbrings blood to the back musclesGonadalbrings blood to the gonadsAt the end of the torso:Common Iliac Artery
The Common Iliac Artery splits:
External Iliacwhich becomes the Femoral in the thighInternal Iliacloops back towards the pelvisDeep Femoralgoes toward buttocksFemoralcontinues down thigh, will become thePoplitealbehind the kneeIt splits into theAnterior and PosteriorTibialEnds in the foot at theDorsalisPedis
The veins bring blood back to the heart so we start at the distal end and move towards the heart.
All the veins above the diaphragm drain into theSuperior Vena Cava
TheRadialandUlnarVeins from the forearm drain into theBrachialveinTheCephalic(lateral) andBasilic(medial) meet at theMedianCubital(place where you get blood drawn for blood tests!)They all drain into theBrachial vein
TheBrachialdrains into theAxillaryunder the armpitTheAxillarydrains into theSubclavianTheVertebraltakes blood from the posterior head and drains into theSubclaviansThe right and leftSubclaviansdrain into the right and leftBrachiocephalic
TheExternal Jugulardrains the head and theInternal Jugulardrains the brain: both empty into theBraciocephalicTheRight and LeftBraciocephalicjoin to form theSuperior Vena Cavawhich enters the heartTheAzygosis a single vein that runs up the spine, drains the entire thorax and enters the SVC just before the heart
All veins below the diaphragm drain into theInferior Vena Cava
TheAnterior and PosteriorTibial– drain the calf and foot then become thePoplitealat the kneeThePoplitealbecomes theFemoralat the thighTheGreat Saphenousvein is the longest vein, it drains the superficial veins of the leg and empties into theFemoral
TheFemoraldrains into theExternal IliacTheInternal Iliacdrains the pelvisTheExternal & InternalIliacsmeet at theCommon IliacTheRight and Left Common Iliacjoin to form theInferior Vena Cava
TheRenalveins drain the kidneysTheGonadalveins drain the gonadsTheHepaticVeins drain the liverThey all drain into theInferior Vena CavaREMEMBER ALL DIGESTIVE ORGANS (GASTRIC, INTESTINES) DRAIN INTO THEHEPATIC PORTALAND GO TO THE LIVER FOR PROCESSING, THEN ARE DRAINED BY THEHEPATIC VEIN!
The Inferior Vena Cava enters the heart, and it starts all over again.
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