blood vessels arteries: vessels that carry blood away from heart, surrounded by thick layer of...
TRANSCRIPT
Blood VesselsBlood Vessels
Arteries: vessels that carry blood away from Arteries: vessels that carry blood away from heart, surrounded by thick layer of smooth heart, surrounded by thick layer of smooth muscle, high levels of BPmuscle, high levels of BP
Capillaries: microscopic thin walled vessels Capillaries: microscopic thin walled vessels connect to the smallest veins and arteriesconnect to the smallest veins and arteries
Veins: vessels that carry blood to heart Veins: vessels that carry blood to heart surrounded by thin layer of smooth muscle and surrounded by thin layer of smooth muscle and are flaccid, low levels of BP are flaccid, low levels of BP
Vessel Wall LayersVessel Wall Layers
Tunica interna: inner of vessel, direct contact Tunica interna: inner of vessel, direct contact with blood, secretes chemicals for dilation and with blood, secretes chemicals for dilation and constriction of the vesselconstriction of the vessel
Tunica media: middle layer, made of smooth Tunica media: middle layer, made of smooth muscle and elastic fibers to prevent rupture muscle and elastic fibers to prevent rupture from BP and to aid in vasomotionfrom BP and to aid in vasomotion
Tunica externa: covers vessel and anchors it to Tunica externa: covers vessel and anchors it to tissue and other vesselstissue and other vessels
ArteriesArteries
Conducting arteries: biggest in the body i.e. Conducting arteries: biggest in the body i.e. aorta, carotid. Large amounts of elastic fibers aorta, carotid. Large amounts of elastic fibers allow expansion and contraction with each HB allow expansion and contraction with each HB normalizing BPnormalizing BP
Distributing arteries: smaller branches that Distributing arteries: smaller branches that deliver blood to specific organsdeliver blood to specific organs
Resistance arteries: very little elastic fiber, Resistance arteries: very little elastic fiber, funnel blood to capillaries, smallest called funnel blood to capillaries, smallest called arteriolesarterioles
VeinsVeins
Postcapillary venules: smallest veins, Postcapillary venules: smallest veins, more porous than capillaries allowing more porous than capillaries allowing fluid exchange fluid exchange
Muscular venules: have a thin layer of Muscular venules: have a thin layer of smooth musclesmooth muscle
Medium veins: have venous valves Medium veins: have venous valves acting in the skeletal muscle pump that acting in the skeletal muscle pump that resists retrograde flow caused by gravity resists retrograde flow caused by gravity
VeinsVeins
Venous sinuses: large thin walled Venous sinuses: large thin walled vessels found in the heart and brain not vessels found in the heart and brain not capable of vasomotioncapable of vasomotion
Large veins: thin tunica media with thick Large veins: thin tunica media with thick tunica externa made of bundles of tunica externa made of bundles of smooth muscle, (venae cavae, smooth muscle, (venae cavae, pulmonary veins)pulmonary veins)
Blood PressureBlood Pressure
Flow: amount of blood flowing in an Flow: amount of blood flowing in an organ, tissue or vessel in a given timeorgan, tissue or vessel in a given time
Perfusion: volume of blood over time per Perfusion: volume of blood over time per gram of tissuegram of tissue
Blood pressure: the pressure exerted on Blood pressure: the pressure exerted on the wall of a vessel (120/80)the wall of a vessel (120/80)
Pulse pressure: the difference between Pulse pressure: the difference between systolic and diastolic pressuressystolic and diastolic pressures
Blood PressureBlood Pressure
Hypertension: chronic high BP of 140/90 Hypertension: chronic high BP of 140/90 or higher or higher
Hypotension: chronic low BP can be Hypotension: chronic low BP can be caused by blood loss, dehydration, caused by blood loss, dehydration, anemiaanemia
ResistanceResistance
Blood viscosity: the thickness of blood can Blood viscosity: the thickness of blood can increase or decrease blood flowincrease or decrease blood flow
Vessel length: friction develops with length Vessel length: friction develops with length Vasoconstriction: narrowing vessel Vasoconstriction: narrowing vessel ↑↑ BP BP Vasodilation: widening of vessel Vasodilation: widening of vessel ↓↓ BP BP Laminar flow: blood in center of vessel Laminar flow: blood in center of vessel
travels faster than blood along vessel walltravels faster than blood along vessel wall