04 06 2015 Exam 11 Capillaries Smallest RBC Very thin walls only 1 cell o B c diffusion has a distance problem Site exchange D o Higher surface area o Lower flow rate Lowered hydrostatic Pressure Venules return to the heart Thin walled o Not bc the same reason of the o Bc there is not enough force o Further from the heart so bp is lower Lowered hydrostatic pressue o Less surface area Veins Bigger returning Lower hydrostatic pressure o Bc is the furthest away from the heart Skeletal muscle present Flow is still based on the actions of the heart o Decerasing bp bc were getting further from source of pressure but still based on the heart o Like trying to go against a crowd o Harder for the heart to ge the blood back to us when we send it down so far bc we have an issue with gravity Coming back were going against gravity RICE so we can help the heart circulate blood flow to the foot when injured Flow still based on the heart o But aided by skeletal muscle o Cuspid valve or semi something valve o One way valves BLOOD ONLY GOES ONE WAY THROUGH THEM Blood Pressure Arterial Blood Pressure o The pressure that the Dr measures with the cuff o Determined by 1 Volume of blood PV nRT Volume of blood is actually n Size of the vessel is V 2 Wall s rigidity If walls are elastic the blood pressure goes down bc energy is spent pushing against walls instead of carrying blood through o In large vessels mirrors cardiac cycle Has diminished bc of elasticity of the walls Systolic P Squeeze Maximum pressure at the end of the contraction I fhte first number is too big the heart is squeezing a lot Top number Diastolic P Minimum pressure before the next contraction Volume is the smallest PV nRT o Smallest volume biggest pressure Bottom number Arteriolar Blood Pressure o Arterioles regulate flow to areas e g organs o When coming off of the heart we see all one pressure Shouldn t see a big pressure o When having arteorlar we can have all different pressures o Difference in flow by difference in diameter o Change flow going to a particular area in 3 basic ways Make adjustments 1 Local factors Via autocrines and paracrines Not going to be happening with things coming from a distant area Endocrines come from a long way so they will not be a local factor There will be times when an area will be doing a specific activity where it needs more blood flow Active hyperemia o An activity drawing blood to a particular area By working a particular muscle it tells the blood flow it needs more blood flow to its area o Increase flow through an area due to increase in metabolic activity An area itself increases its blood flow Stomach needs more blood flow to digest or absorb food o We don t wThe trachea always remains patent i e open because of the found in the tracheal wall ant to lose brain or heart function o Individual arteriole Changes in Flow autoregulation 2 Extrinsic control Parasympathetic has little impact Vasodilation increase flow Making the size of the vessel bigger Can flow more stuff through it Decrease in blood pressure Nitric oxide NO o Free radical o Epinephrine In skeletal muscle Vasoconstriction less flow Tighter space Higher blood pressure Vasopressin ADH retain water in the body Angiotensin II and constrict blood vessels maintains homeostasis by regulating water glucose and salts in blood causes vasoconstriction and increase of blood pressure also stimulates the release of aldosterone peptide hormone that o Comes from and impacts association with kidneys Norepinephrine o Activated with sympathetic o Sympathetic makes bp go up Epinephrine o Blood pressure goes up everywhere besides skeletal muscle 3 Endothelial cell secretions The cells in the making of the blood vessels that create separation between blood and the rest of the body The blood vessels themselves determining their size Paracrine effect on surrounding smooth muscle Only need to use a paracrine Need to constrict and dilate Is a different area doing the control Nitric oxide vasodilation Endothelin 1 ET 1 vasoconstriction Detecting Blood Pressure Baroreceptors o Receptors associated with blood vessels o Mechanoreceptors stretch receptors Stretch receptors in large arteries What is the heart doing that can be adjusted later on in the system o Where do we see them Carotid and aortic arch o Short term regulation o Afferent input to brainstem neurons Brainstem translates amount of input into a blood pressure idea If the blood pressure is outside of the proper range we are no longer in ss and bp is too high o High blood pressure Increase baroreceptors AP Increase Parasympathetic and decrease sympathetic decrease in blood pressure o Low blood pressure opposite Increase baroceptors AP Decrease parasympathetic and increase sympathetic increase blood pressure A big problem Everything does all it can to get blood pressure up so it can survive Adds second system Adds endocrine system Endocrines increase blood pressure Secretion of angiotensin II and vasopressin ADH Both vasoconstrictors that increase bp Do not want to add nitric oxide b c vasodilator which will continue to lower blood pressure by adding more space for blood to flow o Which is worse High consistent or low consistent blood pressure Low b c not getting sufficient nutrients Long term Regulation Based on blood volume o Influences venous Pressure o More blood comes back to heart o More venous return o Stroke volume and cardiac output o Higher blood volume higher blood pressure Changing N not V in pv nrt BV regulated by kidneys o If someone has too much blood volume we make them pee more reduces blood volume lowers blood pressure ADH VASOPRESSIN allows for reabsorption of water and excretion of wastes increased blood volume increased blood pressure higher blood pressure has vasoconstriction occuring o Lowers blood pressure o Excrete excess fluid 4 8 15 She wrote in green on the board today in class Long term Regulation Based on Blood Volume blood pressure tied to the blood volume o Influences venous P venous return SV and CO o Increase in blood volume results in an increase in blood pressure note changing n not V in PV nRT BV regulated by kidneys excrete excess fluid Other factors regulating o Increase in blood pressure due to a decrease in oxygen increase in CO2 skin pain These two things are tied to our cell metabolism process o When you are in a fight or flight situation your blood pressure increases skin pain flight response Anticipation that that pain will set you up for the fight or o
View Full Document
Unlocking...