Blood Vessels & Circulation

Front 1

Blood Pressure

Back 1

-force of blood against vessel walls
-usually measured in brachial artery of arm

Front 2

systolic

Back 2

ventricles contract

Front 3

diastolic

Back 3

ventricles relax

Front 4

average healthy Blood Pressure

Back 4

120/70

Front 5

hypertension

Back 5

high BP

Front 6

local control

Back 6

achieved thru several methods of autoregulation

ability of a tissue to regulate its own blood flow

Front 7

homeostatic equilibrium

Back 7

decreased blood to tissue  hypoxia, waste accumulation  stimulates vasodilation  increases blood to tissue  increases oxygen, decreases wastes  vessels constrict

Front 8

vasoactive chemicals

Back 8

chemicals that stimulate blood vessel movement (dilation or constriction)

during trauma, inflammation, exercise:

release of histamine, bradykinin, prostaglandins
these cause vasodilation

cells lining blood vessels (endothelial cells)
can release vasodilators & vasoconstrictors

Front 9

reactive hyperemia

Back 9

-greater than normal blood flow to a tissue
-can occur after blood flow is cut off, then restored
-seen after removing blood pressure cuff, coming in from cold

Front 10

angiogenesis

Back 10

growth of new blood vessels
seen in athletes: grow more vessels in muscles
can occur in coronary circ. around a blockage
occurs monthly in uterine lining
controlled by several substances that can promote and inhibit vessel growth
in some cancerous tumors, increases vessel growth to tumor

Front 11

neural control

Back 11

vasomotor center of medulla oblongata
-controls 3 autonomic reflexes:

baroreflex chemoreflex medullary ischemic reflex

Front 12

baroreflex

Back 12

-control short-term BP, as in changing posture
-uses baroreceptors, mainly in aorta & carotid arteries
-stretch receptors that respond to pressure changes

Front 13

baroreflex pathway

Back 13

BP rises  detected by baroreceptors  signal to medulla  inhibits sympathetic neuron signals  HR decreased, cardiac output decreased, vasodilation  BP decreases

if BP decreases  increased sympathetic output from medulla  HR, etc. increased, vasoconstriction  BP increases

Front 14

chemoreflex

Back 14

-responds to changes in blood chemistry (pH, O2, CO2)
-detected by chemoreceptors in organs called aortic bodies and carotid bodies
-regulates both breathing rate and vasomotion

Front 15

vasomotion is affected like this:

Back 15

hypoxemia (low O2), hypercapnia (high CO2), or acidosis (low pH)  detected by chemoreceptors  medulla ↓ parasym. and ↑ symp. signals  ↑ HR, SV and vasoconstriction  increased BP  increased blood to lungs  increased gas exchange

Front 16

breathing rate is affected like this

Back 16

chemoreceptors detect problem  medulla & pons  breathing muscles  increased breathing rate & depth  increased gas exchange

Front 17

c) medullary ischemic reflex

Back 17

the medulla monitors its own blood supply

Front 18

medullary ischemic reflex blood supply pathway

Back 18

lowered blood flow to brain  response by medulla cardiac and vasomotor centers  send sympathetic signals to heart and blood vessels 
-increase heart rate & force of contraction
-increase vasoconstriction 
increase BP  increase blood to brain