blood pressure

  • oxgenated blood from lungs to systemic circulation

  • de-exgyenated blood pump back into lungs

  • hydrostatic pressure- force of liquid against wall of container

  • blood pressure- force on walls of blood vessel by blood


  • systolic pressure- max pressure in vessels during contraction of ventricles

  • diastolic pressure- pressure on ventricles at rest

  • blood pressure- cardiac output x peripheral resistance

  • cardiac output- volume of blood pumped by left ventricle into aorta per minute.

  • peripheral resistance- measurment that blood flows through vessel.


how is blood pressure controlled?-

sympathetic nervous system:

  • stimulation of SNS through vasoconstriction and vasodialation

  • bararoceptors (pressure receptors):

  • aortic arch, internal carotid, large vessels in neck

  • stimulate by stretch of artery wall

  • if BP rise artery wall stretched and barorceptors send impulse to vasomotor center (in brain) to lower heart rate.

kidneys:

  • control water loss from urine

  • high blood pressure causes blood vessels to narrow and aldosterone is released which helps kidneys retain salt and water.

chemoreceptors:

  • found in aortic arch and carotid artery

  • response to low levels of CO2

  • severe hypoxia produce sympathetic stimulation and inc heart rate and BP

normal BP- 100/60mmHg - 140/90mmHg

normal pulse- 60-100 bpm(adult) 110-160 bpm(neonate)

sounds to hear while taking BP:

  • clear tapping- systolic reading

  • sound less clear- mumur

  • clear sound return

  • muffling of sound

  • sound disappear- diastolic reading

factors affecting BP:

  • accuracy of equipment

  • cuff size (too small/ too big)

  • position of woman

  • emotional state

sites for taking pulse:

temperature control:

  • heat loss from air temp

  • heat from 1 surface to other

  • touching cold surface

  • heat gained from- metabolic rate/ physical activity/ extreme external environment