Quantcast
Merriam-Webster Logo
  • Dictionary
  • Thesaurus
  • Medical
  • Scrabble
  • Spanish Central
  • Learner's Dictionary

Medical Dictionary

sinoatrial node

noun

Medical Definition of sinoatrial node

  1. :  a small mass of tissue that is made up of Purkinje fibers, ganglion cells, and nerve fibers, that is embedded in the musculature of the right atrium of higher vertebrates, and that originates the impulses stimulating the heartbeat—called also S-A node, sinus node




Learn More about sinoatrial node


Seen and Heard

What made you want to look up sinoatrial node? Please tell us where you read or heard it (including the quote, if possible).

WORD OF THE DAY

February 7, 2016

a slight offense

Get Word of the Day daily email!

WORD GAMES

Take a 3-minute break and test your skills!

image1037863653

Which of the following refers to thin, bending ice, or to the act of running over such ice?

pince-nez kittly-benders spindrift duvet
Name That Thing

10 quick questions: hear them, spell them, and see how your skills compare to the crowd.

TAKE THE QUIZ
SCRABBLE® Sprint

Test Your Knowledge - and learn some interesting things along the way.

TAKE THE QUIZ