While norepinephrine is majorly a neurotransmitter (in synaptic transmission)
, it also acts as a hormone produced by
the adrenal gland. It is usually secreted as a stress hormone, just like
cortisol. It increases heart rate, blood flow
in skeletal muscles, production of glucose by the liver, especially in the
fight-or-flight response.
That's true cause it is not good for the ocean animals..
I believe it's the precise control of the retention of <span>water and electrolyte.</span>
Answer:
in the wall of the right atrium of the heart.
Explanation:
The sinoatrial node (SA), consisting of spindle-shaped cells, initiates the electrical activity of the heart. From its location in the right atrium in proximity to the superior vena cava, the electrical activity spreads to the atria, whose cells are larger than those of the SA.