In times of stress, activation of the sympathetic nervous system results in the adrenal gland secreting hormones that tend to:

Stressful conditions activated sympathetic nervous system which shows a fight and flight response by preparing adrenal glands to release specific hormones during stress. During fight and flight conditions, adrenal medulla releases certain hormones:

- Epinephrine or adrenaline

-Norepinephrine  

These two hormones releases from adrenal medulla during stressful conditions. They tend to spike up the heart rate and blood sugar level by breaking down more glycogen into glucose. They also increase the heart flow towards brain and muscles.  Norepinephrine also cause vasoconstriction which is the narrowing down of blood vessels results in high blood pressure.

cats appear to have glowing cat eyes because the back of their eyeballs includes a special reflective surface called the tapetum lucidum. this lets them see better during the night, giving them a much better vision.

several tissues working together form an organ, and several organs together make up an organisms.

the group of cell that carries out special jobs are tissue.