Adrenaline prepares the body

The idea

Adrenaline, secreted by the adrenal glands directly into the blood, prepares the body to deal with a scary situation: the heart beats faster, blood is diverted from the digestive system and skin to skeletal muscles, and breathing rate increases.

A scary moment

A squirrel gets a scare. Its body must get ready, in a moment, to fight or to run away. Both need a great deal of energy.

How could one signal prepare many parts of the body at the same time?

• A chemical in the blood that reaches different parts of the body
• A single nerve that touches every muscle
• The squirrel simply thinks about it

Fight or flight

Press Next step. This is a simple picture of a body.

Ready for either

Fighting and running are different, but both need the heart, the muscles and the lungs to work harder. One chemical in the blood can prepare them all.

Adrenaline, secreted by the adrenal glands directly into the blood, prepares the body to deal with a scary situation. The heart beats faster, blood is diverted from the digestive system and skin to the skeletal muscles, and the breathing rate increases.

Notes

Adrenaline, secreted by the adrenal glands directly into the blood, prepares the body for a scary situation: the heart beats faster, blood is diverted to the skeletal muscles and breathing rate increases.

Check yourself

Which glands secrete adrenaline?

Where is adrenaline secreted?

What does adrenaline do to the heart?

Where is blood diverted to?

• The thyroid gland. The thyroid gland makes thyroxin.
• The adrenal glands — correct. Yes!
• The pituitary. The pituitary secretes growth hormone, among other hormones.
• Into a synapse between two neurons. Adrenaline is a hormone. It is secreted directly into the blood and carried to different parts of the body.
• Into the digestive system only. Adrenaline is secreted directly into the blood.
• Directly into the blood — correct. Yes!
• Makes it beat faster — correct. Yes!
• Makes it beat slower. Adrenaline makes the heart beat faster, which supplies more oxygen to the muscles.
• Has no effect on it. The heart is one of the target organs. It beats faster.
• To the digestive system, from the skeletal muscles. This is the reverse. Blood to the digestive system and skin is reduced.
• To the skeletal muscles, from the digestive system and skin — correct. Yes!
• To the skin, from the heart. Blood to the skin is reduced, and the heart beats faster.