Coursework.Info - Inspiration in an Instant

On the left is an image preview of every page of this document, and below are the first 150 words with formatting removed:

How does caffeine and ethanol affect the heart rate? Introduction At rest a normal adult heart beats around 75 times per minute. During strenuous exercise it may rise to 200 beats per minute. The SAN (sino-atrial node) controls the heart rate. Information is sent via two autonomic nerves that link the SAN with cardiovascular centre in the medulla of the brain, the rate increases or decreases depending on the information received. Factors, which affect the heart:> The secretion of adrenaline. This may be under stress, excitement or other emotions.> Movement of the limbs (exercise). Heart rate and breathing rate increase due to oxygen levels falling and levels of carbon dioxide rising.> Blood pressure. When blood pressure is too high, a mechanism prevents increase in heart rate. Adrenaline is a hormone, which is produced by the adrenal gland; it is usually secreted in tiny amounts, when stressed or scared. It raises...

Get instant access

• Instant, unlimited access to our documents in full
• Swap your work for free access, or pay £4.99
• To see the full version of this document and 146,186 others

OR

Receive email updates for this category

• Simply tell us your email address and receive a weekly Study Help Email for FREE
• Receive 3 FREE essay views with each email
• Get all the latest essays from Coursework.Info & discussion from TheStudentRoom.co.uk