A-level Biology OCR [New Spec] - Endocrine System: Hormones | A-level Biology | OCR, AQA, Edexcel

Endocrine System: Hormones in a Snap! Unlock the full A-level Biology course at http://bit.ly/2VZhn9W created by Adam Tildesley, Biology expert at SnapRevise and graduate of Cambridge University. The key points covered of this video include: 1. What is a Hormone 2. Endocrine Glands What is a Hormone Hormones are signalling molecules that are released into the blood. Because they are released into the blood, hormones can contact almost all the cells in the body. Only those cells with receptors for the hormone are affected. These are the target cells. For any given hormone, target cells are cells in the body that have a specific receptor for that hormone. Endocrine Glands Endocrine glands are glands in the endocrine system that release hormones straight into the blood. The endocrine system is the hormonal system - it is a communication system that uses hormones as signalling molecules. They differ from exocrine glands that secrete molecules into a tube called a duct, which takes molecules to where they are used. For instance, the pancreas contains exocrine glands that secrete digestive enzymes into the small intestine. The pancreas also contains endocrine glands that secrete the hormone insulin straight into the blood. Endocrine glands include the pancreas, pituitary gland, testes and ovaries. Summary A hormone is a signalling molecule released from an endocrine gland An endocrine gland is a group of cells that secrete hormones directly in to the blood These differ from exocrine glands, which secrete molecules into a duct Hormones travel around the blood where they meet cells with a receptor for that hormone - target cells