Coordination and Control (the human endocrine system)

• The endocrine system secretes hormones into the bloodstream from glands throughout the body.
• Hormones produce an effect on specific target organs in the body.
• Hormonal negative feedback systems are a part of Higher.
• Thyroxine and adrenaline are hormones that are studied in Higher.
• Control of blood glucose concentration is a part of Type 1 and Type 2 Diabetes.
• Glucagon plays a role in blood sugar levels in Type 1 and Type 2 Diabetes.
• The role of reproductive hormones in puberty is a part of the study of hormones and nerves.
• The Pituitary gland controls the water content of the blood by increasing the reabsorption of water by the collecting ducts.
• Adrenaline, which is produced by the Adrenal glands, has several targets including the respiratory and circulatory systems, and is used in preparation for 'fight or flight' by increasing breathing rate, heart rate, flow of blood to muscles, and conversion of glycogen to glucose.
• Insulin, which is produced by the Pancreas and stored in the Liver, controls blood glucose levels by increasing the conversion of glucose into glycogen for storage.
• ADH, which is produced by the Pituitary gland and controls the water content of the blood by increasing the reabsorption of water by the collecting ducts.
• A hormone is a chemical messenger produced in glands and carried by the blood to specific organs in the body.
• An organ or tissue that makes a substance for release, such as a hormone, is a gland.
• Hormones can control the body, and the effects are much slower than the nervous system, but they last for longer.
• There are important differences between nervous and hormonal control.
• Nervous hormonal type of signal is electrical (chemical at synapses), while nervous and hormonal types of signal transmission are both chemical.
• Nervous and hormonal types of signal transmission occur by nerve cells (neurones) and by the bloodstream respectively.
• Effectors for nervous and hormonal types of signal transmission are muscles or glands, and target cells in particular tissues respectively.
• Nervous and hormonal types of response include muscle contraction or secretion, and chemical change respectively.
• Nervous and hormonal types of signal have very different speeds of response, with nervous type being very rapid and hormonal type being slower.
• Nervous and hormonal types of signal have different durations of response, with nervous type being short (until nerve impulses stop) and hormonal type being long (until hormone is broken down).
• The pituitary gland is known as a 'master gland' as it secretes several hormones into the blood in response to the body's condition, such as blood water levels.
• These hormones can also act on other glands to stimulate the release of different types of hormones and bring about effects.
• The body produces a range of different chemical hormones that travel in the bloodstream and affect a number of different organs or cells in the body.
• Important hormones released into the bloodstream include ADH (anti-diuretic hormone), adrenaline and insulin.