14.3-4 Hormones

14.3 Hormones in humans

• Define a hormone as a chemical substance, produced by a gland and carried by the blood, which alters the activity of one or more specific target organs

• Identify specific endocrine glands and their secretions, limited to adrenal glands and adrenaline, pancreas and insulin, testes and testosterone and ovaries and oestrogen

• Describe adrenaline as the hormone secreted in ‘fight or flight’ situations and its effects, limited to increased breathing and pulse rate and widened pupils

• Give examples of situations in which adrenaline secretion increases

• State the functions of insulin, oestrogen and testosterone

Supplement

• Discuss the role of the hormone adrenaline in the chemical control of metabolic activity, including increasing the blood glucose concentration and pulse rate

• Compare nervous and hormonal control systems in terms of speed and longevity of action

14.4 Homeostasis

• Define homeostasis as the maintenance of a constant internal environment

• Name and identify on a diagram of the skin: hairs, hair erector muscles, sweat glands, receptors, sensory neurones, blood vessels and fatty tissue

• Describe the maintenance of a constant internal body temperature in humans in terms of insulation, sweating, shivering and the role of the brain (limited to blood temperature receptors and coordination).

Supplement

• Explain that homeostasis is the control of internal conditions within set limits

• Explain the concept of control by negative feedback

• Describe the control of the glucose concentration of the blood by the liver and the roles of insulin and glucagon from the pancreas

• Outline the symptoms and treatment of type 1 diabetes (detail of β cells is not required)

• Describe the maintenance of a constant internal body temperature in humans in terms of vasodilation and vasoconstriction of arterioles supplying skin surface capillaries.