Endocrine System Year 9 Science

Endocrine system It releases hormones into the blood to signal other cells to behave in certain ways. They are chemicals that are released slowly from different glands throughout the body.

Interaction of Glands The hypothalamus is located in the brain and controls the release of hormones from the pituitary gland. It is an important link between the endocrine and nervous systems.

Hormones Hormones are chemical substances that usually act as messengers in the body. Hormones are made by endocrine glands and released into the bloodstream or the fluid surrounding cells and send signals to target organs. They are slower to act than the nervous system

Pituitary Gland Located at the base of the brain It secretes nine hormones that regulate many body functions and controls functions of other glands. It's often called the "master gland“. The production and secretion of pituitary hormones can be influenced by factors such as emotions and changes in the seasons. To accomplish this, the hypothalamus provides information sensed by the brain (such as environmental temperature, light exposure patterns, and feelings) to the pituitary.

Thyroid The thyroid is located in the neck, just below the Adam’s apple It is controlled by hormones from the pituitary. It produces the hormone thyroxin which is involved in controlling metabolism, heart rate, heat regulation, and brain development. The production and secretion of pituitary hormones can be influenced by factors such as emotions and changes in the seasons. To accomplish this, the hypothalamus provides information sensed by the brain (such as environmental temperature, light exposure patterns, and feelings) to the pituitary.

The Adrenal Glands The body also has two triangular adrenal glands, one on top of each kidney. It controls the rate at which your heart beats and your breathing due. It secretes the hormone adrenaline which increases your heartbeat and breathing when your frightened or nervous. It provides a “fight or flight” response

Pancreas The pancreas produces two important hormones, insulin and glucagon. These hormones together maintain a steady level of glucose, or sugar, in the blood.

Female Gonads – Ovaries Produce ova (eggs) and secrete the female hormones estrogen & progesterone. Estrogen is involved in beginning puberty Estrogen and progesterone are also involved in the regulation of a girl's menstrual cycle. These hormones also play a role in pregnancy.

Males Gonads - Testes The male gonads, or testes are located in the scrotum. They secrete hormones called androgens, the most important of which is testosterone.