8 - The Endocrine System

Is a series of glands that produce and secrete hormones that the body uses for a wide range of functions

• respiration • metabolism • reproduction Helps to play an important role in homeostasis because hormones regulate activity of the body cells

The ability of the body to maintain a stable internal environment despite changes in external conditions

Molecules that signal a target cell to “do something”

• hypothalamus • pituitary gland • pineal gland • thyroid gland • Thymus • adrenal gland • pancreas • ovaries • testes

Secretes melatonin

Responsible for the metabolic process

Senses the bodies needs and sends signals

Metabolism, growth, heart, digestive function

Enables the body to deal with stress and controls energy

• AIDS in food digestion - controlling energy levels of blood

Produces eggs

Produces Sperm

Travel around the body in the blood. Examples: Adrenaline and testosterone

Act on neighboring cells without entering the bloodstream and are usually inactivated quickly. Examples: glucagon and Seratonin

Release of most hormones occur in short bursts yet some occur over long periods of time in order to stimulate permanent changes in the body

Hormones effect only specific target cells by chemically binding to specific receptors Hormones are secreted by endocrine glands to regulate and coordinate a range of bodily functions

• signal from the nervous system such as adrenaline • chemical changes in the blood such as insulin • other hormones such as growth hormones

• both responsible for maintaining homeostasis • both apart of the brain • the pituitary is located under the hypothalamus • the hypothalamus controls the pituitary gland • Neurohormones from the hypothalamus directly affect the pituitary gland • nerve impulses from the hypothalamus also stimulate the pituitary gland The pituitary gland secretes growth hormones that help regulate a wide range of bodily functions including growth, water and temperature regulation

• when a product of a reaction leads to an increase in that reaction / reinforce or increase changes in controlled conditions • an event will occur to discontinue the feedback • generally control infrequent conditions Examples: Urine contractions / childbirths

When a product of a reaction leads to a decrease in that reaction / reverse system in the controlled condition / brings the body back to balance Example: most feedback mechanism s regulate hormones in the human body

Increase heart rate • prepares the body for a flight or fight response • increase heart rate • increase blood pressure • dizziness • enlarging pupils • tunnel vision • hearing loss • slow digestion • shaking • dry mouth

Decreases heart rate

Anti-diuretic Hormones helps to control blood pressure by acting in the kidneys and he blood vessels. It’s most important role is to conserve the fluid volume of your body by reducing the amount of water passed out in urine When someone is dehydrated ADH will absorb more water