Homeostasis Which systems control body functions? How does your body stay in balance?

Which systems control body functions? The nervous system and endocrine system work together to control body functions Glands are organs that release chemical signals directly into the blood stream

Nervous system A signal in the environment that makes you react is called a stimulus A response is what your body does in reaction to a stimulus

Endocrine system The chemical signals released by the endocrine system are called hormones One hormone controls the amount of water in the blood One hormone controls the amount of sugar in the blood

How does your body stay in balance? Homeostasis is the condition in which an organisms internal environment is kept stable in spite of changes in the external environment

Regulating temperature When you are cold, your nervous system sends signals to make you shiver When you are hot, you endocrine system releases hormones that make you perspire Changes in the amount of blood flow to the skin helps prevent heat loss

Meeting energy needs If your body needs more energy, hormones from the endocrine system signal the nervous system to make you feel hungry Your digestive system, and circulatory system also play major roles

Maintaining water balance If your body needs more water, you feel thirsty Excess water is released through excretory system when you exhale, sweat, or breathe.

Ongoing stress can disrupt your body’s ability to fight disease Responding to stress Stress is the reaction of your body to possibly threatening, challenging, of uncomfortable events Ongoing stress can disrupt your body’s ability to fight disease

Fighting disease The immune system includes specialized cells that can attack and destroy viruses, and bacteria Fighting disease requires more energy causing your body temperature to go up

Identify the main systems involved: Sweat appears on the surface of the runners skin, and carbon dioxide moves rapidly out of her lungs. Cell wastes ,move into her blood and are filtered by her kidneys

Which systems? Food from the runner’s breakfast has been broken down into nutrients and is delivered to cells

Which systems? A runner’s brain interprets what her eyes see and directs her movements

Which systems? Hormones move through the runner’s bloodstream, stimulating her body systems to work harder

Which systems? The runners breathing rate and heart rate increase, supplying more oxygen to her muscle cells