Feedback mechanisms Are used to either maintain or amplify (to increase) chemical systems in the body. Note: To determine the type of mechanism you must be able to determine the stimulus and response.

Feedback Mechanisms

Identify a Stimulus and Response Your dog chases the ball and you say “Good Boy!” Stimulus: __________________ Response:__________________ Your dog pees on the rug and you say “Bad Dog!” Stimulus:____________________ Response:____________________

Feedback Mechanisms Positive Feedback Negative Feedback The response will increase the stimulus Does not return to homeostasis but will cause more of the stimulus to happen. The response will decrease the stimulus or return the system back to homeostasis.

Feedback Mechanisms ? ? The dog pees on the rug and you say “Bad Dog!” Is this Positive or Negative Feedback? The dog chases the ball and you say “Good Boy!” Is this positive or Negative Feedback?

You have your head phones in listening to your favorite songs. Positive Feedback Negative Feedback What would be an example? What would be an example?

The Circulatory System

Functions To transport oxygen to the cells of the body so cells can continue Cell Respiration To Transport nutrients to the cells of the body

Parts Heart Blood Vessels Blood

Components of Blood Red blood cells White blood cells Platelets Plasma

What are Red Blood Cells? Also called erythrocytes Transport oxygen Contain Hemoglobin An iron containing protein that binds to oxygen Gives blood a red color

What are White Blood Cells? Also called leukocytes Can live for days, months or even years Guard against infection, fight parasites, and attack bacteria Can leave the circulatory system and go into the immune system fighting infection

What are two kinds of White Blood Cells? Phagocytes (eating cells) Engulf and digest bacteria and other disease causing bacteria Lymphocytes Produce antibodies that are proteins to help destroy pathogens

What are platelets? Cell fragments needed for clotting Clotting process Platelet comes in contact with edges of broken blood vessel and becomes sticky A cluster of platelets gathers around the wound forming a clot (scab)

What is plasma? Fluid part of blood (mostly made of water) Straw colored Transport fatty acids, hormones and vitamins Regulate osmotic pressure and blood volume Fight viral and bacterial infections Aid in blood clotting

What are blood vessels? Types of blood vessels Arteries (largest) Capillaries (smallest) Veins

What are arteries? Large, thick walled blood vessels Carry blood from the heart to the cells All arteries except the pulmonary artery carry oxygen rich blood

What are capillaries? Tiny blood vessels with walls that are only one cell thick Oxygen and nutrient absorption take place in the capillaries Also carbon dioxide and waste products move into the blood through the capillaries Diffusion of Oxygen and Carbon Dioxide occurs here in the lungs.

What are veins? Smaller than arteries but larger than capillaries Return blood to the heart Contain valves to keep blood flowing towards the heart

Parts of the Heart Aorta Pulmonary Artery Pulmonary Vein Superior Vena Cava Left Atrium Right Atrium Left Ventricle Right Ventricle Septum Inferior Vena Cava

Blood Flow Through the Heart Oxygen poor- 1.) Superior and inferior vena cava 2.) Right Atrium 3.) Right Ventricle 4.) Lungs Oxygen rich- 5.) Left Atrium 6.) Left Ventricle 7.) Aorta 8.) Body

Blood Flow Through the Body Pulmonary circulation Right side of the heart pumps blood from the heart to the lungs Systemic circulation Left side of the heart receives blood from the lungs and pumps it to the rest of the body

Feedback Mechanisms in the Circulatory System When human tissue, such as skin is torn or cut, all the cells near the damage send out a signal that activates the platelets in that area. A the platelets begin to form a plug, they send out chemical signals calling for more platelets in order to stop the bleeding. Stimulus:__________ Response:_________ Feedback:_________

Feedback Mechanisms in the Circulatory System When muscle cells are active they need more ENERGY (ATP). In cellular respiration, the Mitochondria uses Oxygen to make ATP. After you are done exercising, your breathing returns to a normal rate because the amount of Oxygen required by your cells has decreased. Stimulus: ______________ Response:______________ Feedback:_______________