BIG BANG THEORY

HOMEOSTASIS

Maintenance of a stable internal environment A dynamic state of equilibrium Homeostasis is necessary for normal body functioning Communication within the body Nervous and endocrine system (nerves and hormones)

FEEDBACK LOOP TERMS Receptor: a sensory organ Stimulus: an action that evokes a response Effector: an organ that acts in response Response: the caused action of the effector Control Center: determines the level at which a variable is to maintained, analyzes info, determines response

Figure 1.4, step 1a Variable (in homeostasis)

Figure 1.4, step 1b Stimulus: Produces change in variable Variable (in homeostasis) Imbalance

Figure 1.4, step 2 Change detected by receptor Stimulus: Produces change in variable Receptor (sensor) Variable (in homeostasis) Imbalance

Figure 1.4, step 3 Change detected by receptor Stimulus: Produces change in variable Input: Information sent along afferent pathway to Receptor (sensor) Variable (in homeostasis) Control center Imbalance

Figure 1.4, step 4 Change detected by receptor Stimulus: Produces change in variable Input: Information sent along afferent pathway to Receptor (sensor) Effector Variable (in homeostasis) Output: Information sent along efferent pathway to activate Control center Imbalance

Figure 1.4, step 5 Change detected by receptor Stimulus: Produces change in variable Input: Information sent along afferent pathway to Receptor (sensor) Effector Variable (in homeostasis) Response of effector feeds back to influence magnitude of stimulus and returns variable to homeostasis Output: Information sent along efferent pathway to activate Control center Imbalance

NEGATIVE FEEDBACK LOOP Receptor: a sensory organ Stimulus: an action that evokes a response Effector: an organ that acts in response Response: the caused action of the effector

NEGATIVE FEEDBACK LOOP PRACTICE (SPEED SIGN)  Receptor: a sensory organ  Stimulus: an action that evokes a response  Effector: an organ that acts in response  Response: the caused action of the effector

FEEDBACK LOOP PRACTICE (THERMOSTAT)  Receptor: a sensory organ  Stimulus: an action that evokes a response  Effector: an organ that acts in response  Response: the caused action of the effector

FEEDBACK LOOP PRACTICE (THERMOSTAT)  Receptor: a sensory organ  Stimulus: an action that evokes a response  Effector: an organ that acts in response  Response: the caused action of the effector

THERMOREGULATION

Capillaries Sweat Glands Muscles Capillaries Body Hair

BLOOD GLUCOSE Read the article titled Insulin and Glucagon Work in a groups of 2-3 to construct a negative feedback loop like we practiced Identify receptor, effectors, stimuli, and responses Draw and label a negative feedback loop

BLOOD GLUCOSE Body Cells Liver Liver

BLOOD GLUCOSE Body Cells Liver Liver Insulin (Beta Cells)

BLOOD GLUCOSE Body Cells Liver Liver Insulin (Beta Cells) Glucagon (Alpha Cells)

POSITIVE FEEDBACK MECHANISMS Increases the original stimulus to push the variable farther In the body this only occurs in blood clotting and during the birth of a baby

HOMEOSTASIS LAB