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HUMAN PHYSIOLOGY

HUMAN PHYSIOLOGY. Objectives: Define homeostasis Describe mechanisms used by the human body to maintain balance Identify how the body uses these mechanisms to maintain homeostasis. HOMEOSTASIS. Tendency towards a relatively stable state or equilibrium (balance) Examples:

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HUMAN PHYSIOLOGY

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  1. HUMAN PHYSIOLOGY Objectives: Define homeostasis Describe mechanisms used by the human body to maintain balance Identify how the body uses these mechanisms to maintain homeostasis

  2. HOMEOSTASIS • Tendency towards a relatively stable state or equilibrium (balance) • Examples: • Body Temperature 98.6 F • Blood has a neutral pH = 7

  3. Mechanisms Use to Maintain Homeostasis • Electro-chemical signals  quick messages transferred by the nervous system • Negative feedback mechanisms  long term responses often carried out by hormones • Lock and Key  controls transmission of messages based on a shape configuration at the cellular level

  4. Negative Feedback Mechanisms • Any change from the normal range of function is opposed or resisted • Two responses that work in opposition • Examples: • Blood pressure • Temperature • Respiration rate • Blood glucose levels

  5. Negative Feedbackand Blood Sugar

  6. Lock and Key Model Defined • Molecules have a shape that only fits specific receptors • Ex. Square peg only fits into square hole, star peg only fits into star hole • Enzymes  chemical proteins in the body that assist or speed up chemical reactions (catalyst) http://highered.mcgraw-hill.com/sites/0072495855/student_view0/chapter2/animation__how_enzymes_work.html

  7. Communication • Cells communicate with one another by releasing chemicals. • These chemicals bind to receptors on the surface of other cells • The chemicals may be delivered to nearby cells or cells across the body (using the blood stream) • When the lock and key is formed, the message has been sent http://www.youtube.com/watch?v=U6uHotlXvPo

  8. Determining “Self” from Invaders • Your bodies immune (defense) system needs to be able to determine what is “self” and what is an invader • It uses the lock and key method to determine invaders from self http://www.youtube.com/watch?v=cL9KY_ECzfo

  9. Using Lock and Key Model in Therapies • Scientists create drugs that mimic (look like) messenger molecules • These messenger molecules may activate the response • Or the molecule may fit, but not perfectly, so the hole is blocked and the message CANNOT be sent

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