Human Anatomy and Physiology 1.Pick up the handout. 2.You do have new seat assignments. There will be no changes nor complaints. 1.Pick up the handout. 2.You do have new seat assignments. There will be no changes nor complaints.

Homework  No homework!

Objectives  Define homeostasis.  Describe the basic function of a physiological feedback loop.  Give an example of a positive and a negative feedback loop.  Define homeostasis.  Describe the basic function of a physiological feedback loop.  Give an example of a positive and a negative feedback loop.

Anatomy and Physiology  Our final unit for the year!  Anatomy is the study of the structure of a living thing. For instance, organ names and locations.  Physiology is the study of the functions and life maintenance of a living thing. For instance, organ jobs and interactions.  The unit will be broken up into the study of the major mammalian organ systems, with emphasis on humans.  Our final unit for the year!  Anatomy is the study of the structure of a living thing. For instance, organ names and locations.  Physiology is the study of the functions and life maintenance of a living thing. For instance, organ jobs and interactions.  The unit will be broken up into the study of the major mammalian organ systems, with emphasis on humans.

Anatomy & Physiology  Nervous System  Endocrine System  Cardiovascular System  Respiratory System  Digestive System  Urinary System  Musculoskeletal System  Reproductive System  (Hopefully) Lymphatic/Immune System  Please fill out the preassessment. Points for completion, not correctness.  Nervous System  Endocrine System  Cardiovascular System  Respiratory System  Digestive System  Urinary System  Musculoskeletal System  Reproductive System  (Hopefully) Lymphatic/Immune System  Please fill out the preassessment. Points for completion, not correctness.

Levels of Organization  Does anybody recall the different levels of organization of living things? Starting with the smallest:  Cell organelle  _____  Does anybody recall the different levels of organization of living things? Starting with the smallest:  Cell organelle  _____

Levels of Organization  Does anybody recall the different levels of organization of living things? Starting with the smallest:  Cell organelle  Cell  _____  Does anybody recall the different levels of organization of living things? Starting with the smallest:  Cell organelle  Cell  _____

Levels of Organization  Does anybody recall the different levels of organization of living things? Starting with the smallest:  Cell organelle  Cell  Tissue  _____  Does anybody recall the different levels of organization of living things? Starting with the smallest:  Cell organelle  Cell  Tissue  _____

Levels of Organization  Does anybody recall the different levels of organization of living things? Starting with the smallest:  Cell organelle  Cell  Tissue  Organ  _____  Does anybody recall the different levels of organization of living things? Starting with the smallest:  Cell organelle  Cell  Tissue  Organ  _____

Levels of Organization  Does anybody recall the different levels of organization of living things? Starting with the smallest:  Cell organelle  Cell  Tissue  Organ  Organ System  _____  Does anybody recall the different levels of organization of living things? Starting with the smallest:  Cell organelle  Cell  Tissue  Organ  Organ System  _____

Levels of Organization  Does anybody recall the different levels of organization of living things? Starting with the smallest:  Cell organelle  Cell (ex: a cardiac muscle cell)  Tissue = A group of cells carrying out a specific function. (ex: a layer of heart muscle tissue)  Organ = A group of tissues carrying out a general function. (ex: the heart)  Organ System = A group of organs carrying out a major function. (ex: the cardiovascular system)  Organism  Does anybody recall the different levels of organization of living things? Starting with the smallest:  Cell organelle  Cell (ex: a cardiac muscle cell)  Tissue = A group of cells carrying out a specific function. (ex: a layer of heart muscle tissue)  Organ = A group of tissues carrying out a general function. (ex: the heart)  Organ System = A group of organs carrying out a major function. (ex: the cardiovascular system)  Organism

Central Theme  We learned a general overview of how cells maintain their lives, we learned a general overview of how structures like organs and the organization of tissues developed through time, and the focus in this unit is on:  HOMEOSTASIS  (don’t suppose anybody remembers this word?)  We learned a general overview of how cells maintain their lives, we learned a general overview of how structures like organs and the organization of tissues developed through time, and the focus in this unit is on:  HOMEOSTASIS  (don’t suppose anybody remembers this word?)

Central Theme  HOMEOSTASIS: Regulation of the internal environment to achieve a stable, constant condition.  Maintaining a stable body temperature, energy, pH, etc. Basically, keeping the body at the level of stability that permits survival.  The organ systems are all about the different ways that parts of the body contribute to maintaining homeostasis.  HOMEOSTASIS: Regulation of the internal environment to achieve a stable, constant condition.  Maintaining a stable body temperature, energy, pH, etc. Basically, keeping the body at the level of stability that permits survival.  The organ systems are all about the different ways that parts of the body contribute to maintaining homeostasis.

Homeostasis  For instance, maintaining a stable, constant level of blood sugar…

Homeostasis  A significant way that this is done is through physiological feedback loops.  What’s feedback?  What’s a loop?  A significant way that this is done is through physiological feedback loops.  What’s feedback?  What’s a loop?

Homeostasis  A physiological feedback loop is the body regulating itself in response to a stimulus.  Two kinds: positive and negative feedback loops.  A physiological feedback loop is the body regulating itself in response to a stimulus.  Two kinds: positive and negative feedback loops.

Homeostasis  Positive feedback loop: In response to a rising level of the input, you get more of the output.  What ever is out of balance becomes more out of balance.  A positive feedback loop, in terms of the body, more often than not disrupts homeostasis rather than maintains it.  So-called “vicious cycle.”  Positive feedback loop: In response to a rising level of the input, you get more of the output.  What ever is out of balance becomes more out of balance.  A positive feedback loop, in terms of the body, more often than not disrupts homeostasis rather than maintains it.  So-called “vicious cycle.”

Positive Feedback Loops  Another example: oxytocin stimulating contractions

Negative Feedback Loop  Negative feedback loop: In response to a rising level of the input, you decrease the output.  Whatever is out of balance becomes less out of balance.  Essential to maintaining homeostasis.  Negative feedback loop: In response to a rising level of the input, you decrease the output.  Whatever is out of balance becomes less out of balance.  Essential to maintaining homeostasis.

Negative Feedback Loop  Another example is body temperature.  As temp rises, nerves signal capillaries to dilate, which releases some heat.  When temp is too low, other nerves signal capillaries to contract, conserving heat.  Another example is body temperature.  As temp rises, nerves signal capillaries to dilate, which releases some heat.  When temp is too low, other nerves signal capillaries to contract, conserving heat.

Feedback Loops  To get used to the idea of a feedback loop, I want you to think of at least four more, two positive and two negative.  They don’t have to be physiological. They could be human activities, environmental, something from a movie or video game, anything.  Diagram each one, and label them as positive or negative. Handed in for credit.  Grade not given for beautiful art or anything, just for whether or not I can tell that yes, this is a negative feedback loop.  To get used to the idea of a feedback loop, I want you to think of at least four more, two positive and two negative.  They don’t have to be physiological. They could be human activities, environmental, something from a movie or video game, anything.  Diagram each one, and label them as positive or negative. Handed in for credit.  Grade not given for beautiful art or anything, just for whether or not I can tell that yes, this is a negative feedback loop.