Chapter 22 homeostasis fall'08

Chapter 22 homeostasis fall'08 - Homeostasis & Body...

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Unformatted text preview: Homeostasis & Body Org Homeostasis Chapter 22 Today we will Today Test results – Stem cell paper “now” due Nov 24, 2008 Homeostasis Homeostasis – Neg feedback – Pos feedback – Body sys act as one How are we organized Cells, tissues, organs, organ systems Homeostasis Claude Bernard @ 1850 Claude “constancy of the internal milieu” William Cannon @ 1920 homeostasis Homeostasis Homeostasis the maintenance of an internal environment the Homeostasis Homeostasis the maintenance of an internal environment the – Allows existence in adverse external Allows environments environments – A coordinated body effort coordinated Homeostasis Homeostasis the maintenance of an internal environment the – Allows existence in adverse external Allows environments environments – A coordinated body effort – Seeks dynamic equilibrium Seeks dynamic Narrow band of physical and chemical properties – Continual adjustment to changes needed Homeostasis Homeostasis the maintenance of an internal environment the – Allows existence in adverse external environments – A coordinated body effort – Seeks dynamic equilibrium Seeks dynamic Narrow band of physical and chemical properties – Continual adjustment to changes needed Equilibrium maintained by feedback systems Equilibrium feedback Negative Positive Negative Feedback Systems Negative Counteract the effect of change Or you could say production of (end) product triggers a response that stops the (end) product from forming We saw this in enzymes negative feed back negative Allosteric and competitive inhibition Neg feedback cont Neg Switch off Sensor Product producer Off Heat On Out of range + Temp OK End product Out of range - Sensor Switch on Neg feedback cont. Neg Neg feedback cont. Neg 3 items required items Control center Control w/set point w/set 1 Effector Sensor Sensor 1 2 3 3 2 Neg feedback cont. Neg example of how it works in body Body temp – – – – – – – – Nerve endings sense cold 2 Hypothalamus told body is Hypothalamus below 1degree set point 98.6 below Hypothalamus tells body to Hypothalamus 1 start warming mechanisms Body heats by shivering, blood Body vessels contract, metabolic 3 rate increased rate Body temp rises Sensed by nerves 2 Set point reached Hypothalamus sends signal to 1 Hypothalamus shut down warming mechanisms 3 mechanisms 1 2 3 Negative feedback cont. Negative other things regulated by negative feedback Blood oxygen content Blood Water balance Water Water Water Blood sugar le ve ls positive feedback positive Drives events to a conclusion A change is sensed and change the response to that change the intensifies intensifies 1 that change that 2 Note: feedback mechanism still has 3 parts: Control center, effector, and sensor 3 Real world positive feedback example example Usually self limiting Usually infrequent Real world positive feedback Usually self limiting Usually Usually infrequent Example: childbirth Example: contractions contractions 1 – 2– – Head against cervix Stretch sensed; signal to Hypothalamus releases 1 Hypothalamus hormone that prompts stronger contractions 3 stronger – Head forced against cervix, Head etc. 2 1 3 Etc. etc. – Cycle terminated by birth 3 2 Homeostatsis Homeostatsis an integrated body effort an Concept Concept – Any cell is connected to any other cells Any through the circulatory and nervous systems through – Communication via chem signals e.g. Communication hormones hormones – Therefore digestion works with circulatory Therefore system which works with urinary system, etc. system Homeostatsis Homeostatsis an integrated body effort an Concept Concept – Any cell is connected to any other cells Any through the circulatory and nervous systems through Homeostatsis Homeostatsis an integrated body effort an Concept Concept – Any cell is connected to any other cells Any through the circulatory and nervous systems through – Communication via chemical signals e.g. hormones e.g. Homeostatsis Homeostatsis an integrated body effort an Concept Concept – Any cell is connected to any other cells Any through the circulatory and nervous systems through – Communication via chemical signals e.g. hormones e.g. – Therefore digestion works with circulatory Therefore system which works with urinary system, etc. system How are we organized? How Very well thank How are we organized? How Very well thank you Cells Smallest unit capable of supporting life; make Smallest make How are we organized? How Very well thank you Cells Smallest unit capable of supporting life; make make Tissues Structurally similar cells doing a specific function; make make How are we organized? How Very well thank you Cells Smallest unit capable of supporting life; make make Tissues Tissues Structurally similar cells doing a specific function; make Structurally make Organs Built of 2 or more tissues to do complex functions; form Built How are we organized? How Very well thank you Cells Smallest unit capable of supporting life; make make Tissues Tissues Structurally similar cells doing a specific function; make Structurally make Organs Built of 2 or more tissues to do complex functions; form Organ System 2 or more organs that function in a coordinated manner Tissues Tissues composed of similar cells that perform a specific function 4 major categories major – Epithelial – Connective – Muscle – Nerve Nerve Epithelial tissue Epithelial Made of epithelial cells Form, along with loose connective tissue, membranes – Create barriers (skin) Create or – Permeable = allow specific substances to move across them Permeable (lung lining) (lung Structure of tissue adapted to function Structure of tissue adapted to function Lung lining: thin, flattened, 1 layer Trachea lining: thick, elongated, with cilia Glands Glands Are specialized epithelial tissue (folded) Secrete a substance 2 categories Exocrine glands Endocrine glands Connective tissues Connective Serve mainly to support and bind other tissues 3 categories – Loose connective tissue e.g. dermis e.g. – Collagen + Loose connective tissue Loose Combines w/epithelial cells to form Combines membranes membranes – E.g. the loose connective tissue E.g. “dermis” “dermis” A network of collagen, a network protein protein Has blood capillaries, Has nerves, glands woven through it through All bathed in extracellular All fluid fluid Surrounds and cushions most Surrounds organs of the body organs Connective tissues Connective Serve mainly to support and bind other tissues 3 categories – Loose connective tissue e.g. dermis e.g. – Collagen + – Fibrous connective tissue Tendons and ligaments – collagen Connective tissues Connective Serve mainly to support and bind other tissues 3 categories – – Loose connective tissue e.g. dermis e.g. – Collagen + Fibrous connective tissue Tendons and ligaments – collagen – Specialized connective tissue 5 Specialized connective tissue Specialized Includes Includes Cartilage Bone Adipose And Lymph Blood MUSCLE TISSUE MUSCLE Made of contractile cells Made contractile aka: muscle cells or muscle fibers Can contract when stimulated 3 types – Smooth (embedded in walls of bladder, intestine, uterus, blood vessels Involuntary slow sustained contractions function – Cardiac (heart muscle) Involuntary control, spontaneously active, gap junctions function – Skeletal Skeletal Voluntary control Voluntary function Nervous tissue Nervous tissue Transmits electrical signals Makes up brain, spinal cord and nerves Composed of 2 types of cells – Neurons Generate and conduct electrical signals (to others) – Glial cell Insulates, supports, protects neurons New research > memory, consciousness, the ID axon Cell body dendrites Synaptic terminals Neuron Organs Organs Comprised of 2 or more tissues that function together The “skin” is a good example Has all four tissue types acting together Listen please Organ systems Organ = 2 or more interacting organs doing a common function amen amen ...
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