Transcript Homeostasis
OBJECTIVE AND CATALYST Students will: define homeostasis and explain how body systems maintain homeostasis through feedback Catalyst: Pd 10—My apologies, new grades TOMORROW. What comes to your mind when you hear the following terms? HOMEOSTASIS FEEDBACK REGULATION AGENDA Catalyst Study Tips Review Riddle/Introduce New Riddle Homeostasis Notes REMINDERS AND HOMEWORK Create a Crossword Puzzle for Body Systems and Organelles DUE Thursday, December 1, 2011 QUIZ on Friday! Coach Class TODAY STUDY TIPS How can we study for this test? RIDDLES OBJECTIVE AND CATALYST Students will: define homeostasis and explain how body systems maintain homeostasis through feedback Catalyst: 1. 2. 3. 4. 5. Review: Name the body system that… Controls the body through electrical signals Removes waste Allows movement Controls the body through chemical signals Transports nutrients and oxygen HOMEOSTASIS and Body Systems CHARACTERISTICS OF LIVING THINGS Living things must perform all of the following functions: Movement Respiration Sensitivity Nutrition Excretion/Remove waste Reproduction Growth CHARACTERISTICS OF LIVING THINGS Living things must perform all of the following functions: Movement Respiration Sensitivity/Homeostasis Nutrition Excretion/Remove waste Reproduction Growth HOW DO GYMNASTS DO THIS? IT’S A BALANCING ACT …just like Homeostasis. HOMEOSTASIS Homeostasis – maintaining a stable INTERNAL environment Aka “Staying Balanced” What characteristic of life (MRS.NERG) refers to homeostasis? What are some ways that our bodies maintain homeostasis when our external environment changes? REVIEW Cells > Tissues > Organs > Organ Systems > Organisms Maintaining homeostasis begins at CELLULAR level Cell Membrane is the organelle responsible for maintaining homeostasis HOMEOSTASIS IN UNICELLULAR ORGANISMS Can single celled organisms maintain homeostasis? Support your answer in the space provided in your notes. UNICELLULAR ORGANISMS Yes! To be considered a living organism, organisms must be able to maintain homeostasis—a stable internal environment One way is by using a contractile vacuole to remove excess water! Paramecium Vacuole UNICELLULAR ORGANISMS Move materials in and out using the cell membrane. In direct contact with external environment unlike multicellular organisms Just move wastes out of the cell and be done with them Do not have tissues, so all homeostasis is controlled by the cell membrane moving materials in and out HOMEOSTASIS IN MULTICELLULAR ORGANISMS Tissues are groups of cells that do the same job, and an organ is a group of tissues that do the same job. Cells get rid of wastes and create energy but they need other tissues to move things out of the body since the cells are not in direct contact with their external environment MULTICELLULAR ORGANISMS Name 3 organs in the body The organs each work in systems that do jobs that keep our bodies in homeostasis. How do these organs maintain homeostasis? What do they do? Write your answers next to the organs. FEEDBACK Homeostasis in multicellular organisms maintained through feedback mechanisms Negative feedback Sensors notice something off balance Sensors then trigger a response to get things back to normal Once back to normal, response stops THERMOSTATS How does the thermostat in your house work? Describe the function in the space on your notes. Think of it like a thermostat in your house. It is set for a specific temperature. When the room gets too cold, the thermostat senses the drop and turns on the heat. When the room warms up, the thermostat senses the increase and the heat turns off. NEGATIVE FEEDBACK DURING EXERCISE RUNNING IS ANOTHER EXAMPLE OF FEEDBACK Running makes body temperature increase Sensors detect increase and dilate pores in skin You begin to sweat to cool down Your body temperature decreases You stop sweating “THE INCREDIBLE HUMAN MACHINE” SWEATING IS HOMEOSTASIS! Watch the VIDEO CLIP As you watch, answer the questions on your handout. VIDEO QUESTIONS: How does the body cool itself? What happens if we are cold? What is one way the body retains heat? How is eating a cookie, piece of candy, or cupcake going to cause a feedback loop to start? BY REGULATING BLOOD SUGAR LEVELS USING INSULIN (EXAMPLE 2) You eat a piece of candy and your blood sugar levels increase Your increased levels of blood sugar set off a signal that is sent to the brain The brain then tells the Pancreas (part of the endocrine system) to release insulin a hormone used to break down carbohydrates (sugar) REGULATING BLOOD SUGAR When blood sugar levels are low enough the insulin stops being released allowing blood sugar levels to rise. When they get too high, this happens all over again! DIABETICS Why do diabetics have to test their blood sugar levels? How is Diabetes a disruption to homeostasis? MULTICELLULAR Once materials are moved out of the cell, using feedback mechanisms, organs perform jobs to maintain homeostasis Maintaining homeostasis by: Transporting Materials Removing Waste Controlling Temperature Controlling Movement Digesting/ breaking down food molecules Multicellular organisms like humans have organ systems (groups of organs) that each have specific jobs to help maintain homeostasis Organ Systems- lets write their functions for review! Circulatory Respiratory Muscle/Skeletal Digestive Excretory Endocrine Nervous EXAMPLE –REGULATING BODY TEMPERATURE Example: The body maintains homeostasis by regulating its internal temperature When the body gets too warm, during exercise, the circulatory system pumps blood faster to cool off the body, and the skin begins to sweat. If the body is too cold, the heart pumps blood more slowly, and the skin gets goose bumps which raise the hairs to trap a thin layer of air by the skin to keep heat in. Also, your muscles begin to contract and relax quickly causing you to shiver but really that’s generating heat. REGULATING BODY TEMPERATURE What organ systems are involved in this process? CHOOSE YOUR ADVENTURE Using my example as help, choose one of the other 4 ways to maintain homeostasis and make a list of the body systems that are needed to carry-out that task! HOMEOSTASIS PRACTICE Brain Pop Video Answer the questions as we watch the video. HOMEOSTASIS PRACTICE The following scenarios are all examples of organisms maintaining homeostasis. Describe the initial change (cause), if that change was internal (inside) or external (outside), and the organisms response (effect) Ex. A wolf pants after chasing a rabbit to kill Initial change (cause)—chasing rabbit Internal/External—internal Response—Panting WHAT HAPPENS WHEN HOMEOSTASIS FAILS? Read your assigned reading and answer the four questions on your handout. BE PREPARED TO SHARE WITH YOUR GROUP! EXIT SLIP Give 3 examples of your body maintaining homeostasis EXIT SLIP Fill in the “L” and “H” sections of your KWLH Chart. What have you learned? How did you learn it? (What are the most effective ways you learned information?)