Presentation on theme: "Weird Body Quirks Brain freeze"— Presentation transcript:
1Weird Body Quirks Brain freeze “Ice cream headaches” happen when something cold touches nerves in the roof of the mouth, triggering blood vessels in the front of your head to constrict -- producing pain. Try this quick pain relief trick: Press your tongue to the roof of your mouth to warm it up.
2HOMEOSTASIS & Control Systems UNIT 4Also Known As…If it ain’t broken, don’t waste my valuable time & energy trying to fix it, fool!
3Learning goals . . .To explain the process of maintaining homeostasis through feedback loops and their components.You will show your understanding by . . .Presenting an explanation (diagramatic, written or kinesthetic) of thermoregulation
4What happens in your body when you do a Triathalon? Cell Resp increasesBody Temp increases to 39 degrees Celsius (due to heat from CR rxns)Sweat is produced to dissipate heatThis loss of water, drops blood pressureHeart responds, Kidneys conserve waterElectrolytes (salts) are lost in sweatBody must use hormones to keep a steady supply of glucose to CR pathwaysNervous systems monitors o2 levels, increasing breathing rate if necessaryNervous systems also work with the circulatory system to divert blood to essential areas (muscles, brain, heart…away from stomach etc)
6The “Ideal Body State” 37 degrees 0.1% blood sugar Blood pH 7.35 Environment doesn’t always allow for this!Organs and body systems are constantly adapting
7HomeostasisMaintenance of a relatively stable internal, fluid environment (internal milieu) despite a changing external environmentHomios = Similar Stasis = Standing StillTemperature37oC (98.6oF)Blood pH7.35Blood sugar level0.1%
8Homeostasis All of our organ systems work together to maintain HomeostasisHomeostasis is a steady internalstate, keeps conditions in the bodyconstant.Examples:Blood Pressure (circulatory system)Respiration Rate (respiratory system)Body Temperature (circulatory system)Blood Sugar (digestive and circulatory)The brain and the adrenal system(hormones) do most of theregulating.
9Homeostatic Control Mechanisms MonitorsSenses state of system(Brain stem receptors detect increased CO2 in the blood)Coordinating CentreReceives incoming info about system and decides what the next steps should be(Nerve cells in brain receive and send a signal to the diapragm)RegulatorCarries out the appropriate next step to keep system at homeostasis(Diaphragm increases depth and rate of breathing)Monitor sales and stock of stores and report to factory manager. Based on stocks, factory manager instructs more or less of something to be made. Works increase or decrease production of certain items.
10Homeostatic Control System StimulusDeviation from set pointResponseMove system towards set pointSensorConstantly monitors conditionsNegative feedback (-)Integrating CentreCompares conditions to a set point based on a desired valueEffectorCauses changes to compensate for deviation
11Dynamic Equilibrium There will always be fluctuations in levels Homeostatic mechanisms ensure that all body systems function within an acceptable range.Mammalian Diving ReflexCheck out the ICEMAN!esHomework…Read p (Feedback)Do Q 2, 3, 4, 9, 10 p348
12Feedback Mechanisms/Loops Positive feedback - a mechanism by which an output is enhancedContractions in childbirth: contractions stimulate oxytocin which stimulates more muscle contractionsNegative feedback mechanism consists of reducing the output or activity of any organ or system back to it's normal range of functioning.Blood vessels can sense resistance of blood flow against the walls when blood pressure increases. The blood vessels act as the receptors and they relay this message to the brain. The brain then sends a message to the heart and blood vessels, both are the effectors. The heart rate would decrease as the blood vessels increase in diameter. This change would result in the blood pressure to fall back to its normal range. The opposite would happen when blood pressure decreases.
14Negative feedback - a mechanism by which an output is diminished Any change from normal range of function is resisted in negative feedback.The change initiates responses that bring the function of the organ back to its normal range.Negative feedback loops require a Receptor, A Control Center, and Effectors.Blood vessels have receptors (monitors) which can measure the resistance of blood flow against vessel wallsThe brain (control center) receives info about change in body’s internal conditions, sends out signals via nervesEffectors (regulators) - the muscles, organs, and other structures that receive signals from the control center and respond to correct the deviation.Most controls in the body are negative.
16Negative Feedback in the Home? Negative feedback can be likened to your home’s heating system.Temperature too high…Thermometer (monitor) senses increase in temperature.Signal sent to thermostat (coordinating centre) and thermostat says we better cool it down.Thermostat tells air conditioner (regulator) to start pumping in the cold air.Once house is cooled…system rests – why waste the energy?
18Negative feedback in the home? What if the temperature is too low?Thermometer senses that it is too cold and sends signal to thermostat.Thermostat figures it is time to turn up the heat.Thermostat tells furnace to get going and heat the place up.Once temperature is back up to normal levels, the system rests – why waste the energy?Saving energy is important to any energy being like yourself…
19Example of Negative feedback: Blood Pressure Regulation Negative feedback mechanism consists of reducing the output or activity of any organ or system back to it's normal range of functioning.Blood vessels can sense resistance of blood flow against the walls when blood pressure increases. The blood vessels act as the receptors and they relay this message to the brain. The brain then sends a message to the heart and blood vessels, both are the effectors. The heart rate would decrease as the blood vessels increase in diameter. This change would result in the blood pressure to fall back to its normal range. The opposite would happen when blood pressure decreases.
20Thermoregulation Also known as… Why do students complain when the room is too hot or too cold when their own bodies are gonna look after them anyways!!!
21ThermoregulationThermoregulation is the maintaining of a stable body temperature.This is necessary for the cells to function properly because the “rock star” proteins might decide to lose it if the room is not just right!The brain is the monitor and coordinating centre in this process is the hypothalamus – a part of the brain that is in the centre of the head and lies below the thalamus but above the pituitary gland.Hypothalamus – Region of the vertebrate’s brain responsible for coordinating many nerve and hormone functions.
22Ecto Vs. EndoEctotherms – Invertebrates, fish, amphibians, reptiles...Depend on air temp to regulate body temp.Endotherms – Mammals – Are able to maintain a constant body temp regardless of surroundings.
24Physiological Response ThermoregulationStimulusPhysiological ResponseAdjustmentDecreased Enviro Temp-Constriction of blood vessels-Hairs stand on end-Shivering-Heat is conserved-More heat is generated by increased metabolismIncreased Enviro Temp-Dilation of blood vessels of skin-Sweating-Heat is dissipatedWhat happens when the body gets too hot?The brain senses the increase in temperature and sends a signal to hypothalamus which tells sweat glands to start sweating and blood vessels near the surface of the skin to dilate (open wide).Evaporation of sweat cools the body – blow across the back of your hand…Now lick the back of your hand and blow across it. Your spit is evaporating (as sweat would) and it is cooling you down.Wider blood vessels means more blood to skin surface which is cooler. Blood cools and is sent back to the core of body to help lower temperature.What happens when the body gets too cold?The brain senses the drop in temperature and sends a signal to the hypothalamus to do something.The hypothalamus sends a signal to the muscles to contract rapidly and a signal to the blood vessels near the skin to constrict (become smaller in diameter).Rapid muscle contraction builds up heat – it’s like a mini workout.The smaller blood vessels reduces blood flow to the skin where the cold is and therefore less blood gets cooled and sent back to the core of the body.When the body is back to normal, the process stops.
25Tomorrow:RAFT:“Drugs such as ecstasy interfere with the feedback mechanism that helps maintain a constant body temperature.” Explain why these drugs are dangerous.