Homeostasis and Feedback

Size: px

Start display at page:

Download "Homeostasis and Feedback"

Audrey Jenkins
5 years ago
Views:

1 Homeostasis and Feedback

2 Homeostasis The body keeps balanced by a process called HOMEOSTASIS. Homeostasis means the body maintains a CONSTANT internal environment

3 REVIEW: Characteristics of Life 1. made up of basic units called cells 2. are based on a universal genetic code 3. obtain and use materials and energy 4. grow and develop 5. reproduce 6. respond to their environment 7. maintain a stable internal environment 8. change over time

4 Homeostasis Examples include: 1. Temperature 2. Sugar Level 3. Water Level

5 Our body has 6 SYSTEMS to maintain homeostasis: 1. Nervous 2. Skeletal 3. Muscular 4. Excretory 5. Circulatory 6. Endocrine

6 These systems help our body with KEY PROCESSES that we need to survive Movement Excretion (elimination of waste) Response/Sensitivity Secretion (release of important chemicals) Transport ALL OF OUR BODY SYSTEMS WORK TO CARRY OUT THESE PROCESSES!

7 Maintaining Homeostasis All the chemicals of life must be kept in balance and in the range of temperature and ph to maintain homeostasis Water Macromolecules Enzymes Hormones

8 Feedback.what is it? If your body is out of balance, it will fix this through FEEDBACK. Think about it. What happens when you are cold? What happens when you are hot?

9 Feedback Loops Feedback loops regulate systems. Negative feedback loops: Result in stabilization of a system Positive feedback loops: Result in a system moving to an extreme

10 Feedback Loops The product of a process regulates the process Use feedback to maintain homeostasis Happens at all levels of organization Both Positive and Negative Does NOT mean good and bad Feedback Loops: How Nature gets Its Rhythm

11 Negative Feedback Negative Feedback accumulation of end product slows the process Brings the system back to its equilibrium position (Homeostasis) Feels like you are going back and forth

12 Body Temperature

13 Blood Glucose Level

14 Predator-Prey Relationships

15 Positive Feedback Positive Feedback accumulation of the end product speeds up its production Snowball effect

16 Herds Stampeding

17 Blood Clotting

18 Negative or Positive Feedback? If blood temperature rises too high, the brain senses the change. The brain signals the blood vessels of the skin. As these blood vessels dilate, more blood flows close to the body surface and excess heat radiates from the body. This lowers the body temperature.

19 Negative or Positive Feedback? If the blood temperature falls too low, the brain senses the change and signals are sent to the cutaneous arteries (those supplying the skin) to constrict them. Warm blood is then held deeper in the body and less heat is lost from the surface.

20 Negative or Positive Feedback? Part of the process of blood clotting is the production of an enzyme that forms the blood clot. This has a selfaccelerating effect, so that once the clotting process begins, it runs faster and faster until, ideally, bleeding stops.

21 Negative or Positive Feedback? During childbirth stretching of the uterus triggers the release of the hormone oxytocin, which stimulates uterine contractions and speeds up labor.

22 Negative or Positive Feedback? The walls of arteries stretch in the presence of high blood pressure. A signal is sent to the brain, which in turn slows down the body s heart rate. This slows the flow of blood through the arteries causing less pressure. As BP drops the arteries become less stretched and a signal is sent to speed up the heart rate.

23 Negative or Positive Feedback? A patient s body temperature was recorded over a 24- hour period; the temperature at each hour is listed in the table. TIME TEMP ( F) 12 am am am am pm pm pm pm 98.80

24 Negative or Positive Feedback? A man with heart disease has his blood pressure monitored closely. TIME BP (mmhg) 7 am am am am am noon pm 70

25 Negative or Positive Feedback? A woman is being tested for diabetes mellitus. Her blood glucose is measured over a period of time. The normal range for blood glucose is mg/dl. Blood TIME Glucose (mg/dl) hour later hours later hours later 90 4 hours later 80 5 hours later 85

26 Negative or Positive Feedback? A man with kidney problems is being watched for acid base imbalance. The normal range for blood ph is TIME ph 7 am am pm pm pm pm pm am am 7.42

Introduction to Organ Systems & Homeostasis. Packet #2

Introduction to Organ Systems & Homeostasis Packet #2 Properties of Life Order All living things maintain a high degree of order and complexity Even the smallest living thing a cell Regulate Use of Energy