1. Homeostasis

2. Homeostasis
Have you ever been running on a hot day and started sweating?
Or out in the snow and started to shiver?

3. Homeostasis Sensor Stress (Stimulus) Skin Control Center Heat from sun
Homeostasis is the ability to maintain a relatively stable internal condition even though the outside world consist of a changing environment.
There are three components to the homeostatic system:
The Sensor which detects the stress.
The Control Center which receives information from the sensor and sends a message to the Effector.
The Effector which receives the message from the control center and produces the response which reestablishes homeostasis.
Sensor
Stress
(Stimulus)
Skin
Control Center
Heat from sun
Brain
Hypothalamus
Effect
(Response)
Effector
Sweat cools off body
Sweat Glands

4. Why don’t you keep sweating????
Heat receptors in the skin
Hypothalamus
Hyperthermia
Stress (Stimulus)
Control Center
Sensors
The Effect reduces the Stress and shuts down the mechanism
Increased activity of sweat glands
Perspiration evaporates cooling the skin
Increased blood flow to the skin
Effect
(Response)
Effectors

5. Negative Feedback Loop
A negative feedback loop is homestatic pathway where the response of the reaction shuts down the stimulus and therefore stops the response.

6. Positive Feedback Loop
In a Positive Feedback Loop the response increases and accelerates the stress (stimulus).
Can anyone come up with an example of when the body does this?
Stress
(Stimulus)
Sensor
Control Center
Intensifies
Effect
(Response)
Effector

7. Positive Feedback - Childbirth
Control Center
Effector
Effect
(Response)
Stress (Stimulus)
The birth of the child will bring this process to a close. Other examples of positive feedback regulation occur during milk letdown and blood clotting.
Sensor

8. Two pathways the Feedback Loops Use
Neural Pathway NERVOUS SYSTEM
Hormonal Pathway ENDOCRINE SYSTEM
Function: Monitor and control responses to internal and external stimuli.
Characteristics: Can work independently or together to maintain homeostasis.

9. ORGANS
NERVOUS SYSTEM
ENDOCRINE SYSTEM
Brain
Spinal Cord
Nerves

10. CELL UNIT Neuron Specialized cells in glands NERVOUS SYSTEM
ENDOCRINE SYSTEM
Neuron
Specialized cells in glands

11. CHEMICAL MESSENGERS Neurotransmitters Hormones NERVOUS SYSTEM
ENDOCRINE SYSTEM
Neurotransmitters
Hormones

12. SPECIALIZED COMMUNICATIONS PATHWAYS
NERVOUS SYSTEM
ENDOCRINE SYSTEM
Reflex arc
Senses
Negative and Positive Feedback Loops
Negative and Positive Feedback Loops

13. RATE OF REACTION Hundredths of a second Seconds, Minutes, Hours,Days
NERVOUS SYSTEM
ENDOCRINE SYSTEM
Hundredths of a second
Seconds, Minutes, Hours,Days

14. How does Caffeine Affect
Carlos came to school in the morning after staying up until 4 AM playing Call of Duty. He felt tired and sleepy and he was worried because he had a test in English class. Carlos could not understand how his friends could stay up all night playing Call of Duty and then coming to school and staying awake. His friend Jose advised him to buy a Cappuccino at the Conquest Coffee store; he told him it would give him a quick boost of energy. “Coffee keeps me moving, I need a t least one cup in the morning one in the afternoon and a Monster thought out the day, “said Jose. “It allows me to stay awake in class and get good grades; however, I have noticed that I also get sick more often.” Carlos took Jose’s advice and drank two cappuccinos and one Monster. During the day Carlos felt jittery, his hands were shaking and he could not sit still. He felt his heart beating faster and felt energized. He also felt that he needed to use the restroom more than usual. His friend Sylvia asked him if he was feeling ok, because he looked anxious. At the end of the day rather than waiting for his ride, Carlos felt he had enough energy to run home. At dinner, his mom noticed his hands were shaking. She asked if he felt all right. Carlos explained that he felt over stimulated.

15. List common foods and drinks that contain caffeine.
Coffee
150 ml (5 oz)
60-150
Coffee, decaf
2-5
Tea
40-80
Hot Cocoa
1-8
Chocolate Milk
225 ml
2-7
Jolt Cola
12 oz
100
Josta 58
Mountain Dew 55
Surge 51
Tab 47
Diet Coca Cola 45
Coca Cola 64
Coca Cola Classic 23 46
RC Cola 34
Dr. Pepper 61
Mello Yellow 35
Mr. Pibb 27
Pepsi Cola 43
Cherry Coca-Cola
8 oz
7-Up
Mug Root Beer
Sprite
Ben/Jerry No Fat Coffee Fudge Froz. Yog. 85
Starbucks Coffee Ice Cream
40-60
Dannon Coffee Yogurt 45
Chocolate Bar
3-63
Chunky Bar
11.6
100 Grand Bar
11.2
Nestle Crunch Bar 10
Krackel Bar
8.5
Peanut Butter Cup
5.6
Kit Kat Bar 5
Mr. Goodbar
Raisinets
2.5
Butterfinger Bar
2.4
Baby Ruth Bar
Special Dark Sweet Chocolate Bar 31
Chocolate Brownie 8
Chocolate Chip Cookie
3-5
Chocolate Ice Cream
2-5
Milk Chocolate
1-15
Bittersweet Chocolate
5-35 2
After Eight Mint
1.6
Jell-O Pudding Pop Chocolate

16. What parts of the body does caffeine affect?

17. How were these body parts affected?

18. What actually happened?.