Homeostasis of Multi-cellular Organisms

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Homeostasis of Multi-cellular Organisms

• Homeostasis is the process of maintaining a
  constant internal environment despite changing
  external conditions

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• Ensures that the organs of the body operate
  within their normal limits, thereby working
  efficiently
• Based on a feedback system
• Information is sent to a control center which
  directs the organ to react accordingly

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Two major control centers

• Brain
• Glands of the endocrine system

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Factors homeostasis regulates in Humans

• 1. Temperature
• 2. Heart rate
• 3. Respiratory rate
• 4. Blood pressure
• 5. Water balance
• 6. Blood sugar levels
• 7. Detoxification

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Summary
Activity Organs involved Center of Control
Temperature Skin Hypothalamus
Heart rate Heart Medulla oblongata
Respiration rate Ribs diaphragm Medulla oblongata
Blood Pressure Heart and arteries Medulla oblongata controls -cardiac output -arteriole resistance

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Activity Organs involved Center of Control
Detoxification Liver Liver Removes harmful substances from the blood and inactivates them, returning them to the blood to be removed by the kidneys
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Activity Organs involved Center of Control
Blood Pressure Kidneys Hypothalamus directs the pituitary gland of the endocrine system to control water levels in the blood
Water Balance Kidneys As above
Blood sugar levels Pancrease Islets of Langerhans control sugar levels 1. Insulin reduces blood sugar levels 2. Glucagon increases blood sugar levels
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Homeostasis and the NS

• The nervous system monitors and controls almost
  every organ system through a series of positive
  and negative feedback loops.
• The Central Nervous System (CNS) includes the
  brain and spinal cord.
• The Peripheral Nervous System (PNS) connects the
  CNS to other parts of the body, and is composed
  of nerves (bundles of neurons).

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Structure of the BrainGo to

• http//northernrockiesneurosurgeons.com/brain.htm
  
• Use the information on this site to label the
  parts of the brain

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