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Homeostasis
affected by
controlled by
- Affected by: stress (heat, cold, disease, hormones...)
- Controlled by: Nervous system, Endocrine system, Environmental and behavioral factors
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Homeostasis
Main Components
- 1. Chemostasis- maintenance of electrolytes and pH bal.
- 2. Heomstatis- maintenance of blood flow for passage of oxygen & nutrients in and waste products out
- 3. Thermostasis- maintenance of constant internal body temp.
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Feedback systems
- Hormonal Control
- - negative feedback
- -positive feedback
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Negative Feedback
- response is opposite to the stimulus; body senses chnage and activates mechanisms to negate or reverse it
- (Blood Glucose Levels (insulun &glucagon)
- (Body Fluid Balance-antidiuretic hormone
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Positive Feedback
- repsonse reinforces the stimulus; change is amplified to promote more change.
- (childbirth--oxytocin)
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Negative Feedback System Components
- Receptor - structure that senses the change
- Control Center- (in the brain) meachanism to process info from receptor
- Effector- structure that carries out repsponse to restore homeostasis
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Organizational Levels of the Body
Atoms > Molecules > Cells > Tissues > Organs > Systems > Organisms
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Atoms
basic units of all matter
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Elements
simplest form of matter with unique chemical properties
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Molecules
- Combination of 2 or more atoms
- (Oxygen-O2)
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Cells
- smalles functional unit of life
- (over 200 types of cells in human body)
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Tissues
groups of cells performing a specific function
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4 Types of Tissues
- Epithelial - lines internal & external surfaces of body organs
- Connective - provides support, anchorage & connections for body structures
- Muscle- contains contractile fibers to enable movement
- Neural- initiates & conducts electrical signals
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Organs
groups of tissues forming a structure
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Organ Systems
groups of organs working together performing a major function
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