Health Science

Guide for Final Exam
Scientific Method
* Observation
* Gathered through senses
* Noticing something in the natural world
* Hypothesis
* Suggested solution to the problem
* Must be testable and predict an outcome
* Experiment
* The procedure to test a hypothesis
* Variables
* Dependent variable
* The ones that change dueto the independent variable
* Control variable
* Used for comparison.
* Experimental variable (independent variable)
* Only one
* Data Collection
* Quantitative or qualitative.
* The results to the experiment
* Organized in charts, diagrams, tables, etc.
* Conclusion
* Answer to the hypothesis based on theexperiment
* Retest
* Verify results

Homeostasis
* The maintenance of a steady state (optimum level for body functions) in an organism despite changes in the environment
* A system in homeostasis needs:
* Sensors – Detect changes in internal environment
* Comparator – Fixes the set point
* Set point – The optimum condition to function better
* Effectors –Bring the system back to the set point
* Feedback control – Negative feedback to avoid over-compensating
* Communication system – Fit the different parts together
*

Sensor
Perturbation in the internal environment
Return to normal internal environment
Effector
Comparator

Sensor
Perturbation in the internal environment
Return to normal internal environmentEffector
Comparator
Endocrine – Based upon hormones
* Nervous – Based upon nerve impulses

Sensor

Negative feedback

Sensor

Negative feedback

* It controls:
* Temperature
* Heat is lost faster in larger surfaces
* Warming up
* Vasoconstriction: Capillaries are shut off so that most of the blood remains together and keep theheat inside the body.
* Piloerection: Skin hair stands up and traps an air layer that is warmed up by your skin.
* Cooling down
* Sweating: Looses heat from skin, evaporating liquid.
* Vasodilation: Capillaries near the skin are filled with blood so that heat is lost easier.
* Water levels
* Kidneys – Through urea(Liver)
* Glucose concentration
* Pancreas
* Insulin and Glucagon

Natural History of Disease
* The relationship between coordinated events that derive from the interrelation of a human being and its environment
* An illness requires
* Suitable environment
* Host
* Agent (Pathogens)
* Biological – Viruses, bacteria, fungi, etc.* Physical – Environmental. Heat, cold, radiation, noise
* Chemical – Exogen or endogen.
* Mechanic – Weapons, falls, accidents.
* Psychological – Emotional instability.
* Natural course of infirmity – The development of a disease without any medical intervention
* Pre-pathogenic period – People are healthy. There is no disease.
* Pathogenicperiod – Starts as the infection is installed or any tissue is affected, even without any symptom
* Sub-clinic stage – Incubation period. Changing the atmosphere.
* Clinic stage – First manifestations of the disease.
* Stages of a disease
* First – Unspecific signs and symptoms
* Second – Specific symptoms related directly to a pathogen
* Third –Chronicity. Symptoms last longer than expected
* Fourth stage – Complications. It begins to affect other tissues or organs
* Fifth – Sequels. Permanent alternations or incapacities
* Sixth – Death.
* Levels of prevention
* Primary – Pre-pathogenic period
* Health promotion
* Specific protection – vaccines, diagnosis, etc.
* Secondary –...