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ap chapter 1


study of structure


study of functions of living organism and its parts

characteristics of life 1/2

1. Responsiveness = reaction to change (nervous system) ex. eyes dilating
2. Growth = incr. in body size, no change in shape
3. Respiration = obtaining oxygen; removing carbon dioxide; releasing energy from food; exchanging gases (not breathing)
4. Movement = change in position; motion (ex. smooth, cardiac & skeletal muscles)
5. Circulation - movement of substances in body fluids (circulatory system, lymphatic system)
6. Excretion - removal of wastes produced by metabolic reactions

characteristics of life 2/2

7. Digestion - breakdown of food substances into simpler forms (something you can use) assimulation-keep you alive (converting carbs, lipids, etc.)
8. Absorption - passage of substances through membranes and into body fluids
9. Assimilation - changing of absorbed substances into chemically different forms (carbs, lipids, etc)
10. Reproduction - production of new organisms and new cells

Levels of organization

Subatomic Particles - electrons, protons, neutrons
Atom - hydrogen atom, lithium atom
Molecule - water molecule, glucose molecule
Macromolecule - protein molecule, DNA molecule
Organelle - mitochondrion, Golgi apparatus, nucleus
Cell - muscle cell, nerve cell
Tissue -epithelium, connective,
muscle, and nerve tissue
Organ - skin, femur, heart, kidney
Organ System - skeletal system,
digestive system
Organism - human

Homeostasis - define & describe

1. Homeostasis is the relative constancy of the body's internal environment. no matter what does on around you. If you don't maintain you get sick.
2. External conditions may change dramatically
3. Internal conditions stay within a narrow range
4.Dynamic equilibrium. constantly changing
5. Illness or death results if internal conditions change to any great degree

Basic components (3)

1. Afferent (Sensory) Mechanism (receptor). measure everything in your body. Ex. = thermostat, temperature reading is afferent.
2. Integrating or Control Center (central nervous system). takes measurement & compares it. Ex. thermostat
3. Efferent (Motor) Mechanism (muscle or gland}. depending on the findings, this corrects it. Ex. either brings temp up or down.

Hypothalamus controls temp, water, autonomic, feeding

basic components (3) (SAME)

1. Afferent (Sensory) Mechanism (receptor)
-Monitors internal conditions such temperature, blood pressure, blood glucose levels
2. Integrating or Control Center (central nervous system)
-Compares sensory input to set point
Example: compare body temperature to normal (37' C)
3. Efferent (Motor) Mechanism (muscle or gland)
-Responds to attempt to return abnormal value towards set point
Example: Constriction of blood vessels in skin and inhibition of sweat glands in skin when body temperature is too low. If temperature low enough shivering occurs.

homeostasis of body temperature

1. stimulus - decrease in body temp
2. detected by thermoreceptors
3. hypothalamus detects deviation from normal
4. response-vasoconstriction in skin, no sweating, an if necessary shivers
5. body temp returns to normal
6. decrease body's response

homeostasis of body temperature

1. stimulus - decrease in body temp
2. detected by thermoreceptors
3. hypothalamus detects deviation from normal
4. response-vasodilation in skin and sweat
5. body temp returns to normal
6. decrease body's response

Feedback systems

changes the response
1. Two types: negative and positive (neg. most common)
2. Components
a. Receptor: monitors the value of some variable
b. Control center: establishes the set point
c. Effector: can change the value of the variable
3. Stimulus: deviation from normal; detected by the receptor
4. Response: produced by the effector (ex. shivering)

Negative feedback

1. Inhibitory
2. Oppose change by creating response that is opposite direction of initial disturbances
3. Most common

negative feedback systems stabilaize physiological variables. keep variables from straying
responsible for maintaining constant internal environment

Positive feedback

1. Stimulatory (continues or ramps up-pushes further & further away from homeostasis)
2. Amplifies or reinforces changes occurring
3. Least common
4. May cause disease

ex. childbirth-labor makes every contraction stronger; breast feeding=produce more milk as long as child need it; blood clotting=ramps up until the hole is plugged

Negative feedback that doesn't stop it becomes positive

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