Levels of Organization
•Life is built on successive levels ofincreasing complexity:
•Chemical (or Molecular)
•Cellular
•Tissue
•Organ
•Organ System
•Organism
Organism
Level
Integumentary
Skeletal
Muscular
Nervous
Endocrine
Cardiovascular
Lymphatic
Respiratory
Digestive
Urinary
Reproductive
Organ
Level
The
heart
Cardiac
muscle
tissue
Tissue Level
Cellular Level
Heart
muscle
cell
Protein filaments
Complex protein
molecule
Atoms in
combination
Chemical or
Molecular Level
Organ
System Level
Overview of Organ Systems
•The human body is arranged in 11organ systems:
•Integumentary
•Skeletal
•Muscular
•Nervous
•Endocrine
•Cardiovascular
•Lymphatic
•Respiratory
•Digestive
•Urinary
•Reproductive
01_01
The Integumentary System
Figure 1-2(a)
01_02aOrgSysIntegmentary_L
The Skeletal System
01_02b-OrgSysSkeletal_L
Figure 1-2(b)
The Muscular System
Figure 1-2(c)
01_02cOrgSysMuscular_L
The Nervous System
Figure 1-2(d)
01_02dOrgSysNervous_L
The Endocrine System
Figure 1-2(e)
01_02eOrgSysEndocrine_L
The Cardiovascular System
Figure 1-2(f)
01_02fOrgSysCardiovasclr_L
The Lymphatic System
Figure 1-2(g)
01_02gOrgSysLymphatic_L
The Respiratory System
Figure 1-2(h)
01_02hOrgSysRespiratory_L
The Digestive System
Figure 1-2(i)
01_02iOrgSysDigestive_L
The Urinary System
Figure 1-2(j)
01_02jOrgSysUrinary_L
Male Reproductive System
Figure 1-2(k)
01_02kOrgSysMaleReprod_L
Female Reproductive System
Figure 1-2(l)
01_02lOrgSysFemaleReprod_L
Introduction to Organ Systems
•The body can be divided into 11 organsystems, but all work together and theboundaries between them aren’tabsolute.
Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings
Homeostatic Regulation
•Homeostasis
•Maintains stable internal conditions
•Temperature
•Ionic concentrations
•Blood sugar levels, etc.
•Utilizes negative feedback mechanisms
Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings
Homeostatic Regulation
•Regulation depends on:
•Receptor sensitive to a particular stimulus
•Effector that affects the same stimulus
Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings
RECEPTOR
Thermometer
STIMULUS:
Room temperature
rises
Normal
condition
disturbed
HOMEOSTASIS
Normal
room
temperature
RESPONSE:
Room temperature
drops
Normal
condition
restored
EFFECTOR
Air conditioner
turns on
Sends
commands
to
Information
affects
CONTROL CENTER
(Thermostat)
20o
30o
40o
Homeostatic Regulation
•Negative Feedback:
•Variation outside normal limits triggers automaticcorrective response
•Response negates disturbance
RECEPTOR
Body’s
temperature
sensors
STIMULUS
Body temperature
rises above 37.2oC
(99oF)
RESPONSE
Increased blood flow
to skin
Increased sweating
Stimulus removed
Homeostasis restored
Control
mechanism
when body
temperature
rises
EFFECTOR
Blood vessels
and sweat
glands in skin
Negative
feedback
Sends
commands
to
Information
affects
Information
affects
CONTROL
CENTER
Thermoregulatory
center in brain
Sends
commands
to
EFFECTOR
Blood vessels
and sweat glands
in skin
Skeletal muscles
Negative
feedback
Control
mechanism
when body
temperature
falls
RECEPTOR
Body’s
temperature
sensors
STIMULUS
Body temperature
falls below 37.2oC
(99oF)
RESPONSE
Decreased blood flow
to skin
Decreased sweating
Shivering
Stimulus removed
Homeostasis restored
Homeostatic Regulation
•Positive Feedback:
•Stimulus produces response that reinforces thestimulus
•Response rapidly completes critical process
Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings
01_05PositiveFeedback_L
Homeostatic Regulation
•Homeostasis and Disease
•Failure of homeostatic regulation
•Symptoms appear
•Organ system malfunction
Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings