Anatomy & Physiology I

BIO 1110- Lecture and Lab

Levels of Anatomical Organization and Homeostasis

Levels of Anatomical OrganizationA. Atoms- The smallest particles of matter that still retain the characteristics of that matter.•7 atoms essential for maintaining life

• Carbon, hydrogen, oxygen, nitrogen, phosphorus, calcium and sulfur

B. Molecule- Two or more atoms that are chemically bonded together.• Important molecules to life are DNA, glucose (blood

sugar), and water• Can be organic or inorganic• Inorganic= Does not contain carbon (ex. water)• Organic= Carbon containing (ex. glucose)

C. Cell- The basic structural and functional units of the body.D. Tissue- A group of 2 or more cells, all having similar origins and working together to perform a specific function.• 4 types of tissue in the human body• Epithelial= Covers and lines structures and cavities• Nervous= Transmits electrical information• Muscular= Moves the body and generates heat• Connective= Connects, protects and supports body

organs

E. Organ- A group of tissues working together to perform a specific function• Example= stomach What tissue type(s)?

F. Organ System- A group of organs working together to perform life functions. • Complete the organ systems chart

G. Organism- A group of organ systems working together.

IntegumentarySystem

SkeletalSystem

MuscularSystem

NervousSystem

EndocrineSystem

CardiovascularSystem

Lymphatic/ImmuneSystem

RespiratorySystem

DigestiveSystem

UrinarySystem

Reproductive System

Homeostasis• The

condition of equilibrium under which the body works its best.

• Feedback system: A cycle of events in which conditions of the body are monitored, evaluated, changed and reevaluated.– The 3 parts to a feedback system are: • receptor• control center • effector

Draw in your notes…

Figure 1.4

Feedback Loop• Receptors- Specialized cells that monitor

conditions inside and outside of the body.– Examples include thermoreceptors (detect temp

changes), baroreceptors (detect pressure changes), etc.

• Control Center- Receives information from the receptor and compares the information to the ranges set for homeostasis.– Usually the brain

• Effectors- Structures that receive information from the control centers and work to change the function of the body.

Negative Feedback

• Most common way that homeostasis is maintained in the body

• The response of the effector negates or opposes the stimulus (shuts off the original stimulus)

• Example- Controlling increased blood pressure by decreasing the heart rate.

Negative FeedbackSystem

Positive Feedback

• NOT a way to maintain homeostasis• The response of the effector reinforces or

exaggerates the stimulus• Example- Cervix stretching and oxytocin

released during childbirth

Figure 1–5

Positive FeedbackSystem