Anatomy & Physiology I BIO Lecture and Lab Levels of Anatomical Organization and Homeostasis

Levels of Anatomical Organization A. 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.

Integumentary System

Skeletal System

Muscular System

Nervous System

Endocrine System

Cardiovascular System

Lymphatic/Immune System

Respiratory System

Digestive System

Urinary System

Reproductive System

Homeostasis The condition of equilibrium under which the body works its best. 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 Feedback System

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 Feedback System