Chapter 1: The Human Body: An Orientation

What is the principle of complementarity?

what a structure can do depends on its specific form.  In other words, STRUCTURE DETERMINES FUNCTION.

What are the necessary life functions?

Maintaining boundaries: cell membrane, integumentary system

Movement: activities promoted by the muscular system

Responsiveness (irritability): sense changes and respond to them

Digestion: breakdown of ingested food into simple molecules for absorption

Metabolism: all chemical reactions within body cells. Catabolism: breakdown into simpler substances, Anabolism: synthesis of more complex substances from simple ones. 

Excretion: removing wastes        

Reproduction: creating new daughter cells or offspring

Growth: increase in size or cell number

What is the organization of life?

chemicals (atoms, molecules), cells, tissues, organs, organ systems, organisms

What is are the organ systems?

integumentary, skeletal, muscular, nervous, endocrine, cardiovascular, lymphatic/immunity, respiratory, digestive, urinary, reproductive.

What is the dorsal body cavity?

• Cranial: contains brain​

• Spinal: contains spine​

What is the ventral body cavity?

• Thoracic: contains lungs and heart, bounded posteriorly by diaphragm.​

• Abdominal: contains digestive organs, spleen​

• Pelvic: contains urinary bladder, reproductive organs, some digestive organ

What is homeostasis?

• maintain relatively stable internal conditions while external conditions continuously changing

• dynamic equilibrium, where internal conditions vary, but always within relatively narrow limit

• Variables controlled

  • involves a stimulus, receptor, a control center and an effector.

• (ex. Blood pH range is 7.35-7.45 but the ideal would be 7.4).

What is negative feedback?

• Most homeostatic controlled by this

• output shuts off  original effect of the stimulus or reduces its intensity

• mechanisms cause variable to change in a direction opposite to that of the initial change, returning it to its “ideal” value

  • thermostat.  Ex. blood glucose levels.

What is positive feedback?

• result or response enhances the original stimulus = response is accelerated. 

• change that results proceeds in the same direction as the initial change. 

  • Ex. more oxytocin causes more uterine contractions that cause more oxytocin release that causes more contractions, etc.  

What is a homeostatic imbalance?

result in disease or aging, due to the body’s inability to maintain a stable environment.