Download - Bio 348 Human Anatomy & Physiology Janice Lapsansky BI 305 Email: [email protected] Phone: x7337
Bio 348 Human Anatomy & Bio 348 Human Anatomy & PhysiologyPhysiology
Janice LapsanskyBI 305
Email: [email protected] Phone: x7337
Levels of Organization• Chemical• Cellular• Tissue• Organs• Organ System• Organism
Overarching Themes(How do we know something is alive?)
Living things are …• composed of a single cell or a group of cells• AT LEAST physical and chemical machines• respond to short term changes in their
environment• grow and reproduce• adapt to long term changes in their environment
through natural selection
For a review of the chemistry of life, and cell structure and function, study the slide sets posted on the course web page.
The Boundary Organ Concept
Homeostasis of Body Fluids
• Separation of fluid compartments– intracellular fluid (ICF) = within cells– extracellular fluid (ECF) = outside cells
• intercellular fluid = tissue fluid = interstitial fluid
• plasma = fluid portion of blood, part of ECF
• Composition of fluids change as substances move between compartments– nutrients, oxygen, ions and wastes move in both
directions across capillary walls
Practice these terms! Always confusing!
Differential Distribution of Solutes in the ICF and ECF
An estimated ___ % of cytoplasmic ATP is used to run the Na-K pump in most human cells.
How is this (homeostasis) controlled?
Components of Feedback Loop
• Receptor – monitors a controlled condition
• Control center
– determines next action
• Effector– receives directions from the
control center– produces a response that
changes the controlled condition
Eg. Homeostasis of Blood Pressure• Pressure receptors in walls of certain
arteries detect an increase in BP– Blood Pressure = hydrostatic pressure;
the force of blood on walls of vessels
• Brain receives input and signals heart and blood vessels
• Heart rate slows and arterioles dilate (increase in diameter)
• BP returns to normal
Eg.Positive Feedback during Childbirth• Stretch receptors in walls of
uterus send signals to the brain
• Brain releases hormone (oxytocin) into bloodstream
• Uterine smooth muscle contracts more forcefully
• More stretch, more hormone, more contraction etc.
• Cycle ends with birth of the baby & decrease in stretch