Introduction and Homeostasis

Levels of Study

-Cell Physiology (cytology-arguably the most important level): the study of cell function *special functions of cells- cant understand the nervous system without understanding the special functions of the cell -Histology: the study of body's tissues -Organ physiology: the study of the functions of organs -System physiology: the study of the functions of organ systems -Organism physiology: the study of the function of the organism and the interactions of the organ systems *Learning about more systems you need to COMPATAMENTALIZE. For example, we learn about the nervous system and we will see how it interacts with other systems.

Basic Needs of Cells + Body

Cells, organs, systems are all performing to provide for basic needs of the body. -Nutrients (carbohydrates, proteins, fats, ect.) -Oxygen -Water -Temperature Additional Needs: -pH levels -waste levels (such as C02 levels) To maintain all of these variables: HOMEOSTASIS

Internal Environment

Example: You are a living organism. Your environment is the class room. Larger environment, campus. Larger than that Cedar City. Cells: each cell is a living organism-basic definition of life. Cell Environment: Body is made up of 3 Fluid Compartments: -Intracellular Fluid or cytoplasm: inside cell (contains different chemicals and organelles) -Interstitial Fluid: outside the cell, immediately surrounding cells -Plasma: differentiate with interstitial fluid with what is in the blood vessels; there are cells in your blood vessels (red and white blood cells with their own interstitial fluid) but the fluid outside them that is inside the blood vessel is plasma. *Interstitial Fluid and Plasma considered Extracellular Fluids. The extracellular fluid is the cells environment. That is what it interacts with and adjusts to meet needs when environment changes and effects the cell. Example: When a liver cell needs nutrients it can't go and open the fridge. Its got to get it from its environment which means some one else has to put it there. That's where the digestive system comes in. The digestive systems cells job is to get nutrients out of your GI tract and into the blood. Then the cardiovascular system cell job is to move it from the blood to the environment of the liver cells so it is there when it is needed. Liver cell can now do its job producing proteins for the rest of the body which the rest of the body uses to do their job. Its a big team with a lot of players with their own special jobs!

Basic Functions of Cells, Organs, and the Body

Necessary for life: -Maintaining Boundaries: Examples: Inside verses outside of a cell and that cell maintaining what it needs inside and what it needs outside to perform its functions. -Movement: Example: see how things move inside of cells, or movement from the inside to the outside of the cell or vice versa, or how cells move around in the body OR how cells move the body itself by skeletal muscles. -Responsiveness: Examples: (over riding function seen every where) Nervous system at a cellular level. How cell responds to its environment. Or how an organ responds to different changes in the body. Or how organ systems respond to the change of other organ systems in the body. -Obtaining Nutrients and O2: Examples: nutrients comes primarily from digestive system. Oxygen with the respiratory system. -Metabolism: Examples: skeletal muscle-important function -Excretion: getting rid of waste- renal system -Reproduction: of organisms-males and females work

Negative Feedback Mechanisms

Output of the mechanism causes variable to change in a direction OPPOSITE of its initial change. how we regulate all the different variables, keep them where we need them to be for the cells to live (nutrients, oxygen, pH, ect.) Example: Room Temperature and Blood Pressure -If blood pressure drops a mechanism kicks on such as increase heart rate which will bring it back up then beat normally after. Something goes up something goes down to maintain homeostasis.

Homeostasis

The ability of the body to maintain stable internal conditions. -equilibrium, balance what our body is doing, what are cells are constantly doing to provide for all of these needs.

Change in Physiology

The processes of physiology are always changing which make it more difficult to study. "A" does not always lead to "B" which does not always lead to "C". Since it is always changing the body must adapt.

Positive Feedback Mechanisms (much more rare in the body)

the output of the mechanism is to enhance the original stimulus or change. -if something goes higher than its normal range and is tied to a positive feedback mechanisms, that mechanisms will make the variable go even higher. With these types of mechanisms it will build and build to some big event and that event will reset the whole system. Example: Labor When the baby grows inside the uterus, the uterus walls start to stretch creating a lot of pressure. That pressure is detected by the nervous system/endocrine system and in response to that pressure a hormone is released called oxytocin. That hormone causes contractions of the uterus. While the uterus is contracting it is building more pressure so that releases more oxytocin which causes more contractions and so on until the baby is born. That big event resets the system.

Anatomy

the study of the body's structure or parts Together: known as form (anatomy) and function (physiology)

Physiology

the study of the function of living organisms "how things work"

Homeostatic Imbalance

when control mechanisms fail (more into pathophysiology). when negative feedback mechanisms fail. Example: the variable blood pressure gets too high. There are a number of mechanisms the body can use to lower it (heart, vessels, kidneys) but it is not enough to lower it. The initial problem (bad diet, lack of exercise) causing the high blood pressure is to great so blood pressure remains high. Can have immediate or long term effects on the body.