Cell+Physiology

Cell Physiology



Image taken from: http://www.slh.wisc.edu/genetics/cell.gif

Cells are considered the basic structure and function of the body because everything in the body is made up of cells. In the illustration below it shows how the entire human body is made up of cells. Cells make up nerves, muscle, hair, etc. Cells make up tissue, which make up organs, which make up systems.



http://people.eku.edu/ritchisong/RITCHISO/301notes1.htm

In chapter 6 we learned about interactions between cells and the extracellular environment of a cell. The extracellular environment is the environment outside of cells. 67% of total body water is inside of the cells, 33% is outside the cells. We learned about active and passive transport across the plasma membrane.

Passive transport differs from active transort in that it does not involve any chemical energy. Rather, passive transport relies on the innate permeability of the cell membrane and its component proteins and lipids.

Passive transport- is the net movement of molecules an ions across a membrane from higher to lower concentration (down a concentration gradient) Three types 1. Nonpolar molecules can move by simple diffusion through the double phospholipid layers of the plasma membrane. 2. Inorganic ions and water molecules can move by a simple diffusion through protein channels in the plasma membrane 3. Small organic molecules, such as glucose, can move by facilitated diffusion through the plasma membrane using protein carries.

Active Transport- is net movement across a membrane that occurs against a concentration gradient (to the region of higher concentration) Active transports requires the expenditure of metabolic energy (ATP) and involves specific carrier proteins.

Below is an example of active transport taken from http://people.eku.edu/ritchisong/RITCHISO/301notes1.htm



Diffusion-
Non-polor compounds and small molecules diffuse through cell membranes. Cell membranes are impermeable to charged and most polar compounds. Charged ions must travel through a ion channel or has a transporter to move across the membrane. ==Osmosis is net diffusion of water across a selectively permeable membrane. Water diffuses down its concentration gradient until its concentration is equal on both sides of the membrane. Water channels (aquaporis) to facilitate osmosis. Osmotic pressure is the force that would have to be exerted to stop osmosis.==

http://people.eku.edu/ritchisong/RITCHISO/301notes1.htm

The transport of glucose from the blood across plasma membranes occurs by facilitated diffusion. Facilitated diffusion is powered by the thermal energy of the diffusion molecules and involves net transport from the side of higher to lower concentration.

Transport Across Epithelial Membranes: The transport of digestion products across the intestinal epithelium into the blood is called absorption. The transport of molecules out of the urinary filtrate back into the blood is called re-absorption.

The last thing we learned in chapter 6 was cell signaling. Cells communicate by signaling each other chemically. We learned about gap junctions, and the different types of signaling. Second messengers and G-proteins.
 * __Personal Application of information__**

This chapter was a great refresher for me. It has been a few years since Anatomy. This chapter is very applicable to me because negative and positive feedback loops are something that we apply in many of our classes. The most dominate negative feedback loop that I have the most experience with in working with people is insulin and glucose. It is a tricky and somewhat scary job to be responsible for the safety of someone that has diabetes or has to regulate their sugar intake and is doing a poor job of it. It is important to be the person to explain the importance to your clients and patients of regulating insulin and glucose to keep their body at homeostasis. This chapter did a great job of explaining it and I will be able to pass on that information to my clients.

The references that I have used for the information in my page is from the notes and textbook of our class. Human Physiology, by Stuart Ira Fox