Flashcards in Physiology 1, 2 and 3 - Intro, membrane, membrane transport Deck (58)
Group of cells with similar structure and specialise function
2 or more types of primary tissues that function together to perform a particular function(s)
groups of organs that perform related functions and work together to achieve a common goal(s)
Stable internal environment (maintenance of steady states within our bodies by co-ordinated physiological mechanisms)
In order to maintain homeostasis, what just a control system do?
Sense deviations from normalIntegrate this info. with other relevant info.Make appropriate adjustments in order to restore a controlled variable to its desired value
2 classes of control systems and explanation
Intrinsic control (local controls that are inherent in an organ)Extrinsic controls (regulatory mechanism initiated outside an organ - this is accomplished by nervous and endocrine systems)
Feedforward - responses made in anticipation of a change - usually act in combination with negative feedback)Feedback - response made after a change has been detected
Negative feedback?Positive feedback?
Negative - opposes initial changePositive - amplifies initial change
Components of a negative feedback system
Sensor, control centre (compared sensor's input with a set point), effectors
Example of positive feedback
Uterine contractions during labour become increasingly stronger until birth of baby
What are the major components of a cell membrane? (3)
Mostly lipids (phospholipids and cholesterol) and proteins (plus small amounts of carbohydrates)
How do you describe the appearance of the plasma membrane through an electron microscope?
What are the 2 main parts of a phospholipid? Charged? hydrophilic or hydrophobic?
Head (negatively charged, polar, hydrophilic)Tail (uncharged, nonpolar, hydrophobic)
What makes up the lipid bilayer of the cell membrane?
The lipid bilayer is rigid. True or false?
False - it is fluid
What is the purpose of having cholesterol interspersed in the phospholipid bilayer?
To prevent the phospholipids sticking together (contributes to the fluidity and stability of the membrane)
What word describes proteins embedded in the lipid e.g. receptors?
What word described proteins that extend through the membrane e.g. transporters, channels?
What word describes proteins that do not penetrate the membrane (most commonly intracellular) e.g. receptor-associated enzymes?
What are short carbohydrate chains found on the membrane often bound to?What is the name for the layer formed by the membrane carbohydrates which coat the surface of the cell ("the sugar coating")?
Usually membrane proteins (glycoproteins) and to a lesser extent lipids (glycolipids)Glycocalyx
What are the 3 important functions of the lipid bilayer?
It forms the basic structure of the membraneIts hydrophobic interior serves as a barrierIt is responsible for the fluidity of the membrane (enables the cell to change shape)
What type of membrane proteins are located on the inner membrane surface and interact with secretariat vesicles leading to exocytosis of the vesicle contents?
What is an example of a cell adhesion molecule that helps hold cells within tissue together?
What do the short carbohydrate chains on the outer surface act as?
Self-identity markers that enable cells to identify and interact with one another
Role of carbohydrate chains on cell surface in tissue growth?
Makes sure cells do not overgrow their own territory
What are the 3 types of specialised cell junctions?
DesmosomesTight junctionsGap junctions
What are desmosomes?
Adhering junctions that anchor cells together, especially in tissues subject to stretching e.g. skin
What are tight junctions?
Join the lateral edges of epithelial cells near their lumens (apical) membranes (tight or leaky)
What are gap junctions?
Communicating junctions that allow the movement of charge carrying ions and small molecules between 2 adjacent cells