Review questions for chapter 1 human physiology (Sherwood book) Flashcards
What is the role of cells being organized into tissues?
Tissues are defined as an aggregate of cells that have similar structure and specialized function. These tissues can achieve a specific function as a part of an organ.
What is the role of epithelial tissue?
Cells that specialize in exchange of materials between the cell and its environment. Any substance leaving or entering the body must cross an epithelial barrier.
What are some chemicals that are important constituents in the body?
Oxygen, as a final electron acceptor or as part of glucose, a carb. Nitrogen as part of nucleic acids or proteins, hydrogen as a proton gradient, sodium as a gradient for channels, etc..
Give some examples of organs functioning together.
Bone marrow makes blood cells, B lymphocyte, works with immune system and associate lymphoid organs, nervous system controls much of this.
What is homeostasis?
The ability of a cell or organism to regulate its internal environment within a physiological range in response to a varied external environment.
What are some examples of homeostasis that the body maintains?
If the body is cold, vaso-restriction can occur, shivering, to keep the body at the correct temperature.
Why is it bad to lose homeostatic balance?
The components of the body work best within a certain physiological range and disruption of this, or lack of homeostatic balance, can lead to impairment or death.
What is a feedback loop and how does it maintain homeostasis?
A feedback loop is a phenomenon in which a response is made after a change has been detected. The stimulus will then loop through the sensor, control centre and effector until the homeostatic balance is regained.
What is the difference between positive feedback and negative feedback? Give examples for both.
Negative feedback: A change in a homeostatically controlled factor triggers a response that seeks to maintain homeostasis by moving the factor in the opposite direction of its initial change.
Positive feedback: The output enhances a change so that the controlled factor continues to move in the direction of the initial change.
What are the main body fluid compartments?
The intracellular fluid and extracellular fluid. The intracellular fluid is contained within all body cells. The fluid outside the cells is called the ECF and is made up of both plasma, the fluid portion of the blood and interstitial fluid, which surrounds and bathes the cells.
How are the main body fluid compartments relevant to homeostasis?
Materials are thoroughly mixed and exchanged between the plasma and the interstitial fluid across the capillaries, the smallest and thinnest of the blood vessels. Wastes produced from the cells are extruded into the interstitial fluid picked up by the plasma, and transported to the organs that specialize in eliminating wastes. This way homeostatic equilibrium with the external environment can be reached.
How do relative ion concentrations differ between the extracellular and intracellular compartments?
The extrcellular fluid has a higher concentration of positively sodium, and chloride, and less potassium. The intracellular fluid has more potassium and less chlorine and sodium. This is because the plasma membrane allows for gradients to push out the sodium and chloride and let potassium enter, to counter the innate negative charge of the proteins and other metabolites.
Why would one type of epithelial tissue be more useful than another in different places in the body?
Depending on the specialized function generally.
Give examples of where certain epithelia may occur.
Glands are pertinent in the pancreas as part of the endocrine system or as secretion glands in the stomach, epithelial sheets are pertinent as the skin barrier,
