Anatomy Midterm Flashcards
What does the phrase “maintaining homeostasis” mean in the context of human physiology? What results from a failure of homeostasis?
Maintaining homeostasis means keeping a stable internal environment and adjusting physiological systems to meet that stable internal environment. Illness and death result from a failure of homeostasis.
List the three parts of any negative feedback mechanism in the body and describe the function that each of the three parts performs in a negative feedback mechanism.
The three parts of any negative feedback in the body are the receptors, the control center, and the effectors. The receptors detect the change or the stimulus. The receptors send that information to the control center. The control center will decide what to do and send instructions about what to do to the effectors. The effectors can be cells or organs that respond to the instructions and they will act against or may support the stimulus.
Explain how the body uses negative feedback to regulate body temperature when body temperature has risen higher than normal. In your answer, include the specific structures that correspond to the three parts listed in question #2 and describe their roles in lowering body temperature. Be sure to mention what has to happen to stop the process of lowering the body temperature.
In a negative feedback mechanism in the body, there are three parts to the process: the receptor, control center, and effector. In maintaining temperature, the receptors are the temperature sensors in the skin and hypothalamus. The receptors will detect the increase in temperature and will relay the information to the control center, the hypothalamus. The hypothalamus will send commands to the effectors such as the sweat glands and blood vessels. In response to high temperatures, the sweat glands in the skin will secrete more sweat, and the blood vessels in the skin will dilate. The sweat glands cause a cooling effect by the heat dissipating along with the sweat. In addition, the dilation of the blood vessels causes the heat to disperse through the surface of the skin. Through these two methods, the body temperature will go down.
Describe the layout of the thoracic cavity, explaining the locations of the hearts and lungs. Include the names of the specific cavities where these organs are located.
The thoracic cavity is the chest cavity which is above the diaphragm. The right and left pleural cavities each contain a lung. The mediastinum is right between the two pleural cavities and it is not a cavity but a solider material. It contains large blood vessels, esophagus, trachea, thymus, and pericardial cavity. The pericardial cavity contains the heart.
What is the function of cell junctions in general, and of gap junctions in particular? Give a specific example of a tissue in which gap junctions are important and explain why they’re important for the function of that tissue.
In general, the function of cell junctions is they attach a cell to another cell or extracellular materials. Gap junctions are when two transmembrane proteins hold together two neighboring cells. Gap junctions are important in heart muscle cells because electrical impulses travel through gap junctions to coordinate contractions.
Define the term gland, and differentiate between endocrine and exocrine glands regarding where they release their product.
Glands are a collection of epithelial cells that produce secretions. Endocrine glands secrete their products into bodily fluids and exocrine glands release secretions into ducts that open onto an epithelial surface.
List and describe the three basic components of all connective tissues, and name the embryonic connective tissue that gives rise to all other connective tissues.
The three characteristics of connective tissues are they are specialized cells, extracellular protein fibers, and ground substance. Mesenchymal cells give rise to all other connective tissues.
In the category of connective tissue proper, what distinguishes dense connective tissue from loose connective tissue?
Dense connective tissue is different from from loose connective tissue because dense connective tissue has more fibers, less ground substances, and is tightly packed with collagen or elastic fibers. Loose connective tissue has more ground substance and fewer protein fibers, and it is the “packaging material” of the body.
Distinguish between dense regular connective tissue and dense irregular connective tissue in terms of a. Structure and b function.
Dense regular connective tissue is tightly packed parallel collagen fibers. It is good for tendons and ligaments because it can withstand stresses from predictable directions. Dense irregular connective tissue is interwoven networks of collagen fibers and there are no organized patterns. It forms sheets and capsules that surround organs.
Blood vessels in an inflamed tissue undergo certain changes. Describe the two changes that affect these blood vessels and explain how these two changes result in three out of the four major signs of inflammation.
Inflammation causes blood vessels to dilate to increase blood flow and increases permeability which results in redness and warmth. The dilated blood vessels cause it to be closer to the surface thus making the skin appear red. In addition, since the blood vessels are closer to the surface, it makes the skin warm. Vessel dilation causes there to be an increased vessel permeability so more fluid and interstitial fluid diffuses into the tissue causing it to swell.
Explain the role of the integument in calcium homeostasis. The process of raising blood calcium levels involves a hormone whose origin can be traced back to the skin. Name the hormone, and name the specific parts of the skin involved in making the precursor to this hormone. Explain the role of the skin and the role of the kidneys in making this hormone. Finally, explain the role of the hormone in the process of raising the level of calcium in the blood.
The hormone is calcitriol. The specific parts of the skin involved in making the precursor to this hormone are stratum spinosum and stratum basale. The skin produces vitamin D3 when exposed to UV light and the kidneys convert vitamin D to calcitriol. Calcitrol is responsible for the absorption of calcium in the small intestine thus it can control how much calcium there is in the blood.
