Anatomy and Physiology- Assignment #1

1. The maintenance of body temperature and the birth of a baby are two functions that are regulated by feedback loops. Explain the different feedback loops that regulate each process.

The maintenance of body temperature is a negative feedback loop because it is initiated by outside forces, such as exposure to temperature changes. The external temperature surrounding the body will cause the body’s own temperature to either increase or decrease, dependent on the sensory communication that occurs between the skin sensors and the brain. The body will then send messages from the brain (integrator) to the system that will act as the primary resource for maintaining homeostasis (effector), such as muscle tissue to encourage shivering to help raise the body temperature, or the sweat glands in the skin to help lower the body temperature.

The birth of a baby is a positive feedback loop because the stimulation and process of this loop starts internally, in this case, with the impending arrival of the baby. The chemical reactions that occur in the body and change of hormones constantly keep the integrator in the loop as far as ‘how far along’ the fetal development is. The same holds true when the baby is full term and other hormones and events start to take place which initiate the process of labour and expulsion of the baby. Excellent answer

2. If a person complained of pain in the epigastric region, what organs could be involved?

Pain felt in the epigastric region could possibly include the diaphragm, the liver, stomach and portions of the small intestine. Correct

3. Name a structure that is:

a. inferior to the heart: the diaphragm

b. superior to the heart: the aortic arch

c. anterior to the heart: the sternum

d. posterior to the heart: the thoracic vertebrae

e. and lateral to the heart: the right and left lungs Correct

4. Give the function of the following organelles:

a. Ribosome

Ribosomes are known as the protein factories of the cell. They are responsible for the production of protein and enzymes utilized within the cell for other functions. They appear within the cell in the cytoplasm or in the Endoplasmic Reticulum. They are tiny units that are made up of two separate units constructed primarily of Ribosomal RNA or (rRNA).

b. Golgi apparatus

The Golgi apparatus exists inside the cell in close proximity to the nucleus. It appears to be a series of stacked, flattened sacs. Their role is to accept tiny sacs filled with new proteins, produced by the smooth ER, and absorb them into their structure. Once inside, these proteins and other substances are mixed together with the contents within the Golgi apparatus, in a folding manner, then they are packaged into new little sacs and sent out of the apparatus and towards the plasma membrane, where they are eventually released and open their contents into the surrounding interstitial fluid surrounding the cell.

c. mitochondria

The mitochondria are the power houses of the cells, and are composed of two membranous sacs that are situated one inside the other. The mitochondria are responsible for the process of aerobic or cellular respiration: tiny enzymes found within the walls of the mitochondria, help to break down glucose and other nutrients. This breakdown process produces large amounts of energy, which is then used for cellular activity. The mitochondrion also has its own DNA, known as mitochondrial chromosome.

d. lysosome

Lysosomes are organelles within the cell that are membranous in nature. They look like small sacs when they are active, containing enzymes that can digest food components and other substances. They help to protect cells against destructive molecules and microbes. This process occurs through the ability of the lysosome to undergo phagocytosis.

e. centrioles

Centrioles play a role in cell division. There is a pair of two in each cell in the body. They resemble a rod-shaped structure that is composed of tiny tubules. They aid in the formation of the spindle that forms during mitosis in cell division. Correct

5. Give the function of the nucleus and nucleolus.

The nucleus is the control center for the cell. It controls every action of all the organelles that exist within the confines of the plasma membrane, as well as the complex process of cell reproduction. The nucleolus is found within the nucleus, located centrally. This structure is made up of dense formations of nuclear matter that plays a critical role in the formation of proteins. Through this process, the nucleolus programs the formation of ribosomes, within the confines of the nucleus. These ribosomes then migrate through the nuclear membrane and out into the cytoplasm where they actively produce proteins. Correct

6. Compare and contrast tissue repair in:

a. epithelial

Epithelial tissue has the greatest capacity to regenerate, along with connective tissue. When an injury occurs to the epithelial tissue, cells immediately begin to divide to produce cells that will fill in the gap left behind, once the phagocytic cells remove the dead or damaged cell from its location.

b. connective

Connective tissue also has the ability to regenerate quickly. Collagen producing cells become activated after injury, and quickly fill in the gap left after the process of phagocytosis occurs, by filling the area with a mass of dense fibrous tissue. If the damage is minimal, this mass can eventually be replaced with normal tissue. Extensive damage will sometimes result in the large dense mass being left there to produce a scar.

c. muscle

Muscle tissue has the ability to repair itself after damage. The process begins when tears within the muscle tissue are detected: surrounding cells then undergo cell division or regeneration and the damage is replaced with new cells. This is a process which is utilized for muscle growth in bodybuilding. By working out, the muscles undergo constant, slight damage, which in turn causes regeneration and hypertrophy of the muscle cells, resulting in `growth`.

d. nervous tissue

Nerve tissue has limited capacity to regenerate tissue after it has been damaged. Usually, only nerve tissue that resides outside of the brain or spinal cord has a capacity to heal, but usually very slowly, and only under specific circumstances, such as only when certain neuroglia cells are present to start the regeneration process. Any damage to the neurons in the brain or spinal cord is usually permanent. Recent research shows the discovery of important nerve growth factors that look promising in the future of treating damage in spinal cords and brain. Correct

Excellent work.

Just remember to include your sources of information (references) on every assignment. Sherri