A&P Quiz 1 with explained answers and diagrams

What are the four hormone classes? 17.2 ● Hormones can be divided into two major groups on the basis of the chemical structure- derived from amino acids or lipids 1. Amine Hormone- Amino acids with modified groups (norepinephrines carboxyl group is replaced with a benzene ring) 2. Peptide Hormone- Short chains of linked amino acids 3. Protein Hormone- Long chains of linked amino acids 4. Steroid Hormones- Derived from the lipid cholesterol Which are lipid soluble vs. water soluble? Why and how does this affect how they act on the cell membrane? 17.2 ● A steroid hormone directly initiates the production of proteins within a target cell. Steroid hormones easily diffuse for the cell membrane. The hormone binds to its receptor in the cytosol, forming a receptor hormone complex. The receptor hormone complex then enters the nucleus and binds to the target gene on the dna. Transcription of the gene creates a messenger rna that is translated into the desired protein within the cyto plasma. Wound healing: Intrinsic and extrinsic pathways and the role of the liver. 18.5 ● The quicker responding and more direct extrinsic pathway (also known as the tissue factor pathway) begins when damage occurs to the surrounding tissues, such as in a traumatic injury. Upon contact with blood plasma, the damaged extravascular cells, which are extrinsic to the bloodstream, release factor III (thromboplastin). Sequentially, Ca2+ then factor VII (proconvertin), which is activated by factor III, are added, forming an enzyme complex. This enzyme complex leads to activation of factor X (Stuart–Prower factor), which activates the common pathway discussed below. The events in the extrinsic pathway are completed in a matter of seconds. ● Intrinsic Pathway ● The intrinsic pathway (also known as the contact activation pathway) is longer and more complex. In this case, the factors involved are intrinsic to (present within) the bloodstream. The pathway can be prompted by damage to the tissues, resulting from internal factors such as arterial disease; however, it is most often initiated when factor XII (Hageman factor) comes into contact with foreign materials, such as when a blood sample is put into a glass test tube. Within the body, factor XII is typically activated when it encounters negatively charged molecules, such as inorganic polymers and phosphate produced earlier in the series of intrinsic pathway reactions. Factor XII sets off a series of reactions that in turn activates factor XI (antihemolytic factor C or plasma thromboplastin antecedent) then factor IX (antihemolytic factor B or plasma thromboplasmin). In the meantime, chemicals released by the platelets increase the rate of these activation reactions. Finally, factor VIII (antihemolytic factor A) from the platelets and endothelial cells combines with factor IX (antihemolytic factor B or plasma thromboplasmin) to form an enzyme complex that activates factor X (Stuart–Prower factor or thrombokinase), leading to the common pathway. The events in the intrinsic pathway are completed in a few minutes.