BIO 169 Final Exam Questions for Review Graded A 2024

What are the characteristics of an endocrine gland? - -Composed of secretory endocrine cells derived from an epithelium that is supported by a connective tissue framework. -extensive blood supply What is unique about thyroid hormone? - -it has a large concentration of iodide. -it is neither a protein or cholesterol based, they incorporate iodine as a active constituent -it has two forms (T3 (most active) & T4) How do lipid-soluble hormones exert their impact on cells? - being lipophilic the diffuse across the plasma membrane -binds to intracellular receptor in cytosol to form hormone receptor complex (hrc) -hrc binds to a particular DNA sequence in regions of chromatin within nuc. called hormone response element (hre) -resulting in transcripting mRNA -this change in protein syn. results in wither altercation in cell structure or shift in cell activity. What are the first and second messenger in the process of hormone signal transduction? - -First messenger is the ligand, (signaling hormone) -second messenger is any small, non-protein components (formation changed molecule from the 1st messeger docking.) What is a G protein? - protein named based on ability to bind guanine nucleotide. GDP=inactive GTP=active G protein is also a GTPase enzyme. How does viscosity change as a. ) RBC count changes..... b.) fluid amounts change... - A) Viscosity is inc. if the amnt of substanes (erythrocytes) inc. the amount of fluid dec. or both B) (relative concentration of solutes) ->meaning the amount of proteins or ions determines whether fluids move into or out of the plasma by osmosis *hypertonic->too much *hypotonic-> not enough What components separate out when blood is centrifuged? - Plasma 55% Buffy Coat (less than 1%) Erythrocytes 44% What characteristics about leukocytes make them unique compared to the other formed elements? - they have a nucleus! What are the characteristics of erythrocytes? - Contain hemoglobin to transport gases like oxygen Discoidal cells with a biconcave shape Have NO nucleus! What antibodies and antigens are located in type O blood? - Has NEITHER A or B Antigens Has BOTH anti A & anti B antibodies. Define intercalated discs? - connects cardiac muscle fibers to each other, prevent cardiac muscle fibers from being pulled apart during contraction and allows action potentials to travel rapidly across the muscle cells. Where are intercalted discs located? - at cell-to-cell junctions What are the functions of heart valves? - to prevent back flow of blood through the chambers List the structures, in order, in which an electrical impulse travels across the heart. - SA node--->AV node--->AV bundle---> bundle branches--->Purkinje fibers