BIO 121 Module 6 Exam Essentials in Nutrition Questions and Answers (LATEST UPDATE) Portage Learning

BIO 121 Module 6 Exam Essentials in Nutrition Questions and Answers (LATEST UPDATE) Portage Learning What is the function of the pericardium? mediastinum. It protects and confines the heart within the What are the two components of the pericardium? The superficial fibrous pericardium and the deeper serous pericardium. What is the purpose of the serous fluid in the pericardial cavity? serous pericardium to reduce friction as the heart moves. Which layer of the heart is responsible for its pumping action? composed of cardiac muscle tissue. What is the endocardium composed of? It lubricates the layers of the The myocardium, which is A layer of endothelium with an overlying thin layer of connective tissue. Why is the endocardium smooth? chambers. To reduce friction as blood passes through the heart What is the difference between the pulmonary and systemic pumps? The pulmonary pump sends blood to the lungs, while the systemic pump delivers blood to and from the rest of the body. Which structure acts as the natural pacemaker of the heart? The SA node. Why is there a delay in the electrical impulse at the AV node? to fill with blood before contracting. To allow the ventricles time What is the pathway of the electrical impulse after leaving the AV node? It travels down the Bundle of His, splits into left and right bundle branches, and spreads through the Purkinje fibres. What does the P wave on an ECG represent? Atrial depolarisation, which leads to atrial systole. What does the PR interval represent? The time from the SA node firing to the AV node delay, allowing for ventricular filling. What does the QRS complex represent? ventricular systole. Ventricular depolarisation, which triggers Which electrical event is hidden by the QRS complex? Atrial repolarisation. What occurs during the ST segment of an ECG? blood is being ejected into the arteries. What does the T wave represent? The ventricles are fully depolarised and Ventricular repolarisation, marking the start of ventricular relaxation (diastole). How do electrical signals influence heart valves? Electrical signals trigger pressure changes, which in turn control the opening and closing of the heart valves. Summarize the relationship between the P wave, QRS complex, and T wave in terms of contraction. P wave = atria contract; QRS complex = ventricles contract; T wave = ventricles relax. DNA deoxyribonucleic acid Chromosome 1 long DNA molecule Gene unit of heredity Allele alternate DNA sequence version of a gene Autosome chromosome pairs 1 - 22 (same in males and females) Sex chromosome chromosome pair 23 (XX in females, XY in males) Homozygous for a gene Heterozygous for a gene Genotype the 2 alleles are identical the 2 alleles are different the two alleles for the gene (genetic makeup e.g. BB or Bb) Phenotype outcome of the physical expression of the protein due to alleles (observable properties e.g. brown eye colour) Dominant allele Recessive allele written as a capital letter written with a lower case letter Co dominance When both dominant alleles are present, both phenotypes are expressed Sex-linked When the disease allele is on the X chromosome it is sex-linked Cell division Process by which cells reproduce themselves Mitosis replaces somatic/body cells - diploid cells Meiosis forms gametes in ovaries and testes - haploid cells DNA replication timing Mitosis process outcome Nucleotide components occurs during the S phase of the cell cycle Produces identical cells (two) Phosphate group, Deoxyribose sugar, Nitrogen containing base Where is the heart located in the body? The heart lies in the mediastinum, with about two thirds of its mass to the left of the body's midline. What are the three layers of the heart wall? The epicardium (external), myocardium (middle), and endocardium (inner).