BIOS255 / BIOS 255 Exam 1 | Anatomy & Physiology III with Lab | Latest 2026–2027 Update | Questions & Verified Answers | Grade A – Chamberlain

BIOS255 / BIOS 255 Exam 1 | Anatomy & Physiology III with Lab | Latest 2026–2027 Update | Questions & Verified Answers | Grade A – Chamberlain Q: What are the two main cavities covered in lecture? Answer Dorsal and ventral Q: What is the function of the dorsal cavity and what two subdivisions does it contain? Answer Protection of the nervous system; cranial cavity and vertebral cavity Q: What is the function of the ventral cavity and what two subdivisions does it contain? Answer Encloses internal organs; Thoracic (above diaphragm) and abdominopelvic Q: What does the thoracic cavity contain? Answer Pleural cavity, mediastinum (surrounds remaining organs), and pericardial cavity Q: What does the abdominopelvic cavity contain? Answer Abdominal cavity (stomach, intestines, spleen, liver) and pelvic cavity (bladder, reproductive organs, rectum) Q: What kind of serous membrane lines the cavity wall? Answer Parietal (remember serous membranes are continuous) Q: What kind of serous membrane lines the organ it's associated with? Answer Visceral (remember serous membranes are continuous) Q: What is meant by the term "anatomical variability"? Answer It means that humans vary slightly in their anatomy. Only about 90% of all anatomical structures match the textbook Q: What are the functions of the plasma membrane? Answer Physical boundary, separates intracellular fluids from extracellular fluids, transports molecules, enzymatic activity, signal transduction using receptors, intercellular adhesion, cell-cell recognition Q: What is the structure of the plasma membrane? Answer It is a phospholipid bilayer that has embedded proteins Q: What is the difference between peripheral proteins and integral proteins in the plasma membrane? Answer Peripheral - one side Integral - both sides Q: What is the Glycocalyx and what is its function? Answer Area around the cell composed of carbohydrates; provides highly specific biological markers for cell-cell recognition Q: What are the four intracellular junctions? Answer Tight, adhering, gap and desmosomes Q: What are tight junctions? Answer (stitches) Impermeable junction that encircles apical surface, inhibits movement between cells Q: What are adhering junctions? Answer (snaps) Junctions that provide apical support, deep to tight junction, resists separation of cells, composed of lots of desmosomes Q: What are desmosomes? Answer Anchoring junction scattered along the side of cells, joins cytoskeleton of cells together Q: What are gap junctions? Answer A channel that allows chemical substances to freely pass between the cytoplasm of two cells Q: What is cytoplasm? Answer All materials contained within the cell membrane and outside of the nucleus (cytosol, inclusions, organelles), it is the location of many metabolic reactions Q: What is a cytoplasmic inclusion? Answer Temporary storage for pigments, glycogen, and lipids; not in all cells and not enclosed Q: What is the function of the smooth endoplasmic reticulum? Answer Lipid synthesis & storage, carb metabolism, detox Q: What is the function of the rough endoplasmic reticulum? Answer Synthesis of exported proteins Q: What is the function of the ribosomes? Answer Synthesizing proteins, there are free ribosomes (make proteins for inside the cell) and fixed ribosomes (make exported proteins) Q: What is the function of the golgi apparatus? Answer Modify proteins, package proteins into secretory vesicles which can become lysosomes and undergo exocytosis or the can be incorporated into the plasma membrane Q: What is the function of the lysosomes? Answer They are vesicles with enzymes that digest waste products Q: What is the function of peroxisomes? Answer Vesicles with enzymes that breakdown special harmful substances (hydrogen peroxide, fatty acids, alcohol) Q: What is the function of the mitochondria? Answer ATP synthesis; cellular respiration Q: What is the function of the centrosomes? Answer Organizes and supports microtubule growth, directs formation of mitotic spindle during mitosis Q: What is the function of the cytoskeleton and what does it contain? Answer structural support and transport; microfilaments (maintain and change cell shape), intermediate filaments (structure/strength), and microtubules (gives shape to cell) Q: What is the function of cilia? Answer Moves substances along surfaces of cells via mucus Q: What is the function of microvilli? Answer Increase surface are to aid in absorption and secretion Q: What is the function of the nucleus and what does it contain? Answer Control center of cell (instructions for protein production); nucleolus and DNA Q: What is and what is the function of the nucleolus? Answer Areas of concentrated RNA, synthesis of ribosomal subunits Q: How many pairs of chromosomes do humans have? Answer 23, 22 autosomal, 1 sex Q: What are the different levels of ploidy? Answer Diploid (somatic cells), haploid (sex cells), and aneuploid (abnormal chromosome #) Q: What is gene expression? Answer Translating information in DNA (genotype) into functioning molecules (phenotype) Q: What happens in interphase? Answer Maintenance (resting) phase, replication of organelles and DNA occurs Q: What are the phases within interphase? Answer G1 phase - cell growth, replication of organelles and production of proteins S phase - synthesis phase where DNA replicates G2 phase - centriole replication is completed, enzymes needed for cell division are synthesized Q: What happens in prophase? Answer Chromatin supercoils to form chromosomes, sister chromatids join at the centromere, microtubules begin to form and centrioles migrate, nuclear envelope dissolves Q: What happens in metaphase? Answer Chromosomes line up along equatorial plate, spindle fibers attach to centromere forming the mitotic spindle Q: What happens in anaphase? Answer Spindle fibers pull sister chromatids apart to opposite ends of the cell Q: What happens in telophase? Answer A nuclear envelope reforms around each set of chromosomes, chromosomes uncoil and mitotic spindle disappears, cleavage begins to show and cytokinesis occurs Q: What is cancer? Answer Damaged DNA that leads to uncontrollable mitosis Q: What is metastasis in regards to cancer? Answer Cancer cells escape from original site Q: How many checkpoints are there to prevent DNA damaging in interphase? Answer 4 Q: What are the four types of tissues? Answer Epithelial, connective, muscular, and nervous Q: What are the functions of epithelial tissues? Answer Physical protection from dehydration or abrasion, selective permeability, secretion of mucus, enzymes, and hormones, and sensation of touch Q: What are the characteristics of epithelial tissues? Answer Composed of polar cells: - Apical surface to outside of covered structures or inside of lined structures, lateral surface to other cells, and basal surface to CT and basement membrane - Avascular; nutrients supplied by CT - Cells bound by tight junctions and desmosomes Q: What is the function of simple squamous epithelial cells and where are they located? Answer Lines structures, provides thin barrier for rapid diffusion; alveoli in lungs, amnion, kidneys Two kinds: Endothelium: lines blood vessels, heart and lymphatic vessels Mesothelium: found in serous membranes of ventral body cavity What is the function of simple cuboidal epithelial cells and where are they located? Answer Lines cells, provides active barrier for secretion and absorption; ducts of glands, kidney tubules, ovary surface What is the function of simple columnar epithelial cells and where are they located? Answer Absorption and secretion of mucus, ciliated types: movement of mucus; lining GI tract, some ducts of excretory glands, uterine tubes and part of uterus What is the function of pseudostratified columnar epithelial cells and where are they located? Answer Secretion of mucus, movement of mucus; trachea, upper respiratory tracts and male reproductive ducts What is the function of stratified squamous epithelial cells and where are they located? Answer Protection of tissue beneath from abrasion; skin, lining oral cavity, esophagus, and vagina What is the function of transitional epithelial cells and where are they located? Answer Protects and stretches easily to hold fluid; bladder, ureters, urethra Where are stratified cuboidal and columnar epithelium located? Answer Cuboidal - sweat, mammary, salivary glands Columnar - transition between two other epithelial types, male urethra, salivary glands What are the two ways you classify glandular epithelium? Answer By morphology (unicellular, simple or compound, tubular or acinar) and by function (merocrine - releases contents via exocytosis, holocrine - cells rupture to release contents and apocrine - release apical surface) What is the function of areolar CT and what are some properties? Answer Binds & cushions organs & skin; by volume, it is mostly viscous ground substance, highly vascularized, found beneath epithelia What is the function of adipose CT and what are some properties? Answer Stores energy, cushions organs, prevents heat loss; only CT with more cells than matrix, found in hypodermic, near heart, kidneys, eyeballs, abdomen, breasts What is the function of reticular CT and what are some properties? Answer Provides framework for organs; found in liver, spleen, lymph nodes, bone marrow What is the function of dense regular CT and what are some properties? Answer Holds parts together; tightly packed collagen fibers with much strength against force in one direction, few blood vessels, makes up ligaments, tendons, and aponeuroses What is the function of dense irregular CT and what are some properties? Answer Holds parts together; fibers run in several different directions which gives it strength in many directions, found in dermis, surrounding cartilage in bone What is the function of elastic CT and what are some properties? Answer Allow stretch under force and recoil back to original strength; made up of branching elastic fibers and collagen fibers, found in vocal cords and walls of arteries What are some characteristics of cartilage? Avascular, no fibroblasts, mainly chondrocytes, chondrocytes sit in lacunae, firm gel-like extracellular matrix What is the function of hyaline cartilage and what are some properties? Flexible support; withstands stretch and compression, found in embryonic skeleton, articular cartilage, trachea, and larynx What is the function of fibrocartilage and what are some properties? Provides strength with minimal compression; many protein fibers, sparse ground substance, found in intervertebral discs and pubic symphysis What is the function of elastic cartilage and what are some properties? Extremely flexible support; lost of elastic fibers that are highly branched, found in epiglottis and external ear What is the function of blood? Transportation of nutrients, gases, and wastes; liquid matrix called plasma What is the function of bone and what is it made up of? Provides support and protection, blood cell production (hemopoiesis) and mineral storage; calcified matrix with collagen fibers What is the cutaneous membrane? Keratinized stratified squamous epithelium with dermis CT below What are mucous membranes? Lines body cavities that are connected to an external opening What are serous membranes? Lines body cavities and secretes serous fluid What are synovial membranes? Lines joint cavities and secretes synovial fluid; consists of areolar, fibrous or adipose CT What are some characteristics of skeletal muscle? Cells are: - Cylindrical and long - Multinucleated - Striated - Voluntary; contracted by somatic nervous system What are some characteristics of cardiac muscle? Cells are: - Branched and shorter than skeletal - Striated - One or two nuclei per cell - Involuntary - Attached at the ends by intercalated discs - Contain gap junctions that allow rapid passage of current between cells during each heart beat What are some characteristics of smooth muscle? Cells are: - Short and fusiform - Non-striated - One nucleus per cell - Involuntary What makes up nervous tissues and what are their functions? Neurons - detect stimuli and send nerve impulses Neuroglia - protect and support neurons What are the five periods from gamete to birth? Prenatal Period - from fertilization until birth ~ 38 weeks Zygote - fertilized cell Blastocyst - 0-2nd week; spherical multicellular structure that develops from zygote Embryo - 3-8th week, germ cell layers form, most organs and physical feature appear Fetus - 9th week-birth; growth and development of organs What is gametogenesis? Production of sperm/ovum via meiosis How many chromosomes does a zygote have when a sperm fertilizes an ovum? 46 (23 pairs) What happens in Meiosis I? Diploid parent cell produces two haploid daughter cells What happens in Meiosis II? Sister chromatids of each chromosome separate and go into different daughter cells What is sperm capacitation? Breakdown of glycoprotein coat, allows sperm to locate oocyte and break down oocyte protect layers with enzymes; sperm MUST undergo this before penetration of oocyte What happens when the sperm makes contact with the membrane of an oocyte? Sperm binds with binding receptor proteins on oocyte membrane, sperm's pronucleus enters ovum, oocyte complete meiosis II What two components are formed during pre-embryonic development and how long does it take? Trophoblasts - single, outer ring of cells from placenta Embryoblasts - Inner cell mass that will form embryonic disc 2 weeks What happens in implantation? Trophoblasts adheres to uterine wall, trophoblast cells proliferate, form 2 layers: Cytotrophoblast - inner cellular layer Syncytiotrophoblast - outer layer, cells lost plasma membrane How is the bilaminar germinal disc formed? Embryoblast differentiates into 2 layers: Hypoblast - adjacent to blastocyst cavity Epiblast - adjacent to trophoblast What are the extraembryonic membranes and when are they formed? Yolk sac, amnion, chorion; week 2 How is the yolk sac formed? Hypoblast cells form sac on ventral surface of embryo How is the amnion formed? Epiblast cells form transparent membrane filled sac with amniotic fluid What is the chorion? Outermost membrane formed by cytochondroblasts What is the placenta and what does it do? Highly vascularized organ that serves as a physical and biochemical interface between embryo and mother; exchange of nutrients, waste products, and respiratory gases, production of hormones, transmission of antibodies What happens during the embryonic period? - Gastrulation - during third week, two-layered embryonic disc becomes three-layered embryo - Cephalocaudal and lateral folding of the embryo- week 4 - Organogenesis - major organ systems formed weeks 5-8 What is the primitive streak? Raised dorsal groove that establishes longitudinal axis in gastrulation What happens in gastrulation? Epiblast cells migrate into primitive streak: - Cells displacing the hypoblast form the endoderm - Cells that migrate between epiblast and hypoblast form mesoderm - Epiblast cells remaining on dorsal side form ectoderm What does the endoderm end up turning into? Lining of organs (digestive, respiratory, urogenital) What does the mesoderm end up turning into? Muscle, bone, all other organs What does the ectoderm end up turning into? Skin, nervous system What is neurulation? Infolding of ectoderm to form the brain and spinal cord When is the fetal period and what happens during it? Week 9-birth; further development of organs, begins to look human What are the cells of the epidermis and what do they do? - Keratinocytes: most numerous; produce keratin - Melanocytes: produce brown pigment, melanin - Langerhans: macrophages, help activate immune system - Tactile (Merkel) Cells: associated with sensory nerve endings; touch receptors What is the stratum basale? Deepest epidermal layer, attached to dermis, keratinocytes undergo rapid division to regenerate superficial layers What is the stratum spinosum? Epidermal layer that is differentiated keratinocytes that are attached by desmosomes; melanin granules and langerhans cells are abundant What is the stratum granulosome? Epidermal layer that is 3-5 keratinocyte layers thick, beginning of keratinization, contains keratohyaline and lamellar granules What is the stratum lucidium? Epidermal layer in intermediate stage of keratinization, only in thick skin, 2-3 layers What is the stratum corneum? Outermost epidermal layer of keratinized cells, 20-30 layers What are the two regions of the dermis? Papillary (superficial) and Reticular (Deep) What is the papillary region of the dermis composed of? Loose, areolar, connective tissue; projects into epidermis, forms dermal papilla What is the reticular region of the dermis composed of and what is its function? Dense, irregular connective tissue; houses accessory structures What are ceruminous glands? True apocrine glands that secrete cerumen (ear wax) in ear canal What are mammary glands? Specialized sweat glands that secrete milk What are sebaceous glands' function? Secrete oil via holocrine gland; may be associated with hair shaft, lubricant of hair and skin What are the three types of hair? - Lanugo - fine, pale hair of the fetus - Vellus - fine, pale body hair found on children and adult females - Terminal - coarse, longer hair of eyebrows, scalp, axillary and pubic regions What is the lanula in nails? The white, moon-shaped region that covers blood vessels Plasma consists of water, proteins, nutrients, hormones, oxygen, carbon dioxide, electrolytes plasma is ___ percent of blood 55% buffy coat composed of white blood cells and platelets Viscosity resistance of fluid to flow osmolarity dissolved particles in the blood that cannot pass through the blood vessel wall If you need to examine antibodies against a virus in a patient, which part of the blood will you need? plasma albumin smallest and most abundant plasma protein viscosity and osmolarity what do albumins influence blood pressure, flow, and fluid balance globulins alpha, beta, gamma provide immune system functions fibrinogen help form blood clots RBCs (erythrocytes) count 4.2-6.2 million uL WBCs (leukocytes) count 5000-10,000 uL platelet count 130,000-360,000/uL A normal hematocrit is ___ of the total blood volume 37-52% The myeoblast cell line gives rise to which mature blood cells? Neutrophils and basophils Where does hematopoiesis take place in adults? red bone marrow The biconcave formed elements that lack mitochondria and a nucleus are called red blood cells Why do red blood cells have a biconcave shape? allows to carry oxygen efficiently red blood cells are formed in the red bone marrow to make an RBC you need EPO; amino acids; iron; vitamin B12 hemoglobin is made up of 2 alpha and 2 beta heme and globin iron in the center of hemoglobin helps to beind molecular oxygen hemoglobin function regulates blood flow and pressure Polycythemia excess of RBC anemia too few RBC sickle cell disease Genetic disorder in which red blood cells have abnormal hemoglobin molecules and take on an abnormal shape. where are antigens found found on surface of RBC antibodies carried in plasma blood type A antigen A and anti-B antibodies blood type B antigen B and anti-A antibodies blood type AB both antigen AB, not antibodies blood type O no antigens, anti A and B antibodies Type AB is the universal recipient (no antibodies) type O is the universal donor (no antigens) hemoglobin recycling Phagocytes break hemoglobin into components Globular proteins to amino acids Heme to biliverdin Iron breakdown and disposal of heme biliverdin bilirubin bile granulocytes neutrophils, eosinophils, basophils agranulocytes lymphocytes and monocytes neutrophils first WBC to arrive at infection most numerous WBC What do neutrophils do? engulf bacteria Eosinophils parasitic worms, inflammatory chemicals eosinophils functions fended against parasitic worm infections basophils allergic reactions, secrete histamine and heparin Basophils secrete heparin and histamine monocytes phagocytize bacteria and dead cells lymphocytes T cells and B cells important in immunity What do T cells do? attack microbes, tumor cells What do B cells do? produce antibodies Neutrophil percentage 60% lymphocyte percentage 30% monocyte percentage 8% eosinophil percentage 3% basophils percentage 1% lymphoid stem cells give rise to B and T cell lymphocytes, and natural killer cells myeloid stem cells give rise to RBC, platelets, monocytes, neutrophils, eosinophils, and basophils steps to hemostasis vascular spasm, platelet plug, coagulation vascular spasm immediate protection against blood loss constriction of a broken vessel vascular spasm causes nociceptors trigger constriction smooth muscle injury platelets release serotonin platelet plug formation platelets stick to broken vessel, degranulate, release substances positive feedback cycle until break in vessel is sealed coagulation most effective conversion of plasma protein fibrinogen into fibrin to form clot Procoagulants (clotting factors) present in plasma produced by liver extrinsic pathway occurs in seconds after outside trauma extrinsic pathway involves factor 5 and calcium intrinsic pathway takes longer, occurs within blood intrinsic pathway involves factor 5, 10, and calcium Aggulation clumping of red blood cells position of the heart slightly left of midline, deep to the sternum between ribs 2-5 apex rests above diaphragm Heart is surrounded by the pericardium visceral pericardium faces the heart parietal pericardium faces away from the heart pericardial fluid resides within the pericardium acts to reduce friction as the heart beats epicardium consists of consists of the visceral pericardium epicardium function production of pericardial fluid and reduction of friction against tissues myocardium consists of consist of the cardiac muscle myocardium function pump blood throughout body to deliver nutrients endocardium consist of epithelial layer and underlying basement membrane endocardium function provide smooth surface for blood movement protection of valves regulate contractility walls of atria are thin walls of atria function to collect blood from major veins and deliver to ventricles walls of ventricles are thick walls of ventricles function to generate enough pressure to pump blood through the pulmonary and systemic circuit what wall is the thickest left ventricular wall why is the left ventricular wall the thickest? it pumps blood to entire body Where does the right ventricle pump blood to? the lungs left ventricle great vessel left coronary artery right ventricular great vessel pulmonary artery right atrium great vessel inferior and superior vena cava tricuspid valve separates the right atrium from the right ventricle the tricuspid valve allows deoxygenated blood to flow from the right atrium to the right ventricle bicuspid valve separates the left atrium from the left ventricle the bicuspid valve allows oxygenated blood to flow from the left atrium to the left ventricle pulmonary semilunar valve separates the right ventricle from the pulmonary trunk aortic semilunar valve separates the left ventricle from aorta interventricular septum area of myocardium that separates the left and right ventricles papillary muscles are found on internal surface of ventricles and connect to the AV valves via chordae tendineae fibrous skeletal consists of high density area of connective tissue microscopic anatomy of the heart short, fat, branched is the heart uninucleate or multinucleate uninucleated is the heart striated yes Is the heart voluntary or involuntary? involuntary does the heart have intercalated discs? yes phases of contractile and auto rhythmic cardiac muscle pt 1 voltage threshold is reaches, sodium channels open and theres influx of sodium leads to rapid depolarization phases of contractile and auto rhythmic cardiac muscle pt 2 voltage gated calcium channels allows influx of calcium leads to voltage plateau prevent rapid depolarization phases of contractile and auto rhythmic cardiac muscle pt 3 the voltage gated calcium channels close, halt calcium influx, and potassium channels remain open, allow for potassium influx loss of potassium leads to repolarization, restoring membrane potential blood flow through the heart SVC, IVA, coronary sinus-- Rt atrium -- Tricuspid -- Rt ventricle -- Pulmonic SL -- pulmonary trunk -- right and left pulmonary arteries-- Lungs -- right and left pulmonary veins -- Lt atrium -- bicuspid/mitral valve -- Lt ventricle -- aortic valve -- aorta -- Body electrical conduction system of the heart SA node, AV node, Bundle of His, bundle branches, Purkinje fibers, contraction of ventricles occurs P wave represent atrial depolarization can lead to contraction of adjacent muscles PQ interval ventricular filling QRS denotes ventricular depolarization atrial repolarization occurs ST segment ventricular emptying T wave ventricular repolarization as ventricles relax changes in waves can indicate cardiac dysfunction ventricular diastole/atrial systole AV valves OPEN SV valves CLOSED ventricular systole/atrial diastole AV valves CLOSED SV valves OPEN as volume goes down pressure goes up as volume goes up pressure goes down the cardiac cycle lasts from one P wave to the beginning of another P wave equation for cardiac output CO = SV x HR equation for SV SV = EDV - ESV diastole vs systole label the electrocardiogram name the structure and whether it contains oxygenated or deoxygenated blood right atrium; deoxygenated name the structure aortic semilunar valve oxygen is carried by _______ cells. it binds to proteins called ______ that contain iron erythrocytes; hemoglobin of the formed elements, which cells are responsible for immune function, clotting, and gas transfer-in that order? leukocytes, platelets, erythrocytes what are the major functions of blood? (you must name 3) 1) plays a role in immune function 2) temp regulation 3) pH regulation 4) gas/nutrients/ waste transport 5) regulates water loss a patient has a stroke volume of 70ml/beat, a heart rate of 70 beats/min, a mean arterial pressure of 100, systolic BP of 95 and diastolic BP of 60. calculate output of this patient CO=SVxHR=70ml/beat/min=4900ml/min=4.9L/min which ions mediate the upstroke, plateau, and downstroke of a cardiac action potential. indicate the contraction phase that correlates to these events upstroke=sodium; depolarization plateau=calcium; contraction downstroke=potassium; relaxation what are the three layers of the heart? epicardium, myocardium, endocardium what is the fluid filled sac called that surrounds the heart? pericardium when red blood cells get broken down, the iron molecule is transferred from the macrophage to the liver with which transfer protein? transferrin Which wave indicates atrial depolarization? P wave what makes up this component of whole blood? serum, water, plasma proteins, nutrients, dissolved gases and electrolytes what type of white blood cell is displayed in this image eosinophils where does the breakdown of red blood cells start? in a macrophage what is the process of emigration/extravasation and what subtype of WBC's most commonly conduct it WBCs leaving vessels and migrating to external infections- neutrophils and monocytes what classifies an individual as anemic? they have reduced oxygen-carrying capacity of blood list the physical characteristics of cardiac muscle cells intercalated discs, nuclei, striations, gap junctions what is the driver of the heart conduction system? and what happens if it fails? the SA(sinoatrial node)-and if it fails the AV node takes over when valves close, what type of wave is observed on a pressure chart? the dicrotic wave what are 3 'systems' of blood circulation that we discussed in class? pulmonary system systemic system coronary system during ventricular systole, what is happening to the blood volume within the ventricle? first, there is no change-once pressure is great enough and the semilunar valves one, volume drops what 3 veins empty into the right atrium superior vena cava, inferior vena cava, coronary sinus an individual has an increase in afterload, what effect would this have on MAP an increase in afterload=decrease in SV=decrease in CO=decrease in MAP what are two unique structures the fetus heart has and not the adult heart? foramen ovale and ductus arteriosus which chamber of the heart has the thickest walls? left ventricle during the cardiac cycle, the heart experiences two isovolumetric states- when do these occur? the beginning of ventricular systole and beginning of ventricular diastole during ventricular systole, what happens to the pressure within the ventricles? it increases where do heart sounds come from? closing of valves where is the atrial repolarization located on an EKG it is masked by the QRS complex what chambers are contracting to cause the p-wave on an EKG the left and right atria what are the 5 structures of the cardiac conductive tissue? 1) SA node 2) AV node 3) bundle of his 4) left and right bundle branches 5) purkinji fibers the process of creating new red blood cells is called? erythropoiesis