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Laura Shevy March 2001 Physiology Lab Histo Review #2 Exam: 03/14/01 1:15pm 12 hrs of video tape (Lab 6 = review) Labs 1-4: Cardiology Lab 1 Heart Layer Composition Connective Tissue Presence of Nerves Endocardium CT, endothelium, though it’s usually stripped off CT, cardiac muscle in many different orientations CT, adipose tissue. Comprises AV sulcus. FECT, elastic fibers None loose FECT with capillaries None loose irregular FECT, or dense irregular FECT with larger collagen Postganglionic Parasympathetic nn/ganglia present down to the level of AV sulcus Myocardium Epicardium AV sulcus-adipose tissue on left atrial wall. Trabecular Carnae-space within the right ventricular wall. Lined by endocardium and as such is continuous with the ventricular lumen. It is an extension of the pectinate muscles. Chamber Size of Endocardium Lumenal Surface Size of Myocardium Arrangement of Details of Myocardium Epicardium Left Atrium Thickest of all 4 chambers Smooth: no pectinate muscles or trabecular carnae Pectinate muscles exist as invaginations of myocardium, creating a rough lumenal surface Has trabecular carnae; irregular wall of lumenal surface Smooth lumenal surface Small Loose arrangement; has adipose and loose FECT Loose arrangement; has adipose and loose FECT Smooth lumenal surface Muscular part is stained red Right Atrium Still thick, but not as thick as the left atrium Right Ventricle Thinner than that of atria Left Ventricle Thinner than that of atria IV Septum Both surfaces are covered by endocardium, although it is thin because it is in between the ventricles Small Very large Wicked large! Loose FECT in between muscle fibers. Densely packed myocytes. Looks like steak. Membranous part has dense irregular FECT and stains blue Postganglionic Parasympathetics Postganglionic Parasympathetics None present because the septum is in the middle of the heart Summary of Lab 1: RA vs. LA: Right atrium has pectinate muscle RA vs. RV: Atrium has thicker endocardium and thinner myocardium; ventricle has very thick myocardium and thin endocardium RV vs. LV: Right ventricle has thinner myocardium and trabecular carnae with rough endothelial surface LA vs. LV: Atrium has thicker endocardium and thinner myocardium; ventricle has larger myocardium LV vs. IV Septum: Septum has endocardium on both sides. AV cusp: cusp that is part of the tricuspid valve (r) or mitral (l) between atrium and ventricle Septal cusp: on IV septum: membranous septum has cusp within the tricuspid valve, so it is on the right side. Lab 2 The epicardium is lined by a layer of squamous cells which comprise the mesothelium, which comprises the visceral pericardium or serous layer. The parietal pericardium is also known as the fibrous layer, and is that which is removed to reach the heart. Anulus fibrosus is the point at which the AV valve cusps originate, where there is only connective tissue and no cardiac muscle. Surfaces of Cusps (think inverse collagen rule) Surface of Cusp Presence of Elastic Fibers Collagen Blood Flow Deforming Surface Has elastic fibers Smaller collagen fibers Holding surface No elastic fibers Large collagen fibers Faces oncoming blood (for AV valve, faces atrium; has to bend more, hence the elastic fibers) Faces region of highest pressures, here the ventricles; the collagen resists the change in pressure Random Structures that Need a Home in a Chart Somewhere Structure Composition Association Chordae Tendonae Anulus Fibrosus Dense, regular FECT; covered in endocardium Dense, irregular FECT Attaches cusp to papillary muscle Attaches cusps to atrial wall During ventricular systole, the pressure in the ventricle greatly exceeds the pressure in the atrium. The AV valves prevent backflow into the atrium as they are connected to papillary muscles on the ventricular wall by chordae tendonae. When the ventricle contracts, the moderator band brings the APs to tell the papillary muscles to contract, pulling down on the chordae tendonae and thus pulling down on the AV valves. Thus, the pressure in the ventricle cannot cause the valves to evert backup into the atrium. This prevents backflow of blood. Atrium > Anulus Fibrosus > Chordae Tendonae > Papillary Muscle > Ventricular Wall Cusps Cusp/(Valve) Location How to Determine Miscellaneous Deforming/Holding Helpful Info Septal Cusp (right tricuspid valve) Anterior Cusp (right tricuspid valve) Off membranous IV Septum Elastin (D) is red; Collagen (H) is blue AV cusp Pulmonary Semilunar Appears without the vein (small cardiac vein). A(nterior) = without Off pulmonary trunk (RV) Collagen is larger on the deforming surface Covered in epicardium, why, I don’t know To determine cusps… 1. Determine side of heart 2. If it is right: it can be A, P, or S cusp. If you see marginal artery and no vein (small cardiac vein) then you have the anterior cusp, because the artery and vein don’t associate until the posterior. So if you do have a vein, it’s the posterior cusp. To be the septal cusp, you’d have to see septum. 3. If it’s left: Lab 3 Fibrous Skeleton of the Heart - origins and insertions of cardiac muscle Cardiac muscle cells are interconnected via the intercalated discs. As such, they are organized in series running down one side of the heart, where they connect to the fibrous skeleton of the heart. When the ventricles contract, each individual muscle cell shortens, and they bring the bottom (apex) of the heart upwards, closer to the AV sulcus. When the atria contract, they bring the heart downwards. Structure Composition Association Function Anulus Fibrosus (L and R) Dense, irregular FECT Between atrium and ventricle Origin of valve cusps Membranous IV Septum Dense, irregular FECT CT above muscular IV septum Root of Aorta or Pulmonary Trunk Dense, irregular FECT Part of the aorta above the ventricle and below the semilunar valve Valve Cusps Present Right Tricuspid Anterior, Posterior, Septal Anterior, Posterior Posterior, Left, Right Left Mitral Aortic Semilunar Pulmonary Electrical insulation of the heart: cardiac muscle is a good conductor bc of gap jns, so this prevents the entire excitation of the heart Origin for aortic/pulmonary cusps Anterior, Left, Right Spaces at Beginning of Large Vessels Structure Composition Information Aortic Sinus Elastic-red (muscular septum has elastic fibers; appears red) Collagen-blue (membranous has collagen; appears blue) Aorta-purple (has both) Pulmonary trunk CT; space where there is no cardiac muscle Dilatation at aorta where coronary arteries originate. It’s a space in between the semilunar cusp and the wall of the aorta. Faces holding surface of the cusp, the non-blood side. Conus Arteriosus Lab 4 - Conducting System Has epicardium, unlike aortic sinus because it is an extension of the right ventricle. Conducting vs. Working Cells Structure Function Conducting Cells Purkinje cells, etc. Working Cells Myocytes Cytoplasm Nucleus Darkening of cytoplasm is limited to periphery bc the amount of myofibrils is decreased Dark, stains red bc of proteins in cross section bc it is filled with myofibrils Centrally placed Centrally placed Nodes Nodes are individual conducting cells which are embedded in dense, irregular FECT. AP is generated in SA node, travels via conducting fibers, migrates through the myocardium and current spreads through gap junctions. The spread of the AP to the left atrium occurs via interatrial fibers and causes atrial systole. Then the AV node is excited. The bundle of His, a group of conducting cells then comes forward from the AV node and enters the membranous IV septum. The AP then divides into R and L Bundle Branches which terminate in Purkinje cells. The AP travels through these such that the muscular IV septum is the first area to contract within the ventricular. This forms a rigid point by which the walls of the heart can contract against. The second thing to contract is the papillary muscle. Only after this contracts that the AP makes its way through the Purkinje cells to the outside of the heart. Then the outer wall of the heart contracts and squeezes towards the muscular IV septum. Structure Location Structure Tissue Layers Cellular Characteristics SA Node At superior vena cava as it enters right atrium Individual conducting cells embedded in dense, irregular FECT Junction of epicardium and myocardium. AV Node In interatrial septum, just above the opening of the coronary sinus. Individual conducting cells embedded in dense, irregular FECT Junction of endocardium and myocardium Parasympathetic Ganglion Bundle of His In wall of heart muscle, probably atria? Junction of membranous A bunch of nerve cells surrounded by CT A bunch of conducting cells Epicardium Darkened at periphery and lightened in middle: hollow centers. Myofibril content is less than myocytes. Decreased staining intensity. Darkened at periphery and lightened in middle: hollow centers. Myofibril content is less than myocytes. Decreased staining intensity. Eccentrically placed nuclei and coarse Nissl Substance. Darkened at periphery and Junction of membranous and and muscular IV septa, more connected with membranous IV septum. surrounded by CT Bundle Branches Off of Bundle of His, along sides of muscular IV septum. Usually there are multiple branches. Terminations of the Purkinje Cells Bundle Branches, in the ventricular walls. Branches of above Not surrounded by or embedded in connective tissue. muscular IV septa. lightened in middle: hollow centers. Myofibril content is less than myocytes. Decreased staining intensity. NOT surrounded by CT, however. Extensions of above. Junction of endocardium and myocardium. Darkened at periphery and lightened in middle: hollow centers. Myofibril content is less than myocytes. Decreased staining intensity. Lab 5 - Vascular System (02/13/01 2nd hr.; Ch. 10) Vessel Type Tunica Intima Tunica Media Tunica Adventitia Special Features Elastic Arteries (Aorta Proper, Carotid) Medium: dense irregular FECT, with fibroblasts Small: mainly collagen (but has some elastic fibers. Dense, irregular FECT. Elastic fibers form concentric rings around the artery called elastic laminae. Muscular Arteries Small: dense, irregular FECT LARGE: smooth muscle and elastic fibers. Elastic fibers stain wavy red and are very uniform on H+E stains; stain black on the specially stained cells. LARGE: smooth muscle and very few elastic fibers. Internal elastic laminae divide tunica intima from tunica media; external elastic laminae divide tunica media from tunica adventitia. Arterioles Small: endothelial cell layer only. Medium: dense irregular FECT which becomes the fascia (loose/dense irregular FECT) that surrounds all blood vessels. Small: dense, irregular FECT, but present. Boundary is unclear. LARGEST: 9 concentric smooth muscle layers or fewer Capillaries Only layer present: endothelial cell layer. Can only accommodate one rbc. None None Post-capillary venule Only layer present: None endothelial cell layer. But can accommodate 2-3 rbcs. Endothelium only None None Medium-sized Vein Large Vein (SVC, IVC) Endothelium only LARGEST: Lymphatic Vessel Endothelium, maybe some CT on larger vessels. Have one-way valves which prevent backflow of lymph, since the pressures here are very low. Smooth muscle; Tm is asymmetric so wall thickness is not uniform. Metarteriole Endothelium? Single layer of smooth muscle, but it is discontinuous. Venule Endothelium, some CT Small: 3-4 smooth muscle cells thick Small: 5-6 smooth muscle cells thick LARGEST: fibroblasts only. LARGEST: dense irregular FECT and longitudinal smooth muscle in alternating layers. Connective tissue that blends in with outer tissues None Will be near adipose cells because they are highly vascularized. Have pericytes, contractile, pluripotent cells that do tissue repair. They are round, euchromatic, and larger than the endothelial cell itself. They are not in contact with the lumen. Pericytes on outside of the lumen. PCVs can accommodate 2 or more rbcs. Wall is not thick but lumen is. Accompany arterioles. Wall thickness varies; not uniform. Accompanies muscular artery. Internal elastic laminae present. Large vein has Longitudinal smooth muscle layer. Asymmetric tunica media because the smooth muscle is neither longitudinally nor circularly arranged. Also carry mainly wbcs, and carry NO rbcs! More leaky than discontinuous capillaries, so proteins can leak out and into lymph to return to blood supply. Have one-way valves in tunica intima to prevent backflow. Preferential pathway for shunting blood away from capillary beds. They dilate and the blood will not flow through the capillary bed. Tunica intima Lymphatics contain valves in the tunica intima Small for all vessels Tunica media Elastic fibers form concentric rings around the artery called elastic laminae in elastic arteries. Arterioles are those vessels which have 1-9 layers of vascular smooth muscle in the tunica media. Largest layer in arteries/arterioles Tunica adventitia Vasa vasorum is a blood vessel within a blood vessel and is found within the Tunica adventitia or outermost part of the Tunica media. Provides a nutrient blood supply for the outer portions of the larger blood vessels which cannot be fed by the lumen of the vessel. Nervi vasorum is a nerve found within the Tunica adventitia. Largest in veins/venules Read pp 74-78!!!! (Lab 6 was a review) Lab 7 - Respiratory, Part I Lower airways: TracheaPrimary BronchiLobar BronchiSegmental BronchiTerminal BronchiolesRespiratory BronchiolesAlveolar DuctsAlveolar SacsAlveoli Upper airways: Nasal PassagesNasopharynxOropharynxLaryngopharynxTrachea… Cartilage Elastic Fiber Type Content Overall appearance FECT type Elastic Lots of elastic fibers Fibrous Collagen Type II also, but the elastic fibers cause it to appear fibrous (NOT collagen’s fault). Hyaline Few to no elastic fibers Smooth Collagen Type II-forms fibrils but not fibers. We cannot see fibrils, so it appears smooth. Isogenous groups are groups of chondrocytes separated from one another by territorial matrices. Isogenous groups are separated from one another by interterritorial matrices. Chondrocytes synthesize and regulate the matrix (esp territorial matrix) so the interterritorial matrix is longlived and not well-regulated. Organ Epithelium Lamina Propria Submucosa Perichondrium Cartilage Special Features LarynxEpiglottis Anterior surface: Stratified squamous incompletely keratinized (lines all mucous membranes) Posterior surface: Pseudostratifed Dense, irregular FECT Capillaries, postcapillary venules Loose FECT Arterioles and Venules, some capillaries Dense, irregular FECT with glands, adipose. Covers the cartilage. Anterior surface remains stratified squamous, while posterior surface becomes pseudostratified further down LayrnxThyroid Cartilage Pseudostratified columnar Elastic cartilagecontains elastic fibers. Chondrocytes lie in lacunae which are spaces within the CT matrix. Cells shrink due to poor ability to stain the dense material. Hyaline Has glands-both Present serous and mucus, so it’s a mixed gland. Loose connective tissue. LarynxFalse Vocal Fold Pseudostratified columnar with cilia LarynxLaryngeal Ventricle Larynx-True Vocal Fold Pseudostratified columnar Trachea (below level of cricoid cartilage!) Bronchus (Primary Bronchus) stratified squamous incompletely keratinized. Ciliated. Pseudostratified with ciliated cells, basal cells, goblet cells, and brush cells. Thick basement membrane. Goblet cells secrete in response to irritants, as compared with glands which secrete constitutively. Pseudostratified columnar with cilia. Prominent basement membrane. Thin layer that is fairly vascular; dense irregular FECT small Thick-with glands and loose CT and adipose NONE. NO GLANDS EITHER! Cells, blood vessels, Exocrine glands nerves, loose FECT (secretory and NO glands. No portion). tunica muscularis. Collecting Highly cellular. ducts.Myoepith elial cells have Collecting ducts (nonciliated) and M2 receptors, main ducts (ciliated). act’d by parpasympathet ics which squeezes gland contents forward. Tunica muscularis is none formed by smooth muscle. Also has glands, nerves, mucociliary escalators. Smooth muscle is spiraling, so it lies in oblique section. Present Dense, regular FECT forms the vocal ligament dense, irregular FECT Hyaline Skeletal muscle of vocalis muscle (thyroartenoideus) Hyaline cartilagematrix appears smooth. Type II cartilage only forms fibrils, not fibers. Has isogenous groups of chondrocytes within lacunae. Goblet cells secrete mucous and are called mucociliary escalators. They do gas exchange, clean, and humidify the air. Mucus sits atop the serous solutions and traps all the bad stuff coming in. Cilia beat in the same direction, toward the pharynx. Cartilage plates, no intact c-shaped ring. Parasympathetic ganglia are found in “tunica adventitia” which is considered the layer outside the cartilage (or submucosa if there is no cartilage). Parasympathetic constricts smooth muscle and is normal mechanism of control. Simple columnar which becomes simple cuboidal. Some are ciliated, but that’s hard to see. NO GOBLET CELLS. Simple cuboidal Respiratory which becomes Bronchiole (Respiratory) simple squamous. Simple squamous Alveolar Ducts Terminal Bronchiole (Conducting) Lamina Propria before Tunica muscularis with smooth muscle. PERI NO GLANDS Tunica muscularis very thin but present. No glands None None B R O N CH None I O LA R S P A C E NO CARTILAGE Some elastic fibers allow for elastic recoil. No cartilage Associated with alveoli and as such provide for gas exchange. Interalveolar septa divide alveoli. Holes=alveolar pores. Have capillaries, pneumocytes, and macrophages (see below). None 02/28/01-Tape 6 Interlobular septa are invaginations of the outer capsule of the lung (pleura). They have the pulmonary veins; the pulmonary artery runs in the lung lobule all the way down to the alveolus. At the alveolus, there is a squamous cell and a capillary in the interalveolar septum. Within this interalveolar septum, there are three types of cells: Cell Type Nucleus Cytoplasm Location Type I Pneumocyte Type II Pneumocyte Endothelial Cell Squamous Not discernible Rounder Bulges into the lumen Squamous Not discernible Alveolar Macrophage Eccentric, bean-shaped nucleus; round large cell Granular cytoplasm filled with lysosomes. Cytoplasmic extensions connect membrane to epithelium. Deep red staining. Lots; On surface of interalveolar septum At junction of two alveolar septa (branch points) In middle of septum; in association with a capillary (look for space for rbc) Monocytes that left the lung capillary to become macrophages. Line intersitial spaces, epithelium. sticks out into lumen. Arteries associated with airways; veins in space. Lab - Kidney Structure Location Tissue Type On outside of Cortex Capsule (Gerota’s Fascia) Renal Corpuscle Cortex (cortical labyrinth) Dense, irregular FECT Contains the glomerulus, which is a capillary bed (look for endothelial cells!) + Bowman’s Capsule (which is a space surrounding the glomerulus). Loop of Henle Cortex (define cortical labyrinth) Outer Medulla Renal Papilla Inner Medulla Minor Calyx End of Inner Medulla Medullary Rays Defining Features Made up of tubules Transitional Epithelium Lies within the cup of the Minor Calyx Space at end o’inner medulla *For Iris: Minor CalyxMajor CalyxRenal PelvisUreter all have transitional epithelium* Parts of the Nephron Structure Location Epithelium Nucleus Cytoplasm Special Features Proximal Tubule Convoluted: cortical labyrinth Straight: descending limb of Loop of Henle, in medullary Ray Cortical Labyrinth- in Columnar (pyramidal) Centrally placed No basophilic staining; mitochondria cause granular staining of cytoplasm Brush Border created due to numerous microvilli. Apical surface is not clear. None Endothelial cells None Reabsorb stuff from the Peritubular Capillaries Thick Descending Limb of Loop of Henle Thin Loops Vasa Recta Thick Ascending Distal Tubule Collecting Duct (not actually part of the nephron!) between proximal and distal tubules Medullary Ray continues into outer medulla distal and proximal tubules Pyramidal-esque Inner Medulla (renal papilla) Inner Medulla Medullary Ray Cuboidal-esque Convoluted: cortical labyrinth Straight: cortical labyrinth? Medullary Ray into medulla Simple cuboidal Cuboidal, increases to columnar, increases to stratified as it goes from the cortex to the medulla. Type of Nephron Special Features Juxtamedullary Long, thin loops go all the way down into the inner medulla Very short thin loops in the inner medulla. *There are no thin loops in the outer medulla that are visibile* Cortical Squamous nuclei that bulge into lumen Squamous nuclei with thinner walls that do not bulge into the lumen. Tends to bulge into lumen Less granular staining. No brush border. Have visible junctions in between their cells that look like plasma membranes. Region Structures Present Cortical Labyrinth renal corpuscles, proximal tubules, distal tubules, peritubular capillaries. Almost no interstitial space. loop of Henle (thick descending, thick ascending), collecting duct descending limb, thick ascending limb, macula densa of cortical nephrons. THIN LIMBS HERE! descending limb, thick ascending limb of juxtamedullary nephrons. Only thin limbs, collecting ducts; Vasa recta which are associated with loop of Henle and are the blood supply of the medulla. Medullary Ray Outer Outer Medulla Inner Outer Medulla Inner Medulla *In the outer medulla, you cannot distinguish asc or desc thick loops; only the collecting ducts. This is because here the asc and desc thick loops are in transition. They are, however, distinguishable, in the medullary rays. You can always distinguish the collecting duct by its pseudo membrane appearance. Cells of the Glomerulus Structure Location Nucleus Podocyte Outside the glomerular capillary Endothelial Cell Inside the glomerular capillary Parietal Layer Cell Macula densa On outside of capsule Larger, more euchromatic Smaller, more hyperchromatic, squamous Squamous On outside of glomerulus Inside of afferent arteriole JG Cells READ pp 93-96; 74-78 Cluster of cells next to the corpuscle Secrete Renin