Documents about Cardiac Muscle

  • 5 Pages

    LEC 2 (11)

    Berkeley, MCB 58168

    Excerpt: ... MCB 136 Professor Terry Machen 2/26/09 Lecture 11 ASUC Lecture Notes Online is the only authorized note-taking service at UC Berkeley. Do not share, copy or illegally distribute (electronically or otherwise) these notes. Our student-run program depends on your individual subscription for its continued existence. These notes are copyrighted by the University of California and are for your personal use only. LECTURE Lets start by talking about cardiac muscle . Cardiac muscle cells, also called cardiocytes or cardiac myocytes, are relatively small. A typical cardiac muscle cell has a single and a centrally placed nucleus. A few may have two or more. Cardiac muscle tissue is found only in the heart. Cardiac muscle shares similarities with skeletal muscle. It has a striated appearance and similar contraction. As in skeletal muscle, action potentials trigger calcium release from the sarcoplasmic reticulum (SR) and the contraction of sarcomeres; it also increases the permeability of the sarcolemma to extracellul ...

  • 5 Pages

    Lec 2 (12)

    Berkeley, MCB 58168

    Excerpt: ... MCB 136 Professor Terry Machen 2/26/09 Lecture 12 ASUC Lecture Notes Online is the only authorized note-taking service at UC Berkeley. Do not share, copy or illegally distribute (electronically or otherwise) these notes. Our student-run program depends on your individual subscription for its continued existence. These notes are copyrighted by the University of California and are for your personal use only. LECTURE Lets start by talking about cardiac muscle . Cardiac muscle cells, also called cardiocytes or cardiac myocytes, are relatively small. A typical cardiac muscle cell has a single and a centrally placed nucleus. A few may have two or more. Cardiac muscle tissue is found only in the heart. Cardiac muscle shares similarities with skeletal muscle. It has a striated appearance and similar contraction. As in skeletal muscle, action potentials trigger calcium release from the sarcoplasmic reticulum (SR) and the contraction of sarcomeres; it also increases the permeability of the sarcolemma to extracellul ...

  • 2 Pages

    What_You_Should_Have_Gotten_Out_of_the_S

    Michigan State University, PSL 250

    Excerpt: ... What You Should Have Gotten Out of the Smooth Muscle and Cardiac Muscle Lecture or Learning Objectives for the Smooth Muscle and Cardiac Muscle Lecture Smooth muscle cells are smaller than skeletal muscle cells. Smooth muscle has myofilaments but they are not arranged the same way they are in skeletal muscle. Activation of the cross bridges (which allows myosin to bind to actin) is different in smooth muscle (compared to skelelal muscle). 1. Describe smooth muscle including the following: a. Describe location, know the examples of smooth muscle given, innervation, anatomy (including size, shape lack of striations, myofibrils, and sarcomeres). b. Describe the arrangement of myofilaments. Know differences in myofilaments of smooth muscle compared to skeletal muscle (length of myosin filament, where actin is anchored, filament orientation to the cell, i.e. diagonal). Describe the mechanism for contraction and cross bridge activation. Is troponin present? (Note: cross bridge activation means myosin can bind actin ...

  • 3 Pages

    lecture_notes_18_(ta)

    UC Davis, NPB 101

    Excerpt: ... of the AV valves and the interior base of the ventricles via papillary muscles. They prevent the AV valves from everting ( TURNING INSIDE OUT ) during the strong pressure wave that occurs during ventricular contraction (Figure 9-4). ( THEY HELP PREVENT THE VENTRICLES FROM PUMPING BLOOD BACK TO THE ATRIA. ) Connective Tissue Inside the chambers of the heart there exist four rings of dense fibrous connective tissue that surround the each of the valves of the heart. This tissue separates the atria from the ventricles and provides a fairly rigid base for attachment of the heart valves and the cardiac muscle (Figure 9-5). Heart Walls ( 1 ) Endocardium - this is a thin layer of endothelial tissue which lines the interior of each chamber. ( 2 ) Myocardium - this is the middle layer of the heart wall and is composed of cardiac muscle . The myocardial muscle fibers are arranged in interlacing bundles that form a spiral around the circumference of the heart. The cardiac muscle cells are connected end ...

  • 3 Pages

    human physiology study questions 22

    University of Iowa, INTEGRATIV 130

    Excerpt: ... Lecture 22 Study Questions Which of the following statements about the heart is correct? a) b) c) d) e) the right ventricle is responsible for pumping blood through the systemic circulation. normally the sympathetic and parasympathetic nervous systems do not influence heart rate. the pulmonary valve prevents the backflow of blood into the right ventricle. the coronary arteries branch from blood vessels coming from the lungs. the P-wave of the ECG is produced by action potentials in the AV node. Which of the following statements about cardiac muscle cells is correct? a) b) c) d) e) they have a pacemaker potential that is much slower than the pacemaker potential of sinoatrial node cells. the opening of cell membrane Ca2+ channels causes the fast rise in membrane potential at the start of an action potential excitation-contraction coupling occurs when Ca2+ binds tropomyosin. an increase in the release of Ca2+ during excitation can increase the force of contraction. a and d. Correct answers: 1. c. 2. e. ...

  • 7 Pages

    KEY-Bio416K_Exam_4_Spring_06

    University of Texas, BIO 416K

    Excerpt: ... osphatase activated 6. actin-myosin cross bridge formation a. 2-3-4-1-6-5 b. 3-2-1-4-5-6 c. 3-2-4-1-6-5 d. 4-1-3-2-6-5 e. 3-2-1-4-6-5 17. All of the following are believed to contribute to muscle fatigue EXCEPT: a. Lack of ATP b. Depletion of glycogen c. Increased levels of inorganic phosphate d. Lack of acetylcholine + 2+ e. A shift in K levels which lead to decreased Ca release 18. A package insert for a drug states "this medicine is a beta adrenergic receptor agonist used to treat symptoms of asthma, emphysema and other breathing conditions." What type(s) of muscle fibers respond to this medication? a. Skeletal muscle fibers b. Smooth muscle fibers c. Cardiac muscle fibers d. B and C are correct e. A, B and C are correct 19. The importance of the plateau phase of the action potential of myocardial cells is in _. a. Preventing overstretching of the contractile cells b. Enhancing the efficiency of oxygen use by the cells c. Preventing tetanus 2+ d. Regulating Ca availability to the cel ...

  • 4 Pages

    cardiac1

    Penn State, BIOL 141

    Excerpt: ... Lecture Outline March 7, 2008 Cardiovascular System I Anatomy of heart Layers of the heart wall epicardium myocardium endocardium (endothelium) Blood flow Two circuits: 1. pulmonary 2. systemic Heart Valves: atrioventricular valves: tricuspid (R), bicuspid (L) semilunar valves: pulmonary & aortic Coronary circulation Biology 141: Physiology 1 Lecture Outline Cardiac muscle and the conduction system Cardiac muscle cells Cardiac muscle AP phase 0: Na+ channels open phase 1: Na+ channels close; fast K+ channels open -early partial repolarization phase 2: plateau phase-, K+ channels close; Ca2+ channels open phase 3: Ca2+ channels close; slow K+ channels open phase 4: resting potential Effective refractory period (ERP) limits the frequency of action potentials (and therefore contractions) that can be generated by the heart Biology 141: Physiology 2 Lecture Outline Excitation-contraction coupling in cardiac muscle cells 1. AP causes voltage-gated Ca2+ channels in the cell membrane ...

  • 3 Pages

    Heart rate basics study guide

    University of Florida, APK 4125

    Excerpt: ... ases HR. Vagus nerve releases acetylcholine onto SA and AV nodes. During venous return, cardiac fibers are stretched by increased blood volume returning to the heart. Increased stretch results in greater force of contraction, which increases stroke volume. What are the five phases of cardiac muscle depolarization? Phase 0 is a rapid upswing in membrane potential. Phase 1 is a slight repolarization and Phase 2 is the plateau phase where the membrane remains in a depolarized state. The plateau lasts about 0.2 seconds. The membrane potential repolarizes during phase 3 and phase 4 in the resting phase. Explain why the myocyte is incapable of summation. The refractory period of cardiac muscle is about 250 milliseconds almost as long as the contraction of the heart. This relatively long duration of cardiac action potential and refractory period means that summation of cardiac muscle s contractions cannot occur, even when the action potential frequency is high and the heart is beating rapidly. This is good, because ...

  • 1 Pages

    Lec20_07

    Cornell, BIO 311

    Excerpt: ... Lec20- 2007 INTRODUCTORY ANIMAL PHYSIOLOGY BIOAP 311/VETBM 346 FALL 2007 OUTLINE - LECTURE 20 Cardiac Muscle - The Heart as a Pump (Readings - Chapters 13 & 15, Chp. 18 Fig. 18-3) I. 1. 2. 1. 2. 3. 4. II. 1. 2. 3. Major Topics/Concepts to be covered: Construction of the two-pump system (Fig. 15-1). Pressure gradients Anatomy of the mammalian heart. Blood flow & gradients (Figs. 15-3, 15-4). Cardiac muscle . Excitation/contraction coupling (Fig. 18-3). You will have learned the material when you can: Draw a schematic of the heart. Rationalize the structure of the heart in terms of its function. Rationalize the special characteristics of cardiac muscle and the role of specialized conducting tissue. III. Sample Problems: 1. 2. 3. 4. Why is it important for the contraction of the ventricles to start at the apex? What would be the effect of a decrease in extracellular calcium on ventricular function? What would happen if a pathology caused a reduction in the refractory period? What would be the effect of an incr ...

  • 6 Pages

    Spring07Exam4

    University of Texas, BIO 416K

    Excerpt: ... Name_ KEY - Bio416K Physiology and Functional Anatomy I Lecture Exam 4 Spring 07 1. The sarcoplasmic reticulum has the following role in skeletal muscle contraction: a. Conduction of the action potential stimulated by the end plate potential b. Contains the dihydropyridine receptor proteins that translate the sarcolemma action potential c. Regulates Na+ and K+ levels in the sarcoplasm to reduce muscle fatigue d. Supplies glycogen and fatty acids for ATP production in the sarcoplasm e. Initiates contraction by releasing calcium in response to the sarcolemma action potential 2. Manganese ions block the calcium channels in the cell membrane of contractile cardiac muscle cells. How would the presence of manganese in the extracellular fluid affect the contraction of the heart muscle? a. The plateau phase of contraction would be longer b. The action potential refractory period would be longer c. The heart would contract less forcefully d. The heart rate would increase e. The contracti ...

  • 17 Pages

    PSIO 202, Lecture 7

    Arizona, PSIO 202

    Excerpt: ... PSIO 202 Human Anatomy and Physiology Lecture 7 The Heart; Mechanics and Cardiac Output Objectives and Reading Assignment Reading: Tortora, pages 738-742 Objectives Discuss the relationship between pressure and volume in the heart chambers, as well as the position of the various heart valves, in both systole and diastole Define cardiac output and know how to calculate it, given values for heart rate and stroke volume Define and describe the major determinants of stroke volume, and the underlying mechanisms of each Define the Frank-Starling mechanism Definition of Systole and Diastole Ventricular systole starts when the AV valves close and the pressure within the ventricles begins to rise as the cardiac muscle fibers are depolarized and then contract Ventricular diastole starts with ventricular muscle repolarization, leading to a drop in ventricular pressure, and filling of the ventricle Atrial systole is very brief; thus, ventricular filling is largely passive Figur ...

  • 13 Pages

    25

    Berkeley, BIO 1A

    Excerpt: ... junction is called a neuromuscular junction; it is always excitatory, and release of neurotransmitters always surpasses threshold on the postsynaptic membrane. Notice that the line that is a plasma membrane forms a tube, and that tube goes inward, traveling inside the muscle. The blue sheet is representative of two different cisterna of sarcoplasmic reticulum. So what happens now at the neuromuscular junction is that we activate the postsynaptic membrane and it generates a graded potential that always passes threshold for the skeletal muscle cell. Therefore, the membrane of the skeletal muscle cell generates an action potential. Skeletal muscle cells can generate action potentials, cardiac muscle does, and many smooth muscles do. So, they can mount and propagate an action potential. That action potential, once generated, will propagate over the entire surface of the skeletal muscle cell. The T tubules are part of the plasma membrane, so the action potential will travel along the T tubules. So this action pote ...

  • 2 Pages

    Review quiz 8 - Lecture 14

    SUNY Stony Brook, BIO 328

    Excerpt: ... and high calcium concentration. e. At all times when myosin and actin are in contact, myosin is bound by ATP. 3. Cardiac muscle a. Different types of cardiac cells express different types of ion channels. b. Following the spread of an action potential into a T-tubule, extracellular calcium enters the cell through Ca2+-gated Ca2+ channels, and induces further calcium release from the sarcoplasmic reticulum. c. Cardiac cells communicate via gap junctions d. Cardiac muscle cells are more permeable to potassium at more negative membrane potentials. e. Tetany in cardiac muscle cells is made impossible by the prolonged refractory period, which is mostly concurrent with the period of contraction. 4. Smooth muscle a. The contraction of smooth muscle can be inhibited. b. The release of norepinephrine or epinephrine at the end plate can lead to contraction of smooth muscle. c. In some smooth muscles, dephosphorylation of myosin can occur without detachment from actin. d. Myosin light-chain phosphatase is cont ...

  • 3 Pages

    11-5-07 anatomy notes

    TCU, BIOL 20204

    Excerpt: ... 11-5-07 anatomy notes 1. Muscular System a. General Cytology of Muscle Tissues i. General Features 1. elongation and force of contraction 2. muscle cells that move during contraction become shorter in length and greater in diameter 3. conversion of chemical energy a. ATPcontractile force (mechanical energy) 4. sarcolemma (plasma membrane-at outer surface of cell) a. can pass "action potentials" or nerve impulse or depolarization wave b. stimulates muscle cell to contract 5. sarcoplasm-cytoplasm 6. myofibrils-elongated cylinders; only in cardiac and skeletal muscle a. made up of protein myofilaments i. proteins are arranged so that they contract ii. proteins are named: 1. actin 2. myosin 3. troponin 4. tropomyosin 7. mitochondria-would expect them to be in muscle because they're so active a. large size, highly numerous b. found in skeletal and cardiac muscle ii. Specific Features 1. Skeletal Muscle Cells a. elongated cylinders b. cross-striated: display banding patterns c. 1000 nuclei/cell-nuclei at p ...