1. Cardiac Myocyte Steven C Wu, PhD [email protected] Department of Integrative Biology and Physiology Jackson 3-138 Learning Objectives: Cardiac Myocyte 1.Describe the function of intercalated discs. Specifically, discuss how gap junctions electrically connect cardiac myocytes and desmosomes physically connect cardiac myocytes. Discuss why this facilitates the myocardium working as a pump. (Think functional syncytium = many cells working as one unit) 2.Give an overview of the function of the organelles (T-tubules, SR, contractile apparatus) and proteins (voltage gated Ca2+ channels and SR calcium release channels) that are responsible for excitation-contraction coupling in cardiac muscle (i.e. calcium induced calcium release). Remember that you have encountered some of these proteins in neurons and skeletal muscle cells. Build on your previous knowledge. CT 5.1: Building a Myocyte The Cardiac Myocyte is the ___________ Cell O’Connell et al 2007 2. Give an overview of the function of the organelles (T-tubules, SR, contractile apparatus) and proteins (voltage gated Ca2+ channels and SR calcium release channels) that are responsible for excitation-contraction coupling in cardiac muscle (i.e. calcium induced calcium release). Remember that you have encountered some of these proteins in neurons and skeletal muscle cells. Build on your previous knowledge. CT 5.1: Building a Myocyte Cardiac Myocytes Connect at ________________ * Katz AM, Physiology of the Heart, 5th Ed 2011 M: mitochondria Z: Z-disc D: intercalated disc *: Transverse (T) -tubule L: lipid 1. Describe the function of intercalated discs. Specifically, discuss how gap junctions electrically connect cardiac myocytes and desmosomes physically connect cardiac myocytes. Discuss why this facilitates the myocardium working as a pump. (Think functional syncytium = many cells working as one unit). 2. Give an overview of the function of the organelles (T-tubules, SR, contractile apparatus) and proteins (voltage gated Ca2+ channels and SR calcium release channels) that are responsible for excitation-contraction coupling in cardiac muscle (i.e. calcium induced calcium release). Remember that you have encountered some of these proteins in neurons and skeletal muscle cells. Build on your previous knowledge. CT 5.1: Building a Myocyte The Cardiac ____________ is the Contractile Unit 2. Give an overview of the function of the organelles (T-tubules, SR, contractile apparatus) and proteins (voltage gated Ca2+ channels and SR calcium release channels) that are responsible for excitation-contraction coupling in cardiac muscle (i.e. calcium induced calcium release). Remember that you have encountered some of these proteins in neurons and skeletal muscle cells. Build on your previous knowledge. CT 5.1: Building a Myocyte Cardiac Muscle vs Skeletal Muscle oSmaller and have single nucleus per myocyte oBranch and join neighboring myocytes through intercalated disks • _______________ allow __________ to be transferred • _______________ provide __________ connection oT-tubules are larger and branch oSarcoplasmic reticulum is smaller oMitochondria occupy one-third of cell volume • More in number, each larger in volume 1. Describe the function of intercalated discs. Specifically, discuss how gap junctions electrically connect cardiac myocytes and desmosomes physically connect cardiac myocytes. Discuss why this facilitates the myocardium working as a pump. (Think functional syncytium = many cells working as one unit). 2. Give an overview of the function of the organelles (T-tubules, SR, contractile apparatus) and proteins (voltage gated Ca2+ channels and SR calcium release channels) that are responsible for excitation-contraction coupling in cardiac muscle (i.e. calcium induced calcium release). Remember that you have encountered some of these proteins in neurons and skeletal muscle cells. Build on your previous knowledge. CT 5.1: Building a Myocyte.