Cardiac Muscle
Skeletal Muscle Histology Skeletal Muscle Cells - _______ - are composed of a big number of _____ ______ (____) - Each ____ _____ has the _____ _____ as a ______
Skeletal Muscle Histology Skeletal Muscle Cells - fibers - are composed of a big number of muscle fibers (cells) - Each muscle fiber has the same length as a muscle
Autonomic Effects Upon the Heart (____/____) G-Proteins in the Heart - Activity of ___ ____ is controlled by two _____:
Autonomic Effects Upon the Heart (Para/Sympathetic) G-Proteins in the Heart - Activity of adenylate cyclase is controlled by two G-proteins: Gs-stimulatory and Gi-inhibitory
Autonomic Effects Upon the Heart (____/____) SNS: through ____ affects _____ PNS: through ____ affects _____
Autonomic Effects Upon the Heart (____/____) SNS: through NE affects Gs-stimulatory PNS: through Ach affects Gi-inhibitory
Autonomic NS Effects Upon Myocardium - ______ effect - ______ effect - ______ effect
Autonomic NS Effects Upon Myocardium - Inotropic effect - inc/dec force of contractions - Chronotropic effect - inc/dec frequency of HR/contractions - Vasodilatory effect - dec blood pressure, inc blood flow
Sympathetic Stimulation -> _____ 1. _____ heart rate ___ to ____/min (____) 2. _____ _____ of ______
Sympathetic Stimulation -> Norepinephrine 1. Increase heart rate up to 180-200/min (Tachycardia) 2. Increase force of contraction
Electrical Properties of the Cardiac Muscle 1. resting membrane potential in _____ _____ - ____ to ____ mV 2. resting membrane potential in _____ _____ - ____ to ____ mV 3. resting potential is _____.
Electrical Properties of the Cardiac Muscle 1. resting membrane potential in cardiac cells - -85 mV to -95 mV 2. resting membrane potential in conductive fibers - -90 mV to -100 mV 3. resting potential is stable ( - ).
Sinus Node (SA Node/Pacemaker) Anatomy: Specialized tissue close to _________ _______ remnants of _________ of __________ Characterized by _________ (______) Fibers are _______ in diameter Pacemaker elsewhere is called an __________
Sinus Node (SA Node/Pacemaker) Anatomy: Specialized tissue close to superior vena cava Phylogenic remnants of venous sinus of lower vertebrates Characterized by specialized pacemaker cells (P-cells) Fibers are 3-5 mm in diameter Pacemaker elsewhere is called an ectopic pacemaker
Skeletal Muscle Histology - ____ ____ _____ have a _____ _____ of _____ (_______), which are located just ______ the ______
Skeletal Muscle Histology - Skeletal muscle fibers have a significant number of nuclei (myonuclei), which are located just beneath the sarcolemma
Role of Calcium Ions and of the T-tubules in a Cardiac Cell 1. ____ ____ of ____ ____ is ____ developed than of ____ ____ 2. ______ of _____ _____ have _____ diameter (___ times ____ than _____ muscles) 3. ______ ______ bind _____ ions in ______ 4. ______ open _____ to the ______ of cardiac cells 5. _______ _______ significantly affects cardiac cell contraction
Role of Calcium Ions and of the T-tubules in a Cardiac Cell 1. Sarcoplasmic reticulum of cardiac cells is less developed than of skeletal muscle 2. T-tubules of cardiac cells have large diameter (5 times more than skeletal muscles) 3. Electronegative mucopolysaccharides bind calcium ions in T-tubules 4. T-tubules open directly to the outside of cardiac cells 5. Extracellular calcium significantly affects cardiac cell contraciton
1. Cardiac muscle is _______ - contain organized ____ and ____ 2. Cardiac muscle is a _______ 3. _____ _____ separate cardiac cells 4. _____ _____ in _____ _____ explain low ______ ______ 5. _____ _____ 6. _____ _____
1. Cardiac muscle is striated - contain organized actin and myosin 2. Cardiac muscle is a syncytium 3. Intercalated discs separate cardiac cells 4. Gap junctions in intercalated discs explain low electrical resistance 5. Atrial syncytium 6. Ventricular syncytium
Action Potential in a Cardiac Muscle 1. ____ _____ _____ and _____ in cardiac muscle 2. Opening of _____ _____ channels (open ____ s) - Phase ___ 3. Opening of _____ _____ channels (open ____ s) - Phase ___ 4. Maintained a ____ ____ of _____ 5. ____ ____ (____ ____) refractory period (______ to cause ______ of ______)
Action Potential in a Cardiac Muscle 1. Prolonged action potential and plateau in cardiac muscle 2. Opening of fast sodium channels (open 1/1000 s) - Phase 0 3. Opening of slow calcium channels (open 1/10 s) - Phase 2 4. Maintained a prolonged period of depolarization 5. Very long (250 ms) refractory period (impossible to cause summation of contractions)
Action Potential in a Cardiac Muscle Phase 0 - _____ - (_____ enters - ____ ____) Phase 1 - _____ - (____ channels start to ______) Phase 2 - _____ - (____ enters about ____ ____) Phase 3 - _____ - (____ channels ____) Phase 4 - _____ restored (____ _____)
Action Potential in a Cardiac Muscle Phase 0 - Depolarization (Na+ enters - 2 msec) Phase 1 - Early repolarization (Na+ channels start to inactivate) Phase 2 - Plateau (Ca2+ enters about 200 msec) Phase 3 - Repolarization (K+ channels open) Phase 4 - Ion distribution restored (Na+/K+ pump)
Action Potential in a Cardiac Muscle Phase 0 - ____ - ___ enters about _____ Phase 1 - ____ - ___ channels start to _____ Phase 2 - ____ - ___ enters about _____ Phase 3 - ____ - ___ channels ____ Phase 4 - _______ - _____ _____
Action Potential in a Cardiac Muscle Phase 0 - Depolarization - Na+ enters in about 2 msec Phase 1 - Early Repolarization - Na+ channels start to inactivate Phase 2 - Plateau - Ca2+ enters about 200 msec Phase 3 - Repolarization - K+ channels open Phase 4 - Ion Distribution Restored - Na+/K+ pump "DEPRI"
Cardiac Cell Histology - connected through _____ _____ - cardiac muscle is a ______ - _____ _____ in _____ _____ are similar to those in _____ _____ - _____ _____ in _____ _____ provide ____ ____ ____
Cardiac Cell Histology - connected through intercalated discs - cardiac muscle is a synctium - gap junctions in intercalated discs are similar to those in smooth muscles - gap junctions in intercalated discs provide low electrical resistance
Cardiac Cell Histology Cardiac cells - ________ - are arranged in _______ and are ________ than _______ _______ - Cardiac muscle has properties of a ______ _______ and of a _______ _______ - Cardiac muscle cell has _____ nuclei (_______)
Cardiac Cell Histology Cardiac cells - myocytes - are arranged in layers and are shorter than skeletal muscles - Cardiac muscle has properties of a skeletal muscle and of a smooth muscle - Cardiac muscle cell has 1-2 nuclei (myonuclei)
Cardiac Output Heart Rate (____/min) - Determined by _____ effects upon the ____ ____
Cardiac Output Heart Rate (68-72/min) - Determined by autonomic effects upon the SA node (pacemaker)
Cardiac Output Stroke Volume (____ ml) 1. ______ Control (_____ _____) 2. ______ Control (_____ _____)
Cardiac Output Stroke Volume (65-75 ml) 1. Intrinsic control (Venous return) 2. Extrinsic control (Sympathetic stimulation)
Cardiac Output = ______ X ________
Cardiac Output = Heart Rate X Stroke Volume
Cardiac Reserve - _______
Cardiac Reserve - difference between the cardiac output at rest and the maximum output
General Organization of Circulatory System
Closed System Heart Arterial System Venous System Microcirculation Systemic Circulation Pulmonary Circulation "CHAVSMP"
Excitation-Contraction Coupling 1. ____ _____ 2. ____ _____ - resting ____ ____ is _____ - __% of ____ enters via _____ _____ through _____ into _____ ______ - _____ is released from the _____ _____ 3. _____ combines with ______ 4. _____ _____ is removed 5. _____ are formed 6. Contraction
Excitation-Contraction Coupling 1. Action potential 2. Calcium transients - resting cytosolic calcium is increased - 10% of calcium enters via calcium influx through T-tubules into sarcoplasmic reticulum - calcium is released from the sarcoplasmic reticulum 3. Calcium combines with troponin 4. Tropomyosin's inhibition is removed 5. Cross-bridges are formed 6. Contraction
Frank-Starling Law of Heart
Frank-Starling Law of Heart - heart normally pumps all the blood delivered to it - cardiac output is regulated by venous return - cardiac output is controlled mainly by peripheral factors - provides beat-to-beat self-regulation - heart has a pumping limit (plateau level) stroke volume of the heart increases in response to an increase in the volume of blood filling the heart, cardiac muscle contracts more forcefully
Heart Sounds During Cardiac Cycle - Second heart sound (S2) - "____" - (____ vibration at ____ of systole) - ______ seconds - components: 1.____ 2. ____ - ____ frequency than S1
Heart Sounds During Cardiac Cycle - Second heart sound (S2) - "dup" - (Aortic vibration at end of systole) - 0.11 seconds - components: 1. aortic 2. pulmonic - higher frequency than S1
Heart Sounds During Cardiac Cycle - Third heart sound (S3) - ____ ____ sound, recorded in the ______
Heart Sounds During Cardiac Cycle - Third heart sound (S3) - occasional weak sound, recorded in the phonocardiogram
Heart Sounds During Cardiac Cycle - When ____ ____, ____ ____ develops - The ____ ____, _____, and _____ _____ vibrate - Sound travels through the chest - Frequency __ Hz -> __ Hz -> __ Hz
Heart Sounds During Cardiac Cycle - When valves close, pressure gradient develops - The surrounding tissue, fluids, and blood vessels vibrate - Sound travels through the chest - Frequency 3 Hz - 40 Hz - 500 Hz
Heart Sounds During Cardiac Cycle Abnormal: ________
Heart Sounds During Cardiac Cycle Abnormal: murmurs
Heart Sounds During Cardiac Cycle Normal - First heart sound (S1) - "____" - ( _____ vibration at ____ of systole) - ______ seconds - components: 1. ____ 2. ____
Heart Sounds During Cardiac Cycle Normal - First heart sound (S1) - "lub" - (AV valves vibration at beginning of systole) - 0.14 seconds - components: 1. mitral 2. tricuspid
Heart Sounds During Cardiac Cycle Normal - First heart sound (S1) - "____" - Second heart sound (S2) - "____" - Third heart sound (S3) - _____ _____ sound
Heart Sounds During Cardiac Cycle Normal - First heart sound (S1) - "lub" - Second heart sound (S2) - "dup" - Third heart sound (S3) - occasional weak sound, recorded in the phonocardiogram
Parasympathetic Stimulation -> ____ 1. _____ heart rate (____) 2. _____ _____ stimulation can _____ heart rate 3. Parasympathetic activity has _____ effect on force of contraction
Parasympathetic Stimulation -> Acetylcholine 1. Decrease heart rate (Bradycardia) 2. Strong vagal stimulation can stop/block heart rate 3. Parasympathetic activity has no effect on force of contraction * Only very strong vagal stimulation may decrease force of contraction by 20-30%
Heart Wall Morphology
Pericardium Epicardium Myocardium Endocardium "Pepi Mendo"
Phenomenon of Natural Excitation of the Heart and Conductive System - Cycle is initiated by ____ ____ of ___ ___ in the ____ ____
Phenomenon of Natural Excitation of the Heart and Conductive System - Cycle is initiated by spontaneous generation of action potential in the sinus node
Physiological Anatomy of the Myocyte - _____ is surrounded by the plasma membrane - ______. - _____ of the cardiac cell contains _____ _____ (_____). - _____ also contains _____ _____. - _____ - _____ and _____ have a _____ orientation along the axis of a ____ ____/_____. - Thin filament (____) is anchored to the ____ (____). - Distance between two _____ is a functional unit of the cardiac cell - ______ - Between ______, _______ are abundant - The ____ ____ ____ (____ ____) is a ____ ____ of ____ ____ in the cell
Physiological Anatomy of the Myocyte - Myocyte is surrounded by the plasma membrane - sarcolemma. - Cytoplasm of the cardiac cell contains contractile proteins (myofilaments). - Cytoplasm also contains carbohydrate glycogen. - Myofilaments - actin and myosin have a parallel orientation along the axis of a muscle fiber/myocyte. - Thin filament (actin) is anchored to the Z-disc (Z-line). - Distance between two Z-lines is a functional unit of the cardiac cell - sarcomere - Between myofibrils, mitochondria are abundant - The smooth endoplasmic reticulum (sarcoplasmic reticulum) is a storing site of calcium ions in the cell
Volumes and Pressures During Cardiac Cycle - ESP - EDP - ESV - EDV - Stroke Volume
Volumes and Pressures During Cardiac Cycle - ESP - 120 mmHg - EDP - 4 mmHg - ESV - EDV - Stroke Volume - 65-75 mL left ventricle