The flashcards below were created by user
Anonymous
on FreezingBlue Flashcards.
-
What is the Pericardium?
it is lined by serous membrane that is subdivided into parietal and visceral
-
What is the Visceral Pericardium?
it covers closely to the heart, (like skin)
-
What is the Parietal Pericardium?
it lines the surface of the pericardial sac
-
What is the Fibrous Pericardium?
it is made of dense connective tissue, it also stabilizes the heart within the mediastinum
-
How do Gap junctions help optimize cell function? What does it mean?
Intercellular communication, it communicates through small openings between each of the cells, it helps with action potential-polarization of ions
-
Intercalcated discs do what? What do they connect?
They convey the farce of the contractions from cell to cell. The connect cardiac muscles
-
Desmosomes
help move neighboring cells as one unit (syncytium)
-
HEART FUNCTION: Prevent mixing oxygenated and deoxygenated blood
HEART ANATOMY (used): Interventricular septum, interatrial septum
-
HEART FUNCTION: Overcome resistance
HEART ANATOMY: Ventricles
-
HEART FUNCTION: Prevent backflow of blood
HEART ANATOMY: Chordae teninae, bicuspid/tricuspid valves, papillary muscles, pulonary & aortic semilunar valves
-
HEART FUNCTION: Coordination of contraction
HEART ANATOMY: Nodal cells (conducting system)
-
3 Main circulation circuits
pulmonary, coronary, systemic
-
The difference between Contractile and Conduction.
- Produce powerful contractions, has a long plateau phase, long slow twitch, long refractory period
- Controls and coordinates heartbeat
-
Cardiac Cycle
- Atria contract > push blood to ventricles > ventricles contract > push blood out of the heart
- SA node generates impulses at regular intervals with a brief pause
-
Similarities between cardiac and skeletal muscle
- Action potentials to release Ca++ to bind to troponin
- Expose active sites on the actin
- Cause sarcomere shortening and muscle contraction
-
Differences between cardiac and skeletal muscle
- Action Potentials
- Length of the contractions
-
Cardiac Contractions
- Ca++ enters from extracellular fluid during the plateau phase of action potential
- This arrival of Ca++ causes the release of Ca++ from the SR
- Skeletal muscle fiber contraction quickly, however cardiac muscles contracts longer and will continue until the plateau ends
-
Depolarization between Cardiac and skeletal muscle
- Cardiac > rapid due to fast channels and massive influx of Na+
- Skeletal > same thing
-
Resting Potential for cardiac and skeletal muscle
- Cardiac > Resting potential -90mV threshold -75mV
- Skeletal > Resting potential -85mV threshold -50mV
-
Depolarization/Plateau between cardiac and skeletal muscle
- Cardiac > voltage regulated @ +30mV > slow voltage; plateau Ca++ open, will remain open at 0mV of 175 m/sec
- Skeletal > voltage regulated +30mV; no plateau
-
Repolarization of Cardiac and Skeletal muscle
- Cardiac > slow K+ channels, open to restore resting potential
- Skeletal > same
-
Absolute Refractory period between Cardiac and Skeletal muscle
- Cardiac > During depolarization; plateau and portion of repolarization, very longSkeletal > During depolarization; normal length
-
Relative Refactory Period between Cardiac and Skeletal muscle
- Cardiac > Takes place during repolarization
- Skeletal > takes place during repolarization & hyperpolarization
-
2 types of conducting cells
- Nodal cells > Stop watch; reaches threshold first and sets heart rate
- Conducting cells > conductor; distributes stimuli to myocardium
-
Sinoatrial (SA) Node
impulse spreads across atria to atrioventricular (AV) node > AV bundle and bundle branchs via Purkinje fibers to ventricles
-
Autorhythmicity
The heart can conduct impulses without external stimulation unlike that of the skeletal muscles
-
Prepotential
Each time the heart will repolarize it and will gradually move toward threshold, (always ready to start again)
-
Difference between Bradycardia and Trachycardia
- Bradycardia is too little K+; slower than normal heart rate
- Trachycardia is too much K+; faster than normal heart rate
-
Cardiac Action Potential
- protein channels > sodium, potassium, calcium
- Started by the prepotential but it is initiated by massive influx of sodium
- The plateau is caused by calcium channels remain open for 175 m/sec at 0 mV
- Repolarization > uses potassium channels that open & calcium channels close
- (no leak channels=no hyperpolarization)
-
Sodium and potassium pump in heart
Potassium helps restore resting potential
-
Phases in the cardiac cycle
- Systole > contraction phase; ventricles together
- Diastole > Relaxation phase
-
Stroke Volume equation
SV (stroke volume)= EDV-ESV
-
3 factors that affect ESV
- Preload: filling with blood EDV
- Contractility: force produced during contraction
- Afterload: resistance in circulation ESV
-
Cardiac output equation
CO(ml/min)=heart rate(beats/min) * stroke volume(ml/beat)
-
Frank-Starling Principle
- "more in"="more out"
- Larger EDV=larger stroke volume
-
CNS Control of the Heart
- Basic control in the medulla oblongata(brain stem)
- Cardioacceleratory center > accelerate heart rate (sympathetic neurons)
- Cardioinhibitory center > lower heart rate (parasympathetic neurons)
- Blood pressure sensors (baroreceptors)
- Oxygen, carbon dioxide receptors (cemoreceptors)
-
Hormone and autonomic regulation of heart
- Parasympathetic release of Ach which extends repolarization and decrease of heart rate
- Sympathetic release of NE or E which shortens repolarization and accelerates the rate of spontaneous repolatization
-
Hormone effects on Cardiac Output
- Adrenal medulla hormones (E/NE)
- Thyroid hormones
- Glucagon
-
Blood Vessels
Arteries > Arterioles > Capillaries > Venules > Veins
-
Properties of Arteries
- Contain layers of tissue: Tunica externa(connective tissue) > Tunica media (smooth muscle) > Tunica intima (epithelium)
- Thicker walls
-
Specialized vessels
- Fenestrated Capillaries
- >contain pores or windows
- >rapid exchange of water and solutes between plasma and interstitial fluid
-
Properties of capillaries
- Exchange between blood and cells take place
- organized into interconnected capillary beds
- vasomotion of precapillary sphincters(bands of smooth muscle) controls flow
-
Properties of veins
- collect blood from capillaries
- merge into medium-sized veins
- merge then into large veins
- BP is low and valves keep blood flowing to the heart
-
Fetal Circulation
- Fetus > umbilical arteries > placenta > umbilical vein > fetus
- Umbilical vein > ductus venous
- Hepatic veins > ductus venous > inferior vena cava > right atrium > foramen ovale > left atrium > pumonary trunk > ductus arteriosus > arota > umbilical arteries
|
|