Cardiovascular 1

taylormaloney's version from 2016-03-21 04:24

Section 1

Question Answer
Is Cardiac Muscle Tissue voluntarily controlled? Describe Cardiac muscle fibres.Involuntary, Striated Fibres that shorten in length.
What is Cardiac Muscle Tissue adhered to?A fibrous skeleton called 'Fibrous Pericardium', NOT bone tissue.
What are the two components of Intercalated Discs?Desmosomes and Gap Junctions
What is a Desmosome?A mechanical junction between two cardiomyocytes
What is a Gap Junction?A communicating junction that allows diffusion of ions,glucose, etc- between one cardiomyocyte to another.
What is the intercalated disc derived from?They are the thickening of Sarcolemma.
Why do Cardiac Muscle Fibres have more mitochondria than Skeletal Muscle Fibres?They require more oxygen.

Section 2

Question Answer
Does the AV Node come before the SA Node in the cardiac conduction system?No, SA node is the first in the Conduction System.
How does an action potential travel from the SA Node to the AV Node?Internodal Tracts
How does an action potential travel from SA Node to Left Atrium?Bachmann's Bundle
What is the next stop for action potentials after the AV Nodes?Atrioventricular Bundle ( Bundle of His )
The Bundle of His separates into what?Left and Right Bundle Branches.
What is the last stop for action potentials within the Cardiac Conduction System?Purkinje Fibres
Where is the only location where action potentials can conduct from the Atria to the Ventricles?The Bundle of His. ( Atrioventricular Bundle )
Why is that the only location where conduction is possible?The insulation of the fibrous skeleton of the heart prevents conduction everywhere else.
Where do Purkinje fibres conduct an action potential to?From Apex of heart, upwards into the Ventricular Myocardium.
These Action Potentials cause what to occur?Ventricular Contraction, which push blood through the Semi-lunar Valve.

Section 3

Question Answer
What are the 3 components of the Cardiac Muscle Action Potential?Depolarization, Plateau, Repolarization.
Define the Depolarization.When contractile fibres meet threshold, voltage gated Na+ channels open. Na+ levels rise causing rapid depolarization.Na+ channels inactivate.
Define the Plateau.Maintained Depolarization. Voltage Gated slow Ca+ channels open. Ca+ influx causes contraction. K+ channels open and balance influx of Ca+.
Define the Repolarization.Recovery of Resting Membrane Potential. After a delay- additional K+ channels open, and Ca+ channels close. Allows overall outflow of positive ions to restore membrane potential to -90 mV.
What is the refractory period?A time interval when a second contraction cannot occur.
What is the relevance of the refractory period?The Refractory period is longer than the contraction, this prevents continuous cardiac muscle contraction.
Do Cardiac Muscle Fibres produce ATP? Yes, via Aerobic Cellular Respiration + from Creatine Phosphate.

Section 4

Question Answer
Define Cardiac CycleA single cycle includes all events associated with one heartbeat.
Define EDVEnd Diastolic Volume- volume of blood left in ventricles at end of diastole. (130mL)
Define ESVEnd Systolic Volume- volume of blood remaining in ventricles after systole. (60mL)
Define SVStroke Volume- volume of blood ejected from ventricles with each HB. (70mL)
Define EFEjection Fraction- % of EDV that is ejected from the heart. (50-55%)
Define Q or CO.Cardiac Output- volume of blood ejected from ventricles per minute. (SV x HB)

Section 5

Question Answer
What are the 3 Factors that regulate SVPreload, Afterload, Myocardial Contractility
Define PreloadDegree of stretch on the heart before contraction. (EDV)
What factors affect EDV and therefore SV?Venous Return ( ^ in Venous Return = ^ in EDV ), & Length of Ventricular Diastole. ( ^ HR = v SV)
Define AfterloadResistance Left Ventricle must overcome to circulate blood.
What are examples of Increased / Decreased Afterload?Increased- Hypertension ( v Afterload ), Decreased- Low Blood Pressure ( ^ Afterload )
Define Myocardial ContractilityThe force of each individual muscle fibre contraction.
What are examples of Increased Contractility?Increased- ( ^ in sympathetic activity or Ca2+ level = Increased SV )
What are examples of Decreased Contractility?Decreased- ( v in sympathetic activity or ^ in K+ level = decreased SV )

Section 6

Question Answer
Can Cardiac Output be regulated?Yes, via the regulation of HR. (Stroke Volume cannot be adjusted voluntarily)
Define the mechanism of Autonomic Regulation of the heart.Central Control via CV centre in Medulla Oblongata and sensory receptors.
What are the three types of sensory receptors and what do they monitor?Proprioeceptors- movements. Chemoreceptors- blood chemistry. Baroreceptors- blood pressure.
Where are Baroreceptors located? Carotid Sinus + Arch of Aorta.
What is the effect of Sympathetic Impulses to HR / Contraction ?Increase in force of contraction and heart rate.
How do Sympathetic Impulses accomplish this?They trigger a release of Norepinephrine.
What is the effect of Parasympathetic Impulses to HR / Contraction ?Decrease in HR, does NOT effect contractility.
How do Parasympathetic Impulses accomplish this?Trigger a release of acetylcholine.
Can chemical regulation of the HR take place without Sympathetic / Parasympathetic Nerve impulses?Yes, both epinephrine and norepinephrine can also be released via the adrenal medulla.
What effect can Thyroid Hormone have on HR?It can also enhance the heart rate and contracility.
What effect would elevated levels of K+ and Na+ have on HR?Decreased HR / Contractility.
What effect would elevated levels of Ca2+ have on HR / Contractility?Increased HR / Contractility.

Section 7

Question Answer
What would the CO of a well trained athlete look like in comparison to an innactive person?CO would be much higher, HR would be lower.
The abnormality is called what? A Physiological Cardiomegaly - due to training induced cardiac hypertrophy.
What is a Pathological Cardiomegaly?A pathological hypertrophy of the heart muscle fibres. Thick fibres that are not arranged normally.
What are the three types of Arrhythmias?Bradycardia ( <50 BPM ), Tachycardia ( >100 BPM ), Fibrillation ( rapid, uncoordinated HB )
What other factors could affect HB?Age, gender, fitness, temperature.
What is the most deadly type of arrhythmia ?Ventricular Fibrillation.