Cardiac (Test 2) Flashcards
What happens during diastole?
- The filling of a heat chamber with blood
- The heart relaxes
What happens during systole?
- Blood is ejected from a heart chamber
- The heart contracts
What are the 5 steps in the cardiac contraction cycle?
1) Late diastole
2) Atrial systole
3) Isovolumic ventricular contraction
4) Ventricular ejection
5) Isovolumic ventricular relaxion
What is late diastole?
- When both sets of chambers are relaxed and ventricles fill passively
What is atrial systole?
- When atrial contraction forces a small amount of additional blood into the ventricles
What is isovolumic ventricular contraction?
- The first phase of ventricular contraction that pushes the AV valves closed but does not open semi-lunar valves
What is ventricular ejection?
- As ventricular pressure rises and exceeds pressure in the arteries, the semi-lunar valves open and blood is ejected
What is isovolumic ventricular relaxation?
- As the ventricles relax, pressure in the ventricles falls, and blood flows back into the cups of semi-lunar valves to snap them closed
What percentage of blood can passively flow in the ventricles?
- About 70%
The bicuspid valve is also known as the?
- Mitral valve
Are arteries or veins known as volume reserves?
- Veins (about 70% of blood in body is here)
Are arteries or veins known as pressure reserves?
- Arteries
What phenomena causes the passive flow of blood from the atrium to the ventricle?
- Gravity
What are the two types of cells in the heart?
- Control cells
- Obeyer cells
Which cells control/modulate heart contractions?
- Pacemaker cells
Which cells obey pacemaker cells
- Cardiac myocytes
What kind of ions depolarize the heart?
- Calcium ions (T and L type)
How do pacemaker cells know how to fire action potentials?
- They are activated by a negative charged cytoplasm
What is the SA (sinoatrial) node?
- Initiate electrical cells in the heart
- Have HCN1 channels
What do gap junctions allow?
- Allow the quick transfer of ions
What is the AV (atrialventricular) node
- Slows the electrical signal from the SA node before being transferred to the ventricles
What is a major differentiation between skeletal muscles and cardiac muscles?
- Cardiac muscles have gap junctions
What is the P-wave?
- The culmination of the depolarization of the SA and AV nodes and the atrial muscle
What is an EKG?
- The sum of all the electrical activity in the heart
What is the QRS complex?
- A mixture the re-polarization of the SA and AV nodes and the atrial muscle, and the depolarization of the common bundle, the bundle fibers, Purkinje fibers and ventricular muscle
What is the T-wave?
- The re-polarization of the common bundle, the bundle fibers, Purkinje fibers, and ventricular muscle
- Potassium efluxes from the cell
What is and does the Vagus Nerve do?
- Innervate the SA and AV nodes
- Uses ACh to bind to M2 receptors (Gi)
- Long pre-ganglionic neuron connected to a shorter post-ganglionic neuron
What kind of tone does the heart have?
- Vagal tone
What is and does the sympathetic cardiac nerve do?
- Innervates the SA and AV nodes, and Purkinje fibers
- Uses norepinephrine (NE) to bind to β1 receptor (Gs)
- A short pre-ganglionic neuron is connected to a longer post-ganglionic neuron (pre-ganglionic neuron releases ACh and post-ganglionic neuron releases NE)
What happens when the vagus nerve is damaged?
- The sympathetic nerve take over
What is the Frank Staling Law of Heart?
- The more cardiac muscle is stretched within its limits, the more forcibly it will contract
What do beta blockers do?
- Slow down the heart
What are drugs that have lol at the end?
- Beta blockers
What component of the EKG will change when patients take Sotalol, a potassium channel blocker and why?
- Regain control of the heart by allowing a longer re-polarization phase
- Longer T wave
What is a patch clamp
- A needle pierces a skin and records electrophysiological changes
What would the effect be of increasing the extracellular concentration of Calcium in the pericardium?
- Increase in heart rate
- Depolarize the membrane quicker
- More contractile force
How would you treat patients affected by an increase in calcium in the heart?
- Agonists for the parasympathetic
- Antagonists for the sympathetic system
What would the effect be of increasing the extracellular concentration of Potassium from moderate to high levels in the pericardium?
- Potassium binds to potassium voltage gates and widens the pore to allow more to flow through or at a faster rate
Issues with the P wave are associated with what heart chambers?
- Atria
Issues with the T wave or QRS complex are associated with what heart chambers?
- Ventricles
What is atrial fibrillation?
- The lack of a P wave because of T wave mitigation
- No distinct T wave
- QRS wave will be present (big R waves)
What are the 3 layers of the blood vessels?
- Tunica interna
- Tunica media
- Tunica externa
What comprises the tunica interna?
- Endothelium
- Sub-endothelial layer
What comprises the tunica media?
- Smooth muscle (elastin)
Arteries have more tunica ___ than veins?
- Tunica media (smoother muscles)
What do cell produce a lot of?
- Carbon dioxide
What comprises the tunica externa?
- Collagen and elastic
What receptors causes vasocontriction?
- Alpha receptors (Gq)
What receptors causes vasodilation?
- Beta receptors (Gs)
cAMP is ___ in smooth muscles
- Inhibitory
What is a strong vasocontrictor?
- Angiotensin II
What is a strong vasodilator?
- Nitric Oxide
Capillaries have a thin layer of tunica ___
- Tunica intima to allow better ion exchange
How are capillaries classified?
- Continuous
- Fenestrated
- Sinusoid
What are continuous capillaries?
- Contain no breaks and exchange without loss of RBC and plasms
What are fenestrated capillaries?
- Allow the exchange of small peptides, signaling molecules
- e.g. hypothalamus
What are sinusoid capillaries?
- Allow the exchange of large proteins
- e.g. liver
What is hydrostatic pressure?
- Filtration: movement out of blood (out of capillary)
What is osmotic pressure?
- (Re)absorption: movement into blood (into capillary)
What is the lymphatic system?
- Run adjacent to arteries and veins
- Excess fluid is absorbed by lymphatic capillaries
- Returns fluid to the circulatory system
What is the purpose of the lymphatic system?
- To move insoluble molecules
- To flush toxins
- To improve nutrient distribution
What does the lymphatic system have a ton of?
- B cells
- T cells
Where does the lymphatic system connect with the circulatory system?
- The subclavian veins to superior vena cava
What happens when the lymphatic system fails?
- Fluid accumulates in tissues
- Increase in capillary pressure
- Decreased plasma proteins
- increased capillary permeability
- Blockage of lymph
What are varicose veins?
- Veins that are widened and stretched, thereby preventing the valves to from properly closing
There isn’t a lot of tunica ___ in veins
- Tunica media
Mean arterial pressure (MAP) = ?
- Cardiac output (CO) * total peripheral resistance (TPR)
