Midterm 2 (Part 2) Flashcards
Excitation Contraction Coupling (Skeletal Muscle)
Somatic motor neuron releases ____ at NMJ. Net entry of ____ through ACh receptor channel initiates muscle AP. AP alters conformation of ______________ which opens ________. Calcium enters the cytoplasm.
ACh
Na+
Dihydropyridine L-type Ca2+ channel
Ryanodine receptor channel
RyR is _______________ gated.
Mechanically
___________ are force producing myocardial cells and pump ______.
Myocytes
Blood
Pacemakers generate _____________, rhythmic AP’s which are responsible for ______________.
Spontaneous
Heartbeat
Cardiac myocytes are connected in series by intercalated disks which contain ___________ and ________________ (electrical coupling).
Desmosomes
Gap junctions
Smooth muscles have no ______________ and T-tubules.
Sarcomeres
Excitation Contraction Coupling (Cardiac Myocytes)
AP enters cell from adjacent cell causing ____ influx. Voltage-gated Ca2+ channel ______ and calcium enters the cell. Ca2+ binds to ___________ and triggers the channel to open. The local release causes a ___________ creating a calcium signal. Calcium ions bind to ___________ for contraction.
Na+ Opens SR RyR Ca2+ spark Troponin
The cardiovascular system consists of …
Blood
Heart
Blood vessels
The major blood vessels are …
1 Inferior and Superior Vena Cava
2 Pulmonary arteries
3 Pulmonary veins
4 Aorta
The heart is surrounded by ___________ to reduce fiction on the heart.
Pericardium
_______________ prevent AV valves from inverting.
Chordae tendinae
The atrioventricular valves consists of …
Tricuspid
Bicuspid (Mitral)
The semilunar valves consists of …
Pulmonary
Aortic
Ventricular CONTRACTION cause AV valves to _________, and semilunar valves to _________.
Close
Open
Ventricular RELAXATION cause AV valves to _________, and semilunar valves to _________.
Open
Close
What are the phases of Ventricular AP (Cardiomyocytes)?
0 - Rapid Upstroke (Depolarization) 1 - Notch 2 - Plateau 3 - Rapid Repolarization 4 - Rest
End-Diastolic Volume is _________.
135 mL
End-Systolic Volume is ________.
~65mL
Heart sounds are vibrations associated with valve closure.
LUB - DUB
S1 - S2
AV - Semilunar
Stroke volume is the AMOUNT of blood pumped by one _________ during a contraction.
SV = EDV - ESV
~70mL/beat
Ventricle
Cardiac output is the VOLUME of blood pumped by one ventricle in a given time. What is the equation?
CO = HR * SV
~5L/min
What are the mechanical events of 1 Cardiac Cycle?
Late Diastole (ventricles fill passively)
Atrial Systole (forces extra blood into ventricles; PASSIVE)
Isovolumic Ventricular Contraction (no blood ejection)
Ventricular Ejection (semilunar valve OPENS)
Isovolumic Ventricular Relaxation (blood flows back into cusps of semilunar valves and snaps them close)
The Wiggers Diagram
What are the events that take place starting with the left chambers?
1 Mitral valve CLOSES. 2 Aortic valve OPENS. 3 EDV 4 Aortic valve CLOSES. 5 Mitral valve OPENS. 6 ESV
Autonomic effect on …
SA Node are Parasympathetic _____ on M2 receptor or Sympathetic ___ on Adrenergic B1 receptor.
Ventricular Myocytes have an ___________ effect.
ACh
NE
Ionotropic
______________ is a regulatory protein that alters SERCA activity.
Phospholamban
Pacemaker AP’s are driven by __________________________________ which conduct Na+ and K+.
Hyperpolarization-activated Cyclic nucleotide gated channels (HCN)
Action potentials are initiated in the _________ to set the pace of the heart (~70 bpm).
SA Node
The structures of electrical conduction in the heart are …
AV node
SA node
Purkinje fibers
Tachycardia is where the HR is _________ than normal.
Faster
Ventricular fibrillation is where the heart does not function as an effective _____ which can lead to death.
Pump
P wave =
Atrial depolarization
QRS complex =
Atrial repolarization
Ventricular depolarization*
T wave =
Ventricular repolarization
Arteries are _________ reservoirs and are highly elastic.
Pressure
Arterioles are the point of regulation and have lots of _______ muscles. Arterioles have __________ resistance.
Smooth
Variable
Veins are _______ reservoirs, where they easily receive more blood at rest.
Volume
Blood Flow =
Cardiac Output (CO)
Metarterioles can act as _______________ if sphincters are closed. The also allow _______ molecules to reach venous circulation.
Bypass channels
Large
Mean Arterial Pressure (MAP) =
Proportional to CO * Resistance
Diastolic pressure + 1/3 Pulse pressure
Ranges from 70-110 mmHg
What are factors that increase MAP?
1 ⬆️ Blood volume (fluid intake)
2 ⬆️ CO
3 ⬆️ Resistance (decrease radius of arterioles)
4 ⬆️ Venous constriction (decrease radius of veins)
Myogenic Autoregulation is ___________ control. The __ in pressure leads to vasoconstriction which __ blood flow.
Opens mechanically-gated channels (smooth muscle) ➡️ Depolarization ➡️ Opens voltage-gated Ca2+ channels
Reflexive
⬆️
⬇️
Arteriole diameter is controlled by the tonic release of ______________.
Norepinephrine
⬆️NE = Constriction
⬇️Ne = Dilation
SNS Effects
Smooth muscle (General)
α1
Gq
Vasoconstriction
SNS Effects
Smooth muscle (Liver/Heart)
β2
Gs
Vasodilation
SNS Effects
Cardiac Muscle
β1
Gs
⬆ ️Stroke Volume
