Size of heart?
like a clenched first
Heart location?
mediastinum of thorax
Heart is enclosed in a double sac made of _________ parietal outer layer and ___________ visceral inner layer.
Outer Fibrous pericardium and Inner Serous pericardium
Pericardial cavity between serous layers contains _________
serous fluid, for lubrication
Heart wall layers from inside out are __________, _________, and _______
Endocardium Myocardium, which is reinforced by fibrous skeleton Epicardium, visceral layer of the serous pericardium
Heart is single or double pump?
DOUBLE. It's only single as a fetus.
Entering the Right Atrium are the.

......

.....

.

superior vena cava, inferior vena cava, and coronary sinus
What enters the Left Atrium?
4 pulmonary veins
Right Ventricle discharges blood into the _________
pulmonary trunk
Left Ventricle pumps blood into the __________
aorta
The Right side of the Heart is the ___________ circuit pump
pulmonary circuit pump. Oxygen poor blood enters Right Atrium, then right ventricle, through the pulmonary trunk to the lungs, and back to the Left Atrium via Pulmonary Veins
Left side of Heart is the _________ circuit pump
Systemic circuit pump. Oxygen Rich blood enters Left Atrium from Lungs flows into Left Ventricle, then into Aorta, which provides supply to all body. Systemic veins return the oxygen depleted blood to the Right Atrium
Right and Left Coronary arteries branch from the _______
Aorta and via their main branches; ant and post interventricular, right marginal, and circumflex arteries
Blood delivery to myocardium occurs during ________
heart relaxation
2 kinds of Atrioventricular valves are ______ and _______
tricuspids and mitral
Tricuspid valves do what?
prevent back flow into atria when ventricles are contracting
Mitral valves do what?
prevent back flow into atria when ventricles are contracting
Pulmonary and Aortic valves or Semilunar valves do what?
prevent back flow into the ventricles when the ventricles are relaxing
Cardiac muscle structure description
branching striated mostly uni nucleus cells contain myofibrils that have sarcomeres
Adjascent cardiac cells are connected by _________
Intercalated discs containing desmosomes and gap junctions.

Myocardium behaves as a functional ___________ because of electrical coupling provided by gap junctions
synctium
Membrane depolarization of contractile __________ causes opening of sodium channels and sodium entry
myocytes
Depolarization also opens slow _____ channels
calcium
Calcium entry _______ period of depolarization, and creates a _______ on the line graph
prolongs depolarization plateau line graph
Compared to skeletal muscle, cardiac muscle has a prolonged __________ refractory period that prevents __________
tetany
Cardiac muscle has abundant __________ and depends almost entirely on _________ to make ATP
mitochondria Aerobic respiration
True or False? Certain non-contractile cardiac muscle cells exhibit automaticity and rhythmicity and can independently initiate action potentials.
True
What cells compose intrinsic conduction system of heart?
non contractile cardiac muscle cells that exhibit automaticity, which means an automatic response pattern or habit, and rhythmicity thta can independently initiate APs
Normal heart sounds arise from
turbulent blood flow during the closing of heart valves.
Abnormal heart sounds are called __________, and usually reflect problems with ________
murmurs reflect valve problems
During mid-to-late diastole..

.

Ventricles fill, Atria contract.
Ventricular systole consists of the..

.

isovolumentric contraction phase and the ventricular ejection phase
During early diastole..
the ventricles are relaxed and are closed chambers until the atrial pressure exceeds the ventricular pressure, forcing the AV valves open.
Normal heart rate is ______, and a cardiac cycle lasts ________
75 beats per minute, and cardiac cycle lasts 0.8 seconds
Pressure changes promote what?
blood flow and valve opening and closing
Cardiac output is?
the amount of blood pumped out by EACH Ventricle in 1 minute
Stroke volume is?
About 70 ml, it is the difference between end diastolic volume and end systolic volume.

Anything that influences heart rate or blood volume, hence stroke volume depending on how much cardiac muscle stretches due to venous return.

Activation of sympathetic nervous system increases ________ and ________
heart rate and contracility
Parasympathetic activation decreases _________ but has little effect on _________.
decreases heart rate, little effect on contractility.
Chemical regulation of heart is effected by _________ and _________
Hormones, like epinephrine and thyroxine, and Ions, like potassium and calcium. Ion imbalances impair heart activity
Congestive heart failure occurs when
heart can't pump enough to provide normal body circulation needs
Heart begins as a simple ________ tube
mesodermal
Heart starts pumping by what week?
4th gestational week.
Fetal heart has _____ number of lung bypasses.

2. foramen ovale and Ductus arteriosus