Module 6: Comparative Anatomy Of The Cardiovascular System Flashcards
The heart
A muscular organ that pumps blood throughout the body → keeps the animal alive
Mammalian heart
Made of 4 chambers: 2 atria and 2 ventricles
One atrium and one ventricle on each side of the heart: right and left sides → separated by a septum
AV valves → separate the atria and ventricles
Atrio-ventricular (AV) valves
Separate the atria and ventricles from each other
Interventricular septum
The septum that separates the ventricles
Thicker than the septum that separates the atria
Why is the heart a unique organ?
- Made of cardiac muscle, which is specialized muscular tissue
- Has intrinsic contracting ability without having a stimulus
- Heart rate increased or decreased via autonomic nerves and other mediators
- Nutrient supply to the heart is via a small fraction of the blood that it pumps → distributed via the coronary blood vessels
Syncytium
The network that the cardiac muscles arranged to form
Makes all the fibers contract together at the same time → how the atria and ventricles can contract in a coordinated way to pump blood
The heart’s intrinsic contracting ability without a stimulus
- Impulse for contraction originates from the Sino-atrial node →
- It’s transmitted to the AV node →
- It’s propagated to the rest of the heart via specialized fibers that form the “Bundle of His” (purkinje fibers)
Papillary muscles
Specialized muscles that make up the inside walls of the heart → especially in the ventricles that are attached to the AV valves
Chordae tendinae
Thick chords that attach the papillary muscles to the valves
Endocardium
A thin membrane that covers the inside of the heart
Myocardium
The heart muscle itself
Epicardium
A thin membrane that covers the outside of the heart
Difference in thickness between the right and left ventricular walls and Why
The difference: the right ventricular wall is very thin compared to the left ventricular wall
Why: the left ventricle works the hardest to push blood at high pressure to the rest of the body
Coronary groove
The groove that runs around the heart separating the atria from the ventricles
It contains the coronary blood vessels
Left vs. Right ventricles
Left ventricle = very large vs. the right ventricle
The left ventricle has to be strong enough to pump blood through the aorta to the rest of the body → causes the left ventricle to extend to both the right and left side of the heart
2 grooves on either side of the heart that separate the right from the left ventricle → the paraconal and subsinosal grooves
Paraconal groove
Located beside the conus arteriosus that’s on the right ventricle
Conus arteriosus
A come- shaped prominence on the right ventricle from which the pulmonary trunk arises
Subsinosal groove
Located below the coronary sinus (in the right atrium)
Coronary sinus
A “pool” that collects venous blood from the heart muscle
Pericardial sac
A fibrous sac that covers the heart → contains a few millimeters of a thin, watery fluid called “pericardial fluid”
It’s a protective covering for the heart
Blood vessels
Form a critical part of the circulatory system → transport blood throughout the body
Major types → arteries, veins, arterioles, venules, capillaries
Arteries
Carry blood from the heart to various organs and tissues
Made of 3 layers: tunica intimate, tunica media, tunica adventitia
Tunica intima
Thinnest layer of an artery
Made of endothelial cells surrounded by connective tissue
Tunica media
Thickest layer of an artery
Made of elastic fibers, connective tissue vascular smooth muscles
Tunica adventitia
Outermost layer of an artery
Made of connective tissue
Contains nerves that regulate the vessels
Characteristics
