The cardiovascular System 1 Flashcards
The location of the heart
- inside the pericardial cavity
- posterior to the sternum
- medial to the lungs
- anterior to the thoracic cerebral column
- superior to the diaphragm
- inferior to the great vessels
The heart is covered by a
A double layered membrane called the pericardium
How many layers of pericardial membranes are around the heart?
3
The 3 types of pericardium
Fibrous: The outermost layer made of fibrous(dense irregular) connective tissue
Partial: the serous membrane that lines the fibrous pericardium
Visceral/epicardium: the serous membrane that is on the surface of the heart muscle
The heart wall
Has 3 layers:
Epicardium: outermost layer
Myocardium: thick muscular layer in the middle of these 3
- has the cardiac skeleton
Endocardium: innermost layer:
- covers the inner surface of the heart and valves
- continuous with the endothelium of blood vessels
What are the function(s) of the cardiac skeleton?
A. Provides structural support around the valves and the openings of the great vessels.
B. Anchors heart muscles and gives them something to pull against.
C. Serves as an electrical insulation between the atria and the ventricles.
D. All of the above.
D
The 4 chambers of the heart
Right and left atria: collecting chambers
- located in the superior regions of the heart
Right and left ventricles: pumping chambers
- located in the inferior regions of the heart
Atria
The right and left atrias are separated by the interatrial septum
- in the fetal heart, an interartial opening called the foramen ovale allows blood to bypass the pulmonary circulation
Fossa ovalis: a depression that stays as a remnant in adults
Auricle
A pouch like structure on the anterior surface of the heart on each atrium
- an ear-shaped projection that increases atrial volume.
- also known as atrial appendages.
The left and right ventricles
Are separated by a thick muscular structure called the inter ventricular septum
The ventricles
The right ventricle:
- has a thinner myocardium
- contracts against the left ventricular wall
The left ventricle:
- has a much thicker myocardium and round cross sectional area
Ventricles:
More info
The left ventricle ejects the same volume of blood, generates more pressure and pumps against more resistance compared to the right ventricle
Heart valves
Act as gates to regulate blood flow
The 2 types:
Atruoventiculatar (AV) valves seperate atria and ventricles
- tricuspid valve on the right
- bicupsid valve on the left
Two semilunar(SL) valves seperate the ventricles and vessels
- pulmonary valve on the anterior
- aortic valve on the posterior
AV Valves
Anchored by tendon-like cords called tendon chordea(aka heart strings) attached to papillary muscle which contract to brace the valves during ventricular contraction
SL valves
Don’t need muscular braces because the 3 symmetrical cusps support each other forming a y shape
Heart valve functions
- allow the forward flow of blood when valves are open
- prevent the back flow of blood when the valves are closed
What happens when the valves don’t close properly
backflow or regurgitation can happen.
What happens when the valves don’t open properly
Stiff and inflexible valves prevent them from fully opening, and not enough blood flows through. Blood backups also increase pressure in the circuit
The heart is essentially
two pumps side by side: one right and one left.
The right side called the pulmonary circuit pumps blood to the lungs;
The left side called the systemic circuit pumps blood to all other tissues and organs.
