Chapter 20 Flashcards
All large organisms must transport materials through the body involving 3 steps:
- Dissolve essentials in water (i.e., plants = sap, animals = blood)
- Have vascular elements (tubes) leading to all regions.
- Power required to move the fluid throughout the body.
Heart is located in the
mediastinum (area from sternum to the vertebral column between lungs)
Apex -
directed anteriorly, inferiorly and to the left
Base -
directed posteriorly, superiorly and to the right
Anterior surface -
deep to the sternum and ribs
Inferior surface -
rests on the diaphragm
Right border -
faces right lung
Left border (pulmonary border) -
faces left lung
Heart has 2 surfaces:
anterior (superior) and inferior
heart has 2 borders:
right and left
Fibrous pericardium
dense irregular CT
protects and anchors the heart, prevents overstretching
Serous pericardium
thin delicate membrane contains : parietal layer-outer layer pericardial cavity with pericardial fluid visceral layer (epicardium)
epicardium
visceral layer of serous pericardium
myocardium
cardiac muscle layer is the bulk of the heart
Endocardium
chamber lining & valves
Cardiac muscle fibers swirl
diagonally around the heart in interlacing bundles
Sulci -
grooves on surface of heart containing coronary blood vessels and fat
- coronary sulcus
- anterior interventricular sulcus
- posterior interventricular sulcus
Right atrium receives blood from 3 sources:
superior vena cava, inferior vena cava and coronary sinus
Right atrium also:
Interatrial septum partitions the atria
Fossa ovalis is a remnant of the fetal foramen ovale
Tricuspid valve
Tricuspid valve does:
Blood flows through into right ventricle
has three cusps composed of dense CT covered by endocardium
Right Ventricle
Papillary muscles (raised bundles of cardiac muscle)
Chordae tendineae
Interventricular septum
Pulmonary semilunar valve
Chordae tendineae
cords between valve cusps and papillary muscles
Interventricular septum
partitions, ventricles, septum
Pulmonary semilunar valve
blood flows into pulmonary trunk
Left Atrium:
Forms most of the base of the heart
Receives blood from lungs - 4 pulmonary veins (2 right + 2 left)
Bicuspid valve
Bicuspid valve:
: blood passes through into left ventricle
Has two cusps
LAMB
Left Atrioventricular, Mitral, or Bicuspid valve
Left Ventricle:
Forms the apex of heart
Chordae tendineae anchor bicuspid valve to papillary muscles
Aortic semilunar valve
Aortic semilunar valve:
blood passes through valve into the ascending aorta
just above valve are the openings to the coronary arteries
Myocardial Thickness and Function
Thickness of myocardium varies according to the function of the chamber
Atria are thin walled, deliver blood to adjacent ventricles
Ventricle walls are much thicker and stronger, why?
right ventricle supplies blood to the lungs (little flow resistance)
left ventricle wall is the thickest to supply systemic circulation
Myocardium of left ventricle is
much thicker than the right.
Fibrous Skeleton of Heart includes:
Dense CT rings surround the valves of the heart, fuse and merge with the interventricular septum
Support structure for heart valves
Insertion point for cardiac muscle bundles
Electrical insulator between atria and ventricles
prevents direct propagation of AP’s to ventricles
