Week Two Flashcards
Describe the location of the heart
Located in the thoracic cavity, the heart sits behind the sternum, between the two lungs in an area called the mediastinum. It is centered in the rib cage but favours the left side.
What is the fibrous pericardium?
outer layer of connective tissue
What is the serous pericardium?
Inner membrane that folds under itself to form 2 layers: called the parietal and visceral layer
What is the parietal layer of the pericardium?
fused to the inner surface of the fibrous pericardium
What is the visceral layer (epicardium) of the pericardium
inner layer closest to the heart wall
What is the pericardial cavity and what is its function?
between the parietal & visceral layer, filled with serous fluid (pericardial fluid)
- lubricated to decrease friction as the heart beats
What are the layers of the heart wall in order?
epicardium → myocardium → endocardium
Describe the Epicardium
includes a thin layer of connective tissue containing fat deposits
Describe the myocardium
the main component that makes up the wall of the heart; mostly cardiac muscle cells (myocytes); also contains specialized pacemaker cells & connective tissue
Describe the Endocardium
Innermost layer of the heart, faces the lumen of the heart chamber; simple squamous epithelium (endothelium) and layers of connective tissue containing collagen & elastic fibers
Describe the chambers of the heart
- two atria and two ventricles
- the atria receive blood from veins and pump blood into ventricles through one-way valves
- the ventricles eject blood into arteries → carry blood through either systemic or pulmonary circuit
Where does gas exchange occur to pick up oxygen?
between air in the alveoli and blood in the pulmonary capillaries
Where does gas exchange occur to provide tissues with oxygen?
between tissues and blood in the systemic capillaries
Name the major systemic veins
superior and inferior vena cava
Name the major systemic artery
aorta
Name the major vessels of pulmonary circulation
- right and left pulmonary arteries
- right and left pulmonary veins
What separates the right and left ventricles?
interventricular septum
Describe the chambers of the heart
- the ventricles are larger than the atria and have thicker walls → much stronger pumps
- the atria are not symmetrical in size, shape of location; right atirium is larger, thinner walled, more anterior; left atrium is smaller, thicker-walled and more posterior
- the ventricles are not symmetrical
Describe the shape of the right ventricle
thin-walled and crescent shaped
Describe the shape of the left ventricle
thicker-walled and circular
What is the name of the valves between the atria and ventricles? describe them
Atrioventricular valves
tricuspid: between right atrium and right ventricle (contains 3 cusps)
bicuspid: between left atrium and left ventricle (contains 2 cusps)
What is the name of the valve between the ventricles and the pulmonary artery/aorta? Describe them
semilunar valves
pulmonary valve: between right ventricle and pulmonary trunk
aortic valve: between left ventricle and aorta
Describe pressure changes and blood flow in the heart
blood flows in response to pressure gradients. As ventricles contract and relax, pressure in chambers changes, causing blood to push on valves and open or close them
WHat happens if pressure in the ventricles is larger than pressure in the aorta/pulmonary arteries
aortic/ pulmonary valve opens