WGU D313: Anatomy and Physiology II – Verified PA &
OA Study Guide Exam Prep 2025 | Western Governors
University
Myocardium
muscular, middle layer of the heart.
Contains cardiac muscle fibers
Where is the base of the heart located?
At the third costal cartilage
Where is the apex of the heart located?
5th intercostal space, midclavicular line
Layers of the heart from outer to inner
(Heart only)
Epicardium
Myocardium
Endocardium
Layers of the heart from outer to inner (six layers)
Fiberous pericardium
Parietal layer of serious pericardium
Pericardial cavity
Epicardium
Myocardium
Endocardium
function of pericardium
protects the heart and retains its position in the mediastinum
Serosal pericardium
Closed sac composed of two thin layers (visceral and parietal) with a narrow cavity (pericardial
cavity) between them filled with pericardial fluid.
Function of the serosal pericardium
Reduces friction as the heart beats
,What layer of the heart covers the heart valves?
endocardium
Pericardium
A thin, fluid filled sac that covers the outer surface of the heart
pericardial cavity
A narrow cavity filled with pericardial fluid
Pericardial fluid
Thin serous fluid found in the pericardial cavity
Pathway of blood through the heart
Right atrium,
tricuspid valve,
right ventricle,
pulmonary semilunar valve,
pulmonary trunk,
pulmonary arteries,
lungs,
pulmonary veins,
left atrium,
bicuspid (mitral) valve,
left ventricle,
aortic semilunar valve
Venules
small vessels that gather blood from the capillaries into the veins
Blood goes from the inferior and superior vena cava to...
Right atrium
Valve after right atrium
Tricuspid valve
Right AV valve
Tricuspid valve leads to
right ventricle
What valve does the right ventricle send blood through?
,Pulmonary valve
Pulmonary vein leads to the
left atrium
Blood goes from the left atrium through what valve?
Mitral valve
Left AV valve
Mitral valve leads to what chamber
Left ventricle
Blood exits, the left ventricle through what valve?
Aortic valve
Three main types of arteries
1. Elastic arteries (conducting arteries)
2. Muscular arteries (distributing arteries)
3. Arterioles (resistance vessels)
layers of arteries and veins
tunica interna,
tunica media,
tunica externa
layers of arterioles and venules
Tunica interns,
Tunica media
Tunica externa
Function of elastic arteries
stretch when blood is forced out of the heart, and recoil under low pressure
layers of capillaries
only tunica intima
Muscular arteries (distributing arteries)
lack elastic fibers in the walls.
Smooth muscles maintain, sustained pressure.
, Well-defined walls
Repeatedly branch until they reach their target organ
Arterioles (resistance vessels)
Thin, porous, microscopic arteries that feed blood to the capillaries
Terminal end of atrerioles
Metarteriole
What regulates blood flow in arterioles
Sympathetic nerves
Localized, chemical mediators
vascular resistance
Resistance to the flow of blood through the vessels
Microcirculation
Circulation of blood in the capillaries
Properties of capillaries
Single layer of endothelial cells
Form networks to provide a large surface area in contact with tissues
Where exchange happens between vessels and tissue
What is vasomotion?
Intermittent contraction, relaxation of the pre-capillary sphincter that pushes blood from a
metarteriole to a capillary.
Names of the capillary exchange mechanisms, the facilitate movement of substances, to
inform the exchange site
Diffusion
Bulk flow (reabsorption, and filtration)
Transcytosis (vascular transport)
Active transport
Diffusion
OA Study Guide Exam Prep 2025 | Western Governors
University
Myocardium
muscular, middle layer of the heart.
Contains cardiac muscle fibers
Where is the base of the heart located?
At the third costal cartilage
Where is the apex of the heart located?
5th intercostal space, midclavicular line
Layers of the heart from outer to inner
(Heart only)
Epicardium
Myocardium
Endocardium
Layers of the heart from outer to inner (six layers)
Fiberous pericardium
Parietal layer of serious pericardium
Pericardial cavity
Epicardium
Myocardium
Endocardium
function of pericardium
protects the heart and retains its position in the mediastinum
Serosal pericardium
Closed sac composed of two thin layers (visceral and parietal) with a narrow cavity (pericardial
cavity) between them filled with pericardial fluid.
Function of the serosal pericardium
Reduces friction as the heart beats
,What layer of the heart covers the heart valves?
endocardium
Pericardium
A thin, fluid filled sac that covers the outer surface of the heart
pericardial cavity
A narrow cavity filled with pericardial fluid
Pericardial fluid
Thin serous fluid found in the pericardial cavity
Pathway of blood through the heart
Right atrium,
tricuspid valve,
right ventricle,
pulmonary semilunar valve,
pulmonary trunk,
pulmonary arteries,
lungs,
pulmonary veins,
left atrium,
bicuspid (mitral) valve,
left ventricle,
aortic semilunar valve
Venules
small vessels that gather blood from the capillaries into the veins
Blood goes from the inferior and superior vena cava to...
Right atrium
Valve after right atrium
Tricuspid valve
Right AV valve
Tricuspid valve leads to
right ventricle
What valve does the right ventricle send blood through?
,Pulmonary valve
Pulmonary vein leads to the
left atrium
Blood goes from the left atrium through what valve?
Mitral valve
Left AV valve
Mitral valve leads to what chamber
Left ventricle
Blood exits, the left ventricle through what valve?
Aortic valve
Three main types of arteries
1. Elastic arteries (conducting arteries)
2. Muscular arteries (distributing arteries)
3. Arterioles (resistance vessels)
layers of arteries and veins
tunica interna,
tunica media,
tunica externa
layers of arterioles and venules
Tunica interns,
Tunica media
Tunica externa
Function of elastic arteries
stretch when blood is forced out of the heart, and recoil under low pressure
layers of capillaries
only tunica intima
Muscular arteries (distributing arteries)
lack elastic fibers in the walls.
Smooth muscles maintain, sustained pressure.
, Well-defined walls
Repeatedly branch until they reach their target organ
Arterioles (resistance vessels)
Thin, porous, microscopic arteries that feed blood to the capillaries
Terminal end of atrerioles
Metarteriole
What regulates blood flow in arterioles
Sympathetic nerves
Localized, chemical mediators
vascular resistance
Resistance to the flow of blood through the vessels
Microcirculation
Circulation of blood in the capillaries
Properties of capillaries
Single layer of endothelial cells
Form networks to provide a large surface area in contact with tissues
Where exchange happens between vessels and tissue
What is vasomotion?
Intermittent contraction, relaxation of the pre-capillary sphincter that pushes blood from a
metarteriole to a capillary.
Names of the capillary exchange mechanisms, the facilitate movement of substances, to
inform the exchange site
Diffusion
Bulk flow (reabsorption, and filtration)
Transcytosis (vascular transport)
Active transport
Diffusion
