Act 13 A - The Heart Flashcards
The heart is located in the _____, the cavity between the lungs.
mediastinum
True or False
The heart is tilted so that its pointed end, the apex, points downward toward the RIGHT hip, while the broad end, the base, faces upward toward the LEFT shoulder.
False
The heart is tilted so that its pointed end, the apex, points downward toward the LEFT hip, while the broad end, the base, faces upward toward the RIGHT shoulder.
The pointed end of the heart is the _____
apex
The broad end of the heart is the _____
base
What are the three layers of the heart?
Epicardium, Myocardium, and Endocardium
The visceral layer of the serous pericardium
epicardium
The muscular part of the heart that consists of contracting cardiac muscle and non contracting Purkinje fibers that conduct nerve impulses
myocardium
Cardiac cells (cardiomyocytes) are in this layer
myocardium
The thin, smooth, endothelial, inner lining of the heart, which is continuous with the inner lining of the blood vessels
endocardium
What are the four heart chambers?
Left/Right atrium and ventricle
It receives deoxygenated blood from right atrium via right atrioventricular orifice and sends it to lungs via pulmonary trunk.
Right Ventricle
It receives deoxygenated blood from the body via superior vena cava, inferior vena cava and coronary sinus.
Right Atrium
It receives oxygenated blood from the lungs via pulmonary veins
Left Atrium
It receives oxygenated blood from left atrium via left atrioventricular orifice and sends it to body via aorta
Left Ventricle
The atrioventricular valve that prevents backflow of blood from RV to RA
Tricuspid
The atrioventricular valve that prevents backflow of blood from LV to LA
Mitral
The semilunar valve that prevents backflow of blood from Aorta to LV
Aortic
The semilunar valve that prevents backflow of blood from Pulmonary trunk to RV
Pulmonic
The central opening of a blood vessel
Lumen
The lumen is surrounded by a wall consisting of three layers:
Tunica intima (Interna), Tunica media, Tunica adventitia (Externa)
_____ is the inner layer facing the blood.
tunica intima
_____ is composed of an innermost layer of endothelium (simple squamous epithelium) surrounded by variable amounts of connective tissues.
tunica intima
_____ is the middle layer
tunica media
______ is composed of smooth muscle with variable amounts of elastic fibers
tunica media
______ is the outer layer
tunica adventitia
_____ is composed of connective tissue
tunica adventitia
Tunica intima is composed of _____
an innermost layer of endothelium (simple squamous epithelium) surrounded by variable amounts of connective tissues
Tunica media is composed of _____
smooth muscle with variable amounts of elastic fibers
Tunica adventitia is composed of _____
connective tissue
The cardiovascular system consists of three kinds of blood vessels that form a closed system of passageways:
Arteries, Capillaries, and Veins
_____ carry blood away from the heart.
Arteries
The three kinds of arteries are:
elastic, muscular, arterioles
Elastic arteries are _____ arteries
conducting arteries
_____ are the largest arteries and include the aorta and other nearby branches
Elastic arteries
The _____ of elastic arteries contains a large amount of elastic connective tissue, which enables the artery to expand as blood enters the lumen from the contracting heart.
tunica media
Muscular arteries are _____
conducting arteries
_____ branch from elastic arteries and distribute blood to the various body regions
Muscular arteries
_____ are small, nearly microscopic blood vessels that branch from muscular arteries
Arterioles
_____ regulate the flow of blood into capillaries by vasoconstriction and vasodilation.
Arterioles
Arterioles regulate the flow of blood into capillaries by _____ and _____
vasoconstriction and vasodilation
_____ are microscopic blood vessels with extremely thin walls.
Capillaries
Only the ______ is present in the walls capillaries, and some walls consist exclusively of a single layer of _____
tunica intima, endothelium
_____ penetrate most body tissues with dense interweaving networks called capillary beds
Capillaries
_____ are the blood vessels between arterioles and venules.
Metarterioles
Metarterioles are also called
precapillaries
The tail end of the metarteriole that connects to the venule and lacks smooth muscle.
thoroughfare channel
_____ form the bulk of the capillary bed. They branch away from a metarteriole at its arteriole end and return to merge with the metarteriole at its venule end (thoroughfare channel).
True capillaries
The _____ regulates blood flow through the capillary.
precapillary sphincter
The three types of true capillaries are:
continuous, fenestrated, and sinusoidal
_____ have continuous, unbroken walls consisting of cells that are connected by tight junctions.
Continuous capillaries
_____ have continuous walls between endothelial cells, but the cells have numerous pores (fenestrations) that increase their permeability.
Fenestrated capillaries
These capillaries are found in the kidneys, lining the small intestine, and in other areas where a high transfer rate of substances into or out of the capillary is required.
Fenestrated capillaries
_____ have large gaps between endothelial cells that permit the passage of blood cells.
Sinusoidal capillaries
These capillaries are found in the bone marrow, spleen, and liver.
Sinusoidal capillaries
_____ carry blood toward the heart.
Veins
The three kinds of veins are:
Postcapillary venules, Venules, and Veins
____ are the smallest veins, form when capillaries merge as they exit a capillary bed.
Postcapillary venules
Veins that are very porous, but with scattered smooth muscle fibers in the tunica media
Postcapillary venules
_____ form when postcapillary venules join. Although the walls of larger venules contain all three layers, they are still porous enough to allow white blood cells to pass.
Venules
_____ have walls with all three layers, but the tunica intima and tunica media are much thinner than in similarly sized arteries.
Veins
Many veins, especially those in the limbs, have valves, formed from folds of the tunica intima that prevent the backflow of blood. If these valves fail to close properly, _____ may occur.
varicose veins
These veins have few elastic or muscle fibers present and the wall consists primarily of a well‐developed tunica adventitia.
Veins
_____ is the organ that develops and implants in the mother’s womb (uterus) during pregnancy.
placenta
the unborn baby
fetus
The unborn baby is connected to the placenta by the _____
umbilical cord
All the necessary nutrition, oxygen, and life support from the mother’s blood goes through the placenta and to the baby through _____
blood vessels in the umbilical cord
The closure of the _____ and _____ completes the transition of fetal circulation to newborn circulation
ductus arteriosus and foramen ovale
Actual connection between the placenta and embryo, and later the fetus
Umbilical Cord
Formation of the placenta
Placentation
Area where the cord was attached becomes covered by a thin layer of skin, and forms a scar tissue
Umbilicus
Capillaries penetrate most body tissues with dense interweaving
networks called
capillary beds
Circulating blood bypasses the lungs and liver by flowing in different
pathways and through special openings called
shunts
This enriched blood flows through the umbilical vein toward the baby’s liver. There it moves through a shunt called
ductus venosus
In a fetal heart, most of the blood flows across to the left atrium through a shunt called the
foramen ovale
