Auricles
Flaps of hollow tissue located on the atria.
Atriovntricular valves
Located between the atria and the ventricles.
Semilunar valves
Entrances from the right ventricle to the pulmonary circuit of blood and then from the left ventricle to the systemic circuit.
Blood Flow
Inferior and superior vena cave to right atrium to tricuspid valve, to right ventricle, to pulmonary semilunar valve, to pulmonary trunk, to pulmonary arteries, blood returns from lungs through pulmonary veins and into the left atrium, through the bicuspi
Epicardium
Serous membrane madde of simple squamous epithelium overlying a thin layer of LCT. This layer lubricates the surface of the heart while beating.
Myocardium
Composed of cardiac muscle tissue. Thickness depends on the amount of force required to pump the blood.
Endocardium
Innermost lining of the heart which is composed of a layer of simple squamous epithelium.
Pulmonary circuit
Sends deoxygenated blood from the right ventricle into the lungs, returning oxygenated blood to the left side of the heart.
Systemic circuit
Sends oxygenated blood from the left side of the heart into all the rest of the body.
\
What is the pericardial sac composed of?
Parietal pericardium and fibrous pericardium
Parietal pericardium
Serous membrane that comes in direct contact with the epicardium.
Fibrous pericardium
Made of FCTf (dense irregular) making the sac very thick.
Fibrous skeleton
*Separates the atria from the ventricles
*Composed of FCT
*Blocks the electrical signals created by the atrium from passing to the ventricles
Right AV Valve (Tricuspid valve)
Between the right atrium and right ventricle. Opens into the right ventricle allowing blood to move in from the right atrium. When the ventricles contract the valve closes.
Chordae Tendinae
Strings of FCT that prevent the AV valves from opening backwards.
Papillary muscles
Muscular projection from the ventricles that attatch to the chordae tendinae.
Left AV Valve (Bicuspid valve)
Between the left atrium and left ventricle. Has only two flaps which ensure a tighter seal which is neeed because the left ventricle has to pump blood with great force into the systemic circuit.
Pulmonary Semilunar Valve
Found between the right atrium and the pulmonary trunk. Has three cusps which create a seal preventing the backward flow of blood. However, when the ventricular pressure is greater than the back pressure, the cusps will fold in half creating an opening in
Aortic Semilunar Valve
Found between the left ventricle and the ascending aorta. Same characteristics as in the previousle mentioned semilunar valve.
What are heart sounds created by?
The closing of the heart valves.
LUB
Lub is the first heart sound caused by the closing of the AV valves when the ventricles contract. At this point the semi lunar valves open (creating no sound).
DUP
Dup sound is created when the ventricles relax and the blood wants to flow backwards into the ventricles the AV valves then parachute open and seal the back entrance to the ventricles creating this particular sound.
Tunica Externa
Outermost layer made up of dense irregular FCT. This layer attatches the vessel to the deep fascia.
Tunica Media
Middle smooth muscle layer which enable the vessel to dialate and constrict.
Tunica Interna
Made of endothelium (simple squamous epithelium). The cells creat a very smooth surface which reduces the friction of the blood as it passes through the vessels.
Elastic arteries
Very wide diameter, they have all three layers. The t. media is modified to contain a lot of elastic fiebers that allow too much strectching to recieve large volumes of blood.
Muscular arteries
Narrower than elastic arteries (brachial artery and femoral artery). Exhibit all three layers , tunica media is well developed with much smooth muscle, tunica interna appears pleated because it is unable to contract during vaso constriction.
Arterioles
Verry narrow diameter. Poorly defined tunica externa. T. media is discontinous, reduced to circular bands found around the t. intima.
Capillaries
So narrow that blood cells must move through in a sigle file. But this is of benefit because this is where exchange of oxygen and carbon dioxide occurs (in capillary beds). Only exhibit a tunica intima.
Continous Capillaries
Most common type of capillary . Made of a continous layer of endothelium with simple squamous cells that are connected by tight junctions and desmosomes.
Fenestrated Capillaries
Pourous endothelium. There appear to be small holes that pass through the SS cells. Allows very rapid movement of materials accross the capillary. Found in the kidney and choroird plexuses of the brain.
Sinusoid
Most pourous. Broken endothelium. Found in organs where blood pools for maximum absorption and secretion. Not found in the small intestine. Some venuoles lack t. intima and media entirely.
Venuoles
Similar to arterioles. Soma may lack t media and externa. May appear as large capillaries.
Mid-sized veins
Exhibit all three layers, but the t. media is reduced and t. externa is essentially the thickest. Exhibit one way valves to aid in the movement of blood back into the heart.
Large Veins
Exhibit all three layers; t. media is thicker that mid-sized veins but much thinner than the muscular arteries. T externa is relatively the thickest. Exhibit one way valve to aid in the movement of bloof back into the heart.
Factors that contribute to the forward movement of blood in the arterial blood vessels
1. Force of the ventricle during contraction
2. Elastic recoil of hte walls of the arteries when the ventricle relaxes.
What are two ways that blood arrives at the brain?
Through the internal carotid arteries and the vertebral arteries.
Internal Carotid Arteries
Pass through the carotid canals in the skull and enter the brain inferior and laterally , attatching the the cerebral arterial cirlcle. Which then disperses blood to all areas of the brain, but primarily the anterior region.
Vertebral Arteries
Pass through the transverse foramina of the cervical vertebra entering the cranium throught the foramen magnum. Vertebral arteries join together to form the basilar artey which give rise to some arteries that enter through the posterior of the brain. The
Factors that aid in the movement of blood back to the heart though veins
*Venou one-way valves, similar to semilunar valves in anatomy, direct blood toward the heart.
*Constriction and relaxation of the t. media in the medium and large veins
*Pressure applied to the veins and venules when we move our muscles
*Respiratory pump:
Blood Reservoir
Anywhere in the CVS where blood will pool and move very slowly.
What is the body's largest blood reservoir?
Veins. Also organs that exhibit sinuses such as the liver and the spleen.
Which veins drain into the hepatic portal vein?
The mesenteric, gastric and splenic.
Hepatic Portal Vein
Carries all of the blood directly into the liver before it enters general circulation.
Portal Vein
Any vessel that connects two capillary beds. Very rare in the body. Found between the abominal digestive organs and the liver, in the pituitary gland and in the kidney.
Why is the hepatic portal system significant?
Because it allows the liver to regulate and maintain a constant amount of nutrients in the blood stream.
Liver Blood Flow
TOWARD
*Hepatic portal vein and hepatic artery
AWAY
*Hepatic vein drains the blood from the iver into the inferior vena cava, after the liver has had a chance to regulate concetration of nutrients, detoxify toxins, etc.
Foramen Ovale
Is a hole in the arterial septum, between the right and left atrium. Allowing for blood exchange between the two. At birth becomes fossa ovale.
Ductus Arteriousus
Is a vessel that connects the pulmonary trunk with the aortic arch, thus sendig much of that blood that is going to the lungs directly into the systemic circulation. At birth it becomes ligamentum arteriosum.
Ductus Venosus
Is a vessel that allows blood to bypass the fetal liver and go directly to the inferior vena cava. This is present because the mother is doin the work. At birth the umbilical cord is cut off and this will become a round ligament that runs between the righ