Term
| What do "great vessels" of circulation include? |
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Definition
1. Large elastic arteries (aorta+major branches)
2. Pulmonary Trunk/Arteries and Veins
3. Inferior Vena Cavae-blood returning to heart from lower body
4. Superior Vena Cavae- blood returning to heart from upper body |
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Term
What is the Heart?
pump
circuits
chambers |
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Definition
a muscular double pump
1. pulmonary circuit- blood to and from lungs
2. systemic circuit- vessels transport blood to and from body tissues
4 chambers
-2 atrai receive blood from circuits
-2 ventricles- pumping chambers of heart |
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Term
| What do blood vessels begin as in the embryo? |
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Definition
| as condensations of mesodermal mesenchyme |
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Term
| Describe the embryonic heart at days 21 and 22 |
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Definition
Pair fo tubes fuse at day 21
heart starts pumping at day 22
Bulges develop along heart tube |
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Term
| What are the earliest heart chambers in the embryo? |
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Definition
1. sinus venosus- RA and determine HR
2. Atrium
3. Ventricle
4. Bulbus cordis- becomes great arteries: aorta and pulmonary |
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Term
| During embryonic heart development, the heart bends: |
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Definition
into an S shape
Atria brought to top, septa divide atria/ventricles |
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Term
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Definition
largest organ of the mediastinum
Between the lungs
apex is directed out (toward sternum) and 45 degrees, and left about 45 degrees |
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Term
| What are the 4 corners of the heart? |
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Definition
1. superior right- 3rd rib at costal cartilage/sternum
2. inferior right- 6th rib about 1.5 inch lateral to sternum
3. superior left- 2nd rib at costal cartilage, 1.5 in from sternum
4. inferior left- lies in 5th intercostal space at midvlavicular line |
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Term
| What are the coverings of the heart? |
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Definition
Pericardium=
-fibrous pericardium- strong dense CT
-Serous pericardium- formed from two layers:
-parietal
-visceral |
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Term
| What are the layers of the heart wall? |
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Definition
1. Epicardium- visceral layer of the serous pericardium=serosal membrane (simple squamous epithelium+thin CT)
2. Myocardium- cardiac muscle arranged in circular/spiral patterns
3. Endocardium- endothelium resting on a layer of loose CT (lines inner walls) |
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Term
| How do the heart walls differ in thickness? |
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Definition
atria-thin
ventricles-thick
left ventricle- 3X thicker than right**
--exerts more pumping force flattens RV into crescent shape |
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Term
| What is the internal division between the 2 atria? and the 2 ventricles? |
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Definition
interatrial septum
interventricular septum |
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Term
| Where does the blood go that is oxygen poor in the superior and inferior vena cavae? |
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Definition
Pulmonary circuit
RA, RV, pulmonary trunk/arteries-> lungs |
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Term
| Where does the blood go that is oxygen rich in pulmonary veins? |
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Definition
systemic circuit
LA, LV, aorta, distributing arteries |
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