Blood Vessels Flashcards

1
Q

Identify

A

Right ventricle with epicardium, cardiac muscle, and endocardium

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2
Q

Identify

A

Epicardium: covers surface of heart (same thing as visceral layer of pericardium). Composed of mesothelium and has a layer of loose CT (with nerves, fat, and BV)

Myocardium: thickest layer of heart wall (thicker in ventricles than atria), composed of cardiac musce

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3
Q

Identify

A

Purkinje fibers - right above endocardium

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4
Q

Identify

A

Coronary sulcus and valve

Coronary artery with sclerosis

Chordae tendinae next to valve - prevent valves from turning inside out

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5
Q

Identify

A

Aorta

Arrow marks boundary between tunica media and tunica adventitia

Vaso vasorum seen in adventitia

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6
Q

Tunica intima

A

Innermost layer surrounding blood vessels (continuous with endocardium)

Has endothelium, basal lamina, and a layer of loose CT

In arteries, an internal elastic layer (IEL) is seen between the intima and media. Fenestrated layer of elastin

Fx: permeable/semipermeable barrier

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7
Q

Tunica media

A

Middle layer surrounding blood vessels

Composed of smooth muscle, elastic fibers and lamellae, reticular fibers, and proteoglycans

Larger vessels have an external elastic lamina (EEL) between media and adventitia

Fx: controls diameter, blood pressure, and blood movement

Picture shows border between media and adventitia

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8
Q

Tunica adventitia

A

Outermost layer surrounding blood vessels (continuous with epicardium)

Composed of fibroblat, type I collagen, and elastic fibers

Large blood vessels have vaso vasorum - provides nutrients to vessel wall via small vessels

*Veins have more vaso vasorum (because of low nutrient and O2 content of blood)

Fx: support, attaches vessels to tissue, carries vessels and nerves

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9
Q

Identify

A

Aorta on right

Inferior vena cava on left

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10
Q

Large elastic artery

A

Ex. aorta, common carotid, brachiocephalic, subclavian, pulmonary arteries, elastic arteries

Intima: endothelium (cells connected by occluding jxns, cells contain Weibel-Palade bodies), about 1/6 thickness of wall., No clear IEL

Media: 40-70 layers of fenestrated elastic lamella with smooth muscle cells dispersed between. Thin EEL and some vaso vasorum from adventitia

Adventitia: thin, has nerve fibers, lymphatics, and vaso vasorum in loose CT

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11
Q

Mixed musculo-elastic arteries

A

Transitional between large and medium arteries

Tunica media and adventitia about the same thickness

More obvious IEL

Fewer elastic lamellae (squiggles)

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12
Q

Medium muscular arteries

A

Ex. coronary, renal, mesenteria, brachial, femoral

Fx: distribute blood to organs and tissues, regulated by ANS control of media

Intima thin, prominent IEL

Media thick, many concentric layers of smooth muscle cells, EEL in big diameter speciment (goes away with smaller diameter)

Adventitia may be as thick as the media, poorly developed vaso vasorum and lymphatics

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13
Q

Arterioles

A

<100 microns in diameter (invisible to naked eye)

Fx: maintain normal BP in arterial system, reduce pressure of blood entering capillaries

Intima thin layer of reticular fibers, no IEL in really small arterioles

Media 1-5 layers of smooth muscle

Adventitia moderate to none

Terminal segment before capillary bed is a metarteriole (precapillary sphincter) that regulates blood into capillary

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14
Q

Change in arteries with age

A

4th month in utero: 3 tunics compelte

Largest arters grow until age 25

After 30: media stiffens (increase in elastic lamellae (see pic), deposition of collagen and proteoglycans)

  • Large elastic change more than large muscular. Plaques can form in intima (foam cells). See pic
  • Muscular arteries: calcification of media, also develop plaques that reduce intimal diameter
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15
Q
A
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16
Q

Identify

A

Muscular artery

Tunica mediated is contracted, giving the IEL a scalloped appearance

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17
Q

Identify

A

Muscular artery

Tunica intima, IEL, Tunica media, EEL, Tunica adventitia

18
Q

Identify

A

Vein (in submucosa of ileum)

19
Q

Identify

A

Capillary

Venule

20
Q

Identify

A

Venule filled with blood

Arteriole

21
Q

Identify

A

Very small venule with two RBC in lumen

22
Q

Identify

A

Venule and arteriole

Mast cell in center

23
Q

Identify

A

Venule

Arteriole

Capillaries

24
Q

Identify

A

Lacteals (small lymphatic capillaries) in duodenum of monkey

25
Identify
1. Venules 2. Lymphatic vessels
26
Enothelial cells
Joined by tight and gap junctions Cytoplasm supported by intermediate filaments desmin and vimentin, Life span ~ 150-180 days (slowly renewing) Secrete a basal lamina, Type 1,3,4,5 collagens, fibronectin, laminin, coagulants, anticoagulants
27
Pericytes
- Stellate cells that surround capillaries and some venules - Extensive branching process **- Share the basal lamina **of the endothelial cell - Some can contract and regulate blood flow - Can serve as stem cells for endothelial and smooth muscle cells after injury
28
Continuous capillaries
- The most common of three types - Found in muscle, nervous, and CT tissues; pancreas - Complete endothelial lining (sealed by tight junctions - permit passage of small molecules) and basal lamina - Cytoplasm has vesicles to transport large molecules
29
Three types of capillaries
1. Continuous capillaries 2. Fenestrated capillaries 3. Sinusoids
30
Fenestrated capillaries
- Found in the pancreas, intestines, endocrine glands (special type without a diaphram found in renal glomerulus) - Contunous but THIN endothelium and basal lamina. Endothelial cells have small pores (fenestrations) that are covered by a diaphgragm - Specialized for rapid interchange of substances between blood and tissue
31
Sinusoids
- Irregular blood channels that conform to shape of structure they are in 1. **S****inusodial capillaries** (endocrine): continuous lamina and fenestrae with diaphragms that are much larger than fen. capillaries 2. **Discontinuous sinusoids** (liver and bone marrow): discontinuous or absent basal lamina, large gaps between endothelial cells - permits enhanced exchange between blood and tissue 3. **Venous sinusoids** (spleen)
32
Veins vs. Arteries
- Veins have greater v**ariation in size/structure** - Veins **hold more blood**, more **numerous** in body - Veins have more **extensive vaso vasorum and lympathics** - Veins have **more** **collagen** and **less elastic substance and smooth muscle** - Veins **thickness** comes mostly from **adventitia** - Veins have **valves**
33
Large veins
Ex. superior and inferior vena cava, portal vein **Intima**: continuous endothelium and basal lamina, no IEL **Media:** incomplete or absent **Adventitia: **largest, best developed tunic, forms 95% of thickness of the vessel wall. Thick bundles of smooth muscle, collagen, elastic fibers. Well-developed vaso vasorum and lymphatics
34
Small and Medium Veins
**Intima: **continous endothelium and basal lamina, complete IEL only in legs, some valves **Media: **poorly developed except in limbs **Adventitia:** thickest tunic, usually no smooth muscle. Contain collagen and elastic fibers, fibroblasts, lymphatics, and vaso vasorum
35
Venules
Fx: exchange of materials (started in capillaries). Become leaky in response to histamine and serotonin. Site of leukocyte emigration **Pericytic venules:** post-capillary, resemble large capillaries, have a pericyte **Muscular venules: **receive blood from pericytic venules. Media has 1-2 circular layers of smooth muscle. Thin adventitia of loose CT
36
Portal systems
Carry blood from one capillary bed to another Ex. Hepatic portal vein between intestines and liver, hypophyseal portal veins of pituitary
37
Arteriovenous anastomoses
Direct cross connections between arterioles and venules Smooth muscle cells form sphinchter that regulates blood flow and allows a bypass of a capillary bed
38
Lymphatic vesicles
1. Large lumens 2. Thin walls 3. Irregular shape 4. Extensive branching, parallel to blood capillaries and veins - Similar structure to veins but more irregular in shape/size - Discontinuous or absent basal lamina, held open by elastic anchoring filaments Fx: collect lymoh from EC spaces and return to blood vascular system, aid in circulation of lymphocytes
39
Physiological significance of elastic lamina in arterioles
Helps smooth out pressure differences with distance from the heart
40
Weibel-Palade
Storage granules of endothelial cells In intima of large elastic arteries