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Flashcards in CV histo week 1 Deck (43)
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1

The cardiovascular system is the transport system that carries blood and lymph to and from the tissues of the body. What are its components?

hear, blood vessels, and lymphatic vessels

2

In the capillary beds, there is two directional exchange of fluid called ____ ____ where oxygen, CO2, metabolites, and waste are exchanged.

blood filtrate

3

Describe the pattern of lymph drainage. 

Fluid that escapes from the capillary bed goes into lymph capillaries and is returned to the blood by coursing into larger and larger lymphatic vessels that evetullay drain into veins of the neck. 

4

What vessels do WBCs leave circulation to go into tissues?

venules

5

True or false: Each organ has a patterns or blueprint for blood flow which is characteristic for that organ. (liver, spleen, kidney, etc.)

True.

6

What is the composition and function of the fibrous skeleton of the heart?

It is composed of dense irregular CT. It provides attachment sites for the leaflet of all four valves of the heart (aortic, pulmonic, tricuspid, mitral). Also provides attachment for the myocardium. Extends into the membranous portion of the interventricular septum where it lies adjacent to a portion of the conduction system. Also acts as an electrical insulator by preventing flow of electrical impulses btwn atria and ventricles. 

7

What is included in the impulse conduction system of the heart? What are these parts made of? What are they controlled by?

1. made up of the SA node, AV node, bundle of His, right and left bundle branches, Purkinje fibers

2. highly specialized cardiac muscle cells NOT NERVE CELLS!

3. regulated by the autonomic nervous system

8

What are the 3 layers of the heart and what are their compositions?

From outside in: epidcardium, myocardium, endocardium

epicardium: outermost layer of mesothelial cells (simple squamous epithelium), small amount of CT, blood vessels (coronary arteries for example), nerves, fat

myocardium: cardiac muscle and accompanying CT, specialized fibrous skeleton in certain locations

endocardium: fibroelastic CT in a loose arrangement, impulse conduction system elements (in certain locations), innermost layer is endothelium (simple squamous epithelium) facing the lumen of each chamber and covering the valves as well, may include bundles of Purkinje fibers

9

10

True or false: The contraction of cardiac muscle is vigorous, rhythmic, and under the contol of both the ANS and circulating hormonse. The structrual arrangment of intercalated discs allows the heart to contract in a wringing fashion. 

True. 

11

What is the flow of blood through the varying sizes of arteries and veins?

Blood flows from the heart into large (elastic) arteries that lead to muscular (distributing) arteries and then to arterioles. Capillary beds vary in permeability and have some specializations for exchange properties. Blood enters the venous side by passing into venules (also sites for exchange) and then into veins of increasing size. 

12

What are the 3 layers/tunics of vessels?

Tunica intima

Tunica media

Tunica adventicia

13

What is located in the tunica intima, tunica media, and tunica adventicia?

tunica intima: endothelium linging with its basal lamina. Adjacent, a subendothelial layer consisting of loose CT. In arteries and arterioles, there is also an internal elastic lamina which is a sheetlike lamina of fenestrated elastic membrane.

tunica media: Contains circumferentially arranged smooth muscle cells. Also contains collagen, elastin, reticular fibers (type III collagen) and proteoglycans interwoven with the smooth muscle. Arteries have organized layers of elastic fibers in the tunica media. The fenestrations in these sheets of elastic allow for passage of molecules and can house bundles of smooth muscle interwoven within this layer. The boundaries of the tunica media in an artery extend from the internal elastic membrane to the exernal elastic membrane. This layer is larger in arteries than in veins. 

tunica adventicia: longitudinally arranged collagenous tissue with elastic fibers. These CT elements wil erge with the CT surrounding the vessel. In large vessels, this layer contains the vasa vasorum (vessels contained within the wall of a vessel) and nervi vascularis (nerve fibers in the wall of a vessel). In veins, this layer is thicker than the companion artery and in large veins, smooth muscle may be present in this layer. 

14

What are the types of vessels?

15

What are some features of large elastic arteries? Name one example in the body.

Aorta is a large elastic artery. 

features:

-relativley thick tunica intima

-thick tunica media with prominent elastic laminae

-tunica adventitia with vasa vasorum and nervi vascularis

please see pg 85 of course notes for another pic

16

What are some features of muscular arteries? Where are they found in the body?

Most arteries are muscular arteries.

features:

-thinner tunica intima (than elastic arteries)

-prominent internal elastic lamina

-thick tunica media

-external elastic lamina (sometimes visible)

17

What are some features of arterioles?

Arterioles regulate flow to capillary beds.

-have only 1-2 layers of smooth muscle in the tunica media 

-very thin tunica intima

-no internal elastic lamina

-thin tunica adventicia

see pg 87 of course notes for another pic

18

What are features of capillaries?

-lumen is typcially 8-12 micrometers in diameter and permits only a single RVC to maneuver through the lumen at a time

-vessel wall is a simple tube comprised of endothelium and basal lamina (tunica intima)

-may have a tunica media comprised of a pericyte

19

What is a pericyte?

  • CT cell that is similar to mesenchymal cells
  • surrouds capillary endothelium within the basal lamina providing physical stability
  • has contractile ability
  • participates in physical and chemical signaling within the endothelium
  • may give rise to endothelial cells and smooth muscle cels during wound healing (angiogenesis)

20

What are the 3 types of capillaries and where in the body are they typically found?

1. continuous capillary: fat, muscle, lung, nervous system (CNS)

2. fenestrated capillary: intestinal vili, endocrine glands, kidney glomeruli

3. discontinuous/sinusoidal: liver, bone marrow, spleen

21

What are the features of continuous capillaries?

  • numerous pinocytic vesicles
  • tight junctions
  • located in muscle, lung, CNS, fat

22

What are features of fenestrated capillaries?

  • less pinocytic veislces than continuous (bc have fenstrations)
  • may have diaphragms across fenestrations
  • locations include endocrine glands, GI tract, kidney glomeruli

23

What are features of sinusoidal capillaries?

  • large diameter lumen
  • spaces btwn endothelial cells
  • incomplete basal lamina
  • locations include spleen, liver, bone marrow

24

How is the flow through microvessels controlled? What is the effect of vasodilating agents on aterioles and what effect does this have on capillaries?

Flow through the microvessel network is under local and systemic control. Arterioles respond to vasodilating agents (NO, O2) by relaxation of smooth muscle and results in increased flow. This increased pressure within the capillary drives plasma into the surrounding tissue resulting in edema. 

25

How is blood flow to capillaries locally controlled as it pertains to AV shunts and metarterioles? Why may AV shunts be used?

Arteriovenous anastamosis (shunt) is a communication btwn an artery and a vein. Allows blood to bypass capillary circulation. Serves as function of phasic activity of an organ. When active, AV shunts are close and blood circulates through capillaries and are open when organ is inactive in order to bypass the capillary bed. Also used for temperature regulation in shunting heat away from skin to conserve for organs. 

Metarterioles are preferential thoroughfares (way or place for passage, main road) in capillary beds. Smooth muscle sphincters called capillary sphincters are located on the origin of capillaires coming off of metarterioles. Blood flow to capillaries is controlled by these sphincters. 

26

What are features of veins?

Have walls with tunics but layers are not as distinct or as well defined as arteries. When compared to accompanying arteries, veins have the following features:

  • veins have a larger lumen
  • have thinner walls (much less t. media)
  • often are irregular or collasped

27

Capillaries--->post-capillary venules--->venules--->small/medium veins---> large veins---> heart

28

What is the fxn and composition of post-capillary venules? What chemicals act here and what are their effects? What process occurs here? What are the features?

  • receive blood from capillaires
  • endothelium is the site of action for histamine and serotonin which results in:
    • 1. exit of fluids into tissue from these vessels
    • 2. extravasation of WBCs into tissue from these vessels
    • in lymph nodes, post-capillary venles are the sites of migration of lymphocytes
  • lumen is 10-15 micrometers in diameter
  • wall is a simple endothelial tube-T. initma
  • may have a T. media comprised of a pericyte (no smooth muscle)

29

What are the features of venules?

  • lumen up to 100 micrometers in diameter
  • very thin wall-t. intima
  • no smooth muscle (no T. media)
  • look like dilated capillaries, T. adventicia blends in

30

What are features of small to medium veins? (note that most veins are of this type)

  • lumen diameter up to 10 mm
  • T. media has smooth muscle, elastic and collagen fibers
  • T. adventicia is thicker than the media and has network of collagen and elastic fibers. blends in with surrounding CT.