Histology Exam 2 - Cardiovascular

Front 1

The cardiovascular system is responsible for...

Back 1

The transport and homeostatic distribution of:
-oxygen
-nutrients
-body fluids and solutes
-body heat
-immune system components

Front 2

4 Parts of the Cardiovascular System:

Back 2

1. Heart - muscular pump
2. Arteries - carry blood away from the heart and to tissues
3. Veins - carry blood from the tissues to the heart.
4. Capillaries - between arteries and veins, site of exchange between blood and tissue.

Front 3

The Lymphatic Vascular System

Back 3

Set of vessels that move lymph in one direction - toward the junction of the lumpy vessels within the jugular and subclavian veins.

Front 4

3 Parts of the Lymphatic Vascular System:

Back 4

1. Capillaries - blind ended tubes that collect lymph from tissues.

2. Vessels - collect lymph from lymphatic capillaries.

4. Ducts - collect lymph from vessels and empty into the large veins of the neck.

Front 5

[Circulatory System] Wall Structure - 3 Tunics:

Back 5

Tunica Intima
Tunica Media
Tunica Adventitia

Front 6

Tunica Intima

Back 6

Innermost, bordering on the lumen.

Consists of:
-endothelium (squamous epithelium w/ basement membrane)

-subendothelial layer (connective tissue layer)

-internal elastic lamina (fenestrated layer of elastin)

Front 7

Tunica Media

Back 7

Middle layer.

Consists of:
-vascular smooth muscle fibers (mainly circumferentially arranged. Arteries are thicker media).

-external elastic lamina (layer of elastic fibers between tunica media and adventitia.

Front 8

Tunica Adventitia

Back 8

Outermost layer, mostly type I collagen and elastic fibers that anchor in the surrounding tissue.

-In veins is the thickest layer - large ones may contain bundles of longitudinal muscle fibers.

-Large vessels may contain VASA VASORUM (vasculature of the vessels) and NERVI VASCULARIS (control contraction of smooth muscle).

Front 9

Types of Arteries

Back 9

Elastic
Muscular
Arteriole
Metarteriole

Front 10

Elastic Arteries

Back 10

Large arteries
-Are often considered organs
-Stretch in systole due to elastic fibers
-Contract in diastole due to elastic fibers. Therefore they help maintain constant pressure.

Front 11

Intima [elastic arteries]

Back 11

Thicker than muscular arteries
-endothelium lies on thin basal lamina
-porous internal elastic lamina.

Front 12

Media [elastic arteries]

Back 12

Lots of concentrically arranged elastin
-Circumferentially arranged smooth muscle fibers between elastic layers.
-Muscle cells interwoven with reticular fibers (type III collagen).

Front 13

Adventitia [elastic arteries]

Back 13

Thin relative to the diameter of the vessel.
-Contains type I collagen
-Has external elastic lamina.

Front 14

Muscular Arteries

Back 14

Medium
-Common in many tissues and organs.
-Major distribution branches of elastic arteries.
-Includes named arteries of the limbs (ex. branchial) and of the abdominal cavity (ex. superior mesenteric)

Front 15

Intima [muscular arteries]

Back 15

Contains typical endothelium and subendothelial connective tissue.
-A prominent internal elastic lamina looks like a refractive wavy line between the intima and media.

Front 16

Media [muscular arteries]

Back 16

Relatively thick (up to 40 layers of smooth muscle).
-Interspersed with variable amounts of collagen, elastic fibers and proteoglycans.

Front 17

Adventitia [muscular arteries]

Back 17

Relatively thin and contains mostly collagen fibers (loose connective tissue).

Front 18

Arterioles

Back 18

Small arterial vessels.

Front 19

Intima [arteriole artery]

Back 19

Has typical endothelium
-Endothelium may contain rod-shaped Weibel-Palade granules.
-Often sub endothelial connective tissue and inner elastic lamina are missing.

Front 20

Media [arteriole artery]

Back 20

Has 1-5 layers of smooth muscle wrapped circumferentially around lumen.

Front 21

Adventitia [arteriole artery]

Back 21

Very thin and composed of collagen fibers.

Front 22

Metaterioles

Back 22

Small branches of arterioles.
-Endothelium surrounded by incomplete, single layer of smooth muscle cells.
-Constriction of smooth muscle gates monitor flow into capillaries.
-Can't completely halt flow of blood into capillaries.

Front 23

Precapillary Sphincters

Back 23

Ring of smooth muscle fibers surrounding the metarterioles where capillaries originate.
Therefore, contribute to monitoring flow into capillaries.

Front 24

Capillaries

Back 24

-Made up mostly of epithelial cells.
-Pericytes or Adventitial cells (mesenchyme cells) scattered along their length.
-Capillary bed: profusion of anastomosing channels.

Front 25

3 Types of Capillaries

Back 25

1. Continuous
2. Fenestrated
3. Sinusoidal

Front 26

Continuous Capillaries

Back 26

Smooth endothelial cell lining with tight junctions (ex. muscles, brain, peripheral nerves).

Only allow small molecules, like water and ions to diffuse through tight junctions which leave gaps of unjoined membrane which are called INTERCELLULAR CLEFTS.

Front 27

Fenestrated Capillaries

Back 27

Endothelial cells perforated by pores (fenestra). (ex. kidney, intestines).

Allow small molecules and limited amounts of protein to diffuse

Front 28

Sinusoidal Capillaries

Back 28

Ex. liver, bone marrow, spleen
-Have unusually wide lumens
-Follow a tortuous path through tissues.
-Have distinct gaps in endothelium large enough for cells to pass through.
-Have many fenestrations in the endothelial cells.
-Often have reticuloendothelial cells between endothelial cells.
-Have a discontinuous basal lamina.

Allow larger molecules including red and white blood cells.

Front 29

Transport Across Capillaries (4 ways):

Back 29

1. Through fenestra
2. Through clefts
3. Pinocytosis - movement by vesicles.
4. Diapedesis - migration of leukocytes through an endothelium. May involve interaction between cells, histamine release, etc.

Front 30

Large Veins

Back 30

superior and inferior vena cava

Front 31

Intima [large veins]

Back 31

Well developed with thick sub endothelial connective tissue.
Extensions of the intima form the VALVES.

Front 32

Media [large veins]

Back 32

Several layers of smooth muscles, abundant collagen and reticular fibers and sparse elastin.

Front 33

Adventitia [large veins]

Back 33

Thickest layer, collagen and longitudinal smooth layer.

Front 34

Small and Medium Veins

Back 34

Similar to large but have smaller diameters, thinner walls, fewer valves, and little if any muscle.

Front 35

Venules

Back 35

Smaller version of veins but have no valves

Front 36

Arteriovenous Anastomoses

Back 36

Direct connect between arteries and veins. Blood flow is regulated by smooth muscle in intervening vessels. Therefore, when it is open blood can bypass the capillary bed. Connections between arterioles an venules (termed GLOMERA) occur in finger pads, nail beds and ears.

Front 37

Heart (setup)

Back 37

Ventricles and Atriums (left right)
Atriums up top, Ventricles on the bottom.

Front 38

Tunics of the Heart

Back 38

Endocardium
Myocardium
Epicardium

Front 39

Endocardium

Back 39

Homologous to intima, has three components:

1. Endothelium - underlain with basal lamina

2. Subendothelial connective tissue with elastic fibers and smooth muscle cells.

3. Subendocardrial - layer of loose connective tissue containing small blood vessels and nerves.

Front 40

Myocardium

Back 40

Homologous to media,
-Made up mostly of cardiac muscle, each muscle fiber surrounded by an endomysium and fascicles surrounded by perimysium.

Front 41

Epicardium

Back 41

a SEROSA composed of:
-A layer of mesothelial cells.
-A thin basal lamina
-A layer of subepicardial connective tissue (areolar tissue) binding the epicardium to the myocardium.