1

Lab 4

• Anatomy of Arteries, Veins and Capillaries

• Identification of major blood vessels

• Blood Flow

• Lymphatic System

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Figure 19.2

Large veins(capacitancevessels)

Largelymphaticvessels

Arteriovenousanastomosis

Lymphaticcapillary

Postcapillaryvenule

Sinusoid

MetarterioleTerminal arteriole

Arterioles(resistance vessels)

Muscular arteries(distributingvessels)

Elastic arteries(conductingvessels)

Small veins(capacitancevessels)

Lymphnode

Capillaries(exchange vessels)

Precapillary sphincterThoroughfarechannel

Lymphaticsystem

Venous system Arterial systemHeart

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Figure 19.1b

Tunica media(smooth muscle andelastic fibers)

Tunica externa(collagen fibers)

LumenArtery

LumenVein

Internal elastic lamina

External elastic lamina

Valve

(b)

Endothelial cellsBasement membrane

Capillarynetwork

Capillary

Tunica intima• Endothelium• Subendothelial layer

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Table 19.1 (1 of 2)2/6/2010 4M. Dufilho

Table 19.1 (2 of 2)2/6/2010 5M. Dufilho

Figure 19.6

Systolic pressure

Mean pressure

Diastolic pressure

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Factors Aiding Venous Return

1. Respiratory “pump”: pressure changes created during breathing move blood toward the heart by squeezing abdominal veins as thoracic veins expand

2. Muscular “pump”: contraction of skeletal muscles “milk” blood toward the heart and valves prevent backflow

3. Vasoconstriction of veins under sympathetic control

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Figure 19.7

Valve (open)

Contractedskeletalmuscle

Valve (closed)

Vein

Direction ofblood flow

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Blood Pressure

• What is blood pressure?

• How is it measured?

• Where is it measured?

• Systolic vs. Diastolic?

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Lymphatic System

• Consists of three parts

1. A network of lymphatic vessels (lymphatics)

2. Lymph

3. Lymph nodes

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Lymphatic System: Functions

• Returns interstitial fluid and leaked plasma proteins back to the blood

• Once interstitial fluid enters lymphatics, it is called lymph

• Together with lymphoid organs and tissues, provide the structural basis of the immune system

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Figure 20.2a

Cervical nodesEntrance of rightlymphatic duct into vein

Internal jugular vein

Entrance of thoracicduct into vein

Thoracic duct

Cisterna chyli

Lymphaticcollecting vessels

Axillary nodes

Aorta

Inguinal nodes

Regionallymph nodes:

(a) General distribution of lymphatic collecting vessels and regional lymph nodes.

Drained by the rightlymphatic ductDrained by thethoracic duct

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Figure 20.1

Lymphaticsystem:Lymph ductLymph trunkLymph node

Lymphaticcapillary

Bloodcapillaries

Lymphaticcollecting vessels, with valves

HeartArterial systemVenous system

Tissuefluid

Tissue cell Bloodcapillaries

Lymphaticcapillaries

(a) Structural relationship between a capillary bed of the blood vascular system and lymphatic capillaries.

Filaments anchoredto connective tissue

Fibroblast in looseconnective tissue

Endothelial cell

Flaplike minivalve

(b) Lymphatic capillaries are blind-ended tubes in which adjacent endothelial cells overlap each other, forming flaplike minivalves.

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Figure 20.2b

Left jugular trunk

Internal jugular veins

Left subclavian trunk

Left subclavian vein

Esophagus

Trachea

Left lumbar trunk

Left bronchomediastinaltrunk

Entrance of thoracicduct into vein

Thoracic duct

Hemiazygos vein

Intestinal trunk

Inferior vena cava

Right jugular trunk

Right lymphatic duct

Right subclavian trunk

Right subclavian vein

Right broncho-mediastinal trunkBrachiocephalic veins

Superior vena cava

Azygos vein

Cisterna chyli

Right lumbar trunk

(b) Major lymphatic trunks and ducts in relation to veins and surrounding structures. Anterior view of thoracic and abdominal wall.

Ribs

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Lymph Transport

• Lymph is propelled by

• Pulsations of nearby arteries

• Contractions of smooth muscle in the walls of the lymphatics

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Lymph Nodes

• Principal lymphoid organs of the body

• Embedded in connective tissue, in clusters along lymphatic vessels

• Near the body surface in inguinal, axillary, and cervical regions of the body

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Figure 20.4a

Afferent lymphaticvessels

Efferent lymphaticvessels

CapsuleTrabeculae

Hilum

Cortex• Lymphoid follicle• Germinal center• Subcapsular sinus

Medulla:• Medullary cord• Medullary sinus

(a) Longitudinal view of the internal structure of a lymph node and associated lymphatics

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Figure 20.2a

Cervical nodesEntrance of rightlymphatic duct into vein

Internal jugular vein

Entrance of thoracicduct into vein

Thoracic duct

Cisterna chyli

Lymphaticcollecting vessels

Axillary nodes

Aorta

Inguinal nodes

Regionallymph nodes:

(a) General distribution of lymphatic collecting vessels and regional lymph nodes.

Drained by the rightlymphatic ductDrained by thethoracic duct

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Copyright © 2010 Pearson Education, Inc.

Figure 20.5 Lymphoid organs.Tonsils (in pharyngealregion)

Thymus (in thorax; mostactive during youth)

Spleen (curves aroundleft side of stomach)

Peyer’s patches(in intestine)

Appendix

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