Circulatory System

Lymphatic System

Return fluids and cellular debris from the interstitial space of tissues to regular cardiovascular circulation

Cardiovascular Sytem

Circulate blood to transport nutrients, oxygen, CO2, hormones

Capillary Beds 

Gas exchange occurs, nutrients are delivered, and metabolic waste is picked up.

Left Side of Heart

Systemic Circulation

Right Side of the Heart

Pulmonary Circulation

Artery

From the heart to tissue with high pressure

Veins

From tissue to the heart with low pressure

Vessel Layers

Tunica intima, tunica media, tunica adventitia

Tunica Intima

Single layer epithelial cells + CT

Diffusion of Blood

Arteries with high pressure force blood to go through arterioles and eventually the capillary bed to transmit blood to veins with low pressure (nutrient and gas exchange in tissue)

Tunica Media

Smooth Muscle (arteries bigger than veins)

Tunica Adventitia

CT (externa)

Large (Elastic) Artery

Near the heart can withstand high pressure. Allows for expansion and then recoil of blood to flow slowly into the system.

Muscular (distributing) Arteries

Move blood towards arterioles and regulates flow of blood to the body via the large tunica media (vasoconstriction or vasodilation).

Arteriole (small) Arteries

Push blood into the capillary bed

Thoroughfare (Metarteriole)

Main branch of blood movement from arteriole to venule.

Capillary Sphincters

Rings of SM from metarteriole to capillaries, permitting or denying access.

Arteriovenous Anastomosis

Completely bypasses the capillary bed, allowing for the movement of blood from an arteriole to venule. 

Venule

Little to no tunica media collecting blood from capillary beds. 

Medium Veins

A few smooth muscle cells contain venous valves with a large lumen (Facial v., internal jugular v.)

Large Veins

Thick tunica adventitia strengthened by SM with less elastin in walls (Vena Cava)

Vein Function

Flow from superficial to deep with valves that prevent backflow, using skeletal muscle to pump blood against gravity.

Varicrose Veins

Failure of valves 

Vasculogenesis

Embryonic formation of blood vessels

Angiogenesis

Formation of new capillaries by sprouting new routes or splitting existing capillaries. Constant normal process through life (wound healing) & tumor development

Arteriogenesis

Remodeling of existing collateral vascular pathways to make them larger and enhance flow.

Capillary Beds

Communication between blood vessels

Portal System

Two capillary beds in a series

Collateral Pathway

Network of interconnected blood vessels that provides an alternative route for blood flow, bypassing a blockage in a major artery or vein

Venous Anastomosis

Communicating venules provide alternating pathways for the return of blood to the heart from a capillary bed.

Arterial Anastomosis

Communications between arteries provide alternate paths to supply a capillary bed

Anastomoses

Provide collateral pathways for blood flow

Anatomic End Artery

No collateral pathways(central artery of retina)

Functional End Artery

Anastomoses are too small to provide an adequate collateral pathway (splenic artery)

Lymphatic System

Drainage of fluid and leaked plasma in the interstitial space of tissues, and the removal of cellular debris and infection.

Lymphatic Capillary Plexuses

Surrond capillaries

Lymphatic Vessels

Thin-walled, valved, and parallel the blood vessels and drain lymph.

Lymph Nodes

Masses of lymphatic tissue that filter lymph. Station in the middle of the lymph flow from the capillaries to the heart.

Lymphocytes

Immune cells that react to foreign materials

Lymphoid Tissue

Places that generate lymphocytes (red bone marrow, thymus, tonsils, MALT)

Flow of Lymph

1. Lymphatic capillary plexus

2. Afferent lymphatic vessels 

3. Lymph nodes

4. Efferent lymphatic vessel

5. Lymphatic ducts

6. Venous return

Lymphatic Ducts

Right lymphatic duct and thoracic duct

Right Lymphatic Duct

Empties at junction of the right internal jugular and right subclavian veins at venous angle (drains upper limb and head and neck)

Thoracic Duct

Empties into the junction of the left internal jugular and left subclavian veins (lower limbs and abdomen)

Right Lymphatic Duct

Lymph from right upper limb, right thorax, and right side of head 

Thoracic Duct

Lymph from left face and most of the body.

Lymphedema

Swelling due to the accumulation of lymph fluid (remove tits could remove ducts)

Cancer and Lymph

Closer infiltration of cancer is to the main route of return to venous circulation, the more advanced or dangerous condition

Stage III Breast Cancer

1. Cancer in 10 or more lymph nodes in the axilla

2. Cancer in lymph nodes above or below the collarbone

3. Cancer in lymph nodes in the axilla near the breastbone