veins

• veins function is to collect oxygen-poor blood throughout your body and carry it back to your heart.
• veins carry oxygen-rich blood from your lungs to your heart.
• Veins are organized into a complex network called the VENOUS SYSTEM.
• Deep veins can be found in your muscles and along your bones.
• •        Your deep veins do the important work of moving your oxygen-poor blood back to your heart.
• In your legs, your deep veins hold about 90% of the blood that travels back to your heart.
• Your superficial veins are generally smaller than your deep veins.
• your superficial veins can be found just underneath your skin. So, you can easily see them.
• The largest vein in your body is a superficial vein called THE GREAT SAPHENOUS VEIN. It runs all the way from your ankle to your thigh in each leg
• Perforating veins are sometimes called CONNECTING VEINS or PERFORATOR VEINS.
• Perforating veins are short veins that carry blood from your superficial veins to your deep veins.
• •        This “second heart,” also called your PERIPHERAL HEART, springs into action each time you take a step.
• Superficial thrombophlebitis.

  This is when a clot forms just under your skin. Usually, the clot doesn’t travel to your lungs.
• Deep vein thrombosis (DVT).

  This serious condition happens when blood clots (called THROMBI) form in your deep veins.
• The clot can break free from your vein and travel to your lungs, causing a life-threatening PULMONARY EMBOLISM.
• Varicose veins

   These swollen, bulging veins are sometimes harmless but can lead to serious problems like blood clots
• Chronic venous insufficiency.

  When the one-way valves in your legs are damaged, they can’t effectively pump blood to your heart. DVT often causes this condition.
• Capillaries are delicate blood vessels that exist throughout your body
• •        Capillaries are the smallest blood vessels in your vascular system.
• they support the bone marrow by enabling new blood cells to enter your bloodstream.
• Brain

   by forming the blood-brain barrier. This structure delivers nutrients to the brain while preventing toxins from passing through.
• Endocrine system

  by delivering hormones to specific organs.
• Kidneys

  where peritubular capillaries filter blood, produce urine and absorb water and sodium.
• Liver

  by removing defective red blood cells and bacteria.
• Lungs

  by releasing carbon dioxide and taking in oxygen.
• Lymphatic system

   by collecting fluid from tissues and directing it to lymph nodes.
• Small intestine

  by transporting digested nutrients so they can nourish your cells.
• Endothelial cells

   are inside the capillary. They control the flow of fluid, nutrients and gases.
• Epithelial cells 

  form a protective layer around the endothelial cells.
• Continuous fenestrated capillaries 

  have small openings (fenestrae) that enable the rapid exchange of substances. This type of capillary is in your kidneys, small intestine and endocrine glands.
• Continuous non fenestrated capillaries

   have a lining through which only small molecules can pass. This type of capillary exists in the nervous system as well as fat and muscle tissue.
• Sinusoidal capillaries 

  have small fenestrae that allow certain substances to pass through. This type of capillary is in your liver and spleen.
• Arteriovenous malformation (AVM): 

  A tangle of arteries and veins in the brain or spinal cord that may bypass the capillaries. AV malformations aren’t just limited to your brain and spinal cord. They can occur in the limbs, trunk and organs.
• Capillary angiosarcoma:

  Cancer of the endothelial cells that can affect the capillaries.
• Capillary leak syndrome:

  A condition that causes a sudden drop in blood pressure. It sometimes requires emergency treatment.
• Hereditary hemorrhagic telangiectasia:

  An inherited blood vessel disorder that causes abnormal growths (telangiectases), which can burst.
• Hereditary hemorrhagic telangiectasia It’s also called OSLER-WEBER-RENDU SYNDROME.
• Macular degeneration:

  Damage to the inner eye due to capillary leaks.
• Microcephaly-capillary malformation syndrome: 

  A condition causing wide capillaries in individuals with abnormally small heads.
• Spider nevus:

   Small blood vessels that branch from a central spot, usually on your face, neck or chest. It’s also called SPIDER ANGIOMA or SPIDER TELANGIECTASIA.