Human vasculature Flashcards
Circulatory system
Organ system that transports blood around every part of the body.
This allows the transportation of nutrients and oxygen to tissues and the removal of metabolic waste from tissue,
Composed of:
Systemic- Under high pressure and high oxygen levels. High pressure from the aorta and other arteries.
Pulmonary- Contains low oxygen and pressure. Blood passes the lungs and pulmonary artery
Portal system
Organ system that composed of venous blood with high digestion products.
Contains veins from:
Spleen, stomach, intestines and liver.
Veins from the spleen, stomach and intestine drain into the liver via the hepatic portal vein.
Blood leaves the liver via the hepatic vein, and enters the inferior vena cava.
Artery
Blood vessel under high pressure that transports blood away from the heart.
Two types of arteries:
Muscular
Elastic
Generally contains thick tunica media that helps to resist pressure.
Endothelium of blood vessels
Part of the tunica intima and is composed of squamous cells.
These endothelial cells are bound by junctional complexes
Endothelial cells also secrete clotting factors which maintains smooth muscle tone.
Thrombus
Blot clot that builds up through haemostasis.
This occurs when blood clots too easily and can block blood supply to tissues and cause hypoxia leading to infarctions.
Emboli
Moving blood clot.
Occurs when a blood clot detaches from its original position and transfers to a different site.
Atherosclerosis.
Narrowing of the blood vessel caused by lesions in the endothelium which build up plaque.
Plaque deposits can be calcium or fat based.
Muscular arteries
Arteries that distributes blood to different tissues.
The tunica media is composed mainly of smooth muscle which allows vasoconstriction.
This helps control blood flow to certain tissues/ organs.
These arteries are also pulsatile which helps to propel the blood.
Examples:
Axillary, brachial, radial.
Elastic arteries.
Arteries that pushes blood to the muscular arteries, downstream.
Their tunica media is mainly composed of elastic tissue which looks wavy under microscopes.
These arteries are close to the heart so help to resist surges in blood due to high pressure from the ventricles.
Examples:
Aorta, common carotid, pulmonary artery, brachiocephalic artery, subclavian artery.
Arterioles
Branches from the muscular arteries and distributes blood to the capillaries.
Composed of smooth muscle in the the tunica media which constricts to regulate blood flow.
This affects blood pressure in the capillary bed.
Capillaries
Blood vessels that directly provide blood to tissues and allow gaseous exchange.
Transfers oxygen, CO2, nutrients, hormones, cells and proteins into cells.
Two types:
Continuous
Fenestrated
Continuous capillaries.
Capillaries that have an uninterrupted lining composed just connecting enothelial cells.
Found in most structures including:
Skin, lungs and skeletal muscles.
Fenestrated capillaries
Capillaries with pores in the endothelial cells.
This is present in tissues where large molecules are exchange and molecular exchange is extensive:
Renal glomeruli
Endocrine glands
Intestine
End arteries
Arteries that do not anastomose.
Therefore if a portion of tissue has an end artery, this is the only blood supply it has.
Examples:
Splenic artery
Renal artery
Central retinal artery.
Occlusion of an end artery restricts blood flow to the tissue and can cause ischaemia and infarction.
Examples of occlusions of end arteries in medicine.
Myocardial infarction:
Occlusion of the coronary arteries.
Blindness:
Can be caused by occlusion from the central retinal artery.
