Vascular Anatomy Flashcards
What is the broad definition of blood vessels?
They are the channels where blood is distributed throughout the body to the tissues
How many closed vessel systems are in the body?
Two
What are the two closed vessel systems in the body?
Pulmonary vessels
Systemic vessels
How are vessels classified? (3)
Arteries
Capillaries
Veins
What is the function of arteries?
To carry blood away from the heart
What do arteries typically contain?
Oxygenated blood
What is the total blood volume that is in the arteries?
Approx 10%
What are the three layers that arteries are composed of?
Tunica Intima (Inner) Tunica Media (Middle) Tunica Externa/Adventitia (Outer)
What is the arterial tunica intima made of?
Continuous smooth lining of endothelium cells
What is the arterial tunica media made of?
Smooth muscle
What is the vasa vasorum?
It provides the blood supply to the artery
Where is the vasa vasorum located?
It is located in the arterial tunica media
What is the arterial tunica externa made of?
Strong flexible tissue which helps hold the vessel open and prevents tearing during movement
What are the five important arteries we should know in the upper extremities?
Common carotid artery Brachiocephalic artery Brachial artery Radial artery Ulnar artery
What are the five important arteries in the lower extremities?
Abdominal aorta Common iliac artery Femoral artery Posterior tibial artery Anterior tibial artery
What is the name of the arterial system that feeds the brain?
Circle of Willis
What is special about the aorta? (2)
It is the largest artery
Its branches lead to all the organs of the body, supplying them with oxygen and nutrients
How many regions of the aorta are there?
Four
What are the four regions of the aorta?
Ascending aorta
Arch of the aorta
Thoracic aorta
Abdominal aorta
What is the function of veins?
They carry blood towards the heart
What do veins carry?
They typically carry deoxygenated blood
How much blood volume do veins hold?
Approx 70%
What are the three layers of veins?
Tunica Intima (Inner) Tunica Media (Middle) Tunica Externa/Adventitia (Outer)
What is the function of the vein’s tunica intima?
It has endothelium cells that produce semi-lunar valves
What is the function of the vein’s tunica media?
It has the smooth muscle layer, which is much thinner than the arteries
What is the function of the vein’s tunica externa?
Protection
What is the venous blood reservoir?
It allows for accommodation of large amounts of blood with no change in the blood pressure
When discussing the venous blood reservoir, what is capacitance?
It gives the vein’s the capacity to stretch
What are the five major veins in the hand and wrist?
Digital dorsal (Finger) Dorsal metacarpal (Between knuckles, going back towards wrist) Dorsal venous network (Remaining rest of back of hand and wrist) Cephalic vein (radial vein) Basilic vein (ulnar vein)
What are the six major veins of the arm?
Cephalic (thumb side, upper arm)
Median cubital (pinky finger, upper arm)
Accessory cephalic (ACF)
Basilic (Pinky side of ACF)
Distal portion of cephalic (thumb side of forearm)
Distal median antebrachial (pinky side of forearm)
What are capillaries?
They are the connection between the arteries and the veins
What are capillaries composed of?
Only endothelium tissue
What is the total blood volume of the capillaries?
Approx 5%
Who believed that the heart was a ‘sucking’ organ?
Galen
What are capillaries composed of?
Endothelium tissue
What is the vital role that capillaries play?
The exchange of gases, nutrients and waste between blood and the tissues
How thick are capillaries?
One cell thick
What are fenestrations in capillaries?
Small holes that allow fluid to move across the membrane
Blood flow into the capillaries is regulated by smooth muscle, what is this called?
Pre-capillary sphincters
If the blood flow in capillaries is constricted, it is directed through metarterioles. What is this process called?
Arteriovenous anastomoses or AV shunting
What is capillary microcirculation?
It is where 90% of fluid is returned to the system and 10% is collected by lymphatic vessels and returned to circulation in the venous system
What is blood flow? (2)
It is the movement of blood through the body
It moves from an area of high pressure to an area of low pressure
Where is the area of the highest pressure in blood flow?
The systolic contraction of the heart
Where is the area of the lowest pressure in blood flow?
It is found in the vena cava as it enters the right atrium.
The pressure in the right atrium is known as the central venous pressure
What is blood velocity?
It is the rate at which the blood flows
Where is the blood velocity the greatest?
In the aorta
Where is the blood velocity the slowest?
In the capillaries
What are the three things venous return is dependant on? (3)
Muscle action
Respiratory movements
Contraction of veins
What is the average blood volume?
70ml/kg
What is the average blood volume for an adult female?
4-5 Liters
What is the average blood volume for an adult male?
5-6 Liters
How much does the total blood volume account for in the total body weight?
Approx 8%
What are the three activities of blood?
Transportation
Regulation
Protection
What does the blood do when its transporting? (2)
It is carrying O2, CO2 and waste products to the lungs and kidneys
Carries hormones from endocrine system to target tissues
What is the blood doing when it is regulating? (3)
It maintains body temperature
Fluid and electrolyte balance (pertaining to osmotic pressure)
Functions with pH regulation with buffers
What is the blood doing when its protecting? (3)
It provides clotting mechanisms
Infection control (WBC)
Antibodies are found in the blood
What is the percentages and composition of blood? (2)
Plasma - 55%
Formed elements - 45%
What are the formed elements of the blood composed of? (3)
Leukocytes
Thrombocytes (Platelets)
Erythrocytes (largest portion)
What is the normal percentage of hematocrit in an adult male?
40-54%
What is the normal percentage of hematocrit in an adult female?
38-47%
What is anemia?
A decrease in red blood cells
What is polycythemia?
An increase in red blood cells
What is a common cause of polycythemia?
High altitudes
The formed elements in the blood are formed from a ________?
Hemocytoblast
What is the most abundant type of formed element?
Erythrocytes
What is the basic shape of erythrocytes?
Biconcave discs (Donut shaped)
How are new erythrocytes formed?
They are created from stem cells
Approximately how many hemoglobin molecules are found in an RBC?
200-300 million
What does a hemoglobin molecule consist of?
Four protein chains (globin) that are bound together by heme groups
What does each heme group contain?
Iron atom
How many iron atoms are in a heme group?
4
As a heme group contains four iron atoms, what does this allow to happen?
Allows the hemoglobin to attach to 4 O2 or 4 CO2 molecules
What is the function of oxyhemoglobin?
To transport oxygen to the tissues
What is the function of deoxygemoglobin?
It is when the oxygen is released at the tissues and is returning to the lungs for exit from the body
What is carbonic anhydrase?
An enzyme that catalyzes the interconversion of dissolved bicarbonates and carbon dioxide
What is the production of erythrocytes called?
Erythropoiesis
What happens in erythropoiesis?
The production of stem cells which through several stages of mitosis will reach mature blood cells and then reach the blood stream
What are the three main things essential to normal RBC production?
Iron
Vitamin B12
Folic Acid
If oxygen levels reaching the tissue decrease then it stimulates the release of ____________?
Erythropoietinogen
Where is renal erythropoietic factor produced at?
Kidneys
How long do normal erythrocytes live for?
Approx 120 days
What happens when an erythrocytes are defective or worn out?
Macrophages in the spleen and liver remove them
What happens to the hemoglobin in the erythrocytes when they are destroyed?
It is broken down and the heme is reused for production (broken down to iron and bilirubin) and sends the iron to the bone marrow and bilirubin is excreted into the bile of the liver
What size are leukocytes?
Larger than RBC’s but are fewer in number
What are agranulocytes?
Leukocytes formed in the lymphatic system
What are granulocytes?
They are leukocytes formed in the red bone marrow
Why do leukocytes appear white?
They are derived from hemocytoblast stem cells by they do not lose their nuclei or accumulate hemoglobin
What are five main functions of leukocytes?
Phagocytic Produce antibodies Secrete histamine Secrete heparin Neutralize histamine
What is leukocytosis?
It is an increase in the total number of WBC’s
What is leukopenia?
Decrease in the total number of WBC’s
What is leukemia?
Cancer of the lymph glands and bone marrow resulting in overproduction of white blood cells
What are the three types of granulocytes?
Neutrophils
Easinophils
Basophils
What is the function of neutrophils? (3)
They are the most common (60-70%), have multi-lobed nuclei
Can move from blood vessels to enter tissue spaces (diapedesis)
First to respond to to tissue damage where they engulf bacteria (phagocytosis)
What is the function of easinophils? (4)
2-5% with 2 lobed nucleus
Found in the respiratory and digestive tracts
Neutralize histamine and destroy parasitic worms
Increase in the number during allergic reaction
What is the function of basophils (4)
They are the least numerous (1%), U shaped nuclei
Capable of entering into the tissue space (diapedesis)
When they leave the blood and enter the tissue they are considered mast cells
They then secret histamine (dilates vessels) and heparin (anticoagulant)
What are the two types of agranulocytes?
Monocytes
Lymphocytes
What are the functions of lymphocytes? (5)
20-25%, spherical shaped nuclei
Abundant in lymphoid tissue
Important in defence
T cells attack bacteria and viruses
B cells produce antibodies
What is the function of monocytes? (4)
3-8%, U or bean shaped nuclei
When they leave the blood and enter the tissue they are called macrophages
Capable of engulfing bacteria and virus infected cells
Finish the clean-up of cellular debris initially started by the neutrophils
What is another name for thrombocytes?
Platelets
What is the definition of a thrombocyte?
They are not a complete cell, actually parts of megakaryocytes from the red bone marrow
What is the function of thrombocytes? (4)
Agglutination
Adhesiveness
Aggregation
They become sticky and clump together to form platelet plugs
What is thrombocytopenia?
A decrease in the number of platelets in the blood, resulting in the potential for increased bleeding and decreased ability for clotting
What can thrombocytopenia be a side effect of? (3)
Chemotherapy
Certain drugs may cause the decrease
Idiopathic thrombocytopenic purpura
What is thrombocytosis?
An increase in the number of platelets in the blood
What can thrombocytosis be a result of? (5)
Splenectomy Following acute hemorrhage Rheumatoid arthritis Infections Certain malignancies
What are the three major classess of plasma proteins?
Albumins
Globulins
Fibrinogens
What is the function of plasma proteins? (2)
They are the most abundant of solutes
They remain in the blood or interstitial fluid and are not used for energy
What are two key points with albumin?
Account for 60% of proteins
Attribute to osmotic pressure
What are three key points of globulins?
They account of 36%
They produce alpha and beta (produced in the liver and transport lipids and vitamins)
They produce gamma (produced in lymphoid tissue and are antibodies)
What are four key points of fibrinogen?
They account for 4%
They are the largest of the molecules
They are produced in the liver
They function in clotting
What is the definition of hemostasis?
The stoppage of bleeding
What does hemostasis occur with? (3)
Vasoconstriction
Platelet plug formation
Coagulation
How does vasoconstriction aid in hemostasis?
It restricts the flow of blood through vessels by constricting (spasms)
How does platelet plug formation aid in hemostasis? (3)
Platelets attracted to the collagen in the connective tissue
As they accumulate, they release serotonin (stimulates smooth muscles to contract)
This prolongs vasoconstriction
How does coagulation aid in hemostasis? (5)
Blood contains procoagulants and anticoagulants
Anticoagulants predominate typically to maintain blood as a fluid
In an injury, procoagulants increase in activity
Chemical reactions and the use of clotting factors aid in the plug formation
Ca and Vit K are important in the process
What is the process of hemostasis? (5)
The damaged tissue release chemicals
This triggers a cascade of reactions involving coagulation factors that result in the formation of prothrombin activator (PA)
With Ca and PA, prothrombin in the plasma is converted to active thrombin (which is normally inactive)
Thrombin with Ca acts as an enzyme to convert inactive soluble fibrinogen into an active non-soluble fibrin
This begins to form fibers to trap blood cells
What is an embolus?
The formation of a clot from platelets or leukocytes
What is a thrombus?
An aggregation of blood factors, primarily platelets and fibrin with entrapment of cellular elements
What is a blood type based on?
Specific proteins (antigens) and antibodies related to RBC’s
Where are agglutinogens for blood type found?
The antigens (agglutinogens) are found on the cell membrane of the RBC
Where are the agglutinins for blood typing found?
The antibodies (agglutinins) are found in the plasma
There are many groups when dealing with blood typing, but what are the two most important?
ABO
Rh
Who and when was the ABO system discovered?
Discovered by Dr. Karl Landsteiner in 1901
What are the four blood types?
A
B
AB
O
What is the ABO group based on? (4)
Certain aggultinogens (A&B antigens)
Type A has A
Type B has B
Type O has none
How is the ABO group determined?
It is inherited
What type is known as the universal recipient?
Type AB
What type is known as the universal donor?
Type O
What is Rh factor +?
Rh agglutinogens are on the surface of the RBC (85% of population)
What is Rh factor -?
Rh agglutinogens are not present
