What three layers compose blood vessels?
1. TUNICA ("coat") INTIMA
2. TUNICA MEDIA
3. TUNICA ADVENTITIA (TUNICA EXTERNA)
Which layer of blood vessels contains smooth muscle tissue?
TUNICA MEDIA has smooth muscle and elastic fibers
Which layer has elastic fibers?
SMOOTH MUSCLE Allows blood to be directed to parts of body by vasoconstriction.
What are the functions of smooth muscle and elastic fibers?
ELASTIC FIBERS: within smooth muscles. Allows blood vessels to return to normal size, and to stretch during systole.
What are the three functions of the TUNICA ADVENTITIA (TUNICA EXTERNA)
TUNICA ADVENTITIA (TUNICA EXTERNA):
a. Protects the blood vessel (strong)
b. Gives vessel strength for shape
c. Anchors vessel to surrounding tissue; loosens with age.
Which vessels carry blood away from the heart?
Which vessels have a smaller lumen, veins or arteries?
Which have thicker walls?
Which have more elastin?
Which have valves?
• Veins have valves, arteries do not. Lymph vessels also have valves
Do arteries always contain oxygenated blood?
• No; the pulmonary and umbilical arteries have deoxygenated (blue) blood.
What is the largest type of blood vessel?
What do they contain a lot of?
• There of lots of elastic fibers in the tunica media
What type of artery is distal to elastic arteries, and consists of most of the
What layer in these arteries is thick?
• Muscular Arteries
• Tunica media is thick
What are three causes of an aneurysm?
- Defect in part of the artery wall
- High blood pressure
- Congenital (present at birth)
How to Recognize a Stroke ("STROKE")
S * Ask the individual to SMILE.
T * Ask the person to TALK and SPEAK A SIMPLE SENTENCE (Coherently; i.e. It is sunny out today)
R * Ask him or her to RAISE BOTH ARMS.
O * Open the mouth and stick out the tongue
K * Keep them comfortable and still
E * Get EMERGENCY help (911)
If one side of the body responds differently than the other side, or if they have trouble with the task, call 911.
Which artery is a good place to take a pulse?
Femoral artery: good place to take a pulse since it is superficial, but that also makes it susceptible to injury.
The circle of Willis forms a loop around which structures?
Circle of Willis forms a loop around the pituitary gland and the optic chiasma
Which are the smallest blood vessels, and are found everywhere?
Which layer do they have?
Where is the only site of nutrient, gas exchange, and waste exchange in the ardiovascular system?
They only have an endothelium.
The diameter of a typical capillary is similar to that of what?
What are the three types of capillaries?
Which are the most common?
Which have pores?
Which have very large gaps?
Capillary diameter is similar to an erythrocyte
- Continuous - most common
- Fenestrated ("window") - have pores
- Discontinuous (Sinusoids) - have very large gaps
Which capillaries are found where lots of fluids need to be moved back and forth, such as in the small intestine?
What type of capillaries are found in the red marrow because their gaps are so large, a RBC can fit through?
DISCONTINUOUS (sinusoidal) capillaries
What is found at the start of each capillary?
What is the function of this structure?
PRE-CAPILLARY SPHINCTER controls the flow of blood to individual capillaries. It directs the blood flow to specific cells.
If one cell is starving, the capillary next to it will open.
The sphincter opens and closes depending on the needs of individual cells.
Blood always flows to those cells and tissues that need it. There is not enough blood to go around.
Name the 2 varieties of VEINS
VENULE: this is the smallest. It takes blood from the capillary to the vein.
VEIN: takes blood to the heart.
How is blood able to get uphill and return to the heart without backing up?
Skeletal muscle pushes on the vein to move the blood uphill, and the valves keep it from falling backwards and backing up
What are the only BLOOD vessels that have valves
• Veins are the only BLOOD vessels that have valves (although LYMPH vessels also have valves).
What vessel is often used to bypass a damaged coronary artery in coronary bypass surgery, and is the most likely vein to become varicose?
Name 3 Veins that are rich in oxygen and nutrients:
Hepatic Portal vein
What are the two types of EDEMA?
Which is more severe?
1. Pitting: worse in the evening
2. Non-pitting This is more severe because it does not go away easily. Just as swollen in morning as evening
What causes VENOUS STASIS ULCERS?
Who gets them most often?
What are three issues that must be treated when one gets a venous stasis ulcer?
• Varicose veins with excess acid products from the blood plasma (sugar, carbon dioxide, etc), which eventually erode all the way to the skin.
• Common in diabetics.
• Treatment must address sugar levels, vein problem, and the open wound.
Why is PHLEBITIS dangerous?
Phlebitis can be associated with the formation of blood clots (thrombosis), usually in the deep veins of the legs, the condition is called Deep Vein Thrombophlebitis (DVT).
What are the signs and Symptoms of DVT?
Redness (erythema) and warmth with a temperature elevation of a degree or more above the baseline
Pain or burning along the length of the vein
Vein being hard, and cordlike
Need to go to the emergency room if all symptoms are present
What are SPIDER VEINS?
Are they dangerous?
What are two treatments?
Small superficial veins become varicose and do not function properly.
Cause an unsightly appearance but are not dangerous.
Injections of alcohol or saline into the vein will sclerose them (scar them shut), or they can be lasered.