Midterm | Blood Vessels Flashcards
Channels that carry blood throughout the body.
BLOOD VESSELS
Blood vessels are (1) shape but never in a (2) that starts and ends at the (3).
- tube-like
- straight line
- heart
Types of blood vessels:
- Arteries
- Arterioles
- Capillaries
- Venules
- Veins
Layers of blood vessel wall
- Tunica interna (intima)
- Tunica media
- Tunica externa (adventitia)
Epithelial inner lining of BV
TUNICA INTERNA (INTIMA)
Structure of BV that has direct contact with blood
TUNICA INTERNA (INTIMA)
Layers of the Tunica Interna (Intima)
- Endothelium
- Basement membrane
- Internal elastic lamina
Facilitates efficient blood flow by reducing friction
Endothelium
Provides a physical support base for the endothelial layer; provides resilience for stretching and recoil
Basement membrane
Facilitates diffusion of materials; looks like swiss cheese
Internal elastic lamina
TUNICA MEDIA is a (1) and (2)
- smooth muscle
- elastic connective tissue layer
Layers of Tunica Media
- Smooth muscle cells
- External elastic lamina
Regulates diameter of lumen by contracting (vaso constriction) and relaxing (vaso dilation)
Smooth muscle cells
Has the same function of internal elastic lamina: facilitates diffusion of materials; passageway of nutrients
External elastic lamina
Outer covering of blood vessels
TUNICA EXTERNA (ADVENTITIA)
TUNICA EXTERNA (ADVENTITIA) consists of
- Elastic and collagen fibers
- Numerous nerves
- Vasa vasorum
Small vessels that supply blood to the tissues of
the vessel
Vasa vasorum
Vasa vasorum means (1) and are easily seen on (2) such as (3)
- Vessels to the vessels
- Large vessels
- aorta
Functions of the Tunica Externa (Adventitia)
- Supply the vessel wall with nerves
- Supply the vessel wall with blood
- Helps anchor the vessels to surrounding tissues
Carries blood away from the heart
ARTERIES
Have high compliance
ARTERIES
What does “arteries have high compliance” mean?
Their walls easily stretch or expand without tearing in response to a small
increase in pressure
ARTERIES Types (+ other terms)
❑ Elastic arteries/ Conducting arteries
❑ Muscular arteries/ Distributing arteries
Largest arteries and examples
Elastic arteries
ex. Aorta, pulmonary trunk
Elastic arteries contains —
elastic fibers
They help propel blood onward while the ventricles are relaxing
Elastic arteries
Greater vasoconstriction and vasodilation
Muscular arteries
What do muscular arteries contain, and give example of muscular arteries?
Smooth muscle
ex. Brachial arteries
Continue to branch and ultimately distribute blood to each of the various organs
Muscular (Distributing) arteries
Union of two or more blood vessels supplying the same body region.
ANASTOMOSIS
Alternative route of blood flow through an anastomosis
Collateral circulation
Arteries that do not anastomose
End arteries
Possible cause/s of anastomosis
Inborn or surgical anastomosis
Small arteries (microscopic)
ARTERIOLES
Regulate blood flow into the capillary
ARTERIOLES
Other term for ARTERIOLES
Resistance vessels
Terminal end of arteriole
Metarteriole
Metarteriole-capillary junction forms — that monitors blood flow into capillary
precapillary sphincter
Smallest of blood vessels
CAPILLARIES/ EXCHANGE VESSELS
Composed only of single layer of endothelial cells and basement membrane
CAPILLARIES/ EXCHANGE VESSELS
What do capillaries lack?
Tunica media and tunica externa
Venule that receives blood from a capillary
postcapillary venule
The flow of blood from a metarteriole through capillaries and into a postcapillary venule
Microcirculation
Capillaries are found near almost every cell in the body, but their number varies with the — of the tissue they serve
metabolic activity
Body tissues with high metabolic requirements
Muscles
Brain
Liver
Kidney
Tissues with lower metabolic requirements
Tendons
Ligaments
Tissues where capillaries are absent
Cornea and lens of the eye
Cartilage
Different types of capillaries, and the gaps found in them
- Continuous capillaries: Intercellular cleft
- Fenestrated capillaries: Fenestrations
- Sinusoid: Intecellular gap
Where continuous capillaries are found
CNS
Lungs
Muscle tissue
Skin
Where fenestrated capillaries are found
Kidney
Villi of SI
Choroid plexus of brain
Ciliary processes of eyes
Most endocrine glands
Where sinusoids are found
Bone marrow
Liver
Thin walls; do not maintain shape
VENULES
Function of venules
Return flow of blood back toward the heart from the capillary
Function as significant sites of exchange of nutrients and wastes and white blood cell emigration.
Postcapillary venules
Veins have very (1) walls and also contain (2)
- thin
- valves
What can be noted regarding veins when compared to arteries?
Larger lumen and are more numerous
Crosses the accompanying artery to form ladderlike rungs between the paired veins
Anastomotic vein
Superficial veins appear — under the skin
blue
Microscopic (15–300 μm in
diameter)
Arterioles
Microscopic; 5–10 μm
in diameter
Capillaries
Microscopic (10–50 μm in diameter)
Postcapillary venules
Microscopic (50–200 μm in diameter)
Muscular venules
Range from 0.5 mm to 3 cm in diameter
Veins
Well-defined internal elastic lamina.
Elastic and Muscular arteries
Thick TM and dominated by elastic fibers; well-defined external elastic lamina.
Elastic arteries
Thick TM and dominated by smooth muscle; thin external elastic lamina.
Muscular arteries
TE thinner than TM
Elastic arteries
TE thicker than TM
Muscular arteries
Conduct blood from heart to muscular arteries
Elastic arteries
Distribute blood to arterioles
Muscular arteries
Deliver blood to capillaries and help regulate blood flow from arteries to capillaries
Arterioles
Permit exchange of nutrients and wastes between blood and interstitial fluid
Capillaries
Distribute blood to postcapillary venules
Capillaries
Pass blood into muscular venules
Postcapillary venules
Permit exchange of nutrients and wastes between blood and interstitial fluid and function in white blood cell emigration
Postcapillary venules
Pass blood into vein; act as reservoirs for accumulating large volumes of blood (along with postcapillary venules)
Muscular venules
Return blood to heart, facilitated by valves in limb veins
Veins