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Blood vessels contribute to homeostasis by
- providing the structures for the flow of blood to and from the heart
- the exchange of nutrients and wastes in tissues.
- play an important role in adjusting the velocity and volume of blood flow.
Cardiovascular system contributes to homeostasis of other body systems by
- transporting and distributing blood throughout the body to deliver materials (such as oxygen, nutrients, and hormones)
- carry away wastes.
The five main types of blood vessels
What are Arteries and what do they do
- carry blood away from the heart to other organs.
- Large, elastic arteries leave the heart divide into medium-sized, muscular arteries that branch out into the various regions of the body.
- Medium-sized arteries then divide into small arteries, which in turn divide into still smaller arteries called arterioles (ar-TĒR-ē-ōls)
|What are arterioles and what do they do
- medium sized arteries divide into smaller arteries called arterioles
- Arterioles enter a tissue, they branch into numerous tiny vessels called capillaries
Capillaries what are they
- allow the exchange of substances between the blood and body tissues.
- Groups of capillaries within a tissue reunite to form small veins called venules (VEN-ūls).
What are Venules and Veins
- Caillaries group and reunite to form small veins called venules
- these in turn merge to form progressively larger blood vessels called veins.
- Veins (VĀNZ) are the blood vessels that convey blood from the tissues back to the heart.
- refers to the growth of new blood vessels.
- It is an important process in embryonic and fetal development,
- serves important functions such as wound healing, formation of a new uterine lining after menstruation, formation of the corpus luteum after ovulation, and development of blood vessels around obstructed arteries in the coronary circulation.
- Several proteins (peptides) are known to promote and inhibit angiogenesis.
Which vessel—the femoral artery or the femoral
vein—has a thicker wall? Which has a wider lumen?
- The femoral artery has the thicker wall; the femoral vein has the wider
The wall of a blood vessel consists of three layers, or tunics, of different
- an epithelial inner lining,
- a middle layer consisting of a smooth muscle and
- elastic connective tissue,
- a connective tissue outer covering.
three structural layers of a blood vessel
both vein & artery
- the tunica interna (intima) - innermost
- tunica media
- tunica externa - outermost
Arteries n Veins carry blood ....
- Arteries carry blood from the heart to tissues
- veins carry blood from tissues
- to the heart.
The tunica interna
- forms the inner lining of a blood vessel and is in direct contact with the blood
- as it flows through the lumen, or interior opening, of the vessel
The tunica media (media =middle) is
- a muscular and connective tissue layer that displays the greatest variation among the different vessel types
- In most vessels, it is a relatively thick layer
- comprised mainly of smooth muscle cells and substantial amounts of elastic fibers.
- The primary role of the smooth muscle cells, which extend circularly around the lumen like a ring encircles your finger, is to regulate the diameter of the lumen
- In addition to regulating blood flow and blood pressure, smooth muscle contracts when vessels are damaged to help limit loss of blood through the injured vessel,
- smooth muscle cells help produce the elastic fibers within the tunica media that allow the vessels to stretch and recoil under the applied pressure of the
the tunica externa
- outer covering of a blood vessel,
- consists of elastic and collagen fibers
- Separating the tunica externa from the tunica media
- is a network of elastic fibers, the external
- elastic lamina which is part of the tunica media. The tunica externa contains numerous nerves and, especially in larger vessels, tiny blood vessels
- that supply the tissue of the vessel wall.
- These small vessels that supply blood
- to the tissues of the vessel are called vasa vasorum (vas = vessel), or vessels to the vessels.
Elastic arteries are the largest or smallest arteries?
- are the largest arteries in the body,
- ranging from the garden hose–sized aorta
- and pulmonary trunk to the finger-sized branches of the aorta.
What is Elastic Lamellae
- Elastic Arteries...These vessels are characterized by well-defined internal and external elastic
- laminae, along with a thick tunica media that is dominated by elastic fibers,
- called the elastic lamellae
What are the 2 major trunks that exit the heart?
- Elastic arteries include the two major trunks that exit the heart (the aorta and
- the pulmonary trunk),
- along with the aorta's major initial branches,
- such as the brachiocephalic, subclavian, common carotid, and common iliac arteries
aorta's major initial branches
- common carotid
- common iliac arteries
All veins of the symatic circulation drain into the
- Superior Vena Cava,
- Inferior vena cava
- or coronary sinus
three different types of capillaries
- continuous capillaries,
- fenestrated capillaries,
- and sinusoids
How do materials move through capillary walls
- Materials cross capillary walls through intercellular clefts and fenestrations,
- via transcytosis in pinocytic vesicles, and through the plasma membranes of
- endothelial cells
venules that initially receive blood from capillaries are called
Valves in veins allow blood to flow in one direction only...
towards the heart
Why are valves more important in arm veins and
leg veins than in neck veins
- because, when you are standing, gravity causes pooling of blood in the veins of
- the free limbs but aids the flow of blood in neck veins back toward the heart.