Blood vessels(ch 23) Flashcards
1
Q
Blood vessels
A
- are an efficient mode of transport for oxygen, carbon dioxide, nutrients, hormones, and waste products to and from body tissues.
- The heart is the mechanical pump that propels the blood through the vessels.
- the heart and blood vessels form a closed-loop system
- Blood vessels are not rigid and immobile
- they can pulsate and change shape in accordance with the body’s needs
2
Q
Blood vessels
A
- Blood vessels often share names with either the body region they traverse or the bone next to them.
- For example, the radial artery travels near the radius, and the axillary artery is in the axillary region.
- Some blood vessels are named for the structure they supply.
- For example, the renal arteries supply the kidneys, the gonadal arteries supply the gonads, and the facial arteries supply the face.
Arteries and veins that travel together (called companion vessels) sometimes share the same name.
- For example, the femoral artery is accompanied by the femoral vein.
- Writing out your own simplified flowchart of blood vessels for each body region will help you better understand and remember the pattern of blood flow in that region.
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3
Q
Anatomy ofBlood vessels
A
- _ Systemic Circulation:_ consists of the blood vessels that extend to all body regions.
- pulmonary circulation: consists of the vessels that take the blood to and from the lungs for the purpose of gas exchange
- Both circulations work continuously and in tandem with each other.
4
Q
Anatomy of Blood vessels
A
- 3 classes of blood vessels
- arteries,
- capillaries,
- veins
5
Q
arteries, capillaries, & veins
A
- _Arteries: _ arteries carry blood away from the heart to the body
- Arteries branch into smaller and smaller vessels until they feed into the capillaries
- _Veins: _return blood to the heart, from the capillaries
- veins become progressively larger as they merge and come closer to the heart
6
Q
anastomosis
A
- The site where two or more arteries (or two or more veins) converge to supply the same body region
- Veins tend to form many more anastomoses than do arteries
7
Q
Blood Vessel Tunics
A
- Both artery and vein walls have three layers, called Tunics
_ These tunics are the:_
tunica intima
**tunica media **
tunica externa
- The tunics surround the Lumen or inside space, of the vessel through which blood flows
8
Q
tunica externa (adventitia)
A
- The outermost layer of the blood vessel wall
- composed of Areolar Connective Tissue that contains Elastic and Collagen Fibers
- tunica externa helps anchor the vessel to other structures OR tissues
- large blood vessels require their own blood supply; smaller arteries that supply the larger arteries are called vasa vasorum
- vasa vasorum runs through the tunica externa.
9
Q
TUNICA MEDIA
A
- ** middle layer** of the vessel wall
- composed of circularly arranged layers of smooth muscle cells
- Sympathetic input causes the smooth muscle to contract, resulting in vasoconstriction (narrowing of the blood vessel lumen)
- parasympathetic input results in, **vasodilation **(widening of the blood vessel lumen)
10
Q
tunica intima( interna):
A
- innermost layer of a blood vessel wall
- composed of an endothelium and a subendothelial layer
11
Q
Types of Arteries
A
- Arteries transport blood away from the heart.
- The arteries in the systemic circulation carry oxygenated blood to the body tissues. the pulmonary arteries carry deoxygenated blood to the lungs
- as an artery’s diameter decreases there is a corresponding decrease in the amount of elastic fibers and a relative increase in the amount of smooth muscle
- three basic types of arteries are : - elastic arteries, muscular arteries** ** arterioles
12
Q
Elastic Arteries
A
- **Elastic arteries **are the largest arteries
- diameters ranging from 2.5 to 1 centimeter
- They are also called conducting arteries because they conduct blood away from the heart to the smaller muscular arteries
- Examples of elastic arteries include the aorta and the pulmonary, brachiocephalic, common carotid, subclavian, and common iliac arteries.
- Elastic arteries branch into muscular arteries.
13
Q
Muscular Arteries:
A
- diameters ranging from 1 centimeter to 3 millimete
- _ two circumscribed rings_ - internal elastic lamina: separates the tunica intima from the tunica media -external elastic lamina: separates the tunica media from the tunica externa
- Muscular arteries have a proportionately thicker tunica media
- called distributing arteries because they distribute blood to body organs and tissues
- Most of the named blood vessels (such as the brachial, anterior tibial, coronary, and inferior mesenteric arteries) are examples of muscular arteries.
- Muscular arteries branch into arterioles.
14
Q
Arterioles:
A
- are the smallest arteries
- diameters ranging from 3 millimeters to 10 micrometers
- arterioles have less than six layers of smooth muscle in their tunica media
- Larger arterioles have all three tunics, whereas the smallest arterioles may have an endothelium surrounded by a single layer of smooth muscle fibers
- vasoconstriction increase blood pressure(sympathetic)
- vasodilation decreases blood pressure(parasympathetic)
15
Q
CAPILLARIES
A
- smallest blood vessels, connect arterioles to venules
- consist only of a tunica intima
- composed of a very thin, single layer of endothelium and a basement membrane;
- there is no subendothelial layer.
- allowa gas and nutrients exchange between blood in the capillaries and body tissues to occur rapidly
- capillaries are called the _functional units _of the cardiovascular system
- a group of capillaries (10–100) functions together and forms a capillary bed
