Blood vessels Flashcards

1
Q

What are the 5 main types of blood vessels?

A
  1. Arteries
  2. Arterioles
  3. Capillaries
  4. Venules
  5. Veins
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2
Q

Main purpose of blood vessels?

A

Carry oxygen-rich blood away from the heart, transport it to the tissues of the body, and then return oxygen-depleted blood to the heart

It’s a closed system

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3
Q

What is angiogenesis?

A

Growth of new blood vessels

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4
Q

What is the role of arteries?

A

Carry blood away from the heart to the tissues

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5
Q

Role of arterioles?

A

Small arteries that connect to capillaries

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6
Q

What are capillaries?

A

Site of substance exchange between blood and tissue (thin walls allow this)

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7
Q

Role of venules?

A

Connect capillaries to veins

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8
Q

Role of veins?

A

Take blood back to the heart

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9
Q

A blood vessel wall consists of 3 major layers (tunics) of different tissue types. What are they?

A
  1. Tunica interna (which contains the endothelium, basement membrane and internal elastic lamina)
  2. Tunica media (smooth muscle and elastic fibres)
  3. Tunica external (elastic and collagen fibres)
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10
Q

Two main functional properties of blood vessels?

A
  1. elastic - allows them to accept blood under great pressure
  2. contractible - can increase/decrease lumen size to limit bleeding
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11
Q

Blood vessels are all sympathetically innervated. An increase or decrease in stimulation causes the diameter of vessels to increase or decrease?

A

Increase in stimulation - causes contraction

Decrease in stimulation - causes vasodilation

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12
Q

The tunica media of arteries have a thick muscular to elastic layer. They have high compliance (stretch easily without tearing). Name the two main types of arteries and their broad features/function.

A
  1. Elastic arteries - largest arteries, more elastic fibres, able to receive blood under pressure and propel forward. They are conducting arteries and a pressure reservoir.
  2. Muscular arteries - medium-sized, tunica media has more muscle than elastic and walls are relatively thick. They are distributing arteries, capable of vasoconstriction and vasodilation to adjust rate of flow
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13
Q

What are anastomoses

A

Union of two or more blood vessels supplying the same region of the body. They are a safety net against blockages.

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14
Q

Name some general features and functions of arterioles.

A
  • much smaller than arteries
  • regulate blood flow into capillaries
  • tunica media is thin with few layers of muscle
  • tunica internal is thin
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15
Q

Capillaries are the smallest blood vessel. Name some characteristics and functions.

A
  • thin-walled to allow the exchange of substances
    (e.g. no tunica media or tunica external, tunica internal is a single layer of endothelial cells and a basement membrane)
  • extensive in highly active tissue (e.g. muscles, liver, kidney and brain)
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16
Q

The 3 main types of capillaries are:
1. continuous
2. fenestrated
3. sinusoids

What are the main differences?

A

Continuous: endothelial cells form a continuous tube with gaps only between cells. Most common.

Fenestrated: plasma membranes have fenestrations or small pores.

Sinusoids: unusually large fenestrations with incomplete or absent basement membrane

17
Q

Venules are the smallest of the return veins collecting blood from the capillaries to return back to the heart.

There are two types: post-capillary venules and muscular venules.

Describe the main features of both these types and the main function of venules in general.

A

Venules drain capillary blood and begin the return of blood back to the heart; they serve as reservoirs for accumulating large volumes of blood.

Post-capillary venules are the smallest veins collecting blood from capillaries. They have a very porous endothelium.

Muscular capillaries have thicker walls (exchange w interstitial fluid can no longer occur).

18
Q

Do venules and veins have thicker or thinner walls than arteries?

A

Thinner

19
Q

Veins are larger than venules and have three distinct layers. Their function is to return blood to the heart.

What is a major structural difference between veins and arteries?

A

Veins have valves to prevent the backflow of blood

(Tunica internal and media are also much thinner than arteries, but the tunica external is thicker)

(also much more flexible and collapsible)

20
Q

Can veins withstand high pressure?

A

No - designed to hold volume at low pressure

21
Q

What are the major factors in moving venous blood back to the heart?

A
  1. contraction of skeletal muscle in lower limbs
  2. pumping action of the heart
22
Q

Where is the majority of blood in the cardiovascular system at rest?

A

Systemic veins and venules (blood reservoirs)

23
Q

Capillary exchange is the continuous movement of substances between the blood in systemic capillaries and interstitial fluid. What are the 3 basic mechanisms of exchange?

A
  1. diffusion
  2. transcytosis
  3. bulk flow
24
Q

Vessels which DISTRIBUTE blood to organs are called…?

A

Muscular arteries

25
Q

The opposition to blood flow in the walls of blood vessels creates..?

A

Resistance

26
Q

Blood tissues with high metabolic demands have extensive networks of…?

A

Capillaries

27
Q

Capillaries with very large intracellular clefts (or fenestrations) that allow to passage of proteins and cells are called what?

A

Sinusoids

28
Q

Groups of capillaries within a tissue reunite to form…?

A

Venules

29
Q

Pressure-driven movement of fluid from interstitial fluid into capillaries is known as what?

A

Reabsorption

30
Q

The tunica media contain connective tissue along with what?

A

Smooth muscle

31
Q

The small gaps present in plasma membrane of endothelial cells lining capillaries are called?

A

Fenestrations

32
Q

The largest blood vessels in the body are the…?

A

Elastic arteries

33
Q

At rest, a large portion of blood volume is kept in the systemic venules and…?

A

Veins

34
Q

Pressure-driven movement of blood from capillaries into interstitial fluid is known as?

A

Filtration

35
Q

The inner most layer of the tunica internal is called the what?

A

Endothelium