4 - Blood Vessels Flashcards

1
Q

Describe layers of blood vessel wall

A

1) Tunica Externa: Connective tissue
2) Tunica Media: smooth muscle, allowing vasoconstiction and dilation
3) Tunica Intima: smooth muscle

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2
Q

What are the 5 types of capillary bases

A

1) Continuous
2) Fenestrated
3) Sinusoidal
4) Sinusoids
5) Venous Sinuses

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3
Q

Continuous Capillary (function and location)

A

1 – Continuous: No gaps between endothelial cells. No fenestrae. Less permeable to large molecules. E.g. muscle and nervous tissue.

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4
Q

Fenestrated - function + location

A

2 – Fenestrated. Have pores, numerous fenestrae. Highly permeable. E.g. intestinal villi, glomeruli of kidney.

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5
Q

Sinusoidal - function + location

A

3 – Sinusoidal: large in diameter with large fenestrae. Less basement membrane. E.g. endocrine glands (large molecules cross their walls)

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6
Q

Sinusoids - function + location

A

4 – Sinusoids: large diameter. Sinusoidal capillaries. Sparse basement membrane. E.g.. liver, bone marrow.

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7
Q

Venous Sinuses - function + location

A

5 – Venous sinuses: Similar structure to sinusoids but even larger. E.g. spleen

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8
Q

What is fenestrae?

A
  • FENESTRAE: are areas where cytoplasm is absent and plasma membrane is made of thin, porous diaphragm.
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9
Q

▪ Define vasoconstriction and vasodilation

A

▪ Vasoconstriction: smooth muscles contract, decreasing blood flow.

▪ Vasodilation: smooth muscle cells relax and increase blood flow.

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10
Q

▪ Define the term vasa vasorum

A

Vasa Vasorum: blood vessels that supply the walls of the arteries and veins. Penetrate the vessel walls from the exterior, branches of the arteries.

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11
Q

▪ Define the term portal veins

A

Portal Veins: Veins that begin in a primary capillary network, extending some distance and end in a secondary capillary network without a pumping mechanism.

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12
Q

What type of nerve fibres are blood vessels innervated by?

A

Sympathetic fibres

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13
Q

Arterial changes that occur with age

A

Arteriosclerosis: degeneration changes in arteries, making them less elastic.

Atherosclerosis: depiction of plaque on walls

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14
Q

How does odema occur?

A

Odema occurs when capillary walls become permable and allow proteins to leak from the capillary into its instersitial fluid

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15
Q

What are the factors effecting blood flow

A
  • Blood pressure
  • Flow
    Resitance
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16
Q

What is blood pressure

A

force exerted by blood against vessel wall

17
Q

What is blood pressure measured by?

A

Korotkoff sounds

18
Q

What is normal blood pressure

A

120/80

19
Q

How do you calculate flow?

A

P1-P2 (P represents a specific point in a unit of time)

20
Q

How is a Korotoff sound produced?

A

By TURBULANT flow

21
Q

What is laminar flow?

A

Streamlined flow - outermost layer is the slowest and innermost is the fastest

22
Q

What is turbulant flow

A

Interupted flow due to rpughened surface (e.g. from a pressure cuff)

23
Q

What is Poiseluilles law?

A

Flow increases when resistance increases (e.g. when exercising)

24
Q

How does viscosity effect bloodflow pressure

A

Viscosity increases blood flow pressure

25
Q

What is critical closing pressure

A

A pressure at which a blood vessel collapses and blood flow stops

26
Q

What is Laplace’s Law

A

Force acting on blood vessel is proportional to diameter of vissel x blood pressure

27
Q

What is vascular compliance?

A

Blood vessel volume increases as pressure increases

28
Q

What is pulse pressure?

A

Increases when stroke volume increases or vascular compliance decreases. Compliance decreases with age

29
Q

What are the pressures involved in fluid exchange across capillary walls?

A

1) Capillary Exchange

2) Net Filtration Pressure

30
Q

What do baroreceptors do?

A

Detect changes in blood pressure, and if low = will cause increased sympathetic stimulation of blood vessels = vasoconstiction

31
Q

What do chemoreceptors do?

A

Monitor blood O2, CO2 and pH levels of blood.

32
Q

What is the CNS ischemic response?

A

Due to high CO2 or low pH levels

33
Q

What happens in the renin-angiotensingen mechanism?

A

Decreased blood pressure = results in increased H2O reabsoption, decreased urine volume = increased blood pressure.

34
Q

What happens in the ADH mechanism

A

Osmoreceptors detect changes in osmolarity
Baroreceptors detect changes in blood pressure
> ADH secretion
= increase Blood volume and increased blood pressure

35
Q

What is the atrial natriuretic mechanism?

A

Osmorecptors = detect increased osmotic pressre
Baroreceptors detect decreased BP

= ADH secretion

= Increased BV and BP