The Blood Vessels And Blood Pressure (Physiology) Flashcards

1
Q

What is meant by pressure gradient?

A

The pressure difference between the beginning and end of a blood vessel.

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2
Q

Three factors that determine vascular resistance?

A

Blood viscosity
Vessel length
Vessel radius

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3
Q

What is the relationship btwn flow of blood and pressure and resistance?

A

The rate of blood flow is directly proportional to the pressure gradient and inversely proportional to the vascular resistance.

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4
Q

What is the proportionality of resistance with respect to radius

A

Resistance is proportional to 1/r^4

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5
Q

Describe the BV of the vascular tree in coordination as well as which type of blood each carry.

A

Arteries- oxygenated
Arterioles- oxygenated
Capillaries- oxygenated
Venules- deoxygenated
Veins- deoxygenated

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6
Q

What do we call the microscopic exchange vessels with all cells, offering blood that supplies the metabolic needs of the cells?

A

Capillaries

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7
Q

What drives the flow of blood during cardiac relaxation?

A

The elastic coil in the walls of arteries

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8
Q

What happens in the arteries when blood is pumped into them?

A

They temporarily expand and when the heart relaxes, they passively recoil.

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9
Q

What is the mean arterial pressure?

A

It is the diastole pressure plus 1/3 of the pulse pressure

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10
Q

What are the major resistance vessels?

A

Arterioles

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11
Q

What are the local chemical and physical influences of resistance of arterioles?

A

Local metabolic changes and histamine release (chemical), Local heat and cold and myogenic responses to stretch ( physical).

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12
Q

Factors causing vasoconstriction(5)

A

-Increased myogenic activity.
- Increased oxygen
-Decreased CO2 and other metabolites
-Cold
-Vasopressins, angitensin 2, sympathetic stimulation.

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13
Q

Factors causing vasodilation

A

-Decreased myogenic activity.
- Decreased oxygen.
-Increased Co2 and other metabolites.
-Decreased sympathetic stimulation, vasopressins and angiotensin 2.
-Heat

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14
Q

What are the two influences or determinants of blood viscosity

A

Number of RBC.
Concentration of plasma proteins.

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15
Q

How does NA cause vasoconstriction in arterioles

A

By binding to the alpha 1 receptors.

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16
Q

True or false:
Sympathetic innervation is absent in arterioles.

A

False, it is parasympathetic innervation that is absent.

17
Q

Process responsible for the exchange of substances between blood and body cells

A

Diffusion

18
Q

How is the speed of blood flow in capillaries?

A

Slow

19
Q

Function of histamine

A

Increases capillary permeability

20
Q

What is the equation for determining BP?

A

BP=Cardiac output . Systemic vascular resistance

21
Q

What is the pressure that causes diffusion of nutrients from the capillary to interstitial fluid?

A

Hydrostatic pressure

22
Q

What is the pressure that pushes fluid movement into the capillaries?

A

Colloid osmotic pressure

23
Q

Which system is responsible for the return of interstitial fluid to the blood?

A

The lymphatic system

24
Q

Three extrinsic factors that enhance venous return

A

Increased sympathetic stimulation of the veins
Increased skeletal muscle activity.
Contraction of smooth muscle cells in the wall of the veins.

25
Q

Short-term mechanism for regulation of BP

A

Baroreceptor reflex

26
Q

Where do we find baroreceptors?

A

In the coronary sinus and aortic arch

27
Q

Explain how baroreceptors regulate blood pressure, eg when it is low.

A

Baroreceptors sense this change and they generate an action potential, using afferent pathway to the medulla.
The medulla then modifies the SNS and PSNS.
The PSNS is inhibited.
The SNS is stimulated and causes, increase in stroke volume, cardiac output (increased stroke volume and heart rate), total peripheral resistance by causing vasoconstriction.
This will ultimately increases the blood pressure until they are back to normal.

28
Q

Complications of hypertension include?(3)

A

Heart failure
Heart attack
Stroke

29
Q

What causes circulatory shock?

A

When BP drops to a point where blood flow is inadequate to serve the tissues.

30
Q

Name and explain the four types of circulatory shock.

A

Hypovolemic- Fall in blood volume.
Cardiogenic- caused by weakened heart.
Vasogenic- sudden widespread vasodilation caused by vasodilator substances.
Neurogenic- sudden widespread vasodilation but it is not caused by vasodilator substances.