The Blood Vessels And Blood Pressure (Physiology)

Question 1

What is meant by pressure gradient?

Answer 1

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

Question 2

Three factors that determine vascular resistance?

Answer 2

Blood viscosity
Vessel length
Vessel radius

Question 3

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

Answer 3

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

Question 4

What is the proportionality of resistance with respect to radius

Answer 4

Resistance is proportional to 1/r^4

Question 5

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

Answer 5

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

Question 6

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

Answer 6

Capillaries

Question 7

What drives the flow of blood during cardiac relaxation?

Answer 7

The elastic coil in the walls of arteries

Question 8

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

Answer 8

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

Question 9

What is the mean arterial pressure?

Answer 9

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

Question 10

What are the major resistance vessels?

Answer 10

Arterioles

Question 11

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

Answer 11

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

Question 12

Factors causing vasoconstriction(5)

Answer 12

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

Question 13

Factors causing vasodilation

Answer 13

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

Question 14

What are the two influences or determinants of blood viscosity

Answer 14

Number of RBC.
Concentration of plasma proteins.

Question 15

How does NA cause vasoconstriction in arterioles

Answer 15

By binding to the alpha 1 receptors.

Question 16

True or false:
Sympathetic innervation is absent in arterioles.

Answer 16

False, it is parasympathetic innervation that is absent.

Question 17

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

Answer 17

Diffusion

Question 18

How is the speed of blood flow in capillaries?

Answer 18

Slow

Question 19

Function of histamine

Answer 19

Increases capillary permeability

Question 20

What is the equation for determining BP?

Answer 20

BP=Cardiac output . Systemic vascular resistance

Question 21

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

Answer 21

Hydrostatic pressure

Question 22

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

Answer 22

Colloid osmotic pressure

Question 23

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

Answer 23

The lymphatic system

Question 24

Three extrinsic factors that enhance venous return

Answer 24

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

Question 25

Short-term mechanism for regulation of BP

Answer 25

Baroreceptor reflex

Question 26

Where do we find baroreceptors?

Answer 26

In the coronary sinus and aortic arch

Question 27

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

Answer 27

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.

Question 28

Complications of hypertension include?(3)

Answer 28

Heart failure
Heart attack
Stroke

Question 29

What causes circulatory shock?

Answer 29

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

Question 30

Name and explain the four types of circulatory shock.

Answer 30

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.