L44: CVS 2

Question 1

Describe large arteries.

Answer 1

• Carry blood away from the heart to organs;
• Contain a small amount of blood at high pressure;
• Thick-walled, elastic.

Question 2

Describe arterioles.

Answer 2

• Resistance vessels;
• Variable resistance to distribute blood;
• Dissipate pressure.

Question 3

Describe capillaries.

Answer 3

• Exchange (gases/nutrients);
• Vast SA;
• As thin as one cell thick;
• Wide enough for one rbc.

Question 4

Describe venules.

Answer 4

For collection

Question 5

Decribe veins.

Answer 5

• Return blood to the heart;
• Collection and reservoir system (venules, veins, vena cava);
• 70% of blood at low pressure.

Question 6

What type of blood vessels do not contain vascular smooth muscle?

Answer 6

Smallest capillaries

Question 7

Which layer of vessel walls determines the vessel radius by contraction and relaxation?

Answer 7

Tunica media (smooth muscle)

Question 8

What risk does calcification to blood vessel elasticity?

Answer 8

• Elasticity is an important property to regulate pressure within blood vessels;
• During systole, these vessels act as pressure reservoirs;
• This prevents the pressure falling to 0 during diastole;
• Calcification reduces elasticity of the walls and effects BP.

Question 9

What is blood pressure (BP)?

Answer 9

Circulation of fluid contained within a space of a definite volume

Question 10

Why is there higher pressure in the left ventricle than the right ventricle?

Answer 10

Blood in the right ventricle is pumped to the lungs (pulmonary circulation) whereas blood in the left ventricle is pumped to the rest of the body (systematic circulation)

Question 11

Which ventricle has a thicker ventricle wall?

Answer 11

Left (blood pumped for systematic circulation)

Question 12

What is normal BP?

Answer 12

120/80 mmHg (SBP/DBP)

Question 13

What is mean arterial pressure (MAP)?

Answer 13

Average pressure pushing blood around the system:

MAP = DBP + 1/3 Pulse Pressure;
MAP = C.O. x TPR (total peripheral resistance)

Question 14

What factor favours movement of fluid OUT of blood capillaries?

Answer 14

Blood in the capillaries exerts a pressure on the capillary walls, hydrostatic pressure, this favours movement of fluid OUT

Question 15

What factor favours movement of fluid INTO blood capillaries?

Answer 15

Plasma has an intrinsic osmotic pressure due to the plasma proteins (colloid pressure), this favours fluid movement INTO capillaries

Question 16

What system drains excess fluid from tissues?

Answer 16

Lymphatic system

Question 17

Describe the relationship between arterial and venous pressures.

Answer 17

• Hydrostatic pressure drops as BP drops;
• Colloid pressure stays the same as proteins are too big to leave capillary walls;
• Fluid will move OUT at the arterial end and IN at the venous end where CP>HP;
• This is physiologically favoured.

Question 18

How do pulmonary pressures differ to systematic pressures?

Answer 18

• Pulmonary pressures are lower;
• CP are equivalent;
• Net fluid transfer at both ends;
• Prevents pulmonary oedema.

Question 19

How do decongestants work?

Answer 19

Vasoconstriction of mucosal blood vessels by release of endogenous NA