Week 4 Tutorial

Question 1

What is blood pressure

Answer 1

What is blood pressure?
• Force exerted on walls of blood vessels
• Usually arteries
Average = 120/75 mmH

Question 2

What is blood pressure measured in

Answer 2

Millimetres of mercury

Question 3

Two measures of blood pressure

Answer 3

Two measures:
Systolic = During ventricular systole
Diastole = During ventricular diastole

Question 4

What is pulse pressure

Answer 4

Systolic - diastolic

Question 5

Mean arterial pressure what is it

Answer 5

Average blood pressure during a single cardiac cycle

Question 6

How is mean arterial pressure calculated

Answer 6

How is it calculated?
Cardiac output (Q) x peripheral resistance (PR)
• OR
Diastolic pressure + 1/3 (systolic pressure- diastolic pressure)

Question 7

Given a cardiac output of 5 L/min, a systolic pressure of 120 mmH, and a diastolic pressure of 80 mmg, calculate the Mean Arterial Pressure

Answer 7

80+1/3*(40)
=93.3 mmHg

Question 8

Blood flow- definition

Answer 8

“What does blood flow describe?
The volume of blood flowing through the body’s vessels at any given time (mL / min)

Question 9

Circulation time

Answer 9

What is circulation time?
• The time it takes for blood to go from right atrium back to right atrium
• typically takes 1 minute

Question 10

Velocity of blood flow

Answer 10

What is velocity of blood flow?
Speed at which a volume of blood flows through a given tissue.

Question 11

Determinants of blood pressure

Answer 11

Peripheral resistance
- length of vessels
- diameters of blood vessels
- blood viscosity

• cardiac output(Q) =HR (heart rate)x SV(stroke volume)
• blood volume ( controlled by kidneys)

Question 12

Stroke volume

Answer 12

How much is being pumped each beat

SV = EDV - ESV

Governed by (3 things):
- preload
- initial stretching of cardiac myocytes( heart wall)
- contractility
- afterload

Question 13

Frank starling law

Answer 13

Volume of blood in heart is proportional to the amount of blood pumped each stroke

Allows the heart to adjust to varying levels of venous return (the amount of blood returning to the heart from the body) and maintain a relatively constant output. For instance, during exercise, venous return increases.
This causes the ventricles to stretch, leading to stronger contractions and a higher stroke volume, enabling the heart to pump more oxygenated blood to the muscles that need it.

Question 14

Contractility

Answer 14

Agents that increase contractility
Positive inotropic
- Calcium
- Catecholamines
•Epinephrine and Noepinephrine
-Glucagon

Agents that decrease contractility
Negative inotropic
- Potassium

Question 15

Blood vessels

Answer 15

Arteries carry blood away from heart

Veins carry blood back to heart

Capilaries connect smallest arteries to veins

Question 16

Capillaries

Answer 16

The most common type of capillary, the Continuous capillary, is found in almost all vascularized tissues

A Fenestrated capillary is one that has pores (or fenestrations)

A sinusoid capillary (or sinusoid) is the least common type of capillary

Question 17

During exercise, there are several changes that occur within the body to ensure that the working muscles are adequately supplied with oxygen id nutrients. These changes are typically regulated by the autonomic nervous system and include a variety of cardiovascular and emodynamic alterations. Some of the key changes:

Answer 17

Increased blood flow = increased 02/ CO2 exchange
1. Increased HR
2. Increased venous return
3. Increased stroke volume
4. Increased cardiac output
5. Increased blood pressure
6. Vasomotion
1. Vasodilation in skeletal muscle
2. Vasoconstriction- Gl tract