Blood pressure and cardiac output

Question 1

State the name AND location of the cardiac control centre

Answer 1

Cardiovascular centre: The cardiac control centre in the medulla oblongata controls the rate and force of the heart contraction
The vasomotor centre in the medulla oblongata controls the diameter of blood vessels.

Question 2

Define a baroreceptor

Answer 2

pressure receptors that respond rapidly to maintain homeostasis during short-term or acute changes in the blood pressure.

Question 3

State the two key locations where these are found

Answer 3

• Carotid arteries
• Aortic arch

Question 4

State the functions of blood pressure

Answer 4

1. Blood pressure pushes blood through blood vessels
2. Filtration of blood through the kidneys
   3.Drives capillary exchange between blood and cells (gas exchange)

Question 5

List four factors which influence blood pressure

Answer 5

• Peripheral resistance
• Blood vessel diameter
• Cardiac Output
• Blood viscosity
• Blood vessel length

Question 6

Define: systole

Answer 6

systole; the part of the cardiac cycle during which some chambers of the heart contract after refilling with blood.

Question 7

Define: diastole

Answer 7

diastole; the relaxed phase of the cardiac cycle when the chambers of the heart are refilling with blood.

Question 8

Define: Mean Arterial Pressure (MAP)

Answer 8

MAP - is the calculation to check if there is enough, blood flow, resistance, and pressure to supply blood to all major organs.

Question 9

Define: systolic BP

Answer 9

systolic BP: is the higher pressure measured during left ventricle systole

Question 10

Define: diastolic BP

Answer 10

diastolic BP: is the lower pressure measured during left ventricular diastole

Question 11

Define cardiac output:

Answer 11

cardiac output is the amount of blood pumped out by the ventricle in a minute

Question 12

State the equation -

Answer 12

CO = SV x HR

Question 13

Define stroke volume:

Answer 13

stroke volume - is the volume of blood ejected from one ventricle every beat

Question 14

List the three factors which can potentially affect stroke volume:

Answer 14

1. Preload - The amount of blood in the ventricle before it contracts, also known as end diastolic volume
2. Afterload - The resistance ventricles must overcome to circulate blood
3. Contractility - How strongly the ventricle can contract

Question 15

Describe the relationship between blood viscosity and blood pressure

Answer 15

Viscosity = the ‘thickness’ of blood

• Increased blood viscosity causes increased BP
• Dehydration or increased haematocrit increases BP

Question 16

State when adrenaline is released

Answer 16

Adrenaline and noradrenaline are released in emergency situations, these are hormones which enhance the response of the sympathetic nervous system.

Question 17

State three ways adrenaline increases blood pressure:

Answer 17

• Increasing heart rate and force of contraction
• Constricting many arterioles
• Increasing venous pressure

Question 18

Describe the role of the renal system in maintaining blood pressure

Answer 18

Blood volume is a major determinant of cardiac output
The kidneys control blood volume by increasing urine output when blood volume is higher
RAAS - changes blood plasma volume

Question 19

List seven age related changes to the cardiovascular system:

Answer 19

• Decreased compliance of Aorta
• Loss of cardiac muscle size and strength (decreased cardiac output)
• Increase in systolic BP
• Increase in total blood cholesterol
• Increase in coronary artery disease (major cause of death)
• Congestive heart failure (impaired pumping of the heart)
• Atherosclerosis damage to blood vessels reduces blood supply to brain and kidneys (malfunction or death of brain cells)

Question 20

ADH AND RASS

Answer 20

• ADH and RASS tend to increase water retention and increase total plasma volume

Question 21

ANP

Answer 21

• ANP promote water loss and decrease in total plasma volume