6- Vasculature 2

Question 1

4 Factors Affecting Blood Flow?

Answer 1

Blood pressure
Vascular resistance
Venous return
Velocity of blood flow

Question 2

Blood pressure (BP) is defined as…?

Answer 2

the hydrostatic pressure exerted by blood on the walls of blood vessels

Question 3

When does a systole occur?

Answer 3

when the heart contracts to pump blood out

Question 4

When does a dyastole occur?

Answer 4

when the heart relaxes after contraction

Question 5

Systolic blood pressure is ..?

Answer 5

the highest pressure attained in arteries during systole

Question 6

Diastolic blood pressure is…?

Answer 6

the lowest arterial pressure during diastole

Question 7

What is Mean arterial pressure MAP and how is it calculated?

Answer 7

the average blood pressure in arteries

MAP = diastolic BP + 1/3 (systolic BP - diastolic BP)

Question 8

What is vascular resistance?

Answer 8

friction between blood and the walls of blood vessels (opposition to blood flow)

Increased vascular resistance will increase blood pressure

Question 9

What is a lumen?

Answer 9

the inside space of a tubular structure

Question 10

3 factors affecting vascular resistance?

Answer 10

Size of the blood vessel lumen
Blood viscosity
Total blood vessel length

Question 11

What is systemic vascular resistance (SVR) –also known as total peripheral resistance (TPR)

Answer 11

all the vascular resistances offered by systemic blood vessels

Question 12

Venous return depends on what?

Answer 12

Pressure difference from venules
Skeletal muscle pump
Respiratory pump

Question 13

What is a skeletal muscle pump?

Answer 13

the contraction and relaxation of skeletal muscles allowing for the opening and closure of venous valves which pumps the blood towards the heart

Question 14

What is a respiratory pump?

Answer 14

the movement of the diaphragm with breathing which causes changes in thoracic pressure and abdominal pressure.

This helps with the opening and closure of venous valves.

Question 15

What is circulation time?

Answer 15

the time required for a drop of blood to pass from the RIGHT TRIUM,
through the PULMONARY CIRCULATION, back to the LEFT ATRIUM, through the SYSTEMIC CIRCULATION down to the foot, and back again to the RIGHT ATRIUM

(approx 1 minute at rest)

Question 16

What is the cardiovascular centre (CV)?

Answer 16

A group of neurons in the medulla oblongata that regulates the heart rate, contractility, and blood vessel diameter.

Question 17

The cardiovascular system receives input from where?

Answer 17

higher brain regions

sensory receptors: proprioceptors, baroreceptors and chemoreceptors.

Question 18

Baroreceptors are..?

Answer 18

pressure-sensitive sensory neurons located in the aorta, internal carotid arteries and other large arteries in the neck and chest

Question 19

The main baroreceptor reflexes are:

Answer 19

the carotid sinus reflex
(maintains normal blood pressure in the brain)

the aortic reflex
(maintains general systemic blood pressure)

Question 20

Chemoreceptor reflexes are…?

Answer 20

sensory receptors that monitor the chemical composition of blood

located close to the baroreceptors of the carotid sinus (carotid bodies) and arch of the aorta (aortic bodies).

Question 21

Name 4 hormones that alter cardiac output

Answer 21

Renin-angiotensin-aldosterone system
Epinephrine and norepinephrine
ADH (Antidiuretic hormone)
ANP (atrial natriuretic peptide)

Question 22

Explain the renin-angiotensin-aldosterone system

Answer 22

Renin is released from renal cells in response to a decrease in blood volume or a decrease in the blood flow to the kidneys. This results in a formation of angiotensin II which raises blood pressure through systemic vasoconstriction but also causes the release of aldosterone (which increases the H2O and Na+ reabsorption from the kidneys).

Question 23

Epinephrine and norepinephrine are released from..?

What do they do?

Answer 23

the adrenal medulla

increase the heart rate and force of contraction, cause vasoconstriction in the skin and abdominal organs, and vasodilation in cardiac and skeletal muscle.

Question 24

ADH (Antidiuretic hormone) is released from..? in response to?

Answer 24

the posterior pituitary in response to dehydration or decreased blood volume. This causes vasoconstriction

Question 25

ANP (Atrial Natriuretic Peptide) is released by …?

it causes..?

Answer 25

cells in the atria of the heart when blood pressure rises.

This causes vasodilation and promotes the loss of salt and water in the urine.

Question 26

normal pulse rate in a healthy person?

Answer 26

70-80 beats/min at rest.

Question 27

Define tachycardia and bradycardia

Answer 27

Tachycardia is a condition where the pulse rate is over 100 beats/min

Bradycardia is a condition when the pulse rate under 60 beats/min

Question 28

Blood pressure is measured with what?

Answer 28

sphygmomanometer

Question 29

What can you hear with a sphygmomanometer?

Answer 29

Korotkoff sounds: The various sounds that are heard while taking blood pressure

Systolic blood pressure: Blood pressure on arterial walls just after ventricular contraction

Diastolic blood pressure: Blood pressure in arteries during ventricular relaxation

Pulse pressure: The difference between systolic and diastolic.
(The normal ratio is 3:2:1 - systolic/diastolic/pulse pressure)

Question 30

What are the 3 branches of the aorta?

Answer 30

Ascending aorta
Arch of the aorta
Descending aorta (thoracic and abdominal)

Question 31

What is mesentry?

Answer 31

tissue that attaches organs to the body wall

Question 32

All venous blood drains to which 3 veins?

Answer 32

superior vena cava
inferior vena cava
coronary sinus

Question 33

All major systemic veins empty into which part of the heart?

Answer 33

the right atrium

Question 34

What is the function of the hepatic portal circulation?

Answer 34

to collect blood from the veins of the pancreas, spleen, stomach, intestines and gallbladder to direct it into the hepatic portal vein of the liver before returning it to the heart

To enable nutrient utilisation and blood detoxification by the liver.

Question 35

What is the pathway of the hepatic portal circulation?

Answer 35

The abdominal aorta transports blood from the heart to the proper hepatic artery and then to the liver. It then goes back via the hepatic veins and the inferior vena cava to the heart.

Tributaries from the stomach pancreas and large intestines drain into the splenic vein which drains into the hepatic portal vein.

Tributaries from the small intestine, stomach and the pancreas drain to the superior mesenteric vein to the portal vein. The hepatic portal vein drains into the liver.