Vascular System.

Question 1

List the Characteristics of Arteries.

Answer 1

Narrow Lumen.
No Valves.
High Pressure.
Thick, Muscular Walls.
Smooth Inside Layer.

Question 2

What is the Function of Arteries?

Answer 2

Take blood away from the heart.

Question 3

List the Characteristics of Veins.

Answer 3

Wide Lumen.
Valves,
Low Pressure.
Thin Walls.
No Smooth Layer.

Question 4

What is the Function of Veins?

Answer 4

Bring blood towards the heart

Question 5

Define Valves.

Answer 5

Prevent the backflow of blood.

Question 6

Define Venous Return.

Answer 6

Blood returning back to the heart in the veins.

Question 7

List the Venous Return Mechanisms.

Answer 7

Pocket Valves.
Skeletal Muscle Pump.
Respiratory Muscle Pump.
Smooth Muscle.
Suction Pump at Right Atrium.
Gravity.

Question 8

Describe Pocket Valves.

Answer 8

Allow one-way blood flow, and close to prevent back flow.

Question 9

Describe Skeletal Muscle Pump.

Answer 9

As muscles contract.
Squashes the veins.
Increases pressure in the vein.
Forces blood out towards the heart.

Question 10

Describe Respiratory Muscle Pump.

Answer 10

Changes in thoracic and amdominal pressure when breathing in and out.
Squash the surrounding veins.
Increases pressure in the vein.
Forces blood out towards the heart.

Question 11

Describe Smooth Muscle.

Answer 11

Veins have thin walls, but the muscle that is there can contract/twitch to increase pressure

Question 12

Describe Suction Pump at Right Atrium.

Answer 12

As right atrium relaxes, this pressure change ‘sucks’ blood in.

Question 13

Describe Gravity.

Answer 13

If above the heart.

Question 14

During exercise, there is an increase in Venous return. This means…

Answer 14

Greater filling of the heart.
Cardiac muscles stretch more.
The resulting force of contraction is increased.
Increased stroke volume/ejection fraction.

Question 15

List Vascular Shunt Mechanisms.

Answer 15

Vasodilation.
Vasoconstriction.

Question 16

Define Vasodilation.

Answer 16

Lumen of the blood vessel gets wider.

Question 17

Why does Vasodilation happen in the Working Muscles?

Answer 17

The working muscles require more oxygen to produce more energy.
So, blood flow is increased to meet this increase in oxygen demand.

Question 18

Why does Vasodilation happen at the Heart?

Answer 18

The heart needs a greater supply of oxygen because it works harder.

Question 19

Why does Vasodilation happen in the Skin?

Answer 19

Blood is directed to the skin to cool the body down. By being nearer the skin, the blood can cool via convection of the outside air and radiation closer to the surface.

Question 20

Define Vasoconstriction.

Answer 20

Lumen of the blood vessel narrows.

Question 21

Why does Vasoconstriction happen in the Digestive Organs?

Answer 21

During exercise, the priority is not on digesting food, but on providing blood and oxygen to the places that need it.

Question 22

Define AVO2 Difference.

Answer 22

The difference in oxygen content between the blood in the arteries and blood in the veins.

Question 23

Explain what happens to AVO2 following the onset of Exercise.

Answer 23

During exercise, our muscles need more oxygen to keep up with the increased demand.
AVO2 Increases because our muscles extract more oxygen from the blood.

Question 24

Define Bohr Shift.

Answer 24

A downwards and right shift of the oxyhaemoglobin dissociation curve (any given place/point).
Haemoglobin is less saturated with oxygen.

Question 25

List the Effects of Bohr Shift during Exercise.

Answer 25

Increased demand for Oxygen. Increase in Temperature. Increase in Acidity. Increase in CO2.

Question 26

Describe the Increased demand for Oxygen.

Answer 26

Tissues take more oxygen out of the haemoglobin, which is why there is less on the haemoglobin.

Question 27

Describe the Increase in Temperature.

Answer 27

In hotter temperatures, oxygen dissociates from haemoglobin more readily.

Question 28

Describe the Increase in Acidity.

Answer 28

Exercise causes a little bit of acidity, which denatures the haemoglobin, therefore oxygen dissociates more readily.

Question 29

Describe the Increase in CO2.

Answer 29

Haemoglobin has a higher affinity for CO2 than oxygen. More CO2 is produced during exercise, creating carboxyhaemoglobin instead.

Question 30

Describe how the body redistributes blood to the skeletal muscles during exercise.

Answer 30

The body redistributes blood to the skeletal muscles to provide them with oxygen and nutrients. This is because the muscles need more energy and oxygen to perform physical activity. The heart pumps more blood, and the blood vessels in the muscles dilate to allow for increased blood flow. This helps deliver oxygen and nutrients to the working muscles and remove waste products like carbon dioxide.