A&P - Chapter 30 (Part 1)

Question 1

Hemodynamics

Answer 1

Refers to the numerous mechanisms that influence the dynamics of the circulation of the blood

Question 2

What is hemodynamics essential for? (2)

Answer 2

1. Health

2. Survival

Question 3

What must the circulation control mechanism do? (2)

Answer 3

1. Maintain circulation

2. Vary the volume and distributing of blood circulated

Question 4

What are the 2 primary principles of circulation?

Answer 4

1. A fluid doesn’t flow when the pressure is the same throughout the system
2. A fluid flows only when its pressure is higher in one area than in another, and it flows from its higher pressure area to its lower pressure

Question 5

What kind of gradient moves blood?

Answer 5

Pressure gradient

Question 6

What is blood pressure?

Answer 6

A push or force of blood in the blood vessels

Question 7

Where is blood pressure highest?

Answer 7

In arteries

Question 8

What is arterial blood pressure directly proportional to?

Answer 8

Arterial blood volume

Question 9

What are the 2 main factors that determine arterial blood pressure?

Answer 9

1. Cardiac output

2. Peripheral resistance

Question 10

Cardiac output

Answer 10

Is the amount of blood that flows out of a ventricle of the heart per unit of time

Question 11

What does cardiac output influence?

Answer 11

The flow rate to various organs of the body

Question 12

Stroke volume

Answer 12

The volume of blood pumped out of a ventricle by each beat

Question 13

What is cardiac output determined by? (2)

Answer 13

1. Stroke volume

2. Heart rate

Question 14

What is the formula for cardiac output?

Answer 14

Stroke volume (vol/beat) x heart rate (beat/min)

Question 15

What is the units for cardiac output?

Answer 15

volume/min

Question 16

What is something that can affect cardiac output? (2)

Answer 16

1. Neurotransmitters

2. Hormones

Question 17

What does thyroid hormone do to the heart?

Answer 17

Speeds up the heart rate

Question 18

What does the acetylcholine do to the heart?

Answer 18

Slows down the heart rate

- parasympathetic

Question 19

What are 3 factors that affect stroke volume?

Answer 19

1. Strength of myocardial contractions
2. Neurotransmitters
3. Hormones

Question 20

Starlings Law of the Heart

Answer 20

The more stretched out the heart muscle fibres are at the beginning of a contraction, the stronger the contraction will be

Question 21

What are 8 factors that affect heart rate?

Answer 21

1. Autonomic nervous system innervation
   - sympathetic vs. parasympathetic
2. Cardiac presoreflexes
3. Emotions
4. Exercise
5. Hormones
6. Blood temperature
7. Pain
8. Stress

Question 22

Peripheral resistance

Answer 22

Any force that acts against the flow of blood

Question 23

Vasoconstriction

Answer 23

Tension in the muscles of the blood vessel walls are contracted and resistance is high

Question 24

Vasodilation

Answer 24

Tension in the muscles of the blood vessel walls are relaxed and resistance is low

Question 25

Where is the vasomotor centre located?

Answer 25

In the medulla

Question 26

What does the vasomotor centre stimulate?

Answer 26

Constriction of blood vessels

Question 27

Where are the vasomotor chemoreflexes located?

Answer 27

Same location as the stretch receptors

Question 28

What are vasochemoreflexes sensitive to? (3)

Answer 28

1. Excess carbon dioxide in the blood
2. Low oxygen
3. Decreased arterial pH