4.1 - Overview: Cardiovascular System & The Heart

Question 1

What do multi cellular organisms require from the environment?

Answer 1

• Nutrients

- Oxygen

Question 2

Rate of diffusion of O2 and nutrients is limited by distance. How do we overcome this?

Answer 2

• cardiovascular system transports substances through the body
• transported by flow of blood through circulatory system
• bulk flow rather than diffusion

Question 3

Explain how materials are transported throughout the body

Answer 3

• from external environment to tissues: nutrients, water, gases (e.g. O2)
• b/w tissues of body: wastes, nutrients, hormones
• from tissues to external environment: metabolic wastes, heat, gases (e.g. CO2)

Question 4

Name the components of the cardiovascular system:

Answer 4

• heart: pump
• blood vessels: vasculature
• blood cells and plasma: fluid

Question 5

What makes up the external anatomy of the heart?

Answer 5

• Pericardium

- Coronary arteries

Question 6

What is the pericardium? What is it made up of?

Answer 6

• tough membranous sac surrounding the heart

- made up of 2 layers with a small amount of fluid between them (pericardial fluid: lubricant)

Question 7

What is the function of the coronary arteries and why are they important?

Answer 7

• nourishes the heart muscle

- heart has a very high O2 demand: depends heavily on adequate supply of blood flow

Question 8

Another term for a heart attack

Answer 8

myocardial infarction

Question 9

The lack of blood supply to heart can lead to?

Answer 9

heart attack

Question 10

What makes up the internal anatomy of the heart?

Answer 10

• left atrium: receives blood from the pulmonary veins, sends to left ventricle (O2 rich blood)
• Left ventricle: receives blood from left atrium, sends blood to body via aorta
• Right atrium: receives blood from venae cavae, sends to right ventricle
• Right ventricle: receives blood from right atrium, sends to lungs via pulmonary arteries

Question 11

What are the functions of valves in the internal anatomy of the heart?

Answer 11

• ensures blood flow is uni-directional (one-way)

Question 12

TRUE OR FALSE:

The right and left atrium both have valves at their entrances

Answer 12

FALSE; none have valves at entrance

Question 13

Why are valves absent at the entrance of the right and left atriums?

Answer 13

Due to weak atrial contraction relative to ventricular contraction

Question 14

What happens to veins during atrial contraction?

Answer 14

• veins at the entry to the heart are compressed: closes exit to the heart and reduces backflow

Question 15

Where are AV valves attached?

Answer 15

• attached on ventricular side to collagenous cords (chordae tendinae)
• chords prevent valves from being pushed back into atrium

Question 16

Name the AV valves

Answer 16

• tricuspid (right ventricle)

- bicuspid (mitral: left ventricle)

Question 17

What are the 2 types of semi lunar valves? What are their functions?

Answer 17

• pulmonary
• aortic
• prevent backflow of blood into ventricles

Question 18

TRUE OR FALSE:

Semi lunar and AV valves do not needs chords to brace them

Answer 18

FALSE:

• semi lunar valves do not need chords due to their shape
• AV valves need chords

Question 19

What are the 2 pathways for blood in the cardiovascular system?

Answer 19

• pulmonary circuit

- systemic circuit

Question 20

What makes up the pulmonary circuit?

Answer 20

blood vessels in the lungs and those connecting the lungs to the heart

Question 21

What is the path of blood flow of the pulmonary circuit?

Answer 21

• right atrium, right ventricle, pulmonary arteries to lungs

- oxygenated blood return to heart via pulmonary veins to left atrium

Question 22

How is blood oxygenated in the lungs?

Answer 22

• Lungs have small capillaries to increase O2 transfer

- small radius, high surface area: increases resistance, decrease blood pressure

Question 23

What makes up the systemic circuit?

Answer 23

the rest of the blood vessels of the body

Question 24

What is the path of blood flow of the systemic circuit?

Answer 24

• left atrium, left ventricle, to aorta, branches into smaller arteries, branches to capillaries throughout body
• O2 diffuses from blood in tissues into capillary beds, flow to small venules, then larger veins

Question 25

How does O2 poor blood return back to the heart?

Answer 25

Via superior vena cava and inferior vena cava, to right atrium

Question 26

TRUE OR FALSE:

Both O2 high blood and O2 low blood have high pressure

Answer 26

FALSE

both have low pressure

Question 27

When is the blood pressure increased?

Answer 27

At critical points in the double cycle