B3 The Circulatory System Review

Question 1

What are the main functions of the circulatory system?

Answer 1

1. Transport gases, nutrients, wastes and hormones (O2, CO2)
2. Regulates internal temperature
3. Protects against microbes (pathogens) and toxic substances

Question 2

What are the 3 main components of the circulatory system?

Answer 2

1. Heart
2. Blood vessels
3. Blood

Question 3

What are the 3 blood vessels?

Answer 3

1. Arteries
2. Veins
3. Capillaries

Question 4

Describe an Artery

Answer 4

-Carry blood from the heart to the body/lungs
-has highly elastic walls to allow the artery to expand
-thin to arterioles [mini arteries]

Question 5

What is pulse?

Answer 5

-It’s a measure of the rhythmic expansion and contraction of an artery as blood moves through it

Question 6

Describe a vein

Answer 6

-Veins carry blood from the body/lungs to the heart
-thinner walls then arteries and a larger inner circumference
-not elastic
-move blood to the heart by one way valves and skeletal muscle contractions
-venules expand to veins

Question 7

Describe a capillary

Answer 7

-Where gases and other materials are transferred from blood to tissues and vice versa
-smallest blood vessels
-diameter is a single cell layer
-spread through the body in a network

Question 8

What is a pulmonary pathway?

Answer 8

-Transport oxygen poor blood to the lungs

Question 9

Describe the heart

Answer 9

-4 chambered
-made of cardiac muscle
-contractions are rhythmic and involuntary

Question 10

Describe the right side of the heart

Answer 10

-Right side of the heart receives blood from the body (deoxygenated) through the vena cava and pumps it to the lungs via the pulmonary artery

Question 11

What are pulmonary arteries?

Answer 11

-Only arteries which contain oxygen poor blood (all other arteries are oxygenated)

Question 12

Describe the left side of the heart

Answer 12

-Left side of the heart receives blood from the lungs via the pulmonary veins and pumps it to the body through the aorta

Question 13

What are pulmonary veins?

Answer 13

-Only veins which contain oxygen rich blood (all other veins are deoxygenated)

Question 14

What is the sinoatrial node?

Answer 14

-Stimulates the muscle cells to contract and relax rhythmically (pace maker)
-in the wall of the right atrium

Question 15

How does the heart contract?

Answer 15

1. An electrical signal from the SA node spreads over the 2 atria and make them contract simultaneously
2. As the atria contract, the signal reaches the atrioventricular node
3. Electrical signal then proceeds through the bundle of his
4. Fibers relay the signal through the 2 branches called purkinje fibers
5. Stimulates contractions of the ventricles

Question 16

What is an ECG (electrocardiogram)?

Answer 16

-Change in voltage produced by the electrical signal
-electrical system
-“lub”: closing of AV valves during ventricular contraction
-“dub”: closing of semilunar valves during ventricular relaxation
-heart murmur caused by valves not closing properly

Question 17

What is blood pressure?

Answer 17

-The pressure exerted against the vessel (arteries) walls by blood
-measured using a sphygmomanometer (blood pressure cuff)
-average is 120/80
-high blood pressure is also called hypertension

Question 18

What is systolic pressure?

Answer 18

-Maximum pressure during ventricular contraction
-top of the fraction representing blood pressure

Question 19

What is diastolic pressure?

Answer 19

-Lowest pressure during ventricular relaxation
-bottom of the fraction representing blood pressure

Question 20

What are baroreceptors?

Answer 20

-Blood pressure receptors
-in the walls of the Aorta and carotid arteries
-monitor blood pressure and signal heart to beat with more or less force

Question 21

What is cardiac output?

Answer 21

-Amount of blood pumped by the heart per minute (mL/min)
-indicates the level of oxygen delivered to the body
-~4900 mL/min for the average person

Question 22

What is heart rate?

Answer 22

-Number of heart beats per minute
-low resting heart rate is considered an indicator of cardiovascular fitness (if heart rate is low then stroke volume must be high)

Question 23

What is stroke volume?

Answer 23

-Amount of blood forced out of the heart with each heart beat (mL per beat)
-average is ~70 mL per beat