Lesson 1: Blood Vessels

Question 1

what is the circulatory system

Answer 1

it is how the body transports its molecules at the extracellular level(using the heart, blood vessels and blood)

Question 2

what is the FUNCTION of the circulatory system

Answer 2

to deliver nutrients, remove wastes, transport signal molecules and immune cells and more

Question 3

what are large blood vessels that move AWAY from the heart called

Answer 3

arteries

Question 4

what are smaller blood vessels that move AWAY from the heart called

Answer 4

arterioles

Question 5

what are large blood vessels that move TOWARDS the heart called

Answer 5

veins

Question 6

what are smaller blood vessels that move TOWARDS the heart called

Answer 6

venules

Question 7

what are capillaries and what is their use

Answer 7

tiny blood vessels that exchange nutrients with its surrounding cells

Question 8

explain how the circulatory system is cyclic

Answer 8

blood flows in a circuit starting in the heart, eventually returning to the heart and beginning the process again.

Question 9

explain how the blood vessels change as blood flows in a circuit away from the heart and back to the heart

Answer 9

blood leaves the heart through large blood vessels(arteries) then branch off to smaller blood vessels(arterioles) and eventually branch off into extremely small vessels(capillaries). going back to the heart, the capillaries begin to grow in size and merge to (a little) larger blood vessels(venules) and eventually merge into large blood vessels(veins)

Question 10

how many layers are arteries/arterioles composed of

Answer 10

3

Question 11

what are the 3 layers that arteries/arterioles are composed of(specify which ones are the inner, middle, and outer layers)

Answer 11

endothelium cells - inner layer
smooth muscle tissue - middle layer
connective tissue - outer layer

Question 12

how do the arteries regulate/accommodate blood flow from the heart

Answer 12

by expanding and shrinking their diameter

Question 13

what is dilation(in terms of arteries)

Answer 13

when the arteries increase their diameter (decrease the blood pressure)

Question 14

what is constriction(in terms of arteries)

Answer 14

when the arteries decrease their diameter (increase blood pressure)

Question 15

what are capillaries composed of

Answer 15

a single layer of endothelium cells and a basement membrane

Question 16

what is a basement membrane

Answer 16

a specialized layer of membrane for support

Question 17

what does the composition of capillaries allow them to do

Answer 17

it allows them to move molecules between the blood and cells efficiently

Question 18

how are capillaries arranged and explain what it is

Answer 18

they are arranged in capillary beds, large assemblages of capillaries in a specific area

Question 19

how does the body close off capillary beds

Answer 19

by using shunts to bypass the capillary beds called anastomoses

Question 20

how do anastomoses work

Answer 20

using their sphincters, they can block off the associated capillaries to prevent any blood flow to the beds

Question 21

describe the structure of veins/venules

Answer 21

they have a similar 3-layer structure as arteries/arterioles, but with less smooth muscle and matrix

Question 22

what are the main differences between veins and arteries

Answer 22

the presence of valves within veins and how veins are more elastic than arteries

Question 23

what is the function of the valves in the veins

Answer 23

to prevent backflow of the blood

Question 24

what is the function of the increased elasticity of the veins

Answer 24

it allows them to expand and enlarge more and allows them to act as a reservoir(a supply) of blood for the rest of the body

Question 25

how can the continuous circuit(through which blood travels) be separated into sub-circuits

Answer 25

it can be grouped into 2 distinct subcircuits, the PULMONARY circuit and the SYSTEMIC circuit

Question 26

describe the pulmonary circuit

Answer 26

it begins at the right side of the heart where the blood is deoxygenated. the blood then travels to the lungs using the pulmonary arteries to become oxygenated in the lung’s capillary beds. the pulmonary circuit then ends when the blood returns to the left side of the heart using the pulmonary veins

Question 27

describe the systemic circuit

Answer 27

it begins at the left side of the heart when the oxygenated blood is pumped out of the aorta into the arteries, which become arterioles and eventually capillaries as the blood progresses through this circuit. nutrient and waste exchange is performed in those capillaries and then the deoxygenated blood(from those exchanges) travels from the capillaries into the venules which becomes veins(as the blood progresses) and then the deoxygenated blood arrives at the right side of the heart from the vena cava