Lecture 7: Capillaries and Lymphatics

Question 1

What is the function of Capillaries?

Answer 1

Site of exchange between blood and tissues

Question 2

What does the large total area of the capillary bed compared to arterioles mean?

Answer 2

Much slower blood flow

Question 3

What are 3 features of capillaries?

Answer 3

• Very thin walls
• Large total cross sectional area of capillary bed
• Slow & smooth blood flow

Question 4

What are erythrocytes?

Answer 4

Red blood cells

Question 5

Why are Capillaries only approximately 1 red blood cell in width?

Answer 5

Reduces the distance from the red blood cell to the surrounding tissue

Question 6

What type of intercellular junction fuses the Capillary cell shut?

Answer 6

Tight junctions

Question 7

What drains into Capillary beds?

Answer 7

Arterioles

Question 8

What drains from the Capillary beds?

Answer 8

Venules

Question 9

What is the role of the Precapillary sphincters?

Answer 9

Constrict to stop blood going into the Capillary beds

Question 10

What is the name of the pathway that allows blood from the arteriole to the venules without passing through the exchange surface?

Answer 10

The Vascular shunt

Question 11

Why is blood shunted away from the capillary beds?

Answer 11

To stop heat loss from blood and keep it away from the skin surface

Question 12

What are Precapillary sphincters composed of?

Answer 12

Smooth muscle cells

Question 13

What are the 3 types of Capillaries?

Answer 13

• Continuous
• Fenestrated
• Sinusoidal

Question 14

What components make up a Capillary?

3

Answer 14

• Basement membrane
• Endothelial layer
• Intercellular cleft

Question 15

What produces the Basement membrane?

Answer 15

The endothelial cell of the Capillary

Question 16

What do substances have to pass through from the Capillaries to go to the tissue?

Answer 16

Both the Endothelial cell and the basement membrane

Question 17

What is an intercellular cleft?

Answer 17

A channel between two cells through which molecules may travel

Question 18

What do vesicles in the Capillaries do?

Answer 18

They carry things that can’t move by passive diffusion

Question 19

Where are continuous Capillaries likely to be found?

Answer 19

Skeletal and Cardiac muscle

Question 20

What are the openings in fenestrated capillaries?

Answer 20

Small porous openings/physical openings

Question 21

What is the approximate size of Continious/Fenestrated capillaries?

Answer 21

8-10 microns in diameter

Question 22

Why is the lumen bigger in Sinusoidal Capillaries?

Answer 22

Trying to facilitate exchange with something other than gases

Question 23

What is an example of where Sinusoidal Capillaries are found?

Answer 23

Liver

Question 24

What happens to the basement membrane around sinusoidal capillaries?

Answer 24

It is disrupted and cannot be seen

Question 25

How is permeability controlled at intercellular clefts?

Answer 25

By the amount of tight junctions that are present there

Question 26

What are 4 ways of transport from Capillaries?

Answer 26

- Diffusion through membrane - Movement through intercellular clefts - Movement through fenestrations - Transport via vesicles

Question 27

What Type of substance move by diffusion through membranes?

Answer 27

Lipid-soluble substances

Question 28

What Type of substance move by movement through intercellular clefts/fenestrations?

Answer 28

Water soluble substances

Question 29

What Type of substance move by transport via vesicles?

Answer 29

Large substances

Question 30

What type of movement across the membrane occurs through Fenestrated/Sinusoidal Capillaries?

Answer 30

All types of movement

Question 31

What type of movement doesn't occur at Continuous Capillaries?

Answer 31

Movement through Fenestrations

Question 32

How is fluid shifted back to the heart that has left the blood vascular system?

Answer 32

Lymph Vascular system

Question 33

What is the role of lymph nodes in the lymph system?

Answer 33

Immune system surveillance

Question 34

What are the functions of the Lymph Vascular system? | 4

Answer 34

- Drain excess tissue fluid/plasma proteins and return to the blood - Filter foreign material from the lymph - 'Screens' lymph for foreign antigens and responds by releasing antibodies - Absorbs fat

Question 35

What are lacteals?

Answer 35

Special lymphatic cells that drain fat

Question 36

Where is fat from the gut drained too?

Answer 36

Cisterna chyli

Question 37

What is present all throughout the lymph vessels?

Answer 37

Valves

Question 38

What is particular about Lymph channel walls?

Answer 38

They are the thinnest walls of all vessels

Question 39

What are 3 features of lymph vessels?

Answer 39

- Thin walled - No Red blood cells - Possess valves

Question 40

What is the left side of the body any everything below the diaphragm drained through?

Answer 40

The Lymphatic collecting vessels

Question 41

What do the Lymphatic collecting vessels drain into?

Answer 41

The Thoracic duct

Question 42

What is the only type of fluid found at in the Thoracic duct?

Answer 42

Lymphatic fluid

Question 43

What does the Thoracic duct drain into?

Answer 43

The left Subclavian Vein

Question 44

What does the right side of the face/right upper limb and right side of the chest drain through?

Answer 44

Right lymphatic duct

Question 45

What does the right lymphatic duct drain through?

Answer 45

The right Subclavian vein

Question 46

What carries blood with nutrients from the intestines to the gut?

Answer 46

The Portal vein

Question 47

What is a Lacteal?

Answer 47

A special lymph capillary for draining fat

Question 48

Where are typical places for lymph nodes to be clustered? | 3

Answer 48

- Armpit - Groin - Neck

Question 49

What does lymph fluid pass into the lymph node through?

Answer 49

Afferent lymphatics

Question 50

What does lymph fluid pass out of the lymph node through?

Answer 50

Efferent lymphatics

Question 51

In order what is the drainage path of the right breast? | 4

Answer 51

- Lymphatic vessels of the breast - Axillary lymph node - Drained into the right lymphatic duct - Right Subclavian vein (Blood vascular system)