8.3 Blood, tissue fluid and lymph

Question 1

Blood percentages: what makes up most of the blood?

Answer 1

Plasma (55%) - much of this is water.

Question 2

Blood percentages: what makes up the rest of the blood after plasma (55%)

Answer 2

Erythrocytes, platelets, leukocytes (45%)

Question 3

What is the yellow liquid that blood mainly consists of and what is its function?

Answer 3

Plasma;
- carries a wide variety of components including:
= dissolved glucose, amino acids, mineral ions, hormones, large plasma proteins (i.e. albumin), fibrinogen and globulin

Question 4

What are platelets?

Answer 4

Fragments of large cells called megakaryocutes found in the red bone marrow - involved in the clotting mechanism of the blood.

Question 5

Fill in the blank: Only the plasma and the ___ _____ _____ are involved in the transport functions of the blood.

Answer 5

Red blood cells

Question 6

Fill in the blanks: The composition of the _____ is closely related to its functions in the ____, many of which involve transport.

Answer 6

a) Blood

b) Body

Question 7

What does the blood transport? (8 answers)

Answer 7

• oxygen to respiring cells
• carbon dioxide away from respiring ells
• digested food from small intestine
• nitrogenous waste products from cells to excretory organs
• hormones (chemical messages)
• food molecules from storage molecules to cells
• platelets to damaged areas
• cells and antibodies involved in the immune response

Question 8

What are the gaps in the capillary walls called?

Answer 8

Fenestrations

Question 9

Fill in the blanks: Substances dissolved in the ______ can pass through the fenestrations in the _________ walls, with the exception of large plasma proteins.

Answer 9

a) Plasma

b) Capillary

Question 10

Do plasma proteins have an osmotic effect? (Name a specific example)

Answer 10

Yes - specifically albumen

Question 11

What 2 potential properties do plasma proteins give blood in the capillaries compared to the surrounding fluid?

Answer 11

• Relatively high solute potential

- Relatively low water potential

Question 12

Fill in the blanks: Water has a tendency to move into the _____ in the ___________ from the surrounding fluid by _______.

Answer 12

a) Blood
b) Capillaries
c) Osmosis

Question 13

What is the tendency of water to move into the blood by osmosis referred to as?

Answer 13

Oncotic pressure - usually this is around -3.3kPa

Question 14

What is hydrostatic pressure?

Answer 14

Where blood flowing through the capillaries is still under pressure from the surge of blood that occurs every time the heart contracts.

Question 15

What is the hydrostatic pressure at the arterial end of an arteriole?

Answer 15

4.6kPa - relatively high

Question 16

Is the hydrostatic pressure at the arterial end of an arteriole higher than the oncotic pressure (which attracts water in by osmosis)? (Yes/No)

Answer 16

Yes - fluid is squeezed out of the capillaries as a result

Question 17

Fill in the blank: Tissue fluid has the same composition as ______, without the red blood cells and the plasma proteins.

Answer 17

Plasma

Question 18

What happens to the balance of forces when blood moves through the capillaries towards the venous system?

Answer 18

It changes

Question 19

How does the hydrostatic pressure in the venous system drop to 2.3kPa as blood moves through the capillaries towards it?

Answer 19

Fluid moves out, so the pulse is completely lost

Question 20

As the hydrostatic pressure drops due to tissue fluid moving out of the system, what happens with the oncotic pressure?

Answer 20

It becomes stronger than the hydrostatic pressure, so water moves back into the capillaries via osmosis as it approaches the venous end of the capillaries.

Question 21

By the time blood returns to the veins, what percentage of tissue fluid is back in the blood vessels?

Answer 21

90%

Question 22

What is lymph?

Answer 22

The 10% of tissue fluid that does not return to the blood - it instead drains into blind-ended tubes called lymph capillaries.

Question 23

What are the differences between lymph as compared with plasma or tissue fluid?

Answer 23

Less oxygen, fewer nutrients, contains fatty acids absorbed from the villi of the small intestine

Question 24

Fill in the blanks: The lymph ___________ join up to form larger vessels. The fluid is transported through them by the squeezing of the body _______.

Answer 24

a) Capillaries

b) Muscles

Question 25

What similarity can be drawn between veins and lymph capillaries?

Answer 25

They both have valves to prevent backflow

Question 26

Where does the lymph eventually return to the blood?

Answer 26

The right or left subclavian veins (under the clavicle, a.k.a. the collar bone)

Question 27

What are found alongside lymph vessels?

Answer 27

Lymph nodes

Question 28

What do lymph nodes contain?

Answer 28

Lymphocytes

Question 29

What do lymphocytes do?

Answer 29

Build up in the lymph nodes where necessary and produce antibodies which are then passed into the blood

Question 30

Do lymph nodes intercept bacteria and other debris from the lymph? (Yes/No)

Answer 30

Yes - the debris or bacteria is then ingested by phagocytes also found in the nodes

Question 31

What major role does the lymphatic system play with regards to the body?

Answer 31

It plays a major role in the defence mechanisms of the body

Question 32

What are enlarged lymph nodes a sign of?

Answer 32

The body fighting off an invading pathogen, which is why doctors often examine the neck, armpits, stomach or groin of their patients, which are the sites of some major lymph nodes/glands.