module 3 - 8.3 blood, tissue fluid and lymph

Question 1

what is blood?

Answer 1

specialised transport medium that is also a connective liquid tissue

Question 2

what are the functions of blood?

Answer 2

• transport
• defence (immune system)
• thermoregulation
• maintaining pH of bodily fluids

Question 3

what are erythrocytes?

Answer 3

red blood cells

Question 4

what are platelets?

Answer 4

fragments of large megakaryocytes found in bone marrow, also involved in blood clotting

Question 5

what are leucocytes?

Answer 5

white blood cells (e.g. lymphocytes and phagocytes)

Question 6

what is unusual about human red blood cells?

Answer 6

they have no nucleus, they are packed with mRNA and ribosomes to make proteins

Question 7

what are the adaptations of human red blood cells?

Answer 7

flattened biconcave disc shape - large SA:V for efficient gas exchange
large amount of haemoglobin - for transporting oxygen
no nucleus or organelles - maximises space for Hb so more oxygen is transported

Question 8

what does 8% of blood plasma consist of?

Answer 8

plasma proteins (half are a group of proteins called ALBUMINS)

Question 9

what are albumins?

Answer 9

water soluble transport proteins that carry molecules and ions in the blood

Question 10

what is the function of albumins?

Answer 10

regulates osmotic pressure of blood (done by proteins so is called oncotic pressure - albumins displace water molecules)

Question 11

how do albumins cause dipoles?

Answer 11

they have a hydrophilic R group which means they can then hydrogen bond with water

Question 12

the typical human blood oncotic pressure is negative, what does this create?

Answer 12

a tendency for water to move into the blood from surrounding tissue by osmosis

Question 13

what is the blood pressure developed by the contraction of the heart?

Answer 13

high

Question 14

what is the pressure developed by the contraction of the heart called?

Answer 14

hydrostatic pressure

Question 15

what happens at the arteriole end of the capillary bed when hydrostatic pressure has fallen to +4.6kPa?

Answer 15

fluid is forced out the capillaries by the higher pressure in the blood, creates TISSUE FLUID

Question 16

what happens at the venule end of the capillary bed?

Answer 16

oncotic pressure is higher and acts in opposite direction so water moves back into capillaries

Question 17

is there a change in oncotic pressure at anytime?

Answer 17

no it stays the same all the time

Question 18

how is tissue fluid similar to blood plasma?

Answer 18

its the same but just without red blood cells and plasma proteins

Question 19

how does water go back into the blood?

Answer 19

by osmosis, otherwise blood would dry out

Question 20

what is the pressure difference between arterial and venous end of capillaries?

Answer 20

venous end has lower hydrostatic pressure than arterial end, due to friction

Question 21

what is the lymphatic system?

Answer 21

secondary circulatory system and major part of the immune system, complementary to cardiovascular system

Question 22

what are lymphatic capillaries?

Answer 22

vein-like lymph vessels containing valves

Question 23

what are lymph nodes?

Answer 23

sac-like organs that trap pathogens/ foreign substances that contain large number of white blood cells

Question 24

what is lymphatic tissue?

Answer 24

found in the spleen, thymus and tonsils - contains large amounts of white blood cells and is involved in their development

Question 25

what happens to the 10% of tissue fluid that is not returned to the blood?

Answer 25

flows into blind-ended lymph capillaries forming lymph

Question 26

what is lymph?

Answer 26

similar to plasma and tissue fluid but has less oxygen and nutrients and more fatty acids

Question 27

how is lymphatic fluid moved?

Answer 27

by body movements squeezing on lymph capillaries and vessels aided by one-way valves

Question 28

what does the flow of lymph along the thoracic duct cause?

Answer 28

a large lymph vessel to drain the subclavicle vein

Question 29

what is oedema?

Answer 29

build up of tissue fluid (caused by problems within the lymphatic system)

Question 30

what do phagocytes and lymphocytes do?

Answer 30

filter out bacteria using phagocytes in the lymph nodes