8.3 Blood, Tissue Fluid & Lymph

Question 1

Why does tissue fluid have a similar composition to blood?

Answer 1

Formed out of components of blood

which are forced out of the capillary along with plasma

due to hydrostatic pressure.

Question 2

What does the blood carry?

Answer 2

Glucose, Amino acids, Mineral ions, Hormones,
Plasma proteins, Red blood cells, White blood cells,
Platelets

Question 3

What 3 plasma proteins does the blood carry?

Answer 3

ALBUMIN - maintains ψ

FIBRINOGEN - involved in blood clotting

GLOBULINS - transport + immune system

Question 4

What is tissue fluid?

Answer 4

SOLUTION surrounding cells of multicellular animals

SAME COMPOSITION as blood but without RBCs + large plasma proteins

Question 5

What are gaps in the endothelium called?

Answer 5

fenestrations

Question 6

What are the functions of the blood?

Transport of…

Answer 6

O2 + CO2 to and from respiring cells

DIGESTED molecules from small intestine

NITROGENOUS WASTE ⟶ excretory organs

HORMONES: site of production ⟶ action

PLATELETS ⟶ damaged tissue

CELLS + ANTIBODIES

Question 7

What are the OTHER functions of the blood? (not transport)

Answer 7

maintains pH by acting as BUFFER

maintains TEMPERATURE (distributes heat using plasma)

Question 8

What happens at the ARTERIAL END of the capillaries?

Answer 8

hydrostatic pressure > oncotic pressure

so water/plasma moves out of vessel by OSMOSIS

carries SOLUTES from blood with it, which move by MASS FLOW out of FENESTRATIONS

less water now remains in blood vessel, so hydrostatic pressure ￬

Question 9

What happens after tissue fluid is formed?

Answer 9

BATHES cells

DIFFUSION between cells + tissue fluid

Question 10

What happens at the VENOUS END of the capillary?

Answer 10

oncotic pressure > hydrostatic pressure

so ≈ 90% tissue fluid REABSORBED into capillary by OSMOSIS

carries WASTE substances with it

Question 11

What is HYDROSTATIC PRESSURE?

Answer 11

pressure created by WATER in an ENCLOSED SYSTEM

always positive

Question 12

What is ONCOTIC PRESSURE?

Answer 12

tendency of H2O to move INTO BLOOD

by OSMOSIS

due to lower ψ created by plasma proteins

(approx -3.3kPa)

Question 13

What is the relative magnitude of forces in the arterial end?

Answer 13

hydrostatic pressure > oncotic pressure

in terms of magnitude

Question 14

What is the relative magnitude of forces in the venous end?

Answer 14

oncotic pressure > hydrostatic pressure

in terms of magnitude

Question 15

What is lymph?

Answer 15

MODIFIED tissue fluid

COLLECTED in the LYMPH system

(tissue fluid which is not reabsorbed after exchange with cells)

Question 16

How is lymph returned into the bloodstream?

Answer 16

remaining tissue fluid DRAINS into blind-ended LYMPHATIC CAPILLARIES

formation of LYMPH

moved along vessel by surrounding MUSCLE CONTRACTIONS + help from VALVES

LYMPHOCYTES build up at LYMPH NODES - produce ANTIBODIES

(during infection, lymphocytes multiply @ lymph nodes)

lymph reenters blood in left + right SUBCLAVIAN VEINS

Question 17

What is a blind-ended vessel?

Answer 17

a vessel which is open at one end and closed in the other

Question 18

What is the difference in composition of tissue fluid + lymph?

Answer 18

lymph contains LESS NUTRIENTS - since diffused into cell during exchange

lymph contains MORE FATTY ACIDS -

Question 19

Lymph capillaries converge to make larger vessels. How is this larger vessel similar to veins?

Answer 19

contains VALVES

fluid is moved through vessel by MUSCLE CONTRACTIONS

Question 20

What happens at the lymph nodes during an infection?

Answer 20

accumulated lymphocytes multiply

Question 21

How do lymph nodes protect the body from pathogens?

Answer 21

LYMPHOCYTES accumulate, multiply + produce more antibodies

which INTERCEPT bacteria in lymph, preventing them from reabsorbing into blood

Question 22

In what BLOOD vessel does the lymph drain into?

Answer 22

right/left subclavian veins

Question 23

What are the solutes found in blood but not in tissue fluid?

Answer 23

erythrocytes, large plasma proteins

Question 24

Why are red blood cells and large plasma proteins not found in tissue fluid?

Answer 24

TOO BIG to pass through FENESTRATIONS in endothelium

Question 25

Though red blood cells are not found in tissue fluid, ___ is.

Answer 25

oxygen

Question 26

approximately how much tissue fluid which is formed drains back into the blood?

Answer 26

90%

Question 27

What is the relative composition of components in the blood?

Answer 27

55% plasma

45% RBC, WBC, platelets,