Lymphatic system

Question 1

Why is the lymphatic system important?

Answer 1

Critical for maintaining constant blood volume

Question 2

What two pressure forces act on capillaries that causes them to lose fluid?

Answer 2

Hydrostatic pressure and colloid osmotic pressure

Question 3

What is hydrostatic pressure?

Answer 3

The force of a fluid pressing on the walls of the blood vessel

Question 4

What are the 2 fluids in and surrounding capillaries that exert hydrostatic pressure?

Answer 4

Blood plasma on the inside and the extracellular fluid on the outside

Question 5

What is the colloid osmotic pressure?

Answer 5

Fluids will flow from an area with high protein concentration to an area with low protein concentration

Question 6

Why is there a net fluid loss from capillaries?

Answer 6

There is a lower protein concentration in the extracellular fluid than in the blood plasma

Question 7

What does the Starling-Landis hypothesis describe?

Answer 7

Pressure differences along the capillary to model fluid exchange across capillary walls

Question 8

What happens to the capillary osmotic pressure through the vessel?

Answer 8

Stays constant. The losses and gains of fluids aren’t enough to change the osmotic pressure

Question 9

What happens to the hydrostatic pressure through the vessel?

Answer 9

Declines

Question 10

When does net filtration from the capillaries occur?

Answer 10

Right at the ends of the arteries to about the centre

Question 11

When does net reabsorption from the capillaries occur?

Answer 11

From the centre of the capillaries until the venules

Question 12

Why does net filtration and net reabsorption from capillaries occur?

Answer 12

Pressure differences between the osmotic pressure and the hydrostatic pressure

Question 13

What is the pressure difference between the osmotic and hydrostatic pressures in the capillary when net filtration is occurring?

Answer 13

Hydrostatic pressure is greater than the osmotic pressure

Question 14

What is the pressure difference between the osmotic and hydrostatic pressures in the capillary when net reabsorption is occurring?

Answer 14

Hydrostatic pressure is less than the osmotic pressure

Question 15

What is the problem with a closed circulatory system in the sense of maintaining blood volume?

Answer 15

The hydrostatic pressure gradient will always drive fluid out of the blood vessels and decrease the blood volume

Question 16

How does having a lymphatic system get around the fluid loss problem with a closed circulatory system?

Answer 16

System collects the fluid drawn out of the capillaries and sends it back to the heart

Question 17

Where does the lymphatic system drain into?

Answer 17

Into the inferior vena cava, which then empties into the right atrium

Question 18

What is the fluid that enters the lymphatic system called?

Answer 18

Lymph

Question 19

How does the lymphatic system maintain unidirectional flow?

Answer 19

Valves

Question 20

How can mast cells mess with the lymphatic system?

Answer 20

They release histamine in response to injury, which causes vasodilation and more fluid loss due to increased hydrostatic pressure. Causes swelling, blisters, inflammation

Question 21

What is elephantiasis?

Answer 21

Condition caused by parasitic filarial worms. Blocks the lymph nodes and causes a huge amount of swellling

Question 22

What is a pulmonary edema?

Answer 22

Fluid build-up in alveoli

Question 23

What causes a pulmonary edema?

Answer 23

Heart attack, congestive heart failure, trauma to lung, inhalation of noxious gases. Causes the left side of the heart to pump less than the right side

Question 24

What happens during a pulmonary edema?

Answer 24

Because the left heart isn’t pumping as much, blood gets backed up to the lungs, which increases the hydrostatic pressure and net filtration in the pulmonary capillaries. The increased pressure causes the fluid to go into the alveoli, which decreases gas exchange

Question 25

What are the symptoms of a pulmonary edema?

Answer 25

Difficulty breathing, coughing blood, pale skin

Question 26

Where are mechanoreceptors found in the heart? What do they monitor?

Answer 26

Atrial walls: monitor filling and contraction

Ventricular walls: monitor stretching in response to the diastolic blood volume

Question 27

Where are chemoreceptors found? What do they monitor?

Answer 27

Found in arteries and respond to changes in blood CO2 or H+ concentrations