Human Phys 4.5 Flashcards

1
Q

What is the lymphatic system?

A

Accessory route for fluid and protein to flow from interstitial spaces to the blood

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2
Q

What is the lymphatic system important in preventing?

A

Edema

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3
Q

What is lymph derived from?

A

Interstitial fluid that flows into the lymphatics

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4
Q

What is the lymphatic system a major route for?

A

Absorption of nutrients form the GI tract

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5
Q

What does the lymphatic system play an important role in?

A

Immune system

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6
Q

What does fluid that does not re enter the capillary at the venous end do?

A

It is returned to the systemic circulation via lymphatics (about 1/10)

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7
Q

What is the total daily lymph flow?

A

2-3 L

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8
Q

What are endothelial cells anchored to?

A

Surrounded connective tissue via anchoring filaments

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9
Q

What do the endothelial cells overlap to create?

A

Valve like structures

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10
Q

What happens to lymph flow at low pressure?

A

It is reduced

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11
Q

What is lymph flows relationship to pressure?

A

They both increase together

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12
Q

Why does lymph flow plateau at 2 mmHg?

A

Due to excess pressure compressing the outside surfaces of the larger lymphatics

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13
Q

What does the compression force in lymph flow balance?

A

Increasing entry of fluid

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14
Q

What happens during the expansion phase in lymph flow?

A

Hydrostatic pressure in the interstitium exceeds that inside the initial lymphatic causing microvalves to open and fluid to enter

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15
Q

What happens during the compression phase of lymph flow?

A

Hydrostatic pressure inside the initial lymphatic rises, closing the microvalves and opening the secondary lymph valves, causing fluid to flow downstream

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16
Q

What happens when lymph vessels become stretched?

A

Smooth muscle cells contract

17
Q

What do valves prevent in lymphatics?

A

Backward flow

18
Q

How much pressure can be generated in large lymph vessels?

A

50-100 mmHg

19
Q

What do the external pumps do in lymph flow?

A

Contraction of surrounding muscles

Movements of body parts

Arterial pulsations adjacent to lymphatics

Compression of tissues by objects outside the body

20
Q

How much can lymph flow increase during exercise?

A

10-30 fold

21
Q

What are the key roles of the lymphatic system?

A

Controls concentration of proteins in the interstitial fluid

Controls volume of interstitial fluid

Controls interstitial fluid pressure