Exchange & the lymphatic system

Question 1

what is the starling equation

Answer 1

it is an equation that illustrates the role of hydrostatic and oncotic forces in the movement of fluid across capillary membranes

Question 2

what are the 3 processes that capillary movement may occur

Answer 2

diffusion
filtration
pinocytosis

Question 3

describe the lymphatic system

Answer 3

the network of vessel through which lymph drain from the tissues into the blood

Question 4

describe the blood brain barrier

Answer 4

a semipermeable membrane separating the blood from the cerebrospinal fluid, and constituting a barrier to the passage of cells, particle and large molecules

Question 5

what is the blood brain barrier

Answer 5

it is a highly selective semi-permeable membrane barrier

Question 6

what does the blood brain barrier separate

Answer 6

the circulating blood from the brain and extracellular fluid in the central nervous system

Question 7

describe 3 important functions of the blood brain barrier

Answer 7

• protect the brain from foreign substances in the blood that may injure the brain
• protect the brain from hormones and neurotransmitters in the rest of the body
• maintains a constant environment for the brain

Question 8

what is the role of capillaries

Answer 8

to carry blood to tissue cells and capillaries are the exchange site of nutrients, gases, wastes etc.

Question 9

what is the goal of coagulation

Answer 9

fibrin formation

Question 10

what does activation of the coagulation cascade lead to

Answer 10

the production of thrombin

Question 11

what does thrombin then convert

Answer 11

fibrinogen to fibrin

Question 12

what do physiological anticoagulation mechanisms act to reduce

Answer 12

thrombin production or to reduce the effects of thrombin

Question 13

what are collateral arteries

Answer 13

they are the arteries that come after coronary arteries

Question 14

what makes up the arteriole wall

Answer 14

smooth muscle

Question 15

where does the greatest change in blood pressure and velocity of blood flow occur

Answer 15

at the transition of arterioles to capillaries

Question 16

what are metarterioles

Answer 16

they are short vessels that link arterioles and capillaries

Question 17

what do metarterioles have instead of continuous tunica media

Answer 17

they have individual smooth muscle cells

Question 18

what does each individual smooth muscle cell in metarterioles form

Answer 18

a pre-capillary sphincter that encircles the entrance to that capillary bed

Question 19

what is the arteriovenous bypass also called

Answer 19

the arteriovenous shunt

Question 20

what is the arteriovenous bypass

Answer 20

the passage of blood directly from arteries to veins, without going through the capillary network

Question 21

what are pre-capillary sphincters

Answer 21

they are bands of smooth muscle that adjust blood flow into capillaries mainly in the mesenteric microcirculation

Question 22

where does a smooth muscle fibre encircle the capillary

Answer 22

at the point where each of the capillaries originates from an arteriole

Question 23

what is a venule

Answer 23

a very small vein, especially one collecting blood from the capillaries

Question 24

describe the gross structure of capillaries

Answer 24

they are specialised for blood exchange, there are lots of them, they are thin walled and have a small diametere

Question 25

what is meant by the ultrastructure

Answer 25

it is the fine structure, especially within a cell, can be seen only with high magnification obtainable with an electron microscope

Question 26

what does clotting involve

Answer 26

formation of a platelet lug and a fibrin clot

Question 27

what is carrier mediated osmosis

Answer 27

it is the movement of molecules across the cell membrane via special transport proteins that are embedded within the cellular membrane

Question 28

describe the diffusion of oxygen from the alveoli

Answer 28

oxygen diffuses from the alveoli into the blood in the capillaries

Question 29

describe the diffusion of carbon dioxide from the blood

Answer 29

carbon dioxide from the blood moves out of the capillaries into the alveoli

Question 30

describe the diffusion in general of oxygen and carbon dioxide

Answer 30

oxygen and carbon dioxide more from where there is a large concentration to where there is a lower concentration

Question 31

describe bulk flow

Answer 31

it is the movement of water and solutes together due to a pressure gradient

Question 32

what is hydrostatic pressure

Answer 32

it is the pressure exerted by a fluid at equilibrium at a given point within the fluid, due to the force of gravity

Question 33

hydrostatic pressure increases in proportion to depth measured from the surface because...

Answer 33

of the increasing weight of fluid exerting downward force from above

Question 34

what is oncotic pressure

Answer 34

it is a form of osmotic pressure exerted by proteins, notably albumin, in a blood vessel's plasma that usually tends to pull water into the circulatory system

Question 35

what is oncotic pressure the opposing force to

Answer 35

hydrostatic pressure

Question 36

describe the lymphatic system

Answer 36

the network of vessels through which lymph drains from the tissues into the blood

Question 37

describe lymph capillaries

Answer 37

tiny thin walled vessels located in the spaces between cells which serve to drain and process extra-cellular fluid

Question 38

what is a lymph node

Answer 38

it is a small swelling in the lymphatic system where lymph is filtered and lymphocytes are formed

Question 39

what are lymphatic vessels

Answer 39

they are thin walled vessels structured like blood vessels, that carry lymph

Question 40

what are lymphatic vessels complementary to

Answer 40

the cardiovascular system

Question 41

where do lymphatic vessels drain lymph to

Answer 41

into the right and left subclavian veins respectively

Question 42

what are lymph valves

Answer 42

any one of the tiny semilunar structures in the vessels and trunks of the lymphatic system

Question 43

what is the role of lymph valves

Answer 43

they help to regulate the flow of lymph and prevent venous blood from entering the systemic blood capillaries

Question 44

basically describe lymph valves

Answer 44

these are one-way valves that prevent backward flow of lymph in lymph vessels

Question 45

what is oedema

Answer 45

it is a condition characterised by an excess of watery fluid collecting in the cavities or tissues of the body

Question 46

what are signs of oedema

Answer 46

swelling or puffiness of the tissue directly under your skin especially in your legs or arms stitched or thing skin skin that retain a dimple, after being pressed for several seconds increased abdominal size

Question 47

what intact blood vessels central to

Answer 47

moderating blood's tendency to form clots

Question 48

what do the endothelial cells of intact vessels prevent

Answer 48

blood clotting with a heparin-like molecule and thrombomodulin and prevent platelet aggregation with nitric oxide and prostacyclin

Question 49

what are the functions of the lymphatic system

Answer 49

removal of interstitial fluid from tissues absorbing and transporting fatty acids and fats as chyle from the digestive system transporting white blood cells to and from the lymph nodes into bones

Question 50

what are causes of oedema

Answer 50

often a symptom of an underlying health condition

Question 51

list conditions and treatments that oedema can occur as a result of

Answer 51

``` pregnancy kidney disease heart failure chronic lung disease liver disease malnutrition medication - corticosteroids, medicine for hypertension the contraceptive pill immobility standing for long periods blood clots severe varicose veins leg injury leg surgery burns to the skin ```