Blood And Lymphatic Vessels

Front 1

Tunica intima

Back 1

- endothelium
- basal lamina
- thin CT (barely visible in healthy tissue)
- internal elastic lamina (medium and large arteries)

Front 2

tunica media

Back 2

- collagen (very fine, not visible)
- smooth muscle
- dispersed elastic sheets called elastic lamallae
- visible external elastic lamina (large arteries)

Front 3

tunica adventitia

Back 3

- loose CT
- collagen
- reticular fibers
- small blood vessels and peripheral nerves

Front 4

vaso vasorum

Back 4

- bring nutrients, O2, blood to tunica media
- located in tunica adventitia

Front 5

aorta

Back 5

- an elastic artery
- tunica media: thick (~ 40 layers)
--> contains many elastic lamellae
- need good amount of CT to withstand high velocity and pressure
- elastic lamellae absorbs energy during systole, delivers it back during diastole

Front 6

large arteries

Back 6

- tunica media contains fenestrated elastic sheets interspersed with smc's
- elastic lamellae store potential energy
- examples: aorta, pulmonary trunk

Front 7

medium (muscular) arteries

Back 7

- tunica media contains several layers of smc's
- visible internal elastic lamina
- example: femoral, brachial, ulnar, and renal arteries

Front 8

arterioles

Back 8

- tunica media contains few layers of smooth muscle
- non visible internal elastic lamina
- smallest arterioles deliver blood to the capillary bed
- adventitia blends with surrounding CT

Front 9

capillaries

Back 9

- very thin walled tubes composed of endothelium and underlying basal lamina
- exchange of nutrients, waste products, and gases between blood and tissues

Front 10

continuous capillary

Back 10

- no fenestrae
- tight junctions
- exchange across endothelium via transcytosis
- locations: CNS, lungs, muscles, and CT

Front 11

fenestrated capillary

Back 11

- fenestrae allow faster exchange
- examples: choroid plexus of brain, gall bladder, intestines, and endocrine glands

Front 12

sinusoidal capillary (sinusoid)

Back 12

- lumen is very large in diameter which slows blood flow
- large fenestrae allow blood plasma unimpeded access to tissue

Front 13

venules

Back 13

- large diameter endothelial tubes with little smooth muscle
- post capillary venules --> primary location for white blood cells to leave blood and enter tissues

Front 14

medium veins

Back 14

- tunica media contains smooth muscle
- tunica media is thinner than adventitia

Front 15

large veins

Back 15

- tunica media has more smooth muscle than a medium vein but less than a comparable artery

Front 16

tunica intima under healthy conditions

Back 16

endothelial cells:
- no clot formation or sticking of blood cells to walls
- tight juntions --> minimize cell and fluid loss
- transport select materials

Front 17

tunica intima in times of injury or disease

Back 17

- promote clots
- loose junctions allow movement from blood to tissue
- leukocyte attachment for exit into tissue
- lipid and smooth muscle cell accumulation to close up vessel

Front 18

pericytes

Back 18

- wrap around outside of blood vessel
- small arterioles, capillaries, and venues
- sphincters that contract to regulate blood flow in capillaries

Front 19

functions of pericytes

Back 19

1. wound healing and vessel growth
- stem cells that differentiate into smooth muscle
2. similar to smooth muscle cells
-pre capillary arteries regulate blood flow to capillary beds

Front 20

function of lymphatic vessels

Back 20

1. collect extracellular fluid and white blood cells from CT spaces
2. filter through lymph nodes
3. return to blood

Front 21

structure of lymphatic vessels

Back 21

- similar to veins
- thinner walls (low pressure)
- very permeable
- no tight junctions
- contain valves
- blind-ended tubes
- discontinuous basal lamina

Front 22

defects in lymphatic vessels

Back 22

failure of lymphatic vessels result in accumulation of fluid in tissues --> edema

Front 23

arteriovenous anastomoses

Back 23

shunt pathways that can regulate the flow of blood into capillary beds