Transport (Blood and Lymph) Flashcards
Functions of blood
- transports O2, CO2, nutrients, waste, hormones, and enzymes
- protects the body with leukocytes and clotting
- regulates body systems (pH, electrolytes, body temperature)
hematopoiesis
- the formation of blood
- formed in the liver and spleen before birth
- the red bone marrow produces blood cells after 5 months of age and primary sit of them after birth
what are the components of blood
- plasma
- formed elements (Buffy coat and erythrocytes)
plasma
- a sticky, yellow, fluid
- this is the fluid portion of the blood
- the components can change quickly and frequently and it reflects metabolic activity
- this can be an important diagnostic tool
why can plasma be donated more often than whole blood
plasma is mostly water so it is easier to replace what has been lost through the donation by hydrating and eating food to make up for the lost proteins
-it is much harder to replace formed elements of the blood that are lost with blood donation
platelets
- also called thrombocytes
- these are the smallest circulating formed elements
- they are cell fragments
- they have a lifespan of about 8 days
- these clump at sites of injury and make a plug there and then release chemicals to attract fibrin and other cells
erythrocytes
- red blood cells
- no nucleus or organelles (not true cells)
- has hemoglobin
- has a 120 day lifespan
- has a biconcave shape
leukocytes
- white blood cells
- these are for defense
- a short lifespan of a few days
- they can function outside of the blood stream in connective tissue as well.
- two main types
what are the two classifications of white blood cells
- granulocytes and agranulocytes
neutrophil
- a granulocyte
- this is the most common type of white blood cell
- this is used to kill bacteria
- levels are elevated when there is a bacterial infection
eosinophil
- this is a granulocyte
- only 2-4% of the white blood cells
- this is elevated when there is a parasite (some for allergic reactions)
basophils
- this is a granulocyte
- only <1% of the white blood cells
- these are in high concentration when there is allergic reactions (and also parasites)
monocyte
- this is a type of agranulocyte
- only 2-8% of the white blood cells
- these are responsible for a non specific immune response
- they find foreign things in the body and act as a phagocyte to get rid of them
lymphocyte
- this is a type of agranulocyte
- 20-30% of the white blood cells
- this is responsible for specific immunity (t cells/b cells/NK cells)
- this gets elevated in an immune response
tunica adventitia
- thick layer composed of collagen fibers with scattered bands of elastic fibers
- the fibers blend into those of adjacent tissues to anchor and stabilize the blood vessel
- the outer most layer of the wall of blood vessels
tunica media
- the middle layer of the wall of blood vessels
- concentric layers of smooth muscles around the lumen of the vessel
- these are what allow contraction and dilation of vessels
- collagen fibers bind this layer to the two other layers of blood vessels
tunica intima
- the inner most layer of the wall of blood vessels
- composed of endothelial lining of the vessel and an underlying layer of connective tissue with elastic fibers
vasa vasorum
these are blood vessels that supply the walls of large arteries and veins
what are the layers of the walls of blood vessels
- tunica adventitia
- tunica media
- tunica intima
describe artery walls compared to the walls of veins
- arteries have thicker walls
- more smooth muscle and elastic fibers (need to be able to resist the pressure from the heart as blood is forced into circualtion
describe the difference between the lumens of arteries and veins
- veins have larger lumens
- in dissection, veins will look more distorted and flat
- in dissection, arteries will maintain their circular shape more
what is something important to remember that veins have that arteries do not
valves!
important because these are necessary for the blood to make it back to the heart from the periphery because of the low blood pressure in them
describe the difference between the vessel lining of arteries and veins
- arteries have an endothelial lining that appears pleated because when the vessel constricts it folds up because it cannot contract
- veins do not have a pleated appearance
elastic arteries
- large vessels that have a large lumen
- these have a thick intima
- these move large volumes of blood away from the heart
- has an internal elastic membrane between the media and intima to allow for stretch
- *very resilient walls with high elastic fibers and low smooth muscles
ex. aorta, pulmonary artery
muscular artery
- these are vessels that transport blood to the skeletal muscle and internal organs
- media is thick and has a lot of smooth muscle
- majority of arteries are this type.
arterioles
these are used to control blood flow between arteries and capillaries
- considerably smaller than arteries
- thin adventitia
- media is only one or two layers of smooth muscle
capillaries
- smallest and most delicate
- only vessels that walls allow for exchange of nutrients and wastes
- blood flow through these is slow to allow for adequate diffusion time
continuous capillaries
- found in all tissues but epithelia and cartilage (most common type)
- epithelium forms a complete lining and and the cells are connected by tight junctions and desmosomes
fenestrated capillaries
- these are made of simple squamous epithelial cells but also have pores in them
- allow for more exchange of nutrients (allow some small proteins and peptides)
sinusoids
these are discontinuous capillaries
- made of simple squamous epithelial cells that have large gaping holes in them (allow large things like blood cells through)
- the basil lamina is thinner
- these are common in the spleen
precapillary sphincters
- these regulate blood flow to tissues
- can open of close to regulate blood flowing through the area (allows or bipass if necessary)
thoroughfare channel
- these connect arterioles with postcapillary venules in the capilary bed
- this allows for the blood to be distributed someplace else when the precapillary sphincters are closed
- this runs through the capilary bed and occurs after the meta arteriole