exam 4 blood & blood vessels Flashcards
What are blood vessels?
pipelines for the blood; includes arteries, veins, & capillaries
What are arteries?
vessels that carry blood AWAY from the heart & into an organ, tissue, or body region
What are the types of arteries?
elastic, distributing, arterioles, & metarterioles
What are elastic arteries?
they expand & contract as ventricles contract & relax; includes great vessels (aorta & PAT)
What are distributing arteries?
travel into specific body regions; includes brachial, femoral, renal, etc.
What are arterioles?
branch from distributing arteries; have smooth muscle in their walls that regulates the amount of blood that passes from them; they can vasoconstrict/vasodilate
What are metarterioles?
branch from most arterioles that lead into capillaries; they can vasoconstrict/vasodilate
What are the 3 layers in the walls of all arteries?
endothelium, muscularis, & serosa (deep to superficial)
What is the endothelium?
slick type of epithelium that lines inside arteries
What is the muscularis?
layer of smooth muscle in walls of arteries; thick in the elastic arteries & thins out with each branch
What are the nervi-vasorum?
nerves in the ANS that control contraction/relaxation of the muscularis layer
What are the vaso-vasorum?
tiny blood vessels that give the muscularis its own blood supply in the elastic arteries & large distributing arteries
What is the serosa?
outer covering of arteries that binds many veins & arteries together in one unit; often binds nearby nerves as well
What are capillaries?
small vessels that may be microscopic; they allow blood to perfuse tissues
What is perfusion pressure?
the amount of force required to provide blood to a specific body part via capillaries
What controls perfusion pressure?
cardiac output, vasodilation, & vasoconstriction of arterioles & metarterioles
What are the 3 types of capillaries?
continuous, fenestrated, & sinusoidal
What are continuous capillaries?
the endothelium has cells close together with tiny holes in between that only allow water, ions, salts, & sugars to “leak” through; can be found in skeletal muscle
What are fenestrated capillaries?
the endothelium has medium-sized holes between cells; good for absorption, secretion, & filtration; can be found in glomerulus
What are sinusoidal capillaries?
the endothelium has large holes between cells making blood cells able to pass into or out of; can be found in red bone marrow
What are veins?
vessels that RETURN blood to the heart from organs, tissues, or body regions
What are the 2 types of veins?
venules & veins
What are venules?
mergers of capillaries
Why can’t veins expand or contract much?
they lack abundant smooth muscle & it is sometimes arranged in spiral fashion which also makes their walls thin
Why is it important for most veins’ endothelial lining to be folded into ridges?
some of these ridges form valve-like structures which help the blood return to the heart by preventing backflow
Why is it beneficial for veins to be located deep to skeletal muscle?
as the muscle contracts, the vein is “massaged” to help move blood back to the heart
What are varicose veins?
when blood backflows & the vessel stretches
What could cause varicose veins?
being female (smaller muscle mass), sitting or standing a lot, pregnancy, age, & cardiovascular health issues
What is blood?
a type of connective tissue with “cells” called formed elements scattered in liquid matrix called plasma
What are the functions of blood?
transports O2, CO2, ions, hormones, sugars, & cellular waste, regulates pH of interstitial fluids (ICF), defends against invading pathogens, controls body temperature, & protects from its own loss by forming clots
What is plasma made of?
water (most abundant component of blood making up about 92% of plasma), dissolved solutes (ions, sugars, salts), & plasma proteins
What are the 3 types of plasma proteins?
albumin, globulin, & fibrinogen
What is albumin?
produced by the liver; provides osmotic pressure that pulls excess water from ICF to prevent swelling
What is globulin?
large 3-D proteins that transport large molecules such as steroids & steroid hormones (mostly end in “-one”)
What are immunoglobulins?
specialized globulins which are antibodies that protect us against infection/disease
What is fibrinogen?
an inactive form of fibrin which is used for clot formation; conversion of fibrinogen to fibrin occurs when fibrinogen is exposed to charged molecules
What are formed elements?
cells & cell fragments that develop from hematopoietic stem cells in spongy (red) bone marrow
What do the hematopoietic stem cells form?
1 of 2 cell lines; these include lymphoid & myeloid cell lines
What is the lymphoid cell line?
cells that develop in red bone marrow; some circulate in blood, others reside in bone marrow, & additional ones migrate to lymph nodes, organs (tonsils), or lymph vessels
What 2 cells develop from the lymphoid cell line?
lymphocytes & monocytes
What are lymphocytes?
protects from specific toxins & antigens
What are monocytes?
can exit blood vessels & wander through infected tissue; they become macrophages which engulf & destroy pathogens/debris
What is the myeloid cell line?
it differentiates into basophils, eosinophils, neutrophils, megakaryocytes, & erythrocytes
What are basophils?
produce histamine which promotes inflammation
What are eosinophils?
abundant in allergies
What are neutrophils?
engulf & destroy pathogens/debris
What are megakaryocytes?
big cells that fragment into pieces called platelets which are very small, have no nucleus & minimal organelles, so they only live 5-7 days
What happens when platelets get sticky & how do they become sticky?
they become sticky when exposed to air or connective tissue & they stick together, forming clots which triggers more platelets to stick together, causing the clot to increase in size
What are erythrocytes?
red blood cells; biconcave disk shaped cells (this shape is perfect for hemoglobin to fit inside) with no nucleus once mature
Why do erythrocytes only have no nucleus once they are mature?
they lose their nucleus when they enter blood vessels from red bone marrow to have more space in the cell
What is erythropoietin?
a hormone from the kidneys that controls the manufacture of erythrocytes
How do new erythrocytes enter circulation?
through sinusoidal capillaries
Why do erythrocytes lack mitochondria?
so that the oxygen they carry is not used up by mitochondria
What is hemoglobin made of?
globin (a protein) & heme (a red iron containing pigment)
RBC circulate for about 3 months, what happens after this period?
old RBC travel to liver & spleen where they’re broken down & heme is stripped of its iron & is recycled
What is bilirubin?
it becomes part of the feces as it is removed from the body; the iron from heme & other components are incorporated into it
