Blood Vessel Structure and Blood

Name two more major difference between arteries and veins.

1. The walls of some arteries are too thick for oxygen and nutrients to go directly to their outer layers from the blood in their lumens, so walls of arteries have their own blood supply (capillaries) called vasa vasorum ("vessels of vessels") 2. It is more difficult to distinguish layers in veins; lumens of veins are generally much larger and the walls are thinner than arteries of equal size

Name 3 major differences between arteries and veins.

1. an artery's walls are thicker and the layers are more easily discernible 2. an artery's walls contain a tunica media with more smooth muscle and more elastin than veins 3. In the absence of pressure, while the lumen of an artery shrinks, it maintains its basic round shape unlike most veins.

List the types of capillaries.

1. continuous 2. fenestrated 3. sinusoids 4. low-permeability

What are the four ways molecules and proteins cross capillaries?

1. diffusion across cell membrane 2. diffusion through intercellular gaps 3. diffusion through pores 4. vesicular transport

What are the functions of platelets?

1. transport of clotting proteins 2. formation of temporary patches in walls of damaged vessels 3. actively contracting after clot formation to pull cut edges of vessel together

List four of the major functions of blood.

1. transport oxygen and carbon dioxide 2. distribute nutrients 3. transportation of waste 4. delivery of enzymes and hormones

List four other major functions of the blood.

1.stablization of pH (buffers) and electrolyte concentrations in interstitial fluids 2. prevention of fluid loss-clotting reaction seals leaks 3. defense 4. regulation of body temperature

plasma

55% of whole blood volume; straw like in color

water

92%; dissolves and transports molecules

List the basic blood types.

A, B, AB, O

Which blood type is the universal recipient?

AB

Which blood types are cross compatible?

AB, O

Which blood type is the universal donor?

O

What are the main components of blood?

RBCs, WBCs, platelets, and plasma

globulins

Transport proteins for small ions, iron, hormones, and lipids that may normally be insoluble or removed by kidneys

hematocrit

a value indicating the percentage of whole blood occupied by formed element

immunoglobulins

antibodies

Which type of artery is the smallest and largest?

arterioles=smallest; muscular arteries=largest

aneurysms

bulge in weakened wall of blood vessel usually in an artery; usually caused by chronic blood pressure, but can also form from any trauma, infection, and some genetic diseases; vessel may rupture and most dangerous ones are large arteries and arteries going to the brain

Rh factor

can have it or not; usually referred to as being Rh-negative if you do not have it or being Rh-positive if you do

leukemia

cancer from uncontrolled proliferation of leukocyte-forming cells

What blood vessel is found at the site of gaseous exchange?

capillaries

organic wastes

carry to sites of breakdown and removal

What are varicose veins?

caused by a loss of elasticity and resiliency in vein; weak valves or sagging of veins make valve incontinent so venous blood flow is further comprised; blood backs up into capillaries leading to tissue swelling

eosinophils

cells remove foreign compounds that have reacted with antibodies; rapid rise occurs in allergic reaction or parasitic infection

atherosclerosis

characterized by changes in the inner tunic vessel, followed by an 1) accumulation of blood lipids in the inner wall of blood vessel, 2) invasion of monocytes/macrophages, and 3) abnormal smooth muscle cell division

What does varicose veins increase the risk of?

clots; can be very painful

What are capillaries?

consist of only endothelium and basement membrane; specialized protein layer separating endothelial cells from underlying connective tissue

What are fenestrated capillaries?

contain windows/pores; found in endocrine organs, choroid plexus, intestines, and kidneys

pernicious anemia

deficiency of vitamin B12 so the RBCs can't mature normally; have low hematocrit and large RBCs with bizarre shapes; may be due to vitamin deficiency or loss in gastric parietal cells responsible for production of intrinsic factor necessary for vitamin B12 absorption

NK cells

destroy abnormal tissue cells like cancer cell; surveillance

B cells

differentiate into plasma cells that make antibodies that attack invaders

What are muscular arteries?

distributing arteries that can have internal and external elastic membranes

embolus

drifting blood clot that when it gets stuck, forms a blockage call an embolism

What blood vessels are most important for regulating blood pressure?

elastic arteries and arterioles

What comprises the tunica intern (intima)?

endothelium plus underlying connective tissue; has bigger vessels that contain an internal elastic membrane

T cells

enter tissue and attack foreign cells directly and fungi

fibrinigen

essential component of clotting system; under certain conditions, converted to fibrin, an insoluble major component of a clot; serum—what remains after whole blood is allowed to clot and the clot is removed

What does atherosclerosis lead to?

formation of fatty plaques in the walls of blood vessels that can obstruct blood flow;gaps in endothelial lining can cause platelets to stick and these can break free and lodge in small blood vessels leading to heart attacks/strokes

What are low-permeability capillaries?

found in the brain and testis; only vital and selective molecules cross these; pharmacologically restricts the delivery of certain drugs into these regions

nutrients

glucose, vitamins, fats, amino acids

Describe the small muscular artery.

greater than two layers of smooth muscle but no external elastic membrane; the change in diameter is controlled by the ANS and these vessels control general blood distribution

Describe the medium size distribution artery.

has a thicker tunica media with more smooth muscle content than elastin content

leukopenia

inadequate numbers of leukocytes; below 2500 indicates serious disorder; would be seen in immunosuppressive disorders

hemophilia

inherited disorder whereby person makes inadequate supply of clotting proteins; 80-90% are males; have extensive bleeding accompanying even the slightest cut or develop severe hemorrhages at joints-easily bleed to death

lipoproteins

lipids that are insoluble in water, but when combined with albumins or globulin, they are readily dissolved in plasma

What comprises the tunica media?

made of smooth muscle layers; may contain an external elastic membrane; may also contain elastic fibers throughout the layer; this layer is important for vasoconstriction/vasodilation

erythropoiesis

making of RBCs; erythropoietin- factor stimulating RBC production

leukopoiesis

making of WBCs; initially started in bone marrow and thymus, these cells can seed other lymphoid organs where they retain ability to divide and differentiate

What are the two types of muscular arteries?

medium size distribution artery and small muscular arteries

basophils

migrate to sites of injury or invasion by foreign materials and then cross blood vessels walls where they release histamine to exaggerate the inflammation response; increase blood flow to area; attract more infection fighting cells; also release heparin

regulatory proteins

minor components that include hormones and enzymes

What are the agranular WBCs?

monocytes/macrophages, and lymphocytes

Describe continuous capillaries.

most common type; have dimensional junctions between endothelial cells

proteins

mostly made by liver

Describe sinusoids.

much larger gaps; thinner wall; found in bone marrow, liver, and spleen

Describe arterioles.

much smaller in diameter; tunica media consists of only 1-2 layers of scattered smooth muscle cells; the diameter changes depending on the autonomics, hormones, and local tissue factors

sickle cell anemia

mutation in hemoglobin gene causing RBCs to become stiff and sickle shaped when they release oxygen; much shorter lifespan; because of weird shape can get stuck easier and block blood flow in vessels-painful and organ damage

capillary plexus (bed)

network of interconnected capillaries

What WBC is the most prevalent in the bloodstream?

neutrophils

What are the granular WBCs?

neutrophils, eosinophils, and basophils

electrolytes

normal ion composition and concentration needed to maintain cellular activity

What comprises the tunica externa (adventitia)?

outer connective tissue; anchors blood vessels to outside tissue

gases

oxygen and carbon dioxide

hematopoiesis

process of blood formation; stem cells for blood are called hematopoietic stem cells-make all blood cells but in different steps; occurs in red bone marrow found in vertebrae, sternum, ribs, skull, pelvis, scapulae, and proximal ends of limb bones

anemia

reduction in oxygen-carrying capacity of blood causing premature fatigue, weakness and lack of energy; low hematocrit or low oxygen carrying capacity

What are elastic arteries?

referred to as conducting arteries because they conduct blood from the heart to muscular arteries

monocytes/macrophages

remain in circulation then once entered tissue turn into macrophages; while engulfing foreign material, release chemicals that attract and stimulate other macrophages; also recruit fibroblasts

venules

resemble capillaries but larger and no smooth muscle; may have pericytes; have tunica interna and tunica externa; no real tunica media

lymphocytes

responsible for immunity-ability to mount a customized attack against invading pathogens/proteins on an individual basis

Describe RBCs.

shaped like a double con caved disk; very flexible and can shape; takes about 30 secs to make single trip around circulation; lifespan is about 120 days; can't repair themselves because they lack a nucleus and the protein making machinery

venous valves

small flaps within the veins that keep blood moving toward the heart; prevents back flow; important in keeping blood flowing particularly in the limbs

platelets

small pieces shed from specialized cells called megakaryocytes, sometimes called thrombocytes; lifespan of 5-10 days; 35,000 found in blood

What is the elastin membrane?

special kind of noncellular protein complex found outside the cells that is stretchable and organized as a sheet; encircles the wall of larger blood vessels

neutrophils

specialize in engulfing debris and digesting bacteria; also release bacteria-destroying substances

rouleaux

term used to describe the stacking up of RBCs in a small capillary; facilitates their passage through small capillaries

What happens to an elastic artery after a bolus of blood passes through?

the elastin causes the artery to recoil, which helps dampen the changes in blood pressure between ventricular contractions

What are arterioles function?

they are important for blood pressure regulation and directing blood flow

Name characteristics of elastic arteries.

they have thinner walls considering the diameter of the artery, they are rich in elastin with fewer smooth muscle cells in tunica media layers

large size veins

thickest layer is tunica externa; may contain longitudinal smooth muscle in tunica externa

What is the overall microscopic organization of blood vessels?

three layers that are called tunics, the average person has 60,000 miles of blood vessels

What is the function of hemoglobin?

to combine with oxygen and can easily release it; carbon dioxide binds and is released from the hemoglobin just as easily

leukocytosis

to many leukocytes; more than 11,000 indicates possible disorder; if greater than 100,000, suggests some form of myeloid leukemia or lymphoma

What is the primary function of RBCs?

to transport oxygen and carbon dioxide

polycythemia

too many RBCs; usually caused by cancer; increases blood viscosity that can cause vessel blockage; heart works harder

albumins

transport of lipids and steroid hormones; major contributor of osmotic concentration; helps regulate fluid balance between blood and tissues

What are the three layers of tunics called?

tunica interna (intima), tunica media, and tunica externa

What are the four types of veins?

venules, small and medium size veins, large size veins, and venous valves

venous thrombosis

very common; blood clotting due to sluggish blood flow or after bone fracture; in limbs, clots can form veins and if they break free, can lead to death if they enter the heart or lungs

What are the main components of plasma?

water, electrolytes, nutrients, organic wastes, gases and proteins

thrombus

when platelets begin to stick to wall of vessels and accumulate at the site; can be caused by ruptured platelets or a crack in the endothelial lining-initiates clotting

small and medium size veins

you can see all 3 layers in this group; have a thin tunica media with a thicker tunica externa; occasionally elastic fibers are present in larger of this class