Term
| What is the process by which blood cells are formed? |
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Definition
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Term
| How many new blood cells are formed eavh day? |
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Definition
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Term
| Where is Bone Marrow? What are the types? |
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Definition
Located w/in all bones
Red and yellow |
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Term
| What does Red Marrow do? Where is it? |
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Definition
actively generates new blood cells
remains in proximal epiphyses, girdles, and all of axial skeleton (infants and children, most bones contain bone marrow) |
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Term
| What is Yellow Marrow? Where is it? |
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Definition
Dormant
Contains many fat cells
in long bones in adults |
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Term
| What are the frameworks for red marrow? |
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Definition
1.Reticular connective tissue- reticular fibers suppor developing blood cells
2.Blood sinusoids- large capillaries with open intercellular junctions |
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Term
| All blood cells origniate from: |
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Definition
Blood stem cells:
1. Lymphoid stem cells- rise to lymphocytes
2. Myeloid stem cells- give rise to all other blood cells |
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Term
| What are erythrocytes formed from? |
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Definition
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Term
| What is the formation for leukocytes? |
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Definition
Granulocytes from from myeloblasts (one cell line from each)
Monocytes form from monoblasts |
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Term
| Where do Megakaryoctes form from? |
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Definition
| Megakaryoblasts -break apart into platelets |
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Term
| stages of differentiation of blood cells |
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Definition
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Term
| What are the types of blood vessels? |
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Definition
arteries
capillaries
veins |
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Term
| Describe Arteries Capillaries and Veins |
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Definition
Arteries- carry blood away from heart
Capillaries- smallest blood vessels- the site of exchange of molecules between blood and tissue fluid
Veins- carry blood toward heart |
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Term
| What is the structure of blood vessels? |
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Definition
Lumen- central blood filled space of vessel
Three tunics (layers):
1.Tunica intima
2. Tunica Media
3. Tunica Externa (adventitia) |
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Term
| What is the tunica intima composed of? |
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Definition
simple squamous epithelium= endothelium
Subendothelial layer- thin layer of loose CT; vessels are about 1 mm in diameter |
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Term
| What is the tunica media? |
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Definition
| primarily sheets of smooth muscls, also collagen and elastin (esp. in larger vessels) |
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Term
| What is the tunica externa (adventitia) |
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Definition
| composed of connective tissue |
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Term
| How to tell veins from arteries, bc they usually run together: |
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Definition
Veins:
thin walls
larger lumen/vessel size ration
thicker tunica externa (adventitia)
Arteries:
thicker tunica media
Smaller lumen/vessels ratio
More smooth muscle/ elastin |
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Term
| What are the types of arteries? |
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Definition
1. Elastic
2. Muscular
3. Arterioles |
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Term
| Describe Elastic Arteries |
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Definition
Largest (diameters 2.5-1cm)
Includes aorta and major branches
aka conducting arteries
high elastin in tunica media stores energy for continuous blood flow |
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Term
| Describe Muscular Arteries |
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Definition
Distributing
Lie distal to elastic
diameters 1-.3mm
Includes most of the named arteries
tunica media is thick
internal and external laminae |
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Term
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Definition
smallest arteries (d=.3mm-10um)
larger arterioles possess all three tunics
diameter of lumen can change: contraction of smooth muscle= vasoconstriction and relaxation= vasodialation
Diameter controlled by local factors in tissues and symphathetic nervous system |
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Term
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Definition
smallest blood vessels
d=8-10um
Red blood cells pass thru single file |
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Term
What are the site specific functions of capillaries?
lungs
small intestines
endocrine glands
kidneyes |
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Definition
lungs- O2 enters blood, CO2 leaves
small intestines- receive digested nutrients
endocrine glands- pick up hormones
kidneyes- remove nitrogenous wastes |
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Term
In capillaries, what holds together endothelial cells?
What are intercellular clefts? |
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Definition
held together by tight junctions nad desmosomes
intercellular clefts: gaps of unjoined membrane between tight junctions; overlap (small molecules enter and exit) |
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Term
| What are the two types of capillaries? |
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Definition
continuous- most common
fenestrated- have pores |
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Term
| What are the 4 routes of capillary permeability? |
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Definition
1. direct diffusion- lipid solubles
2. through intercellular cleft
3. thru fenestrations
4. thru cytoplasmic vesicles- pinocytosis |
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Term
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Definition
wide leaky capillaries found in some organs
-usually fenestrated
-intercellular clefts are wide open
Occur in bone marrow and spleen- sinusoids have large diameter and twisted course |
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Term
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Definition
network of capillaries running through tissues
Precapillary sphincters- regulate flow of blood to tissue
Metabolically inactive tissue have reduced blood flow through capillary beds |
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Term
| How do tendons and ligaments receive nutrients? |
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Definition
| since they are poorly vascularized, they receive them from nerby CT |
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Term
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Definition
conduct blood from capillaries toward heart
BP is lower than in arteries
smallest veins= venules*
-diameters 8-100um
-smallest venueles- called postcapillary venules
venules join to form veins
Tunica externa is the thickest region in veins- little smooth muscle in tunica media; mostly collagen |
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Term
| What are the mechanisms to counteract low venous pressure? |
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Definition
1. one way valves in some veins, particularly in limbs
2. skeletal muscle pump; muscles press against thin walled veins |
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Term
| What are vascular anastomoses? |
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Definition
vessels interconnect to form vascular anastomoses
oragan receive blood from more than one arterial source
Neighboring arteries form arterial anastomoses, provide collateral channels
Veins anastomose more freq than arteries |
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Term
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Definition
vessels of vessels: Nourish outer region of large vessels
inner half of large vessels receive nutrients from luminal blood
Tunica externa of large vessels have: tiny arteries, capillaries, and veins |
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