Exam II Flashcards
How are blood vessels named?
- body region they traverse or bone next to them
- structure that is supplied
- arteries and veins that travel together are typically named similarly
What is the difference between the systemic and pulmonary systems?
- systemic circulation consists of the blood vessels that extend to and from the body tissues
- pulmonary circulation consists of the vessels that take the blood to the lungs for gas exchange and then return oxygenated blood to the heart
What are the three main classes of blood vessels?
arteries, capillaries, veins
What are anastomoses?
- site where two+ vessels merge to supply the same body region.
- arterial anastomoses can provide alternate blood supply routes to tissues or organs
- veins form more anastomoses than arteries
What is the difference between anatomical end arteries and functional end arteries?
Anatomical:
-vessels whose terminal branches do not anastomose. zIf those vessels become blocked the tissue will be deprived of oxygen and an infarct develops
Functional:
-anastomoses that are so small that they may be considered end arteries
What are tunics?
-these form the wall of the blood vessels and surround the lumen, there are three in blood vessels
What are the three tunics of the vessels and what are their characteristics?
tunica intima:
-the inner most layer of of the vessel wall
-composed of simple squamous epithelium aka endothelium
tunica media:
-middle layer of the vessel wall
-composed of circularly arranged layers pf smooth muscle cells under autonomic control (vasodilation nd vasoconstriction)
-arteries have a larger one
tunica externa/adventitia:
-outermost layer
-composed of areolar CT with collagen and elastic fibers and nerve fibers
-helps anchor the vessel to other tissues, protects and supports vessels
What is the vasa vasorum?
- found on the tunica adventitia
- small blood vessels that supply the cells of the vessel wall
What are the differences in structure and function between the veins and arteries?
Arteries:
-narrower than vein, wall is thicker than vein, retains circular cross sectional shape, thickest tunic is tunica media, more elastic and collagen fibers than in a vein, bp is higher than in vein, transports blood away from heart to body, system blood is high in O2 and pulmonary is low in O2
Veins:
-wider than artery, though collapsed, thinner than an artery, cross section is flattened and collapsed, thickest tunica is tunica externa, less elastic and collagen fibers, low bp, transports blood from body to heart, ssystemic has blood low in O2 and pulmonary has blood high in O2
What are the three basic types of arteries? How does the diameter change?
- elastic arteries
- muscular arteries
- arterioles
-as an artery’s diameter decreases there is a decrease in elastic fibers and increase in smooth muscle
What are some characteristics of elastic arteries?
- conducting arteries, largest diameter
- thick walled, near heart
- high proportion of elastic fibers through tunica media
- dampen bp changes associated with heart contraction
- passive accommodation results in smooth flow of blood
- aorta, pulmonary arties, brachiocephalic trunk, common carotid, and iliac
What are some characteristics of muscular arteries?
- medium diameter
- thick tunica media, more smooth muscle
- elastic fibers restricted to internal and external elastic lamina
What are some characteristics of arterioles?
- smallest diameter
- generally less than 6 layers of smooth muscle in tunica media
- loss of layers with decreasing size
- under autonomic control -> constriction reduces blood flow and dilation increases blood flow
What are the common arterial disorders?
arteriosclerosis- hardening of the arteries
atherosclerosis- fatty deposits and occlusion
hypertension
aneurysm- ballooning and/or rupture of the vessel
-cardiac and cerebral infarct results from the occlusion of the lumen of the arteries causing morbidity
What is atherosclerosis?
-slow, complex disease in which fatty deposits/plaque build up in the inner lining of the artery, eventually causing it to narrow and restrict blood flow
What is the response to injury hypothesis?
A repeated injury, such as infection or trauma, causes an endothelial inflammation response and that inflammatory response leads to the development of plaques in the arteries
What are some risk factors of atherosclerosis and some treatments?
Risk Factors:
- genetics
- hypercholesterolemia
- sex (male)
- age
- smoking
- hypertension
Treatments:
- angioplasty
- surgery
What, in general, are capillaries?
- smallest blood vessels that connect arterioles and venules
- slightly larger than the diameter of an erythrocyte
- contain only the tunica intima (basement membrane and endothelium)
- allow gas and nutrient exchange between the blood and the body tissues to occur rapidly
What is the sequence of blood movement through a capillary bed?
terminal arteriole -> metarteriole -> pre-capillary sphincter controls blood flow into capillary -> true capillaries -> thoroughfare channel -> capillaries rejoin -> post-capillary venule
What are the three basic kinds of capillaries? And which one is the most common? Which ones are more “leaky?” Where are these capillaries found?
- continuous capillaries (most common): muscle, skin, lungs, CNS
- fenestrated capillaries (leaky): GI tract, kidney, endocrine glands
- sinusoids or discontinuous capillaries (leaky): suprarenal glands, spleen, liver, ant pituitary
What, in general, are veins?
- drain capillaries and return the blood to the heart
- walls are thin and lumen is large
- systemic carries deoxygenated to the right atrium and pulmonary carry oxygenated blood to the left atrium
- bp is reduced
- holds about 60% of body’s blood at rest
- function as blood reservoirs
- tunica externa is thickest
- tunica media has less muscle and more elastin
How do veins prevent pooling of blood?
- valves found in the veins allow for one way flow and prevent backflow
- assist in moving the blood back to the heart
What is a prominent method utilized to pump the blood back to the heart?
Skeletal muscle pump:
-as the skeletal muscles contract, veins are squeezed to help pump the blood toward the heart
What are varicose veins? Risk factors? Treatments?
tortuous veins
- valves are nonfunctional causing blood to pool
- veins balloon out due to excess of blood sitting in them
- common in lower limbs
- genetics, aging, stress (standing, pregnancy, obesity)
- sclerotherapy: irritant injected into smaller veins to cause scarring and closure
- vein ablation: heat vein using a catheter until the vein closes
What is deep vein thrombosis? Causes? Treatments?
- blood clot or thrombus, most serious complication is SE
- common in sural (calf) or femoral (thigh) region
- causes: pregnancy, “economy class syndrome”
- treatment: anticoagulant
What is blood pressure measuring? What is hypertension?
- measured in mm Hg, force blood applies to the walls of blood vessels
- systolic (ventricular contraction, 120)
- diastolic (during ventricular relaxation, 70)
- hypertension: chronically elevated bp, 5-10% cases is secondary yo another disease
- damage to a vessel can cause a thickening of the wall
What is pulmonary circulation?
- system that carries deoxygenated blood from the right side of the heart to the lungs and returns newly oxygenated blood to the left side of the heart
- blood is pumped into the pulmonary trunk and bifurcates into a left and right pulmonary artery
- veins carry oxygenated blood and arteries carry deoxygenated blood
What, in general, are blood vessels?
- an efficient mode of transport for oxygen, nutrients, and waste products to and from body tissues
- heart mechanically pumps blood through the vessels (2 pumps in series)
- heart and vessels form a closed loop system
- blood is continuously pumped to the tissues
- vessels are not rigid and immobile
- can pulsate and change in shape and course due to bodily needs
Where is arterial supply from the head and neck usually supplied from?
- common carotid (neck, face, ant brain)
- vertebral from subclavian to post brain
Where is the circle of Willis located?
-sella turcica
What are the branches of the abdominal aorta?
- to diaphragm (inferior phrenic)
- GI tract (celiac, sup. and inf. mesenteric)
- other organs not part of the gut (suprarenal, renal, gonadal)
- to the body wall (lumbar arteries, analogous to intercostal arteries)
What is the hepatic portal system?
- a venous network that drains the GI tract and shunts the blood to the liver for processing and absorption of transported materials.
- blood exits the liver through hepatic veins that merge with the inf. vena cava
- is needed bc the GI tract absorbs digested nutrients, and these nutrients must be processed and/or stored in the liver
What artery is the primary provider of oxygenated blood to the lower limb?
internal iliac artery
What are the three sources of blood to the thoracic wall?
- axillary _> supreme thoracic and lateral thoracic
- subclavian -> internal thoracic/mammory -> ant. intercostal branches
- aorta -> intercostal arteries
What is CABG?
coronary artery bypass graft, typical bypass involves grafting the great saphenous vein or newer procedure involves the left internal thoracic artery
How does aging affect the cardiovascular system?
- heart and blood vessels become less resilient
- elastic arteries are less able to withstand the forces from the pulsating blood
- systolic blood pressure may increase with age
- apt develop an aneurysm and wall is more prone to rupture causing major bleeding and death
- incidence and severity of atherosclerosis increases
- skeletal pump system begins breaking down causing edema and varicose veins
What type of epithelium does the neural tube have? Why is this special?
pseudostratified columnar
bipotential -> differentiate into either glial or neuronal progenitor cells
What are glial cells responsible for?
supporting cells of the CNS. Insulate, nourish, support, and protect neurons
What are the three layers in the developing spinal cord? What cells can be found in each layer?
inner most: ventricular- ependymal cells, radial cells, mitotic cells
middle: mantle (gray matter)- young neuron, radial glia, glioblast
outer most: marginal layer (white matter)- neuroepithelial cells, neuron
What do glioblasts differentiate into?
astrocytes and oligodendrocytes
How is nerve differentiation in the spinal cord regulated?
- BMP4 and BMP7 secreted in the ectoderm establish a signaling center in the roof plate
- BMP4 in the roof plate upregulated a cascade of TGF-beta proteins, including BMP5 and 7, activin, and dorsalin
- SHH from the notochord establishes additional SHH signaling on the floor plate
-overlapping gradient involving the dorsal and ventral factors is established in the neural tube
What are the three types of mesoderm located laterally to the notochord and what will they eventually form?
paraxial mesoderm- longitudinal blocks of tissue on either side of the notochord. Gives rise to the axial skeleton and skeletal muscle
intermediate mesoderm- gives rise to urogenital system
lateral plate mesoderm- fives rise to CT and skeleton of the limbs and smooth muscle and CT viscera and blood vessels. NO SKELETAL MUSCLE
What are the segmented blocks of tissue on either side of the notochord called? What type of mesoderm differentiates into it?
- body -> somites
- head -> somitomeres
- paraxial mesoderm
Segmentation is controlled by the expression of what gene? What pattern does it follow to create a somite?
- Hox gene
- Hox genes oscillate longitudinally
What is a clock and wavefront model? What is this used for?
- used for creating somites
- peak and fall of Hox genes in different areas of the mesoderm, this shows where a single somite is going to be formed
What protein actually breaks up the blocks of mesoderm? How is this accomplished?
-The Notch protein accumulates in presomatic mesoderm destined to form the next somite and then decreases as that somite is established. The increase in Notch activates other segment patterning genes that establish the somite
What controls the boundaries in the somite?
- retinoic acid, FGF8 and WNT3a
- RA is higher concentration cranially and decrease caudally
- FGF8 and WNT3a are in higher conc caudally
- these overlapping expression gradients control the segmentation clock and activity of the Notch pathway
How are creatures that are more segmented develop in terms of number of somites?
-the clock component is four times faster in a snake (relative to growth rate) than short bodied animals leading to smaller, shorter somites