Week 6 Flashcards
Echogenic
Very bright on US, very good at reflecting sound waves
Hypoechoic
Grey on US, reflects few echoes
Anechoic
Black on US, Will not reflect sound waves. Ex. Fluids.
Doppler US
use it to quantitate flow
Duplex US
doppler flow superimposed on US image
Ultrasound
imaging modality that uses that acoustical energy to localize and characterize human tissues.
how ultrasound images are created
production of a high-frequency sound wave, the reception of a reflected wave or echo, and the conversion of that echo into the actual image.
major risks and benefits of ultrasound
- well tolerated.
- obtained relatively quickly,
- require no patient preparation other than abstinence from food before abdominal studies.
- short-term potential of causingminor elevation of heatin the area being scanned
- no known long-term side effects
Doppler effect
use to determine if an object, usually blood, ismoving towardor away fromthe transducer and at whatvelocityit is moving.
Pulmonary circulation
blood moving from right ventricle through the lungs to the left atrium
Systemic circulation
oxygenated blood being pumped from left ventricle, through aorta, into arteries, into capillaries, becoming deoxygenated, into veins, into vena cava, back to right atrium
Artery and types
- Carry blood under high pressure from heart to body tissue.
- Large elastic, medium muscular, small/arterioles
Large elastic artery
○ Many elastic layers which allow for them to expand from cardiac output pressure, minimizing pressure change
○ Return to normal size between ventricular contractions which maintains blood pressure
Ex. Aorta, brachiocephalic trunk, subclavian, and carotid arteries
Medium muscular
○ Walls are mostly of circular smooth muscle, allows for constriction and dilation to regulate flow of blood to different parts of body
○ Have pulsatile contractions to propel blood
○ Includes most arteries
Small arteries/arterioles
○ Narrow lumina and thick muscular walls
○ Degree of tonus in smooth muscles of arterioles walls controls filling of capillary beds and how high pressure is
○ Not usually named
Anastomoses
○ Occur between multiple branches of an artery as potential detours for blood flow in case normal path is obstructed or compressed
○ Can increase in size over time but cannot immediately handle the complete blood flow of main artery
True terminal arteries
do not contain anastomoses and if blocked there is no alternate pathway for blood to take in order to supply tissue (ex. retina)
Veins
○ Return lox-oxygen blood from capillaries to the heart
○ Pulmonary veins are the only veins that carry oxygenated blood (from lungs to heart)
○ Lower blood pressure allows for walls to be thinner than arteries
-Types: venules, medium, large
Venules
○ Drain capillary beds and form small veins
○ Will form tributaries and create venous plexuses
○ Unnamed
Medium veins
- what do they do?
- what do they have?
- what do they have to overcome? and how?
- names?
○ Drain venous plexuses
○ Follow same path as medium arteries
○ Venous valves are cusps that prevent gravity from taking blood back down by closing blood into a venous sinus; prevents backflow and reduces back pressure
○ Musculovenous pump overcomes the force of gravity to return blood back to heart
○ Include superficial veins and accompanying veins that are named according to the artery they follow
Large
- what are they made of?
- diameter? why?
- how much blood do they hold?
- what is ratio of artery vs veins
- anastomoses?
○ Wide bundle of longitudinal smooth muscle and well developed tunica afventita
○ Walls thinner, diameter larger; allows for large capacity to expand
○ 80% of blood occupies veins
○ Tend to run in double or multiples, with accompanying veins creating branching network as a countercurrent heat exchanger (warm arterial blood warms the venous blood as it returns to the heart
○ Venous anatomoses occur more frequently than arterial
Blood capillaries
-Connect the arterioles and venioles through capillary beds
○ Allow for exchange of material in extracellular fluid
As blood is pushed into the capillary it pushes the oxygen and nutrients out into the extracellular space; at venuole side of capillary the ECF contains waste and CO2 which is reabsorbed into the blood due to osmotic pressure from higher concentration of proteins within the capillary
○ Portal venous system: blood passes through two capillary beds before returning to heart
parietal pleura
side of pleura touching the body cavity
Visceral pleura
side of pleura touching the lung
