Test 3 - Cardiovascular Flashcards
Systemic circulation
heart to body tissues and body tissue to heart
Pulmonary circulation
heart to lungs and lungs to heart
Portal circulation/systems
vein/arteriole between 2 capillary beds
What are the three wall layers of vessels?
- tunica intima
- tunica media
- tunica adventitia
What is found in the tunica intima?
- simple squamous epithelium
- basal lamina (collagen & proteoglycans)
- subendothelial layer (loose CT)
What is found in the tunica media?
mainly smooth muscle
What is found in the tunica adventitia?
mainly CT
What is endothelium?
epithelium that lines blood vessels
When discussing the 3 layers of vessels, which layers is most responsible for blood pressure maintenance?
tunica media (smooth muscle)
What is vasodilation?
relaxing of smooth muscle (decrease resistance, decrease blood pressure, increase lumen size)
Name a vasodilator.
Nitric oxide (NO)
What is vasoconstriction?
contraction of smooth muscle (increase resistance, increase blood pressure, decrease lumen size)
Name a vasoconstrictor.
ET-1 (endothelin 1), absence of NO
Compare and contrast large arteries and large veins.
arteries: large tunica media, circular lumen
veins: large tunica adventitia, irregular lumen
Why are there histological differences between arteries and veins?
from the difference of blood pressure - arteries have an increase in pressure to pump blood to the entire body therefore need more muscle
What would you find in a microcirculatory bed?
arterioles, venules, AV shunts, capillaries, precapillary sphincters, thoroughfare channel
What is a microcirculatory bed?
where arterioles regulate blood flow to capillary networks
AV shunts and functions.
- allows blood to bypass capillaries
- arteriole-ventriole direct connection
Steps of arteriole-ventriole direct connection
- open shunt
- close sphincter
- blood doesn’t go to capillaries, uses bypass
What tissues make up the epicardium?
mesothelium, CT, adipose (outside of heart)
What tissues make up the myocardium?
cardiac muscle
What tissues make up the endocardium?
3 layers:
1. inner (endothelium, CT)
2. middle (CT, smooth muscle)
3. deeper/subendocardial layer (CT, Purkinje cells)
Describe the histology of the heart walls
cardiac muscle
fibrous skeleton for muscle attachment
internal conducting system
Describe the histology of the heart valves
CT and and endocardium
Has 3 layers
What are the 3 layers of the heart valve?
- spongiosa: atrial side (collagen & elastic fibers)
- fibrosa: middle (dense irregular CT)
- ventricularis: ventricular side (dense irregular CT with elastic fibers) - continuous with chordae tendinae
How does the histology of the heart walls and heart valves make sense when regarding their functions?
walls - a lot of muscle because it contracts
valves - elastic because stretches when opens and closes
Describe the regulation of heart rate (steps)
SA node -> Av node -> fibrous skeleton -> L&R branches -> Purkinje fibers -> Calcium transduction
Sinoatrial node:
- pacemaker
- sets up atrial contraction
- first to respond to ANS
- fastest rate of depolarization
AV node:
- ventricular contraction
- bundles of His divided into L&R branches and Purkinje fibers
- carries impulses over fibrous skeleton using His bundles
ANS in terms of heart regulation
- parasympathetic: increase ACH -> bradycardia
- sympathetic: increase NER -> tachycardia
