CV System Physiology 1 Flashcards
(109 cards)
What blood vessel is involved in nutrient and waste exchange?
Capillaries. Their walls are thin enough to allow for exchange.
What are the 3 types of capillaries?
Continuous
Fenestrated
Sinusoidal
What type of capillary excludes proteins and cells from passing through?
Continuous
What type of capillary excludes cells? Where are they found?
Fenestrated. Found in the kidney
What type of capillary allows cells and protein to pass through? Where are they found?
Sinusoidal/discontinuous. Found in liver, bone marrow, spleen
What three layers are found in all blood vessels except capillaries?
(1) Tunica intima or interna
(2) Tunica media
(3) Tunica adventitia or externa
What property of blood vessels helps push blood through arteriole system?
Elastic tissue
What property of blood vessels does smooth muscle provide?
Its ability to contract and dilate allows blood to be shunted from one area to another
What protects blood vessels against distention?
The fibrous nature of the tissue
Which blood vessel layer contains collagen and elastic fibers?
Tunica adventitia
Capillaries are comprised of only one of these layers; which is it?
Tunica intima
Which blood vessel layer contains smooth muscle and thus is responsible for vasoconstriction and vasodilation?
Tunica media
What types of blood vessels are resistance vessels due to their smooth muscle?
Arteries and arterioles. Veins lack smooth muscle.
Which layer holds the vaso vasorum seen in larger vessels?
Tunica adventitia
Cardiac muscle is what kind of muscle
Involuntary striated with light (I bands) and dark (A bands) cross bands
Myocardial cells have more of this organelle due to its high oxidative capacity
Mitochondria. Oxidative phosphorylation occurs within the mitochondria.
What cellular feature allows the heart to contract in unison?
The presence of gap junctions between muscle cells allows for easy communication between myocytes.
How do T-tubules differ between cardiac and skeletal muscle cells?
Cardiac: T-tubules contain extracellular fluid high in calcium
Skeletal: T-tubules contain extracellular fluid low in calcium
What structure brings depolarization inside the cardiac muscle and helps regulate cytoplasmic calcium?
T tubules
What prevents tetanic contraction in cardiac muscle?
The long cardiac action potential
What aspect of the action potential prevents a second action potential from taking place?
The long refractory period or plateau period
True or false: the signal for myocardial contraction comes from the nervous system?
False - it comes from auto-rhythmic cells, also called pacemakers.
What is the originator of the cardiac action potential?
The SA node
The majority of calcium used in the heart for muscle contraction comes from what source?
The sarcoplasmic reticulum