Cardiovascular system
Transport of blood and lymph to and from organs
Consist of the heart, blood vessels, and lymph vessels
Closed system in vertebrates, open in invertebrates
Closed system
Blood is always maintained within a series of tubes (vessels)
Found in vertebrates
Open system
Blood (aka hemolymph) leaves the vessels and contacts cells directly
Found in invertebrates
Coronary circuit
Blood flow through the heart tissue and back to the heart
Pulmonary circuit
Heart to lungs and back
Systemic circuit
Everything else besides the coronary and pulmonary circuits
Blood flow goes from the _______ –> _______ –> _______ –> _______ –> _______ –> _______ –> _______.
heart; arteries; arterioles; capillaries; venues; veins; heart
Arterioles and venules comprise the _______.
microvasculature
Arteries and veins comprise the _______.
macrovasculature
Portal blood flow
Capillary to a vein to a capillary
Hepatic portal system
Hypothalamal hypothoseal portal system
Heart
4 chambered organ with 4 layers of tissue
Cardiac muscle cells
What are the four layers of heart tissue?
- Epicardium
- Pericardium
- Myocardium
- Endocardium
Epicardium
Epithelial serous membrane covering the heart
Pericardium
Membrane that envelops the heart as it grows
2 layers
Myocardium
Thick, muscular layer of the heart
Endocardium
3 thin separate layers of the heart
- Endothelium
- Subendothelial layer
- Subendocardial layer
Endothelium
Layer of the endocardium layer of the heart
Simple squamous epithelium
Makes contact with the blood
Subendothelium layer
Layer of the endocardium of the heart
Made up of CT fibers such as elastin and collagen
Subendocardial layer
Layer of the endocardium layer of the heart
Made up of CT fibers such as elastin, collagen, and conducting fibers
Purkinje fibers
Conducting fibers in the subendocardial layer of the heart
Initiate and transport action potentials
Cluster of large cells; non-contractile, modified muscle cells
Pacemakers take over for the _______ when it malfunctions.
SA node
The heart has a fibrous _______ running throughout the heart muscle that forms the _______.
skeleton; valves
The two heart valves are the _______ (aka _______ valve) and the _______ valves.
bicuspid; mitral; tricuspid
The aortic and pulmonary valves are also formed by the _______.
fibrous skeleton
The heart has _______ innervation.
dual
The heart is innervated by the _______ and _______ nervous systems, which are both branches of the _______ nervous system.
sympathetic; parasympathetic; autonomic
Sympathetic innervation of the heart
Increases rate and force of contraction
Mediated by norepinephrin
2 sympathetic accelerating nerves
β-1 receptors
Parasympathetic innervation of the heart
Decreases rate and force of contraction
Mediated by acetylcholine
Vagus nerve (X)
Muscarine receptor
Capillaries
Tiny numerous bv that are the site of exchange between cells and blood
Made up of simple squamous epithelium (endothelium) anchored to a basement membrane
Have pericytes on top of cells
Pericyte
Contractile cell with actin, myosin, and tropomyosin that sit on cells of capillaries
Help in healing wounds
Continuous capillary
Has zona occludens for tight junctions and inhibition of paracellular movement
Forms the BBB
Fenestrated capillary
Has fenestrations in the cell membrane with a very thin diaphragm (thinner than the cell membrane)
Found in places where you need quick exchange, such as the kidneys, endocrine cells, and the intestine
Sinusoidal capillaries
Have large spaces between cells with no basal lamina covering the spaces, only covering the individual cells
Allows RBC exchange
Found in the spleen and bone marrow
Blood vessels have 3 layers, or _______, called _______, _______, and _______.
tunics; tunica intima; tunica media; tunica adventitia
Tunica intima
Innermost tunic of a blood vessel
Simple squamous epithelium (endothelium)
Has a sub endothelial layer that anchors and separates this tunica from the next tunic
Tunica media
Middle tunic of a blood vessel
Smooth muscle that recoils and stretches
Tunica adventitia
Outermost tunic of a blood vessel
Fibrous CT surrounding the entire tube
Continuous with surrounding tissue
Internal elastic membrane
Condensation of elastic fibers found between the tunica intima and tunica media
Found mainly in arteries; small amounts may be found in other bv
External elastic membrane
Condensation of elastic fibers found between the tunica media and tunica adventitia
Only found in large arteries
Vasa vasorum
“bv of the bv”
Blood supply for very large vessels, such as the aorta and the vena cavas
Bv is so thick in these vessels that it needs its own supply of blood, nutrients, and waste elimination
Found in the tunica media of these vessels
What regulates the diameter of bv?
Nerve fibers
Sympathetic nerve innervation of bv
Release of norepinephrine makes the bv contract, making the lumen smaller (less blood flow)
Important in arterioles, the main vessels for blood flow regulation
Sympathetic nerve fibers terminate in the _______ and release _______, where it must diffuse through the tunics to get to receptors on _______ muscle.
tunica adventitia; norepinephrine; smooth
Relaxation of bv can be _______ or _______.
passive; active
Passive relaxation of bv is due to _______.
lack of norepinephrine when there is no sympathetic innervation
Active relaxation of bv is due to _______.
acetylcholine release of parasympathetic innervation
Parasympathetic active relaxation of bv
ACh released –> Nitric oxide production –> diffuses to sm. muscle –> activates guanylyl cyclase –> forms cyclic GMP –> activates kinase G –> SERCA –> no contraction (larger lumen, therefore more blood flow)
SERCA
Ca+ pump on SER
Pumps Ca+ into SER out of muscle cytoplasm
Nitric oxide
NO
Toxic
Cells use to communicate
Artery
Very thick tunica media
No valves except for semilunar valves of pulmonary artery and aorta
Vein
Very thick adventitia
Large veins have modified tunica intima that forms valves
Valve
Specialization of tunica intima that prevents back flow of blood
Found in veins, pulmonary artery, aorta
Varicose vein
Swollen, discolored vein close to skin surface
Can develop phlebitis, which can lead to clots that can become a thrombus and clog vessels
Phebitis
Inflammation of a vein