HISTO - Circulatory System Flashcards
What are the major functions of the Circulatory system?
Transportation
- Nutrient and oxygen
- waste
- Hormones
What are the 4 chambers of the heart and what do they do?
2 atria = receiving chambers
2 Ventricles = discharging chambers
_____ is the pump for the systemic circuit.
Left side of heart
______ is the pump for pulmonary circuit.
Right side of heart
_____ receives oxygenated blood.
Left atrium
_____ Receives deoxygenated blood.
Right atrium
The Heart wall contains what 6 structures/tissues?
- Cardiac muscle
- Fibrous skeleton of the heart.
- 4 fibrous rings surrounding valve orifices.
- 2 fibrous trigones connecting rings
- membranous portion of inter ventricular and inreratrial septa. - Intrinsic conduction system
- Coronary vasculature
- A serous membran
- Endothelial cells and underlying connective tissue.
What are the 3 layers of the heart?
Epicardium = outer layer, viceral layer of serous pericardium. Myocardium = middle layer, composed primarily of the cardiac muscle (also contains the fibrous skeleton of the heart.) Endocardium = inner layer with 3 components.
What are the 3 layers of the Endocardium?
- endothelial layer - inner layer
- underlying layer - of dense connective tissue and smooth muscle.
- Connective tissue (deepest layer) contains the intrinsic conduction system.
There are 4 valves associated with the heart,, what are they and what is their function?
Two Atrioventricular Valves (prevents back flow into atria):
1. Tricuspid Valve
2. Bicuspid or Mitral Valve
Two semilunar Valves (Prevent back flow into ventricles)
1. Aortic Semilunar valve
2. Pulmonary semilunar Valve.
True or false, there are no valves associated with the entrances of venue cavae, coronary sinus and pulmonary veins into the heart.
True
The Heart valves are composed of ______ with overlying _______.
- Connective tissue
- overlying endocardium
What are the 3 layers of the Heart valves?
- Spongiosa - loose connective tissue covered in endothelium; located on atrial or blood vessels side of valve; loosely arrange collagen and elastic fibers infiltrated with proteoglycan; shock absorber.
- Fibrosa - core of valve; contains fibrous extensions from the dense irregular connective tissue of skeletal rings of heart.
- Ventricularis - dense connective tissue with layers of elastic fibers covered in endothelium; adjacent to ventricular side of the valve.
The cardiac muscle of the heart is able to depolarize and contract without imposes from the Nervous system….What makes this possible?
The Intrinsic cardiac conduction system.
Describe the 4 Fascinating facts about the intrinsic cardiac conduction system…
- Composed of 1% cardiac conduction cells (auto-rhythmic cells) that are self excitable can can dendrite action potential w/out nervous system input.
- These cells are organized into nodes and tracts called perkinje fibers.
- These cells are responsible for the ignition and distribution of impulses throughout the heart.
- Rate of cardiac muscle contraction is set by these pacemaker cells. Pace can be altered by sympathetic and parasympathetic divisions of autonomic NS. * hormones can also impact intrinsic rate.
Describe the 5 steps of the excitatory sequence of the auto rhythmic cardiac cells….
- Sinoatrial node = the pacemaker of heart: determines heart rate through its sinus rhythm.
- Atrioventricular node = impulse travels to AV node via the internodal pathway or tracts; impulse is dealer here for 0.1s to allow for atria to contract.
- Atrioventricular bundle = impulse travels from AV node to right and left bundles; only electrical connection between atria and ventricles; travels across the fibrous skeleton.
- Right and left bundle branches = branch of the AV Bundle; course toward apex of heart through interventriuclar septum.
- Purkinje fibers (subendothelial fibers) = finish pathway in inter ventricular septum, around apex of heart, and head back towards atria.
What are the 2 main cells of the intrinsic conduction system?
Nodal Cardiac cells
Purkinje fibers
Describe the Nodal Cardiac cells… (4)
- Found in SA and AV nodes.
- Modified Cardiac muscle cells.
- smaller than surrounding atrial contractile cardiac cells.
- contain fewer myofibrils and lack intercalated discs.
Describe the Perkinje fibers….(8)
- Found in AV bundle, bundle branches and sub endothelial branches
- modified cardiac cells
- larger that surrounding ventricular contractile cells.
- contain myofibrils at periphery of cell.
- nuclei are round and larger
- Have associated intercalated discs
- Positive for PAS staining because of glycogen.
- with H&E stain glycogen rich center of cell appears homogenous and stains pale.
What are the three major types of blood vessels?
Arteries - carry blood away from heart.
Capillaries - smallest blood vessels; thin wall ; main role is to allow the exchange of materials between the blood and body tissues.
Veins - carry blood towards the heart.