Cardiovascular System (EXAM #2) Flashcards
What is the overview of Cardiovascular System?
- Heart, Blood vessels, Blood
- Transport: gases, nutrients, hormones, wastes, heat
- Protection: disease, fluid loss (clotting)
Heart
In a cavity called the mediastinum (= space between lungs within thoracic cavity)
What are the structures of the Heart?
- Coverings = Pericardium
- Heart Wall
- Four chambers of the heart and associated blood vessels
- Septa (separate chambers)
- Cardiac (Fibrous) Skeleton
- Valves (for one way flow of blood)
- Cardiac Muscle Cells
Coverings = Pericardium
- Double-walled sac surrounding heart
- 3 layers:
- Fibrous Pericardium
- Perietal Pericardium
- Visceral Pericardium
- Between pericardial layers = pericardial cavity with serous fluid (lubricates)
Fibrous Pericardium
- Outermost layer = dense irregular connective tissue
- Anchors to surrounding strucutures e.g. diaphragm, great vessels (aorta, Vena Cava, etc)
Perietal Pericardium (Serous Pericardium)
- 2 layers - epithelial & connective
- Connected to fibrous pericardium
- Pericardial Sac
Visceral Pericardium (Serous Pericardium)
- = Epicardium
- 2 layerss - epithelial & connective
- Fused to heart surface, so is part of heart wall
Heart Wall
3 Parts:
1. Epicardium
2. Myocardium
3. Endocardium
Epicardium
Simple squamous epithelium and connective tissue
Myocardium
- = cardiac muscle
- Arranged in spiral/circular pattern, reinforced with connective tissue
Endocardium
- Simple squamous epithelium and connective tissue
- Epithelium named endothelium - lines inner surface of heart and ALL blood vessels
Four chambers of the heart and associated blood vessels
- Right Atrium
- Left Atrium
- Right Ventricle
- Left Ventricle
Right Atrium
- Three major veins connected to the right atrium that carry deoxygenated blood into the chamber:
- Inferior vena cava (carries blood from body below heart)
- Superior vena cava (carries blood from body above heart)
- Coronary Sinus (carries blood from the myocardium)
Left Atrium
- 4 veins carry oxygenated blood into the left atrium from the lungs:
- Left pulmonary veins
- Right pulmonary veins
Right Ventricle
1 artery, the pulmonary trunk exits the right ventricle and then divides to form 2 pulmonary arteries (left and right). These carry deoxygenated blood towards the lungs
Left Ventricle
1 artery, the aorta, exits the left ventricle and carries oxygenated blood to all organ systems
Septa (separate chambers)
- Interatrial Septum
- Separates atria
- Interventricular Septum
- Separates ventricles
Cardiac (Fibrous) Skeleton
- Fibrous connective tissue separating atria & ventricles
- Provides firm attachment point for cardiac muscles
- Forms solid rings around heart valves, base of aorta and pulmonary trunk that provide structural support for these structures and hold them in place
- Provides electrical insulation - prevents simultaneous contraction of atria and ventricles
Valves (for one way flow of blood)
- Atrioventricular (AV) valves
- Semilunar valves
Atrioventricular (AV) valves
- Bicuspid (mitral) valve
- Tricuspid valve
- Chordae Tendineae
Bicuspid (mitral) valve
- Between left atrium and left ventricle
- Has 2 sheet-like cusps composed of connective tissue
Tricuspid valve
- Between right atrium and right ventricle
- Has 3 sheet-like cusps composed of connective tissue
Chordae Tendineae
- Strings of connective tissue that attach atrioventricular valve cusps to papillary muscles that project from the ventricular myocardium
- Prevent eversion of cusps
Semilunar valves
- 3 cup-like cusps each
- Aortic
- Separates left ventricle & aorta
- Pulmonary
- Separates right ventricle & pulmonary trunk
- Aortic
Cardiac Muscle Cells
- Includes two cell types:
- Contractile cells
- Conduction System cells
Contractile cells
- Forms majority of myocardium
- Similarities to Skeletal muscle:
- Striated (myofibrils with sarcomeres)
- Has sarcoplasmic reticulum & T-tubules
- Differences:
- Branched (myofibrils with sarcomeres)
- Uninucleated discs = region where two fibers meet
- Contain anchoring and gap junctions
Conduction System cells
- Forms remainder of the myocardium
- Cardiac muscle cells that are modified to produce and conduct electrical impulses - DO NOT CONTRACT
- Have many gap junctions that help electrical signals to spread very quickly
What are the parts of Conduction System cells?
- Sinoatrial (SA) node
- Atrioventricular (AV) node
- Atrioventricular Bundle (Bundle of His)
- Atrioventricular (AV) Bundle Branches
- Purkinje fibers
Sinoatrial (SA) node
- In right atrium at base of superior vena cava
- Generates impulses the fastest - sets pace
Atrioventricular (AV) node
Base of right atrium
Atrioventricular Bundle (Bundle of His)
- Superior part of interventricular septum
- Electrically connects atria to ventricles
Atrioventricular (AV) Bundle Branches
Carry impulse to apex (bottom tip) of the heart
Purkinje fibers
- Terminal fibers in ventricles (not found in atria) that carry signals from apex upward to all parts of the ventricle
- NOTE: Electrical signal spreads from conduction system to contractile cardiac cells then they contract
What are the general structures of blood vessels?
- Tunica externa - CT
- Tunica Media
- Tunica intima/interna
- Lumen
Tunica Media
- Smooth muscle
- Elastic Fibers (CT)
Tunica intima/interna
- Endothelium - simple squamous epithelium
- Continous with endocardium