Cardiovascular System Flashcards
Cardiovascular System Overview
- Heart, blood vessels, blood
- Transport: gases, nutrients, hormones, wastes, heat
- Projection: disease, fluid loss (clotting)
Heart Overview
- In a cavity called the mediastinum (=space between lungs within thoracic cavity)
- Structure:
1) Coverings
2) Heart Wall
3) Chambers and associated blood vessels
4) Septa
5) Fibrous Skeleton
6) Valves
7) Cardio Muscle Cells
8) Conduction System
Coverings
- = pericardium
- double-walled sac surrounding heart
- 3 layers:
1) Fibrous Pericardium
2) Serous Pericardium (2 parts)
Fibrous Pericardium
- Outermost layer = dense irregular CT
- Anchors to surrounding structures (e.g. diaphragm, great vessels
Serous Pericardium (2 parts)
- Between pericardial layers = pericardial cavity with serous fluid (lubricates)
1) Parietal Pericardium: - Fused to fibrous pericardium (made of CT and Epithelial tissue)(Fibrous pericardium and parietal pericardium = pericardial sac)
2) Visceral Pericardium (=epicardium) - fused to heart surface, so is part of heart wall
Heart Wall
- 3 parts:
1) Epicardium - stratified squamous epithelium and CT
2) Myocardium - = Cardias muscle
- arranged in spiral/ circular pattern, reinforced with CT
3) Endocardium - Simple squamous epithelium and CT
- Epithelium named endothelium - lines inner surface of heart and ALL blood vessels
Chambers and associated blood vessels
1) Right Atrium
- inferior and superior vena cava
- coronary sinus (posterior)
2) Left Atrium
- 4 pulmonary veins
3) Right Ventricle
- Pulmonary trunk - divides to form 2 pulmonary arteries
4) Left Ventricle
- Aorta
Septa (Separate chambers)
1) Interatrial Septum
- Separates atria
2) Interventricular Septum
- Separates ventricules
- Deep to interventricular Sulcus (external)
Fibrous Skeleton
- CT fibers around the muscle fibres + CT rings between atria + ventricles at the coronary sulcus
- Allows openings to remain open at all times
- Provides electrical insulation - prevents simultaneous contraction of chambers
Atrioventricular (AV) Valves
Chordae Tendineae (connective tissue) attach AV valve cusps to papillary muscles (projections of myocardium) - prevents eversion of cusps
1) Bicuspid (mitral) valve:
- Left side - 2 cusps
2) Tricuspid Valve
- Right side - 3 cusps
Semilunar Valves
- Each have 3 cusps
1) Aortic - Separates left ventricle + aorta
2) Pulmonary - Separates right ventricle + pulmonary trunk
Cardiac Muscle Cells
Form both contractile myocardium + conduction system
Similarities from muscle cells to skeletal cells
1) Striated (myofibrils with sarcomeres)
2) Has sarcoplasmic reticulum and T-tubules
Differences from muscle cells to skeletal cells
1) Branched (Myofibrils with sarcomeres)
2) Uninucleated
3) Intercalated discs = region where two fibers meet
- Contain anchoring and gap junctions
Conduction System
- Cardiac muscle cells modified to produce and conduct electrical impulses -DO NOT CONTRACT
- Parts:
1) Sinoatrial (SA) node
2) Atrioventricular (AV) node
3) Atrioventricular Bundle (Bundle of His)
4) Atrioventricular (AV) Bundle Branches
5) 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 inter ventricular septum
- Electrically connects atria to ventricles
Atrioventricular (AV) Bundle Branches
Go to each ventricle
Purkinje Fibers
Terminal fibers in ventricles only
Circulatory Routes
-Closed, double circulation
Closed= blood confined to heart + blood vessels
Double = 2 routes (pulmonary + Systemic)
Adult Pulmonary Circulation
1) Right ventricle to lungs via pulmonary arteries (deoxygenated blood)
2) Pick up oxygen in lungs via capillaries
3) Lungs to left atria via pulmonary veins (oxygenated blood)
Systemic Circulation
-Left ventricle to organs via aorta (oxygenated)
-Organs remove oxygen via capillaries
-Organs to right atrium via superior + inferior vena cava (deoxygenated)
-Overall route: left ventricle to right atrium = systemic circulation
-Subdivisions/ sub routes:
cerebral = Brian
Hepatic = Liver
Coronary = Heart
Coronary Circulation (Visible Externally)
Look at diagram*
Fetal Circulation
- Fetus gets 02, nutrients from + expels wastes to mother’s blood
- Exchange site in the placenta
- Blood supplies in close together, but DO NOT mix
- Major difference compared to adult (diagram)
General Structure of blood vessels (Except Capillaries)
1) Tunica Externa - CT
2) Tunica Media
- Smooth muscle
- Elastic Fibers (CT)
3) Tunica Intima/ Interna
- Endothelium - simple squamous Epithelium
4) Lumen
- Contains blood (not a layer)
Arteries
- Carry Blood away from heart (does NOT refer to oxygen or deoxy)
- 2 Types
1) Elastic Arteries - Elastic CT in all 3 layers
- Largest arteries (near heart)
- E.g. Aorta
2) Muscular Arteries - A LOT of smooth muscle
- Most arteries
- E.g. Coronary artery
Arterioles
- Little Arteries
- Regulate blood flow + blood pressure
Capillaries
- Only tunica intimate - endothelium (one cell layer) + basement membrane
- Allow exchange of gases + nutrients
- Gaps allow limited fluid + solutes to leak out = interstitial fluid (ISF)
- Capillaries unite to form venules
Venules
Intima, thin media, thin externa
Veins
- Large lumen
- Valves prevent back flow of blood
- Thin media - less smooth muscle (Can collapse)
Blood Characteristics
- CT
- Higher viscosity than H2O
- 37 degree Celsius
- pH 7.35 - 7.45
- 4-6 L in an adult
Plasma (Matrix)
- = blood minus formed elements
- Composed of:
1) Water- 90%
2) Proteins - 8% - Albumin - control tissue water balance
- Fibrinogen - Clot formation
- Globulin - antibodies
3) Other solutes - 2% - Nutrients, hormones, wastes, electrolytes, gases
RBC - Erythrocytes
- Hematocrit = % of blood volume that is RBA (around 45%)
- Biconcave disc shape
- Anucleate when mature
- Life span 120 days
- Destroyed in the liver and spleen
- Contains Hemoglobin
Hemoglobin (Pigment Protein)
1) Heme = red pigment - contains iron (Fe)
- Attaches and transports 02
2) Globin = protein - Attaches and transports CO2
- Hemoglobin is broken down to heme and globin
- Heme is further broken down to bilirubin
- Fe2+ - recycled or stored (toxic, so always bound to protein)
- Globin to amino acids
WBC - Leukocytes
- Nucleated
- Life span varies - days to years
- Defend against disease
- 2 Types:
1) Granulocytes
2) Agranulocytes
Neutrophils
- Granulocyte
- Around 60%
- All. phagocytic (engulf + digest invaders)
- Kill bacteria
Eosinophils
- Granulocyte
- Around 3%
- Attacks parasites (E.g. Worms)
Basophils
- Granulocyte
- Around 1%
- Release: histamine (increases inflammation) and heparin (decrease local clotting)
Lymphocytes
- Agranulocytes
- Around 35% - immunity
- 2 Types:
1) T Lymphocytes - Kill infected/ diseased cells directly
2) B Lymphocytes - Become plasma cells - produce antibodies (=y globulin)
Monocytes
- Arganulocytes
- Around 5%
- Enter tissue + enlarge to become macrophages (phagocytic = “big eaters”)
Platelets
- Fragments of cells called megakaryocytes
- Involved in clotting
- Life span = around 10 days if not used for clotting
Hemopoiesis/ Hematopoiesis
- = Formation of blood cells
- All blood cells arise indirectly from hemocytoblast (=stem cells) cells in red bone marrow
- Red bone marrow in adult:
1) Axial Skeleton
2) Pelvic + Pectoral girdles
3) Proximal ends of humerus + femur
