The Circulatory System (CS) PDF

The Circulatory System (CS) 4 chambers of Heart: - Right & Left Atrium - Right & left ventri...

The Circulatory System (CS) 4 chambers of Heart: - Right & Left Atrium - Right & left ventricle a. Right ventricle: propels blood away from the heart to lungs (pulmonary circulation) b. Left ventricle: propels blood away from the heart to body (systemic circulation) c. Right atrium: receives blood from body d. Left atrium: receives blood from pulmonary Heart Wall Endocardium (Inner layer): FXN of Circulatory System: Epithelial tissue: Simple squamous epithelium - Transport blood Connective tissue: Loose connective tissue - Transport Oxygen & Carbon dioxide nutrient Myoelastic layer (Middle layer): compromises & metabolic waste smooth muscle fiber And connective tissue - Regulates temperature Subendocardial layer: ○ Has modified cardiac muscle tissues Functional Parts of CS AKA: Purkinje fibers 1. Blood vascular system FXN of purkinje fibers: - Blood vessels contribute in impulse - heart conducting system (contraction - blood of heart) 2. Lymph vascular system: collects tissue fluids ○ Emerge in myocardium a. Lymphatic capillaries: - Lymphatic vessels - Lymph nodes b. Lymphoid organs - Spleen - Thymus Components of CS 1. Heart 2. arteries and arterioles 3. Capillaries: smallest vessel 4. Venules and veins: transport blood to heart THE HEART 3 Layers of Heart wall 1. Endocardium 2. Myocardium 3. Epicardium 3 Layers of blood vessels 1. Tunica intima 2. Tunica media 3. Tunica adventitia Muscle type of Heart: Cardiac muscle Myocardium (middle layer): Epicardium Thickest layer: due to the strong force of More delicate layer compared to pericardial blood pumping (specifically: left ventricle) sac Directly in contact with heart’s surface Components: Epithelial tissue: Simple squamous Mostly cardiac muscle arranged in spiral Connective tissue: Loose pattern (responsible for twisting motion) ○ FXN of cardiac muscle: responsible for contraction of blood to pump out of the heart, thereafter, relaxes for the heart to refill. Fibrous skeleton (fibrous components): ○ Collagen fiber: FXN: - insulators carrying electric signal - structural support ○ Elastic fiber: Allows heart return to shape after it contracts Numerous blood vessels Pericardium (outer layer): Fluid-filled Double-walled (2 walls/membranes) Pericardial sac and epicardium are closed 1. Pericardial sac or parietal pericardium together & there is a pericardial fluid between - Composition: them a. Tough outer fibrous ○ FXN of pericardial fluid: reduces layer friction caused by pumping b. Thin serous lining of ○ Incase of heart disease/inflammation, epithelial tissue it will affect pericardial fluid as they will - FXN: anchors heart to aorta to increase and accumulate, build-up, vena cava compressing the heart, restricting 2. Epicardium or visceral pericardium pumping. Other structures in heart wall ❖ Dense fibrous connective tissue Characteristic: Found in cardiac skeleton Forms interventricular and interatrial septum Surround all valves of heart FXN: Anchor & support heart valves Provide firm point of insertion to cardiac muscle Helps in electrical insulation ❖ Cardiac conduction system (CCS): ❖ Purkinje fibers Generate & propagates electrical impulses Characteristic: Myocardial tissues that are component of Contributes to CCS CCS: Larger than cardiac fiber 1. Sinoatrial node (SA node) More glycogen 2. Atrioventricular node) (AV node) Lighter staining 3. Bundle of His (AV bundle) 4. Subendocardial conducting network Location: Beneath endocardium 1. Sinoatrial node (SA node) ❖ Systemic circuit Location: right atrial wall (near superior vena cava) Characteristic: FXN: initiates electrical impulse, These are the blood vessels spreads to atrium, stimulating (distributes blood) contraction. Components: “Natural pacemaker” - Arteries (carries blood away Characteristic: from heart) - Composed of cardiac muscles - Arteries (where exchange - Fewer myofibrils happens) - Intercalated discs - Veins (carry blood from heart) 2. Atrioventricular node (AV node) Layers of blood vessels: Location: floor of right atrium 1. Tunica intima FXN: receives impulse from SA node 2. Tunica media & delay them to ensure for complete 3. Tunica adventitia contraction from atrium before ventricles, then spreads to bundle of His Vessel tunics Characteristics: - Similar with SA node but Tunica intima smaller Innermost layer Composition: 3. Bundle of His (AV bundle) - Simple squamous epithelium Extends from AV node to (endothelium) which directly lines interventricular septum lumen of vessels, flat cells FXN: conducts electrical impulses to - Secretes fibrous components:: ventricles from AV node, then 1. Type II, IV, V collagen ventricles contract. 2. Laminin Two branches: bifurcate into 3. Endothelin ○ Right bundle: conduct impulse 4. Nitric oxide: to right ventricle FXN: component of ○ Left bundle: conduct impulse oxygen-dependent to left ventricle phagocytosis. 5. vWF 4. Subendocardial conducting network 6. Tissue factor Comprises specialized fibers: purkinje (5&6 function in coagulation) fiber 7. P-selection ○ FXN of purkinje fiber: rapidly - Posses: ACE, serotonin, transmit electrical impulse Tunica intima Artery Components: 3 major types: a. Subendothelial layer 1. Elastic arteries Composition: loose connective - (largest artery) tissue - AKA conducting artery b. Internal elastic lamina 2. Muscular arteries Composition: - AKA distributing artery - Elastin 3. Arterioles - Fenestrated (pores for - AKA smallest artery diffusion) - Well developed in Capillaries muscular arteries Smallest blood vessel: FXN: Separates tunica intima ○ 50 um (length) & media ○ 8-10 un (width) Structure: Tunica media - Single layer of squamous endothelial Thickest layer cell. Flat cells but nucleus is bulgy Components: - a. Concentric cell layer 3 types: - Helically arranged smooth 1. Continuous muscle 2. Fenestrated b. Fibrous elements: interspersed within 3. Sinusoidal smooth muscles - Elastic fibers Veins - Type III collagen 3 groups base on the diameter & wall - Proteoglycans thickness c. External elastic lamina 1. Small - More delicate 2. Medium - Only seen in larger muscular 3. Large arteries Venules: FXN: Separates tunica media & tunica 1. Post capillary venules adventitia 2. Large muscular venules Pericyte - Seen in capillaries & post-capillary Lymphatic vascular system vessels, because do not have tunica FXN: removes ECM (like lymph) from media interstitial spaces & return to cardiovascular - Therefore replaces tunica media system Components: Tunica adventitia - Lymph nodes Outermost layer - Vessels Blends in surrounding connective tissue 1. Lymphatic capillaries Composition: 2. Lymphatic vessels a. Dense irregular collagenous - Present in whole body connective tissue except CNS, internal b. Fibrous components: ear, epidermis, - Type I & III collagen fibers cartilage, & bones - Elastic fibers 3. Lymphatic ducts Vaso vasorum 1. Lymphatic capillaries “Vessels of vessel”: can enter vessel wall - Blind-ended, thin-walled FXN: furnish the muscular walls of the blood - Single-layer of attenuated endothelial vessels with blood supply cell More prevalent in the walls of veins than - Incomplete basal lamina arteries, veins contains more cells - No fenestration & no tight junctions - Bundles of lymphatic anchoring  filaments Lymphatic vessels Small & medium vessels - Closely spaced valves Large vessels - Resemble small vein - Lumina are larger & thinner walls - Thin layer of elastic fiber & smooth muscle cells Lymphatic ducts Similar to large veins FXN: Empty their contents into great veins of neck Shorty right lymphatic duct - Collects lymph from URQ Large thoracic duct - Collects lymph from the remainder of the body TUNICA INTIMA Endothelium & several layers of elastic & collagen fibers TUNICA MEDIA Layer of condensed elastic fiber; longitudinal & circular smooth muscle TUNICA ADVENTITIA Contains longitudinally oriented smooth muscle cells & collagen fibers Types of Location (organs) Characteristic Components arteries Elastic artery Aorta Yellow in fresh state, TUNICA INTIMA because of rich in Endothelium supported by Common carotid elastin fibers connective tissue with few artery fibroblast Subclavian artery Smooth muscle Common iliac artery Collagen Pulmonary artery Internal elastic laminae: appear thin Weibel-palade bodies: secretes vWF TUNICA MEDIA 40 (child) to 70 (adult) fenestrated membranes Smooth muscle cells (less abundant) interspersed between elastic membranes Extracellular matrix: - Chondroitin - Sulfate - Collagen - Reticular and elastin fiber External elastic lamina TUNICA ADVENTITIA Thin layer of fibroelastic connective tissue (loose) Fibroblasts Vasa vasorum (more abundant in veins Lymphatic vessels  Nerve fibers Muscular Brachial artery Thick tunica media TUNICA INTIMA artery with abundant smooth Thinner than elastic artery Ulnar artery muscle cells Subendothelial layer: few smooth Femoral artery muscle cells Renal artery Prominent internal elastic lamina Bifid: internal elastic lamina can be duplicated TUNICA MEDIA Predominant smooth muscle cells ○ Small muscular arteries: 3-4 layers ○ Large muscular arteries: 40 layers ○ Number of cell layers decreases as diameter of artery decreases External lamina: - envelopes each smooth muscle cells - Appears in several layers of thin elastic sheets Extracellular matrix: - Elastic fibers - Type III collagen - Chondroitin sulfate TUNICA ADVENTITIA Extracellular matrix: produced by fibroblasts - Elastic fibers & Collagen fibers (longitudinally arranged) - Ground substance (dermatan sulfate, and heparan sulfate)  Outer regions: - Vasa vasorum - Unmyelinated nerve ending Arterioles Arteries with diameter TUNICA INTIMA of