Module 10: The Circulatory System PDF
Document Details
Uploaded by LucidHelium
Tags
Related
- ICSE Class 10 Biology - The Circulatory System PDF
- Anatomy and Physiology Unit 4 - Circulatory & Lymphatic System PDF
- Human Anatomy and Physiology With Pathophysiology - Module 6 - PDF
- Year 8 Biology Lesson 6 - Circulatory System PDF
- Biology Ch 6 Circulatory System PDF
- Anatomy of the Circulatory System (PDF)
Summary
This document describes the circulatory system, including diffusion, gastrovascular cavities, and different types of circulatory systems. It also explains the organization of vertebrate circulatory systems and the three main types of blood vessels.
Full Transcript
MODULE 10: THE CIRCULATORY SYSTEM losed Circulatory System: Blood is confined to C vessels and is dist...
MODULE 10: THE CIRCULATORY SYSTEM losed Circulatory System: Blood is confined to C vessels and is distinct from the interstitial fluid. irculatorysystemslinkexchangesurfaceswithcells C Annelids, cephalopods, and vertebrates throughout the body iffusion: It is a process by which small molecules D canmovebetweencellsandtheirsurroundings(O2 and CO2). It is only efficientoversmalldistancesbecausethe time it takestodiffuseisproportionaltothesquare of the distance. In small or thin animals, cells can exchange ORGANIZATION OF VERTEBRATE CIRCULATORY materials directly with the surrounding medium. SYSTEMS Thecardiovascular system: In most animals, cells exchange materials with the Closed circulatory system in humans and environment via a fluid-filled circulatory system. other vertebrates Blood flow is one wayin these vessels ASTROVASCULAR CAVITIES G It functions in both digestion and distribution of There arethree main types of blood vessels: substancesthroughout the body. rteries: These branch into arterioles and carry A T he body wall that encloses the gastrovascular blood away from the heart to capillaries. cavity isonly two cells thick. apillaries: Sites of chemical exchange C S ome cnidarians have elaborate gastrovascular between the blood and interstitial fluid. cavities. Veins:Return blood from capillaries to the heart. F latworms have a gastrovascular cavity and aflat bodythat minimizes diffusion distances. rteriesandveinsaredistinguishedbythedirection A of blood flow, not by O2 content. Some animals lack a circulatory system. Vertebrate hearts containtwo or more chambers. T HE CIRCULATORY SYSTEMS Blood enters through an atrium and is It connects the fluid that surrounds cells with the pumped out through a ventricle. organsthatexchangegasses,absorbnutrients,and dispose of waste. circulatory system has: (1) circulatory fluid, (2) A interconnecting vessels, and (3) a pump, which is the heart. pen Circulatory System: Circulatory fluid called O hemolymphbathes the organs directly. It is found in insects, other arthropods, and molluscs. 8 TYPES OF CIRCULATION ingle Circulation: Blood leaving the heart passes S through two capillary bedsbefore returning. ony fishes, rays,andsharkshavesinglecirculation B with atwo-chambered heart. volutionary Variation in Double Circulation E Some vertebrates with double circulation are intermittent breathers. Amphibians and many reptiles may pass long periods without gas exchange, or relying on gas exchange from another tissue, usually the skin. ouble Circulation: Oxygen-poor and Oxygen-rich D blood are pumped separately from the right and Frogs and other amphibians: left sides of the heart. Have a three-chambered heart: two atria and one ventricle It maintains higher blood pressure in the organs The ventricle pumps blood into a forked than it does in single circulation. artery that splits the ventricle’s output into the pulmocutaneous circuit and the It is found in amphibians, reptiles, and mammals. systemic circuit. Whenunderwater,bloodflowtothelungsis Inamphibians: nearly shut off. Oxygen-poor blood flows through a pulmocutaneous circuit to pick up oxygen through the lungs and skin. Oxygen-rich blood delivers oxygen through the systemic circuit. 9 Mammals & birds: Endotherms that require more O2 than ectotherms Separation of deoxygenated and oxygenated blood Septum is fully formed. Have a four-chambered heart; two atria and two ventricles The left side of the heart pumps and receivesonly oxygen-rich blood. The right side of the heart receives and pumpsonly oxygen-poor blood. Turtles, snakes, & lizards: Have a three-chambered h eart: two atria and one ventricle It is partially divided by an incomplete septum. MAMMALIAN CIRCULATION Alligators, caimans, & other crocodilians: A septum divides the ventricles but pulmonary and systemic circuits connect where the arteries exitthe heart. 10 ( 1) Therightventriclepumpsbloodtothelungsvia T he Atria (Atrium): It has thin walls. It serves as pulmonary arteries. collection chambers for blood returning to the heart. ( 2) In the lungs, the blood loads O2 and unloads CO2. T he Ventricles: It has thicker walls and contracts much more forcefully. It pushes blood out of the ( 3)Oxygen-richbloodfromlungsenterstheheartat heart to the heart. theleftatriumviapulmonaryveins.(4)Itispumped through the aorta to the body tissues by the left T he Cardiac Cycle ventricle. The heart contracts and relaxes in a rhythmic cycle. ( 5) The aorta provides blood to the heart through Systole:Contraction or pumping phase thecoronary arteries. Diastole:Relaxation or filling phase ( 9 & 10)Bloodreturnstoheartthroughthesuperior vena cava (from head, neck, & forelimbs) and Heart rate:Number of of beats per minute inferior vena cava(from trunk & hind limbs). The SVC and IVC flow into theright atrium. In summary: Oxygenated Blood Right ventricle (deoxygenated) → Lungs → Pulmonary Veins → Left Atrium → Left Ventricle → Aorta → Body Tissues & Heart Deoxygenated Blood lood from head, neck, & forelimbs → Superior B Vena Cava (SVC) → Right Atrium → Heart (right ventricle) ← Right Atrium ← Inferior Vena Cava (IVC) ← Blood from trunk & hind limbs THE MAMMALIAN HEART T here are four valves in the heart that prevent backflow of bloodin the heart. Atrioventricular Valves: between atrium & ventricles Semilunar Valves: between rightventricle& pulmonaryartery(rightside),leftventricle& aorta (left side) aintaining the Heart’s Rhythmic Beat M Cardiac muscle cells are autorhythmic, meaning they contract without any signal from the nervous system. 11 inoatrial (SA) Node: Also called pacemaker, sets S the rate and timing at which cardiac musclecells contract. lectrocardiogram (ECG or EKG): It can record E impulses that travel during the cardiac cycle. LOOD COMPOSITION & FUNCTION B Blood is a connective tissue consisting of several kinds of cells suspended in a liquid matrix called plasma. lasma: Itcontainsinorganicsaltsasdissolvedions, P sometimes calledelectrolytes. lasma proteins influence blood pH and help P maintain osmotic balance between andinterstitial fluid. articularplasmaproteinsfunctioninlipidtransport, P immunity, and blood clotting. rythrocytes (Red Blood Cells): It is the most E numerousbloodcell.ItcontainsHemoglobin(Hgb), theiron-containing protein that transports O2. In mammals, mature RBCs lack nuclei and mitochondria. latelets: Fragments of cells and function in blood P clotting. L eukocytes (White Blood Cells): It is mainly for defense either by phagocytizing bacteria and debris (rest of WBCs) or by mounting immune ellularelementsoccupyabout45%ofthevolume C responses against foreignsubstances(lymphocytes of blood. only). It is found both in and outside of the circulatory system. 12 T here are five major types: (1) monocytes, (2) neutrophils, (3) basophils, (4) eosinophils, and (5) lymphocytes. BLOOD CLOTTING (COAGULATION) It is theformation of a solid clot from liquid blood. cascadeofreactionsconvertsinactivefibrinogen A to fibrin, forming a clot. blood clotformedwithinabloodvesseliscalled A athrombusand can block blood flow. 1: The enzymatic cascade performed by clotting # factors (platelets, damaged cells, & plasma) initiates theconversion of prothrombin to thrombin. #2:Thrombin converts fibrinogen to fibrin. #3:Clot formation is initiated. T his is a positive feedback loop. This is due to the enzymatic cascade initiation of the conversion of prothrombin to thrombin. Thrombin then also increases the stimulus of the enzymatic cascade. 13
