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Biology Chapter 42 Circulatory

by: Sophia Notetaker

Biology Chapter 42 Circulatory BIOC 0170

Marketplace > University of Pittsburgh > Biology > BIOC 0170 > Biology Chapter 42 Circulatory
Sophia Notetaker
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Biology Chapter 42 Circulatory
Foundation of Biology I
Barbara Barnhart
Class Notes
Biology, Chapter 42, circulatory
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This 18 page Class Notes was uploaded by Sophia Notetaker on Wednesday March 30, 2016. The Class Notes belongs to BIOC 0170 at University of Pittsburgh taught by Barbara Barnhart in Spring 2016. Since its upload, it has received 11 views. For similar materials see Foundation of Biology I in Biology at University of Pittsburgh.


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Date Created: 03/30/16
Chapter 42 – Circulation I. Overview A. Form relates to function Must exchange energy and materials with environment, so size and shape must adapt to function in that environment. Circulatory system is an adaptation of form that allows exchange with environment to occur at cellular level. B. Purpose of Circulatory System  To connect body cells that are in an aqueous environment to organs of exchange  To maintain Homeostasis  To carry blood to exchange – vessel to muscles and brain  Secreting – bringing out o Ex secreting sweat II. Circulatory Overview A. Invertebrates 1. 2-cell layer a. Cnidaria (jellyfish, sea anemone, hydra)  No need for a “real” circulatory system  Body is only 2 cell layers thick therefore material doesn't have far to travel  Have gastrovascular cavity which function for both digestion and circulation of nutrient throughout the body  Fluid bathes both inner and outer tissue layers which facilitates exchange of gases and cellular wastes 2. Multiple Cell Layers Ch 42 – Circulatory 1 - Multiple cell layers (more complex, need circulatory system) a. Components of Circulatory Systems 1) Circulatory fluid (blood) 2) Tubes (Interconnected blood vessels) 3) Muscular pump (Heart) b. Open Circulatory Systems  Arthoropods and most mollusks - insects  No distinction between circulatory fluid(hemolymph) and interstitial fluid (solution that surrounds the cells)  One or more hearts contract to pump hemolymph through vessels into sinuses  Chemical exchange occurs between hemolymph and body cells  Relaxation of hearts(s) draws hemolymph back through pores o Ex. Grasshopper c. Closed Circulatory Systems  Annelids and Cephalopods  Blood Kept inside of vessels separate from interstitial fluid(fluid in our body)  More efficient at delivering oxygen and nutrients to tissue Ch 42 – Circulatory 2  How will it works o One or more heart pump blood into large vessels that branch into smaller vessels which infiltrate organs to allow for chemical exchange.( constantly exchanging nutrients) o Chemical exchange occurs between blood and the interstitial fluid as well as between interstitial fluid and body cells  Nutrients to the cell B. Vertebrates ( closed system  cardiovascular system) 1. General Structure – has blood vessels and a 2 or 4 chambered heart a. Arteries (AWAY)  Carry blood away from the heart  Thick so that it can can withstand great pressure b. Arterioles  Arteries branch into arterioles within organs  Small vessels that convey blood to capillaries c. Capillaries  Very thinned walled  This is the site of chemical exchange between blood and interstitial fluid  It will converge into venules o Small vessels that does all the exchanging of nutrients d. Venules  It will converge into veins  Small- connect to the capillaries e. Veins  Carry blood back to the heart  They have valves – backward. Low blood pressure Ch 42 – Circulatory 3 f. Remember arteries and veins are distinguished by direction of blood flow - Arteries – away from heart to capillaries - Veins – to heart from capillaries - Higher metabolic rate = more complex circulatory system. Ventricle and atrium are chambers in the heart. 2. Variation between organisms a. Fish  2 chambered heart  1 ventricle and 1 atrium  Pathway of blood flow o Ventricle pumps to the gill( gets oxygen and gets rid of carbon dioxide) o From the gills to other parts of the body o Other parts of the body to atrium o Atrium moves blood down to the ventricle o Never have oxygenated blood, always deoxygenate blood b. Amphibians Ch 42 – Circulatory 4  3 chambered heart  1 ventricle and 2 atria  Mixing of oxygen rich and oxygen poor blood in ventricle before ventricle pumps blood to both: o Lungs (oxygen poor blood) o Other body parts (oxygen rich blood)  Double circulation o One circuit to lung (pulmonary) o One circuit to body (systemic) blue – vein red - artery c. Reptiles  3 chambered heart  1 ventricle and 2 atria  Ventricle partially divided by a septum( septum pierce)  Double circulation Ch 42 – Circulatory 5 d. Mammals and Birds  4 chambered heart ( 2 ventricles and 2 atria)  Left side chambers get oxygen rich blood from lungs  Right side chambers get oxygen poor blood from body REMEMBER: Form relates to function Ch 42 – Circulatory 6  endotherms require 10 times the energy as ectotherms of same size  circulatory system must deliver 10 times the oxygen and nutrients to tissues therefore need a large, powerful 4-chambered heart III. Human Circulatory System ( KNOW THIS FOR THE EXAM) A. Pathway of the heart 1. Blood from body enters right atrium via vena cavae(deoxygenated)  Superior – upper body  Inferior – lower body 2. Blood goes to right ventricle through the atrial ventricular valve (tricuspid) 3. Blood pumps out of the right ventricle through a semilunar valve via the pulmonary artery to the lungs. Gets oxygenate and gets rid of carbon dioxide 4. Blood returns from lungs and enter from left atrium via the pulmonary vein (oxygenated) 5. Blood goes to the left ventricle through another atrioventricular valve (bicuspid/mitral) 6.Blood is pumped out of the left ventricle through another semilunar valve via the aorta 7. Blood is delivered to body tissues – unloads oxygen and picks up carbon dioxide 8. Blood from body returns to right atrium Left side is stronger and thicker and right side is thinner Ch 42 – Circulatory 7 Pulmanary artery is the only artery that will carry deoxygenated blood. – cuz it going away Pulmaonary vein is the only vein that will carry oxygenated blood because it just picked up from the lungs and it is going to heart. There are valves ( opening and closing) in our vein so it can push it up. B. How Heart Works 1. Cardiac Cycle  Rhythmic contractions and relaxation of heart o Systole – contraction  Talking blood pressure o Diastole - relaxation 2. Cardiac Output Ch 42 – Circulatory 8  Volume of blood pumped into systemic circuit (body) per minute o heart rate – beats/min pulse o stroke volume – amount of blood pumped by left ventricle 3. Defects  Heart Murmur o Valves do not close completely o Blood flows backward o Atrioventricular valve (between atrium and ventricle) ( tricuspid and bicuspid) o Semilunar valve (between ventricle and artery) C. Maintaining Heartbeat 1. Muscle  Cardiac muscle is self- excitable  It can contract on it own 2. Pacemaker  For humans it is the sinoatrial node (SA node)  Sets the rate/timing of the cardiac muscle contraction o Generates electrical impulse o Impulse spreads through atria and to the AV node o AV node sends the impulse to ventricles which contracts through movement of Purkinje Fibers  In hospital eletrodes on skin to keep track of heart rate  Detects electrical impulse from SA node  Electrocardiogram  Pacemaker good control center by affects by: o Hormones, Body temperature, Exercise  -It creates electrical impulses that spread throughout the heart and stimulating heart/muscle contraction. That sets the pace. – that why we are pumping. Ch 42 – Circulatory 9 IV. Movement of Blood through Circulatory System A. Blood Vessels 1. 3-layers of tissue a. outside – connective tissue (flexible)  Contains elastic fibers) b. middle – smooth muscle c. inside – endothelium  Single layer of flattened epithelial cells  Smooth surface therefore low resistance to flow 2. Arteries  Thick walls because blood pumped out of heart at high pressure to withstand it  Have elastic recoil to help maintain blood pressure  Nerve impulses and hormones will dilate or constrict the smooth muscle this controlling blood flow o Our arteries are stretchy 3. Veins  Thinner walls  Blood is pushed through by contraction of skeletal muscle ( push the blood up, back to the heart)  Veins have valves to keep blood from flowing backwards due to the low pressure  Veins have low pressure Ch 42 – Circulatory 10 B. Blood Flow Rate 1. Arteries – very fast 2. Veins - slow 3. Capillaries  Slowest due to high resistance  Large cross-sectional area  Makes sense since capillaries are point of exchange between blood and interstitial fluid o Gas exchange is taking place C. Blood Pressure ( balloon )  Blood pushing on inner wall of vessel 1. Systolic Pressure Ch 42 – Circulatory 11 a. The highest pressure in arteries during ventricular systole (contraction) b. AV valve closing c. Listening for the contraction where the AV valve is closing 2. Diastolic Pressure a. The pressure in arteries during diastole (relaxation) b. Semilunar valve closing D. Function of Capillaries 1. Overview  Don't always have blood flowing through all capillaries (5-10% of body’s capillaries have blood flowing through them)  Remember though that we have many capillaries, so each tissue/ organ always has an ample blood supply  Brain, heart, kidneys, and liver are usually filled to capacity  Other organs/ tissue tend to vary o After eat, blood supply supply increased in the digestive track o Body is pumping more blood to the digestive system o More blood = more nutrients 2. Regulatory Function of Capillaries  Capillaries lack smooth muscle ( they have endotheliilum) a. Two Mechanisms 1) Contraction of smooth muscle of arteriole Ch 42 – Circulatory 12  This reduces the diameter of arteriole which decreases blood flow to the capillaries  Arteriole pushes the blood to the capillaries 2) Precapillary sphincters are rings of smooth muscle located at entrance of capillary beds - automatically pinches it  They receive signals(nerve impulses, hormones, etc) which causes them to open or close therefore regulation blood flow b – when food is digestive 3. True Function of Capillaries a. Exchange between blood and interstitial fluid b. Driven by pressure o Blood pressure on artery side of capillary(arteriole) is higher therefore pushes fluid out o But blood proteins that don't leave ( bcuz they are too large and they are going to stay in the blood. Smaller materials will get out) create osmotic pressure between blood and interstitial fluid therefore causing fluid to move back in Ch 42 – Circulatory 13 o Arteriole side – blood pressure high, osmotic pressure lower o Venule side – blood pressure little lower osmotic pressure almost the same o Blood pressure will decrease because we are going toward the heart. V. Blood = Connective Tissue  It is a connective tissue because there are many cell type suspended in plasma o 45% of blood volume = cells o 55% is plasma A. Plasma 1. Components a. 90% Water (solvent) b. Electrolytes (dissolves ions/salts) o Some are buffers (pH 7.4) o Affects composition of the interstitial fluid  Whatever is in the blood, it goes to the interstitial fluid o Must be kept in a narrow concentration range  Everything need to be in a set range. Ch 42 – Circulatory 14 c. Plasma proteins o Buffers again pH changes o Help maintain balance between blood and interstitial fluid o Contributes to viscosity (thickness)  (milkshake is thicker than water) o Responsible for  Immunity, Blood clotting, Transport lipids B. Cellular Components 1. Erythrocytes  Most numerous blood cell ( donut looking cell)  Bioconcave (round and have a dip in the center) disks that lack nuclei  Main function is to transport oxygen o Due to hemoglobin (iron contain molecule that binds 4 oxygen molecules) o Each erythrocyte has 250 million hemoglobin (1 blood cell) molecules 2. Leukocytes (white blood cells)  White blood cell count changes when fighting infection  Found also in interstitial fluid and lymphatic system  Main function is to fight infection (immunity)  Types of leukocytes o Basophils o Lymphocytes o Eosinophils o Neutrophils o Monocytes 3. Platelets - form out scaps when we are hurt.  Cytoplasmic fragments of bone marrow cells  Function in blood clotting Ch 42 – Circulatory 15 C. Blood Clotting 1. Blood vessel damaged  Exposes proteins that attracts platelets 2. Platelets Release clotting factors that triggers the making of thrombin(enzyme)  Also makes nearby platelets sticky  Sticky platelets form an emergency plug 3. Thrombin is an enzyme that will convert fibrogen to fibrin(cloth- hard) 4. Fibrin aggregates into threads and form a fibrin clot that reinforces the platelet plug D. How these cells are made a. Made from stem cells – (first made) i. Located in red marrow of bones (ribs, vertebrae sternum, and pelvis) ii. Stem cells will form myeloid and lymphoid cell lineages Ch 42 – Circulatory 16 VI. When Parts of System Fails A. Types of Cardiovascular Disease a. 1 – Atherosclerosis – gets from chicken nuggets i. Cholesterol plaque build up in arteries (hardening of the arteries) ii. LDLs – below density – bad cholesterol b. 2 - Hypertension i. High blood pressure increases the change of atherosclerosis, heart attack and stroke due to damage of the endothelium lining which promotes plaque formation. Ch 42 – Circulatory 17 1. The endothelium lining Is smooth, so if it is damage, then plaque forms c. 3 - Heart Attack ( myocardial infarction) i. Damage or death of cardiac muscle tissue because of blockage of coronary artery(s) ii. Blockage deprives oxygen d. 4- Stroke i. Nerve tissue in the brain dies due to lack of oxygen ii. Usually the result is from rupture of blockage or arteries in the head. Ch 42 – Circulatory 18


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