Body Fluids and Circulation PDF

Body Fluids and Circulation © 2022, Aakash BYJU'S. All rights reserved reserved. Key Takeaway Circulatory system Types of circulatory system Circulation 1 2 3 4 Stimulation of heart muscle contraction © 2022, Aakash BYJU'S. All rights reserved. Cardiac cycle 5 6 Heart diseases Human circulatory syst...

Body Fluids and Circulation © 2022, Aakash BYJU'S. All rights reserved reserved. Key Takeaway Circulatory system Types of circulatory system Circulation 1 2 3 4 Stimulation of heart muscle contraction © 2022, Aakash BYJU'S. All rights reserved. Cardiac cycle 5 6 Heart diseases Human circulatory system 7 Electrocardiogram: ECG 8 Components of blood 9 10 Functions of blood 13 Summary​ © 2022, Aakash BYJU'S. All rights reserved. Coagulation of blood 11 12 Lymph Regulation of cardiac activity Blood grouping Circulatory System It is also known as the cardiovascular system. Its primary role is to provide nutrients, gases, and hormones to different parts of the body. It also transports O2 and CO2. It collects all the waste from different parts of the body and delivers it to the excretory system. © 2022, Aakash BYJU'S. All rights reserved. Intestine (Digestive system) Nutrients and water Lungs (Respiratory system) O2 Body CO2 Waste like urea Kidneys (Excretory system) Types of Circulatory System Types of circulatory systems in animals Open Closed  The heart pumps the circulatory fluid known as hemolymph through the vessels into open spaces or body cavities.  The blood pumped by the heart is always circulated through a closed network of blood vessels.  The hemolymph returns to the heart via small pores known as ostia.  The flow of fluid through this system can be regulated. Heart Heart Blood vessels Blood vessels Body cells Body cells © 2022, Aakash BYJU'S. All rights reserved. Types of Circulatory System  Example: Arthropods, molluscs  Example: Annelids, chordates Heart Heart Hemolymph in sinuses surrounding organs Blood Blood vessels Ostia Heart Arthropod © 2022, Aakash BYJU'S. All rights reserved. Annelid Human Circulatory System Human circulatory system Circulating fluid Heart Blood vessels © 2022, Aakash BYJU'S. All rights reserved. Human Circulatory System Circulating fluids Blood Lymph  It is a fluid connective tissue.  It is a colourless fluid.  It transports oxygen, nutrients, antibodies, etc.  It carries immune cells, nutrients, etc. Human heart  It is a muscular organ.  It is derived from mesodermal tissue.  It is located between the lungs in the thoracic cavity.  It is roughly the size of a clenched fist and 12 cm long. 12 cm Size © 2022, Aakash BYJU'S. All rights reserved. Human Circulatory System Layers in the heart Pericardium (Around heart) It is a protective covering around the heart, and the space between pericardium is filled with pericardial fluid. Pericardium Pericardial fluid Myocardium (Muscle heart) It is a muscular wall of heart. It contracts to pump blood out of the heart and then relaxes as the heart refills with returning blood. Endocardium (Inner heart) It remains in contact with blood.​.. © 2022, Aakash BYJU'S. All rights reserved. Pericardium Myocardium Endocardium Human Circulatory System Structure of a human heart Atria  These are the small upper chambers. Superior vena cava Carries oxygen poor-blood from the upper parts of the body Right atrium Receives deoxygenated blood from the body Interior vena cava Carries oxygen poor-blood from the lower parts of the body © 2022, Aakash BYJU'S. All rights reserved. Human heart consists of four chambers:  Right and left atria  Right and left ventricles Pulmonary vein Blood enters the left atrium through the four pulmonary vein openings Left atrium Receives oxygenated blood from the lungs Human Circulatory System Ventricles These are the large lower chambers. Aorta Pumps oxygenated blood to the rest of the body Pulmonary semilunar valve Guards the opening of the right ventricle to the pulmonary artery Right ventricle Receives deoxygenated blood from the right atrium and then pumps blood into the pulmonary artery or pulmonary trunk © 2022, Aakash BYJU'S. All rights reserved. Pulmonary artery Pumps deoxygenated blood to the lungs Aortic semilunar valve Guards the opening of the left ventricle to the aorta Left ventricle Receives oxygenated blood from the left atrium and then pumps blood into the aorta which then supplies to the whole body Human Circulatory System Right ventricle Left ventricle Comprises of thin wall Comprises of thick wall Receives deoxygenated blood from the right atrium Receives oxygenated blood from the left atrium Pumps blood to lungs through the pulmonary trunk Pumps blood to the whole body through the aorta Left ventricle  Right ventricle © 2022, Aakash BYJU'S. All rights reserved. The left ventricle is larger and thicker than the right ventricle o Because the left ventricle has to pump blood to the whole body through aorta. Human Circulatory System Septum  The septum’s primary function in the heart is to isolate the two sides of the heart. Atria Atrioventricular septum Atria and ventricles on the same side are separated by atrioventricular septum Interatrial septum Separates left and right atrium Interventricular septum Separates left and right ventricles Ventricles © 2022, Aakash BYJU'S. All rights reserved. Human Circulatory System Valves    Valves are flaps of fibrous tissues located in the cardiac chambers. They ensure that blood flows in a single direction (unidirectional). Flaps also prevent blood from flowing backwards. Tricuspid valve   Bicuspid or mitral valve It has three flaps. It guards the opening between right atrium and right ventricle. © 2022, Aakash BYJU'S. All rights reserved. Chordae tendinae Papillary muscles   They regulate the opening and closing of bicuspid and tricuspid valves. It has two flaps. It guards the passage from left atrium to left ventricle. Human Circulatory System Blood vessels Arteries Veins Capillaries Arteriole Artery Heart Arteries Carry blood Different parts of body  Pinkish or bright red in colour as they carry oxygenated blood.  Blood flows with a high pressure. © 2022, Aakash BYJU'S. All rights reserved. Different Veins parts of Carry blood body  Heart Bluish or deep red in colour as they carry deoxygenated blood. Venule Vein  Arteries branch out into arterioles and veins into venules.  These arterioles and venules branch out into smaller, thinner blood vessels known as capillaries.  They allow exchange of gases and other materials.  They act as a connection between arteries and veins. Human Circulatory System Layers of arteries and veins © 2022, Aakash BYJU'S. All rights reserved. Tunica intima Squamous endothelium Tunica media Smooth muscle and elastic fibres Tunica externa Fibrous connective tissue with collagen fibres Human Circulatory System Types of blood circulation Single circulation   Seen in 2-chambered heart   Example: Fish Contains one atrium and one ventricle The deoxygenated blood is pumped from heart to gills. © 2022, Aakash BYJU'S. All rights reserved. Incomplete double circulation    Seen in 3-chambered heart Contains two atria and one ventricle Examples: Amphibians and reptiles (except crocodile)  The left atrium receives oxygenated blood from gills/skin/lungs and the right atrium receives deoxygenated blood from the body.  They inter-mix in a single ventricle, which pumps it out to gills/skin/lungs and to different parts of body, thus it is known as incomplete circulation.  Blood passes through the heart twice, hence known as double circulation.  It is inefficient when compared to complete double circulation. Complete double circulation   Seen in 4-chambered heart   Examples: Birds and mammals  The right atrium receives deoxygenated blood from the body and passes it to the right ventricle.  Ventricles pump out the blood without mixing up.  Two separate circulatory pathways are present, hence known as complete double circulation. Contains two atria and two ventricles The left atrium receives oxygenated blood from lungs and passes it to the left ventricle. Human Circulatory System Single circulation Incomplete double circulation Complete double circulation Lungs Gills Heart Right atrium Right atrium Ventricle Various body parts © 2022, Aakash BYJU'S. All rights reserved. Left atrium Left atrium Right ventricle Various body parts Left ventricle Circulation Systemic circulation Types of circulation Pulmonary circulation Hepatic circulation Coronary circulation © 2022, Aakash BYJU'S. All rights reserved. Double Circulation   It is known as double circulation because the blood passes through the heart twice. The separation of oxygenated and deoxygenated blood allows for a more efficient supply of oxygen to the body. Pulmonary artery Right ventricle to lungs Carries deoxygenated blood Tricuspid valve Right atrium to right ventricle Vena cava Tissues to right atrium Carries deoxygenated blood © 2022, Aakash BYJU'S. All rights reserved. Lungs Deoxygenated blood gets converted to oxygenated blood Pulmonary veins Lungs to left atrium Carry oxygenated blood Bicuspid valve Left atrium to left ventricle Aorta Left ventricle to tissues Carries oxygenated blood Tissues Oxygenated blood gets converted to deoxygenated blood Systemic Circulation The upper and the lower body have different supplies. o At every organ and tissue, oxygenated blood is converted to deoxygenated blood. o All deoxygenated blood returns to the heart. o The oxygenated blood entering the aorta is carried by a network of arteries, arterioles, and capillaries to the tissues. o From the tissues, the deoxygenated blood is collected by a system of venules, veins, and vena cava and emptied into the right atrium. o This is systemic circulation. o The lungs are not involved in this process. Right atrium Right ventricle Vena cava (Veins) © 2022, Aakash BYJU'S. All rights reserved. Left atrium Systemic circulation Tissues Left ventricle Aorta (Arteries) Systemic Circulation Heart Oxygenated blood Tissues Aorta (Arteries, arterioles, capillaries) Functions of systemic circulation Provides: o Nutrients o Oxygen o Other essential substances to the tissues  Deoxygenated blood Tissues Heart Vena cava (Capillaries, venules, veins) © 2022, Aakash BYJU'S. All rights reserved. Removes: o Carbon dioxide o Other harmful substances from the tissues Pulmonary Circulation Deoxygenated blood is pumped by the right ventricle into the pulmonary artery. The deoxygenated blood pumped into the pulmonary artery is passed on to the lungs and from there, the oxygenated blood is carried by the pulmonary veins into the left atrium. This pathway constitutes the pulmonary circulation. Before birth, the major portion of blood from the right side bypasses the pulmonary circulation (no air in lungs) via foramen ovale (between right and left auricle) and ductus arteriosus. This bypass becomes non-functional after the birth. If the hole fails to seal, then it is said that there is a hole in the heart. Lungs Pulmonary artery Pulmonary circulation Right ventricle © 2022, Aakash BYJU'S. All rights reserved. Pulmonary vein Left atrium Ductus arteriosus Hepatic Circulation      A unique vascular (circulatory) connection between the digestive tract and the liver is known as the hepatic portal system. The liver receives oxygenated blood from the hepatic artery. It also receives blood from the hepatic portal vein. The hepatic portal vein carries blood from the intestine and parts of the digestive system to the liver before it is delivered to the systemic circulation. This blood contains nutrients and toxins extracted from digested contents, which the liver stores and detoxifies respectively. Oxygenated blood Heart Liver Hepatic artery Deoxygenated blood Intestine Liver Hepatic portal vein © 2022, Aakash BYJU'S. All rights reserved. Coronary Circulation  Coronary arteries supply oxygenated blood to the heart muscle.  Cardiac veins drain the deoxygenated blood from the heart muscle.  The heart muscle, like all the tissues in our body, requires energy and it takes energy from the oxygen and nutrients from the coronary artery. Coronary arteries and veins Coronary circulation © 2022, Aakash BYJU'S. All rights reserved. Cardiac Cycle  It comprises the complete relaxation and contraction of both the atria and ventricles.  It consists of three stages: o Joint diastole o Atrial systole o Ventricular systole Duration of one cardiac cycle is 0.8 seconds. 1. Joint diastole Early joint diastole © 2022, Aakash BYJU'S. All rights reserved. Late joint diastole Cardiac Cycle 1. Joint diastole Early joint diastole Ventricles Diastole (Relaxed) Atria Diastole (Relaxed) Atrioventricular valves(Closed) Semilunar valves- (Closed)  All the chambers of the heart are relaxed and the blood enters the heart chambers through the veins.  The oxygenated blood flows through the pulmonary veins and the deoxygenated blood flows through the superior and inferior vena cava into the left and the right atria, respectively. © 2022, Aakash BYJU'S. All rights reserved. Late joint diastole Ventricles Diastole (Relaxed) Atria Diastole (Relaxed) Atrioventricular valves– (Open) Semilunar valves- (Closed)  The tricuspid and bicuspid valves are pushed open by the pressure in the atria exerted by the blood that was being emptied into them by the veins. ​  The blood moves from the atria to the ventricles.​ Cardiac Cycle 2. Atrial systole Ventricles Diastole (Relaxed) Atria Systole (Contract) Atrioventricular valves– (Open) Semilunar valves- (Closed) As the atria contract, the rest of the blood is pumped from the atria to the ventricles.​ © 2022, Aakash BYJU'S. All rights reserved. Cardiac Cycle 3. Ventricular systole Early ventricular systole Late ventricular systole Ventricles systole (Contract) Atria diastole (Relaxed) Ventricle systole (Contract) Atria diastole (Relaxed) Atrioventricular valves(Closed) Semilunar valves- (Closed) Atrioventricular valves(Closed) Semilunar valves (Open) Ventricular systole increases the ventricular pressure, causing the closure of the tricuspid and bicuspid valves due to the attempted backflow of blood into the atria. © 2022, Aakash BYJU'S. All rights reserved. As the ventricular pressure increases, the semilunar valves guarding the pulmonary artery (right side) and the aorta (left side) are forced open, allowing the blood in the ventricles to flow through these vessels into the circulatory pathways. Cardiac Cycle Early Blood enters the atria through the veins. Late The AV valves are open. Some blood enters the ventricles. Joint diastole Atrial systole The rest of blood is pumped from the atria to the ventricles. Early Ventricular contraction causes the AV valves to close. Late Ventricular contraction causes the semilunar valves to open. The blood is pumped into the arteries. Ventricular systole © 2022, Aakash BYJU'S. All rights reserved. Heartbeat, Heart Sounds and Stroke Volume Heartbeat     A heartbeat is the rhythmic contraction and relaxation of the heart chambers. Our heart normally beats 70-75 times in a minute (average 72 beats per min). This is called heart rate. The contraction of the heart chambers is known as systole. The relaxation of the heart chambers is known as diastole. Stroke volume  Each ventricle pumps out approximately 70 mL of blood, which is the stroke volume. Output Heart sound     Due to the closure of the valves in the heart, we hear heart sounds. During each cardiac cycle, two sounds are produced. The closing of atrioventricular valves causes the first sound, which is lub. The closing of semilunar valves causes the second sound, which is dub. © 2022, Aakash BYJU'S. All rights reserved. 70 ml 100 ml graduate Ventricular ejection Cardiac Output It can be defined as the volume of blood pumped out by each ventricle per minute. Heart rate is the rhythmic contraction and relaxation of the heart chambers. Cardiac output = Heart rate x Stroke volume 72 × 70 = 5,040 Approximately, 5,000 ml or 5 liters of blood is pumped every minute. © 2022, Aakash BYJU'S. All rights reserved. Blood Pressure Blood pressure is the force that blood exerts against the walls of the blood vessels. Blood pressure drives the flow of blood from the heart through the arteries and arterioles to the capillary beds due to the pumping of the heart. It is only calculated in arteries because the blood pressure in the arteries is much higher than in the veins. It is due to receiving blood from the heart after contraction and also due to their contractile capacity. Systolic pressure refers to the maximum pressure within the large arteries when the heart muscle contracts to propel blood through the body. Diastolic pressure describes the lowest pressure within the large arteries when the heart muscles relax between two beats. Lungs Artery Pressure exerted by blood Heart Arteriole and capillaries (body) How is blood pressure measured? Sphygmomanometer: Also known as the blood pressure monitor It is a device for measuring blood pressure. In this measurement, 120 mm Hg (millimetres of mercury pressure) is the systolic pressure or pumping pressure, and 80 mm Hg is the diastolic pressure or resting pressure. © 2022, Aakash BYJU'S. All rights reserved. Sphygmomanometer Hypertension  The levels of arterial pressure put mechanical stress on the arterial walls.  Higher pressures increase heart workload and the progression of unhealthy tissue growth that develops within the walls of the arteries.  Higher the pressure, more is the stress on the heart. The heart muscle tends to thicken, enlarge, and become weaker over time.  If repeated checks of an individual’s blood pressure has a reading of 140/90 or higher, it indicates hypertension.  High blood pressure leads to heart diseases and also affects vital organs like the brain and the kidneys.  It can harm the heart, the brain, the kidneys, and the eyes. Causes of hypertension Increased levels of cholesterol Smoking © 2022, Aakash BYJU'S. All rights reserved. Stress Kidney disorder Stimulation of Heart Muscle Contraction Sinoatrial node  SA Node present at the upper right corner of right atrium is called as pacemaker, a contracting wave originates from SAN and spreads to other parts of the heart. Atrioventricular node  AV node present at the lower left corner of the right atrium transfers the contraction wave via atrio-ventricular septa to come out at interventricular septum as bundle of His and immediately divides into a right and left bundle. © 2022, Aakash BYJU'S. All rights reserved. Nodal tissue Regulates the heartbeat intrinsically Bundle of His  It conducts action potential.  It helps in contraction of ventricles. Sinoatrial node (SA Node) Bundle of His Purkinje fibres  Atrioventricular node (AV Node) Purkinje fibres A bundle of nodal fibres that help in ventricular contraction Stimulation of Heart Muscle Contraction  The nodal musculature has the ability to generate action potentials without any external stimuli. i.e., it is auto excitable.  Action potential is a short-lasting event in which the electrical membrane potential of a cell rapidly rises and falls.  The SAN initiates conduction because it generates the maximum number of action potentials, i.e., 70-75 min-I, and is responsible for initiating the contractile activity of the heart. Therefore, it is called the pacemaker of the heart.  Myogenic heart is capable of generating a cardiac contraction independent of the nervous input. Myogenic heart © 2022, Aakash BYJU'S. All rights reserved. Electrocardiogram: ECG  It is used to measure the electrical activity of the heart.  An electrocardiograph is used to obtain an electrocardiogram (ECG).  An electrocardiograph is an instrument, and an electrocardiogram is the reading. Electrocardiograph Gel applied on the chest © 2022, Aakash BYJU'S. All rights reserved. Electrodes connected Electrocardiogram: ECG    It is a small upward wave that represents atrial depolarisation, which represents electrical excitation or atrial contraction. Depolarisation causes contraction. A normal ECG is composed of the following: o P wave o QRS wave o T wave  R T P Q P  S Normal healthy person’s ECG    © 2022, Aakash BYJU'S. All rights reserved. It begins with a downward deflection wave Q and continues as a large upright wave R. It ends into a downward wave S at the base of R. The contraction starts shortly after Q and marks the beginning of the systole. It is a small upward dome-shaped wave that represents ventricular repolarisation or relaxation. It represents the return of the ventricles from the excited to the normal state (repolarisation). Significance of ECG   Any deviation in the ECG indicates a possible abnormality or disease. Life = Ups and downs For example:  Enlargement of P wave indicates enlargement of the atria.  Myocardial infarction (MI) is shown by enlarged Q and R waves. Death = Flat line © 2022, Aakash BYJU'S. All rights reserved. Heart Diseases Coronary artery disease (CAD)  It affects the supply of blood to the heart muscle.  It is caused by the build up of plaque of the following: o Calcium o Fat o Cholesterol o Fibrous tissues  It makes the lumen of arteries narrower. © 2022, Aakash BYJU'S. All rights reserved. Plaque formation in the artery hindering the blood flow Heart Diseases Angina  It is also known as angina pectoris.  A symptom of acute chest pain appears when enough oxygen is not reaching the heart muscle.  It can occur in men and women in any age.  It is more common among the middleaged and elderly.  It occurs due to the conditions that affect the blood flow. © 2022, Aakash BYJU'S. All rights reserved. Enough oxygen does not reach the heart muscle due to narrowing of arteries Heart Diseases Heart attack Heart attack occurs when the heart muscle is damaged by inadequate blood supply. Heart having a portion of dead muscle tissue. Heart failure  Heart does not pump blood effectively enough to meet the needs of the body.  It is also known as congestive heart failure because congestion of lungs is a main symptom. © 2022, Aakash BYJU'S. All rights reserved. A clot blocking the blood flow. Heart Diseases Cardiac arrest  The heart stops beating.  The blood stops flowing to the vital organs. © 2022, Aakash BYJU'S. All rights reserved. Artificial pacemaker Pacemaker  Restores and maintains the normal heartbeat.  Used in the case of a blockage or a dysfunctional SA node. Regulation of Cardiac Activity Regulation of cardiac activity Nervous system Hormonal Medulla oblongata Adrenal medullary hormones Sympathetic Parasympathetic Increase the rate of the heartbeat, strength of ventricular contractions, hence the cardiac output Decrease the rate of the heartbeat, speed of conduction of action potential and hence the cardiac output © 2022, Aakash BYJU'S. All rights reserved. These hormones increase the cardiac output. Components of Blood Blood sample Glass slide Matrix Blood cells © 2022, Aakash BYJU'S. All rights reserved. It is a specialised fluid connective tissue that is responsible for the transport of oxygen and nutrients throughout the body. It carries away carbon dioxide and waste products from body cells. If you observe blood under a microscope, it appears like the given image. Blood is not just a thick and homogeneous liquid but comprises cells suspended in it. Components of Blood The fluid matrix of blood is known as plasma. Matrix Cells The cells of the blood are known as formed elements. Blood Blood Plasma © 2022, Aakash BYJU'S. All rights reserved. Formed elements Plasma Plasma is a straw-coloured, viscous fluid constituting nearly 55% of the blood volume. Proteins (6-8%) Plasma Plasma also contains small amounts of different kinds of molecules such as ions (Na+, Ca++, Mg++, HCO3–, Cl–), simple sugars, amino acids, lipids, urea, ammonia, carbon dioxide, oxygen, hormones, vitamins, etc. Blood Volume Dissovled components (