Human Cardiovascular System PDF

Heart and Blood vessels Lymph vascular system Dr. Udeshika Yapa Bandara BSc. (Hons) Human Biology (USJP), PhD (UOC) Learning outcomes At the end of the session, you should be able to: Explain the parts of circulatory system and their adaptations define blood flow, blood press...

Heart and Blood vessels Lymph vascular system Dr. Udeshika Yapa Bandara BSc. (Hons) Human Biology (USJP), PhD (UOC) Learning outcomes At the end of the session, you should be able to: Explain the parts of circulatory system and their adaptations define blood flow, blood pressure, resistance and explain the relationships between these factors list and explain the factors that influence blood pressure, and describe how blood pressure is regulated define hypertension and describe its manifestations and consequences explain how blood flow is regulated in the body in general and in its specific organs Introduction ‘cardio’ - heart ‘vascular’ - about blood vessels Consisting of the blood, heart and blood vessels  Circulatory system Two functional components Blood vascular system- active system circulating blood throughout body Heart-arterial system- microcirculation-venous system-heart Lymph vascular system - passive drainage system for returning excess extracellular fluid- lymph through lymph nodes to blood stream  Blood vascular system- Plan of circulation Heart Aorta - 2.5 cm diameter, 1.5mm thickness of wall thro’ Arteries (elastic, muscular) and Arterioles to millions of Capillaries ( total estimated length 60,000 miles) thro’ venules , veins to Heart From heart to finest vessel - one structural component is common- a single layer of endothelial cells which forms a smooth inner lining  Endothelium Squamous cells Polygonal in shape Joined by tight junctions Short microvilli Glycoprotein layer over luminal surface  Heart Heart – modified blood vessel Wall of heart - 3 main coats 1. Inner endocardium 2. Middle muscular layer - myocardium 3. External connective tissue – epicardium Endocardium Inner glistening layer continuous with and comparable to inner lining of blood vessels Squamous cells, polygonal shape Joined by tight junctions Short microvilli, glycoprotein layer over luminal surface Cells rest on a basal lamina deep to which a thick layer of connective tissue Subendocardial tissue (loose connective tissue) binds endocardium to heart muscle  Myocardium Made up of cardiac muscle cells that are arranged end to end and run in bundles In atria form prominent bundles Superficial layers continuous over both atria Inner layers independent for each atrium In ventricle fibre bundles run in different direction anchoring at atrioventricular junction Surrounding AV orifices strong fibrous rings - annuli fibrosi forms cardiac skeleton  Epicardium Mesothelium also lines parietal pericardium Secrete serous fluid Supported by thin layer of connective tissue Bound to myocardium by adipose connective tissue in which lie the branches of coronary blood vessels  Blood vessels -Structural organisation Smooth endothelial lining surrounded by fibres (collagen, elastic, reticulin) & smooth muscle cells and fibroblasts Arranged in 3 zones tunica intima tunica media tunica adventitia  Arrangement of structural elements Tunica intima single layer of endothelial cells and subendothelial connective tissue organised longitudinally Tunica media - muscle and elastic fibres between internal and external elastic laminae organised circumferentially Tunica adventitia connective tissue layer organised longitudinally – contain vasa vasorum  Functional adaptations Low friction lining - simple squamous Structural elements arranged to balance longitudinal and circumferential stress by pressure of blood Elastic recoil – modifies pulsatile nature of pressure and variations in blood flow Ability to control calibre by muscular action in response to varying functional demands Arterial system  Arteries Large elastic or conducting arteries - aorta, common iliac common carotids, wall is thin in relation to width of lumen made up mainly of elastic fibres ability to stretch and contract passively to maintain pressure in system Muscular or distributing artery largest number of arteries wall thick one quarter of diameter of lumen ability to alter the size of the lumen depending on blood needed made up mainly of smooth muscle fibres regulation of diameter under nervous control Arterioles small arteries less than (250-300um) with relatively narrow lumen and thick muscular wall offers considerable resistance to blood flow permitting high pressure to build up  Arteriole T. Intima- T.intima endothelial cells elongated in long axis impermeable IEL well developed occluding junctions T.media IEL-Scattered elastic lamina not complete Disappear in smaller arterioles T. Media Circularly arranged smooth muscle outermost layer spiral Myoendothelial junctions at points where elastic lamina is lacking T. Adventitia Poorly developed. Fine network of collagen , few elastic fibres Capillary circulation Small diameter capillaries containing only a single layer of endothelial cells Larger diameter capillaries with a discontinuous outer layer of muscle cells- metarterioles Small capillaries arise both from arterioles and metarterioles Sphincter mechanism at origin of each capillary Metarterioles also form direct communications between arteriole and venules  Capillaries 7-9um Endothelium Single layer of cells(2-3 in small capillary, 4-5 in large capillary) Flattened polygonal cells with irregular borders Seen on surface as a delicate mosaic Long axis of cell parallel to longitudinal axis of tube with nuclei bulging into lumen Thin glycoprotein coat on luminal surface Short microvilli Physiology of cardiovascular system  The cardiac conduction system Pacemaker regions S-A node and the A-V node S-A node - Electrical current rapidly spreads to other cells in the atria Atrial contraction Then spreads to the A-V node, before entering the ventricles Spreads along the cardiac conduction system of the ventricles  Regulation of heart rate S-A node Determine the heart rate Damage of S-A node A-V node determine the heart rate (But slower than the normal) Normal heart rate about 72 beats/min  The Electrocardiogram/ECG Records the electrical current generated by the heart Useful tool for diagnosing abnormalities (changes in the wave shape in the time intervals between events) related to heart function Normal ECG pattern for one cardiac cycle The cardiac cycle Cardiac cycle - Atrial and ventricular contractions and relaxations occur during one heartbeat Period of contraction – Systole Period of relaxation – Diastole Cardiac output Amount of blood pumped out of the heart by a ventricle, in one minute Cardiac Output (COP) = Heart Rate x Stroke Volume 5,040 mL/min = 72/min x 70 mL/beat Heart Rate = Number of times the heart beats per minute Stroke Volume = Volume of blood pumped with each beat Activity of Heart Rate Cardiac Provide more Exercise sympathetic oxygenated Force of output blood nervous contraction of system the heart (Stroke volume) Starling's Law of the Heart The degree of stretch of the ventricle walls, which is determined by the volume of blood in the ventricles, influences the force of contraction of the ventricles Blood pressure values in different parts of the CVS Systolic blood pressure - 120mmHg Maximum blood pressure in the arteries during ventricular systole Diastolic blood pressure - 90mmHg Lowest arterial blood pressure, when the ventricles are relaxed Pulse pressure - 30mmHg Difference between the systolic and diastolic pressures MAP - 100mmHg Average pressure of the blood in the arteries MAP = DP + Pulse Pressure 3  Two major factors influence the MAP: Total Peripheral resistance (TPR) and Cardiac Out Put (COP) Sympathetic activity Vasoconstriction TPR MAP Regulation of blood pressure Questions: 1. Describe the physiological process of regulation of blood pressure. 2. Describe the cardiac cycle describing the closing and opening of the valves. Respiratory system Dr. Udeshika Yapa Bandara BSc. (Hons) Human Biology (USJP), PhD (UOC) Learning Outcomes At the end of the session, you should be able to: describe the process of inspiration and expiration describe internal and external respiration describe pulmonary circulation briefly describe the process of diffusion of gases briefly explain the process of gas transport identify the neural control of respiration identify important respiratory adjustments in health  Functions: - Supplies O₂ and removes CO₂ - Filters inspired air - Produces sound - Contains receptors for smell - Rids the body of some excess water and heat - Helps to maintain blood pH Two regions: - Air conducting region - Gas exchanging region  Inspiration & Expiration Muscles involved in breathing - Intercostal muscles & diaphragm https://www.youtube.com/watch?v=NM3PK5qy9uA Gas exchange in the lungs Gas exchange in the tissues PO2 (Tissues) = 40 mmHg PO2 (Arterial blood) = 100 mmHg PCO2 (Arterial blood) = 40 mmHg PCO2 (Tissues) = 45 mmHg Pulmonary Circulation Blood gas transport O₂ transport - 97% enters RBCs & attach to Hb - 3% dissolve in the plasma - Alveoli O₂ moves Blood plasma PO₂ equalized on respiratory membrane - Hb Sucking up O₂ molecules from blood Until “saturated” with O₂ - Extra O₂ “Spill over” into plasma Diffusion between alveoli & blood Stop the diffusion Plasma PO2= Alveolar PO2 - Hb molecule can transport a total of 4 O2 molecules Saturated (Red colour) - Blood in capillaries around alveoli PCO2 & PO2 Hb affinity for O₂ - In tissues PCO2 & PO2 Hb affinity for O₂ O₂ break away from Hb - Temperature Hb affinity for O₂ Hb - Temperatures affinity for O₂ Release of O₂ from Hb - pH Hb affinity for O₂ - pH Hb affinity for O₂ Release of O₂ from Hb  Carbon dioxide transport - CO₂; Waste product of cellular respiration - Transport from tissues to lungs - 7% CO₂ Dissolve in the plasma - 23% Bind to Hb (globin part) - 70% Transport as HCO₃⁻ in the plasma - CO₂ diffuses into RBCs CO2+H2O H2CO3 HCO3⁻ + H+ - HCO3⁻ diffuse out of RBCs into plasma - H+ remains in RBCs - When blood reaches the lungs HCO3⁻+ H+ H2CO3 H2O+ CO2 (Diffuse out of blood into alveoli)  Respiratory volumes Tidal volume - 500 ml - Amount of air that moves into/out of lungs with each inspiration / each expiration Inspiratory Reserve Volume (IRV) - Air inspired with a maximal inspiratory effort in excess of the tidal volume Expiratory Reserve Volume (ERV) - Volume expelled by an active expiratory effort after passive expiration Residual Volume - Volume of air left in lungs after a maximal expiratory effort Respiratory dead space - Gas that does not exchange with blood in the pulmonary vessels  Forced vital capacity (FVC) - Largest amount of air that can be expired after a maximal inspiratory effort - Amount of air inspired per minute – 6L Tidal volume X No. of breaths/min = 500 mL/ breath x 12 breaths/min  Neural control of respiration - Regulates by respiratory centre located in the brain stem (Pons and Medulla) - Cortex of the brain – Regulate up to some extent Dorsal Respiratory Group (DRG) - Depolarize spontaneously Contraction of diaphragm & muscles related to inspiration - When quiet Relaxation of muscles Expiration Ventral Respiratory Group (VRG) - Quiet during normal breathing - Active when forced breathing occurs (Eg: During exercise) Pneumotaxic area/ Apneustic area – Pontine respiratory group - Direct contact with DRG Regulate the length of the inspiratory activity  Chemoreceptors  Stretch receptors - Receptors are located in the walls of the lungs - regulate the depth of breathing Overstretching of lung tissue Impulses to Pneumotaxic centre Duration of inspiration prevent overfilling of lungs  Lung surfactants - Secrete by special cells in the alveoli walls - Reduce the development of surface tension - Prevents the alveolar walls from sticking together  Lung compliance Referred as stretchability /distensibility of lungs Measure of change in lung volume (ΔVL) that occurs with a given change in the Transpulmonary pressure Transpulmonary pressure -Difference between the alveolar pressure and the intrapleural pressure in the pleural cavity Ptp = Palv – Pip Determine by 2 factors: - Distensibility of lung tissue - Alveolar surface tension  Lung Function Test Spirometry - pulmonary function test / lung function test - test measures the flow of air through your lungs and estimates the amount of air in your lungs. - It also tells a healthcare provider how strong your lungs are and how well you breathe. - a safe method Why is spirometry performed? Determine your lung capacity. Measure changes over time that occur as a result of chronic lung diseases. Identify early changes in your lung function and, in some cases, help guide treatment. Detect narrowing of your airways. Decide how likely it is that inhaled medications may help with your symptoms. Show whether exposure to certain substances has altered your lung function. Estimate your risk of respiratory complications before undergoing surgery.  Questions 1. a. What is meant by lung compliance? b. List two factors that affect lung compliance. 2. Explain the gas transportation in the human respiratory system with the effect of temperature and pH. Digestive system Dr. Udeshika Yapa Bandara BSc. (Hons) Human Biology (USJP), PhD (UOC) Learning Outcomes At the end of the session, you should be able to: List the parts of the digestive tract Describe the functions of oesophagus, stomach, liver, gall bladder, intestines describe mechanical digestion describe chemical digestion describe the digestive functions of the small intestine and its secretions outline how nutrients are absorbed in the small intestine Main Function of the GIT - Supply the body with nutrients and water Nutrients required by cells are - Large quantities of carbohydrates - Monosaccharides (Glucose & Fructose) - Fats (Glycerol & Fatty acids) - Proteins (Amino acids) - Small amounts of vitamins & minerals Digestion - Process of breaking down of food into small particles enough to be absorbed by -Mechanical digestion -Chemical digestion  Digestion Phases Include 1. Ingestion 2. Movement 3. Mechanical and chemical digestion 4. Absorption 5. Elimination Mechanical digestion in the mouth Teeth Break up food into smaller pieces - Which provides larger surface area to act digestive chemicals - Easy to swallow Saliva Food Mix with saliva (bolus) Easy to swallow Starch & glycogen Amylase Maltose Deglutition (Swallowing) 1. Oral Phase – Bolus moves from oral cavity into the oropharynx; voluntary process 2. Pharyngeal Phase - Bolus moves from the oropharynx into the oesophagus; involuntary process 3. Oesophageal phase - Bolus moves through the oesophagus and into the stomach; involuntary process  Functions of oesophagus Transfer of food from mouth to stomach Prevent regurgitation of gastric content by lower oesophageal sphincter (LOS) Prevent regurgitation of oesophageal content into respiratory passage by UOS Secretion of mucus by compound and simple mucous glands Gastro – oesophageal reflux Due to weakness of LOS leading to reflux of the acidic gastric content to the lower part of the oesophagus Risk factors: Obesity Pregnancy Smoking Connective tissue disorder (Scleroderma) Hiatal hernia Delayed emptying of stomach Functions of stomach Temporary storage – allowing time to act digestive enzymes like pepsin Chemical digestion – pepsin breaks proteins into polypeptides Mechanical breakdown Limited absorption (Alcohol, drugs) Non specific defence against microbes Preparation of iron for absorption Production and secretion of intrinsic factors needed for absorption of Vit. B12 Regulation of the passage of gastric content into duodenum Gastric mucosal barrier A compact epithelial cell lining A special mucous covering Protects the cells from contents of the stomach Luminal membranes of cells are impermeable to protons Cells are tightly adjoined Rapid turnover If damaged, peptic ulcer may result  Chemical digestion in the stomach Mucus Main components of gastric juice are; - Sticky - Mucus, Pepsin, HCL, Water - Alkaline secretion - Protects GIT from damage by the other gastric secretions Pepsin - An enzyme - Helps to digest proteins Large protein Short strands of AA HCl Pepsinogen Pepsin Control of gastric secretions See/Smell/Taste Food - Brain via parasympathetic nerve Gastric juice Gastrin (From gastric glands) (From stomach &SI) Gastrin production enhanced when - food is present in the stomach - pH of the stomach contents - parasympathetic nerves send signals  Food mixed with gastric juice - Chyme (partially digested CHO & proteins) Peristaltic movements of stomach force small amounts of chyme through the pyloric sphincter, into SI Chemical digestion completes in SI Chemical digestion in the SI Pancreatic juice - Polysaccharides Amylase Disaccharide (Maltose) - Fats Lipase Glycerol & Fatty acid - Long chains of amino acid Peptidases Short chains of AA - Sodium bicarbonate Neutralize acidity of chyme Bile - Consists with water, bile salts, cholesterol, bilirubin & other substances - Bile salts help to digest fats Intestinal enzymes - Peptidase - Completes the digestion of peptides to AA - Lipase - Completes the digestion of fats to glycerol & fatty acids - Sucrase, Maltase & Lactase - Digest disaccharide to monosaccharides (Glucose & Fructose) Pancreatic juice - Release pancreatic juice when arrival of chyme - Two components i. Digestive enzymes Amylase, Lipase & Peptidase ii. Alkaline secretion Contains sodium bicarbonate which neutralize the acidic chyme Absorption in the SI - CHO Glucose & fructose, absorbed via carrier proteins, active or passive - Proteins AA, enter brood via active transport mechanisms - Fats Glycerol & fatty acids, diffuse across the epithelial layers to the lacteals & transported through lymphatic system and enter the blood - Water, electrolytes & vitamins Large intestine - Very little digestion - Absorb water and electrolytes from the chyme - Formation and storage of faeces - Stretch receptors in sigmoid colon & rectum trigger the reflex Strong peristaltic movements Opening of the anal sphincters Faeces excrete from the body Vomiting reflex  Liver and gall bladder Functions of liver- Removing metabolic waste products Producing bile to aid in digestion Processing nutrients absorbed from the digestive track Storing glycogen, certain vitamins, minerals Maintaining normal blood sugar Synthesizing plasma proteins, albumin, clotting factors Producing immune factors and removing bacteria Removing senescent RBC from the circulation Excreting bilirubin Functions of gall bladder Regulate equalization of pressure in biliary system Effect on pH of bile Concentration of bile – becomes thicker, viscous and darker Storage of bile – (30-50 mL) Secretion of bile Functions of bile Most of the functions of bile due to presence of bile salts. Digestive function Absorptive function Excretory function Laxative action Antiseptic action (unconjugated bile acids) Maintenance of pH in GI tract Prevention of gallstone formation (cholelithiasis) Lubrication function Question 1. 24 years old Nimal had a lunch with rice, pork and green beans and green leaves. Outline the digestion of complete meal of Nimal.