Human Bio Exam Rev (Sem 1) PDF

INTRODUCTION - METHOD - Handwritten CELL STRUCTURE / TRANSPORT - Organelles - Structure of cell membrane as related to transport of materials - Comparing active / passive transport - Diffusion - concentration gradients / factors affecting exchange of materials (SA/vol ratio) -...

INTRODUCTION - METHOD - Handwritten CELL STRUCTURE / TRANSPORT - Organelles - Structure of cell membrane as related to transport of materials - Comparing active / passive transport - Diffusion - concentration gradients / factors affecting exchange of materials (SA/vol ratio) - Osmosis, carrier mediated transport (facilitated & active), vesicular transport (endocytosis, exocytosis, phago/pinocytosis) - CELL STRUCTURE - Cell theory states all organisms are made of cells (basic unit of life and arise from pre-existing cells) - The structure and function of the human body result from the activities of all it’s cells, which can vary in size and shape, but all human cells have a basic similar structure - Cell membrane Ribosomes Lysosomes Cytoskeleton Cytoplasm / Endoplasmic Mitochondria Inclusions cytosol reticulum Nucleus Golgi apparatus Cilia / flagella Centrioles CELL MEMBRANE - Separates cell contents from the environment outside the cell, protecting it - Surrounds the cell, holding everything together - Membrane is semi-permeable and controls substances entering / leaving CYTOPLASM / CYTOSOL - Cytoplasm = including organelles, is the jelly-like / watery material inside the cell and fills all the space between the nucleus and cell membrane (where many chemical reactions occur) - Cytosol = liquid part of cytoplasm. A mixture of dissolved substances NUCLEUS - Usually one per cell, is the control center containing most of the cell’s DNA; containing inherited information (genes) - That determine the proteins made in the cell, control the structure of the cell and the way it functions - Its surrounded by the nuclear membrane; with nuclear pores allowing molecules to enter and leave the nucleus - The nucleolus is the dot inside the nucleus, contains RNA and it where ribosomes are produced - mRNA = carries DNA message to ribosomes - tRNA = brings amino acids to ribosomes RIBOSOMES - The site of protein synthesis, where amino acids join together to make proteins - May be free or attached to endoplasmic reticulum ENDOPLASMIC RETICULUM (ER) - Network of membranes forming channels connected to the nuclear membrane - Used for storage, support, synthesis and transport within the cell and provide a surface on which chemical reactions occur - ROUGH = ribosomes attached - SMOOTH = no ribosomes attached GOLGI APPARATUS (aka golgi body) - Series of flattened membranes stacked on one another - Stores, modifies and repackages proteins for secretion from cell, coming from ribosomes passing through ER to golgi body. - Vesicles formed at edges of golgi body LYSOSOMES - From golgi body, contain digestive enzymes that break down large molecules and digest worn out organelles - Join with vesicles where enzymes break down whats in the vesicles for digestion or other other uses MITOCHONDRIA - Where cellular respiration occurs to release energy for cell use - Couple membrane structure with it’s own DNA, the inner membrane folded to produce a large surface area for cellular respiration to take place - The site of aerobic respiration (glucose + oxygen → CO2 + H2O + ATP) CILIA & FLAGELLA - Cilia = short, numerous projections resembling tiny hairs - Flagella = one or two longer single tails - Beat back and forth to move entire cell or parts of cell  CYTOSKELETON - Act as skeleton and muscle to the cell, providing shape and structure - Microfilaments help move materials around cytoplasm / move whole cell INCLUSIONS - Chemical substances not part of cell structure, but in the cytoplasm (haemoglobin or melanin) CENTRIOLES - Aids in cell division - CELL MEMBRANE - Separates internal / external environment and regulates the movement of materials going in / out - Regarded as a fluid mosaic model, where fluid refers to constant movement of molecules and mosaic being composed of many different types of molecules - - It composes of phospholipid molecules (lipid molecules + phosphate group), arranged in a bilayer - Each molecules has a hydrophilic phosphate head and a hydrophobic fatty acid tail - - Has a variety of protein molecules; - Receptor proteins - Channel proteins - Carrier proteins - Cell-identity markers - Membranes are permeable to: - Lipid soluble substances BUT NOT - Tiny water molecules - water, urea - Most water soluble substances - Small uncharged molecules - Ions - CO2, O2 - Polar molecules - Large water soluble substances - Amino acids  - More functions - Physical barrier sensitive to changes - Binding site for enzymes - Regulation of passage - Contains cytoplasm - Support cells - CELL TRANSPORT - The transport in and out of cells in controlled, occurring by either DIFFUSION (passive process), FACILITATED TRANSPORT (active or passive transport) or VESICULAR TRANSPORT (active process) - ACTIVE vs. PASSIVE ACTIVE BOTH PASSIVE Against diffusion Movement of molecules With diffusion Low to high Pass through cell High to low concentration membrane concentration Requires energy Has regulatory functions No energy required Always has protein Sometimes involve channel protein channel - DIFFUSION FACILITATED ACTIVE TRANSPORT DIFFUSION Passive process Requires a special Process in which resulting from random protein in the cell materials are moved in movement of ions / membrane, may be membrane bound sacs - molecules passive or active an active process *Osmosis; type of (depending on the diffusion where water nature of the passes across a mechanism) membrane - DIFFUSION  - The spreading out of particles so that they are evenly distributed - Transport of substances from region of high to low concentration through a concentration gradient - Concentration gradient - the difference in concentration bringing about diffusion - *A greater difference in concentration = faster rate of diffusion - Alcohol, steroids, fat-soluble substance, O2 and CO2 can diffuse through lipid portions of membrane but - Not WATER-SOLUBLE molecules, which need a protein channel to diffuse through - OSMOSIS - Movement of water molecules across a semi-permeable membrane from a region of high water concentration to a region of low water concentration - Or from an area of low concentration of solute to a high concentration of solute. - Differences in concentration on either side of a membrane is called osmotic pressure - FACILITATED DIFFUSION - Passive; moving substances from high to low concentration - Transporting required molecules (glucose / amino acids) too large to fit through the membrane and use a carrier protein - The molecules bind to the binding site on the specific carrier-protein and change shape to move the molecules across the membrane, releasing it on the other side - CARRIER-MEDIATED TRANSPORT CHARACTERISTICS - Specific carrier proteins - Can become saturated (has maximum rate of transport) - Regulated by substances like hormones - ACTIVE TRANSPORT - Can be either carrier-mediated or vesicular - Require energy moving molecules AGAINST concentration gradient CARRIER MEDIATED active VESICULAR requires energy to form transport requires energy to change the vesicles to transport substances shape and release molecules within the membranous sacs - ENDOCYTOSIS - Taking in solids or liquids, the membrane encloses and pinches off to leave vesicle suspended - PINOCYTOSIS - PHAGOCYTOSIS - EXOCYTOSIS - Contents of vesicles passed out the cell TYPE OF ACTIVE / EXPLANATION SUBSTANCE PICTURE TRANSPORT PASSIVE EXAMPLE REFERENCE Simple Diffusion Substances small Water, O2, CO2, enough / lipid soluble alcohol, fatty acids, can easily diffuse steroids, lipid through the cell soluble drugs membrane, moving Ions: Na, K, Ca with concentration gradient. Osmosis Special type of Water Passive diffusion of solvent (H2O) through a semipermeable membrane in order to balance the concentrations of other substances Facilitated Transport of Glucose Diffusion substance into the cell Amino Acids with the assistance of a protein Active Transport Transport of Large molecules substance into or out Certain ions of the cell, with the Glucose use of energy, via a Amino acids protein. This movement is against concentration gradient Pinocytosis Cell drinking, intake of Liquids fluid by vesicular transport. Membrane folds around the droplet of fluid. Active Phagocytosis Cell eating, intake of Cholesterol solids by vesicular Iron transport. Membrane Micro-organisms folds around and engulfs particles. Exocytosis Removal of contents Secretions such as from inside the cell mucus, enzymes through vesicular and digestive juices transport. Vesicle fuses with cell membrane, emptying contents into ECF - FACTORS AFFECTING EXCHANGE OF MATERIALS - Size of particles - Larger molecules diffuse through slower - The smaller the molecules, faster rate of diffusion - Concentration gradient - Greater difference in concentration, greater concentration gradient - Greater concentration gradient = faster rate of diffusion - Temperature - Increase in temperature = increase in kinetic energy - K.E. = energy something possesses due to motion - Temperature increases, so does motion and therefore rate of diffusion - Surface area : volume ratio - The larger the area over which diffusion can occur = greater rate of diffusion - “Cells are very small, which gives them a large surface area compared to volume. Increasing surface area to volume ratio improves efficiency in exchange of materials. As the surface area and volumes of an organism increase, The SA : V ratio decreases. This is because volume increases much more rapidly than surface area as size increases” - SOLUTIONS - Solution = homogeneous mixture of one or more solutes dissolved in a solvent - Solvent = substance in which a solute dissolves to produce a homogenous mixture - Solute = substance that dissolves in a solvent - ISOTONIC SOLUTIONS - Concentration of solutes same inside & outside cell - HYPOTONIC SOLUTION - Concentration higher inside cell (less solute/more water in solution) - Water transported into cell; cell will swell & burst - HYPERTONIC SOLUTION - Concentration higher outside cell (more solute/less water in solution) - Water comes out of cell; cell shrivels up - TISSUE TYPES - TISSUE = group of cells similar in structure, work together to carry out particular task TYPE OF TISSUE FUNCTION STRUCTURE Epithelial Form covering or lining of all - Closely packed cells internal & external body - One or more layers surfaces (whole surface of body) Connective Provides support / hold body - Cells + matrix - Bone, cartilage, together (so everything doesn’t - Cells not tightly packed tendon, ligament, float around) together, separated by fat, blood non cellular tissue called matrix Muscular - able to respond to stimulus - Long & thin, often called - Bones, walls of (contract) muscle fibres certain organs, - SKELETAL (voluntary) - Striated / striped most of heart - — muscle attached to bones - SMOOTH (involuntary) - Smooth, not striped - — walls of stomach / intestines, blood vessels, iris - CARDIAC (involuntary) - Striated / intercalated disks, branched, nucleus - — most of heart Nervous Sense stimuli & transmit - Neurons: signals to and from parts of an - Cell body = w/ nucleus, organism cytoplasm & organelles - AXON -single long length, carry signals away - DENDRITES - smaller protrusions, carry signal towards cell - ORGANS - Are body structures made up of 2 or more tissue types that work together to carry out a specific function, usually has a distinct shape - SYSTEMS - System of organs working together to carry out a specific task - 11 main systems in human body METABOLISM - ORGANIC COMPOUNDS = large molecules containing carbon, most substances involved in metabolism are organic - INORGANIC COMPOUNDS = do not contain carbon or are small ORGANIC INORGANIC Have carbon chain Not based on a carbon chain - Carbs - Water - Lipids - Minerals - Proteins - vitamins - Nucleic acids NUTRIENT FOOD SOURCE MONOMERS FUNCTION Carbohydrates Pasta, rice, potatoes Monosaccharides Main source of energy (Glucose & fructose) Combine other *CHO* Disaccharides substances (sucrose & lactose) Stored in liver as Polysaccharides glycogen (glycogen, cellulose, starch) Lipids Butter, oil, cholesterol Fatty acids / glycerol Insulation, long term energy, protection of *CHO* organs Structural function — cell membrane, myelin sheath Metabolic function — cholesterol, steroids Protein Meats, eggs, tofu Amino acids Oxygen transport, protection, energy *CHON* source (in emergencies) Structural function — actin / myosin in muscles Metabolic functions — enzymes Nucleic acid DNA & RNA nucleotide DNA - genetic material RNA - carry info from *NOT NUTRIENT, DNA to where cells BIOMOLECULE* make proteins *CHONP*  - INORGANIC COMPOUNDS - Water - Minerals - Cofactor for enzyme - May be a part of a substance involved in metabolism - Vitamins - Coenzyme - METABOLISM - all chemical reactions in cells - CATABOLISM - large molecules broken down to smaller ones (digestion) releases energy - ANABOLISM - smaller molecules built up into larger ones (protein synthesis) requires energy - ENZYMES - proteins produced by living organisms, acts as biological catalyst to reduce energy for a specific chemical reaction, speeds up reactions - Catalyst = increases rate of reaction without itself being changed - Each enzyme = specific; involved in a specific reaction which assists in building or breaking of molecules / substances - Specific shape gives specific ACTIVE SITE - Active site has to compliment shape of substrate ACTIVATION ENERGY - energy needed to start a chemical reaction - *enzymes function by lowering A.E. - - LOCK-AND-KEY MODEL I. Enzyme + substrate in same area II. Two collide, enzyme grabs onto substrate with active site. Should fit exactly III. Forms enzyme-substrate complex - catalysis. Substrate changes (broken down / combined) IV. Enzymes detach, enzymes return to normal ready for next. Substrate becomes product - - INDUCED FIT MODEL - “When enzyme + substrate join, the weak bonds formed cause shape of enzyme to change to make complementary shape” - FACTORS AFFECTING ENZYME ACTIVITY 1. Enzyme concentration - Higher concentration = faster RoR - Because more enzyme molecules to influence reactants - *inc substrate concentration can also inc RoR but will need to continually removed lest they build up and becomes harder for substrate molecules to make contact with enzymes 2. Temperature - Rate of most chemical reactions inc with heat, but only in a certain range - Too high can deactivate enzymes (denatured) permanently changing the active site, becoming useless. 3. pH - Enzymes sensitive to pH - All have optimum pH where work best - Vary with different enzymes 4. Co-factor / coenzyme - Some enzymes require presence of certain ions / non-protein molecules before willing to catalyse - Cofactors change the shape of an active site so the enzyme can combine with substrate. Without cofactor, enzyme intact, nonfunctional - NON-PROTEIN COFACTORS = COENZYMES (many are vitamins) - 5. Enzyme inhibitors - Slow / stop enzyme activity 1. Used to control reactions (cell) 2. Synthesised by humans (penicillin) CELLULAR RESPIRATION - Process which organic molecules taken in as food are broken down (catabolic) in cells; release energy for cell activities, occurring in different locations in cytosol & mitochondria - Can release energy from glucose, amino acids, fatty acids & glycerol, but prefers glucose - Glucose + oxygen → carbon dioxide + water + energy (ATP & heat) - 60% energy released as heat - Cells can’t use, but keeps body temp constant - Remaining energy = forms ATP - Adenosine + 3 phosphate groups - *be used to transfer energy between cellular respiration & processes requiring energy - AEROBIC RESPIRATION - Complete breakdown of glucose into carbon dioxide & water 1. Glycolysis - cytoplasm 2. Krebs (citric cycle) - mitochondria 3. Electron transport - mitochondria - The mitochondria has a double membrane, with the inner membrane having enzymes attached for aerobic respiration - The folding therefore produces a large surface area, letting aerobic respiration take place - Increase of surface area = increased rate of reaction - GLYCOLYSIS - Glucose → 2 pyruvate + 2 ATP - *same for aerobic / anaerobic - CITRIC ACID / KREBS CYCLE - Presence of O2 2 pyruvate enter mitochondria = become acetyl CoA (enters citric acid cycle - in inner membrane) - Produces 2 ATP + CO2 + (NADH / FADH2) - ELECTRON TRANSPORT SYSTEM (CHAIN - Enzymes on inner membrane - Electrons from NADH / FADH2 released, passed along enzymes, giving up energy using enzyme ATPase (fueling chemiosmosis) driving 32/34 ATP synthesis - Electrons unit with O2 at end of chain making 6H2O - Glycolysis = 2 ATP - Citric acid = 2 ATP - Electron transport = 32/34 - 6CO2, 6H2O, heat (extra)  - ANAEROBIC RESPIRATION - Respiration without oxygen - First stage still glycolysis - No oxygen required so produces 2 pyruvate + 2 ATP - When no oxygen available pyruvate is converted to lactic acid by fermentation = aka anaerobic respiration (doesn’t produce any more ATP) - *all occurs in cytoplasm - Is important in vigorous physical activity when muscle cells aren’t met with enough oxygen to meet energy demands of contracting muscles - But, accumulation of lactic acid in muscles can then lead to muscle pain / fatigue - NEXT, - Lactic acid formed from anaerobic respiration is then taken by blood to liver, to recombine with oxygen to form glucose - Requires oxygen so physiologists say ‘when cells use anaerobic respiration our bodies form oxygen debt’ - ***we breathe heavily and keep moving after exercise so we can repay oxygen debt by converting lactic acid → glucose - Movement also reduces effect of DOMS (delayed onset muscle soreness) by moving lactic acid around the body - **oxygen obtained here called recovery oxygen - WHY DO OUR CELLS NEED ENERGY? - Chemical energy in glucose (from food) → chemical energy + heat energy —> - Build complex molecules - Cell division / growth - Movement of cell organelles / whole cell - Active transport - Transmission of nerve impulses - All also release heat energy CIRCULATORY SYSTEM - The circulatory system is the link between cells inside the body and the environment outside the body, comprising of the heart and heart vessels (veins, arteries and blood) FUNCTION OF BLOOD - Transport O2 and nutrients to cells, CO2 and waste away from cells - + transport hormones - Maintain pH of bodily fluids, water content and ion concentration - + maintain body temperature by distributing heat - Protect against disease-causing microorganisms It contains: - 55% plasma - 91% H2O - 8% dissolved substances: nutrients, ions, gasses, hormones and waste - Takes nutrients and hormones to cells and removes waste - 45% formed elements; erythrocytes, leukocytes and thrombocytes BLOOD PLASMA - Transports nutrients to body and gets rid of waste - Nutrients - Inorganic: - Transported as ions, e.g. (Na+), (Ca2+), (K+), (Cl-) - Organic: - Glucose, vitamins, amino acids, fatty acids, glycerol - Metabolic wastes - Urea, creatinine, uric acid FORMED ELEMENTS (any cell-like structure in the blood) ERYTHROCYTES - Transport oxygenated blood from the lungs to the body - Biconcave + no nucleus - Increased surface area for O2 exchange & thick edges give large volume for more haemoglobin - (can combine with O2 = oxyhaemoglobin) - O2 + haemoglobin = makes oxygenated blood red - Deoxygenated blood is dark red / purple - RBC has a lifespan of 120 days; and produced in bone marrow / destroyed in liver and spleen  LEUCOCYTES - Larger but fewer than RBC, also made in bone marrow - Involved in immunity; removes dead / injured cells and invading microogranisms - Lives for a few minutes during infection and up to years otherwise - Two types - GRANULOCYTES: granular cytoplasm & lobed nucleus - MONOCYTE / LYMPHOCYTES: agranular cytoplasm & spherical nucleus THROMBOCYTES - Small cell fragments; no nucleus (⅓ of RBC) - Formed in bone marrow, lives for about 7 days - Important in normal blood clotting TRANSPORT OF O2 & CO2 - 3% as blood plasma - 97% as oxyhaemoglobin - Oxyhaemoglobin can easily break down to release O2 + In the capillaries in the lungs oxygen will combine with haemoglobin - In situations of HIGH OXYGEN concentration - The opposite happens in situations of LOW OXYGEN concentration, oxyhaemoglobin breaks down and oxygen diffuses into tissue + Oxygenated blood = bright red - Deoxygenated blood = dark red / purple - 8% dissolved in plasma - 22% carbaminohemoglobin - 70% bicarbonate ions - CO2 convert to carbonic acid - broken down to H+ & HCO3- + CO2 dissolved in the plasma diffuses out of the capillaries into the alveoli. - Carbaminohemoglobin breaks down; CO2 released diffuses into alveoli. - H+ & HCO3- recombines into carbonic acid, then breaks down into CO2 & H2O BLOOD CLOTTING 1. VASOCONSTRICTION - Muscle in capillaries constrict to reduce blood loss 2. PLATELET PLUG FORMATION - Platelets stick to the blood vessel wall (site) - Other platelets are attracted, joining together, forming a platelet plug ENOUGH FOR MOST INJURIES 3. COAGULATION - Clotting factors (chemical substances allowing blood to clot) - Sends signals and causes reactions to produce fibrin - Factors activate till threads of insoluble protein; fibrin is formed - Fibrins form a mesh; trapping blood cells, platelets and plasma = clot 4. CLOT RETRACTION - Fibrin contracts, pulling edges of damaged blood vessels together - Fluid known as serum is squeezed out - Clot dries, forms a scab over the wound - Preventing entry of infecting microorganisms and pathogens STRUCTURE OF THE HEART - Heart; pump that pushes blood around the body - Located in thoracic cavity between 2 lungs slightly on the left - Made up of cardiac muscle and is approximately the size of a clenched fist - Covered by a membrane known as a pericardium that - Secretes fluid reducing friction - Holds heart in place but allows for movement while breathing - Prevents heart from overstretching ATRIOVENTRICULAR VALVES - Blood flow from atrium to ventricles - Flaps of thin tissue, edges held by tendons - *T - 3 flaps - *M - 2 flap SEMILUNAR VALVE - Between ventricle and arteries - 3 cups - Flattens against the artery wall; blood flows in and the cups fill out sealing off the opening. STRUCTURE & FUNCTION OF THE BLOOD VESSELS ARTERIES - Blood away from heat - Blood pressure increases as ventricles contract, decrease as ventricles relax Thick, muscular, elastic walls made of smooth muscle ○ Can change diameter, no valve - ARTERIOLES - Small arteries (carry blood to capillaries) VEINS - Blood to heart Thin walls + valves which direct blood to heart and prevent backflow - VENULES - Tiny veins (carry blood away from capillaries) CAPILLARIES - Microscopic blood vessels + form a network - Carry blood to nearly every cell in body - 1 cell thick for exchange of nutrients and O2 between blood and body cells  - BLOOD FLOW IN ARTERIES & VEINS - Blood in the right atrium and ventricle are deoxygenated, from the body, sent to the heart to go to the lungs - Vena cava → RA → t-vavle → RV → p-valve → pulmonary artery - Blood in left atrium and left ventricle are the opposite; oxygenated goes from the lungs to the heart to the body - Pulmonary vein → LA → m-valve → LV → a-valve → aorta ARTERIES VEINS CAPILLARIES Function Carry blood away Carry blood towards Exchange of materials from the heart the heart between blood & body cells Pressure High Low Low Lumen Diameter Small (narrow) Large (wide) Extremely narrow (one cell wide) Wall Thickness Thick Thin Extremely thin (single cell thick) Wall Layers 3 3 1 Muscle & Elastic Large amounts Small amounts None Fibres Valves no yes no VASOCONSTRICTION & VASODILATION - Vasoconstriction - Decrease in diameter and blood flow due to muscle of artery wall contracting - Vasodilation - Muscle relaxes, increase in diameter and allow more blood flow - FACTORS AFFECTING blood vessel diameter - Adrenaline - vasoconstriction in arterioles, but skeletal muscles & heart - vasodilation - Increased oxygen supply + removal of waste = vasodilation THE CARDIAC OUTPUT - Sequence of events in one heartbeat - SYSTOLE: pumping phase - when the heart muscle contracts - DIASTOLE: filling phase - heart muscle relaxes - Atrial systole: contraction of atria (moves blood into ventricles) - Ventricular systole: contraction of ventricle (move blood out of heart) - Volume of blood forced Amount of blood leaving Number of times heart from a ventricle with each the ventricle each minute beats per minute contraction - BLOOD PRESSURE - Pressure in the arteries as blood is pumped around the body by the heart - Affected by sleeping, breathing, emotional state & exercise High blood pressure = heart attack, stroke, heart failure / kidney disease ○ Hypertension = elevated blood pressure levels ○ Hypotension = lower-than-normal blood pressure levels - Sphygmomanometer - inflatable pressure cuff - 2 number measured, e.g. 120/80 - 120 = systolic blood pressure - 80 = diastolic blood pressure ABO BLOOD GROUPS - ANTIBODIES (immunoglobulins) - Y-shaped proteins made by body - Help to fight against foreign substances called antigens - ANTIGENS (any substance that stimulates antibody production) - E.g. bacteria, virus, fungi Antibodies are produced in response to antigens, and can combine with antigen that initiated response - ANTIGENS can be found on the surface of RBC - 4 main groupings: A, B, O, AB - Each group has different antigens (except O) Blood Group Antigens on RBC Antibodies in plasma A Antigen A Antibody -B B Antigen B Antibody -A AB Antigen A & B No antibody O No antigens Antibody A & B - AGGLUTINATION - Mixing of incompatible blood types / clumping of RBC - RHESUS FACTORS - ABO - sugars, Rh = proteins - Rh + = have antigen, no antibody - Rh - = no antigen, has antibody for it TRANSFUSION TYPES Part of blood used Medical use Whole blood Plasma & cells Severe blood loss Red cell concentrates Cells only (may contain red Most commonly used (e.g. cells only, x plasma) anemia, heart disease) Plasma Liquid part of blood Severe bleeding, extra clotting factors, liver disease LYMPHATIC SYSTEM - Function - Collect escaped fluid from blood capillaries and return it to the circulatory system - Important part of body’s internal defense against disease-causing organisms - Also: - Drains excess fluid from tissue - Remove debris from cells of body - Transport fats from digestive system Lymph - interstitial fluid that flows into the lymphatic system - Formed from blood by the passage of substances through the wall of the blood capillaries into the inner cellular tissue spaces by the process of diffusion and filtration from the blood. + - Consists of 2 parts; fluid matrix (plasma) & WBC (leucocytes) + - About 120 ml of lymph flows through the lymphatic system per hour into blood. Lymph Vessels (lymph capillaries joined together) - Originate as blind-ended tubes in the spaces between cells of most tissues. - Usually slightly larger and more permeable than blood capillaries. - Muscular walls & valves. - Disease causing organisms can easily pass through the walls of lymph capillaries. - Network of lymph vessels join up to form 2 lymphatic ducts that empty that lymph into large veins in the upper chest Lymph nodes - Aka lymph glands, they occur along lymphatic vessels - Most common in the neck, armpits, groin & alimentary canal. - Bean-shaped, length from 1mm - 25mm - Surrounded by a capsule of connective tissue that extends into the node, forming a network. - Lymph entering lymph nodes contains: - Cell debris - Foreign particles - Micro-organisms (penetrated the body’s external defenses) - Larger particles (like bacteria) are trapped in the network of fibres as lymph flows through spaces in the nodes - Phagocytic cells (macrophages) destroy these particles  DEFENCE - During infection, formation of lymphocytes (produce antibodies) increase - Lymph nodes become swollen and sore 1. Membrane envelopes 2. Form vacuole with engulfed object 3. Fuses with lysosome 4. Digestion of material 5. Products released FLUID BALANCE - Blood enters capillaries at high pressure - Some fluid forced out of thin walls into tissues - Some return at venous end of capillaries - Lymphatic system collects excess fluid escaped from capillaries and returns to circulatory system ABSORPTION OF FATS - Absorption of fats and fat-soluble vitamins from the digestive & transport - The mucosa that lines the small intestine is covered with villi - Blood capillaries - Lymph capillaries (lacteals) - Blood capillaries absorb most nutrients but fats and fat-soluble vitamins are absorbed by the lacteals LYMPHATIC SYSTEM: TRANSPORT - Lymph moves through vessels due to: - Smooth muscle - Able to contract; push lymph along vessel - Skeletal muscle - Surrounding vessels contract allowing additional force - Larger vessels - Have valves that close when pressure drops  LYMPHATIC ORGANS - Tonsils and adenoids - Lymphocytes and macrophages protect against pathogens entering through nose & mouth - Spleen - Lymphocytes in the spleen react to pathogens in the blood and attempt to destroy them - Removes dead RBC and filter blood - Thymus - Maturation of special lymphocytes called T-cells - Produces hormone thymosin, which stimulates the maturation of lymphocytes in other lymphatic organs Circulatory system Lymphatic system Main function Main function is to carry Fluid balance and immune oxygen and nutrients and function removing wastes Type of fluid Carries blood Carries lymph What structures do fluids Moves through the heart, Lymph flows through lymphatic pass through for arteries, capillaries, veins and vessels transportation? lungs contains? Plasma, erythrocytes, Lymphocytes, which creates the leukocytes and platelets immune response Function in immune Leukocytes in blood pose a Lymphocytes of the lymphatic response defense against invading system help in building immunity foreign bodies and toxins Type of blood vessel Arteries, capillaries, veins Lymphatic vessels, lymph capillaries  RESPIRATORY SYSTEM - Structure that allows the efficient flow of air into & out of the lungs so that gas exchange can occur between the air & the blood Ventilation Respiration - Breathing - Is the transport of oxygen from the air - The process of moving air into & out to the tissues and the transport of of lungs carbon dioxide in the opposite direction. *not cellular respiration UPPER RESPIRATORY TRACT - Air enters the body through; mouth and nose - lined by mucous membranes - As air passes over membranes, it’s warmed and humidified - Traps debris, preventing it from reaching the lungs PHARYNX & LARYNX - The PHARYNX, or throat, air travels through before being diverted into the trachea by the epiglottis - The LARYNX is a cartilage structure joining the pharynx and the trachea. The larynx contains the vocal cords, which are mucous membranes that can vibrate as air passes over them. EPIGLOTTIS - During inhalation the EPIGLOTTIS covers the oesophagus, guiding the air into the trachea; when swallowing, the epiglottis covers the larynx, preventing food from entering it. - The epiglottis is a flap of elastic cartilage that makes sure to cover either the oesophagus or larynx when inhaling or swallowing respectively. LOWER RESPIRATORY TRACT - Functions - Trachea: transports air to and from lungs - Bronchi: branch into lungs - Lungs: transport air to alveoli for gas exchange TRACHEA - Windpipe that passes air from upper tract to lungs and back out, protected & supported by cartilage preventing collapse - The epithelial lining of the trachea produces mucus: trap dust & debris & prevent it from entering the lungs - Cilia are able to move in a wave-like motion to take the mucus & debris up to the pharynx so that it can be swallowed & digested / coughed up. BRONCHI & BRONCHIOLES - BRONCHI - At the end of the trachea, the structure splits into 2 primary bronchi, one for each lung - Split into secondary and then tertiary bronchi. - The bronchi are also made up of C-shaped cartilage rings - BRONCHIOLES - Tertiary bronchi become bronchioles; are made of smooth muscle and elastin. This allows the bronchioles to control the flow of air in the lungs, expanding when the body needs more oxygen LUNGS - Each lung is divided into lobes; left lung = 2, right lung = 3 lobes - A membrane, called pleura, covers the surface of the lungs (the visceral pluera) & also lines the inside of the chest (the parietal pleura). Between these 2 layers of membrane is a thin layer of pleura fluid. ALVEOLI (ALVEOLUS) - Each alveolus is surrounded by a network of blood capillaries. - The alveoli are the functional units of the lungs - This makes it possible for the alveoli to be the surface for gaseous exchange, allowing a net flow of oxygen to pass from the airways into the blood & CO2 to pass from the blood into the airways.  GAS EXCHANGE 1. The artery to the lungs brings deoxygenated blood to the capillaries 2. CO2 diffuses from the higher concentration in blood to lower concentration in air in alveolus ❖ The wall of alveolus and capillary is 1 cell thick; the inside of the alveolus is lined with a film of moisture. These make it easy for gas to diffuse to and from the body. 3. Oxygen diffuses from the higher concentration in air in the alveolus to lower concentration in blood 4. Oxygenated blood leaves the capillaries of alveoli and taken to the heart in the veins from the lungs PROCESS OF GAS EXCHANGE - Deoxygenated blood is transported to the lungs by the pulmonary artery. - CO2 diffuses from the BLOOD (high concentration) in the ALVEOLI (low concentration) and is expired. - O2 diffuses from the ALVEOLI (high concentration) into the CAPILLARIES (low concentration) and is transported around the body.  Lungs are well-suited to their function; Why? - Alveoli = huge internal surface area so that large amounts of gasses can be exchanged in a relatively short time - Lungs are positioned deep inside the body - Walls of the alveolus are very thin, so that gas molecules do not have to travel far when moving into or out of blood - Alveolus are well supplied with blood vessels - Lung volume can be changed by movement of respiratory muscles. ALVEOLI & GAS EXCHANGE - Each alveolus has a wall only one cell thick and surrounded by a network of blood capillaries, allowing efficient DIFFUSION OF GAS PRESSURE GRADIENTS - For diffusion of gasses into & out of the blood, there must be a CONCENTRATION GRADIENT - a difference in gas concentration between the air in the alveoli and the blood in the capillaries - The ways in which a concentration gradient for gas exchange occurs by: 1. Constant flow of blood in capillaries 2. Movement of air into and out of the alveoli as we breathe in and out.  MECHANICS OF BREATHING INSPIRATION EXPIRATION Intercostal muscles contract, extending rib Rib cage moves down and inwards cage upwards and outwards Diaphragm contracts, extending chest cavity Diaphragm relaxes, pushing up into chest downwards cavity Lung volume increases Lung volume decreases Air flows from higher pressure to lower Air flows from higher pressure in lungs to pressure in lungs lower pressure outside Pressure during inspiration - An increase in volume of lungs, decreases pressure in lungs - Pressure in lungs now less than pressure outside - *air is drawn into lungs to make pressure inside and outside equal Pressure during expiration - Decrease in volume of lungs increases pressure within lungs - Pressure in lungs now higher than pressure outside lungs - *air therefore drawn out of lungs to make pressures equal *lung pressure high → air flows in to equal pressure → muscle/diaphragm contracts (inc vol) → lung pressure low *lung pressure low → air flows out to equal pressure → rib cage down, diaphragm relax → lung pressure high *system repeats  RESPIRATORY SYSTEM: diseases - CHRONIC OBSTRUCTIVE PULMONARY DISEASE (COPD) - Related diseases that generally deal with chronic bronchial outflow obstruction with overlapping features - - ASTHMA - Chronic inflammatory disease of small bronchi and bronchioles; characterized by bronchospasm and air trapping, in which airflow out is impaired - Triggered by inhaled irritants and classified by irritant - Allergic - Occupational - Exercise-induced - Infectious - Others - Drug reactions - Emotional stress - Severe air pollution - EMPHYSEMA - Destruction of alveolar walls, alveoli merge to form large air spaces. - Loss of surface area affects diffusion - 90% of cases are smokers - Cigarette smoke irritates lung and causes inflammation, and inflammatory cells release digestive enzymes - These enzymes are normally inhibited by alpha-I antitrypsin - AAT is inhibited by smoke and so the enzymes will digest lung tissue.  DIGESTION - The alimentary canal - Continuous tube running from mouth to anus - The digestive system - Consists of the alimentary canal together with pancreas, gallbladder and liver. - FUNCTION OF THE DIGESTIVE SYSTEM - Ingest food and water - Mechanical / chemical digestion of food - Movement of food along alimentary canal - Absorption of digested food and water into blood & lymph - Elimination of material not absorbed - MECHANICAL DIGESTION - Physical breakdown of food into smaller pieces - Teeth = cutting, tearing and grinding of food - Stomach = churning of the stomach - Bile = emulsification of fats to droplets - CHEMICAL DIGESTION - Chemical breakdown of nutrients with the aid of enzymes, chemical reactions take place. - Carbs → monosaccharides - Proteins → peptides + amino acids - Lipids → fatty acids + glycerol - Nucleic acid → nucleotides THE STRUCTURE OF DIGESTIVE SYSTEM - Consists of hollow organs running from mouth to anus. - Mouth, pharynx, esophagus, stomach, SI, LI - Epithelial cells line tract. - TYPES OF DIGESTIVE TISSUE - Mouth, esophagus, anus: - Stratified squamous epithelial tissue (layered, flat, lining tissue) - Protection from friction / movement of food & other digestive products. - Stomach, SI, LI and colon - Made of columnar epithelial cells that secrete mucous, blood vessel (elongated lining cell) - Connective tissue (elasticity), and blood vessels - Smooth muscle and blood vessels  - The accessory organs are: - Teeth Tongue Salivary glands Liver Pancreas Gall bladder DIGESTIVE ENZYMES AMYLASE - breaks down starch - PANCREATIC AMYLASE - Breaks down starch into disaccharides, e.g. maltose - SALIVARY AMYLASE - Chemical digestion of starch - LYSOZYME - Within saliva - Immune defense mechanism (antibacterial) - MALTASE - Breaks down maltose → glucose - Produced in mucous membrane of small intestine - LACTASE - Digests & breaks down lactose → glucose / galactose - Produced in small intestine - SUCRASE - Breaks down sucrose → fructose & glucose - Produced in small intestine PROTEASE - breaks down proteins → peptides / amino acids - PEPSIN - Breaks bonds between amino acids → smaller polypeptides - Gastric juice of stomach (gastric chief cells) - TRYPSIN - Breaks proteins down further in small intestine - Produced by pancreas as trypsinogen - PEPTIDASE - Speeds up breakdown of proteins - Produced in stomach, small intestine, pancreas LIPASE - PANCREATIC LIPASE - Breaks down fats → fatty acids & glycerol - GASTRIC LIPASE - Breaks down fats → fatty acid & diglycerides - LINGUAL LIPASE - Produced from serous gland in tongue, begins fat digestion in mouth - NUCLEASE - Deoxyribonuclease = breaks down DNA - Ribonuclease = breaks down RNA THE ALIMENTARY CANAL - THE MOUTH - Ingestion = intake of food - Bolus = ball of food and saliva mass - MECHANICAL DIGESTION - Jaw + teeth = chewing - Physical change of food broken into smaller pieces CHEMICAL DIGESTION - Saliva containing digestive enzymes (from 3 pairs of salivary glands) - SALIVA = contains mucus and digestive enzymes (salivary amylase) - SALIVARY AMYLASE = breaks down starch (carbohydrates) into simple sugars - Swallowing; tongue moves up and back → bolus pushed to pharynx - - 4 types of teeth (numbers for 1 row; you have 32 teeth) - INCISORS (4) = biting / cutting - CANINES (2) = tearing - PREMOLARS (4) = crushing / grinding - MOLARS (6) = crushing / grinding - THE OESOPHAGUS - EPIGLOTTIS - Flap of skin closing passage to windpipe as you swallow - Ensures food goes to stomach, not lungs OESOPHAGUS - Double layered muscular tube joining mouth to stomach - Circular muscle = O - Longitudinal muscle = || - Peristalsis - Wave of muscle constriction in oesophagus forcing bolus to move towards stomach - Successive bands of circular muscle contract to form a constriction ‘wave’ MUCUS LINING - Movement of food through oesophagus in lubricated by mucus - THE STOMACH - Main role is acting as site for food storage and breakdown - Food can stay in the stomach for ~2-8 hours - RUGAE - Series of ridges produced by folding of organ wall MUCOSA - The internal lining of the stomach - Specialised for secretion of gastric juices, which are produced by gastric glands PYLORIC SPHINCTER - Regulates transfer of chyme between stomach and duodenum (beginning of small intestine)  - Mechanical and chemical digestion in the stomach - - MECHANICAL DIGESTION - Peristalsis moving along stomach wall - 3 muscle layers; circular, longitudinal and oblique - CHEMICAL DIGESTION - Gastric juices mixing with food becomes CHYME - CHYME & Chemical Digestion - Chyme is the soupy liquid of food and stomach juices that contain HCL acid, mucus and digestive enzymes (pepsin; gastric protease) - PEPSIN = enzyme that works in acidic solutions (needs stomach acid to work - HCL = activates pepsin, kills bacteria entering stomach - MUCUS = protects stomach from acidic chyme & bacteria - SMALL INTESTINE - Main role: digestion & absorption - Size: ~6m longs → longest part of the alimentary canal - Duodenum: first part of the small intestine (25 cm) - Then jejunum, ileum - MECHANICAL DIGESTION - Peristalsis & bile - BILE - physically breaks down fat into smaller units - Secreted by liver, stored in gall bladder - Bile salts emulsify fat breaking into droplets - No digestive enzymes -  - CHEMICAL DIGESTION - Pancreatic & intestinal juice PANCREATIC JUICE INTESTINAL JUICE Secreted from… Pancreas Glands in intestine Enzymes Pancreatic amylase Intestinal amylase = Starch → disaccharides = disaccharides → simple Trypsin (pancreatic protease) sugars = proteins & polypeptides → Intestinal peptidases peptides = peptides → amino acids Ribonuclease & Intestinal lipases Deoxyribonuclease = lipids → fatty acids / = digest RNA & DNA glycerol Pancreatic lipase = lipids → fatty acids / glycerol Other functions Secreted at duodenum, helps N/A neutralise stomach acids - Large internal surface area: mucosa, villi, microvilli - ABSORPTION - Absorbs simple sugars, amino acids, fatty acids, glycerol, vitamins, minerals, nutrients and water - Absorbed through internal wall of small intestine into blood - The LARGE SURFACE AREA aids absorption - Length of small intestine - Folded mucosa - Villi and microvilli (finger-like projections on surface of each villus) - Villus are each 1mm long - Covered by single layer of cells - Absorption aided by muscular movement keeping villi moving - Villus diagram →  - What Absorption method Destination Amino Acids Active transport Blood capillaries (against concentration Simple Sugars gradient) Water Simple diffusion (with concentration Water-soluble vitamins gradient) Fatty acids & glycerol Lacteal - LARGE INTESTINE - Main role: absorption - Size: ~1.5m - Absorbs water & any remaining vitamins, minerals, nutrients - Bacteria will break down remaining organic compounds - The caecum: a pouch structure joining the small and large intestine - The lining secretes as large amount of mucus - Movement of material through the large intestine is fairly slow (18-24 hours) - RECTUM, ANUS & ELIMINATION - Faeces; the semi-solid material containing - Water - Undigested food material (cellulose) - Bacteria (⅓ faeces) - Bile pigments (brown) - Cell remains - The RECTUM is the last section of the large intestine - It has stretch receptors in the rectum trigger defecation response - The ANUS is the external opening at the end of a rectum - With the anal sphincter controlling the opening - Finally, ELIMINATION, the removal of waste products from the body DIGESTIVE PROBLEMS - Size and content of meal affects speed of material moving through alimentary canal - Larger meal = greater stretching of stomach - High protein / fat content in meal slow movement from stomach to small intestine - Alcohol / caffeine stimulate movements of stomach - CONSTIPATION - Movements of large intestine are reduced and contents remain for long periods of time - Faeces become drier and harder when water is absorbed, defecation becomes difficult - Can be caused by insoluble fibres, lack of exercise or emotional problems DIARRHOEA - Frequent defecation of watery faeces - Caused by irritation of small or large intestine, increasing peristalsis so contents move through before water can be absorbed - May be result of bacterial / viral infection BOWEL CANCER - Uncontrollable growth of cells in large intestine walls - Linked to diet (red meat), alcohol and smoking. - Being overweight, obese and physical inactivity. COELIAC DISEASE - Unable to tolerate protein = gluten (wheat, rye, barley) - Immune system respond; damaging villi - No healthy villi, nutrients can’t be absorbed, person becomes malnourished - Inherited / no cure  EXCRETION - Excretion = removal of metabolic wastes - Metabolise = breaking down of certain substances so they can be removed) - Elimination = removal of indigestible wastes, bacteria and bile pigments - WASTES - CO2, H2O, salts, urea, lactic acid, bile pigments - ORGANS INVOLVED in excretion Lungs - Excretes CO2 Liver - Metabolises + produces urea Sweat glands in skin - Excretes by-product of metabolism (salt, urea, lactic acid) Kidney - Maintain bodily fluid concentration Gut - Excretion of bile pigment in faeces. Also lose water, salts & CO2 Bladder - Storage of urine before passed outside LUNGS, LIVER, SKIN - LUNGS - Cellular respiration; metabolic process producing CO2 - Lungs breath out CO2, therefore part of excretory system - LIVER - Prepares materials for excretion - Excess proteins can’t be stored so must be removed - Proteins are either - Broken down into amino acids & reused - Lost in urine, skin, hair, etc - Broken down, used for energy - To make use of proteins as energy, the amino group (NH2) must first be removed - In a process called deamination - DEAMINATION - Removal of nitrogen from amino acids and nitrogen bases (RNA) - Nitrogen occurs in the amino part of amino acid and is toxic to the human body, so has to be removed - Nitrogen is removed to use the remaining part of amino acid to produce energy - The remaining part is converted to carbohydrates, which is broken into energy, CO2 and water - Once amino acid group is removed, it is converted into urea and eliminated in urine - - THE LIVER also - Detoxifies alcohol and many other drugs (antibiotics) - Deactivates hormones, converting them into a form that can be excreted by kidneys - Breaks down haemoglobin from dead RBC to produce bile pigments - THE SKIN - Sweat glands secrete oil & water - Dissolved in water are sodium chloride, lactic acid and urea - Some drugs (salicylic acid) also excreted by skin THE KIDNEYS - Function - Rid body of wastes, especially nitrogenous waste (urea) - Regulate pH, fluid, salt balance - Achieves this by filtering blood passing through kidneys - Waste substances removed by filtration and tubular secretion - Useful substances returned to body by selective reabsorption - STRUCTURE OF THE URINARY SYSTEM - 2 kidneys - 1 urinary bladder - 2 ureters - 1 urethra - STRUCTURE OF KIDNEYS - - THE NEPHRON - Within renal cortex and medulla; the functional unit of kidneys - Consists of glomerular capsule, renal tubule & associated blood supply - Each kidney has appropriately 1 million nephrons - Each nephron consists of renal corpuscle and renal tubule - Renal corpuscle = glomerular capsule + glomerulus - Renal tubule = PCT, loop of henle, DCT, collecting duct - Afferent arteriole = towards + efferent arteriole = away - FILTRATION - Occurs in renal corpuscle - Bowman's capsule + mass of blood capillaries - glomerulus - Blood enters kidney through renal artery - Splits off into afferent arteriole, forms glomerulus - Capillaries form back into efferent arterioles - Arteriole breaks into second capillary network; peritubular capillaries - Blood leaves kidney in renal vein - Podocytes - Specialised cells that line Bowman’s capsule - Have finger-like projections - wrap around capillaries of glomerulus - Spaces between “fingers” are filtration slits - - FILTRATION takes place specifically in glomerulus capsule - Since blood is under high pressure, the afferent arteriole is wider than the efferent arteriole - SMALL MOLECULES: - Water, glucose, amino acids, urea, sodium, potassium and hormones cross membranes of glomerulus into glomerular capsule - This fluid = filtrate - FILTERED PASSIVELY (MASS FLOW) - LARGE MOLECULES - Erythrocytes, leucocytes, proteins too large to pass through membranes, remain in glomerulus - Moved out efferent arteriole - SELECTIVE REABSORPTION - Many substances in filtrate are useful so are returned to blood via selective reabsorption - In PCT, glucose, amino acids, sodium, potassium, chloride and bicarbonate ions are selectively reabsorbed via ACTIVE TRANSPORT - Water reabsorbed by osmosis (passive) - Loop of henle responsible for reabsorption of sodium (active) - DCT; sodium reabsorbed by active transport & water by osmosis - In collecting duct, water actively reabsorbed (based on body needs) & regulated under influence of hormone ADH - ADH changes permeability of membranes of tubules - UREA - not absorbed, passed out as urine - Proximal tubule - Microvilli line proximal tubule; breathing bush border - Increases surface area for reabsorption - STRUCTURE SUBSTANCE ACTIVE / PASSIVE PCT H2O (60-70%) Passive (osmosis) Salts (60-70%) Glucose (100%) Amino acids (100%) All Active Vitamins (100%) Loop of Henle H2O (20%) Passive (osmosis) Na+ / Cl- (25%) Active DCT H2O (5%) Passive (osmosis) Na+ / Cl- (5%) Active Collecting duct H2O (5%) Passive (osmosis) - Excretion = filtration - reabsorption + secretion - TUBULAR SECRETION - Selective reabsorption removes substances from the filtrate into blood - TUBULAR SECRETION adds materials to filtrate from blood - Can be active or passive - Occurs in DCT, unwanted substances like hydrogen ions, nitrate, potassium ions, creatinine and other drugs (penicillin) are added to the filtrate - Body must maintain blood within pH range 7.4-7.5 despite our diet containing acid producing food - To raise pH of blood, tubules secrete hydrogen & ammonium ions into filtrate. They make urine slightly more acidic. - TUBULAR SECRETION - Occurs sometimes in PCT, most in DCT - Hydrogen ions - Ammonium ions - Creatinine - Toxins - Drugs - Neurotransmitters - All through active transport - URINE - Clear and transparent fluid, normally amber - Collected in bladder & eliminated through urethra - Usually contains: - ~96% water - 2% urea - 1.5% various ions (mainly sodium & chloride ions) - 0.5% other metabolic waste - OSMOTIC GRADIENT - Differences in water concentration make an osmotic gradient between filtrate inside renal tubule & tissue fluid surrounding it - Water wants to leave tubule & collecting duct - Usually can’t do this as DCT walls / collecting duct impermeable to water - Dehydration alters this - KIDNEY PROBLEMS - Kidney stones / Kidney failure - Can impair the kidneys' ability to filter waste from the blood effectively, potentially leading to complications such as pain, urinary tract infections, and even kidney damage. - Dialysis - Dialysis is a treatment often necessary for kidney failure, involving the use of a machine to perform the kidney's filtration function artificially. - Liver disease - Liver disease can indirectly impact kidney function due to the liver's role in metabolizing substances that can affect the kidneys, potentially leading to hepatorenal syndrome.