BIOLOGY TOPIC 6 HUMAN PHYSIOLOGY
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BIOLOGY TOPIC 6 HUMAN PHYSIOLOGY - Marcador
BIOLOGY TOPIC 6 HUMAN PHYSIOLOGY - Detalles
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| What is food? (2) | Substance that is consumed for nutrition to grow and reproduce solid and are large complex molecules |
| Steps of food processing? (idaae) | Ingestion digestion absorption assimilation elimination |
| Why is digestion of food molecules necessary? (2) | Small molecules are more soluble (easier to absorb) small molecules can form new products (reassembled) |
| What is the alimentary canal? (5) | All the organs which food passes through oesophagus, stomach, small + large intestine |
| What are accessory organs? (5) | Help with digestion but food doesn't pass through these organs salivary glands, pancreas, liver and gall bladder |
| What is the oesophagus? (2) | Tube connecting the mouth to stomach food is mixed w saliva to form bolus + moved down by peristalsis |
| What is the stomach? (3) | Temporary storage releases digestive juices + highly acidic environment secretes proteases |
| What is the small intestine? (2) | Absorbs nutrients has 3 sections: duodenum, jejunum + ileum |
| What is the large intestine? (2) | Absorbs water and dissolved minerals changes undigested material into semi solid feces for excretion |
| What is the salivary glands for? (3) | Releases saliva to moisten food = bolus includes parotid, submandibular and sublingual gland secretes amylase |
| What is the pancreas for? (2) | Produces digestive enzymes and hormones enzyes are released into the small intestine via the duodenum |
| What is the liver for? (3) | Converts absorbed materials into chemicals used for detoxification, metabolism, storage and bile production stores and metabolizes nutrients to regulate chemical composition |
| What is the gall bladder for? (2) | Stores and releases bile bile salts are released via the bile duct to emulsify fats |
| How is digested food moved through the body? (2) | Peristalsis: longitudinal muscles = squeezes the food through happens in the stomach and intestines (contract and relax to move the food in one direction) segmentation: circular muscles = food moves back and forth (mixes with enzymes) bidirectional |
| What is mechanical digestion? (2) | Food is physically broken down into smaller pieces chewing (mouth), churning (stomach), segmentation (intestines) |
| What is chemical digestion? (2) | Food is broken down with chemicals saliva, stomach acids, bile and pancreatic juices |
| What is a digestive enzyme? (4) | A protein that acts as a biological catalyst by speeding up the rate of a chemical reaction by lowering the activation energy they aren't changed or used up in the reaction allows digestion to happen at body temp at sufficient speeds specific molecules which bind to specific substrates |
| What are the different types of digestive enzymes? (4) | Amylase: carbohydrates = monosaccharides lipase + bile: lipid = fatty acids + monoglycerides peptidases: protein = amino acids nucleases: nucleic acid = nucleotides |
| Where are enzymes secreted from? | Mainly produced by the pancreas = secreted into small intestine salivary glands secrete amylase stomach secretes proteases |
| How are carbohydrates digested? (7) | Starch is the main polysaccharide and has 2 types: amylose: glucose monomers in linear chains amylopectin: monomers in branched chains STARCH is digested by AMYLASE = MALTOSE (Disaccharide) MALTOSE is digested by MALTASE = GLUCOSE (Monosaccharide) Glucose monomers is used for cell respiration / processed and stored in the liver as GLYCOGEN (polysaccharide) occurs in small intestine and products are transported to the liver |
| What are inactive precursors? (zymogen) | Needs a biochemical change (eg: hydrolysis reaction revealing the active site) = active enzyme. |
| How are proteins digested? (5) | Proteases are secreted as inactive precursors (zymogens) so that they don't digest the cells that made them Proteases can be activated with specific enzymes or chemical agents(low pH = acidic conditions) Starts in stomach and continues in small intestine pepsin: made and used in stomach (pepsinogen), activated by hydrochloric acid trypsin: made in pancreas (trypsinogen), activated by enterokinase in the intestine |
| How are lipids digested? (4) | Lipids are insoluble in water so they are combined with proteins to be transported in blood lipids are emulsifies with bile salts before being chemically digested by lipase components are combined w protein = chylomicrons = transported to liver liver converts chylomicrons = soluble lipoproteins |
| What is absorption? (3) | Movement of a fluid across a membrane nutrients absorbed into bloodstream within the small intestine = transported to cells by the liver Water and dissolved mineral ions are absorbed in the large intestine |
| What is assimilation? | Conversion of nutrients into a fluid or solid part of an organism |
| What are the layers of the small intestine? (5) | Serosa: protective outer layering Muscle layer: for digestive movement Outer = lOngitudinal (peristalsis) Inner = cIrcular (segmentation) Submucosa: connective tissue layer Mucosa: Inner layer for absorption |
| What are villi? (4) | Finger-like projections on the epithelial lining of the intestine absorb monomers formed by digestion + mineral ions & vitamins increase the surface area = optimize absorption rate Epithelial cells are connected by tight junctions = impermeable barrier bw body tissues and digestive juices |
| What are the key features of villi? MR SLIM | Microvilli = increases SA :Vol ratio Rich capillary network = transports digested products Single later epithelium = minimise diffusion distance Lacteals = absorb lipids into lymphatic system Intestinal glands = exocrine pits release enzymes Membrane proteins = help transport products |
| What are the different transport mechanisms for different nutrients? (4) SFSO | Simple diffusion = hydrophobic (fats) cross the hydrophobic part of the membrane. Then passes through the lacteals Facilitated diffusion = monosaccharides, vitamins and minerals are transported by channel proteins helps hydrophilic food pass through the hydrophobic part of the membrane Secondary Active Transport = glucose + amino acids are co-transported with sodium ions (Active translocation) with a transport protein Osmosis: water diffuses across membrane passively as ions and solutes move across in the small and large intestine |
| How does bulk transport work? (pinocytosis) | Endocytosis vesicles form around fluid containing dissolved materials takes less time than using membrane proteins |
| How can we model absorption? | Size specific permeability of the intestinal membrane can be modeled with dialysis tubing the tubing is impermeable to polysaccharides (starch) but is permeable to maltose = semi permeable rate of digestion can be measures by osmosis |
| Draw the digestive system | Stomach: J-shaped bag + connected to oesophagus and small intestine Liver: right-angled triangle left of stomach Bile duct (connected to gall bladder) and pancreatic duct Small intestine should be thinner than the large intestine |
| How does chewing break down food? (2) | Grinding action of teeth and the tongue pushes the food to the back of the throat travels down the throat as a bolus |
| How does churning break down food in the stomach? | Stomach lining muscles squeezes and mixes the food with digestive juices |
| How does stomach acids break down food? | Gastric glands release digestive acids = low pH (2) acidity denatures proteins and other macromolecules = digestion mucous membrane on epithelium prevents the acids damaging the gastric lining pancreas releases bicarbonate ions (alkaline) to neutralise the acids before entering the intestine |
| How does bile break down food? (3) | Made in the liver and stored in the gall bladder before released into small intestine bile salts mix with fat globules = smaller droplets (emulsification) = increases total SA for lipase activity |
| What are key features of the villi epithelium? (4) (Just Mix Monkey Poop) | Tight Junctions: impermeable barrier = keeps digestive juices separate from tissues + maintains conc gradient + 1 way movement Microvilli: increase SA = more absorption + immobilized enzymes and channel proteins on the microvilli to increase uptake Mitochondria: ATP for active transport and pinocytosis Pinocytotic vesicles: bulk transport of fluid and dissolved solutes |
| Label intestine diagram | Labelled |
| What do the hormones produced in the pancreas do? (4) | Produces insulin and glucagon which is released from the endocrine glands regulates the conc of glucose in blood insulin lowers blood glucose levels = increases glycogen synthesis and storage in liver glucagon increases blood glucose levels = limits synthesis and storage |
| Describe the method for measuring meniscus levels (5) | Dialysis tubing attached to gunnel and filled with starch solution (control) another tubing is attached to a thistle funnel with starch and amylase solution (Experiment) placed in beakers of water over time water moves into tubing by osmosis (towards solute) = water line rises (meniscus) amylase tube will have less solute bec starch is being digested = lower meniscus |
| Describe the method for measuring maltose diffusion | Dialysis tubing filled with starch and kept in a beaker of water (control) second tubing filled with starch and amylase and kept in a beaker of water (Experiment) amylase in 2nd tube will digest the starch into maltose = small enough to diffuse out into beaker presence of amltose can be tested with Benedicts test |
| What is the role of a pacemaker? | It causes the cardiac cells to act in unison to cause a sinus rhythm |
| What are the functions of the cardiovascular system?(3) | Circulates important materials such as oxygen, nutrients and water removes waste products maintains a constant body temp and transports hormones |
| What are the components of the cardiovascular system? (3) | Blood = fluid medium where materials are transported vessels = functions as a network which move blood through Heart = acts as a pump to drive the movement of blood through the vessels |
| Who discovered the circulatory system? | William Harvey |
| What did William Harvey find out about the circulatory system? (3) | Major vessels (Arteries and veins) are part of a single, connected network The heart works as a central pump (arteries = away from heart ; veins = return to heart) Blood flow is continuous (not consumed) and unidirectional (with valves) |
| Draw a basic labelled heart (5) | 2 atria and 2 ventricles |
| Why does the left side have a thicker muscular wall? | Myocardium = has to pump blood further than the right side as it contains oxygenated blood |
| What does the left and right side of the heart do? | Left side: oxygenated blood around the body (systemic circulation) = thicker muscular wall (myocardium) as it has to pump blood further than the right side Right side: deoxygenated blood to the lungs (pulmonary circulation) |
| What are ventricles in the heart? (3) | Pumps, remove blood from the heart at high pressures from the arteries left ventricle = bicuspid valve + aortic valve right ventricle = tricuspid valve + pulmonary valve |
| What is the atria (atrium) in the heart? (3) | Reservoirs, blood returning to the heart is collected in veins and passed onto ventricles left atrium = bicuspid and aortic valve right atrium = tricuspid and pulmonary valve |
| What are the 4 valves in the heart? | Atrioventricular valves (between atria and ventricles) – bicuspid valve on left side ; tricuspid valve on right side Semilunar valves (between ventricles and arteries) – aortic valve on left side ; pulmonary valve on right side |
| What are the names of the veins and arteries attached to the heart? Which part of the heart are they attached to? (5) | Vena cava (inferior and superior) = right atrium and returns deoxygenated blood pulmonary artery connects to the right ventricle to send deoxygenated blood to the lungs pulmonary veins goes into the left atrium with oxygenated blood from the lungs aorta goes from the left ventricle to send oxygenated blood around the body veins = atriums artery = ventricles |
| What do vessels do? | Transport blood in the cardiovascular system |
| What are the 3 different types of blood vessels? | Arteries = transports blood from heart at high pressure (thick walls) Capillaries = exchanges material bw blood and tissue (single endothelial layer) SMALLEST Veins = transports blood back to heart at low pressure (thin walls) |
| How are the vessels connected? (4) | Arteries branch into arterioles which form capillaries = decreases pressure as the total volume increases the branching into capillaries makes sure blood is moving slowly capillaries is the smallest vessels and connects the arteries and the veins capillaries pool into venules which becomes veins |
| What is the function of the arteries? | Moves blood at high pressure from the ventricles to the body |
| How are arteries specialized? (4) | Narrow lumen compared to the wall thickness - high blood pressure thick wall with outer layer of collagen = stops artery from rupturing from high pressure inner layer of muscle + elastic fibres = maintains pulse flow don't have valves bec backflow isn't possible with high pressures |
| What is blood and what does it do? (what made up of?) | The fluid medium which materials are transported around the body in with blood vessels. It transports things like dissolved materials, electrolytes and proteins has 3 types of blood cells: red blood cells = transports oxygen (erythrocytes) white blood cells = fights infections (leukocytes) platelets = clotting (thrombocytes) |
| What materials are transported in the plasma? (NACHO UH?) | Nutrients (glucose, amino acids) Antibodies (immunoglobulins) Carbon Dioxide (respiratory waste) Hormones (chemical messengers) Oxygen (respiration) Urea (nitrogenous waste) Hear (thermoregulation) |
| How would you describe the way blood flows through the arteries? | Repeated, rhythmic surges = pulses |
| How do the arteries maintain a high blood pressure between pump cycles? | With the muscle and elastic fibers |
| How do muscle fibres help maintain a high blood pressure in arteries? (3) | Rigid arterial wall for high blood pressure without rupturing to narrow the lumen = increase pressure bw pumps maintains blood pressure throughout cycle |
| How do elastic fibres help maintain a high blood pressure in arteries? (3) | Arterial wall stretches and expands with pulse flow through lumen = pressure releases on arterial wall is returned to blood when artery becomes normal size again (elastic recoil) = pushes blood forwards + maintains pressure |
| What do capillaries do? | Material exchange between blood and tissues |
| How are capillaries specialized? (3) | Very small lumen = only a single red blood cell at a time transports blood at low pressure = maximizes material exchange walls are a single endothelial cell layer, surrounded with a basement membrane = minimizes diffusion distance and is permeable extensive |
| How are capillary walls different in different locations? (3) | Continuous w endothelial cells, held together with tight junctions = limits absorption of large molecules Absorption tissues (kidneys, intestine) = fenestrated (many pores) permeable to large molecules (in liver) = sinusoidal , open spaces between cells |
| What materials enter and exit blood in capillaries? (4) | Materials that exit blood = nutrients and oxygen (cell respiration) materials that enter = carbon dioxide and urea (waste products |
| How does blood flow through capillaries? (4) | Very slow at very low pressure = max material exchange extensive branching and narrower lumen reduces the high BP from arteries high hydrostatic pressure at arteriole end = good materials to exit (O2) low hydrostatic pressure at venule end = bad materials to enter (CO2) |
| What do veins do? | Carry blood back to the heart at low pressure |
| How are veins specialized? (4) | Wide lumen thin walls bec of low BP, no elastic recoil valves to stop backflow and pooling of blood can be compressed by skeletal muscle contraction which allows blood flow against gravity |
| How do valves prevent backflow? Where is it found? | Causes unidirectional blood flow which stops blood pooling in veins and heart |
| How does blood flow through veins? (2) | Travels at low pressure which makes it difficult to move against gravity has one way valves to maintain circulation of blood and prevent backflow |
| How do veins transport blood against gravity? (2) | They are compressed by contractions of skeletal muscles which causes blood to flow veins run parallel to arteries and can be compressed by arterial bulges created by a pulse |
| How do you identify the 3 different blood vessels under a microscope? | Arteries = thick walls with 3 distinct layers small lumen veins = thin walls and wider lumen capillaries = small and not detected under same magnification as arteries and veins |
| How does the heartbeat occur? | Started with a group of specialized muscle cells in the right atrium |
| How is the contraction of the heart myogenic? what does myogenic mean? | Myogenic means that the signal for cardiac compression comes from the heart muscles itself (cardiomyocytes) not from brain signals |
| What are the muscles that contract the heart called and where is it located? | Cariomyocytes are in the wall of the right atrium = the cluster of cells are collectively called the sinoatrial node |
| How does the sinoatrial node act as a primary pacemaker? (4) | It controls the rate at which the heart beats causes around 60 - 100 contractions / minute if it fails then a secondary pacemaker (AV node) maintains the contractions at 40-60 bpm the last tertiary pacemaker (bundle of his) can do contractions at 30-40 bpm |
| What would happen if there was no pacemaker? | Fibrillation = the cardiac cells would act independently = irregular and uncoordinated contractions |
| What is the role of a pacemaker? | It causes the cardiac cells to act in unison to cause a sinus rhythm |
| How does the sinoatrial node stimulate contraction? (4) | It sends out an electrical signal and is spread through the walls of the atria and then the walls of the ventricle = stimulates contraction of myocardium (heart muscle tissue) the impulse causes the atria to contract and stimulates another node between the atrium and ventricle 2nd node = atrioventricular node (AV) sends signals down the septum via Bundle of His Bundle of His supplies nerve fibres (purkinje fibres) in the ventricular wall = ventricular contraction |
| How does the electrical conduction cause 2 beats? (2) | Due to the delay between the atrial and ventricular contractions this delay causes the ventricles to fill with blood following the atrial contractions = maximizes blood flow |
| How can the heart rate be increased or decreased? (4) | Hormonal signalling = sustained slower changes nerve signalling = quick changes changes to blood pressure levels or CO2 concentrations |
| How does nerve signalling work? (5) | Pacemaker is under involuntary control from medulla oblongata (Brain stem) 2 nerves that are connected to the medulla regulate the heart rate sympathetic nerve = releases NT noradrenaline = increase heart rate parasympathetic nerve = releases NT acetylcholine = decrease Heart rate triggers quick changes |
| What are hormones? | Chemical messengers that are released into the bloodstream to act on target sites |
| How do hormones change heart rate? example(2 names) | HT can have a sustained increase to prep for physical activity w/ hormonal signalling adrenaline (epinephrine) is released by adrenal glands (Above kidney) which increases HT by activating the same chemical pathways as the NT noradrenaline |
| Describe the cardiac cycle (sis , diarrhea) (4) | A heart beat is made up of contraction (systole) and relaxation (diastole) contraction = increases P in atria and ventricles = blood flows from area of high pressure to low pressure Systole: when ventricles contract, AV valves close to stop backflow into atria = blood into arteries (1st sound) bicuspid and tricuspid valves close Diastole: when ventricles relax, semilunar valves close = stops backflow into ventricles = blood into arteries (2nd sound) blood flows out of the heart through the arteries (pulmonary and aortic arteries) |
| Describe what happens during systole in the cardiac cycle? (5) | Blood flows into atria + ventricles bec low P bec low V of blood when ventricles is full = atria contacts = increase P in atria to force all blood into ventricles When ventricles contract AV valves close to stop backflow = first sound P increases in contracting ventricles = isovolumetric contraction when ventricular P > BP in aorta = AV opens = blood released in aorta |
| Describe what happens during diastole? (2) | As bllod exits, ventricular P decreases = when below Aortic p the Aortic valve closes to stop backflow (2nd sound) when VP is below AP the AV valve opens - blood can flow from atria to ventricle |
| Why is aortic pressure always high? | Because muscles and elastic fibres in artery wall maintains BP |
| What can happen to the coronary arteries? What does it do? | Supplies the cardiac tissue with oxygen and nutrients = if it becomes blocked = part of the heart will die and stop working |
| What causes coronary occlusion? | Atherosclerosis = hardening + narrowing of arteries bec of cholesterol |
| Describe the process of atherosclerosis developing? (6) | 1) fatty deposits (Atheromas) develop in arteries = reduces lumen size (stenosis) 2) restricted flow = increases P in artery = damaged arterial wall 3) damaged region repaired with fibrous tissue = reduces elasticity of the wall 4) as the smooth lining is degraded = lesion forms (atherosclerotic plaque) 5) if it ruptures = blood clotting starts = forms thrombus (blood clot in vessel) 6) if thrombus is moved = embolus = blockage in a smaller arteriole |
| What can happen because of coronary occlusion? (3) | Blood clots = CHD in coronary arteries myocardial tissue needs nutrients from coronary arteries to function so when completely blocked = acute myocardial infarction = heart attack |
| How is blockage of coronary arteries treated? (3) | By-pass surgery creating a stent (tiny tube that can be placed ina vessel to hold it open Balloon angioplasty = balloon inserted in narrow area nad inflated to flatten plaque = artery widened = blood flow improves |
| What causes CHD? A GODDESS (8) | Age = vessels beocme less flexible with age Genetics = hypertension predisposes individuals Obesity = additional strain Diseases = increase risk (diabetes) Diet = rich in saturated fats, salts and alcohol increase risk Exercise= lack of it will increase risk Sex = males are more likely to develop it bec of lower estrogen levels Smoking = nicotine causes vasoconstriction = increases BP |
| Describe the flow of blood as it completes 1 full circulation | Blood enters the heart through the inferior and superior vena cava, to carry deoxygenated blood into the right atrium. The blood the flows into the right ventricle through the open tricuspid valve and once the ventricles are full the valves are closed to prevent backflow of blood. The blood leaves through the pulmonic valve into the pulmonary artery into the lungs to be oxygenated. The pulmonary vein carries oxygenated blood from the lungs into the left atrium. The oxygenated blood goes into the left ventricle. The blood leaves the heart through the aorta and to the body. |
| What are the features of an alveolus? | Pneumocytes 1 and 2 pulmonary surfactant wall of alveolus spherical rich capillary network wall of capillary |
| How is the alveolus adapted for diffusion (4)? | Fluid makes it easier for gases to dissolve into 1 cell thick wall spherical = maximises SA rich capillary network = increases gas exchange |