Animal Structure & Function PDF

Animal Structure & Function BY: DR. CHABROL MODIFIED BY: NATHANYA SMITH Structure & Function Anatomy- study of the structure Physiology – study of function Characteristics of Life ▪Movement – change in position; motion ▪Responsiveness – reaction to a change ▪Growth – increase in body size ▪Reprod...

Animal Structure & Function BY: DR. CHABROL MODIFIED BY: NATHANYA SMITH Structure & Function Anatomy- study of the structure Physiology – study of function Characteristics of Life ▪Movement – change in position; motion ▪Responsiveness – reaction to a change ▪Growth – increase in body size ▪Reproduction – production of new organisms and new cells ▪Respiration – obtaining oxygen, removing CO2 & releasing energy from foods ▪Differentiation – unspecialized to specialized ▪Digestion – breakdown of food substances to simpler forms Characteristics of Life ▪Absorption – passage of substances through membranes and into the body ▪Circulation – movement of substances in body fluids ▪Assimilation – changing of absorbed substances into chemically different forms ▪ Excretion – removal of waste produced by metabolic reactions Maintenance of Life ▪ Life depends on five environmental factors: ▪ Water ▪ Food ▪ Oxygen ▪ Heat ▪ Pressure Levels of Organization ▪ The human body can be seen as a hierarchy of increasing size and complexity. ▪ Starts at the level of atoms and molecules and ends at the level of the entire organism. Levels of Organization Cells are made organelles and other components which are made of macromolecules. Cells form tissues Tissues form organs Organs form systems Systems form whole body  Cells ▪Cytology - study of cells and their function. ▪Basic unit of life. ▪Nothing smaller than a cell is considered alive. ▪All tissues and organs in the body are formed by cells.  Typical Animal Cell Cell Specialization ▪Multicellular organisms have cells specialized for specific functions. ▪Cells can “concentrate” on one function and rely on others to meet their requirements. ▪Cells will have a cell membrane, nucleus and cytoplasm but their shapes are different. ▪Skeletal muscle cells need oxygen and glucose for cellular respiration. ▪ Cells in the gut are specialised to digest food and provide glucose. ▪ Red blood cells are specialised to take oxygen from the lungs and transport it to muscles. ▪ Red blood cells – make up blood, which is moved around the body by the heart and blood vessels. ▪ The heart is made of cardiac muscle fibres, which differs from skeletal muscle cells which allow is to move. Neuron Tissues Histology- the study of tissues. A group of similar cells working together forms tissues. Four types of tissue: ▪ Epithelial- skin, hair, fingernails ▪ Connective- cartilage, bone, blood ▪ Muscle- limbs, heart, stomach ▪ Nervous- brain, spinal cord, nerves  Epithelial Tissue Structure ▪ cells in epithelial tissue are tightly packed together. ▪ Epithelial tissue covers all body surfaces, lines body cavities & hollow organs. Function ▪ Protection (skin) ▪ Secretion (glands) ▪ Absorption ( small and large intestines) ▪ Excretion (kidney tubules) ▪ Sensory reception. ▪ Gas exchange (alveoli of the lungs) Connective Tissue Structure- ▪ Made up of extracellular matrix; ground substance, fibers & connective tissue cells. Function- ▪ Supports organs & cells ▪ Medium for exchange of nutrients & waste between the blood and tissues ▪ Protects against microorganisms ▪ Repairs damaged tissues ▪ Stores fat – adipose tissue Muscle Tissue Three types of muscles tissue- 1. Skeletal- attached to bones 2. Smooth- intestines, blood vessels, uterus 3. Cardiac- heart only Skeletal Muscle Structure- ▪ A form of striated muscle, voluntary control. ▪ Composed of 100s- 1000s of muscle fibers and wrapped in connective tissue. ▪ Each muscle fiber is a single cylindrical muscle cell. Function- ▪ maintain posture ▪ stabilize bones and joints ▪ control internal movement ▪ generate heat Smooth Muscle Structure- ▪ Involuntary muscle, non-striated ▪ Consists of narrow spindle-shaped cells with a centrally located nucleus. ▪ Tapered at the end. ▪ Contracts slowly and automatically Function- ▪ Contraction ▪ Peristalsis Cardiac Muscle ▪Structure- ▪ Branched and striated involuntary muscle ▪ Single nucleus ▪ Joined together by intercalate discs Function- ▪ Contraction & relaxation of the heart  Nervous Tissue Structure- ▪ Elongated cells with branches at the end ▪ CNS- brain, spinal cord ▪ PNS- nerves outside the CNS Function ▪ Nerve cells- conduct electrical impulses ▪ Glial cells- support, nurture and protect the neurons Systems Integumentary System ▪Prevents water loss ▪Protects against invasion by infectious organisms ▪Synthesizes vitamin D ▪Blocks UV light ▪Regulates body temperature Organs- Hair Skin Nails Sweat & sebaceous glands Musculoskeletal System ▪Supports & protects body ▪Forms RBCs ▪Stores minerals ▪Produce movement Organs Bones Joints Muscles  Cardiovascular System ▪Pumps blood to transport nutrients, O2 and waste. ▪Humans have trillions of cells; simple diffusion may work for smaller multicellular organisms and unicellular organisms but is inefficient for larger organisms. Organs Heart Arteries Veins Blood (liquid connective tissue)  Lymphatic System ▪Transports clean fluids back to blood ▪Drains excess fluids from tissues ▪Removes debris from cells of body ▪Transports fats from digestive system Organs Lymph nodes Lymphatic vessels Spleen Thymus gland Tonsils  Gastrointestinal System ▪Ingestion, digestion & absorption of food. ▪Excretion of waste. Organs ▪Oral cavity Pharynx ▪Esophagus Stomach ▪Small intestine Colon ▪Liver Gallbladder ▪Pancreas  Respiratory System ▪Conduction of air in and out the body. ▪Gas exchange. ▪Cleans, humidifies and warms incoming air. ▪Protects airways by mucociliary escalator, traps particles and debris ▪Vocalization. Organs Nasal cavity Pharynx Larynx Trachea Bronchial tree Alveoli Lungs Urinary System ▪Eliminates waste ▪Maintains homeostasis of minerals in ECF ▪Regulates acid-base balance ▪Controls ECF volume Organs Kidneys Ureters Bladder Urethra Female Reproductive System ▪Produces eggs ▪Carries baby Organs Ovaries Fallopian tubes Uterus Vagina Vulva Clitoris Labia Breast Male Reproductive System ▪Produces sperm Organs Testes Epididymis Vas deferens Penis Seminal vesicles Prostate gland Bulbourethral glands Endocrine System ▪Release of hormones into bloodstream. ▪Regulates metabolic activity Organs Pituitary gland Pineal gland Thyroid gland Parathyroid gland Thymus gland Pancreas Adrenal glands Ovaries & testes  Nervous System ▪ Receives and transmits sensory information. ▪Coordinates all the body’s voluntary and involuntary actions. ▪Can be classified based on anatomy ▪ Central nervous system (brain and spinal cord) ▪ Peripheral nervous system (nerves outside the CNS) ▪Can be classified based on function ▪ Sensory component Electrical impulses sent to the CNS ▪ Motor component ▪ Impulses transmitted from CNS to different parts of the body Organs Brain & spinal cord- CNS Nerves- PNS  Special Senses- Eye ▪Collects and focuses light on the retina and forms images. ▪ Rods and cones are highly specialized sensory cells located in the retina at the back of the eyeball. ▪ Rods detect low light intensities ▪ Cones are only stimulated in higher light intensities. ▪ Works with the brain to interpret the information. Organ Eyes Special Senses- Ear ▪Hearing and balance. ▪Sound-sensitive cells in the inner ear receive sound and nerve cells transmit that information for interpretation. Organ Ears  Special Senses- Taste & Smell ▪Ability to sense chemicals, so taste and olfactory (odor) receptors are chemoreceptors. ▪ Taste receptors are found in tiny bumps on the tongue called taste buds. ▪Taste receptors make contact with chemicals in food through tiny openings called taste pores. ▪Separate taste receptors for sweet, salty, sour, bitter & umami. Organ Tongue Special Senses- Smell ▪Olfactory receptors line nasal passages. ▪Millions of olfactory receptors present which sense chemicals in the air. ▪Receptors can sense hundreds of different odors & send signals to the olfactory bulb in the brain. Organ Nose  General Senses- Touch ▪Ability to sense pain, temperature, vibration, pressure and other tactile stimuli. ▪Stimuli are detected by mechanoreceptors, thermoreceptors & nociceptors all over the body. Organ Skin  Review ▪Compare and contrast human anatomy & physiology. ▪Summarize the hierarchical organization of the human body. ▪Define tissue and identify the 4 tissue types. ▪What is an organ? Give 3 examples of organs. ▪Define organ system and name 5 organ systems. ▪Which organ system secretes hormones? ▪Which organ system’s function provides structure to the body & protects internal organs? ▪Organs consist of one or more tissue types. True or False? ▪What are the special senses? Questions? The Gastrointestinal System Nathanya Smith, MSc Overview Ingestion Mechanical Digestion Chemical Digestion Food is Absorbed into the Bloodstream Food is Assimilated into Cells Waste is Eliminated from the body  Ingestion The consumption of food. Several hormones associated with feeding behavior. Glucagon - breaks down glycogen into glucose. Insulin Ghrelin Leptin Hormones are chemical Cholecystokinin – increases pancreatic enzyme secretion messengers. Allows the body to ADH & aldoster one – trigger thirst, increase fluid consumption communicate with distant cells and tissues. Digestion The process by which large food molecules are broken down into smaller ones. There are 2 forms, which work together. 1. Chemical digestion – breaking of chemical bonds. Enzymes 2. Mechanical digestion – does not inv ol v e the breaking off chemical bonds. C h e wi ng C h u r n i ng i n t h e s t o ma c h E m u l sif i ca t io n o f f a t s i n t e st in e  The Anatomy Gastrointestinal tract M uscular tube Mo u th Small Large Rectum & Mouth Esophagus Stomach Intestine Intestine Anus E s o p h agu s S to ma c h S ma l l i n te s ti n e s L a r ge I n te s ti n e s R e c tu m An u s Accessory organs P a n c re as , g a l l b l a dde r, L i v e r  Mouth Bite pieces of food, chop, crush, grind food into smaller pieces. Chewing increases surface area so that it is exposed to saliva and gastric, chemical digestion is faster if particles are smaller. This is called mastication. Mouth – Teeth We have 2 sets of teeth in our lifetimes. 1. Deciduous (milk) teeth 1. Replaced around 6 yo. 2. Permanent teeth Mouth - Teeth Crown – exposed to mouth cavity Enamel – Very hard shiny material 96% salts and calcium phosphate Dentine – main tooth substance, yellowish/ivory, like bone but harder; fine canals with cytoplasm passing through – softer than enamel Mouth - Teeth Pulp Cavity – contains tiny blood vessels. Nerves. pain and sensory receptors, tooth forming cells. Cement – Bone like, fixes tooth in socket Mouth- Teeth We have 4 types of teeth in adulthood. 1. Incisors – biting and grinding 2. Canines – piercing and tearing 3. Premolars – grinding and chewing 4. Molars- grinding and chewing Mouth Tongue helps mixes food with 3 pairs of the saliva glands in the head. Smell, taste, sight of food, signals the secretion of saliva. Saliva has salivary amylase. Saliva also contains mucus, to lubricate food. pH is 7.0. optimum for amylase.  Swallowing Piece of food becomes a bolus. Chewing and tongue movements push food toward the back of your mouth – complex. Some movements are involuntary; controlled by the medulla in the brain. Peristalsis begins in the pharynx to propel food toward the esophagus.  Esophagus Muscular tube connecting pharynx to the stomach. Transfer food by peristalsis from mouth to stomach, by gravity and peristalsis. Peristal s i s , muscl es in the gut work together to produce wav e l ike contracti ons. Circular muscles contract , making the l umen smaller, propel l ing food forward. Circular muscles will relax , al l owing the canal wal l to expand.  Enteric Nervous System Neurones present in the walls of the gastrointestinal tract trigger peristalsis. The enteric nervous system consists of Meissner’s and myenteric plexi – a network of neurons.  Stomach Stomach, highly muscular sac. Has a thick ring of muscle where it joins the small intestine = pyloric sphincter. Stomach wall muscles, relax and contract, squeezing and churning eaten food, with enzymes and mucus (gastric juice) The food mixture with gastric juices is called chyme.  Stomach Characteristic rugae (gastric folds)- longitudinal folds in stomach lining. Stomach cells will secret different substances to aid in digestion. All these cells are located in pits – gastric pits Goblet cells wil l secrete mucus Some cel l s wil l secrete pepsin – enzyme breakdowns proteins to polypeptides Some cel l s wil l secrete HCl – acidic pH of stomach Know: Regions of the stomach Stomach Cells in the stomach, secrete HCl and the protease, pepsin. HCl helps protects us from infection, killing most of bacteria we eat drink Low pH in the stomach, will denature any salivary amylase in food.  RECALL Enzymes: pH Enzymes have an optimum pH. Optimum pH may be different depending on the enzyme. The pH is the stomach is very acidic compared to the intestinal pH which is more basic/alkaline. Small Intestine Major site of digestion. Approximately 5-6m long. Quite narrow. Separated into different parts. 1. Duodenum 2. Jejunum 3. Ileum  The Duodenum The pyloric sphincter muscles will relax to allow the food from the stomach to enter the duodenum. Food entering the duodenum is mixed with 1. Pancreatic juice from pancreas. 2. Bile from the liver.  The Duodenum Enzymes have to secreted into the duodenum, so digestion can continue. The enzymes come from another organ called the pancreas. Pancreatic juice enters duodenum via the pancreatic duct. The Duodenum Pancreatic juice can contain. ✓ Pancreatic amylase ✓ Proteases - Trypsin and chymotrypsin ✓ Lipase Remember chyme is acidic, the stomach is adapted for acidic conditions but not the duodenum. Pancreatic juice neutralises the acidic pH, because it also contains sodium bicarbonate (NaHCO 3 ) – which is basic. The Duodenum Bile is produced in the liver. Stored in the gallbladder. Food(fatty) entering the duodenum, signals the gallbladder to release bile. Bile is also alkaline , helping to neutralise the acidic chyme from the stomach, pH is around 8.0.  Duodenum and Ileum Most digestion takes place here. They are broken down so they can be absorbed, here. Absorption is the action of food moving from inside the intestine from to the bloodstream and lymph vessels.  Bile Has a Special Purpose Bile, is really made of bile sal ts. Bile is a green -yellow Bile is needed for the absorption of fats. Bile sal ts help change l arge l ipid droplets into smaller ones in a process called emulsification. Bile Emulsification is not chemical digestion. It just makes the lipid droplets smaller, lipase can then easily catalyse them. Bile flows into the duodenum via the bile duct. Ileum Also secretes other enzymes – these complete digestion of starches and proteins. Sucrase Maltase Lactase Peptidase Large Intestine (Colon) Approximately 1m long Divided into the sections Appendix Cecum Colon Rectum  Colon Site of water absorption. Many bacteria live here , and may digest some of the remaining food. This is where some vitamins K and B group are made. Help protect against some harmful bacteria. Not all food eaten is digested and absorbed, usually fibre, dead cells and bacteria. Most of the water absorbed in small intestine, remainder absorbed here.  Large Intestine Food enters large intestine at junction where cecum and appendix is located. Water and ions are absorbed here. Stores feces in the rectum. Its lumen is wider than the small intestine.  Colon As more water is absorbed undigested food becomes solid. The solid waste/faeces is stored in the rectum until passed out through the anus. Typically a meal can take 24 -48 hrs to digest. Anal Canal Faeces pass out the body.  Absorption Food has to be broken down first before it’s used by the body. Smaller food molecules can then be absorbed into the body. Chemical and mechanical digestion is done first. Teeth – mastication Enzymes Lipid emulsification Churnin g in Stomach Food is Broken Down  Absorption Absorption is the movement of digested food molecules into the blood or lymph. Monosaccharides, amino acids, fatty acids and glycerol need to pass through epithelial cells of small intestine , by diffusion or active transport. Absorption mainly occurs in the small intestine. The small intestine structure, is especially adapted for absorption.  Recall - Cell Specialization Cells Tissues organs organ systems Remember cells are specialized for certain functions. Epithelial cells are usually found on surfaces and l ining the internal structures. Ci l i a te d e p i th e l i um S q u amo u s e p i th e l i u m Ne r v e c e l l s a r e f o r tr a n s mi ttin g e l e c tr i c a l i mp u l s e s. S p e r m a n d e g g s c e l l s a r e f o r r e p r odu c tio n. Mu s c l e s c e l l s a r e f o r p r o mo ti ng mo v e me n t.  Adaptations of Small Intestine Very large surface area. The small intestine is very long (5 -6m l ong). The l ining is only one cell thick , so that food mol ecules can easily pass through. I t has villi and microvilli. Cell membranes have carrier proteins for active transport. Absorption The length of small intestine, gives time for digestion to be completed. Monosaccharides, amino acids, minerals, water, vitamins are absorbed into the blood capillaries. Products of lipid breakdown are absorbed into lacteals (lymph vessels) Absorption Small intestine, specifically the ileum is the main area for absorption of nutrients. The epithelial lining has many villi.  Villi Singular villus. The inner lining of the small intestine is folded. The folds form finger -like projections called villi. Villi increases the surface area for absorption. The larger the surface area the faster absorption occurs.  Villi Each villi will be accompanied by blood vessels and lymph vessels. Villi, the folded epithelium is only one cell thick. The cells of the villi, have microvilli. Microv il l i are projecti ons of the cel l surface membrane. Microv il l i al so add more surface area.  Digested food enters the capillar ies and the lacteals in the v il l i. Absorption The absorbed food mol ecul es are transported to the l iv er. The hepatic portal vein transports food from the small intestine to the liver quickl y. Fatty acids and gl ycerol transported more sl owl y, v ia l ymph v essel s.  Liver: Assimilation The bl ood going to the l iv er v ia, the hepatic portal vein is now rich in food mol ecul es. Liv er wil l process the digested food. Liv er cel l s can make protei ns from amino acids. Breakdown potential l y toxic substances , e.g. al cohol , paracetamol. Stores some v itamins , l ike A , D and K. Remov e excess nitrogen. Remov es toxins, pestici d es , carcinogens and other poisons conv erting them to l ess toxic forms.  Assimilation Assimilation is the use of the digestion products by the body. Liver plays a role in assimilation. Amino acids to make proteins. Storage of glucose as glycogen. Fatty acids and glycerol as triglyceride, and stored about the body.  Assimilation Some amino acids will pass through the liver and go to the body cells. I mportant for growth and repair, making of proteins, enzymes, fibrous proteins like collagen in the skin. Excess amino acids or unused amino acids l eads to excess nitrogen. Nitrogen is conv erted to ammonia(tox ic) then converted to urea (non toxic). Assimilation Glucose will be carried around the body to be used in cellular respiration. Excess glucose is stored in liver and muscles as glycogen. One of the body’s mechanisms to regulate blood sugar. Assimilation  Egestion Egestion is the process by which faeces passes through the anus. Not be confused with excretion. Question 1 Bile is made in ________ and stored in the _________. A. pancreas, gallbladder B. Gallbladder, stomach C. Liver, gallbladder D. Gallbladder, liver Question 1 Bile is made in ________ and stored in the _________. A. pancreas, gallbladder B. Gallbladder, stomach C. Liver, gallbladder D. Gallbladder, liver Question 2 Place the alimentary canal in order. Oropharynx, Jejunum, anus, mouth, ascending colon, splenic flexure, rectum, ileum , sigmoid colon transverse colon, duodenum, stomach, laryngopharynx esophagus, hepatic flexure, descending colon, ileocecal junction, nasopharynx, cecum Question 2 Place the structures of the digestive system in the correct order order. Small intestine Mouth Esophagus Stomach (duodenum, jejunum Ileocecal junction and ileum) Cecum Right colic flexure Large Intestine Ascending colon Transverse colon (hepatic flexure) Left colic flexure Descending colon Sigmoid colon Rectum Anus (splenic) Question 3 Based on question 2, label all parts of the digestive system.  To Do List Differentiate between mechani cal and chemical diges ti on Define ingesti on Unders tand the importance of bil e and pancreati c juice, their contents and source. Know the anatomy of the diges tiv e system from mouth to anus. Regions of the stomach What is the rol e of the l iv er, pancreas and gal l bl adder. Draw l arge annotated drawi ng of v il l i. Difference between absorpti on and assimil ation. What is the l iv ers rol e in assimil ati on. Make a tabl e of the diges tiv e enzymes , their substrates and the resul ti ng diges tiv e products. Balanced Diet N A T H A N Y A S M I T H  Nutrient A substance in food that provides benefit to the body. Macronutrient Major nutrients, the organic compounds we eat Key Terms to in large amounts. Know Carbohydrates Fats Proteins Balanced Diet A balanced diet provides all energy and nutrients that a person requires for their immediate needs.  Deficiency Inadequate amount of a nutrient. Key Terms to Know We are what we eat. Organisms are made up of many different chemicals. Most of our bodies are made of water (70-80%). Recall the make up of cytoplasm. We are also made of carbohydrates, proteins and fats.  What makes a balanced diet? Energy Essential amino acids Essential fatty acids Vitamins Minerals Water Fibre (roughage) Why We Eat? Carbohydrates, lipids, fats provide the energy we need for work. Food provides the building blocks for organic substances. Amino acids Proteins Fatty acids, Fats glycerol Simple sugars/ Carbohydrates monosaccharides Food provides vitamins and minerals. Is carbohydrate present? We can use chemical tests to see if carbohydrates are present. Test for starch? Positive test is blue black colour change in presence of starch. Reducing Sugars Reducing sugars are the monosaccharides and the disaccharides ALL disaccharides test positive with Benedict’s solution except sucrose. We use Benedict’s solution to test to see. A positive test for reducing sugars. Colour changes from blue to green, orange or red. A negative test for reducing sugars. Reducing Sugars Non-Reducing Sugars The non reducing sugars include sucrose. The reagents used are HCl (hydrochloric acid), sodium hydroxide (NaOH) , Benedict's solution. A negative test for reducing sugars. There’s no colour change and solution remains blue A positive test for non reducing sugars. Colour changes from blue to green, orange or red. Non reducing sugar test Non-reducing sugar test Why do we boil sucrose with HCl. Sucrose = glucose + fructose This breaks the bonds between the glucose and fructose. The breaking of this bond is called hydrolysis. HCl is a catalyst. NaOH neutralises the HCl.  Macronutrients Amino acids can be separated into 2 groups. Essential amino acids Non-essential acids Essential amino acids must come from the food we eat, our bodies cannot make them. There 8-10 essential amino acids. Non-essential amino acids can be made in the body. Macronutrients Similarly, essential fatty acids cannot be made from anything else in the body, the must come from our diet. Essential = must come from diet  Vitamins and Minerals Also known as micronutrients. They do not provide us with energy. They are only needed in tiny quantities. Vitamins are complex organic substances. Minerals are inorganic and are often absorbed as ions. Recall, ions are molecules with a small electrical charge. E.g. Na+ , Cl- Vitamins Vitamins are needed to keep us healthy. They each have a role to play to keep the body functioning. Vitamins are divided into 2 groups. Lipid soluble vitamins Water soluble vitamins Solubility of vitamins determines the food it’s found in. Vitamins Lipid (fat) soluble vitamins. Vitamin A Vitamin D Vitamin E Vitamin K Vitamin A Found in butter, milk, eggs (yolk), liver, fresh vegetables (carrots), cod liver oil, chilli powder, sweet potatoes, Needed to make the pigment, rhodopsin in the rod cells of the retina in the eye. Needed to help gas exchange surfaces healthy. Deficiency – night blindness, unable to see in dim light  Vitamin D Found in liver, butter, cheese, sunlight on skin, milk, fish oil. Helps calcium and phosphate to be absorbed from food. Calcium and phosphate are the main components of bone and teeth. Deficiency – disease called rickets. Rickets is softening and weakening of bones. Vitamin E Found in green vegetables. Vitamin E is an antioxidant, it helps protect cell membranes from chemical damage. Deficiency – cell membranes are not protected and can break down easier. Red blood cells – will break down causing anaemia. Nerve cells can break down as well.  Vitamin K Found in green vegetables, gut bacteria in the colon also produces vitamin K. Important for the clotting of blood. Deficiency – poor blood clotting, excessive bleeding.  Vitamin B Found in cereals, yeast extract, liver, brown rice, eggs. There are many different B vitamins, usually occurring together. Perform many different functions. One function is helps the process of aerobic respiration in the mitochondria Deficiency – beri-beri (common in South East Asia), polished rice not brown rice is a staple. People with beriberi have muscular weakness and paralysis Vitamin C – Ascorbic Acid Found in citrus fruits, raw vegetables. Its needed for collagen production. Collagen is a very important protein for tissue repair. Needed for resistance to disease Deficiency – Scurvy – a common occurrence among sailors, with no access to fresh fruit. Uncommon currently. Joint pain Bleeding gums , tooth loss.  Minerals - Iron Minerals aka mineral salts. Only needed in minute amounts. Iron (Fe) is found in liver, red meat, eggs, cocoa, dark green leafy vegetables e.g. dasheen bush/callaloo, spinach, Needed to make haemoglobin, the red pigment in RBCs. Deficiency – Iron deficiency anaemia Not enough red blood cells, less oxygen is delivered to the body’s tissues.  Minerals – Calcium Found in milk and diary, bread, tinned tuna/ salmon, green vegetables. Strengthens bones and teeth Needed for healthy functioning of nerve cells. Needed for proper blood clotting. Deficiency – brittle bones and teeth , poor blood clotting Macronutrients Macronutrients provide us with energy. The amount of energy our body uses at rest, for all our internal organs to function is called the basal metabolic rate. The amount of energy needed depends on the following. Age Gender Physical activity Occupation  People with active jobs will require more energy, than people who are sedentary. Women typically require less energy than men, primarily because women tend to be Macronutrients smaller. Pregnant/ breastfeeding women may require more energy. Energy needs increase from infancy to adulthood. Water 2/3 of the human body is made of water. Water is the main component of the cytoplasm in all our cells. Part of a balanced diet is replacing water lost each day. Lose water as sweat – cools the body Urination  Dietary fibre is mainly cellulose from plant cell walls. Fibre provides bulk, which helps the intestine walls to move food along the canal (peristalsis) Fibre/ Roughage It’s indigestible material. Without it causing peristalsis, constipation can occur. A high fibre diet (regular stools) can help protect against bowel disease, like inflammation and bowel cancer.  Malnutrition If a diet is not balanced an individual can be considered malnourished. Too little energy or too much energy can cause problems. Insufficient vitamins and minerals can cause problems. Malnutrition is not limited to failure to grow. Obesity is malnutrition.  Obesity Most common malnutrition disorder in the Caribbean. If the energy intake is high, due to excess consumption of carbohydrates and fats, there can be weight gain. If weight is 20% above the recommended value for height and weight. An individual is said to be obese.  Body Mass Index Body Mass Index (BMI) – lets us assess if a BMI Category person is underweight, overweight or a normal Less than 18.5 Underweight healthy weight. 18.5 to 24.9 Acceptable BMI looks at a persons height relative to their 25 to 29.9 Overweight 30 to 34.9 Obese (class 1) weight, taller people are expected to be heavier. 35 to 35.9 Obese (class 2) Depending on the value we can group people. Over 40 Severely obese (class 3) Body Mass Index BMI is calculated using this formula No need to memorise  Being overweight or obese comes with serious health risks. Some are Hypertension , high blood pressure. Normal, healthy BP - 120/80 High BP – 140/90 Obesity & Risk Coronary heart disease Factors Diabetes mellitus Arthritis (joint damage) Some cancers e.g. bowel cancer, uterine cancer, prostate Hernias Strokes Varicose veins Obesity- Health Recommendations What do you think about this advice ? Avoid Avoid sugary drinks. Eat Eat starchy foods, fruits, vegetables. Eat Eat low fat foods. Avoid Avoid junk foods, fried foods. Drink Drink adequate water.  Obesity- Health Recommendations Individuals in with hypertension. Reduce salt intake (sodium) Increase intake foods rich in potassium e.g., beans, bananas, leafy vegetables Eat calcium rich foods. Energy Protein Malnutrition Not enough protein and not enough energy. Kwashiorkor and marasmus – are both deficiency diseases, that present similarly. Kwashiorkor is protein deficiency. Marasmus is inefficient amounts of energy providing food.  Energy Protein Malnutrition Kwashiorkor Swelling of body tissues (edema) and swollen liver. Protein in blood helps to absorb water from tissues. Little protein in blood, means water cannot leave tissues, hence swelling. Marasmus Growth retardation Severe weight loss Thin legs and arms To Do List Know all the nutrient deficiencies. Food sources of the nutrients Which foods (examples) contain starch, protein, fats Definition of a balanced diet, malnutrition. Function of vitamins and minerals Gas Exchange The Respiratory System Nathanya Smith Anatomy The trunk contains most of your body’s organs. The trunk is divided into 3 main portions Thorax (chest) Abdomen Pelvis  The Respiratory System Respiratory system, ensures fresh, oxygen-rich air goes into the lungs and stale, carbon dioxide-rich air is removed from lungs. Breathing is the flow in and out of the lungs. Gas exchange is the exchange of oxygen and carbon dioxide, by diffusion at a gas exchange surface. In human, gas exchange surface is in lungs. Lungs Spongy organs within the thorax (chest). They are protected by the ribcage and the backbone.  Apex Lungs Right lung has 3 lobes. Left lung has 2 lobes. Base Breathing Muscles Intercostal muscles Muscles attached to the ribs. External intercostal muscles Internal intercostal muscles Help move the ribs during deep breaths. Below the lungs, there is the diaphragm. A sheet of muscle and fibrous tissue separating the thorax from the abdomen. Most important for inspiration.  Pleura There is a lining encasing the lungs, called the pleura. Between the lining and the lung surface, is the pleural space. In the pleural space, there is pleural fluid. Fluid is a lubricant, preventing the lungs from rubbing against ribs. The Anatomy The respiratory tract consists of Nose/mouth Pharynx Larynx Trachea Bronchi Bronchioles (terminal then respiratory) Alveoli (singular- alveolus) Air Flow Air enters mouth/nose. Air passes through throat to the larynx –site of vocal cords Air enters trachea (neck) then into thorax The trachea branches off into the 2 bronchi.  Air Flow Trachea spilt into 2 bronchi - Each bronchus, enters each lung. The bronchi split into many smaller branches called bronchioles. At the very end of the bronchioles, they are tiny air sacs called alveoli. Respiratory Tract Divided into the: Upper respiratory tract Lower respiratory tract  Respiratory Tract: Passage of Air Air is drawn into the nostrils. Inside is warm and moist (lining of nose produces mucus). Air filtered by hairs that trap particles in the air. Nose & mouth are separated by the palate. Air then passes through the pharynx to the larynx (voice box) then to the trachea (windpipe). At the top of the trachea, a piece of cartilage (epiglottis) closes the trachea while swallowing. – Prevents food/liquid from entering windpipe. The Pharynx Respiratory Tract Air flows from the larynx to the trachea. Trachea has C-shaped rings of cartilage. Cartilage holds the tube open. The trachea goes through the neck, and into the thorax. Respiratory Tract The trachea branches into 2, tubes called bronchi. Each bronchi then branches into smaller, thinner tubes called bronchioles. Bronchioles end in the alveoli. Respiratory Epithelia Walls of the upper respiratory tract (trachea to terminal bronchioles) are lined with ciliated epithelial cells and goblet cells. Goblet cells produce mucus, which traps particles like dust, pollen and bacteria. Cilia then sweeps trapped particles and mucus to the back of the buccal cavity where it can be swallowed – mucociliary escalator  Alveoli Grape like sacs at the end of bronchioles. Alveoli walls are thin, one cell thick. Around the alveoli, they are many blood capillaries. Capillaries are the tiniest blood vessels. They connect arteries to veins. The structure of capillaries make them make them perfect for gas exchange.  The movement of molecules from area What is of high concentration diffusion? to low concentration until evenly distributed. Alveoli Thin alveoli walls are gas exchange surfaces. The tiny thin walled capillaries, allow oxygen to diffuse from the lungs and into the blood. Carbon dioxide diffuses from blood into the lungs. Breathing brings constant supply of O2 and the removes CO2 produced from cellular respiration.  Features of Alveoli Thin walls, one cell thick. Simple squamous epithelium Easy for CO2 and O2 to diffuse through. Moist, some alveoli cells secrete watery liquid, prevents them from drying out. Large surface area, arrangement into many bunches of sacs. Many capillaries, good transport system; brings deoxygenated blood to lungs, and takes oxygenated blood to the body.  Why do we need O2, Where is the CO2 coming from? Oxygen is needed for aerobic respiration, within all the cells in the body. Remember, cells constantly need energy, and therefore constantly need O2 supply, and CO2 constantly needs to be removed. The carbon dioxide is a waste product of cellular respiration. Physics Let’s Talk Pressure Pressure is the force a substance exerts on a surface. 𝒇𝒐𝒓𝒄𝒆 Pressure = 𝒂𝒓𝒆𝒂 Gas particles will exert a force on its container. In this case the container = lungs. Breathing In – Inspiration Breathing occurs so that air in the alveoli is refreshed. Movement of air – air will move from area of high pressure to low pressure. When we inhale our chest expands. The pressure inside our lungs becomes less than atmospheric pressure.  Breathing In – Inspiration The diaphragm contracts, it moves downwards. The external intercostal muscle contract and the internal intercostal muscles relax. Together this moves ribs and sternum upwards and outwards. This increases the volume of the chest cavity, therefore gas particles exert less force on lungs (pressure decreases) Air can move into the lungs from high pressure outside to low pressure inside the lungs.  Breathing out – Expiration Passive process – normally relies on the relaxation of inspiratory muscles. The diaphragm relaxes, pressure exerted by the abdomen pushes upwards. The internal intercostal muscles contract and external intercostal muscles relax to move the ribs downwards and inwards. Volume in the chest decreases, pressure increases. Higher pressure in lungs, means that air flows outside the lungs where pressure is lower.  Rib cage – up and out Rib cage – down and inwards Diaphragm moves down (contracts) Diaphragm moves up (relaxes) Volume of thorax increases Volume of thorax decreases Volume of lungs increases Volume of lungs decreases Air pressure in the lungs decreases Air pressure in the lungs increases Air flows into the lungs ‘ Air flows out of the lungs ‘ Breathing IN Breathing OUT  Gas Exchange Cellular respiration occurs in most living organisms Therefore gaseous exchange has to take place in organisms regardless of size. Amoeba, unicellular organism. Their body surface is the gas exchange surface. Gases crosses the cell membrane by diffusion. One cell, so small that surface area to volume ratio is large enough for enough O2 to enter and CO2 to leave. Gas Exchange Larger organisms need more oxygen. Oxygen has to diffuse across a surface entire organism and distributed all over. Dual effort between lungs and circulatory system to supply O2 and remove CO2  Gas Exchange Earthworms are multicellular organisms. Like amoeba, they use their body surface for gas exchange. However, earthworms are much larger than a single celled amoeba. O2 cannot diffuse to the centre of earthworms, without help. This why transport systems are needed. Blood helps transport gases, inside of blood vessels (capillaries) Gas Exchange In plants, gas exchange in the leaf. The leaf surface has special openings called stomata. Stomata allows CO2 to diffuse into the leaf and O2 to diffuse out. Leaves are thin, and have a large surface area. Gas Gas exchange surfaces have special properties. Exchange 1. They should have a large surface area, plenty space for gases to diffuse and facilitate needs. Surfaces 2. 3. A moist surface so gases can dissolve before diffusion. Thin walls, so it’s easy for gas to diffuse across. 4. Good supply of O2, brought to by breathing movements. 5. Very good blood supply to maintain concentration gradients of oxygen and carbon dioxide. Control of Breathing Rhythmic breathing controlled respiratory center in medulla in the brain. Special receptors in the body can detect changes needed to maintain homeostasis. Changes include pH and CO2 concentration in the blood and physical activity. Rate of breathing can then be regulated by sending impulses to intercostal muscles and diaphragm. Exercise and Respiration Rate Exercise – rate of cellular respiration increases CO2 concentration increases in blood Chemical receptors in blood vessels detect increase Impulses sent to breathing center in the medulla Breathing center sends impulses to the intercostal muscles and diaphragm Rate and depth of breathing increases Concentration of CO2 returns to normal  Respiratory Tract Disorders COPD – chronic obstructive pulmonary disease. Group of lung diseases associated with decreased airflow in the lungs. Includes chronic bronchitis and emphysema (usually due to cigarette smoking) Chronic bronchitis Inflammation of the airways, excessive mucus is produced that clogs the airways. Overproduction and hypersecretion of mucus by goblet cells. Results in cough and difficulty breathing. Blue bloaters. Respiratory Tract Disorders Emphysema – over inflation of the lungs Air is trapped in the terminal bronchioles and alveolar sacs. Alveolar walls are destroyed (elastin destroyed by elastases) gas exchange can’t occur effectively. Less surface area of gas exchange to occur. Less O2 absorbed into the bloodstream. Patients will have barrel chest. Pink puffers. Respiratory Tract Disorders Asthma Episodic; maybe triggered by allergens or exercise, upper respiratory tract infections, stress. Inflammation of the bronchi, swelling and constriction of smooth muscles in the airways. Difficulty breathing, cough, wheezing. Other Respiratory Tract Disorders Lung cancer Leading cause of death in the US in both men and women Respiratory tract infections Range from common cold to life threatening illnesses. Pneumonia Inflammation of the alveolar spaces. May be bacterial or viral Question 1 Which of the following are not gas exchange surfaces. A. Human skin B. Cell membrane of amoeba C. Cockroach exoskeleton D. Fish lamellae E. Air sacs at the end of bronchioles. Question 2 Order the direction of airflow in the respiratory tract. Trachea Alveoli Larynx Bronchi Nostrils Bronchioles Pharynx /Mouth To Do List State the features common to gas exchange surfaces. List gas exchange surfaces of Amoeba, earthworms, humans, flowering plants. Define breathing Describe mechanism of breathing in humans (inspiration and expiration) Describe role of ribcage, intercostal muscles. The Heart Nathanya Smith  Unicellular organisms like Surface Area amoeba have a large surface area to volume ratio. The surface of the cell is big enough to facilitate gas exchange for the entire cell. Some multicellular organisms, flatworms and tapeworms have thin bodies – thin enough that diffusion is sufficient for gas exchange. Surface Area A small surface area to volume ratio, diffusion of gas is not sufficient. O2, nutrients, water can’t be delivered to tissues deep in the body. Therefore a transport system is required. Transport in Humans Transport system is humans, has 3 main characteristics. The blood – circulatory fluid The heart – Contractile pumping device Blood vessels – tubes which the fluid can circulate  Transport in Humans There are 2 types of transport systems in animals Open Blood system Blood is pumped into open spaces Veins are open ended. Found in molluscs and arthropods. Closed Blood flows within blood vessels. Blood pumped by the heart all around the body, then back to the heart. Blood to tissues will change dependant on when it is needed. Only exit and entry is through the walls of the vessels.  Transport in Humans Circulatory system is closed, and it is also a double circulatory system. Pulmonary circulation – Right side of heart Systemic Circulation – Left side of heart Transport in Humans In the pulmonary circuit, deoxygenated blood returns to the lung from the body. Blood returning to lungs is CO2 rich and O2 poor. In the systemic circuit, oxygenated blood leaves the lungs to be delivered to tissues to be used for aerobic respiration. Cerebral Coronary Renal Splanchnic Skeletal muscle Skin Pump Heart is located in the thorax, between the lungs. It is protected by the sternum. The heart is mainly muscle – cardiac muscle The heart is a double pump Right side pumps blood to the lungs Left side pumps blood to the entire body.  RECALL What are the identifying features of cardiac muscle? Heart Structure Cells → Tissues →Organs Heart cells – cardiomyocytes Tissue – cardiac muscle Heart Structure The heart is divided into 2 sides (left and right) by the septum. Septum prevents the mixing of deoxygenated and oxygenated blood. Each side, divided into 2 chambers – atrium and ventricle 4 chambers, right and left atria, right and left ventricles.  Heart Wall Pericardium Outer most 2-layered sac covering the heart. Between the 2 layers, there is the pericardial space where pericardial fluid is secreted to lubricate the pumping heart. Outer layer is fibrous and strong preventing the heart from overfilling. The inner pericardial sac is attached to the heart – epicardium Myocardium Muscle layer of the heart – cardiac muscle Held in place by strands of elastin and collagen The heart muscle also requires nutrients and O2 and are supplied by the coronary arteries. Endocardium Inner most layer of the heart covering all the chambers.  Heart Walls Walls of the atria are thinner and less muscular than the walls of the ventricles. Atria pump blood to the nearby ventricles. Walls of the left side of the heart are more muscular, thicker than the right side of the heart. Right side pumps blood to the nearby lungs, lower pressure protects delicate lung capillaries. Left side needs to pump blood to all the organs of the body at very high pressures.  Valves Between each atrium and ventricle there is the atrioventricular valves. Right atrium is separated from the right ventricle by the tricuspid valve. Left atrium is separated from the left ventricle by the bicuspid(mitral) valve. At the base of exiting vessels of the heart, there are semilunar valves. Aortic valve at the base of the aorta Pulmonic valve at the base of the pulmonary artery. Simplified drawing Blood flow through the Heart 1. Blood flows from lungs to the left atrium via pulmonary vein. 2. From left atrium to left ventricle, through the bicuspid/mitral valve. 3. From the left ventricle to the aorta the aortic valve. 4. From the aorta to the arteries of the body (heart, kidneys, brain skeletal muscle, skin etc) 5. From tissues to systemic veins and vena cava. 6. From vena cava to the right atrium. 7. Right atrium to the right ventricle through the tricuspid valve. 8. From the right ventricle to the pulmonary artery. 9. Pulmonary artery to the lungs to for oxygenation. Blood flow through the Heart 1. Blood flows from lungs to the left atrium via pulmonary vein. 2. From left atrium to left ventricle, through the bicuspid/mitral valve. 3. From the left ventricle to the aorta the aortic valve. 4. From the aorta to the arteries of the body (heart, kidneys, brain skeletal muscle, skin etc) 5. From tissues to systemic veins and vena cava. 6. From vena cava to the right atrium. 7. Right atrium to the right ventricle through the tricuspid valve. 8. From the right ventricle to the pulmonary artery. 9. Pulmonary artery to the lungs to for oxygenation. Blood Vessels The walls of blood vessels are made of 3 different tissue types. Endothelium - Squamous lining, forms a smooth lining. Endothelium is the epithelial tissue lining the blood vessels and the heart. Muscle tissue Fibrous tissue elastic tissue and collagen fibres. Arteries Deliver oxygenated blood to the body’s tissues. Thick walled, with elastic tissue in walls to with stand high pressures of the heart. Elastic tissue allows it to stress and recoil, to maintain blood pressure. Arterioles These are the smallest branches of the arteries. Walls are muscular. Narrower than arteries.  Vessel walls are thin, only one cell thick. Capillaries Thin walls makes it easy for gas to diffuse, water, solutes ( glucose, amino acids) Vessels between arteries and veins. Larger surface area for exchange of substances. Capillaries Blood flow is fastest in the larger vessels. As vessels get smaller, blood flow slows allowing diffusion to the tissues and from the tissues. Capillaries form networks (capillary beds) between cells and tissues – no cell is far away from blood supply. Fluids can be exchanged between the capillaries, cells and the fluid around the cells (extracellular fluid) Venules Venules are the smallest veins. Venules drain capillaries of the deoxygenated blood and join to the small veins. Small veins then drain into the larger veins.  Veins Veins progressively merge to form larger veins. Largest vein, vena cava returns blood to the heart. Walls are thin, muscle layer much thinner than arteries. Blood is flowing at lower pressures. Veins have semilunar valves to prevent the backflow of blood. Pacemaker Cells Pacemaker cells make the conduction system of the heart. Specialised cells in the right atrium called the pacemaker cells – sinoatrial node. The SAN regulates the hearts contractions. Pacemaker cells send out the electrical impulses to the atria and ventricles signalling them to contract.  Pacemaker Cells The AV node is found in the intra-atrial septum – receives impulse from the SAN. Bundle of His (AV bundle) runs along the ventricular septum, receives impulse from the AV node. Splits in to right and left branches and then travels to the Purkinje fibers in the ventricular walls. SA AV Bundle Purkinje node node of His fibres Cardiac Cycle Signals from the SAN triggers the initiation of the cardiac cycle. Rhythmic contractions called systole and relaxation of the heart called diastole. The contraction of the heart forces blood from atria to ventricles and from ventricles to the exiting vessels of the heart.  Systole Muscle contraction forces blood out of the heart’s chambers. Makes the chambers smaller and squeezes the blood out. When heart muscles contract this is systole. Atria muscles contract and force blood into the ventricles. Pressure from atrial contractions force the atrioventricular valves open. Ventricles fill with blood. Pressure in the ventricles close the AV valves close, blood won’t backflow into the atrium. The pressure in the full ventricles is now high, forcing the semilunar valves open. Diastole Heart muscles relax. The chambers increase in size, allowing blood to flow into them. Deoxygenated blood returns to the right atrium through the vena cava. Oxygenated blood returns to left atrium through the pulmonary vein. Blood Pressure Blood pressure is measured at the brachial artery in the antecubital fossa. The systolic pressure occurs when contracting ventricles force blood into arteries. Diastolic pressure, the lowest pressure, occurs when ventricles are most relaxed. BP is measured in millimetres of mercury (mmHg). It is recorded as SBP over DBP. Normal pressure 120/80 mmHg Diseases of Heart & Vessels Hypertension Consistently high BP. More likely to be high in persons who smoke, overweight, drink excessive alcohol, sedentary individuals or regularly eat high fat/high salt diet. Hypertension stimulates the development of atheromas and increases the chance of developing angina or suffering from a stroke or heart attack. Cardiovascular disease  Cardiovascular disease Includes diseases that of the coronary arteries that supply the heart carotid artery which supplies the brain and peripheral arteries which supply the body. Cardiovascular disease is a leading cause of death worldwide. Risk factors: Hypertension, Smoking, Diabetes, Obesity, hyperlipidemia, physical inactivity, age> 50, men > women, family history, ethnicity, alcohol *Compliments Dr. Chabrol Atherosclerosis Hardening of the arteries. Lipids build up in the lumen, causing it to narrow. Fibrous connective tissue form over the lipid forming an atherosclerotic plaque. The plaque can rupture the artery wall causing a clot to form. Plaques can rupture & become lodged downstream in smaller arteries. This can result in a few different cardiovascular diseases. Blocked arteries → stroke or heart attack.  Myocardial infarction Myocardial = heart muscle. Infarction = suffocation due to lack of O2. Commonly known as heart attack. Occurs when blood flow is interrupted to a part of the heart damage to the heart muscle death to myocardial cells. MI occurs due to blockage to a coronary artery often due to a blood clot or ruptured plaque. MI causes crushing, substernal chest pain radiating to neck, jaw & arms. Sometimes it may occur without symptoms. May cause sudden death, or permanent heart damage if the patient survives. *Compliments Dr. Chabrol Angina Partial blockage of a cardiac artery. A muscle exercised without adequate blood supply will cause pain, in the heart = angina. Even light exercise e.g. climbing stairs can cause pain similar to a heart attack. How do we combat CVD? Question Label the structure of the heart in the diagram. To Do List List components of transport system. Describe heart structure, valves, chambers, associated vessels. Explain how heart functions to move blood to the lungs. Explain purpose of valves. Blood components and their functions. Structure of RBCs relate to their function. Understand CVD. Blood Nathanya Smith  Internal Transport System  Circulatory fluid. Flows through vessels, arteries, veins, capillaries. Blood Substances are transported to tissues and exchanged with the surrounded tissues. E.g. exchange of CO2 and O2 in the alveoli. Tissues are made of cells, and within the cells – cellular respiration. Blood Blood is a liquid connective tissue. Remember – tissues are group of similar cells which work together to carry out a particular function. Blood is a mixture – solid cells, fragment of cells, in plasma.  Blood ` Blood Cells Plasma (55%) (45%) Red Blood Dissolved Water (90%) Cells substances (majority) Amino acids, White Blood proteins, salts Cells Platelets  Plasma Liquid part of blood. Plasma is up to 90% water. Water with chemicals dissolved in it: Nutrients Glucose ,Amino acids Lipids, Vitamins Mineral ions (Na+, Ca2+, Cl-) Waste Urea, CO2 Blood proteins Albumin, Antibodies, prothrombin Hormones Insulin, glucagon, adrenaline/ Red Blood Cells – Erythrocytes Have special shape called a biconcave disc. Its shape allows it to change shapes and pass through capillaries. No nucleus, no mitochondria. Cytoplasm full of haemoglobin. Hemoglobin is a red iron containing pigment that gives red blood cells its colour. More space to hold haemoglobin to transport O2 and CO2 Type of protein structure? Hb Structure 4 polypeptide chains – tetramer. 2 identical β (beta) chains 2 identical (alpha) chains. Red Blood Cells Majority of the cells in the blood. Biconcave disc. Biconcave shape increases the surface area. Large surface area for gas exchange. Allows them to squeeze through membrane capillaries. Made in the bone marrow. 1 drop of blood contains ~ 5 million cells.  Red Blood Cells Transport Oxygen Haemoglobin helps the RBC to carry oxygen. In the lungs where O2 concentration is highest, Hb will combine with oxygen to form oxyhemoglobin. One single molecule of Hb can carry 8 O2 molecules One RBCs can carry approx. 250 million Hb molecules.  Red Blood Cells Transport Oxygen In the tissues, oxygen concentration is lower. The oxygenated erythrocytes will carry oxygen to the tissues. The oxygen will be offloaded on the tissues. The Hb will pick up CO2. Hb will now become carboxyhaemoglobin, which will head back to the lungs for gas exchange.  Carbon Dioxide Transport CO2 is transported 1. About 5% - Attached to proteins – carboxyHb. 2. About 5% - Some is transported as dissolved in blood plasma. 3. 90% carried in plasma as bicarbonate (bicarbonate buffer system) The formation of bicarbonate from CO2 requires the enzyme carbonic anhydrase (CA) CA is found in our RBCs, not in the plasma. Little conversion to bicarbonate occurs in the plasma.  Bicarbonate Buffer System In the tissues CO2 diffuses into RBCs CA quickly converts the CO2 to carbonic acid (H2CO3). H2CO3 is unstable intermediate and quickly dissociates to H+ ions and bicarbonate ions. Conversion of CO2 to HCO3- is fast, drives uptake of CO2, down concentration gradient. The HCO3- is exchanged with Cl- ions – chloride shift. HCO3- exits into the plasma Cl- enters the RBC.  Bicarbonate Buffer System In the lungs Chloride shift HCO3- bicarbonate enters the RBCs Cl- leaves and reenters plasma. Bicarbonate and H+ ions forms carbonic acid. Carbonic acid is converted back into CO2 and H2O with the help of carbonic anhydrase. CO2 diffuses across the membranes and can leave the body through exhalation  Blood Cells originate from Bone Marrow Recall - what are stem cells? What is hematopoiesis?  White Blood Cells Bone Marrow Aka Leucocytes. Red Blood White Blood The cells are also made in Cells Cells Platelets the bone marrow. They are different types of WBCs. Lymphocytes Phagocytes Lymphocytes Phagocytes  White Blood Cells They make up a small portion of whole blood. Very important in the immune response. These will protect the body from invading pathogens, dying/ damaged cells, cancer cells.  White Blood Cells- Phagocytes Phagocytes Phagein – to eat These are cellular “eaters”. The engulf cells, pathogens and debris. The process by which they “eat” is called phagocytosis. Large cells. These have lobed nuclei. Lobed nucleus help cells leave blood through small gaps in the capillary walls. Cytoplasm has many small vacuoles with digestive enzymes.  Phagocytosis The cells will invaginate, taking the organism into its cytoplasm. The result is a sac made with the cells own cell membrane, with the invading particle inside. The sac, or vesicle will fuse with a lysosome. Remember a lysosome is an organelle with digestive enzymes. Fusing with the lysosome the enzymes will dissolve the particle, destroying it. There are 2 types of phagocytes. Monocytes Neutrophils White Blood Cells - Lymphocytes Lymphocyte Small cell with little cytoplasm, few mitochondria. Nucleus is large occupying most of cytoplasm. If an individual has an infection they activate to produce antibodies. Antibodies are proteins. Lymphocytes vs Phagocytes Can you note the differences?  Stem cells are special type of cells Platelets that differentiate into different types of cells Tiny cell fragments with no nucleus. Made in bone marrow. Important for the clotting of blood. Prevents excessive blood loss from damaged blood vessels. Prevents pathogen entry from broken skin. Scab temporarily plugs wound, until stem cells in the skin can divide by mitosis, repairing the damaged skin. Damaged Blood Vessel  Hemostasis Blood vessels will contract – to reduce blood flow at site of damage. Recall – smooth muscle layer in blood vessels. Involuntary response to blood loss. Aka vasospasm, vascular spasm.  How Blood Clots Calcium ions Platelets release substances that will react with Ca2+ ions to activate the enzyme prothrombin. Prothrombin is an inactive enzyme found in blood activated plasma. Once activated prothrombin becomes thrombin. Once thrombin is an active enzyme that activates another reaction. Thrombin will catalyse the conversion of fibrinogen(soluble) to fibrin(insoluble) Fibrin forms a meshwork that will trap platelets and other cells, which dry to form a scab. To Do List Structure of blood. Why is the shape for RBCs important? Where is blood made? Function of the cells. Role of blood in the immune response. Define antibody. Role of platelets and clotting. What is happening at a molecular level when RBCs reach tissues. Can you differentiate between a WBC and RBC? Differences in structure and function. Urinary System Nathanya Smith Excretion Excretion is the removal of waste products of metabolism from the body. If allowed to accumulate – disrupts homeostasis. Not be confused with egestion (defaecation) – removal of undigested food from the gut. Osmoregulation Body Fluids Cell Extracellular Maintenance of constant Contents Fluids osmotic conditions in the body. It involves regulation of Blood Water content plasma Some solutes of body fluids Na+ Tissue fluids K+ Cl- Lymph  Nitrogenous Compounds – from the breakdown of proteins, nucleic acids or excess amino acids. Urea NH3 Uric acid Excretory Products CO2 from the cellular respiration. Bile pigments from the breakdown of heme in the liver. Excretory Structures Skin Water, urea and salts actively secreted from capillaries in the skin by the tubules of the sweat glands. Helps regulate body temperature. Lungs CO2 and water vapour diffuse from moist surfaces of the lungs. Liver Bile pigments pass through the duodenum in bile for removal in the feces. Kidney Major organ for excretion and osmoregulation. Primary functions. Removal of waste products. Regulation of water content of body fluids. pH regulation. Regulation of the chemical composition of body fluids, which maybe in excess.  Kidney is located retroperitoneally – back Location lower part of the abdominal cavity. Left kidney slightly higher than right (due to liver)  Blood Supply Receives blood from the aorta via the renal arteries. Renal arteries branch to into arterioles. Arterioles entering the glomerulus of a renal corpuscle are called afferent arterioles. Filtered blood leaves the glomerulus via an efferent arteriole. Blood then flows around the proximal tubules and distal tubules and loop of Henle in the medulla. The vasa recta run parallel to the loop of Henle. Renal veins return blood to the heart via the inferior vena cava. Structure Urine forms in the kidneys. Then passes thru the ureters to the bladder. Urine stored in the bladder until released via urethra. Two sphincter muscles. One under voluntary control Controls release of urine (urination, micturition)  Structure Transverse section of the kidney. Cortex + medulla = functional part of the kidney. Outer cortex Covered by fibrous connective tissue - capsule Glomeruli (visible to naked eye) Inner medulla Renal pyramids Tubular part of the nephron Blood vessels Apex of each pyramid is called papilla. Pyramids project into the pelvis which leads to the ureter. Nephron Basic functional unit of the kidney and its blood supply. Each kidney has approx. 1 million nephrons. Total length of tubules offer large surface area for exchange of materials. 2 types Cortical nephrons Juxtamedullary nephrons Nephron Cortical nephrons Found in the cortex Relatively short LOH Juxtamedullary nephrons Renal corpuscle is close to the junction of cortex and medulla Long LOH Nephron Renal corpuscle Glomerulus – ball/knot of capillaries. Bowman’s Capsule Proximal convoluted tubule Descending loop of Henle (LOH) Ascending LOH Distal convoluted tubule Collecting duct Urine Formation Ultrafiltration Selective Reabsorption Secretion Excretion Ultrafiltration First step in urine formation is the ultrafiltration of blood. Ultrafiltration is filtration under pressure. This takes place in the Bowmans capsule. The structure is adapted for filtration. Filtration takes place through 3 layers. 1. Endothelium of blood capillary 2. Basement membrane of blood capillary 3. Epithelium of renal corpuscle.  Blood Capillary endothelium Very thin Filtration Perforated (fenestrated) – has many tiny pores ~ 70-100 nm in diameter Plasma proteins can pass through and fluid, but not blood cells. Membranes Blood capillary Basement membrane Epithelial cells rest on BM. Meshwork of collagen fibres Plasma proteins cannot pass through. Filtration Membranes Epithelium Highly modified for filtration. Have specialised cells are called podocytes. Wrap around capillaries Attached to basement membrane by foot processes. These cells interlink with each other, leaving minute spaces between them called slit pores or filtration slits. Water, small solutes can pass through – final filtration barrier. Ultrafiltration Blood is coming from aorta to renal arteries to glomerulus at high pressures. Glomerulus – knot of capillaries in the renal capsule. As blood travels through the arteriole to the capillaries, at increasing pressures due to the narrowing of the vessel walls. Ultrafiltration High pressures squeeze water, small solute molecules out of the capillaries through the epithelium of the renal capsule to the interior of the capsule. Large molecules(RBCs, platelets, proteins) are left behind in the blood. So as blood flows from afferent arteriole to efferent arteriole, through the glomerulus, it loses water.  Ultrafiltration The filtered blood is called glomerular filtrate. About 1.5L of urine is produced daily. The kidney can filter blood at a rate of about 180L/day (120mL/min)= glomerular filtration rate (GFR) GFR – rate at which fluid is filtered into Bowmans capsule. Difference between urine produced and fluid filtered suggests reabsorption of water back into the blood. Consider this! - If blood flowed straight out of the kidneys without reabsorption imagine how much fluid you would lose! Why REabsorption? 1st absorbed in digestive tract. Reabsorption & Secretion Reabsorption is the process in which solutes and water are removed from filtrate and transported back to the blood. During ultrafiltration, useful substances can be lost along with the waste products. The nephron will selectively reabsorb useful substances that were filtered out of the blood. Nephron can also secrete unwanted substances from blood to filtrate. Secretion Transfer of materials from the peritubular capillaries to lumen of renal tubules. Primarily by active transport. Secretion of drugs from peritubular Many drugs are eliminated by secretion. Proximal Convoluted Tubule Longest, widest part of nephron – carries filtrate from Bowman's capsule to LOH. Carries filtrate from the Bowmans capsule to the LOH. Most (80%) of the glomerular filtrate is reabsorbed here. Glucose, amino acids, vitamins, hormones, most of NaCl, water. By Na+ transporters and sodium potassium ATPase pumps. 50% urea reabsorbed, passively. Proximal Convoluted Tubule Walls of the nephron are made of a single layer of cubed- shaped cells – cuboidal epithelial cells. Cells in PCT adapted for reabsorption. Large surface area – microvilli and basal channels. Microvilli forms brush border. Numerous mitochondria. For active transport. Blood capillaries close by. Loop of Henle Hairpin like tube - serves to conserve water. Longer the LOH – more concentrated urine can be. Distinct regions Descending limb has thin walls. Thin ascending limb. Thick ascending limb. Countercurrent Multiplier Loop of Henle Descending limb is highly permeable to water and most solutes – easy diffusion through the walls. Ascending limb (thick and thin) – completely impermeable to water. The cells in the thick ascending limb can reabsorb(tube to blood capillaries) ions – Na+, Cl-, K+ Because water cannot follow the ions through the impermeable wall, the fluid in the thick ascending loop can become dilute. Fluid flowing down the descending limb, becomes more concentrated as water flows out of the tubule.  Countercurrent multiplier – LOH Countercurrent multiplication system serves to concentrate urine (tubular fluid) in the medulla. Vasa recta – special peritubular capillaries running along the LOH. The hairpin turn helps to slow blood flow to allow exchange. Osmotic gradient is created here. Difference in solute(ions) concentration between regions.  Main takeaway – Countercurrent system makes the medulla salty. Provides a gradient for concentration in DCT and CD in the presence of ADH. In other words it is important for concentration of urine, 2. Osmosis – is movement of water molecules from area 1. Actively pumping out Na ions of high concentration to low makes the surrounding medulla concentration through semi “salty”. permeable membrane 3. Descending limb = So as fluid continuously flows area of high conc. of through the tubule – becomes water. more concentrated then more Medulla area of low dilute. conc. Distal Convoluted Tubule Similar structure to proximal convoluted tubule – microvilli for reabsorption Numerous mitochondria. Largely responsibly for reabsorbing water. Collecting Ducts Water is reabsorbed here. These channel urine into the papilla, empty into renal pelvis, to the ureters Volume of water reabsorbed depends on the water in the blood. Well hydrated, large volume of water in blood(dilute) Less water will be reabsorbed. Resulting in dilute urine. Dehydrated, e.g. after a sweaty workout, salty meal. More water will be reabsorbed to conserve water. Results in more concentrated urine. ADH The control of how much water is reabsorbed is controlled by the hormone antidiuretic hormone (ADH) aka vasopressin. ADH is made in the brain (hypothalamus) and secreted by the posterior pituitary gland. Osmoreceptors – are special receptors in that signal that there are changes in blood concentration – too dilute or too concentrated.  ADH Increases the permeability of the collecting duct to water. It signals to the membrane cells of tubules to make more water channels (aquaporins) Water channels are protein channels that allow polar water molecules to pass through the lipid bilayer. Disorders of the Kidney Diabetes Insipidus Not to be confused with diabetes mellitus. If the body can no longer secrete ADH. The body does not make aquaporins to reabsorb water. The body will produce large amounts of dilute urine. People with DI are at risk of dehydration.  Kidney failure will result in death if not treated. Kidneys may perform poorly due to Kidney Disease Ageing – kidney function decreases with age Chronic kidney disease – damage over time Acute kidney disease – relatively short progression. Dialysis Patients with kidney require hemodialysis, for several hours, a few times a week. Dialysis machine will pump blood gently out of the artery and blood circulates through the dialysis tubing. A small dose of the drug heparin (anticoagulant) will be administered to prevent the blood from clotting in the tubing.. Dialysis tubing is semi-permeable similar to the cell membranes of the nephron tubules.  Dialysis Dialysis tubing is bathed in the dialysing solution. Due to osmosis solute concentration will be corrected similar to correction in nephrons. Dialysing solution has Correct temperature Correct ion balance (Na+, K+ Cl-, Mg2+ , Ca2+, HCO3-) Correct pH, nutrients e.g. glucose etc. Urine and Diagnosis Because the kidneys are excretory organs. By-products of many chemical/metabolic reactions are excreted in urine. Urine analysis is used to assess, monitor the progression and diagnosis many different diseases or body states. Color, odor  Common Urine Tests hCG hCG – beta human chorionic gonadotropin Hormone secreted by placenta during pregnancy hCG in urine = positive test = pregnant Bacteria/ yeasts in urine Urinary tract infection (UTI) Bacteria colonizing the urethra or any point along the tract Common Urine Tests Proteins Blood Glucose Drugs in Urine Drugs metabolites Methamphetamines Heroine Cocaine Marijuana Protein & Glucose in Urine Presence of proteins in urine suggests that large molecules are passing through the ultrafiltration membranes of the Bowmans capsule. Individuals with diabetes mellitus are unable to control the blood glucose concentration. Glucose in blood suggests a person may have diabetes mellitus. So much glucose passes through the nephron, that even with reabsorption in the PCT there is glucose left in the urine. Question 1 Question 1  Glomerular filtrate is closest to which of the following? Question A. Whole blood 2 B. Urine C. Blood Plasma  Glomerular filtrate is closest to which of the following? Question A. Whole blood 2 B. Urine C. Blood Plasma Links Self Quiz Simple Anatomy Video To do list Anatomy of kidney What artery supplies the kidney with oxygenated blood? Can you draw and label the nephron? Can you briefly describe what is happening at each part of the nephron? What is the role of the kidney? What’s the role of ADH? How does ADH work? Why is it reabsorption in the kidney?