Skeletal Muscle Anatomy PDF

SKELETAL MUSCLE ANATOMY: SrtceTIOR Amuaie corents of hurcred: te ihowseh ut...

SKELETAL MUSCLE ANATOMY: SrtceTIOR Amuaie corents of hurcred: te ihowseh ut rahe Cot, Pin COMNertive tniwe vel ABoNg bho vewet, ard nerve finer Peace Fenciahe (4 portion of the munca) A taveicte © 6 dexrete beretio of emacte cot, at of taeccte segregated fram We rest of the manic by « COMNOCTIER Tense WER A meats finer = an elongates mumtrecdeme cot (Chat ¢ Darcied (trated) aapearsere Pat enn Boe Wyttes Myotitet oF Riel jromptes crgaewils compcned ut Senden of = Myetinns are redibe cont actite etaments tht ryptdarnenty Occupy moet OF the mutts cel vohene. Competed Of ar Orrer es ae anyed eral Vo end, UNey ager fancied and banch of advent mmyof awit ae apes. © wet tar are of two type — eck and thin heck Mamnent conta buretieg rrpenen mrctecisen thir Nlererin Comten actrry motersées (pun other grater The sinterg of the then Marrerm pert the tuck filaments prodaces rregcle shortening Elastic Mamenta(not own here} nantes the crpernsation of the A tart ord growete ehatn recod eaten recto enetracton ence SLIDING FILAMENT THEORY: The thick filaments (myosin) and thin filaments (actin) are both proteins involved. ¢ Needs Calcium and ATP in order to form cross-bridge. ¢ Myosin forms a cross-bridge to actin, and myosin grabs and pulls actin towards it. ¢ Filaments slide over each other and overlap, causing muscle to shorten. ¢ Myosin continues to let go and grab onto the next part of actin. ¢ As the thick and thin filaments interact, sarcomeres shorten and pull ends of muscle fibre together. t MUSCLE GROWTH/REGENERATION: ¢ Hypertrophy: Increased tissue size due to increase in the size of cells. ¢ Hyperplasia: \ncreased tissue size due to increase in cell number. ¢ Atrophy: Decreased tissue size due to decrease in size of cells. NEUROMUSCULAR JUNCTION: ¢ Action potential travels down motor nerve and synapses with muscle fibre (neuromuscular junction). * In order for muscle contraction to occur, neurotransmitters are required (Aceytlcholine) ¢ Inorder for muscle relaxation, Aceytlcholine Esterase is required to break down ACh. MUSCLES IN THE HUMAN BODY: 42 MUSCULAR SYSTEM DEFINITIONS: ATP: lt is the high-energy molecule that stores the energy our bodies need. ¢ ADP: When ATP releases energy, it results in ADP (due to one less phosphate molecule) ¢ Muscle Fibre: |s the type of cell found in muscle tissue. ¢ Myoblast: Differentiates to give rise to muscle cells. When these fuse together, muscle fibres are made. Myofibril: Any of the elongated contractile threads found in striated muscle cells. ¢ Thin Filament (Actin):A protein which forms the contractile filaments of muscle cells with myosin. ¢ Thick Filament (Myosin): A protein which forms the contractile filaments of muscle cells with actin. ¢ Myosin Head: These extend from myosin filaments and attach to actin. ¢ Elastic Filament (Titin): Acts as a molecular spring which is responsible for elasticity in muscles. ¢ Sarcomere: \s the basic/structural unit of muscles which is shortened during contraction. ¢ Cross Bridge: The molecular structure consisting of a myosin head group bound to an actin molecule. ¢ Muscle Tone: Certain degree of contraction or undertone of contraction when muscles are at rest. Muscle tone allows us to maintain posture, stabilise joints and has a ready response state. ¢ Flexion: Decrease in the angle between two bones. ¢ Extension: Increase in the angle between two bones. Agonist: The muscle that is being contracted ¢ Antagonist: The muscle that is in a relaxed state to support contracting muscle. Origin: Attachment of muscle to stationary bone ¢ Insertion: Attachment of muscle to moving bone. ¢ Abduction: Movement away from the body ¢ Adduction: Movement towards the body ¢ Circumduction: Movement in a circular motion (arm/hand) 43 ENZYMES: ¢ Large protein molecules ¢ Speed up the rate of a chemical reaction in living organisms. « Name normally ends in ‘ase’ ¢ Individual 3D shape ¢ Lock & Key (needs a specific substrate) DIGESTIVE SYSYEM: The function of the digestive system is digestion and absorption. Digestion is the breakdown of food into small molecules, which are then absorbed into the body. The digestive system is divided into two major parts, these are: * Digestive Tract (Alimentary Canal): - Is a continuous tube with two openings, the mouth and the anus. - Consists of mouth, pharynx, oesophagus, stomach, small intestine, and large intestine. - These organs digest and absorb food. ¢ Accessory Organs: - Consists of teeth, tongue, salivary glands, liver, gallbladder, and pancreas. - These organs contribute to the process. Cah cain Salivary glands al cavity Pharynx Oesophagus Liver Stomach ball bladder Spleen Pancreas Lange intestine Small intestine Rectum 44 PROCESSES OF THE DIGESTIVE SYSTEM: Ingestion The process of putting food into the mouth. Propulsion The movement of food through alimentary canal including both swallowing and peristalsis (alternate muscle contraction/relaxation) Secretion Secretion of digestive enzymes and other substances liquefies, adjusts the pH of, and chemically breaks down the food. Mechanical Digestion The process of physically breaking down food by chewing and mixing. Chemical Digestion The process of chemically breaking down food into smaller molecules via enzymes in the stomach and small intestines. Absorption The movement of molecules from the digestive tract to adjacent blood and lymphatic vessels. Absorption is the entrance of the digested food (now nutrients) into the body. Defaecation The process of eliminating undigested material through the anus. STRUCTURE & FUNCTION OF ALIMENTARY CANAL: Mucosa: ¢ Mainly epithelium (stratified squamous in mouth/oesophagus/anus, simple columnar in stomach/SI/Ll) ¢ Assists in absorption, secretion (mucus, enzymes, hormones), and protection (contains lymphoid tissue) Submucosa: ¢ Lies outside the mucosa ¢ It consists of connective tissue containing blood vessels, lymphatic vessels, nerves & elastic tissue. ¢ Very responsive to ANS Muscularis: ¢ It consists of skeletal muscle in the mouth and pharynx which aids in swallowing. ¢ It consists of smooth muscle in the rest of the digestive tract responsible for food movement (peristalsis) ¢ There are 2 layers in the small and large intestines, and 3 layers in the stomach. ¢ Outer Longitudinal Layer: propel food (peristalsis) ¢ Inner Circular Layer: for agitation and form valves. Serosa: ¢ Consists of connective and epithelial tissue ¢ Forms visceral peritoneum (serous membrane that lines the stomach, Sl, and LI. ¢ Provides protection 45 SALIVA: Produces 1000-1500mL/day Digestive functions of saliva are that it moistens/softens food so it can easily be swallowed. ¢ Six major & numerous minor salivary glands (secreted via salivary ducts) ¢ Saliva is regulated by the ANS through fear, excitement, food aroma, and chewing. « When we ingest food, chemoreceptors and mechanoreceptors in mouth send signals to brain. ¢ Consists of mostly water (approximately 98%). ¢ Also consists of Electrolytes, Mucus, Proteins. Enzymes (amylase, lipase), & antibacterial compounds STOMACH: ¢ Produces 2000-3000mL/day of Gastric juice ¢ Exocrine Glands: Mucous Cells (for protection) and Chief Cells (pepsinogen, secrete gastric lipase) ¢ Parietal Cells: HCI (turns pepsinogen into pepsin & infection defence), intrinsic factor (absorbs Vit B12) ¢ Rugae (inner layer of stomach) aids in digestion by stretching the stomach and help grip/move food. ¢ Alkaline Tide is increased pH of body fluids due to the loss of acid by secretion of gastric juices. SMALL INTESTINE: ¢ The site where all digestion is completed and absorbs the end product. ¢ Mucosa and Submucosa are modified to reflect the intestines functions in the digestive pathway. ¢ Epithelium: simple columnar cells bound by tight junctions (responsible for nutrient/electrolyte absorption) ¢ Intestinal Crypts: secretory cells that secrete intestinal juice (serve as carrier fluid for absorbing nutrients) LARGE INTESTINE: ¢ Absorbs water from remaining indigestible food matter & transmit the useless waste material from body. ¢ Makes essential products such as Vitamin K and removes wastes from the body. PANCREAS: ¢ Pancreatic juice consists mainly of water and contains enzymes that break down food and electrolytes * Secretion of pancreatic juice is regulated by local hormones and the parasympathetic NS. ¢ Pancreatic juice is regulated by neural stimuli , and more importantly, hormones. « When no digestion occurs the hepatopancreatic sphincter is closed and bile is released. ¢ The bile then backs up to the cystic duct into the gall bladder, where it is stored until it is needed. GALLBLADDER: ¢ The gall bladder stores and concentrates excess bile that is not needed immediately for digestion. ¢ Bile: Bile is a fat emulsifier. Bile does not usually enter SI until gall bladder contracts when stimulated. * 800-1000mL/day of Bile produced and is brown-green-yellow. ¢ Bile emulsifies fat and cholesterol dissolves in it for transport. ¢ Levels are lowest during fasting. When chyme enters SI, stimulates hormones (secretin) to increases bile. LIVER: ¢ The function of the liver is to store glucose as glycogen, and release as needed (metabolism) ¢ The site where bile is produced. ¢ It also detoxifies/removes drugs, hormones, ammonia, and synthesises bile and cholesterol. 46 DIGESTION OF NUTRIENTS: Protein: ¢ Begins in stomach (polypeptide > dipeptide > peptide > amino acids) ¢ Proteins are broken down to dipeptides and pepsinogen is turned into pepsin by HCI. Continues in SI « Pancreas secretes trypsinogen, and chymotrypsinogen into S| Enterokinase turns trypsinogen into trypsin, then trypsin activates chymotrypsinogen. ¢ Chymotrypsinogen then digest dipeptides into peptides Peptidase then degrade these to amino acids. Carbohydrates: ¢ Begins in mouth with salivary amylase, stops in the stomach and completed in small intestine ¢ Pancreatic amylase made in the pancreas, act in small intestine, breaking polysaccharides to disaccharide « Intestinal juice has enzymes (lactase, maltase & sucrase) which can break down disaccharides. * Once this is done, disaccharides are broken down to monosaccharides (glucose, fructose) Fats: ¢ Triglycerides are ingested and bile emulsifies fat droplets. ¢ This increases the surface area of fats so that lipase can act on them. * Once lipase acts it results in fatty acids & monoglyceride which occurs in the small intestine. HEPATIC PORTAL SYSTEM: Oxygenated blood brought to liver via hepatic artery, and deoxygenated taken away by hepatic vein. ¢ Hepatic Portal Vein brings blood full of digested nutrients from Gl tract to liver for storage/distribution ¢ Blood enters liver from heart and gut. * Oxygen, nutrients and some poisons (such as drugs) removed by cells. ¢ Products made by liver cells, or stored nutrients released here are carried by hepatic vein to rest of the body via the heart. DEFECATION: ¢ As faeces are forced into the anal canal, messages reach the brain allowing us to decide whether the external (voluntary) anal sphincter should open/remain constricted, to temporarily stop faeces passing. ¢ If defecation is delayed, reflex contractions end within a few seconds, and rectal walls relax. ¢ The defecation reflex is initiated again, until person chooses to defecate or urge becomes unavoidable. 47 METABOLISM: A series of chemical reactions which use or release energy, are controlled by the thyroid gland, and are enzyme-dependent. There are 2 main types of metabolism: Anabolism Catabolism * Build Up Compounds into Complex molecules = * Break Down Compounds into Simple molecules + Uses Energy (ATP) * Releases Stored Energy (ATP) « Makes Water (Condensation Reaction) * Uses Water (Hydrolysis Reaction) + Most energy lost as heat * Mostly occurs in Mitochondria * E.g. 2 amino acids forming a dipeptide * E.g. dipeptide splitting to form 2 amino acid molecules ATP (ENERGY): Adenosine Triphosphate consists of an adenosine molecule bonded to three phosphate groups and is present in all living tissue. The breakage of one phosphate linkage (forming ADP) provides energy for physiological processes (e.g. muscle contraction). ¢ Dephosphorylated State: Removal of phosphate groups from an organic compound via hydrolysis ¢ Phosphorylated State: Addition of phosphate group into an organic molecule via condensation. BASAL METABOLIC RATE (BMR): Is the rate at which heat is produced and the amount of kilojoules (kJ) burned at rest. (E.g. an average man requires a BMR of around 7,100kJ/day to maintain homeostasis). Basal Metabolic Rate is influenced by the following: Sex, Age, Hormones, Exercise, NS, Body Temp. & Food HORMONES: The hormones that regulate metabolism are the thyroid hormones (T3 & T4) released from the thyroid gland. Thyroid hormones stimulate diverse metabolic activities in most tissues, leading to an increase in BMR. One consequence of this activity is to increase heat production, which results from increased O02 consumption and rates of ATP hydrolysis. CELLULAR RESPIRATION: Are the metabolic reactions that convert energy from nutrients into ATP. Glucose (C6H1206) + Oxygen (602) = Carbon Dioxide (6COz) + Water (6H2O0) + Energy (ATP). GLYCOLYSIS KREBS CYCLE ELECTRON TRANSPORT Oxygen Required? No Yes Yes Location Cytosol Mitochondria (Matrix) Mitochondria (Cristae) Inputs Glucose Pyruvate (forms Aceytl CoA) Loaded Acceptors 2 Loaded Acceptors Oxygen Oxygen Outputs 2 Pyruvate 6 Carbon Dioxide 6 Water (H20) 2 Loaded Acceptors 10 Loaded Acceptors Unloaded Acceptors Energy Yield 2 ATP 2 ATP 32-34 ATP GLUCOSE: The human body requires glucose for some of its most important functions. Glucose serves as the primary energy source for the brain, and cells throughout the body. The energy also carries out nerve cell conduction, muscle contraction, active transport & produces chemical substances. Once the SI has absorbed glucose, the blood stream carries it to the liver where it is stored as glycogen or used as an energy source. 48 PATHWAYS OF METABOLISM: Lysis is breaking down, Genesis is forming/building up. Glycolysis: Breakdown of glucose by enzymes Gluconeogenesis: Formation of glucose from non-carb sources (proteins and fats) Glycogenesis: Formation of glycogen from sugar Glycogenolysis: Breakdown of glycogen into glucose. Lipogenesis: Formation of fats from lipids Lipolysis: Breakdown of fats/lipids into fatty acids. ABSORPTIVE & POST ABSORPTIVE STATE: Absorptive: When the Gl tract is full and anabolic processes exceed catabolism. Nutrients are r into the bl tream. Post Absorptive: When the GI tract is empty and energy comes from the breakdown of our body’s reserves. In the post absorptive state, glucagon needs to be released into the bloodstream to provide energy. Cortisol & Adrenaline promote lipolysis, gluconeogenesis and glycogenolysis. 49 DNA: Deoxyribonucleic acid is a chain of its subunits called nucleotides and is shaped in a double helix. DNA sequences contains genetic information and provides instructions for making proteins. Nucleotides: Are organic molecules that serve as the subunits of nucleic acids like DNA/RNA. Chromosome: Is a strand of DNA encoded with genes, humans have 46 (23 pairs). Gene: Functional unit of heredity. Are DNA codes for proteins. Mutation: When a DNA gene is damaged/changed, altering the genetic message carried by that gene. Allele: Different variants of the same gene (E.g. gene for eye colour, one is blue, one is brown). Heterozygous: Having 2 different copies, where one allele is dominant and the other recessive. Homozygous: Having 2 identical copies and have all the same genes in all the same places. Genotype: The genetic makeup of an organism (the entire set of genes in an organism). Can't see it. Phenotype: How genetic and environmental influences create anatomy and physiology of gene. Can see. DNA AND PROTEIN SYNTHESIS: ¢ DNA goes through a process called transcription (turns DNA into single strand of RNA) ¢« RNAcodons (sets of 3 RNA nucleotides) give the code for amino acids. « RNAcodons are decoded into amino acids that make amino acid chain (polypeptide) via translation. TX CHROMOSOMES: Humans have 46 chromosomes (23 from mother, 23 from father). There are 23 pairs and 2 copies of each (these two members are called homologous chromosomes). If you only had one chromosome then there is no way to reproduce, and any DNA mutations would be permanent as there would be no dominance/recessiveness between genes, making genetic diseases more common. ¢ Autosomes: Are the 22 pairs of chromosomes that are not sex chromosomes. *« Sex Chromosomes: 1 pair of chromosomes thats functions to determine sex. (Females XX, Males XY). X chromosomes are larger & carry more genes, therefore males may have a single copy of some genes. rH Row y IU Wet nd Ww el Wo oat aon 3 4 5 16 17 18 1% m “ ‘ ( 19 «62000 oséD y * 50