Exam one study guide
Exam one study guide POUL 4060 Benson
Popular in Avian Anatomy and Physiology
POUL 4060 Benson
verified elite notetaker
POUL 4060 Benson
verified elite notetaker
verified elite notetaker
SPTE 203 001
verified elite notetaker
verified elite notetaker
HES 1823 004
verified elite notetaker
Popular in Poultry science
This 18 page Study Guide was uploaded by cjenkins96 Notetaker on Sunday October 2, 2016. The Study Guide belongs to POUL 4060 Benson at University of Georgia taught by Drew Benson in Fall 2016. Since its upload, it has received 3 views. For similar materials see Avian Anatomy and Physiology in Poultry science at University of Georgia.
Reviews for Exam one study guide
Report this Material
What is Karma?
Karma is the currency of StudySoup.
You can buy or earn more Karma at anytime and redeem it for class notes, study guides, flashcards, and more!
Date Created: 10/02/16
Lecture 1 (The Evolution of Flight) Archeopteryx: a famous fossil recovered from a Bavarian limestone quarry that shows a “transitional” state between modern day birds and non-avian dinosaurs. o What characteristics are similar to modern day birds? Had feathers, a lightly-built body with hollow (pneumatic bones), a wishbone (furcular), and reduced fingers. o What characteristics are similar to reptiles (unlike modern birds)? They had teeth, three claws on each wing, a flat sternum (breastbone), belly ribs (gastralia), and along, bony tail. What is cladistics? A biological classification in which organisms are categorized based on shared derived characteristics that can be traced to a group’s most recent common ancestor and are not present in more distant ancestors. Based upon cladistics, from which dinosaur group did birds evolve? Theropod. What is an atavism? An evolutionary trait that has disappeared phenotypically but the gene sequence often remains, but is inactive. What is a vestige? A trait that was once functional and necessary and an organism evolved not to need it. o Be able to provide an example: Wisdom teeth Be familiar with the potential purpose of early feathers in dinosaurs. Insulation, camo, mating (social signaling), brooding, anti-predation. Provide a possible scenario for the development of feathers leading to the evolution of pennaceous feathers and flight. Insulation leaping parachuting gliding flight. Why would it make evolutionary sense to lose the ability to fly in certain situations? (evolution of flightless birds in New Zealand). Flight requires a high metabolic demand, a limit of weight, and many skeletal adaptations that would not be necessary without flight. Why would it make sense to gain the ability to fly in certain situations? To escape predation, find new niches, and expand feeding range. What avian order do Chickens belong? Galliformes o What is the largest avian order? Passeriformes, song birds Be familiar with the relationship between metabolic rate and size in birds. The smaller the bird, the higher its relative basal metabolic rate (BMR). What characteristics of bones in birds allows them to be both strong and light weight for flight? Fused bones, ossification. o The pygostyle is a fusion of the final caudal vertebrae that serve as an attachment site for restrices (tail feathers). o The unicate process is an example of an ossification in birds, not present in mammals. What muscle powers down stroke of wing? Pectoralis minor (supracoracoideus). Up stroke? Pectoralis major. Know the following bones o Atlas, Axis, occipital condyle, occipital lobe, incisive, mandible, sternum, uncinate process, vertebral ribs, sternal ribs, scapula, coracoid, clavicle, humerus, radius, ulna, carpometacarpus, phalanges, foramen triosseum or triosseal canal, ilium, ischium, pubis, pygostyle, patella, tibiotarsus, fibula, tarsometatarsus, phalanges, femur, hock joint, o Study “Skeleton of the Fowl” in laboratory handout. Provide at least one adaptive characteristic for flight provided by the digestive system, renal system, cardiovascular and respiratory system. o Digestive system: Birds digest food quicker to get rid of waste and make them lighter. o Renal system: Birds produce uric acid so they do not hold water. o Respiratory system: Birds have air sacs and hollow bones (pneumatic) to make breathing more efficient. o Cardiovascular system: A bird’s heart is large with a strong ventricular wall and its heartbeat is relatively fast compared to mammals and is inversely proportional in size. A chicken heart beats 250 times per minute. What advantage does being uricotelic (produce uric acid) provide the bird? There is no need for a bladder which would way down the bird and is great at water conservation. Lecture 2 (Feathers) Know the following vocabulary words: o Rhamphotheca: beak o Podotheca: scaly covering of foot o Apteria: featherless o Pterylae: has feathers o Calamus, Vane, Rachis, Barbs, Barbules, Barbicles (hooklets), Contour, Semiplumes, Filoplume, Down feather, Bristle Feather o Patagia: membrane/skin between body and wing o Remiges: flight feathers o Rectrices: tail feathers What is the oldest portion of a feather? Calamus. What is a blood feather? Usually a larger feather that has blood circulation through the shaft. How could you tell the difference between a Remiges and a Rectrices? The rachis of a restrices is down the middle and symmetrical on each side, while the rachis of the remiges is not centered. Restrices are also usually longer. Be familiar with the function, location of bristle feathers. Around the eyes to keep dust, dirt, etc. from entering the eyes. Be able to recognize Remiges (secondary and primary), Primary Coverts, Secondary Coverts o What function do coverts serve in relation to the remiges? Steering Lecture 3 (Skin and Bones) What role does the avian integument system play for birds? Defense line, thermal insulation, barrier, carries pigment, contains nerves, provides Vitamin D. How do birds dissipate heat? How can you tell if a bird is heat stressed? They pant and push their feathers up so they can release air and get fresh air in. Know the three different layers of the epidermis and how they differ from each other. o Stratum Germinativum: deepest, stem cells that provide keratinocytes for the epidermis, mitosis occurs here o Stratum spinosum: middle, large layer of increasingly flat keratinocytes that have cells that produce keratin that die as they move to the epidermis o Stratum corneum: top layer, stratified (stacked) keratinocytes epithelium (dead, scaly part), resists water loss, penetration, and abrasion What glycosaminoglycan is present in high amounts in the comb of roosters? Hyaluronic acid. What use could this glycosaminoglycan provide to the medical field? Hyaluronic acid is a natural chemical that acts as a lubricant to enable bones to move smoothly over each other and as a shock absorber for joint loads. What are some of the functions of the secretion from the uropygial gland? To help in pruning. To lubricate scales, keep feathers pliable, provide waterproofing, and keeps feathers together. What type of secretion is the uropygial gland? Lipid based secretion that is applied to feathers while birds are preening. What is a holocrine secretion? Holocrine secretions are produced in the cytoplasm of the cell and released by the rupture of the plasma membrane, which destroys the cell (apoptosis). Know the pathway for the production of active vitamin D 3 o What is the rate limiting step in this pathway? PTH Trigger to activate this step? UV Be familiar with Fowl pox, Marek’s Disease, Omphalitis and Bumblefoot o What causes each disease and how is each transmitted? Fowl Pox: caused through dander and mosquitoes Marek’s Disease: widespread tumors often spread by dander form cutaneous tumors Omphalitis: caused by sepsis of an egg Bumblefoot: staff caused by getting dirt into a cut or wound o Difference between dry and wet Fowl pox? Dry pox is not lethal and shows symptoms of raised wart-like lesions, while wet pox is identified by cancer-like lesions in mouth, pharynx, larynx, and trachea which is lethal because it causes difficulty eating and breathing. o What is an oncovirus? Virus that causes cancer Oncogene? Gene that causes cancer (both associated with Marek’s) o What management practices should be addressed if a flock has omphalitis? Husbandry, hatchery sanitation, breeder flock surveillance, and proper pre-incubation. Bumblefoot? Keeping litter clean, remove objects that cause injury, isolate birds with problems, and nutritional feed. Describe the skeletal adaptations that have occurred in the skeleton as flight evolved in the avian species. Center of gravity in center of body underneath each wing, skeleton is light, strength with light-weight skeleton. What modifications have occurred in the avian neck and head that allows for the rhamphotheca to be an effective organ for prehension? More cervical vertebrae that allows for more flexibility and one occipital condyle which allows head to turn all the way around. Know the different ossifications that occurred that occurred as an adaptation to flight. Diffusion of wing bones (carpometacarpus) and synsacrum (fused portion of the vertebral column), the pygostyle. Be able to recognize the following bones on a skeleton: Synsacrum, Ilium, Ischium, pubis, ulna, radius, humerus, coracoid, clavicle, atlas, incisive, mandible, tarsometatarsus, tibiotarsus, fibula, femur, uncinate process, carpometacarpus, sternum, pygostyle, scapula, Foramen triosseum, Be familiar with the following terms: cortical bone, spongy bone, medullary cavity, Periosteum, endosteum, epiphyseal plate, articular cartilage, diaphysis, epiphysis, metaphysis, osteoid, lacunae, osteon, canaliculi, osteocytes, osteoblast, osteogenic cells, o Diaphysis: Extended tubular shaft o Epiphysis: Expanded areas at each end o Metaphysis: Narrow zone between diaphysis and epiphysis o Medullary cavity: Central cavity of bone shafts where red bone marrow (or yellow) is stored. Has walls composed of spongy bone and lined with endosteum o Periosteum: Dense irregular connective tissue that covers the outer surface of all bones, provides blood supply to the body of the marrow, attachment site for muscles. o Endosteum: Thin layer of reticular connective tissue that lines the internal marrow cavity, covers spongy bone and lines the canal system in compact bone. o Epiphyseal plate: Hyaline cartilage that separates the marrow spaces of the epiphysis and diaphysis, where the bone can grow in length. o Articular Cartilage: The joint surface where one bone meets another is covered with this layer of hyaline cartilage o Cortical bone: compact bone o Spongy Bone: open network of struts and plates o Lacunae: empty spaces o Osteon: functional unit of the bone o Caniculi: form pathways for blood vessels, exchange nutrients for water o Osteoblast: synthesize collagen, alkaline phosphatase, and osteocalcin o Osteogenic cells: precursor to osteoblast Know how both hydroxyapatite and the osteoid work together to make the bone matrix both flexible and highly resistant to shattering. The osteoid secretes type one collagen which allows for flexibility. Hydroxyapatite crystals are very hard and can withstand compression. o How would a bone behave in absents of adequate hydroxyapatite? The bone would be very flexible; however, would not be able to withstand pressure. What are osteoprogenitor (osteogenic) cells and where are they most commonly found in the bone? Ostogenic cells are stem cells that develop from embryonic mesenchymal cells and then give rise to other bone cell types. They are found in the endosteum and inner layer of the periosteum. They multiply and go on to become the osteoblast. Explain the difference between compact and spongy bone and describe their spatial relationship to each other. Compact bone is the firm, rigid outer layer of bone composed of osteons and hydroxyapetite. Spongy bone is the porous inner bone composed of trabeculae that houses marrow. Be able to describe three or more functions of the skeletal system other than supporting the body and protecting some of the internal organs. Works as part of the respiratory system (pneumatic bones), source of calcium, blood cell production. How does an osteoblast become an osteocyte? Osteoblasts surround themselves in bone matrix to become an osteocyte. Most osteocytes of an osteon are far removed from blood vessels but still receive blood borne nutrients. Explain how this is possible. Be able to label the different anatomical structures on a histograph of an osteon. (Slide 27) Describe the five zones of a metaphysis and the major distinctions between each. o Zone of Resting Chondrocytes: hyaline cartiledge on the epiphyseal (proximal) side of the plate o Zone of Proliferation: chondrocytes undergo rapid mitosis which elongates the bone o Zone of Hypertrophy: chondrocytes enlarge and begin to secrete alkaline phosphatase (calcification of matrix) o Zone of Calcification: chondrocytes are walled off in a calcified matrix, chondrocytes under apoptosis which means death o Zone of Ossification: osteoclasts (chondroclasts) break down the calcified matrix, osteoblasts begin forming the spongy bone Be able to describe how chondrocytes progress through each zone culminating with the formation of spongy bone (a spicule). How does Wolff’s law explain why cage reared layers may be more susceptible to osteoporosis then birds in an aviary? Greater physical stress placed on a bone at a particular site results in more bone deposition by osteoblast. Thus, due to the inactivity of cage layers, more physical stress is placed on their bones and it results in more bone deposition causing bone fragility and susceptibility to fracture (osteoporosis). What is appositional growth and how does it occur? Appositional growth is the growth in diameter of the bone (or growth in width). This occurs in response to pressure. Be familiar with how the following hormones interact with bone: PTH, calcitonin, 1, 25 dihydroxycholecalciferol, Growth hormone, thyroid hormone, glucocorticoids. What is medullary bone? What stimulates osteoblast to change from secreting cortical bone to producing medullary bone? In female birds, meduallary bone is stimulated by the synergistic action of androgens and estrogens, accompanying the maturation of the ovarian follicle. It acts as a liable reservoir for the supply of calcium for eggshell production. Know the questions form Hen Biology Question Assignment on EcL. How can you tell a difference between TD and rickets? By testing for PTH receptor regulation. With rickets, there is a lack of vitamin D and therefore a lack of calcium which results in excessive PTH levels which leads to the downregulation of the receptor. In TD, normal expression of PTH-r is observed. Hen Biology When do osteoblast change from forming lamellar cortical bone to medullary bone? At the onset of sexual maturity. o What is the purpose of medullary bone? To act as a source of calcium for egg shell formation. o Why is medullary bone functionally weaker than structural bone? Because the form of a woven bone is based upon an irregular arrangement of collage fibrils and much of medullary bone is present in isolated spicules. Explain why structural bone content of the hen declines during lay? Osteoclastic reabsorption of structural bone. How can exercise potentially increase bone strength? It stimulates structural bone growth during rearing. What is osteomalacia? A nutritional disease caused by nutritional deficiencies of calcium, phosphorus, or cholecaliferol and can ultimately lead to greater severity of osteoporosis. Why might dietary calcium from a particulate rather than a powered form improve egg shell and bone quality? Particulate calcium sources remain in the digestive system longer at night and can provide a greater dietary source of calcium during the period of shell formation thus making birds less dependent upon bone mobilization to provide calcium for egg shells. By what process do long bones widen? Intramembranous ossification. Why isn't the statement “osteoporosis occurs in hens because they deplete their bones by laying so many eggs” not entirely correct? It’s not that their bones deplete, rather that the structural bone is replaced with medullary bone. Avian Respiratory System Avian Respiratory vs Mammalian o Air Sacs (9 of them) Cervical (2), Interclavicular (1), Anterior Thoracic (2), Posterior Thoracic (2), Abdominal (2) o One way airflow with cross-current exchange: Parabronchi o Higher respiratory volume (15% for birds vs 7% for mammals) o No diaphragm (breathing dependent on inspiratory and expiratory muscles that extend the sternum and open the ribs to increase area (or decrease pressure) of thoracic cavity. This is why you want to be careful when holding chicks….often kids may squeeze the birds and prevent them from being able to breath. o Alveoli (Mammals, diffusion) vs Parabronchi (birds, counter- current exchange) o Expandable lungs in mammals vs the rigid structure in birds. Rigid structure that does not expand nor contract during the respiratory cycle. This feature together with the absence of the diaphragm indicates that ventilation is accomplished by different mechanisms compared to mammals. Know the term cardiopulmonary: Having to do with heart and lungs Know the right side of the heart pumps to the pulmonary circulation through pulmonary arteries (O po2r), while the left side of the heart pumps to the systemic circulation via the aorta (O r2ch) after receiving blood from the pulmonary circulation. What function do the Concha (meatus passageways) serve for respiratory system? Know the following terms: Nares, Choana, glottis, trachea, syrinx, primary bronchus, o Nares: nose o Choana: median fissure in the palate which connects the orpharynx inside the mouth with the nasal cavity. Birds do not have a soft plate as mammals do. Numerous projections or papillae are found at the edge of the choana. o Glottis: hole chickens have separating the mouth and trachea o Trachea: tube that provides pathway for air from glottis to syrinx. Has hyaline cartilage which makes ring looking structure and provides collapsing quality o Syrinx: structure formed by terminal part of tracheal that allows bird to make sound when expiring o Primary bronchus: one primary bronchus from the trachea enters each lung, narrowing as it travels through, and communicates with abdominal air sac. Remember: tracheal cartilage rings completely encircle the trachea and this is different from the C rings in human trachea. Be able to trace air as it travels through the respiratory system. Start witndthe first inspiration through the nares and end with the 2 expiration out the trachea. Paleopulmonic parabronchi vs. Neopulmonic parabronchi: the collection of paralleled parabronchi is referred to as paleopulmonic. Some of the parabronchi are not organized with regular parallel stacks and have random organization, these are called neopulmonic parabrochi. 25% of the parabronchi are neopulmonic. Be familiar with how cross-current gas exchange occurs (know that O 2 rich air passing from the posterior parabronchi exchanges with O2 poor blood flowing in an anterior to posterior manner….”Cross- Current”): in the avian lung, oxygen diffuses by simple diffusion from the air capillaries into the blood and CO2 from the blood into the air capillaries. They travel at right angles to each other, which is referred to as cross-current flow (very efficient). Be familiar with Henry’s law: Henry’s law states that the amount of a gas that dissolves in liquid is directly proportional to the partial pressure of that gas. o How would altitude impact Henry’s law: The gas dissolved in liquid would be much less, due to the fact that the partial pressure of gas is much lower at high altitudes. Even though the partial pressure difference is greater for O than for 2 CO 2,explain why CO exc2anges at near an equal rate (consider Henry’s law). Equal amounts of O2 and CO2 are exchanged across the respiratory membrane because CO2 is much more soluble and diffuses more rapidly. Terms: Hemoglobin, oxyhemoglobins, deoxyhemoglobin, heme, o Hemoglobin: molecule specialized in oxygen transport o Oxyhemoglobin (HbO2): O2 is bound to hemoglobin o Deoxyhemoglobin (HHb): hemoglobin with no O2 o Heme: cofactor consisting of a Fe2+ ion contained in the center Know the tree different forms of CO tra2sport in the blood. 70% comes from carbonic acid, 23% from carbamino compounds, and 7% dissolved in the plasma. Know the formula for formation of carbonic acid and responsible enzyme + - o CO + 2 O 2CH O H2+3HCO 3 o Carbonic Anhydrase (where is this enzyme located?) It is located within the hemoglobin (red blood cells), interconversion of CO2 and carbonic acid. How/Why is Carbon Monoxide (CO) toxic? It has a much higher binding affinity for hemoglobin than oxygen. It takes the place of oxygen on hemoglobin and causes the tissues to become oxygen starved and die. o Treatment? Fresh air immediately. What is the Bohr effect and how is it significant concerning Oxygen unloading? Active tissues have increased CO2 which lowers the pH of the blood promoting O2 unloading. H ions weaken the bond between hemoglobin and oxygen. Provide three factors that adjust oxygen unloading for metabolically active tissues. Generates extra CO2, raises H+, and lowers the pH of the blood. What are some unique adaptations of birds who travel (live) at high altitudes? Hemoglobin has a higher efficiency of CO2, mitochondria are placed closer to capillaries, O2 does not have to diffuse to reach mitochondria, and higher levels of creatin kinase. o What is the significance of mitochondria placement and creatine kinase have in this adaptation to high altitude? Creatine kinase does not have to shuttle ATP from mitochondria to sarcomere as far if they are closer together. This means there will be a higher rate of O2 unloading, which is necessary since the pressure at high altitudes. o What is the mucociliary escalator and why is it significant? A major barrier against infection. Microorganisms hoping to infect the respiratory tract are caught in the sticky mucus and moved up by the mucociliary escalator. In poultry rearing, what can significantly compromise the mucociliary escalator. Anesthesia Lecture Know who Crawford W. Long is: A man from UGA who was the first to use anesthesia to remove a neck tumor from a patient in 1842, but failed to publish on the matter so he did not receive credit. What was a drawback to the initial anesthetic diethyl ether? It was extremely flammable and often lead to explosions, it irritates the respiratory tract, and has incidence of nausea and vomiting during induction and post-op. Chloroform? It shows hepatic and cardiac toxicity. Why is isoflurane a better anesthetic: It is a halogenated ether and is safer because it is non-flammable. Be familiar with the general characteristics of general surgical anesthesia: Loss of consciousness, pain sensation (analgesia), and memory (amnesia), muscle relaxation, and a decrease in heart rate, blood pressure, and respiration rate. What is the resting membrane potential of neurons? -70 mV What is depolarization (when the membrane potential inside the cell increases), repolarization (a return to resting potential), and hyperpolarization (when the membrane potential inside the cell decreases). What is threshold for voltage-gated Na channels? -55 mV At what voltage are voltage-gated Na channels deactivated? +30 mV At what voltage does K channels open for repolarization? +30 mV During repolarization, the resting membrane is overshot to this voltage known as hyperpolarization. How is the membrane potential restored after an action potential? K+ channels open allowing K+ to exit the cell and makes the voltage drop to resting potential. Know how neurons code for stimulus intensity: a higher stimulus will make AP’s occur more frequently o Frequency and recruitment (what is recruitment?) When a stronger stimulus activates more neurons in a nerve. Movement of an action potential down an axon relying on cable properties is inefficient, what is present, anatomically, that helps propagate the action potential quickly? Schwann cells make up the myelin sheath surround axon and make sure ions are only transferred in and out at the node of ranvier. o What is saltatory conduction? Action potentials moving down the axon in one direction, from cell body to synaps What is an EPSP and how are they generated? An excitatory postsynaptic potential. Depolarization of postsynaptic membrane due to Na+ ions flowing into the cell. This can cause action potential if enough ions flow in. o What is the axon hillock and why are EPSPs important here? The axon hillock is what the depolarization must overcome for action potential to be triggered. If enough Na+ ions fill cell body they will cross axon hillock causing voltage gated K+ channels to open and action potential to be induced What is an IPSP, provide one way that they can be generated? Inhibitory postsynaptic potentials. Caused by flow of negative ions into cell. This activates inhibitory neurotransmitters Starting with an EPSP in the soma of a neuron body, trace how that EPSP would ultimately result in the release of acetylcholine into the synaptic cleft. o Be sure to include the following in your answer: axon hillock, voltage-gated Na channels, axon, voltage-gated Ca channels, synaptotagmin, SNARE, exocytosis. o Stimulation causes Na+ to enter dendrites and cell body. this is EPSP. o If EPSP depolarizes cell enough (-55mV) the Na+ ions cross axon hillock triggering the opening of voltage gated Na+ channels => AP o AP moves down Axon and Na+ channels and K+ channels (after 30mV is reached) are only found at nodes of renvier in between myelin sheaths. o At the presynaps the Na+ ions open the voltage gated Ca2+ channels allowing for Ca2+ to enter and bind with synaptotagmin protein. o Together Ca2+ and synaptotagmin remove SNARE protein (which blocks vesicles with ACh form undergoing exocytosis) o Once SNARE is removed vesicles exocytose into synapse and release ACh What is the nicotinic Ach receptor and how does it generate an EPSP? o ACh binds to ligan gated channels on postsynaptic neuron (nicotinic ACh receptor) o Channels open, Na+ can enter cell, K+ can exit o Ap is created if EPSP is enough What is tetrodotoxin? Curare? How does their toxicity differ, how are they similar? Tetrodotoxin is a poisonous compound present in the ovaries of certain pufferfishes and it blocks Na+ channels. Curare is the poison used by South Americans that block Ach at the neuromuscular junction. What type of receptor is the muscarinic Ach Receptor? Nicotinic o In cardiocytes (heart cells), how does Ach lead to a slowing of heart rate? Ach binds to muscarinic receptors in the SA node. This opens up K+ channels and K+ flows out creating IPSP. What is the function of acetylcholinesterase (AChE)? Degrades Ach in synaptic cleft to acetate and chlorine which can be recycled to for Ach. o How is this related to nerve or sarin gas? It blocks AchE which blocks the nerve’s ability to quit sending signals and muscles cannot relax and stay contracted. This was used in WWI and often lead to a soldier’s death. Muscle Lecture Know the difference between the origin and insertion of a muscle. The origin does not move while the insertion of a muscle where the bone moves Know the difference between extensor and flexor muscles: Flexor muscles decrease the angle between two bones at the joint and the extensor increases the angle between two bones at a joint. Anatomical terms to know: Fascia or Epimysium, muscle fiber, sarcomere, sarcolemma, sarcoplasmic reticulum, and fascicles. o Fascia (Epimysium): connective tissue continuous with the tendon o Muscle fiber: connective tissues from this outer sheath extends into the body of the muscle, subdividing it into muscles Know A band (heavy, dark, myosin) vs. I band (light, actin) Know what the motor end place is where the neurotransmitters bind to stimulate muscle contraction (*where nicotinic receptors reside on sarcolemma) What is a motor unit? A single motor neuron and all of the muscle fibers that it innervates o Know that the axon of the motor neuron leave the ventral root horn in its travel to the muscle fibers it innervates On a sarcomere know: o A band: myosin and actin o H zone: myosin only o I band: actin only o Titan: allows for recoil of the muscle cell after contraction o Z disc: ends of sarcomere anchor for actin I bands and H Zone shorten, A bands do not Know the function of titan Myoflilament structural anatomy: o Know the following: Troponin (C), tropomyosin, actin, myosin Be able to provide the sequence of events that occurs during cross- bridge formation. Why does rigor mortis occur in dead animals? The muscle contracts when the myosin shifts, but the lack of ATP prevents it from detaching, and the muscle remains contracted. Where does most of the Calcium in the sarcoplasm originate: SR Know Treppe, temporal summation, complete tetanus and fatigue o Treppe: A series of stimuli is delivered to the skeletal muscle; there is an increase in the tension developed during each twitch until a uniform tension per contraction is reached. This is due to an increased availability of Ca2+. o Summation: If two or more stimuli are delivered rapidly then each twitch will be greater than the first. The tension developed here is much greater than during the single twitch. o Incomplete Tetanus: Individual responses fuse into one continuous contraction. It is incomplete tetanus when there are periods of incomplete relaxation between the summated stimuli. o Complete Tetanus: During complete tetanus, there is no relaxation between stimuli. The tension is much, much greater than individual twitch. o Fatigue: Fatigue occurs when there is a shortage of substrate. This results in a lack of intracellular energy sources to fuel muscle contractions. Be familiar with the different muscle types: Type I and Type II o Type 1, slow twitch: The slow muscles are more efficient at using oxygen to generate more fuel (known as ATP) for continuous, extended muscle contractions over a long time. They fire more slowly than fast twitch fibers and can go for a long time before they fatigue. o Type 2, fast twitch: Because fast twitch fibers use anaerobic metabolism to create fuel, they are better at generating short bursts of strength or speed than slow muscles. However, they fatigue more quickly. o Fast twitch fibers generally produce the same amount of force per contraction as slow muscles, but they get their name because they are able to fire more rapidly. Having more fast twitch fibers can be an asset to a sprinter since she needs to quickly generate a lot of force. o Know their specializations and be able to differentiate between them. o Which is dark meat, white meat? Increased blood flow due to muscle usage makes dark meat darker in appearance and more flavorful. o What is Myoglobin? The oxygen storage protein that functions similarly to hemoglobin What is myostatin? It is a amyokine, a protein produced and released by myocytes that acts on muscle cells' autocrine function to inhibit myogenesis (muscle cell growth and differentiation). o How is this related to loss of muscles with age? To start to make more myostatin as you age. o What are satellite cells? Precursors to skeletal muscle cells. Muscle Myopathies What two myopathies in modern broiler chickens are of increasing concern due to their unappealing appearance of the breast fillets? White striping (WS) and woody breast (WB). What is driving the increase in live market weight that may be a factor in the increasing incidence of these myopathies? It has been driven by the shift in consumers purchasing a whole bird carcass to cut-up parts with the processing sector favoring larger birds. Deficiency in this vitamin can present similar carcass characteristics as WS? Vitamin E What is DPM or green muscle disease? A condition affecting the supracoracoideus muscle in the broilers and the turkeys. o Why does ischemia of the muscle occur during DPM? There is not enough room for the muscle to expand. o What is creatine kinase? How might selection for higher levels of creatine kinase decrease the incidence of DPM? What is Pale Soft Exudative (PSE) Meat? A condition where the meat shows a pale color, soft consistency, and poor water holding capacity. o What is a hypothesis for why PSE occurs in meat? It may be genetic or due to environmental factors related to pre-slaughter stress. What is a common link between PSE, WS and WB? The increase accumulation of calcium ions. Questions that you SHOULD be prepared to answer on the discussion portion of the test! 1. The archaeopteryx fossil was a fascinating discovery in 1861. Provide the characteristics that this fossil shared with modern day birds? With reptiles? Additionally, what other evidence aside from this fossil do we have showing that birds are direct descendants of theropods? The archaeopteryx fossil had feathers, a lightly-built body with hollow (pneumatic bones), a wishbone (furcular), and reduced (fused) fingers similar to that of modern day birds. Unlike modern birds, the archaeopteryx fossil had teeth, three claws on each wing, a flat sternum (breastbone), belly ribs (gastralia), and a long, bony tail like that of a reptile. It is believed that birds are direct descendants from theropods. Like birds, theropods laid eggs and were involved in brooding and had a respiratory similar to modern days equipped with air sacs. Theropods also developed elongated forelimps linger than their hindlimbs that allowed for flight, similar to modern birds. 2. Birds have made several physiological and anatomical adaptations for flight. Please provide describe distinct anatomical/physiological adaptations that evolved for avian flight. A bird’s skeleton is light weight but fusion of bones into ossifications give it great strength for flight. Birds have wings, feathers, and elongated forelimbs adapted for flight. Birds have strong muscles including a massive pectoral muscle for flight that is 30-40% of its body weight. Physiologically, the digestive system can rapidly move food through the gut to get rid of waste and become lighter for flight, in the circulatory system the heart is very large (40% larger than that of mammals) and can beat very fast, the respiratory system has air sacs throughout the body, no diaphragm, and rigid lungs equipped for breathing at high altitudes, and the renal system contains large kidneys (double the size of mammals), no urinary bladder which makes the bird lighter, and uric acid which conserves water all for the purpose of flight. 3. Name the air sacs present in the chicken and then provide the pathway of air through the avian respiratory system. Start with entrance into the nares during the 1st inspiration and end with the exit from the trachea. How is this more efficient than mammalian respiration? There are 2 cervical air sacs, 1 intraclavicular air sac, 2 anterior thoracic air sacs, 2 posterior thoracic air sacs, and 2 abdominal air sacs. Recite chart. Birds have a higher respiratory volume, at 15%, than that of mammals at 7%. Birds have a rigid structure that does not expand nor contract during the respiratory cycle. This, paired with the absence of a diaphragm and the addition of air sacs, makes breathing for birds more efficient than mammalian respiration. 4. Starting with an EPSP in the soma of a motor neuron, provide the sequence of events that culminates with the release of acetylcholine at the neuromuscular junction. 1. EPSP is generated in cell body of motor neuron in the ventral root horn. 2. EPSP sufficient enough to generate opening of voltage gated Na+ channels at axon hillock. 3. Action potential travels down axon via salutatory conduction (between Schwann cells) at nodes of Ranvier (where voltage gated Na+ channels reside). 4. Action potential arrives at the end of axon and opens voltage gated Ca++ channels. 5. Ca++ floods into cells and binds to synaptotagnnen, forming Ca++- synaptotagnnen complex. 6. Ach is held in pre-synaptic vesicles at synaps by a SNARE protein complex. 7. Ca++-synaptotagnnen disrupts SNARE complex resulting in exocytosis of Ach. 8. Ach binds to nicotinic-Ach receptors on membrane of a muscle. 9. Na+ enters and generates and EPSP that can open voltage gated Na+ channels. 10. Action potential travels down t-tubule where it can open voltage gated Ca++ channels. 11. Voltage gated Ca++ channels are linked to Ca++ channels in sarcolemma causing Ca++ to exit SR and flood cytoplasm. 5. Explain why the myosin heads don’t bind to the actin when the muscle is relaxed. Then, provide a step-by-step explanation of how depolarization of the muscle fiber plasma membrane by Ach leads to the binding of the myosin heads to actin (explain excitation-contraction coupling). 1. Ca++ efflux from SR. 2. Ca++ binds to troponin C and causes a conformational change that moves tropomyosin to expose a myosin binding site on actin. A cross bridge is formed. 3. ATP binds to an ATP binding site on myosin where myosin ATP-ase splits ATP into ADP and pi. 4. Splitting into ADP and pi causes the myosin head to “cock” which is the high energy form of myosin. 5. In the “cocked” position, the myosin then binds to actin. 6. Upon binding, pi is released causing the “power stroke” which shortens the sarcomere. 7. In order to disengage from actin, a new ATP must bind (the displacement of ADP). 8. Ca++-ATP-ase pumps bring Ca++ back into the SR and binds to calsecrestin. 6. Provide the pathway for the synthesis of active Vitamin D (1, 25 dihydroxycholicalciferol). 7. Compare and contrast the differences between smooth muscle, cardiac muscle and skeletal muscle contraction. Cardiac and smooth muscle is involuntary, regulated by autonomic nervous system, and the contractions in these muscles are due to myosin and actin cross bridges stimulated by calcium. The cardiac muscle is striated and the contractions occur by means of sliding thin filaments, and unlike skeletal muscle, these fibers are short, branched, and connected via intercalated discs. The smooth muscle does not have sarcomeres and has long actin filaments attached to dense bodies, it has some myosin filaments, and has an arrangement that allows contraction even when greatly stretched. 8. Explain how the contraction of a myocardium is analogous to a skeletal muscle twitch, and why the myocardium cannot exhibit summation and tetanus. 9. Describe the three factors that adjust oxygen unloading for metabolically active tissues. Oxygen unloading is when H+ binds to HbO2 reduces its affinity for O2. Three factors that adjust oxygen for metabolically active tissues includes the Bohr effect, the tendency to make hemoglobin realease oxygen, and when HbO2 arrives at systemic capillaries 97% saturates and leaves at 75% saturated. 10. Compare and contrast the differences between Type I and Type II muscle fibers. Type I muscle fibers are the slow twitch fibers and has a slower myosin ATPase. Type I has great endurance in the postural muscles and have a high oxidative capacity that relies on aerobic respiration with far more mitochondria, more capillary infusion, and myoglobin. Whereas, the Type II muscle fibers have fast myosin ATPase and is therefore faster with a more powerful reaction. Also, type II muscle fibers rely on glycogen with anaerobic respiration. Because type II muscle fibers are faster, they fatigue much faster and have a lower capillary infusion with less mitochondria. 11. Draw a sarcomere in a relaxed muscle and a sarcomere in a contracted muscle and label the following bands in each. What is the significance of the differences in your drawings? a. A band: myosin and some actin overlap. During contraction, nothing happens. b. H zone: myosin only. During contraction, gets smaller. c. M line: d. I band: actin only. During contraction, it shortens. e. Titan: allows for recoil of muscle during relaxation f. Z disc: marks end of sarcomere, anchor for actin. During contraction, it shortens 12. Know the sequence of events that leads to contraction in a smooth muscle, starting with opening of voltage-gated Calcium channels and ending with the detachment of myosin from actin. 1. Calcium enter primarily through voltage gated calcium channels through the plasma membrane. 2. Calcium binds to calmodulin and activates myosin light chain kinase. 3. Myosin light chain kinase phosphoralates myosin light chains which allows myosin to form cross-bridges with actin to initiate concentration. 4. Stimulation is graded and more stimulation allows for more calcium which allows for stronger contractions. 5. Contraction are slow and sustained and may enter a latch state. 6. Calcium is pumped out ising calcium ATPase using active transport pumps. 7. Calmodulin dissociates from myosin light chain kinase. 8. Phosphate groups are stripped from the myosin by myosin phosphatase. 13. Describe how Wolff’s law can explain why cage reared layers are more susceptible to osteoporosis then birds reared in an aviary. Greater physical stress placed on a bone at a particular site results in more bone deposition by osteoblast. Thus, due to the inactivity of cage layers, more physical stress is placed on their bones and it results in more bone deposition causing bone fragility and susceptibility to fracture (osteoporosis). 14. Describe the etiology of deep pectoral muscle disease (green muscle diease). Why do you think a section for increased levels of creatine kinase can decrease the incidence of DPM? 15. Explain why there has been an increase in the incidence of muscle myopathies in the broiler industry over the past 10 years. Over the past 10 years, there has been a driving increase in live market weight of broilers because consumers have made a switch from wanting whole-carcass birds to cut-parts so the processing sector favors larger birds which is a major cause of the increasing incidence of muscle myopathies. 16. Describe what is occurring in rigor mortis? How is this process of rigor mortis related to meat quality during processing? Rigor mortis causes a bird to stiffen after it dies because all of the ATP is used and after death, the bird cannot produce anymore. Rigor mortis can cause meat quality to be worse. If a muscle undergoes rigor mortis, it would be more tough and less tender therefore making the consumer unhappy.
Are you sure you want to buy this material for
You're already Subscribed!
Looks like you've already subscribed to StudySoup, you won't need to purchase another subscription to get this material. To access this material simply click 'View Full Document'