The Dissection of Vertebrates. Book • 2nd Edition • Authors: Gerardo De Iuliis and Dino Pulerà. Browse book content. About the book. Search in this book. Request PDF on ResearchGate | The Dissection of Vertebrates | The Dissection of Vertebrates provides students with a manual combining pedalogical effective. The Dissection of Vertebrates covers several vertebrates commonly used in providing a transitional sequence in morphology. With illustrations on seven.
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download The Dissection of Vertebrates - 2nd Edition. Print Book & E-Book. Price includes VAT/GST. DRM-free (EPub, PDF, Mobi). × DRM-. The Dissection of Vertebrates, Second Edition, provides students with a manual that combines pedalogical effective text with high-quality, accurate, and. the dissection of vertebrates pdf the dissection of vertebrates second edition Dissection (from Latin dissecare "to cut to pieces"; also called anatomization) is the.
Such an arrangement in mammalian limbs led to increased agility. Mammals have retained the general pattern of the reptilian epaxial musculature but have greatly reduced the segmentation present in reptiles.
Changes in mammalian locomotion have resulted in altered proportions and specific functions of related reptilian muscles. Modification of some bones, especially the distal ones, has occurred in some mammals. Compared to reptiles, mammals have undergone major changes in their limb structure, and pelvic and pectoral girdles, resulting in reduction in size of the ventral adductor muscles in the pectoral region, which are necessary in supporting and raising the body from the ground as seen in reptiles.
There is also reduction in size of the tail musculature. Further, the shoulder joint is supported by enlarged dorsal muscles which have benefited also from migration of some ventral muscles. Several muscles have evolved in mammals which are lacking in other vertebrates. The diaphragm is a dome-shaped muscle wall that completely separates the thorax from the abdomen and is the most important muscle of inspiration in mammals.
The cutaneous muscles panniculus carnosus are a sheath of muscles found in the fasciae of many mammals but not much developed in amphibians and reptiles except for the occasional presence of a few fibers in the pectoral musculature. These muscles are poorly developed or absent in primates and permit local movements of skin independent of deeper muscles. They also play a role in heat generation in response to cold stress through shivering. They enable animals such as armadillos to roll into a ball when endangered.
In marsupials, a sphincter portion of this muscle surrounds the entrance to the marsupium. The arrector pili muscle is associated with hair and causes erection of individual hairs when it is cold, thereby improving insulation of the body by trapping air. Jaw muscles, e. Related to these muscles during evolution is the tensor tympani from the adductor mandibularis. The cutaneous musculature of the face mimetic muscles , derived mainly from surficial sheets of hyoid musculature and spread on the face, is particularly well developed in carnivores and primates, especially man.
These muscles enable primates, especially man, to express emotions without talking. The surviving mammals belong to two subclasses: Prototheria monotremes which includes the platypus and echidnas of Australia and New Guinea and Theria marsupials and placentals.
The monotremes Gr. Marsupials infraclass Metatheria differ from placentals infraclass Eutheria in many skeletal and dental features. Eutherian mammals have undergone adaptive radiation to occupy different environments.
For example, in sirenians dugongs and manatees that live in water, the pelvis is vestigial and the hindlimbs lacking while the forelimbs are modified into flippers, as is the case with many marine mammals. The equivalent muscles in these modified body regions have become vestigial or modified.
The presence of wings in bats necessitated development of patagial muscles that are slips of pectoral muscles which insert on the skin of the wing membrane. Vertebrate musculature may be classified using three main approaches; structural, functional or a combination of these two approaches. In general, the structural approach takes into account the morphological characteristics of a muscle tissue, in particular the arrangement of myofilaments contractile protein filaments within a muscle fiber.
Under this scheme two types of muscles have been identified: striated with typical crossbanding pattern or striations examples include skeletal and cardiac muscles and smooth in which the myofilaments do not form a definite cross-banding pattern and hence there are no striations. The functional approach relies mainly, however, on the type of innervation and accompanying response of the muscle tissue on neural stimulation.
In this regard, voluntary muscles, essentially innervated by somatic nerves, are under conscious control by the individual and hence respond at will. All skeletal muscles fall in this category.
All smooth and cardiac muscles belong to this latter group. These are referred to as striated voluntary muscles, e. These are striated involuntary muscles, e. These are nonstriated involuntary muscles, e. Smooth Muscles Smooth muscles generally occur in the skin and walls of tubular organs with their associated glands.
Smooth muscle cells are long and fusiform spindle shaped with centrally located nuclei Figs. Often these cells assume an arrangement in a muscle tissue wherein the thin end of one cell is closely applied to the thick middle portion of the adjacent cells. Under ordinary circumstances, Fig. The epithelium of the duct ep is surrounded by a thick muscular wall formed by smooth muscle cells sm. The cells have elongated centrally located nuclei n X Unlike skeletal muscles, these protein myofilaments are highly unstable being assembled and disassembled as the need arises.
Based on the structure and functions, smooth muscles may be classified as: a multiunit muscles occurring mainly in the pilomotor muscles of the mammalian skin, nictitating membranes of the eyelids of frogs, ciliary body of the eye and blood vessels.
In this type of smooth muscle, the cells have no direct electrical contact with each other and the contraction of each fiber is initiated by an independent nerve branch terminating on each of the fibers.
Multiunit fiber contractions occur almost all at the same time. These contractions are stimulated by a neurotransmitter substance, usually acetylcholine, or pharmacological agents which mimic this neurotransmitter substance. The muscle cells here have a direct contact with each other and the contraction is elicited through propagation of electrical stimuli from one cell to the next through gap junctions or nexi.
The cells in this type of muscle are organized into definite bundles, each supplied by a nerve branch. As a result, contractions of muscle cells in this case are spontaneous, gradual and independent of neuronal control, as typically exemplified in peristalsis. Cardiac Muscles Cardiac muscles or myocardia arise from the splanchnic mesoderm associated with the developing heart tube. From early embryonic times, the muscle fibers contract rhythmically without fatigue and independent of any direct nervous stimulation; hence they are referred to as myogenic fibers.
The myocardial fibers Figs. Often, the fibers appear branched interlocking at their ends with each other to form a syncytium. This syncytial arrangement enables the cardiac muscles to contract as a unit. As in skeletal muscles, striations in cardiac muscles are due to the presence of alternating bands of actin and myosin filaments Figs.
Note the presence of sarcoplasmic striations within the cells X Z-lines mark the boundary between adjacent sarcomeres. The cell nucleus N is at the extreme left X 12, Occasional termination of nerve endings on the fibers forming the motor end plate M are encountered X Notice the orderly arrangement of myofilaments into bands, giving the cell its typical striations. Some of the bands recognized in this micrograph are: 1 A-band consisting of both actin and myosin filaments, 2 H-band made up of myosin filaments only, and 3 I-band comprising actin filaments only.
Actin filaments of the two I-bands from adjacent sarcomeres meet at the Z-line Z. X 25, For further details see Chapter 4. Intercalated disks At the interlocking ends where adjacent fibers meet, junctional specializations similar to the Z-line of skeletal muscle fibers with stairwell arrangements occur.
These junctional specializations are called intercalated disks Figs. These disks allow the spread of electrical activity from one cell to another, facilitating syncytial contraction of cardiac muscles. Since these disks receive the filaments of the I-band from both ends of adjacent fibers, they transmit mechanical energy of contraction from one cardiac muscle fiber to the next.
Impulse generation and conduction in cardiac uscles: Rhythmic contraction of cardiac muscles is a result of stimulation by electrical impulses generated at the sinoatrial node SAN or pacemaker situated at the junction of venae cavae and the right atrium. From the SAN, impulses spread to the atrioventricular node AVN located at the interventricular septum through three fiber tracts: ventral, middle, and dorsal internodal pathways Berne and Levy, From the AVN, impulses are carried by special fibers which, by and large, resemble myocardial fibers.
These fibers are called the bundle of His. Fibers of this bundle occur along the atrioventricular septum and divide into two main groups as His approaches the ventricles; the right bundle courses into the right ventricle and the left bundle into the left ventricle. The left bundle further divides giving rise to the left major and minor bundles. These fibers are continuous with the Purkinje fibers found on the ventricular walls on either side of the heart.
Electrical impulses from the bundle of His spread to the entire ventricular wall through the Purkinje fibers. These Purkinje fibers are generally larger than cardiac muscle fibers with centrally located nuclei and scattered peripherally situated myofibrils, sometimes shrinking toward the center.
They have numerous mitochondria and intercalated disks.
These impulse-conducting muscle fibers are referred to as modified cardiac muscles. Skeletal Muscles Skeletal muscles are generally responsible for voluntary movements in vertebrates. They are mainly found applied to the external surface of the skeleton and their contraction results in movements of joints or associated structures. Skeletal muscle cells or fibers have numerous peripherally located nuclei with conspicuously organized striations in the sarcoplasm Figs.
The striations occur as a result of alternating bands of thin actin and thick myosin filaments see Chapter 4 for details on contraction.
Contrary to cardiac muscles, cells of skeletal muscles do not show branching and anastomosis and contain abundant glycogen granules. Whereas these fiber types have distinct locations in fish, they occur in different proportions in muscles of other vertebrates depending on the type of contraction performed. Tonic Muscle Fibers These are very slow contracting muscle fibers that exhibit a continual partial contraction in a muscle.
They do not produce a significant response when stimulated with a single stimulus and show no recognizable contraction and movement, but do cause tautness as a result of contraction of a small number of the total muscle fibers in a muscle. Tonic muscle fibers are innervated by multiple nerves and show graded response to stimulation of different frequencies, leading to contraction in relays by groups of muscle fibers in a muscle. The fibers are important for maintaining posture as they can maintain isometric contractions economically since they have a very long cross-bridge cycle.
Muscles with less tone than normal are referred to as flaccid and those with more tone than normal are described as spastic. Muscle tone tonic contraction is maintained by negative feedback mechanisms centered in the spinal cord. Slow Phasic Red Fibers These fibers contain a high content of myoglobin, an oxygencarrying pigment in muscle.
Slow fibers have thick myofilaments made of a type of myosin that reacts at a slow rate.
Due to their slow contraction, the fibers are able to produce adenosine triphosphate ATP quickly enough to meet the energy demands of myosin and avoid fatigue.
This is enhanced by the high density of mitochondria and capillaries, and also the high content of myoglobin. There is a complete breakdown of glucose to carbon dioxide, water, and energy in slow fibers.
Slow fibers are suited for contractions seen in postural muscles.
Due to their rapid rate of contraction, ATP is depleted rapidly. Fast fibers rely on anaerobic respiration to regenerate ATP due to their low content of mitochondria, though the fibers are rich in glycogen.
During anaerobic respiration, a glucose molecule is broken down into two pyruvic acid molecules.
In the presence of oxygen, pyruvic acid is converted to acetyl-CoA which enters the citric acid cycle in the mitochondria and transfers chemical energy to the maximum number of ATP molecules via oxidative phosphorylation. In most human cells, one glucose molecule produces enough usable chemical energy to synthesize 36 ATP molecules. If oxygen is not available, pyruvic acid is converted to lactic acid, incurring an oxygen debt.
The oxygen debt is later repaid when ATP produced via oxidative phosphorylation is used to convert lactic acid back to pyruvic acid or even all the way back to glucose.
As a result, fast fibers cannot sustain a contraction for long. Glycolysis takes place in the sarcoplasm of muscle fibers whereas the citric acid cycle occurs in their mitochondria. Intermediate Phasic Pink Fibers Intermediate fibers have characteristics between those of fast and slow fibers.
Questions for the bell-ringer section will ask you to identify labeled structures on dissected animals, skeletons, and tissue slides within a time limit. The goal of a "bell-ringer" lab exam is to test your ability to identify those structures that you learned in lab and your understanding of their form and function based upon your observations of materials in front of you. Each lab practical exam is scheduled during a regular lab period. Important Notes - The second lab practical exam will not be comprehensive and will include only material learned since the first lab exam.
This room will not be available during this week outside of our scheduled lab periods. Lab Quizzes: You are not required to write the lab quizzes. A separate handout has been prepared to discuss the essay. A late penalty of 0. Dilkes of your absence before the start of the lecture exam or your regular scheduled lab period.
Any student who does not do so may forfeit the chance to write a makeup exam or quiz and a grade of zero will be assigned.
It is the student's responsibility to contact Dr. A message from a family member or friend is not acceptable. Contact may be an email, message on my office answering machine, or a message to the Biology Office HS; phone: Documentation is Required for All Makeup Exams and Quizzes Any absence from a lecture exam, lab exam, or quiz must be supported by documentation. Makeup Lecture Exams Students who miss a lecture exam see Acceptable Reasons for Absences below are offered a make-up so long as documentation is provided.
If you miss the makeup exam on the scheduled date and provide documentation, alternate arrangements for a makeup will be made or an incomplete recorded. Without documentation, a grade of zero will be recorded. Makeup Lab Quizzes If you expect to miss your regular lab, then it is your responsibility to inform Dr.
Dilkes of your absence and discuss any possible arrangements to write missed quizzes at a later date. This is particularly true for the Crocodylia because they display a diversity of postures and gaits, from belly-sliding through to galloping [ 1 — 3 ], Consequently, anatomical and functional analyses of crocodilian musculature and locomotion have been widely used in muscle reconstructions of dinosaurs [ 4 — 16 ].
The locomotor variety apparent in both living and extinct members of the Crocodylia has promoted discussions on changes in musculoskeletal architecture of these clades [ 1 , 17 — 22 ]. To date, research into the appendicular morphology of Crocodylia has largely focused on the American alligator Alligator mississippiensis.
Many studies describe the limb anatomy of A. In addition, kinematic studies have also been undertaken on the forelimb of A. Currently no appendicular anatomical studies exist for Crocodylus porosus Schneider, and only a single study exists on the limb functional morphology of this species [ 30 ].
Conducting a digital dissection is a non-destructive method that allows users to interact with data in three-dimensions. This gives researchers the ability to better visualise different muscles and identify their anatomical position. It further complements existing two-dimensional illustrations which are often simplified or stylised and hence open to misinterpretation [ 31 — 33 ].
Additionally, conducting a dissection digitally means anatomical features can be confirmed and re-examined [ 34 ]. Published digital dissections have been conducted on a variety of vertebrate taxa, largely focusing on cranial musculature [ 31 , 32 , 34 — 39 ], with a single paper using this technique to study pes myology in elephants [ 40 ].
Utilising computed tomography data CT; predominately microCT is the most common method used for digital dissections [ 34 , 38 , 39 , 41 ]. However, often CT does not provide enough soft tissue detail to conduct an adequate digital dissection [ 34 ].