Muscle Anatomy and Function Quiz

Skeletal System: The Skull

• The skeleton is divided into exoskeletons and endoskeletons.
• Exoskeletons are located within the integument and can be keratinized (from epidermis) or bony (from dermis).
• Endoskeletons are deep within the body and can be bony or cartilaginous.
• The cranial skeleton includes the chondrocranium and splanchnocranium and dermatocranium.
• The postcranial skeleton includes the axial skeleton and the appendicular skeleton
• The postcranial skeleton includes vertebral column, notochord, limbs, girdle

3 Subdivisions of the Skull

• Chondrocranium,
• Splanchnocranium,
• Dermatocranium

Structures of the Skull

• The diagram shows various parts of the skull, like supra-branchials, epibranchials, hyomandibula, sympletic, quadrate, ceratohyal, articular, palatoquadrate, palatine, etc
• The diagram demonstrates how different components of the skull develop through different evolutionary stages
• The diagrams show how the different structures of the Skull change during various developments
• Detailed diagrams of the skull from different ages

Late Devonian Lobe-Finned Fish and Amphibious Tetrapods

• The diagram shows different species of fish and amphibians that lived during the Late Devonian period.
• These animals show different adaptations to the environment (e.g., freshwater, land, etc.)
• These adaptations are crucial steps in the evolution of tetrapods.
• The diagram shows the evolutionary change from early tetrapods (aquatic) to land dwelling tetrapods

Endochondral Contributions to the Chondrocranium

• Table showing contributions of endochondral bones to the chondrocranium in different vertebrate classes (fishes, amphibians, reptiles/birds, mammals).
• Lists occipital bones, mesethmoid bone, ethmoid region, sphenoid bones, laterosphenoid, otic capsule, and perotic structures
• Data on the table demonstrates the evolutionary changes in the structure of endochondral bones and the specific endochondral contributions in those structures

Major Dermal Bones of the Skull

• Table showing major dermal bones of the skull, categorized into facial, orbital, temporal, vault, palatal, and mandibular series
• Includes the premaxilla, maxilla, nasals, lacrimal, prefrontal, postfrontal, postorbital, and jugal bones in facial series; and the intertemporal, supratemporal, tabular, squamosal and quadratojugal in temporal series
• Also includes vomer, palatine, ectopterygoid, pterygoid, parasphenoid, and coronoids
• Provides a comprehensive list of dermal bones in different areas of the skull
• The table lists the dermal bones in the skull in different series

Skull of a Chick & Human Fetus

• The diagrams show the bones or portions of bones that are developed from neural crest cells (shaded).
• The table gives acronyms for each specific bone to understand the exact parts.

Visceral Arches in Sharks, Teleosts, and Tetrapods

• Table showing the derivatives of branchial arches in sharks, teleosts, amphibians, reptiles/birds, and mammals.
• Details the various structures derived from different branchial arches with the different groupings
• Includes Meckel's cartilage, palatoquadrate, and hyomandibula and detailed structural representation across various groups of animals
• Provides comparative information across various groups of organisms

Types of Skull and Jaw Suspension

• Diagram of the different types of skull and jaw suspension in various vertebrate groups

Skull and Visceral Skeleton

• Two functionally independent cartilaginous components are derived from replacement bones (neurocranium & splanchnocranium).
• Provides a basic understanding of the skull and visceral skeleton

Neurocranium

• Protects the brain and anterior part of the spinal cord.
• Has sense organ capsules and is an embryonic adaptation
• Has four ossification centers

Sphenoid Region

• The sphenoid region consists of basisphenoid, presphenoid, and orbital and laterosphenoids
• These fuse to form a single bone in mammals

Temporal, Ethmoid & Otic regions

• Ethmoid region is anterior to the sphenoid,
• Cribriform plate and olfactory foramina
• Otic region has three bones in tetrapods (prootic, opisthotic and epiotic) which unite in birds and mammals to create the petrosal bone.

Visceral Skeleton

• Also known as the branchial region; it has different subdivisions/regions

Visceral-Cranial Derivatives

• Derived from skeletal elements from different pharyngeal arches

Dermatocranium

• Formed by membrane bone, not replacement bone.
• Has dermal bones of the skull such as the nasal bone, squamous bone, palate and mandible.

Neurocranial Elements

• The elements of the neurocranium include, cribriform, ethmoid, otic complex and temporal bone

Splanchnocranial Elements

• Contains elements including the malleus, incus and stapes and the styloid process of the hyoid
• Structures are derived from visceral arches

Visceral Arches of Man

• The visceral arches of man include the styloid processes, body of the hyoid, thyroid and cricoid structures

Middle Ear Bones

• Includes the malleus (hammer), incus (anvil), and stapes (stirrup).

Appendicular Skeleton

• Pectoral Girdle
• Pelvic Girdle
• Appendages
• Adaptations for speed

Pectoral Girdle

• Has two sets of elements, cartilage or replacement bone, and membrane bone.
• Replacement bones include coracoid, scapula, suprascapula
• Membrane bones include clavicle, and cleithrum, supracleithrum .
• Reduction in bones over evolution

Pelvic Girdle

• No dermal elements.
• Three replacement bones (ilium, ischium, pubis)
• Triradiate pelvic girdle (alligators and dinosaurs)

Appendages

• Single unit in both fore and hind limb most medial
• Two units in fore and hind limb distal area

Ribs

• Dogfish develops dorsal ribs.
• Most teleosts develop ventral ribs.
• Tetrapods have both dorsal and ventral ribs.
• Dorsal ribs are lost; proximal rib heads enlarge.
• Two rib portions articulate with vertebrae (tuberculum and capitulum).
• Agnathans have no ribs.
• Amphibians' ribs never reach the sternum.
• Birds have flat processes extending off ribs posteriorly (unicate processes).

Adaptations for Speed

• Plantigrade (flat on the ground; primates),
• Digitigrade (elevated; carnivores),
• Unguligrade (reduction in digits; two types
• Perissodactyls, odd-toed ungulates with weight on enlarged middle digit (e.g., horse)
• Artiodactyls, even-toed ungulates with weight equally distributed on the 3rd and 4th digits(e.g., camel).

Locomotion Without Limbs

• Serpentine (lateral undulation, wave motion, minimum 3 contact points)
• Rectilinear (straight line, scutes on belly lift, costocutaneous muscles)
• Sidewinding (minimum 2 contact points, adaptation to sandy habitats)
• Concertina (minimum 2 contact points, allows snakes to move upward in a gutter)

Heterotopic Bone

• Develops by endochondral or intramembranous ossification.
• In areas subject to continual stress
• examples of Os cordis, rostral bone, os penis, os clitoridis, falciform, sesamoid, patella and pisiform

Skull and Visceral Skeleton

• Two functionally independent components (neurocranium and visceral skeleton) derived from replacement bones:

Cranial/Sphenoid/Temporal/Ethmoid/Otic/Visceral Skeletal Elements

• Detailed breakdown of various skull components, particularly for mammals and including related structures like the visceral arches

Muscle origins and Naming

• Somites are the source of somatic muscles (including the limbs).
• Lateral plate mesoderm - provides somatic muscles in the flank.
• Splanchnic mesoderm - contributes to visceral muscles

Vertebrae Grouping

• Grouped based on body region (cervical, thoracic, lumbar, sacral, caudal).
• Amphibians are the first vertebrates to possess cervical vertebrae.

Reptile Vertebrae

• Atlas as the 1st cervical and axis as the 2nd.
• Turtle: 8 cervicals, 2 sacrals, 10 dorsals, 16-30 caudals
• Alligator: 8 cervicals, 11 thoracic, 5 lumbar, 2 sacrals, up to 40 caudals

Bird Vertebrae

• Possess atlas and axis
• 13-14 free cervicals, 4 fused thoracics, fused synsacrum, free caudals, pygostyle

Mammal Vertebrae

• Most have 7 cervicals
• 12 thoracic and 5 lumbar compose dorsal vertebrae
• Ancestral mammals had ~27 presacrals
• Sacrum is 2-5 fused vertebrae
• Caudals are variable
• Primates have 2-5 fused into coccyx

Vertebra Evolution

• Transition from crossopterygians to labyrinthodonts,
• Different types of vertebrae derive from primitive rachitomatous labyrinthodonts
• Two pleurocentra & U-shaped hypocentrum
• Hypocentrum is lost and pleurocentrum enlarges and forms centrum in modern amniotes

Phylogenic Groups

• Categorizations of various groups and subtypes that exist based on the different anatomical features and adaptations observed

Appendicular Skeleton/Axial Skeleton

• Comprehensive description of the skeletal system/subsystem

Vertebrae

• Types of centra (e.g., amphicoelous, opisthocelous, procelous, acelous)
• Evolution of centra (e.g., pleurocentra, hypocentrum).
• Grouping of vertebrae according to body region (e.g., cervical, thoracic, lumbar, sacral, caudal).

Locomotion Without Limbs & Adaptations for Speed

• Discussions on different adaptation strategies for movement without limbs (serpentine, rectilinear, sidewinding, concertina)
• Different adaptations for speed in different animal groups (plantigrade, digitigrade, unguligrade).

Digestive Tract

• Subdivisions of vertebrate digestive tracts (mouth, pharynx, esophagus, stomach, small intestine, large intestine, and cloaca).
• Differences in digestive tracts related to diet (e.g., herbivores, carnivores).

Respiratory System

• Adaptations like gills, lungs, cutaneous respiration & breathing mechanisms, for various taxa
• Modification details for each taxa discussed

Urogenital System

• Embryological origins & general functions including urine excretion and osmoregulation and the merging of urinary and reproductive processes
• Development of vertebrate kidneys (pronephros, mesonephros, metanephros)
• Details of blood supply and structures

Circulatory System

• General description of vertebrate circulatory systems that include the heart, arteries, capillaries, veins and blood flow patterns among various taxa.
• Modifications to the circulatory systems in different vertebrates (lungfish, amphibians, reptiles, and mammals)
• Details on the circulatory functions, modifications and adaptations for each group.

Lymphatic System

• Description and function details on lymph vessels, lymph nodes and lymph hearts.