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PHYLUM CHORDATA 5 CHORDATE HALLMARKS, SUBPHYLUM CEPHALOCHORDATA,…

- - - - Water passes through
  - - - Opening at the
        atrium's posterior
- - - - Water inlet
    - - Water outlet
  - - - From the epidermis
      - Made of proteins, salts, cellulose
- - - - Chemical and mechanical
        stimuli detection
  - - - Continuous digestive tract
    - - Cilias within stigmas
        allow water water to pass through the pharynx, into the atrium, and out the atrial siphon
      - Slits w/in the pharynx
- - - - Near the atrial siphon
  - - - External Fertilization
- - - - Larva undergoes metamorphosis after finding a suitable substrate
        
        Adhesive structures
        located within the mouth
        
        Surface coverings shrink, compressing the notochord and tail for reorganization
        
        Internal structures rotate 180 degrees, reorienting the siphons away from the substrate
        
        Digestive system bends and
        forms the characteristic U shape
- - - - Vertebral Column
        
        COMPONENTS
        
        Cartilage
        
        Bone
        
        MAJOR LANDMARKS
        
        Centrum
        
        encloses notochord
        
        Neural Arch
        
        encloses spinal cord
        
        Neural Spines
        
        Hemal Arch
        
        encloses blood vessels
        
        Hemal Spines
        
        Vertebrae
      - Cranium
        
        COMPONENTS
        
        Cartilage
        
        Bone
  - - - AGNATHAN
        
        Hagfish
        
        Deposit/Scavenger Feeding
        
        knotting behavior
        
        Lamprey
        
        Parasitic Feeding
        
        jawless fishes
        
        Feeding: Muscular Pump
        
        modifications in oral cavity (e.g., teeth in tongue)
        
        more active feeding lifestyle (deposit feeding, thicker fluid consumption, feeding on dead animals)
      - GNATHOSTOMES
        
        Expanded Anterior Pharyngeal/Mandibular Arch
        
        led to
        
        Jaws
        
        allowed opening/closing of oral cavity; biting
        
        Feeding: Raptorial
        
        jawed vertebrates
      - PREVERTEBRATES
        
        Feeding: Filter-feeding (Cilia)
        
        produced a
        
        Muscular Pump
        
        led to
        
        Gills
        
        COMPONENTS
        
        Muscular Pharynx
        
        Cartilaginous Pharyngeal/Gill Bars
        
        Arose from protochordates
- - - - DERMIS
        
        BASEMENT MEMBRANE
        
        EPIDERMIS
        
        from ECTODERM
        
        specialized structures
        (e.g., hair, feathers)
        
        GENERAL SUBLAYERS
        
        STRATUM CORNEUM
        
        STRATUM BASALE
        
        BASAL LAMINA
        
        RETICULAR LAMINA
        
        from ECTODERM & MESODERM
        
        INTRAMEMBRANEOUS
        OSSIFICATION
        
        some produce
        
        DERMAL BONES
        
        from MESODERM
        
        COLLAGEN
        
        skin stretchability is
        confined to dermis
      - "SUPERFICIAL FASCIA"
      - Fat and Blood Vessels
  - - - EPIDERMIS
        
        EPIDERMAL CELLS
        
        produces secretory vesicles that contribute to mucus cuticle
        
        UNICELLULAR GLANDS
        
        CLUB CELLS
        
        excitement/fear responses
        
        GRANULAR CELLS
        
        GOBLET CELLS
        
        mucus production
        
        SACCIFORM CELLS
        
        predator repellant
      - DERMIS
        
        COLLAGEN
        
        STRATUM COMPACTUM
        
        layer of compact collagen
        
        arranged in PLIES
        
        SHARKS
        
        collagen fibers lie at angles
        
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        WARP & WEFT ARRANGEMENT
    - - CHONDRICHTHYES
        (CARTILAGINOUS FISH)
        
        PLACOID SCALE
        
        Dermis: Dentin
        
        Epidermis: Enamel
        
        Pulp Cavity
        
        continuous with dermis
      - OSTEICHTHYES
        (BONY FISH)
        
        GANOID SCALE
        
        Enamel + Double ➡️ Single Bone
        
        Gars
        
        TELEOST SCALE
        
        Bone (Lamellar)
        
        CYCLOID SCALES
        
        Posterior end: Smooth edges
        
        Tilapia
        
        CTENOID SCALES
        
        contain
        
        Circuli
        
        Posterior end: Spiny projects
        
        COSMOID SCALE
        
        Dentin + Enamel + Double Bone
        
        Coelacanths
  - - - EPIDERMIS
      - DERMIS
        
        COLLAGEN
        
        irregular collagen
        arrangement
        
        stratum compactum
        in amphibians
        
        MULTICELLULAR GLANDS
    - - different levels across different classes
    - - EPIDERMIS
        
        LAYERS
        
        STRATUM GRANULOSUM
        
        STRATUM CORNEUM
        (outermost)
        
        STRATUM BASALE
        (innermost "base")
        
        MOLTING/ECDYSIS
        
        Stratum basale produces new stratum corneum and granulosum;
        pushes away older layers
        
        STRATUM INTERMEDIUM
        
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        EPIDERMAL SCALES
        
        SCUTES
        
        large epidermal scales arranged as plates
      - DERMIS
        
        DERMAL BONES
        
        OSTEODERMS
        
        dermal bones w/c support the epidermis + its scales
        
        crocodiles, turtles
        
        GASTRALIA
        
        abdominal bones w/c also have dermal origins
    - - EPIDERMIS
        
        LAYERS
        
        STRATUM BASALE
        (innermost "base")
        
        STRATUM GRANULOSUM
        
        STRATUM CORNEUM
        (outermost)
        
        STRATUM LUCIDUM
        
        STRATUM SPINOSUM
        
        CELLS
        
        KERATINOCYTES
        
        major cellular components
        
        CALLOUSES
        
        abnormal thickening of
        
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        originate from
        
        MELANOCYTES
        
        pigmentation (melanin)
        
        ALBINISM
        
        melanocytes not producing enough melanin
        
        LANGERHANS CELL
        (INTRAEPIDERMAL MACROPHAGES)
        
        protection against microorganisms
        
        MERKEL CELL
        (TACTILE EPITHELIAL CELL)
        
        sensory function
        
        Epithelial Tissue
      - DERMIS
        
        Connective Tissue
        
        FIBROBLASTS
        
        COLLAGEN & ELASTIC FIBERS
        
        WRINKLES
        
        due to slowing of collagen & elastic fiber synthesis
        
        STRIAE
        
        when skin is stretched too much:
        internal scarring at dermis level
        
        SPECIALIZED NERVE ENDINGS
        
        Pressure
        
        Fine Touch
        
        Pain
        
        Itching
        
        Temperature
      - ACCESSORY ORGANS
        
        HAIR
        
        HAIR ANATOMY
        
        SHAFT
        
        superficial portion above skin
        
        ROOT
        
        HAIR BULB
        
        deepest root portion
        
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        DERMAL PAPILLA
        
        contains BVs that provide nutrients; free nerve endings (sensory function)
        
        ARRECTOR PILI MUSCLE
        
        adjacent smooth muscle that erects hair in the cold (e.g., goosebumps)
        
        CROSS SECTION
        
        CUTICLE (outermost)
        
        CORTEX (middle)
        
        MEDULLA (innermost)
        
        HAIR FUNCTIONS
        
        SCALP HAIR
        
        reduces injuries & provides insulation
        
        EYE BROWS,
        EYELASHES
        
        protects eyes from foreign material/debris
        
        NOSE HAIRS
        (VIBRISSAE)
        
        protects nose from foreign material
        
        AXILLARY & PUBIC
        HAIR
        
        reduces friction
        
        HAIR ROOT PLEXUS
        
        sensory structures (e.g., feeling the wind)
        
        DEAD, keratinized EPITHELIAL cells held together by proteins
        
        NAILS
        
        Plates of tightly packed, hard, DEAD KERATINIZED cells that cover the dorsal surface of the distal portion of digits
        
        NAIL ANATOMY
        
        FREE EDGE
        
        extends past distal digit end, white due to absence of capillaries
        
        NAIL ROOT
        
        buried under skin think: root is hidden
        
        LUNULE
        
        white 🌒-shaped at proximal nail plate end
        
        EPONYCHIUM
        (CUTICLE)
        
        narrow epidermis band that adheres to proximal nail plate end
        
        HYPONYCHIUM
        
        stratum corneum portion beneath free edge; secures nail to fingertip
        
        NAIL PLATE
        
        visible portion, pink due to dermis BVs
        
        GLANDS
        
        SEBACEOUS
        
        lipids; oily secretion
        
        location: dermis
        
        released towards stratum corneum
        
        ACNE VULGARIS
        
        inflamed sebaceous gland
        
        ECCRINE
        
        thin watery fluids (ETHIN)
        
        ECCRINE SWEAT GLANDS
        
        thermoregulatory sweating
        
        emotional sweating
        
        APOCRINE
        
        thick, lipid-containing fluid
        
        associated w/ hair follicles
        
        APOCRINE SWEAT GLANDS
        
        associated w/ body odor
        
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        SCENT GLANDS
        
        chemical signaling & social communication
        
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        MAMMARY GLANDS
        
        produce MILK
        
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        number varies across species
        
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    - - DERMIS
        
        MUCUS GLANDS
        
        POISON (GRANULAR) GLANDS
        
        Frogs: Aposematic Coloration
      - EPIDERMIS
        
        LEYDIG CELLS
        
        anti-bacterial & anti-viral
        disappears in adult form
        
        Salamander Larvae
        
        NUPTIAL PADS
        
        mating: male frog to cling to female
        
        Frog
    - - EPIDERMIS
        
        LAYERS
        
        STRATUM BASALE
        (innermost "base")
        
        STRATUM CORNEUM
        (outermost)
        
        STRATUM INTERMEDIUM
        
        soon keratinizes and forms part of
        
        FEATHERS
        
        PARTS
        
        SPATHE
        
        RACHIS
        
        central tubular shaft
        
        VANE
        
        gets shape from
        
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        CALAMUS/QUILL
        
        anchors feather to body
        
        TYPES
        
        CONTOUR FEATHER
        
        gives shape & streamlines; aerodynamic
        
        FLIGHT FEATHER
        
        contour feather seen on wings for locomotion
        
        DOWN FEATHER
        
        insulation
        
        FILOPLUME
        
        display only
        
        TAIL FEATHER
        
        balance
        
        LOCATION
        
        PTERYLAE
        (feather tracts)
        
        APTERIA
        (non-feathered tracts)
      - DERMIS
        
        highly vascularized
        
        BROOD PATCH
        
        increases vascularity for egg incubation
        
        GLANDS
        
        UROPYGIAL GLAND
        
        lipid/protein substance for preening
        (feather conditioning)
        
        SALT GLAND
        
        excrete excess salt
- - - - Somatic Muscles
        
        bone/cartilage movement
      - Visceral Muscles
        
        seen alongside organs
    - - Voluntary Muscles
        
        conscious control
      - Involuntary Muscles
        
        not conscious
    - - Skeletal
        
        voluntary
        
        striated
        
        Skeletal Muscle Cell
        
        MYOFIBRILS
        
        SARCOMERE
        
        Z-Disc: separates sarcomeres, anchors ACTIN
        
        H-Zone: only MYOSIN (A-BAND)
        
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        alternating ACTIN & MYOSIN filaments
        
        NERVE CELL
        
        forms motor end plate upon contact w/ sarcolemma
        
        Motor End Plate
        
        Transerve/t-tubules
        
        carry electrical impulses from nerve cvell to muscle cell
        
        multinucleated
        
        connective tissue coverings
        
        fascial
        
        groups/compartmentalize muscles
        
        epimysium
        
        outer covering; dense irregular
        
        perimysium
        
        covers fascicles (smaller muscles)
        
        endomysium
        
        covers individual muscles
      - Smooth
        
        involuntary
        
        non-striated
        
        function: peristalsis, vasoconstriction, vasodilation
      - Cardiac
        
        involuntary
        
        striated
        
        mononucleate or binucleate
        
        function: contractile heart movements
        
        Cardiac Cells
        
        Intercalated Disks
        
        connect cardiac muscle cells to e/a
        
        branching fibers
    - - Red Muscle
        
        high vascularization
        
        high myoglobin and mitochondria
        
        endurance
      - White Muscle
        
        low vascularization
        
        low myoglobin
        
        speed
    - - Tonic Muscle
        
        slow, sustained contractions
        
        amphibians/reptiles: posture & musculature
        
        basking turtle
        
        others: rarely observed
        
        extrinsic eye/middle ear muscles
      - Twitch Muscle
        
        Classifications
        
        Fast Twitch
        
        Fast twitch, fatigue-resistant (FR)
        
        weaker, sustained contractions
        
        walking, swimming
        
        Fast twitch, fatiguable (FF)
        
        strong, fast contractions
        
        powerful bursts (e.g., punching)
        
        Slow Twitch (S Fibers)
        
        fatigue-resistant
        
        posture, aerobic endurance exercise
        
        marathon runners
        
        coexist w/in a muscle
        
        Order of Recruitment: S, FR, SS
        
        fast, rapid contractions
        
        all vertebrates
  - - - connective tissue forms cord-like structure in bone attachment
    - - tendinous structures that flatten out & attach through connective tissue sheets
      - head (epicranial aponeurosis), palms (palmar aponeurosis), soles of feed (plantar aponeurosis)
  - - - primary action of muscle
    - - Flexion
        
        Extension
        
        Abduction
        
        Adduction
        
        Pronation
        
        Supination
        
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        palm facing down
        
        movement towards midline
        
        movement away from midline
        
        straightens joint
        
        bends joint
    - - Synergists
        
        muscles act together to produce movement in same direction
      - Antagonists
        
        muscles that produce opposing motions
    - - fixed point of attachment
    - - movable point of attachment
- - - - CARTILAGE ECM
        
        CHONDROITIN SULFATE
        
        COLLAGEN & ELASTIC FIBERS
        
        CELLS
        
        CHONDROCYTES
        
        housed w/in LACUNAE
      - Types
        
        Hyaline
        
        Most common
        
        Framework for bone formation
        
        ELASTIC & COLLAGEN FIBERS
        
        LOCATION: on articular surface, rib tips, tracheal cartilage, parts of the skull
        
        Elastic
        
        Flexible and springy due to elastic fibers in the ECM
        
        LOCATION: EE (Ear and Epiglottis)
        
        Elastic Fibers
        
        Fibrocartilage
        
        Resistant to tensile and warping forces
        due to collagen reinforcements
        
        LOCATION: weight-bearing & bending body regions (intervertebral discs, symphysis pubis, and the knee meniscus)
        
        Collagen Fibers
      - AVASCULAR: No blood or nerve supply
        
        Blood vessels confined
        to the perichondrium
      - flexible yet
        firm connective tissue
    - - BONE ECM
        
        CELLS
        
        OSTEOCYTES
        
        OSTEOCLASTS
        
        bone reabsorption
        
        OSTEOBLASTS
        
        become osteocytes in bone matrix
        
        housed w/in LACUNAE
        
        CALCIUM PHOSPHATE
      - CLASSIFICATIONS
        
        Organization
        
        Lamellar
        
        Organized
        collar fibers
        
        Lamella
        
        Bone matrix + closely
        packed collagen fibers
        
        Stronger than woven bone
        
        Non-lamellar (woven)
        
        fast-growing
        
        irregularly arranged
        collagen fibers
        
        Used in bone creation
        and fracture healing
        
        Matures to become
        lamellar bone
        
        Location
        
        Cortical Bone
        
        forms cortex (outer boundary)
        
        Medullary Bone
        
        Bone core; filled
        with bone marrow
        
        Appearance
        
        Compact bone
        
        Osteonic Canal
        
        Lacuna
        
        dark spaces w/in lamellae
        
        Canaliculi
        
        small spaces from lacuna
        
        forms OSTEONS
        
        dense and solid
        
        Cancellous (spongy) bone
        
        Trabeculae
        bony structures
        
        Bone marrow
        fills the spaces
        
        porous w/ spaces in between
        
        Embryonic
        development
        
        Intramembranous
        
        Arises from dermal bones
        (e.g., skull, pectoral girdle)
        
        Forms
        
        Dermal
        
        Derived from the mesenchyme
        
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        Perichondral & Periosteal Bone
        
        Derived from fibrous
        connective tissues
        
        increase bone
        girth; fracture repair
        
        Sesamoid bone
        
        Embedded within
        connective tissue
        
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        Endochondral
        More common; arises
        from cartilaginous frameworks (HYALINE)
        
        Ex: Keel Bone
        
        Observed in chicken breasts
        
        Attachment point for
        flight muscles
        
        Has cartilage in
        posterior portion
        
        Young ones: Not completely ossified
        
        Regions of Long Bones
        
        Diaphysis
        Middle shaft
        
        primary ossification center
        
        Metaphysis
        Between epiphysis and diaphysis
        
        Epiphyseal line
        (adults)
        
        Epiphyseal plate
        (children)
        
        Made of cartilage and growing
        
        from Hyaline Cartilage
        
        Epiphysis
        (Ends)
        
        secondary ossification center
        
        Lines of arrested growth
        
        Indicates period of stress
        
        interruption in bone growth
        
        Joints
        
        Diarthrosis (Synovial Joints)
        Permits movement
        
        Components
        
        Synovial capsule
        
        dense fibrous
        tissue cover
        
        Synovial membrane
        
        produces the lubricant
        synovial fluid
        
        Articular cartilage
        
        Has hyaline and observed on
        
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        Synarthrosis (Restrictive Joints)
        No movement
        
        Classifications based
        on structures joined
        
        Synostosis
        Bone-bone
        
        Synchondrosis
        Bone-Cartilage-Bone
        
        Syndesmosis
        Connective tissue
      - connective tissue where calcium phosphate is deposited within the ECM
      - VASCULAR
  - - - Splanchocranium
        (Viscerocranium)
        
        Most ancient; initially
        appeared as part of the
        anterior pharyngeal arches
        
        Structures
        
        Mandibular arch
        
        Palatoquadrate
        (Dorsal)
        
        Gave rise to derivatives
        (e.g., ear bones)
        
        AUDITORY OSSICLES (MIDDLE EAR BONES)
        
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        Meckel's cartilage
        (Ventral)
        
        Enclosed by the
        dermatocranium
        
        Cartilage disappears
        in some vertebrates
        
        Hyoid Bone
        
        Ventral aspect of splanchnocranium
        
        Fish & Amphibans: Forms the mouth floor
        
        Humans: Attachment for the tongue
        and neck muscles
      - Chrondrocranium
        (Neurocranum)
        
        Directly beneath
        the brain
        
        Component: edochondral
        bone/cartilage
        
        Capsules
        
        Nasal, optic, and otic capsules form occipital, ethmoid, and basal
        
        Humans: Occipital, ethmoid,
        and sphenoid bones
        
        Foramina
        
        openings where cranial nerves & BV pass through
      - Dermatocranium
        
        Made up of dermal bones and
        developed from integument
        
        Makes up most of the
        outer casing of the skull
        
        Parts
        
        Facial Series
        
        Surrounds the nares
        and forms the snout
        
        Recall: Brachocephalic/Oligocephalic Dogs
        
        Maxilla and premaxilla forms most of the upper jaw and bear teeth
        
        Nasal bone at the anteromedial aspect
        
        Orbital Series
        
        Surrounds the orbit
        and the eyes
        
        Lacrimal (openings
        for the nasolacrimal duct, in eye socket)
        
        Zygomatic bone
        (cheekbones)
        
        Eye Positioning and
        Depth Perception
        
        Predators: Binocular vision
        front-facing eyes
        better depth perception
        
        Prey: Monocular vision
        lateral eyes
        wider field of view
        
        Vault Series
        
        Roofing bones run atop the
        skull, covering the brain
        
        Humans: Frontal and parietal
        bone (calvaria)
        
        Sutures: Wavy fixed joins
        
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        Glabella
        
        border between superior border of left & right orbit
        
        Temporal Series
        
        Attachment point
        for jaw muscles
        
        area: braincase posterior wall
        
        External Acoustic Meatus
        
        opening of ear (~ear canal); point of attachment to jaw muscles
        
        Palatal Series
        
        Covers the roof
        of the mouth
        
        Pterygoid and parasphenoid bones
        
        Pterygoid is reduced in mammals
        
        Cleft Lip and Palate
        
        Result of incomplete fusion of
        the palate during pregnancy
        
        Mandibular Series
        
        Consists of the dermal bones
        that will surround Meckel's cartilage (Splanchnocranium)
        
        MANDIBLE
        
        incomplete fusion results in
        
        Cleft chin
        
        Derivative bony structures (e.g., teeth)
  - - - Distal - modifications
        related to lifestyle
      - Proximal - attached
        to the body
      - Components
        
        Paired Limbs or Fins
        
        supported by
        
        Girdles
        
        Shoulder or pectoral
        girdle (anterior)
        
        Sacral region
        
        Dermal or
        endochondral origin
        
        Ilium: point of attachment between pelvic & pectoral girdle
        
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        Hip or pelvic girdle
        
        Endochondral origin
        
        Later Vertebrates:
        
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        Aquatic
        
        Fins
        
        Fin Rays Classification
        
        Lepidotrichia
        bony fish
        
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        Ceratotrichia
        elasmobranchs
        
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        Paired: Pectoral, Pelvic
        (PPP)
        
        Pectoral
        
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        Pelvic
        
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        Single: Caudal, Dorsal
        Anal Fins
        
        Caudal
        
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        Dorsal and anal fins
        
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        Terrestrial
        
        Limbs (Chiridia)
        
        Tetrapod: 3 regions
        
        Zeugopodium (Middle)
        
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        Autopodium (Distal)
        
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        Stylopodium (Proximal)
        
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        Origins
        
        Paired fish fins
        (pectoral + pelvic)
        
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  - - - Made of fibrous connective tissue
        wrapped around fluid-filled cells
      - Flexible yet rigid
    - - Series of repeating segments of
        bony or cartilaginous elements
      - Functions
        
        Originally protect the spinal
        cord and dorsal aorta
        
        Site for muscle attachment
        
        For vertebrates: Support the body and facilitate land movement
      - Surpassed the notochord as
        the primary support structure
      - Vertebral arches
        
        First to appear
        
        Rests on the notochord
        
        Neural arch (dorsal):
        Protects the neural tube
        
        Hemal arch (ventral):
        protect blood vessels
      - Centrum
        
        Initially appeared as separate structures that expand to surround the notochord
        
        Varies according to extent of
        ossification and degree to which the notochord has been replaced
        
        Pleurocentrum - lateral notochord
        
        Body of the vertebra
        
        Intercentrum - ventral notochord
        
        Intervertebral cartilage or discs
        
        nucleus pulposus
      - Vertebrae
        
        Each vertebral segment consists
        of the following elements:
        
        1-2 dorsal arches (neural
        and interneural)
        
        Centrum
        
        1-2 ventral arches (hemal
        and interhemal)
        
        Anatomy
        
        Centrum/Body
        
        Mechanical element
        
        Transverse process
        
        Emanate from the
        sides of the centrum
        
        Apophysis
        
        Articular surfaces used
        as attachment points
      - Regionalization
        
        Bony Fish
        
        2 REGIONS: Caudal, Trunk
        
        Early tetrapods
        
        4 REGIONS: Caudal, Sacral, Trunk, Cervical
        
        Primitive Amniote
        
        4 REGIONS: Caudal, Sacral, Thoracolumbar, Cervical
        
        Early mammals
        
        5 REGIONS: Caudal, Sacral, Lumbar, Thorax, Cervical
    - - Muscle attachments
      - Rigidity for movement
      - Stop telescoping
      - Support against gravity
      - Support breathing
    - - Bones that prevent
        visceral compression
      - Muscle attachment
      - Accessory breathing organ
        
        rib flexibility from hyaline cartilage
      - Types
        
        True Ribs
        
        Ventral articulation
        with the sternum
        
        False Ribs
        
        Articulate only
        to each other
        
        Floating Ribs
        
        No ventral articulation
        
        determined by articulation to sternum
      - articulate with thoracic vertebra
    - - Midventral skeletal structure
      - Articulates with shoulder girdle
      - Attached to chest muscles
    - - "Abdominal ribs"
      - Dermal origin
      - No articulation with vertebrae
      - Posterior to the sternum
      - Confined to the ventral side of the body
- - - - mechanical & chemical digestion begin
      - bolus
        
        swallowed food
        
        swallowing = "deglutition"
      - dentition
        
        herbivores (prominent diastema)
        
        diastema
        
        space between incisors/canines and molars
        
        carnivores (prominent incisors & canines)
    - - passageway that leads to trachea & esophagus
        
        Epiglottis
        
        directs bolus towards
        
        elastic cartilage
    - - Foregut
        
        Stomach
        
        Glandular Epithelium
        
        Cardia
        
        glands for mucus
        
        Fundus
        
        specialized glands for chemical digestion
        
        Pylorus
        
        glands for mucus, neutralizes acids in chyme before entrance to intestine
        
        Non-Glandular Epithelium
        
        Gizzard
        
        mechanical digestion (food crushing)
        
        Chickens: Proventiculus
        (Glandular region)
        
        chemical digestion
        
        Foregut Fermentation
        
        abomasum (true stomach
        
        RUMINATION
        
        Small Intestine
        
        Villi
        
        surface projections w/in mucosa that increase surface area
        
        3 Regions
        
        Duodenum
        
        Jejunum
        
        Ileum
        
        Cecum
        
        outpouching at the junction between small & large intestines
        
        prolongs transit time of food
        
        HINDGUT FERMENTATION
        
        Coprophagy
        
        re-ingestion of fecal pellets 💩
        
        NOTE:
        Herbivores: Longer intestines (plant is harder to digest)
        Carnivores: Shorter Intestines
        
        Esophagus
        
        movement of food facilitated by mucus
        
        derivative structures
        
        birds: crop
        
        ruminants: rumen, reticulum, omasum
        
        lower esophageal sphincter
        
        located between esophagus & stomach, regulates movement of food entering stomach + prevents retrograde transfer of food
        
        Smooth Muscle
      - Hindgut
        
        Cloaca/Rectum & Anus
        
        Cloaca
        
        single opening that releases digestive, fecal,, and reproductive fluids
        
        absent in most fishes and mammals
        
        Large Intestine
        
        larger lumen, hence "large";
        for water absorption
      - Layers
        
        Mucosa
        
        innermost layer surrounding lumen
        
        Submucosa
        
        Vascularized: BVs, nerve plexus
        
        Muscularis
        
        inner circular muscle, outer longitudinal (except stomach)
        
        Serosa/Adventitia
        
        Serosa
        
        organs suspended by mesentery
        
        Adventitia
        
        retroperitoneal organs (adhered to posterior wall)
      - Modifications
        
        Spiral Valve
        
        helical chamber that increases food transit time
        
        sharks
        
        increases surface area & nutrient absorptive capacity, prolongs transit time
        
        Typhlosole
        
        infoldings of intestinal wall towards lumen
        
        more primite chordates
  - - - secrete mucus/serous fluid that moistens food during mastication
        
        terrestrial vertebrates: ✔️
        fishes: ❌ (rarely observed)
      - Specialized Functions
        
        Snakes: Venom Glands
        
        Birds: Glands for Nest
      - Salivary Glands
        
        most common
        
        3 Pairs
        
        Parotid
        
        Mandibular
        
        Sublingual
        
        SALIVA
        
        mucus, salts, proteins, enzymes
        
        Salivary Amylase
        
        starch digestion
        
        Lingual Lipase
        
        fat digestion
    - - all vertebrates ✔️
      - Functions
        
        Bile production
        
        stored in gallbladder
        
        Hematopoiesis (Fetal Life)
        
        Detoxification (e.g., alcohol)
        
        storage for glycogen (energy-storage molecule)
        
        glucagon releases glycogen from liver
      - Cells
        
        Hepatocytes
        
        sinusoids (sheets)
    - - Exocrine
        
        Digestive Enzymes
        
        Amylase
        
        breaks down carbs
        
        Lipase
        
        breaks down lipids
        
        Trypsin
        
        from trypsinogen, protease
      - Endocrine
        
        hormones produced in Islets of Langerhands
        
        Insulin (Beta Cells)
        
        Glucagon (Alpha Cells)
- - - - Internal Respiration
        
        Between blood
        and tissues
        
        Occurs in the
        capillaries
      - External Respiration
        
        Between blood
        and the environment
        
        O2 to the body;
        CO2 out of the body
    - - GILLS
        
        Unidirectional
        ventilation
        
        Buccal cavity ➡️ Pharynx
        ➡️ Gills ➡️ Opercular Aperture
        
        Sharks: RAM VENTILATION
        
        Forward movement drives
        water through the gills
        
        can also be through swallowing
        
        Internal vs External
        
        Internal Gills
        
        pharyngeal slits/pouches
        
        External Gills
        
        project to external env't
      - Gas Bladders
        
        Swim Bladders
        
        Dorsal aspect
        
        Supplements respiration
        (respiratory gas bladder), buoyancy aid, sound tracking
        
        Forms
        
        Physostomous
        Primitive bony fish
        
        connection between swim bladder & pneumatic duct
        
        Physoclistous
        Later bony fish
        
        no connection between swim bladder & pneumatic duct
        
        Sharks have no
        swim bladder
        
        Cartilage is lighter
        than bones
        
        Shark oil (squalene)
        Less dense than H2O
        
        Pectoral fins
        for steering
        
        Lungs
        
        Bidirectional (tidal)
        ventilation
        
        air enters & leaves through the same channel (mouth/nose)
        
        Connected to the
        environment via
        the trachea
        
        Trachea is guarded by the glottis
        which can close and open
        
        Trachea branches into
        two bronchi leading
        to each lung
        
        Terms
        
        Tidal volume
        
        Air intake per breath
        
        Tidal volume - dead space = air reaching lungs
        
        Dead space
        
        Air in lungs after
        complete exhalation
        
        Anatomic dead space
        
        Air present in airways after exhalation
        
        Physiologic dead space
        
        Anatomic dead space +
        alveolar dead space
        
        1 more item...
    - - CHORIOALLANTOIS
        
        Under the shell, chorioallantois acts as a respiratory organ
        
        shuts down once air enters chick lungs
      - Embryos are wrapped in extraembryonic membranes and enclosed in a shell
        
        Porous shell
        
        Air Space
        
        6 hours before hatch: 🐥 pokes through inner shell membrane into air space
  - - - Transport of gas
      - Blood flow regulation
      - Temperature regulation
      - Waste removal
      - Immunity
    - - Blood
      - Blood Vessels
      - Heart
    - - Lymphatic Vessels
      - Lymphatic Tissue
    - - Single Circulation
        
        Blood passes once
        through the heart per cycle
        
        Fish
      - Double Circulation
        
        Blood passes twice
        through the heart per cycle
        
        Pulmonary circuit
        
        Blood goes to lungs
        
        Systemic circuit
        
        Blood gets circulated to body
  - - - Alveoli
      - Gills
    - - Pumps
        
        Faster flow =
        shorter travel time
        
        Heart, ribcage, diaphragm
        
        Branchial apparatus
    - - Tissue Thickness
        
        Thinner walls
        
        Faster diffusion
      - Tissue Resistance
        
        Moist > dry
        
        Cutaneous Respiration
        
        Direct gas exchange
        on moist skin
        
        Mainly used by
        amphibians
        
        More vascular > less