Lab 5: Transition To Land Flashcards
Largest change in the skeletal and muscular systems from the transition from aquatic to terrestrial?
Development of limbs and increased complexity of the muscles to move them.
-vertebral column strengthened to support weight of the body
-neck allowing head to turn
Land animals have a _________ containing small bones which amplify and transmit sound to the inner ear
What is it homologous to in shakes
Middle ear cavity
Spiracular gill pouch associated with the second visceral arch
Small bones of middle ear are derived from…?
Jaw support elements such as hyoid arch
________ is an example of a primitive amphibian and belongs to the urodele group, which includes ________
Necturus
Terrestrial salamanders
Most common member of Necturus in NA
Necturus maculosis
-common in lakes and rivers in NA
-in Manitoba
Known as the mud puppy
Mudpuppy eating habitats
Hints at night for crayfish, worms
The fins of fish in Necturus have been transformed into
Paired pectoral and pelvic appendages
3 regions of the pectoral limbs of vertebrates
-upper arm or branchium
(Elbow between these)
-forearm or antebrachium
(Wrist between these)
-hand or manus
Pelvic appendages of vertebrates
Thigh or femur
(Knee joint between)
Shank or crus
(Ankle joint between)
Foot or pes
Toes on Necturus
Only 4 are present
-the thumb and big toe or missing
Why does Necturus still have a caudal fin
Still uses fish-like undulations fo locomotion
Fin is still well developed and the body retains segmented axial musculature
Urostyle
A long, still rod of bone compromised of several fused caudal vertebrae on frog
Is very strong segment of the vertebral column that evolved to withstand stresses of hopping
Mouth of Necturus
-Bordered by lips, and above the upper lip is the external nostrils or nares
Where does air enter in necturus
The front of the oral cavity via internal Nate’s or choanae
Eyes of necturus
Small eyes with no eyelids
-larval feature as aquatic larvae do not need protection from drying out.
Land amphibians have fully moveable eyelids
Do salamanders have external eardrums
No, but other amphibians do
Lateral line system in Necturus
Present and most easily seen where it appears as rows of dashes above and below the eye, on the cheek and ventral head surface.
Is a larval feature and disappears in metamorphosed amphibians.
Gas exchange in Necturus
Lungs?
3 pairs of external gills caudal to cheek region
-has lungs and occasionally gulps air at the surface but the lungs primarily function in buoyancy
External gills in necturus
Present in all larval salamanders and are lost as the animals metamorphose into adults.
Cloaca in Necturus
Cloacal apperature marks the caudal margin of the trunk. The male cloaca is more prominent because of the presence of internal cloacal glands
Why is the skull of necturus unusual
High proportion of cartilage because is it a neotenic animal and larvae in general tend to have large numbers of unossified bones
On the front of Necturus upper jaw is a b-shaped _______ which bears _____
Premaxilla
Teeth
The ______ is homologous to the caudal part of the Palaquadrati seen in fish
Quadrate
The bones of the otic capsule housing the inner ear are the _______ and _______
Opisthotic
Prootic
The bones lateral to the foramen magnum (spinal cord) are the ______
Each bear a _____
Exoccipitals
Occipital condyle - rounded processes of bone that occur at specific joint articulations. Help with movement of neck. Mammals and amphibians have 2, reptiles, birds and ancestral tetrapods have 1
The _______ is a small bone in the middle ear cavity of tetrapods derived from the hyomandibula of fish that transmits sound to the inner ear
How is it lacking in necturus
Stapes
Frogs and reptiles have a true ear drum which transmits sound to the stapes, but necturus does not have this. Helps with hearing in air instead of water
Lower jaw difference in necturus
Retains cartilaginous Mandibular cartilage which never becomes a bony articular as in other amphibians
The lower jaw consists of the Mandibular cartilage covered by dermal bones on almost all surfaces
The largest dermal bone, the dentary, covers most of the lateral surface of the jaw
Teeth of Necturus and attachment
Small and homodont (similar in shape)
Attach to the jaw in such a way that they are about the medial surface of the law so that the medial surface of the tooth is longer than the lateral surface=pleurodont
Hyoid apparatus main function in land vertebrates
Support the tongue and the floor of the pharynx
Muscles attached to this are for swallowing and feeding
Of the ventral hyoid arch, two paired elements remain in necturus:
Short hypohyal and long ceratohyal which extends the jaw joint
The first branchial arch consists ventrally of a short __________ which extends caudally from the hypohyal to join with the ________ laterally and a _________ medically.
The second and third branchial arches are reduced and consist of a ______ a tiny________, an _________ and the only element of the third branchial arch, _______
The other visceral arches have been incorporated into the ____
Basibranchial 1
Epibranchial 1
Ceratobranchial 1
Basibranchial 2
Ceratobranchial 2
Epibranchial 2
Epibranchial 3
Laryngeal cartilages
Amphibians and reptiles have four types of vertebrae:
Fish only have:
Cervical
Trunk
Sacral
Caudal
Trunk
Caudal
In necturus, the first vertebra ______ lacks _______ and is specialized to articulate the skull
Cervical
Ribs
In amphibians, the ________ is no longer attached to the back of the skull as in fish, allowing the development of a neck region which permits movement of the head
Pectoral girdle
The trunk of the vertebrae bear _____
Ribs
Zygapophyses
Small projection from the cranial and caudal surfaces of the vertebral arch that Overlap to support adjacent vertebrae
Help to prevent sagging of the vertebral column due to the pull of gravity
Why do modern amphibians have shorter ribs than ancestral forms
Do not use their ribs in lung ventilation
The single vertebra whose ribs articulate with the pelvic girdle is the ______
The rest are ________
Sacral vertebra
Caudal vertebrae, most of which lack ribs and bear hemal arches as in fish
Do amphibians have a sternum?
Yes, mostly
Part of the axial skeleton and supports the ventral chest wall in the midline
Necturus doesn’t have it
The larger bones of the forelimb consist of….
Humerus
Radius - medial side
Ulna
Carpal bones (wrist but are cartilage)
Metacarpals-palm region of hand
2-3 phalanges
There are ______ fingers in the front door of amphibians which are homologous to the second through fifth digits in reptiles, birds and mammals
4
The number of phalanges present in the digits of each front foot from medial to lateral is called the ______
Human vs necturus
Phalangeal formula
Human: 2-3-3-3-3
Necturus: 0-2-2-3-2
The pelvic girdle of necturus attached to the ________
It articulated the largest leg bone:
Sacral rib of the ilium
Femur
Pelvic canal
The ring of bone formed by the sacral vertebra and rub along with the ilium and puboischiadic plate enclosed a space called the pelvic canal through which digestive and Urogenital systems pass before terminating in the cloaca
The other bones of the hind limb in addition to the femur are:
Bones of the ankle are collectively called
Tibia- medial
Fibula
Tarsals
Somatic muscles
Axial muscles of amphibians
Epaxial:
-dorsalis trunci
-interspinalis
Hypaxial:
-external oblique
-internal oblique
-transversus
-rectus abdominus
Myomeres in necturus
Not folded in complex zig zag
Appendicular muscles of necturus
Ventral and dorsal muscles:
Ventral appendicular muscles:
-pectoralis
-supracoracoideus
-procoracohumeralis
-humeroantebranchialis
-forearm flexors
Dorsal appendicular muscles:
-latissmus dorsi
-scapular deltoid
-triceps branchii
-firearm extensor
The appendicular muscles operate the ________
Girdles and limbs
Difference of shark and terrestrial cucullaris
Attached to the last branchial arch and the pectoral girdle and acted to raise the branchial apparatus in sharks
Attached only to the pectoral girdle and helps to draw the scapula cranially and dorsally
On the forearm we can distinguish two groups of muscles:
Extensors- lie on dorsal surface of the forearm
Flexors-lie on the ventral surface of the forearm
Originate on opposite surfaces of the humerus, and insert on the distal forearm, wrist and hand
Hypobranchials in terrestrial amphibians are associated with….
Important for?
The tongue and with more complex swallowing movements
Ventilation of the lungs
Hypobranchials of terrestrial amphibians are the main muscles involved in the ______
Buccal pump
Raises and lowers the floor of the pharynx to draw air into the lungs
Amphibians-breathing on land
Inspiration
-inspiration begins with air entering the external nares, nasal cavity and choanae due to the floor of the oral cavity and pharynx being depressed by the contraction of Hypobranchials muscles
-the increase of volume created negative pressure to inspire air
-the glottis (entrance to the larynx and lungs) is closed as this happens.
-when the choanae and the mouth are closed, the glottis is opened by the contraction of the dilator laryngis muscle, and the floor of the oropharyngeal cavity is raised. This increases pressure to force air through the open glottis into the lungs.
Amphibians expiration
-begins with the floor of the oropharyngeal cavity being depressed while the mouth and choanae remain closed and the glottis is open.
-the negative pressure created by this action draws air out of the lungs through the open glottis.
-finally, the glottis closes and the mouth, choanae, nasal cavity and external nares are opened while the floor of the oropharyngeal cavity is raised again.
-increased pressure forced air out of the body through the mouth and nasal passages
Another term for integument
Skin
Human skin percentage and tissues involved
15% total body weight
1) epithelium-epidermis, glands and hair
2)connective tissue
3)muscle tissue
4)nervous tissue
Function of skin
Protection from abrasion
Protection from excess gain or loss of salts and water
colouration or camouflage
Infraspecific communication
Glandular secretion between sexes for communication
Regulating body temp
Epidermis is composed of ______
At the base of the epidermis one or two cell layers form the _____
Stratified squamous epithelium
Stratum germinativum- cuboidal or columnar cells divide mitotically, giving rise to the layers of cells above the basal layer which differentiated and flattens out as they near the surface
Surface cells eventually slough off either individually, as in humans or in sheets like snakes
Epidermal cells can synthesize….
Keratin, a water insoluble protein that produced a hardened cornified layer at the surface of the skin in many terrestrial vertebrates called the stratum corneum
Layer beneath the epidermis and it’s components
Dermis
-absent in invertebrates
-fibrous connective tissue network composed of collagen and elastic fibers
-fibroblasts: secrete protein fibers
-macrophages to phagocytize pathogens
-smooth muscle: erect hairs for insulation and communication
-nerve and sensory endings for touch and temp receptors
-fat cells
-blood vessels
The dermis supples blood to the _____
Epidermis
A vascular layer in most vertebrates
Tunicate integument
Thin epidermal layer that secreted “so called” tunic
Amphioxus integument
-epidermis consists of 1 layer of columnar epithelial cells that secrete a thin, non-cellular cuticle perforated by a minute pores, somewhat transparent and no scales
-dermis is thin and made up of soft connective tissue, pigment is lacking
Lamprey integument
-epidermis is thin, composed of living cells that secrete a thin cuticle and this is kept moist by secretion of many unicellular mucous glands.
-club cells: may be to secrete a defensive poison or protect cells from invasion by bacteria or viruses
Dermis is thin; composed of connective tissue. Chromatophores located in the Demi’s are responsible for the characteristic colour of the skin. No scales in modern jawless fish
Fish integument
-Stratified squamous epithelialayer forms epidermis. Basal layer cells of epidermis are columnar and divide mitotically to form all cells of the epidermis. Large partially fluid-filled cells in the epidermis known as serous cells which secrete waste material. Pink stained club cells
-Two layers of dermis: surface layer of loose connective tissue and deeper layer of compact dense connective tissue.
Chromatophores called melanophores near boundary of epidermis and dermis which give grey colour of dog fish
Dogfish integument
Placoid scales arise from the dermis and grow up through the epidermis
Responsible for rough surface
3 other dermal scales of fish
Ganoid scales-outer covering of enamel like material: Ganoine: fit closely together and give surface and evenly tiled appearance
Ctenoid scales: numerous comb-like projections on their free edge. Common scale type and arranged overlapping. Basal area has scalloped pattern. Lines of growth can be observed on each scales and these can be used to identify fish age
Cycloid scales: oval in shape and have concentric lines of growth.
Amphibian integument
-integument not well protected especially against desiccation
-epidermis has many glands that for the most part secrete Muskie to lubricate the surface.
-chromatophores are abundant
-superficial layer is cornified: single layer of cells undergoing this change prior to being shed.
-secretion is often taken over by special glands (multicellular) which permits the epidermal cells to assume the rather uniform character and appearance that is found in the epidermis of higher vertebrates
Both mucous secreting and poison glands of frogs are found in which skin layer
Dermis
