CVA Lecture Exam 2

What are 5 functions of the integument?

protection against microbes, heat regulation, respiration, coloration, reception of external stimuli

What are the 2 layers of the integument?

Epidermis - derived from ectoderm, protective/glandular function

Dermis - derived from dermatome, connective function, holds hair/feathers, pigment, nerves, dermal scales

What are the 2 layers of the epidermis?

stratum corneum = dead, upper layer that has lots of keratin which helps skin protect from water loss and bacteria

stratum germinatum = basal layer made of cuboidal cells that differentiate as they move into the stratum corneum.

What are the 2 types of cells in the stratum corneum?

1) those that synthesize keratin, flatten, die, and fall off

2) those that form multicellular glands

What membrane separates the epidermis and dermis?

The basement membrane

What are the 2 layers in the dermis?

stratum laxum = lies directly below the basement membrane, loosley packed cells

startum compatum = below stratum laxum, tightly packed cells

What are the 3 major types of hard tissue associated with skin?

Enamel, Dentine, Bone

Enamel characteristics

hardest tissue (3% organic), made of hydroxyapatite, generally most superficial hard tissue, made in layers and found in teeth, scales, & dermal armor

Dentine characteristics

Softer than enamel (25% organic), has tubules occupied by mesodermal cells, under enamel when present

Bone characteristics

25% organic, deepest layer, may have osteons and may undergo reorganization unlike enamel and dentine

What were extinct agnathan scales made of?

Deep→superficial

lamellar bone, spongy/vascular bone, dentine, ganoine (which is like enamel)

Chondrichthyes skin, when covered with scales, is covered in what type of scales? Shark teeth are also derived from this scale type.

placoid scales

What are the layers in placoid scales (deep → superficial)?

lamellar bone, dentine, enamel

What new function of the integument is introduced in bony fishes?

help maintain water balance by secreting mucous through unicellular glands

What are the 3 types of scales that osteochthyes can have?

cycloid = thin, round and smooth

ctenoid = thin comb-like processes and serrate margin

cosmoid = thick, embedded in skin and act as bony armor

What type of scales do caecilians have?

Tiny osteoderms. Only extant amphibian to have scales

What derived traits did amphibians bring to skin glands?

multicellular glands now secrete into a chamber so that it can be secreted all at once. And now have peratid (poison) glands

Amphibian skin is much like ______ skin.

fish (think catfish)

What new integument characteristics evolved in reptiles which aided them being less dependent on water?

more keratinized epidermal cells, scutes (belly scales) in snakes, plated scales for turtles, and shedding.

What is the difference between snake and lizard shedding?

snake → one piece, lizard → several pieces and eat it

What is the basic structure of a feather?

Calamus (base that’s embedded in skin), Rachis (shaft), Vane, Barb (hooks vanes together)

What are pterylae

The tracts where feathers grow. They don’t grow over the whole body, just in certain areas and lay over bare skin

What are the bare spots where feather don’t grow called?

aptera

Down feather characteristic/function

in babies, no barbs, thermoregulation

Filoplumes function

display

Bristle feather function

focused around the mouth for catching prey

Like scales on reptiles, feathers are _______.

Shed annually

What is the only gland present in avian integument?

*Only present in some species

Sebaceous = produce oil to cover feather for water-proofing

What is unique about the mammalian epidermis?

it’s thicker and has follicles to root hair which will grow through mitosis at the root.

What is the process that causes hair to be shed?

What mitosis at the root stops

What are the layers of hair?

1) medulla at the center

2) cortex surrounding medulla

3) cuticular scale surrounding cortex

*presence of certain layers may vary depending on species (e.g. our baby hairs don’t have a medulla

What are the different types of hair?

Vibrissae = whiskers

guard hairs = protect undercoat

blubber = subcutaneous fat acts as insulation and nutrient resource

What are the different types of glands in mammals?

Eccrine = sweat for cooling

Apocrine = sweat for odor

Mammary = milk

Nail characteristics

grow from nail bed in epidermis. Cornified in ungulates (hooved) but elongated/thickened in claws

Horn characteristics

supported by basal bony structure and surrounded by keratinized epidermal layer. Generally permanent

Antler characteristics

Shed annually during non breeding season and develop under velvet which is lost as they mature.

What are unique about a rhino’s horn?

they are made of keratin fibers that are woven together without a bony core

What’s the scientific name for pigment cells?

chromatophores

What are the different types of chromatophores?

Melanophores = (mammals/birds)contain melanin (red and/or black) and show slow color change

Iridophores = reflect light with platelets of guanine pigment

Xanthophores/erythrophores = yellowish pteridine pigment and reddish carotenoid pigments

Dermal = rapid color change

What is it called when the coloration is in warning (normally for poison)?

aposematic coloration

Is there an animal that has a skeleton completely made of bone?

no

What are the 4 types of cartilage?

Hyaline = clear matrix

Elastic = have elastin fibers

Fibrocartilage = have collagen fibers

Calcified = contain calcium deposits

What is the primary difference between bone and cartilage?

bone has more minerals, calcium-phosphate matrix, deposited in osteons

What are osteons?

ordered units of bone

What is the haversian canal system?

a series of concentric rings made of bone cells forming layers around a central canal through which pass nerves

What are the 2 layers that make up bone tissue?

cortical = Upper is hard/compact

cancellous = lower is spongey/soft

What’s the main difference between reptilian and mammalian bone?

mammalian bones have more canals in the compact bone and have osteons.

What are the different bone cells?

Osteoblasts = produce new bone

Osteoclasts = break down old bone

Osteocytes = maintain equilibrium between minerals and organic material in fully formed bone

What are the 2 methods of skeletal development?

1) Membrane/dermal bone = calcium and osteoblasts deposited within connective tissue near skin surface and trabeculae (rods/tubes) form through that connective tissue and will fuse together for bony tissue to form around it.

2) Cartilage replacement bone = endochondral bone forms within embryonic cartilage while perichondral bone forms around that cartilage. The trabeculae form internal network and spaces between form bone marrow. Ossification process starts from middle to end of bone.

What does epiphysis mean?

end of bone

What does diaphysis mean?

middle of bone

In which general group does the epiphysis remain cartillagenous until adulthood?

Anamniotes

What are epiphysial plates and who has them?

= spaces between diaphysis and epiphysis; birds and mammals have them and are cartilagenous until full-sizedto allow for growth

What is hemopoietic tissue?

bone marrow that produces what/red blood cells and is replaced by yellow bone marrow later in life

What are synarthroses joints?

joints that have little movement but room for growth

What are the 3 types of synarthroses?

Sutures = where 2 dermal bones meet

Synchondroses = sheets of cartilage ossify but remain separated by plate of cartilage

Symphyses = 2 bone halves meet but separated by cartilage

What are diarthroses joints?

Joints that have more movement bc they’re connected by ligaments and collagen sheets and have synovial fluid between bones

What type of bone do some tendons have (tendons that go around corners)?

sesamoid bone

Which is more variable, ligaments or tendons?

ligaments

What is a nuchal ligament?

holds head and neck without muscular effort. the ligament holds the head rather than the muscle

What’s the difference between the chondrocranium, splanchnocranium, dermatocranium?

Chondrocranium = internal support/encase for sensory organs

Splanchnocranium = jaw structures

Dermatocranium = plates surrounding the head

Chondrocranium characteristics

most visible in primitive species and smaller in most derived

Chondrocranium development

1) cartilage forms around brain starting at notochord

2) Cartilaginous rods run from back to front and meet to form basal plate

3) Cartilage surrounds sense organs to form optic, nasal, and auditory capsules

Splanchnocranium choaracteristics

7 Visceral arches composed of cartilage/cartilage replacement bone. Upper jaw detached from skull in primitive vertebrates.

What is the jaw derived from?

1st visceral arch and renamed mandibular arch

What are the different jaw types?

Hyomandibular = Supports jaw in primitive cartilaginous fishes.

Hyostylic = upper jaw that direct connection with chondrocranium

Autostylic = upper jaw articulates/fused to chondrocranium however jaw is unsupported by hyomandibular

What are the 6 groups of the Dermatocranium?

1) Facial series = encircles external nares form snout

2) Orbital series = circles eyes and defines orbit

3) Temporal series = behind orbit

4) Vault series = roofing runs across top to cover brain

5) Palatal series = roof of mouth

6) Mandibular series = encase mandibular cartilage

What was the first vertebrate class to have a brain case?

chondrichthyes

What are 4 things in the skull that changed with Osteichthyes?

1) introduction of a palatoquadrate

2) The optic capsule encloses the ear

3) The lower jaw is only composed of Meckel’s Cartilage which is encased by dermatocranium

4) Hyoid apparatus (which supports floor of mouth and gills) derived from 2nd gill arch.

What are 5 changes that happened in the skull as tetrapods developed?

1) reducing number of separate bony elements through fusion or elimination

2) Autostylic jaw attachment

3) gills→lungs required internal nostrils

4) Function of visceral arches changes from gill support to Hyobranchial apparatus, larynx cartilage, auditory ossicles

5) Dermatocranium moves deeper to be closer to chondrocranium.

How did development of the dermatocranium change with the rise of tetrapods?

includes a stage with temporary gaps between bones (fantanelles) and fusion. May cause the production of intermediate Wormian bones (islands of bone between structures)

Amphibian skull characteristics

chondrocranium mostly cartilage, broad/flat shape

Reptile/bird skull characteristics

introduction of a completely ossified skull and diapsid fenestrae that allowed for stronger jaw

What’s the difference between Diapsida, Synapsida, Euryapsida, and Anapsida?

Diapsida = 2 holes (birds/reptiles)

Synapsida = only bottom hole (mammals)

Euryapsida = only top hole (plesiosaurs/Ichthyosaurs)

Anapsida = no holes (turtles)

What are 4 main differences between a bird and reptiles skull?

1) reptiles had much heavier dermatocranium

2) birds have sclerotic bones (surround the eyes and do not articulate with skull)

3) birds have larger brain:body ratio

4) birds have beaks was modified scales

What are 4 derived traits of the mammal skull?

1) lose sclerotic bone

2) develop turbinate bones in the nasal cavity (spiral shape increase surface area allowing for better olfactory sense) and branchial arches modified into auditory ossicles

3) Hard (anterior) and soft (posterior) secondary palate and epiglottis (food sorting flap)

4) Heterodont, thecodont

What 2 general areas is the postcranial skeleton split up in?

Trunk (vertebral column) and appendicular (limbs)

What is the notochord made of and what happens to it in more derived vertebrates?

Made of vacuolated cells surrounded by fibrous sheath. It gets constricted in high vertebrates because vertebral development

What are the 5 main parts of a vertebrae?

centrum, hemal and neural arch, hemal and neural spine

What are the 5 different centrum types?

Amphicoelous = socket-socket, leaves room for notochord

Opisthocoelous = socket-ball, some reptiles/mammals

Procoelous = ball-socket, reptiles/amphibians

Acoelous = flat-flat, reptiles/mammals

Heterocoelous = saddle-saddle (2 lego hands interlock) only in birds, better support and movement

What’s the difference between Aspidospondyly and Holospondyly?

Aspidospondyly = vertebral elements separate

Holospondyly = vertebral elements fused into one piece

What are the 5 vertebral regions?

Cervical, thoracic (with ribs), lumber (w/out ribs), sacral, caudal.

What are the 2 ways ribs can develop?

1) Intermuscular = develop in myosepta and connects to centrum (fish)

2) Subperitoneal = Ventral ribs form between ventral muscles and lining of coelom (tetrapods, fish)

What are the 2 types of sternum that birds have?

Ratite = no keel → runners

Carinate = massive keel → flyers

What are the 2 articulation points for mammals ribs?

Tuberculum = dorsal, Cupitulum = ventral

What are the 2 ways mammal ribs can articulate with the sternum?

as either true ribs (directly attached by cartilage) or as false ribs (indirect, or not attached)

What is unique about reptilian ribs?

Have gastralia (belly ribs)

What are the 2 general regions of he appendicular skeleton?

Anterior and Posterior girdles

Characteristics of the fish pectoral girdle

include cartilage and dermal bones. Cartilagenous fish have scapulocoracoid while teleost fish have cleithrum

What are the differences in the clavicles in primitive tetrapods, aves, carnivores, and ungulates?

Primitive → interclavicles added

Aves → clavicles fuse into furcula

Carnivores → clavicles reduced

Ungulates → clavicles lost

What is unique about the tetrapod pelvic girdle?

has the obturator foramen (largest foramen)

What is the purpose of fins (not tail)?

control pitch, drag and roll

What are the different types of fish tail?

What are the different types of paired fins?

fin-fold (only in chondrichthyes), ray fins (actinopterygii), Lobed fins (sarcopterygii)

What are the 5 sections of the tetrapod limb?

What’s the difference between suprinating and pronating?

Suprinating = thumbs out, palms up

Pronating = thumbs in, palms down

Who are the exceptions to the rule of early tetrapods having 5 digits?

Ichthiostega (had 7 pes digits) and Acanthostega (had 7 pes and 8 manus)

What is the general phalangeal formula for tetrapods and mammals (who are different from other tetrapods)?

Most Tetrapods → 2, 3, 4, 5, 4

Mammals → 2, 3, 3, 3, 3

What are the 3 types of walking in relation to phalangeal position?

Plantigrade = walk on soles of feet, most primitive (rodents, primates)

Digitigrade = Ankle an