Exercise 15: Endoskeletal System

• Endoskeleton - internal mechanical support system made of hardened material
• In invertebrates, the endoskeleton is often composed of deposits of what compound?

  Calcium Carbonate
• Within the soft tissues of some invertebrates, a few examples of the endoskeleton are the cuttlebone of the cuttlefish, test of the sea urchin.
• The squid endoskeleton is the pen, which is made up of chitin
• What is the vertebrate endoskeleton mainly composed of?

  bone, cartilage, ligament
• Bones are strong structures - joined together by ligaments - that function mainly for the support of the body and for the protection of vital organs
• Cartilage - soft and can be found in areas requiring flexibility
• Vertebrae skeletal system is divided into 2 sections. What are they?

  Axial skeleton, Appendicular skeleton
• The axial skeleton consists of the skull, the primary bone of the head, and the posterior vertebral column, composed of bones known as the vertebrae
• The appendicular skeleton includes the pectoral girdle, a mask-shaped group of bones which support the chest region; the pelvic girdle, a u-shaped set of bones which supports the hip area; and the rest of the appendages
• Skull - formed from the bones of the head region
• Skull consists of two parts: cranium, a set of bones enclosing the brain and some sense organs, and the mandible, or the lower jaw.
• The skull is mostly composed of plates of bone
• The plates of the skull are separated by jagged lines called sutures, forming an immovable joint known as synarthrosis
• Hyoid - separate bone, supports the floor of the mouth and serves as an anchor for the tongue
• What do the olfactory capsules house?

  nasal cavity
• In the anterior portion of the skull, among the two pairs of openingss, what are the larger ones called?

  orbits
• What do the orbits of the skull house?

  eyeballs
• What is the rim of the upper jaw called?

  maxillary arch
• What can be found between the olfactory capsules on the anterior end?

  Premaxillary processes
• On the posterior end of the skull, you will find a median opening what is it called?

  foramen magnum
• The foramen magnum has two protrusions on each side. What are these called?

  occipital condyles
• The occipital condyles articulate with what?

  first vertebra
• immediately lateral to the occipital condyles are two structures of what?

  otic capsules
• What do the otic capsules house?

  inner ear
• neurocranium - cavity within the foramen magnum where the brain is enclosed
• Label the toad axial skeleton idol( ಠ ͜ʖಠ)

  A) Orbits

  B) neurocranium

  C) Premaxillary processes

  D) maxillary arch

  E) Foramen magnum

  F) occipital condyles

  G) Otic capsules

  
• Label the following found in the toad lower jaw.(☞ ͡° ͜ʖ ͡°)☞

  A) Maxillary arch

  B) Hyoid

  
• The vertebral column of the toads and frogs is composed how many vertebrae?

  10
• Atlas - first vertebra wherein its a ring-like bone which articulates with the occipital condyles of the skull
• The atlas is the only cervical vertebra in toads and frogs.
• The remaining nine vertebrae comprised the trunk vertebra
• Typical - the first seven trunk vertebrae (2-8)
• Sacral vertebra - ninth vertebra with expanded transverse processes articulating with the pelvic girdle
• urostyle - last vertebra which is an elongated, rod-like structure, which consists of several fused vertebrae
• In frogs and toads, ribs are absent
• Label the following found in the toad vertebral column. Make daddy proud.( ͡°👅 ͡°)

  A) atlas

  B) typical

  C) sacral

  D) urostyle

  
• Centrum - serves as the body of the vertebra and is a solid elliptical mass found on the ventral side.
• Procoelous - condition wherein the centrum of the vertebrae are concave anteriorly and convex posteriorly
• Neural canal - dorsal to the centrum here the spinal cord passes through