Comparative Anatomy and Physiology of Animals
Lecture 20 Vertebrate Skeletons 06/01/21
Vertebrate skeleton
- Skeletons support the body against external forces and allow forces to be developed by
muscles to move specific parts of the body.
- Vertebrates adopt a solid internal skeleton comprised of a solid material with a high-elastic
modulus.
Types of skeletal supporting structures
- Supporting structures constructed of two main types of
material.
- These are cartilage and bone.
Cartilage
- Cartilage is a hard but pliant material.
- It is made of specialised cells called chondrocytes, which
produce a large amount of extracellular chondroitin sulphate
matrix interspersed with collagenous or elastic protein fibres.
- Appearance and functional roles dependent on the number and
type of the protein fibres.
Hyaline cartilage
- No fibres are visible when viewed under light microscope.
- It is found in embryonic bones, at the articular ends of long bones, at the tips of the ribs and
in the tracheal rings.
Fibrocartilage
- Collagen fibres are abundant giving mechanical resistance to tensile forces.
- Found in conditions where tensile or warping loads are applied, such as the intervertebral
disks or the pubic symphysis.
Elastic cartilage
- Predominant protein fibre is elastin, which makes the cartilage springy and flexible.
- Found in things such as the internal support for the ear, and the epiglottis.
Bone
- Is a hard and rigid material.
- It is made mostly of collagen, meaning it is a living, growing tissue.
- Collagen is a protein that provides a soft framework, and calcium phosphate is a mineral that
adds strength and hardens the framework.
- This combination of collagen and calcium makes bones strong and flexible enough to
withstand stress.
Types of tissue in bone
- Organic salts arranged in regular, highly ordered unit – Osteon (Haversian system).
- Osteon – series of concentric rings of bone cells and layers of bone matrix around a central
canal that houses blood vessels, lymph vessels and nerves.
- Volkmann’s canals run diagonally through this system and connect blood vessels.
- Layers of bone matrix are called lamellae.
- Unlike cartilage, bone has no direct vascular and nerve supply.
Lecture 20 Vertebrate Skeletons 06/01/21
Vertebrate skeleton
- Skeletons support the body against external forces and allow forces to be developed by
muscles to move specific parts of the body.
- Vertebrates adopt a solid internal skeleton comprised of a solid material with a high-elastic
modulus.
Types of skeletal supporting structures
- Supporting structures constructed of two main types of
material.
- These are cartilage and bone.
Cartilage
- Cartilage is a hard but pliant material.
- It is made of specialised cells called chondrocytes, which
produce a large amount of extracellular chondroitin sulphate
matrix interspersed with collagenous or elastic protein fibres.
- Appearance and functional roles dependent on the number and
type of the protein fibres.
Hyaline cartilage
- No fibres are visible when viewed under light microscope.
- It is found in embryonic bones, at the articular ends of long bones, at the tips of the ribs and
in the tracheal rings.
Fibrocartilage
- Collagen fibres are abundant giving mechanical resistance to tensile forces.
- Found in conditions where tensile or warping loads are applied, such as the intervertebral
disks or the pubic symphysis.
Elastic cartilage
- Predominant protein fibre is elastin, which makes the cartilage springy and flexible.
- Found in things such as the internal support for the ear, and the epiglottis.
Bone
- Is a hard and rigid material.
- It is made mostly of collagen, meaning it is a living, growing tissue.
- Collagen is a protein that provides a soft framework, and calcium phosphate is a mineral that
adds strength and hardens the framework.
- This combination of collagen and calcium makes bones strong and flexible enough to
withstand stress.
Types of tissue in bone
- Organic salts arranged in regular, highly ordered unit – Osteon (Haversian system).
- Osteon – series of concentric rings of bone cells and layers of bone matrix around a central
canal that houses blood vessels, lymph vessels and nerves.
- Volkmann’s canals run diagonally through this system and connect blood vessels.
- Layers of bone matrix are called lamellae.
- Unlike cartilage, bone has no direct vascular and nerve supply.
