1. UNIT 6: SUPPORT
SYSTEMS IN
ANIMALS
CAMPBELL & REECE
CHAPTER 50 & NOTES ON
EDULINK & LEARNING GUIDE
2. 1. DIFFERENT TYPES OF
SKELETONS
The three main types of skeletons
are:
Hydrostatic skeletons (lack hard
parts)
Exoskeletons (external hard parts)
Endoskeletons (internal hard parts)
3. Hydrostatic Skeletons
A hydrostatic skeleton consists of fluid
held under pressure in a closed body
This is the main type of skeleton in
most cnidarians, flatworms,
nematodes, and annelids
Annelids use their hydrostatic skeleton
for peristalsis, a type of movement on
land produced by rhythmic waves of
muscle contractions.
5. Exoskeletons
An exoskeleton is a hard
encasement deposited on the
surface of an animal
Exoskeletons are found in most
molluscs and arthropods
Arthropod exoskeletons are made
of cuticle and can be both strong
and flexible
The polysaccharide chitin is often
found in arthropod cuticle
7. ENDOSKELETONS
An endoskeleton consists of hard
supporting elements, such as bones,
buried in soft tissue
Endoskeletons are found in sponges,
echinoderms, and chordates
A mammalian skeleton has more than
200 bones
Some bones are fused; others are
connected at joints by ligaments that
allow freedom of movement.
11. a. AXIAL SKELETON: i)Human Skull
Consist of 28 bones
It consists of flat bones that are connected
on the sides by immovable joints called
sutures.
In babies not all the bones of the skull make
contact with each other and fontanels are
formed.
The lower jaw bone (Mandible) is the only
movable bone of the skull – Upper jaw
(Maxilla) is not moveable.
The large opening at the base of the skull is
called the foramen magnum – it is where the
spinal cord enters the skull.
13. a. AXIAL SKELETON: ii)VERTEBRAL COLUMN
Consists of 33 bones called vertebrae.
24 vertebrae are individual single bones.
9 vertebrae are fused to form the sacrum and
coccyx.
Cartilage disks are found between vertebrae.
The s-shaped structure of the vertebral column
and the disks absorb shock and help to
protect the spinal cord.
The first vertebrae – Atlas – carry the weight of
the skull, allows the head to nod.
2nd vertebrae – Axis – allows head to move to
the side
15. a. AXIAL SKELETON: iii) THORAX
Consists of the sternum, 12 pairs of ribs and
thoracic vertebrae.
It protects the heart and lungs.
First 7 pairs of ribs are directly attached to the
sternum by cartilage – called true ribs.
Next 5 pairs – false ribs – last 2 pairs of false
ribs are not attached to the sternum – called
floating ribs
Intercostal muscles found between ribs – aid
in breathing process.
20. 3. FUNCTIONS OF A SKELETON
Support
Movement
Protection
Blood cell production
Storage
Endocrine regulation
21. a. Support
The skeleton provides the
framework which supports the body
and maintains its shape.
The pelvis, associated ligaments
and muscles provide a floor for the
pelvic structures.
Without the ribs, costal
cartilages, and intercostal
muscles, the heart would collapse.
22. b. MOVEMENT
The joints between bones permit
movement.
Movement is powered by skeletal
muscles, which are attached to the
skeleton at various sites on bones.
Muscles, bones, and joints provide
the principal mechanics for
movement, all coordinated by the
nervous system.
23. c. Protection
The skeleton protects many vital
organs e.g.:
The skull protects the brain, the
eyes, and the middle and inner
ears.
The vertebrae protects the spinal
cord.
The rib cage, spine, and sternum
protect the lungs, heart and major
blood vessels.
24. d. Blood cell production
• The skeleton is the site of
haematopoiesis, which takes
place in red bone marrow.
• Haematopoiesisis the formation of
blood cellular components.
25. e. Storage
• Bone matrix can store calcium
and is involved in calcium
metabolism.
• The bone marrow can store iron
and is involved in iron metabolism.
• Bones are not entirely made of
calcium, but a mixture of
chondroitin sulfate and
hydroxyapatite, the latter making
up 70% of a bone.
26. f. Endocrine regulation
• Bone cells release a hormone
called osteocalcin, which
contributes to the regulation of
blood sugar (glucose) and fat
deposition.
• Osteocalcin increases both the
insulin secretion and sensitivity.
27. 4. STRUCTURE OF A LONG
BONE
A long bone is an elongated bone
consisting of a body (diaphysis) and
two terminal parts (epiphyses),
such as found in the leg and arm
bones (femur, radius, phalanges
and others).
29. 5. DIFFERENT JOINTS
In the human body, there are joints
where two or more bones meet in the
skeleton.
Immovable joints do not allow
movement and
Synovial joints are movevable joints
and allow movement of the bones.
Ligaments hold bones together.
Tendons attach muscle to bone,.
35. GLIDING JOINT:
• Joints of the wrist and ankles
• The flat surface of one bone glides
over the surface of a bone next to
it.
36. JOINT DISORDERS
Do research (self study) on the following
disorders, you have to be able to briefly
explain what each of them are (will not
be marked but there will be question in
the exam and semester test about it)
Dislocation
Sprains
Arthritis
Osteoarthritis
Rheumatoid arthritis
41. SKELETAL MUSCLES
Muscles are attached to bones by
means of tendons.
Skeletal muscles produce movement
by contracting.
This exerts a force on tendons, which
in return, pulls on bones.
Muscles occur in pairs which work
antagonistic against each other.
When one contracts the other relaxes.
