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.

4. HYDROSTATIC SKELETONS
CNIDARIA
NEMATODE
FLATWORMS
ANNELIDA

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

6. EXOSKELETONS
ARTHROPODSMOLLUSC

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.

8. ENDOSKELETONS
ECHINODERMATASPONGES
CHORDATA

9. 2. THE HUMAN SKELETON

10. 2. THE HUMAN SKELETON

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.

12. Human 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

14. a. AXIAL SKELETON:ii) VERTEBRAL COLUMN
 Vertebrae is divided into
 7 Cervical vertebrae
 12 Thoracic vertebrae
 5 Lumbar vertebrae
 5 fused vertebrae = sacrum
 4 fused vertebrae = coccyx

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.

16. a. AXIAL SKELETON: iii) THORAX
True ribs
False ribs Floating ribs
sternum

17. b. APPENDICULAR SKELETON
Made up of the shoulder (pectoral girdle),
arms, hips (pelvic girdle) and legs.
126 bones.
Function: Movement

18. b. APPENDICULAR SKELETON i) Pectoral girdle
and arm

19. b. APPENDICULAR SKELETON i) Pelvic girdle and
leg

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).

28. 4. STRUCTURE OF A LONG BONE

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,.

30. STRUCTURE OF A SYNOVIAL
JOINT

31. Different types of synavial joints are:
• Ball and socket joint
• Hinge joint
• Pivot joint
• Gliding joint

32. BALL AND SOCKET JOINT:
• Joints of the hips and shoulders
• Allows rotating movement of arms
and legs

33. HINGE JOINT:
• Joints of the elbows, knees, fingers
and toes
• Only allows movement in one
direction.

34. PIVOT JOINT:
• Joints between atlas and axis
• One bone turns on another

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

37. 6. MACRO STRUCTURE OF
SKELETAL MUSCLES
 Epimysium: Surrounds entire muscle
 Perimysium: Surrounds bundles of
muscle fibres (Fascicles)
 Endomysium: Surrounds individual
muscle fibres

38. 6. STRUCTURE OF SKELETAL
MUSCLES

39. MICRO STRUCTURE OF
SKELETAL MUSCLES
 Sarcolemma: Muscle cell membrane
 Myofibrils: Threadlike strands within
muscle fibres
 Actin (thin filament)
 Myosin (thick filament)

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.

42. MOVEMENT OF THE ARM