The document summarizes the structure and functions of the integumentary and skeletal systems. It describes the key components and layers of skin, such as the epidermis and dermis in vertebrates. It also discusses the various derivatives of the skin, including hair, nails, and glands. For the skeletal system, it outlines the main types of skeletons, including hydrostatic, exoskeletons, and endoskeletons. It provides details on the structure and formation of bones and cartilage.

1. Lecture 2. Support and Protection

2. Integumentary System
Functions:
1. protective wrapping
–
mechanical protection against abrasion and
puncture
–
effective barrier against bacteria
–
moisture proofing against fluid loss or gain
–
protect underlying cells against UV
2. regulatory function
–
temperature regulation

3. Integumentary System
Functions:
3. information getting
–
sensory receptors
4. excretory function
5. respiratory function
6. survival
7. behavioral interactions between individuals

4. Invertebrate Integument
1. Plasma membrane
–
unicellular protozoa
–
gas exchange and waste removal by simple diffusion
–
uptake of dissolved nutrients
Amoeba
Paramecium

5. Pellicle
– thick protein coat found in other protozoa
– offers further environmental protection
– semi-rigid structure that transmits the force of cilia
or flagella to the entire body as the animal moves

6. Invertebrate Integument
2. Epidermis
–
in most multicellular invertebrates
–
single layer of columnar epithelial cells
–
some invertebrates have cuticle over the epidermis
–
delicate and soft in molluscs and contain mucous
glands, some of which secrete calcium carbonate of
the shell

7. Mantle
– pair of folds formed by the dorsal body wall
– outer surface secretes shell

8. (nonchitinous complex
of protein and lipids)
(protein and chitin)
– arthropods have the most complex of invertebrate
integuments
– for protection and skeletal support

9. The arthropod cuticle may be hardened by:
1. calcification – deposition of calcium carbonate in the
outer layers of procuticle

10. The arthropod cuticle may be hardened by:
2. sclerotization – protein molecules bond together with
stabilizing cross-linkages within and between
adjacent lamellae of the procuticle
– formation of a highly resistant and insoluble
protein, sclerotin

11. Molting of arthropods
– epidermal cells divide by mitosis
– epidermis secretes enzyme to digest procuticle
– absorption of digested materials
– new epicuticle and procuticle formed
– new cuticle is thickened and calcified or sclerotized

12. Vertebrate Integument
Skin and derivatives

13. Vertebrate Integument
Skin and derivatives

14. Epidermis
– stratified squamous epithelium
– devoid of blood vessels
– cells of the basal part undergo frequent mitosis
– as outer layer of cells are displaced upward by new
generations of cells beneath, keratinization takes
place
– cornified cells, highly resistant to abrasion and
water diffusion, comprise the outermost stratum
corneum

16. Dermis
– dense connective tissue layer
– contains blood vessels, collagenous fibers, nerves,
pigment cells, fat cells, and fibroblasts
– support, cushion, and nourish the epidermis
– macrophages and lymphocytes provide the first line
of defense

17. Epidermal derivatives

18. Dermal derivatives

20. Similarity of structure of integumentary derivatives
- all are built of similar combinations
of epidermal (keratinized) and
dermal components

22. Hairs
–
epidermal growths that function in protection
–
shaft, root, and follicle
–
sebaceous glands, arrector pili muscle, and hair
root plexus (touch)

23. Hairs
• Types
1. Underhair
•
Dense and soft
•
For insulation
2. Guard hair
•
Coarse and longer
•
For protection against wear and to
provide coloration

24. Nails
•
plates of highly packed, keratinized cells
•
protection, scratching, and manipulation
•
formed by cells in nail bed called the matrix (in
area of lunula)
•
1 mm / week
•
eponychium - cuticle

25. Skin Glands
•
Sebaceous (oil) glands
–
usually connected to
hair follicles
–
fats, cholesterol,
proteins, salts, and cell
debris
–
moistens hair and
waterproofs skin

26. •
Sweat (sudoriferous) glands
–
Eccrine sweat glands
• water, salt, wastes
• hairless regions, scattered
over the body
• function is to cool the body
–
Apocrine sweat glands
• larger
• associated with hair follicles
• more viscous – fatty acids and proteins

27. •
Ceruminous glands
–
modified sudoriferous glands
–
secrete cerumen (ear wax)
–
Cerumen protects the skin of
the ear canal, assists in
cleaning and lubrication, and
provides protection from
bacteria, fungi and insects

28. Mammary glands
•
Secrete milk
•
Thickening of epidermis

29. Animal coloration
–
vivid and dramatic when serving as important
recognition marks or warning coloration
–
subdued or cryptic when used for camouflage

30. 1. Structural color
–
produced by the physical
structure of the surface
tissue; tissue reflects
certain light wavelengths
and eliminates others
–
phase interference effects
of the microscopic
structure of feathers
A. sunlight B. camera flash
–
different response
depending on the direction
or directionality of
illumination

31. 2. color due to pigments
–
Biochromes – pigments produced by chromatophores
–
reflect light rays
–
chromatophores or pigment cells:
•
melanophores/melanocytes (melanin)
•
xanthophores (carotenoid)
•
iridophores (crystals of purine → silvery or
metallic)

33. Skeletal System
Functions: Types:
–
support 1. Hydrostatic skeleton
2. Rigid skeleton
–
protection
–
movement
–
mineral depot
–
blood synthesis

34. 34
1. Hydrostatic Skeleton
•
Functions
–
supports body form
–
provides resistance for the contraction of muscles
to act against
•
Source
–
some organisms use their fluid-filled
gastrovascular cavity
–
others use their fluid-filled coelom (body cavity)

35. Hydra with gastrovascular cavity

36. Earthworm with fluid-filled coelom

38. Muscular hydrostats
–
like hydrostatic skeletons,
these work because they
are composed of
incompressible tissues that
remain at constant volume
–
muscles arranged in
complex patterns

39. 2. Rigid Skeletons
•
consist of rigid elements
•
usually jointed
•
muscle attachment
•
2 principal types
–
exoskeleton
–
endoskeleton

40. •
Exoskeleton - external skeleton
–
Molluscs - composed of calcium carbonate
–
Arthropods - composed of chitin
–
protection and locomotion

41. •
Endoskeleton - internal skeleton
–
Echinoderms and vertebrates
–
mineralized bone and cartilage
–
support, protection, and reservoir of calcium and
phosphorous
–
grows as the animal grows
ü does not limit space for internal organs
ü supports greater weight

42. Notochord
− semirigid supportive axial
rod of protochordates
and all vertebrate larvae
and embryos
− composed of large
vacuolated cells
surrounded by elastic and
fibrous sheaths
− stiffening device
− except in jawless
vertebrates, surrounded
or replaced by the back
bone during embryonic
development Lancelet, Branchiostoma

43. Cartilage
− major skeletal element of
some vertebrates
− soft, pliable tissue that
resists compression
− jawless vertebrates and
elasmobranchs have
purely cartilaginous
skeletons
Lamprey

44. Bone
− living tissue having significant deposits of calcium salts in the
extracellular matrix
− endochondral or replacement bone
− any bone that develops in and replaces cartilage
− i.e. long bone
− intramembranous bone
− any bone that develops without any associated cartilage
− i.e. parietal and frontal bones of the face
− cancellous or spongy bone
− bone composed of thin intersecting lamellae, usually found
internal to compact bone
− compact bone
− bone substance that is dense

45. Long bone

46. Structure of compact bone

47. Bone Growth and Renewal
•
Cartilage structures in early development act as models for
future bones
–
calcium salts deposited in matrix by cartilage cells and
later by osteoblasts
–
endochondral ossification
•
Osteoclasts
–
break down bone
–
remove worn cells
–
deposit calcium in the blood
–
work with osteoblasts to heal broken bones
•
Role of hormones
–
somatotropin, calcitonin, parathyroid hormone

48. Stages of Intramembranous Ossification

49. Stages of Intramembranous Ossification

50. Stages of Intramembranous Ossification

51. Stages of Intramembranous Ossification

52. Stages of Endochondral Ossification Secondary Articular
ossification cartilage
center
Epiphyseal Spongy
Deteriorating blood vessel bone
Hyaline cartilage matrix
cartilage
Spongy Epiphyseal
bone plate
Primary
formation cartilage
ossification Medullary
center cavity
Bone Blood
collar vessel of
periosteal
bud
1 Formation
of bone 2 Cavitation
collar of the 3 Invasion of
around hyaline internal cavities 4 Formation of the
hyaline cartilage by the medullary cavity as 5 Ossification of the
cartilage within the periosteal bud ossification continues; epiphyses; when
model. cartilage and spongy appearance of completed, hyaline
model. bone formation. secondary ossification cartilage remains
centers in the only in the
epiphyses in epiphyseal plates
preparation for stage 5. and articular
cartilages

53. Plan of the vertebrate skeleton
•
2 main divisions
–
axial skeleton (skull, vertebral column, sternum,
and ribs)
–
appendicular skeleton (limbs, fins, wings, pectoral
and pelvic girdles)

54. Human Skeletal System
•
Functions
–
supports and protects the body
–
permits movement
–
provides resistive foundation for muscles to act
against
•
Bones store calcium and phosphate ions
•
Certain bones produce red blood cells

55. 55
The Human Skeleton

56. 56
The Skull

57. Vertebral Column
•
Vertebral column
–
supports the head and trunk
–
protects the spinal cord and roots of spinal nerves
•
Segments (from superior to inferior)
–
cervical - neck
–
thoracic - chest
–
lumbar - small of back
–
sacral – sacrum/pelvic

58. # of Body Abbreviatio
Term
Vertebrae Area n
Cervical 7 Neck C1 – C7
Thoracic 12 Chest T1 – T12
Lumbar 5 or 6 Low Back L1 – L5
Sacrum 5 (fused) Pelvis S1 – S5
Coccyx 3 Tailbone None

59. Rib Cage
•
Protects the heart and lungs, and assists breathing
•
Support by the thoracic vertebrae
–
Twelve pairs of ribs
• true ribs
–
connect directly to sternum
–
seven pairs
• “false” ribs
–
do not connect directly to sternum
–
five pairs

60. 60
The Rib Cage

61. The Appendicular Skeleton
•
Consists of
–
the bones within the pectoral and pelvic girdles
–
the attached limbs
•
Pectoral girdle – bones of the shoulder
–
anterior
–
supports the arms and hands
•
Pelvic girdle - bones of the pelvis
–
posterior
–
supports the legs and feet

62. Bones of the Pectoral
Girdle,
the Arm, and the Hand

63. Bones of the Pelvic
Girdle,
the Leg, and the Foot

64. Classification of Joints
• Fibrous Joints (synarthroses)
– immovable
– between cranial bones, tibia & fibula, radius & ulna

65. Classification of Joints
• Cartilaginous Joints (amphiarthroses)
– slightly movable
– between vertebrae

66. Classification of Joints
• Synovial Joints (diarthroses)
– freely movable
– bones
separated by a
cavity
– ball and
socket, hinge
joints