LEC3: INTEGUMENTARY SYSTEM

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Created by
Aisha Luaton

Cards (42)

  • INTEGUMENTARY SYSTEM
    Functions:
    1. Protective wrapping
    2. Mechanical protection against abrasion and puncture
    3. Effective barrier against bacteria
    4. Moisture proofing against fluid loss or gain
    5. Protect underlying cells against UV
    6. Regulatory function
    7. Temperature regulation
    8. Homeothermic animals
    9. Information getting
    10. Sensory receptors
    11. Excretory function
    12. Respiratory function
    13. Survival
    14. Derivatives 
    15. Behavioral interactions between individuals
  • INVERTEBRATE INTEGUMENT
    1. Plasma membrane
    2. Unicellular protozoa
    3. Gas exchange and waste removal by simple diffusion
    4. Uptake of dissolved nutrients
  • Pellicle
    • Thick protein coat found in other protozoa
    • Protein that attaches cilia to membrane
    • Offers further environmental protection
    • Semi-rigid structure that transmits the force of cilia or flagella to the entire body as the animal moves
    1. Epidermis
    2. In most multicellular invertebrates
    3. Single layer of columnar epithelial cells
    4. Some invertebrates have cuticle over the epidermis
    5. Delicate and soft in molluscs and contain mucous glands, some of which secrete calcium carbonate of the shell
  • The arthropod cuticle may be hardened by:
    1. Calcification 
    • deposition of calcium carbonate in the outer layers of procuticle
    1. 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
  • 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
  • Mantle
    • Pair of folds formed by the dorsal body wall
    • Outer surface secretes shell
    1. Epidermis
    2. Stratified squamous epithelium
    3. Devoid of blood vessels
    4. Cells of the basal part undergo frequent mitosis
    5. Keratinization takes place as outer layer of cells are displaced upward by new generations of cells beneath
    6. Cornified cells, highly resistant to abrasion and water diffusion, comprise the outermost stratum corneum 
    1. Dermis
    2. Dense connective tissue layer
    3. Contains blood vessels, collagenous fibers, nerves, pigment cells, fat cells, and fibroblasts
    4. Support, cushion, and nourish the epidermis
    5. Macrophages and lymphocytes provide the first line of defense
  • EPIDERMAL DERIVATIVES
    • Feathers, hairs, fur, nail, claw, hooves, scales (reptiles)
    DERMAL DERIVATIVES
    • Scales, antlers 
  • Hairs
    • Epidermal growths that function in protection and insulation
    • shaft , root, and follicle
    • Sebaceous glands, arrector pili muscle, and hair root plexus (touch)
  • Types of hair:
    1. Underhair
    2. Dense and soft
    3. For insulation
    4. Guard hair
    5. Coarse and longer
    6. For protection against wear and to provide coloration
  • Nails
    • Plates of highly packed, keratinized cells
    • Protection, scratching, and manipulation
    • Formed by cells in nail bed called the matrix (in area of lunula)
    • 1mm / week
    • Eponychium - cuticle
  • Matrix

    Area of lunula
  • Nail bed

    • Called the matrix
  • ANIMAL COLORATION
    • Vivid and dramatic when serving as important recognition marks or warning coloration
    • Subdued or cryptic when used for camouflage
    1. Structural color
    2. Produced by the physical structure of the surface tissue; tissue reflects certain light wavelengths and eliminates others
    3. Phase interference effects of the microscopic structure of feathers
    4. Different response depending on the direction or directionality of illumination
    5. Color due to pigments
    6. Biochromes – pigments produced by chromatophores
    7. Reflect light rays
    8. Chromatophores or pigments cells:
    9. melanophores/ melanocytes (melanin)
    10. Xanthophores (carotenoid)
    11. Iridophores (crystals or purine → silvery or metallic)
  • Skin Glands

    • Sebaceous (oil) glands
    • Sweat (sudoriferous) glands
    • Ceruminous glands
    • Mammary glands
  • Sebaceous (oil) glands

    • Usually connected to hair follicles
    • Secrete fats, cholesterol, proteins, salts, and cell debris
    • Moistens hair and waterproofs skin
  • Eccrine sweat glands

    • Secrete water, salts, wastes
    • Located in hairless regions, scattered all over the body
    • Function is to cool the body
  • Apocrine sweat glands

    • Larger
    • Associated with hair follicles
    • Secrete more viscous substance - fatty acids and proteins
    • Restricted to armpits and pubic region (humans), breasts, prepuce, scrotum, external auditory canals
    • Secretion is correlated with certain activities of the reproductive cycle
  • 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
  • Mammary glands

    • Secrete milk
  • HYDROSTATIC SKELETON
    Functions
    • Supports body form
    • Provides resistance for the contraction of muscles to act against
    Source
    • Some organism use their fluid-filled gastrovascular cavity 
    • Others use their fluid-filled coelom (body cavity) 
  • Muscular hydrostats
    • Like hydrostatic skeletons, these work because they are composed of incompressible tissues that remain at constant volume
    • Muscles arranged in complex patterns
    • E.g. octopus tentacles, tongue, elephant trunk/snout
  • Muscular hydrostats
    • Like hydrostatic skeletons, these work because they are composed of incompressible tissues that remain at constant volume
    • Muscles arranged in complex patterns
    • E.g. octopus tentacles, tongue, elephant trunk/snout
  • RIGID SKELETONS
    • Consist of rigid elements
    • Usually jointed
    • Muscle attachment
    • 2 principle types
    • Exoskeleton
    • Endoskeleton
  • Exoskeleton - external skeleton  (soft body animals)
    • Molluscs - composed of calcium carbonate
    • Arthropods - composed of chitin
    • Protection and locomotion
    Endoskeleton - internal skeleton
    • Echinoderms and vertebrates
    • Mineralized bone and cartilage
    • Support, protection, hematopoietic organs, and reservoir of calcium and phosphorus
    • Grows as the animal grows
    • Does not limit space for internal organs
  • Types of endoskeleton
    1. Notochord
    2. Semirigid supportive axial rod of protochordates and all vertebrate larvae and embryos
    3. Composed of large vacuolated cells surrounded by elastic and fibrous sheaths
    4. Stiffening device
    5. Except in jawless vertebrates, surrounded or replaced by the back bone during embryonic development
    1. Cartilage
    2. Major skeletal element of some vertebrates
    3. Soft, pliable tissue that resists compression
    4. Jawless vertebrates and elasmobranchs have purely cartilaginous skeletons'
  • 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
    • Osteoblasts
    • deposit bone matrix
    • become osteocytes once surrounded by bone matrix 
    • Osteoclasts
    • Break down bone
    • Remove worn cells
    • Deposit calcium in the blood
    • They work with osteoblasts to heal broken bones
    • Role of hormones
    • Somatotropin, calcitonin, parathyroid hormone
    1. Bone
    2. Living tissue having significant deposits of calcium salts in the extracellular matrix
    3. bone development 
    4. Endochondral or replacement bone
    5. Any bone that develops in and replaces cartilage (cartilage precursor)
    6. Long bone
    7. Intramembranous bone
    8. Any bone that develops without any associated cartilage
    9. I.e. parietal and frontal bones of the face
    10. bone density
    11. Cancellous or spongy bone
    12. Bone composed of thin intersecting lamellae, usually found internal to compact bone
    13. Compact bone
    14. Bone substance that is dense
  • STAGES OF INTRAMEMBRANOUS OSSIFICATION:
    1. an ossification center appears in the fibrous connective tissue membrane
    2. selected centrally located mesenchymal cells cluster and differentiate into osteoblasts, forming an ossification center
  • Stages of intramembranous ossification
    1. Ossification center appears in fibrous connective tissue membrane
    2. Selected centrally located mesenchymal cells cluster and differentiate into osteoblasts, forming an ossification center
    3. Bone matrix (osteoid) is secreted within the fibrous membrane
    4. Osteoblasts begin to secrete osteoid, which is mineralized within a few days
    5. Trapped osteoblasts become osteocytes
    6. Woven bone and periosteum form
    7. Accumulating osteoid laid down between embryonic blood vessels, which form a random network = network of trabeculae
    8. Vascularized mesenchyme condenses on the external face of woven bone and becomes periosteum
    9. Bone collar of compact bone forms and red bone marrow appears
    10. Trabeculae just deep to the periosteum thicken, forming a woven bone collar that is later replaced with mature lamellar bone
    11. Spongy bone (dipole) consisting of distinct trabeculae, persists internally and its vascular tissue becomes red marrow
  • STAGES OF ENDOCHONDRAL OSSIFICATION
    • Requires cartilage template
    • cartilage structures in early development act as model for future bones
    1. Primary ossification center. Bone collar
    2. Cavitation
    3. Vascularization. Ossification center further develops, bone collar further expands
    4. Formation of medullary cavity as ossification continues. Secondary ossification center. Epiphyseal blood vessel
    5. Ossification of epiphyses. cartilaginous component remains - articulation point
  • PLAN OF THE VERTEBRATE SKELETON
    • 2 main divisions
    • Axial skeleton (skull, vertebral column, sternum, and ribs)
    • Appendicular skeleton (limbs, fins, wings, pectoral and pelvic girdle)
  • 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 (hematopoietic organs)
  • 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 - lower back
    • Sacral - sacrum / pelvic
    • Coccyx - tailbone
    Intervertebral disks of fibrocartilage act as padding
  • RIB CAGE
    • Protects the heart and lungs, and assist breathing
    • Support by the thoracic vertebrae
    • 12 pairs of ribs
    • True ribs
    • Connect directly to sternum
    • 7 pairs
    • “False” ribs
    • Do not connect directly to sternum
    • 5 pairs