the musculo skeletal system support, protection, movement and locomotion
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The Musculo skeletal System Support, Protection, Movement and Locomotion. Skeletal Functions. Framework for support Transmits movement Maintains shape Protects internal organs from mechanical injury Contains and protects the red bone marrow, one of the hemopoietic (blood-forming) tissues - PowerPoint PPT PresentationTRANSCRIPT
The Musculoskeletal SystemSupport, Protection, Movement and Locomotion
Skeletal Functions
Framework for support Transmits movement Maintains shape Protects internal organs from
mechanical injury Contains and protects the red
bone marrow, one of the hemopoietic (blood-forming) tissues
Mineral reservoir - storage site for excess calcium and phosphorus
Storage of fats – yellow marrow
Cytoskeleton Maintains cell shape
Microfilaments Intermediate filaments Microtubules
Protection Enables motion
Cilia Pseudopodia Flagella
Intracellular transport Cell division
Structural support in plants Cell walls Collenchyma
and sclerenchyma tissue
Cellulose and lignin
Hydrostatic skeleton
Fluid-filled closed chambers
Internal pressure generated by muscle contraction
e.g. sea anemone and worms
Exoskeleton
Shelled molluscs (CaCO3)
Arthropods (chitin) Hard segments covering
muscles and visceral organs
Muscles are attached to the exoskeleton
Restricts growth and size of insect molting
Endoskeleton
Endoskeleton Internal, often
mineralized, connective tissue
Muscles on the outside Cartilage –
elasmobranchs Other vertebrates –
cartilage replaced by bone as embryo matures and develops
Appendicular and axial skeleton
Axial skeleton (80 bones) axis of the body support and protection of main
organs• Skull • Sternum• Ribs• Vertebral Column + sacrum and
coccyx Appendicular skeleton (126 bones)
anchors appendages to the axial skeleton
• Upper Extremities• Lower Extremities• Pectoral Girdle• Pelvic Girdle
Types of bones
1. Long bones• Long shaft (diaphysis)• Two joint surfaces
(epiphyses)• Mostly compact bone• e.g. femur, tibia, fibula,
radius, ulna 2. Short bones
• Cube-shaped, mostly spongy bone
• e.g. bones of wrist and ankle, patella
3. Flat bones• Thin and curved• e.g. skull and sternum
4. Irregular bones• Irregular and complicated
shapes• e.g. spine and hips
Joints or articulations
Meeting of two bones Types of joints
Immovable Slightly movable Freely movable
Bone Tissue Compact bone
series of Haversian canals concentric layers of bone
cells (osteocytes) new bone formed by
osteocytes Spongy bone
ends of long bones less dense contains red or yellow
marrow Periosteum
outer layer of bone rich in nerve endings, blood,
and lymphatic vessels inner portion forms new bone
or remodels existing bone
Types of bone cells1. Osteoblasts
immature bone cells manufacture hormones
and enzymes that aid in bone mineralization
2. Osteocytes mature osteoblasts in
lacunae (spaces) form bone, maintain matrix act for calcium
homeostasis3. Osteoclasts
responsible for bone reabsorption and shaping
located on bone surfaces
Bone formation Intramembranous
ossification formation of the flat bones of the skull
Endochondral ossification formation of long bones
Bone remodeling
Resorption of bone (by osteoclasts) followed by replacement of bones (by osteocytes)
Functions to regulate calcium levels, repair damaged bones, and shape and sculpt the skeleton during growth
Rate is regulated by parathyroid hormones (PTH) and Vitamin D
Disorders of the skeletal system
Osteoporosis Reduced bone density
leading to fractures Rickets and
osteomalacia Softening of bones leading to
deformations and fractures Arthritis
Inflammation of joints Bone fractures Scoliosis, kyphosis