Support and Movement System

Support and Movement System

• A support system is essential for all living organisms to provide support and enable survival in their environment.

Movement

• Movement involves changing position or location by the organism's entire body or parts.
• Kinesiology studies movement, derived from the Greek "kinein" meaning "to move."

Occurrence of Movement

• At the molecular level, there is Brownian motion, which is the zig-zag motion of molecules.
• At the cellular level, cyclosis, swimming of male gametes, and ciliary/flagellar movement occurs.
• At the organ level, examples of movement include heartbeat and muscle contraction.
• At the organism level, movement includes flying and running.

Types of Movement

• Nonmuscular movement.
• Muscular movement.

Nonmuscular Movement

• Cytoplasmic streaming (cyclosis) facilitates material distribution and pseudopodia formation.
• Amoeboid movement aids in capturing food (Amoeba) and foreign bodies (macrophages).
• Ciliary movement helps propel dust particles, sperm, and ova.
• Flagellar movement helps transport food, oxygen, and fluid circulation (Euglena, Hydra).

Muscular Movement

• It is produced by muscle contraction and relaxation.
• Responsible for moving individual organisms or body parts.

Advantages of Movement

• Movement allows for the mobility of external and internal body components and cellular movement

Locomotion

• It involves changing an organism's place as a whole
• An organism with the ability to move is called "motile."
• Locomotion distinguishes animals from plants.

Advantages of Locomotion

• Allows escape from enemies and predators.
• Facilitates searching for food and water.
• Enables escape from unfavorable environments.
• Aids in finding mates and shelter.
• Supports migration.

Support and Movement System

• The human and animal support system consists of the skeletal and muscular systems.

Endoskeleton

• All vertebrates possess an endoskeleton.
• Bones provide a supportive framework, offering a foundation for muscle attachment.

Musculoskeletal System

• It includes skeletal tissue like bones, cartilage and blood for protection of other body organs.
• Muscular tissue, which are soft tissues of muscles, helps body movements.
• All mammals have an endoskeleton made up of bones and cartilage.
• Bones are composed of calcium, phosphate, and calcium carbonate.
• Cartilage is built of aggrecan, water, and fibers, is semi-rigid and flexible.

Cartilage

• Specialized, semi-rigid, and flexible connective tissue
• Functions to support the body and bear weight.
• Acts as a template for bone formation.
• Offers both rigidity and elasticity, crucial in areas requiring both properties.
• Non-mineralized and contains aggrecan, water, collagen, and elastin fibers
• Earlier phylogenetic origin than bone.
• May be temporary or permanent.
• Supports walls of airways (nose, trachea, larynx, bronchi) and articulates bone surfaces.
• It acts as a template for fetal skeleton and developing long bones

Three Elements of Cartilage

• The three elements of cartilage are cells, fibers, and ground substance/extracellular matrix.
• The perichondrium is the outermost layer of cartilage that provides nutrients to cells and is essential for growth and maintenance.
• Chondrogenic cells lie below the perichondrium and undergo mitosis, differentiating into chondroblasts.
• Chondroblasts are young cartilage cells within lacunae that may undergo mitosis, secreting extracellular matrix, cartilage, and chondrocytes.
• Chondrocytes are mature cartilage cells within lacunae that produce and maintain the extracellular matrix.
• Collagen and elastin are the two types of fibers found in cartilage.
• Ground substance is mainly aggrecan (proteoglycan & glycoproteins), water, collagen, and other constituents.
• Aggrecan is unique to cartilage
• Aggrecan is a cartilage-specific proteoglycan core protein, including chondroitin sulfate and keratan sulfate.
• Aggrecan contains glycoproteins such as chondronectin and chondrocalcin, which are calcium-binding proteins.
• The function of aggrecan is providing a hydrated gel structure to the cartilage.

Two Processes of Cartilage Growth

• Interstitial growth is produced by cell division and the activity of mature chondrocytes with synthesis and expansion inside cartilage, leading to increased length.
• Appositional growth involves activity and differentiation of chondroblasts or perichondral cells with synthesis and enlargement of girth, leading to increased width.

Types of Cartilage

• Hyaline cartilage is blue-white, translucent, and provides low-friction and wear-resistance to aid sliding within bones, designed to bear and distribute weight.
• Found in joints, ribs, sternum, the nasal septum, larynx, and tracheal rings, and has a perichondrium, but is known as the weakest type of cartilage.
• Fibrocartilage which is tough, white, inflexible form of cartilage
• Fibrocartilage provides protection, strength, and resists tearing and compression.
• With dense collagen fibers, it is the strongest type of cartilage and lacks a perichondrium like hyaline cartilage.
• Found within the spine.
• Elastic cartilage has a threadlike network of elastic fibers within the matrix that houses chondrocytes that provides strength and maintains the shape of the epiglottis and external ear.

Features of Cartilage

• Receives nutrition through diffusion from nearest capillaries in the matrix.
• Lacks lymphatics.
• Contains thin canals that provide nutrition to the deepest core.
• Lacks nerve supply, making it insensitive.

Bone

• The hardest connective tissue.

Two Categories of Bones

• Axial bones are located in the head, neck, back, and chest.
• Appendicular bones are located in the appendages or limbs, including arms, legs, pelvis, and shoulders.

Classification of Bone by Shape

• Long bones, such as those in the limbs.
• Short bones, such as those in the ankles and wrists.
• Flat bones, such as the sternum (breast bone).
• Irregular bones, such as the vertebrae.

Functions of Bones

• Bones support and protect
• Bones act as levers
• Provides mineral storage (Calcium and phosphate) and fat storage
• Facilitates hormone and blood production
• Used for hearing, speaking, and movement

Bone Composition

• Bone comprises of inorganic components that contain hydroxyapatite, calcium carbonate, magnesium, sodium, sulfur and Flouride.
• As well as organic components like osteoid which contains ground substance - protein and polysaccharide and collagen fibres; cells (osteoblasts, osteocytes, etc.)

Bone as an organ

• Bone contains nervous tissue, connective tissue, cartilage, and blood vessels.

Two Main Types of Bone

• Compact bone helps forms the outer layer of bone and surrounds spongy bone. It contains osteons, yellow marrow, and shafts which make up 80% of the adult human skeleton.
• Spongy bone, also known as cancellous/trabecular bone, makes up 20% of all bone. It is found at the ends of long bones (epiphysis) and contains crisscrossing branches/networks called trabeculae. Present with endosteum (surrounds parallel lamellae (rod) with osteocytes) and red bone marrow, it helps have compressive forces and is less dense.

Anatomy of Long Bone

• The diaphysis (shaft) consists of compact bone surrounding the medullary/marrow cavity.
• The epiphysis (end) has spongy bone, compact bone and cartilage on the joint surface as well as yellow and red bone marrow.
• The Epiphyseal Plate is a disc of cartilage that grows during childhood.

Bone Marrow

• Red bone marrow is present in the spongy part of long bones (epiphysis), formed by loose reticular tissue, and generates red and white blood cells
• Yellow bone marrow is found in the shaft (diaphysis) of long bones, which stores fat and produces blood cells during excessive blood loss.

Compact vs. Spongy Bone

• Compact bone is present in the diaphysis (central part) of long bones, while spongy bone is in the epiphysis (end parts).
• Compact bone has lamellae arranged in a regular Haversian system/osteon, while spongy bone lamellae are arranged irregularly.

Structure of Compact Bone

• Bone matter is separated into outer periosteum layer, inner endosteum layers, matrix, and bone marrow
• The periosteum is the outer layer that muscles attach to, is made of dense irregular fibrous tissue and contains bundles of collagen fibers. It is absent in any articulating surfaces.
• The endosteum contains the bone marrow cavity of hollow bones and is formed by highly vascular areolar tissue having collagen fibers, blood vessels, and osteoblasts.
• The matrix is a dense, hard substance made of protein ossein and depositions of calcium and magnesium salts.

Elements of Bone

• Bone tissue is a strong, flexible and semi-rigid supporting tissue like cartilage.
• Cells containing osteoblasts and osteocytes along with osteoprogenitor cells and osteoclasts.
• Osteoid, the extracellular bone matrix, comprises collagen fibers, ground substance, such as organic matrix containing proteoglycans and osteonectin as well as only 25% water.
• Almost 70% of bone is made of Hydroxyapatite.

Types Of Bone Cells

• Bone-lining cells are present in periosteum and endosteum and produce bone matrix.
• Osteogenic/osteoprogenitor cells are stem cells that are responsible for the formation of bone.
• Osteoblasts are young bone cells that mineralize bone and secrete matrix that are trapped in the matrix and are transformed into osteocytes
• Osteocytes are mature bone cells located in small fluid lacunae.
• Osteoclasts can also be known as bone phagocytes that help breakdown bone matrix (resorption).

Bone Remodeling

• Remodeling is where old or matured bone is removed by osteoclasts and osteoblasts create new bone.
• It is originated from HSC (hematopoietic stem cell) that create myeloid progenitor and then to osteoclast in a series of steops.
• Osteoclasts break down bone tissue and secrete different enzymes in order to help in bone resorption.
• Osteoblast is created from the MSC (mesenchymal stem cell) and gives rise to osteoblast progenitors and then finally are created.
• Osteoblast sense cracks in the bone, facilitates healing, activates osteoclast to breakdown tissue and creates osteocytes

Compact Bone Structure

• Osteons or Haversian Systems are tree-like structures. An osteon is considered the functional unit of a bone.
• The central Haversian/osteon canal contains both nerves and blood vessels used to supply oxygen and nutrients to bone.
• Lacunae houses the osteocytes along the concentric rings called concentric lamellae.
• Bone tissue contains circumferential and interstitial lamellae, which runs parallel within the periosteum and endosteum.
• The Volkmann's canal connects one central Haversian canal to another housing blood vessels and nerves.
• Osteocytes are arranged in between lamellae, where calcified matrix is typically depositied.

Microscopic Structure of Bones

• Trabeculae consists of endosteum connecting adjacent lacunae for O2 and nutrients
• Lacuna are small spaces adjacent to lamellae.
• Lamellae are thin plates composing of collage, minerals, and matrix.
• Canaliculi are small canals connect adjacent lacuna
• Lacuna conect to the osteon canals through canaliculi for the transportation of oxygen and nutrients.

Collagen in bones

• The significance of the Haversian system lies in its mechanism of the distribution of oxygen and nutrients to the bone cells
• In bone tissue, type I collagen fibres are important in resisting tension, while mineral contributes to withstand to compressive strength.
• Collagen provides strength and flexibility.

Bone Composition

• It maintains the optimal level of calcium as the main homeostatic organ.
• A calcined bone loses all organic matter but remaisn minerals and a demineralized bone lost it's inorganic compounds and looses it's hardness.
• DBM or demineralized bone matter is used in facial resconstructions.

Bone Ossification

• Intramembranous ossification forms bone by direct replacement of mesenchyme.
• Endochondral ossification uses cartillage and acts as the precursor.

Bioenegineering - Prothesis

• Helps those whom have lost limbs due to bone and muscle complications

Composition of Muscles

• Skeletal bones contain skeletal muscle fibre, connective tissue, blood vessels, and nerve fibres.
• Muscle Fibres surrounded by a fibrous connective tissue called endomysuim
• These muscles are composed of bundles and threads named myofibrils. They contain actin and myosin protein filaments, which slide past each other to produce a contraction.

Basic Muscle Traits

• Muscle functions by the use of movement and generating body heat
• They are capable of exitement and can respond to chemical stimuli
• Muscles demonstrate contractability and when adeqautely stimulated can forcefully shorten
• Demonstrate extensibility and are elastic for resting once stretched.

Contraction

• 639-650 of the bodies muscles contract by use of the nervous system
• Muscles are attached to bones via tendons composed of collagen fibres.
• The process of contraction is called Myogenesis.

Muscle Structure

• Endomysium: Innermost layer, surrounding individual muscle fibers and insulates then.
• The Sarcolemma acts as fibre cell membrane.
• Present liquid (cells, cytoplasm) is called sarcoplasm.
• Glycogen and fats for energy also Mitochondria
• Myofibril are cyndrical

Muscle Filaments

• These filaments make up the Sacromere unit
• Sacromere units meet at the z line
• Two proteins are within: Myosin and Actin filaments.

Muscle Proteins

• Contractile Protein controls and dictates muscle function and contraction, including the Actins (thin) and Myosins (thick)
• Regulatory Protein which regulate the ineraction with relaxations.
• Attachment Proteins, such as Neblin.

ATP

• Body fuel is derived from ATP, derived from food intake
• Three major types of contractions including isometric, concentric, and eccentric
• ATP or adenosine triphosphate helps fuel muscle movement and function