Anatomy Exam #2

• Support 
• Protect vital organs
• Movement
• Blood Cell Formation (Hemopoiesis)
• Mineral Storage (Calcium and Phosphate)

Most bones appendages

Carpals and Tarsals

• Cranial 
• Sternum
• Ribs
• Scapulae

• Vertebrae 
• Ossa Coxae
• Certain facial bones
• Calcaneus

Form in tendons:

Patella and Pisiform

• -Stem cells from mesenchyme
• -Give rise to osteoblasts and Osteocytes
• -Periosteum, endosteum, central canal

• -Secret matrix into bone (osteoid)
• -Become Osteocytes

• -Maintain matrix
• -Basically trapped Osteoblasts
• -Detect mechanical stress
• -Rest in small spaces called lacunae

• -Large, multinucleated, phagocytic cells
• -Derived from bone marrow
• -Bone resorption (breakdown extracellular matrix)
• *Hydrochloric acid dissolves minerals
• *Lysosomal enzymes digest protein
• *Liberates calcium and phosphate ions
• -Concentrated in endosteum and periosteum

• Matrix
• -25% Water
• -25% Protein(collagen)-Provides flexability
• -50% Mineral Salts- Provide hardness

• Calcification
• -Crystallization of mineral salts
• -Initiated by bone-building cells (Osteoblasts)

*Bone contains many spaces between cells and matrix. Compact Bone&Spongy Bone

• -Light; supports & protects red bone marrow
• -Consists of trabeculae (little beams)
• -Trabecular arranged along lines of stress
• -Located in areas under less stress
• -Within epiphyses of long bone & interior of long, short, flat irregular bone

• -Dense; Solid
• -Strongest form of bone
• -Forms outer surface of bones & Diaphysis of long bone
• -Consists of Osteons

• Ossification- replacement of pre-existing C.T tissue with bone
• -Begins in embryo
• -Size increases till late teens(female) to late twenties(males)
• Ossification include: Intramembranous bone formation and Endochondral bone formation 
• -Both process result in both types of bone tissue

• -Bone forms withing sheet-like layers of mesenchyme
• -Occurs in flat bone of skull, zygomatic, maxilla, mandible, clavicles
• -Frontanels

• -Bone forms within hyaline cartilage
• -Most bones form through this process
• -Initial cells develop from mesenchyme

• -Bone Lengthening 
• -Occurs during ossification & at epiphyseal plate

• -Bone growth in thickness
• -Occurs within periostuem
• -Osteoblasts produce circumferential lamellae
• -New bone is added to outer surface
• -Osteoclasts widen medullary cavity

The continual deposition of new bone CT and the removal(Resorption) of old bone CT.

• -Helps maintain calcium and phosphate levels
• -

The two processes of Bone Remodeling

• 1) Osteoclasts break down matrix (remove mineral & collagen fibers)
• 2) Osteoblast secrete matrix (add mineral & collagen fibers

• -Alters bone in response to stress
• -Removes injured bone
• -New bone is more resistant to fracture

• Compound - Broken bone protrudes through the skin
• Simple- Bone does not penetrate skin

Splintered, crushed; small pieces between broken ends.

- Usually in elderly and most difficult to treat

Partial fracture; One side breaks, other side bends

-Found in children

One end of fractured bone is forcefully driven into other end

Fracture spirals around long bone axis from twisting forces

At the distal end of fibula, tibia or both

Distal end of radius

• -Fracture without visible break
• -Microscopic fissures
• -No apparent damage to surrounding tissue
• -Result from repeated, strenuous activity
• -Can result from reduced calcium
• -25% involve tibia

• -Fracture Hematoma
• -Fibrocartilaginous Callus (soft)
• -Bony Callus (hard)
• -Bone Remodeling

• -Blood vessels break
• -Mass of blood forms around fracture site
• -Fracture Hematoma forms

• -Fibroblasts from periosteum invade fracture, secret collagen fibers, forming procallus
• -Chondroblasts differentiate from cells in periosteum & secrete fibrocartilage
• -Soft, fibrocartilaginous callus forms

• -Osteoprogenitor cells develop into osteoblasts
• -Osteoblasts secrete spongy bone
• -Fibrocartilage is converted to spongy bone & hard, bony callus forms.

*Then moves into bone remodeling

• -Dead portions of bone fragments removed by osteoclasts
• -Spongy bone is replaced by compact bone around periphery
• -Osteoclasts remove excess bone from interior & exterior surfaces
• -Mineral deposition is gradual; bone cells grow & reproduce slowly

Persistent Suture

(eg Frontal Suture)

• -Between roots of teeth & alveoli of mandible and Maxilla 
• -Periodontal Ligament
• -Synarthrosis (no movement)

• - Articulation in which bones are joined by hyaline cartilage CT
• -Synarthroses 

• E.g. Epiphyseal plate (binds epiphyses&diaphysis) / Sternocostal joint
• -

• -Hyaluronic acid & interstital fluid (Blood plasma)
• -Lubricates and absorbs shock
• -Supplies oxygen and nutrients to cartilage
• -Contain phagocytes that Removes waste and harmful particles

• -Contain joint cavity
• -Articular Cartilage covers articular surfaces
• -Fibrous layer/outer layer attaches to the periosteum 
• -Synovial Membranes - Inner; secretes synovial fluid 

*Fibrous layer is dense CT the strengthens the joint to prevent bones from being pulled apart

• -Found in synovial joints
• -Reduces friction 
• -Made of hyaline cartilage

• -Composed of Dense regular CT
• -Attach bone to bone

• -Connect bone to muscle
• -Dense regular CT

-Lube-like bursa that wrap high friction tendons (wrists, ankle, shoulder, digits)

• -Sacs of CT lined with synovial membrane
• -Contain synovial fluid
• -Reduce friction between bones and: Skin, tendons, bones, ligaments, and muscles.

• -Simplest type of Synovial Joint
• -Flat articular surfaces
• -Least movable diarthroses 
• -Uniaxial 
• (Intercarpal & intertarsal joints)

• -Type of Synovial Joint
• -Biaxial 
• -Flexion/Extension
• -Abduction/Adduction
• (Metacarpophalangeal joints)

• -Type of Synovial Joint
• -Uniaxial
• -Rotation around longitudinal axis
• (Dens of Axis and articular facet of Atlas)

• -Type of Synovial Joint
• -Convex surface fits in concave depression
• (elbow and knee joints)

• -Type of Synovial Joint
• -Triaxial
• -Flexion/Extension
• -Abduction/Adduction
• -Rotation

(Thumb- Trapezium & 1st metacarpal)

• -Type of Synovial Joint
• -Triaxial
• -Flexion/Extension
• -Abduction/Adduction
• -Rotation

(Hip and shoulder joint only)

• -Pad of Fibrocartilage CT
• -Resist compression/Tension stresses
• -Acts as a resilient shock absorber 
• -Amphiarthroses 

(Intervertebral Discs & Pubic Symphysis)

• Fibrous - Dense reg CT
• *Joins bones - Gomphosis & Sutures 
• *Synarthroses
• Cartilaginous - Cartilage joins bones
• *Pubic Symphysis / Intervertebral Disc
• *Amphiarthroses 
• Synovial  - Fluid filled joint cavity
• *Separates bones, ligaments join bones, and capsule surrounds
• *Most joints 
• *Diarthroses

• -Interosseous Ligament (strands of dense CT)
• -Between radius/ulna & tibia/fibula
• -Amphiarthroses

• -Synarthroses- Immobile 
• -Amphiarthroses- Slightly movable 
• -Diarthroses- Freely movable

Excitability- Ability to respond to certain stimuli by generating action potential

Contractility- Ability to contract when stimulated; may result in movement

Extensibility- Ability to stretch w/out damage; allow contraction even if already streatched

Elasticity- Ability to return to original length and shape after contraction or extension

• -Produce Body movement 
• -Stabilize body position
• -Temp regulation
• -Regulate movement of urine/feces
• -Support viscera

• -Subcutaneous layer
• -Areolar CT & Adipose CT
• -Provides pathway for nerves, blood, lumph vessels to enter and exit muscles

-Surround each muscle/Fascicle bundles

• -Between Muscles & around muscle groups 
• -Blends & attaches to tendons
• -Dense irregular CT

-Around each fascicle

• -Around each muscle fiber 
• -Electrically insulate fibers

• Sheet-like arrangements of dense regular CT
• Attaches muscles to bone, sking or other muscles

Plasma membrane of skeletal muscle fiber

• Tiny, deeply penetration invaginations of sarcolemma.
• Open to outside; filled with interstitial fluid 
• Quickly transports muscle impulse from sarcolemma to entire muscle

• Glycogen for ATP synthesis 
• Myoglobin binds oxygen 
• Site for normal muscle fiber activities

• Smooth E.R.
• Stores and releases Ca2+ used for muscle contraction

• Bind sacs next to T-Tubules 
• Site of calcium ion release to promote muscle contraction

• Organized bundles of myofilaments (protein) 
• Long as the muscle itself
• Contractile organelles 
• contain myofilaments that are responsible for muscle contraction

• Contains Actin and regulatory proteins
• Tropomyosin - covers sections of actin
• Troponin- Attaches to actin & tropomyosin/ Binding site for calcium

• Contain Myosin.
• Myosin heads can attach to actin forming corss bridges

• Chains of sarcomeres make up myofibrils
• Contractile units 
• Source of fibers striations

Correspond to length of myosin filaments

Actin (NO MYOSIN) and titan

Anchor for actin; separates sarcomeres

Center of A band; NO ACTIN

• Deliver the stimulus
• Each fiber is controlled by one motor neuron

Point of communication between a mototr neuron and a fiber

• An expanded end of the axon 
• Nerve impulses travel from the axon to the synaptic knob

• Lay within the  cytoplasm of synaptic knob 
• Sac like structure Contain the neurotransmitter acetylcholine

• Sarcolemma of the NMJ
• Invaginated
• Contains ACh receptors

Space between the synaptic knob and Motor end plate

• Nerve impulses arrive at synaptic knob
• Neurotransmitter Acetylcholine diffuses across cleft
• ACh binds to receptors on sarcolemma 
• Muscle impulse spreads along fiber to T-Tubules
• SR releases Ca2+ from terminal cisternae
• Myosin heads attach to actin/Cross bridges
• Myosin heads pivot
• Actin is pulled toward center
• ATP binds to myosin and is broken down
• Sarcomeres shorten, fiber contracts

• A fiber will contract to its maximum extent or not at all
• Singel nerve impulse produces one contraction

• A muscle is composed of motor units
• Motor Unit = A motor neuron+all the fibers it controls 
• Each motor unit responds independently 
• All muscle cells in a motor unti respond maximally, or they dont respond at all

• Strength of contraction is determined by number of motor units stimulated'
• Recruitment: Process of increasing the number of motor units responding 
• Strength increases as number of motor units increase

• Slow Fibers
• Fast glycolytic 
• Intermediate Fibers

• Smallest in diameter 
• High myoglobin content & many capillaries 
• Numerous mitochondria 
• Require oxygen to make ATP
• Slow twitch, fatigue resistant 
• Endurance and posture

• Largest in Diameter 
• Most powerful
• Less myoglobin, few mito and capillaries 
• white in color 
• Faster energy from ATP
• Contract strongly, quickly and fatigue rapidly 
• Sprinting and weight lifting

• Intermediate in diameter, speed of contraction and resistance to fatigue
• High myoglobin, and many capillaries
• Energy from ATP faster
• Faster, shorter contractions
• Walking and Biking

• Aka sphincter
• Located at entrances and exits of internal passageways

• Run parallel to long axis, with central "belly"
• (rectus abdominis, masseter, bicep brachii)

• Widespread fibers converge at common attachment
• Often triangular shaped 

(Pectoralis major)

• Have one of more tendons run most of the length of muscle; short fasicicles
• Pull fibers at an angle 
• Unipennate- Extensor Digitorum 
• Bipennate- Rectus Femoris 
• Multipennate- Deltoid

Continuous, partial contractions in relaxed muscles

Contraction in which muscle shortens, tensions remains constant as movement occurs

Contraction in which muscle is unable to shorten & stay the same length, tension increases

• Enlargement of muscle cells due to exercise 
• The number of actin, myosin myofilaments, Mitochondria, and blood supply increase

Decrease in the size of musclecells due to the lack of use 

The number of Actin, Myosin myofilaments, mitochondria, and blood supply decreases

A rigid rod that moves about a fixed point

The fixed point around which a lever moves (joints)

• Resistance force- Force to be overcome 
• Effort Force- Force required to over come resistance; supplied by skeletal muscles

When the fulcrum is between the effot and the resistance 

Seesaw, tilting head backwards

Resistance is between the fulcrum and the lever 

Wheelbarrow, standing tip toed

The effort/force is between the fulcrum and the resistance

-Most common, flexing the elbow