Lecture 6: Skeletal and Muscular Systems Flashcards
the body cannot move without
joints
connections bt bones that may or may not permit movement
joints
two bones may be in direct contact with each other or separated by:
- cartilage
- fluid
- fibrous tissue
Joints are classified based on:
Function
Range of motion
Structure
Makeup of the joint
Classification of Joints can be classified….
based on their range of motion (function)
Classification of Joints: 3 Major Categories
*hint: S A D
Synarthrosis (immovable joints)
Amphiathroses (slightly movable joints)
Diarthroses (freely moveable joints)
Classification of Joints: Synarthrosis (immovable joints)
*hint: 4 immovable joints
Sutures (joints found only in skull)
- bones interlocked together; sutural ligament, type of unossified connective tissue
Gomphosis (joint bt teeth and jaw bones)
- periodontal ligaments of the teeth; fibrous
Synchondrosis (joint w/i epiphysis of bone); “with cartilege”
- binds with diaphysis to epiphysis
Synostosis (joint bt 2 fused bones)
- fusion of three coxal bones; totally rigid,no boundary bt fusion
Classification of Joints: Amphiathroses (slightly movable joints)
Syndesmosis (ligaments that connect two bones but limit their motion) “band of ligament”
- bt radius and ulna
- bt tibia and fibula
Symphysis (bones separated by wedge or pad of cartilege)
- between pubic bones of the two coxal bones and intervertebral discs
- fibrous
Classification of Joints: Diarthroses (freely moveable joints)
aka synovial joints
- typically found at end of long bones
- i.e. shoulder joints, elbow join, hip joints, knee joint
Classification of Joints: Diarthroses (freely moveable joints)
FUNCTIONS (3)
Three main functions of synovial joints:
1) Lubrication
2) Nourish chondrocytes
3) Shock absorption
Classification of Joints: Diarthroses (freely moveable joints)
SIX BASIC CHARACTERISTICS OF ALL SYNOVIAL JOINTS
1) Joint capsule
2) Presence of articular cartilege
3) Joint cavity w/ synovial fluid
- lubricates the surfaces of the articular cartilages and reduces friction
- nourishes chondrocytes by entering and exiting the aricular cartilege due to forces acting on the joint
- acts as a shock absorber
4) Synovial membrane
5) Accessory structures (cartilege, tendons, ligaments, bursae sacs - small fluid-filled pockets found where ligaments and tendons rub against other tissues to reduce fricton)
6) Sensory nerves and blood vessels
Classification of Joints: Diarthroses (freely moveable joints)
STRUCTURAL CLASSIFICATION OF SYNOVIAL JOINTS
PLANE JOINTS (gliding joints) => monaxial - movement in only one plane - i.e. carpal/carpal, tarsal/tarsal, vertebrae/vertabrae, clavicle/sternum
HINGE JOINTS => flexion and extension; monaxial
- i.e. elbow and knee
PIVOT JOINTS => rotational movements such as pronation and supination; monaxial
- i.e. atlas/axis
CONDYLAR JOINTS (ellipsoidal joints) => biaxial joint - movement in two planes
- oval articular surface on one bone articulates w depression on another bone
- i.e. radius/capitulum, radius/carpals, phalanges/metacarpals, phalanges/metatarsals
SADDLE JOINTS => allow some circumduction, angular movement without rotation; biaxial
- i.e. pollex/metacarpal
BALL AND SOCKET JOINTS => angular movement and rotation; triaxial
i.e. shoulder joint, hip joint
Muscle Tissue
- muscle contracts and relaxes (i.e. pulls and let’s go; can’t push)
- always a paired system: agonist and antagonist pairs)
- —-> i.e. flexion of elbow: bicep is agonist and tricep is the antagonsist
- when agonist contracts, antagonist relaxes and vice versa
Muscle Arrangement
Know labels on diagram!!!
Myofibrols _ long cylindrical contractile elements arranged in muscle fibers
Sarcoplasm - surrounds myofibrils
Sarcolemma - membrane that surrounds myofibrols
Endomysium - connective tissue covering
All these components form a MUSCLE FIBRE
Muscle Fibres
- composed of myofibrols, sarcoplasm, sarcolemma, endomysium
- muscle fibers are arranged in the muscle fascicle and covered by perimysium
- fascicles are arranged in skeletal muscle and covered by epimysium
Three types of muscle tissue:
Skeletal Muscle
- muscle cells are long, striated, cylindrical and multinucleated
- muscles that move the skeleton
- under voluntary control
Cardiac Muscle
- muscle cells are short, branched and striated w a single nucleus and connected by intercalated discs
- found in myometrium of heart
- cells contract rhythmically
Smooth Muscle
- muscle cells are short w/ pointy ends, nonstriated with single central nucleus
- line digestive tract, respiratory tract, and blood vessels
- under involuntary control
Muscle Function
The skeletal muscle of the body can be subdivided into:
Axial musculature
- muscles that position the head and vertebral column
- muscles that move the rib cage
Appendicular musculature
- muscles that stabilize or move the appendicular skeleton
Muscle Function: The Axial Musculature
- placed into four groups based on function or location
Muscles of :
- the head and neck
- vertebral column
- oblique and rectus muscles
- pelvic floor
Muscle Function: The Axial Musculature
Muscles of :
- the head and neck
Subdivided into several different groups:
- muscles of facial expression (mouth, eye, nose, scalp, neck)
- extraocular muscles (muscles that control eye movement)
- muscles mastication (chewing)
- muscles of the tongue
- muscles of the pharynx (pharyngeal constrictors, laryngeal elevators, palatal muscles)
- muscles of the anterior neck
–> digastric - depresses mandible, opens mouth, and/or elevates larynx
Origin = mandible; Insertion = hyoid bone
–> sternocleidomastoid - flexion of neck, bending of neck towards shoulders
Origin = sternum; Insertion = mastoid process
–> sternohyoid - depresses hyoid bone and larynx
Origin = sternum; Insertion = hyoid bone
–> sternothyroid - depresses hyoid bone and larynx
Origin = sternum; Insertion = hyoid bone
–> thyrohyoid - elevates larynx, depresses hyoid bone
Origin = thyroid cartilage; Insertion = hyoid bone
–> stylohyoid - elevates larynx stylos
Origin = styloid process; Insertion = hyoid bone
Muscle Function: The Axial Musculature
Muscles of :
- the head and neck
- muscles of mastication (chewing)
- muscles of mastication (chewing)
–> masseter - elevates mandible and closes jaw, assists in protracting and retracting mandible and moving mandible side to side
Origin = zygomatic bone; Insertion = mandible
–> temporalis - elevates mandible and closes jaw, assists in retracting and moving mandible from side to side
Origin = temporal lines of skull; Insertion = mandible
–> medial pterygoid - elevates mandible and closes jaw, moves mandible side to side
Origin = palatine bone; Insertion = mandible
–> lateral pterygoid - opens jaws, protrudes mandible, or moves mandible side to side
Origin: maxilla; Insertion = mandible
Muscle Function: The Axial Musculature
Muscles of :
- the head and neck
- muscles of the anterior neck
- muscles of the anterior neck
–> digastric - depresses mandible, opens mouth, and/or elevates larynx
Origin = mandible; Insertion = hyoid bone
–> sternocleidomastoid - flexion of neck, bending of neck towards shoulders
Origin = sternum; Insertion = mastoid process
–> sternohyoid - depresses hyoid bone and larynx
Origin = sternum; Insertion = hyoid bone
–> sternothyroid - depresses hyoid bone and larynx
Origin = sternum; Insertion = hyoid bone
–> thyrohyoid - elevates larynx, depresses hyoid bone
Origin = thyroid cartilage; Insertion = hyoid bone
–> stylohyoid - elevates larynx stylos
Origin = styloid process; Insertion = hyoid bone
Muscle Function: The Axial Musculature
Muscles of:
- the vertebral column
- back muscles (form 3 distinct layers)
Muscle Function: The Axial Musculature
Muscles of:
- the vertebral column
- back muscles (form 3 distinct layers)
- back muscles (form 3 distinct layers)
- -> superficial layer
- -> intermediate layer
- -> deep layer
Muscle Function: The Axial Musculature
Muscles of:
- the vertebral column
- back muscles (form 3 distinct layers)
- -> superficial layer
Muscles of:
- the vertebral column
- back muscles (form 3 distinct layers)
- -> superficial layer = move the neck
SUPERFICIAL LAYER
- trapezius - neck extension
ORIGIN = occipital bone; INSERTION = scapula
- latissimus dorsi - extension, adduction, and medial rotation of shoulder; the swimmer’s muscle
- levator scapulae - elevates scapula (“levitates”)
- rhomboid muscles - adduction and downward rotation of scapula
