Sullivan Anatomy Lecture Section 2
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- What composes the SKELETAL SYSTEM?
- All the bones of the body plus the joints formed by their attachments to each other
- What are the main categories of SKELETAL BONES and how many bones comprise them (approximately)
-
Axial 80
Appendicular 126 - What are the FUNCTIONS of the SKELETAL SYSTEM?
-
1. Protection
2. Support
3. Movement
4. Mineral Reservoir
5. Hemopoiesis
6. Energy storage - What is the HISTOLOGY of the BONES OF THE SKELETAL SYSTEM?
-
Haversian Systems (osteons)
a. osteocytes
b. lamella
c. lacunae
d. canaliculi
e. Haversian canal
4 Different Kinds Of Cells
a. Osteoprogenitor Cells (mesenchyme)
b. Osteoblasts
c. Osteocytes
d. Osteoclasts - How are bones classified and what are the types?
-
According to space in between elements
1. spongy (cancellous)
2. compact - What are the features of the TYPICAL LONG BONE?
-
1. Epiphyseal plate
2. Diaphysis
3. Epiphysis
4. Articular Cartilage
5. Periosteum
6. Endosteum
7. Medullary cavity
8. Red bone marrow
9. Yellow bone marrow - Define Medullary Cavity
- The space within a bone that contains the marrow.
- Bone MATRIX COMPOSITION:
-
Organic Framework (33%)
(collagen fibers/ground substance)
Inorganic salts (67%)
(calcium/phosphate salts) - Name the types of BONE OSSIFICATION
- Intramembranous and Endochondral
- Where does INTRAMEMBRANOUS OSSIFICATION occur?
-
1. flat skull bones
2. mandible
3. part of clavicle - Where does ENDOCHONDRAL OSSIFICATION occur?
- In all bones (including long bones, etc) except the flat skull bones, the mandible, and part of the clavicle
- Embrionically, All bones form from what?
- the middle layer of embryonic cells called mesoderm
- What is another name for INTRAMEMBRANOUS OSSIFICATION?
- Dermal Ossification
- What is another name for ENDOCHONDRAL OSSIFICATION?
- Intracartilaginous Ossification
- What are the steps of INTRAMEMBRANOUS OSSIFICATION?
-
1. Mesenchyme cells differentiate into osteoblasts and start to secrete matrix
2. Osteoblasts form spicules of matrix
3. Spicules trap osteoblasts in lacuna
4. Activity slows
5. Trapped osteoblasts called osteocytes
6. Bone growth proceeds outward from center (ossification center)
7. Spicules thicken into trabeculae (spongy bone)
8. Trabeculae connect (compact bone) - Where does INTRAMEMBRANOUS OSSIFICATION begin, what is the beginning point called, and in what direction does it proceed?
- In the center of the bone, or the PRIMARY OSSIFICATION CENTER, and it proceeds outward.
- What does SPICULES mean?
- little skinny sticks
- What are the steps of ENDOCHONDRAL OSSIFICATION?
- 1. Mesenchyme cells form cartilage model. 2. Perichondrium surrounds cartilage model. 3. Osteoblasts differentiate on inner surface of perichondrium. 4. Collar of compact bone surrounds cartilage of diaphysis bone. 5. Chondrocytes and lacunae in diaphysis enlarge (reducing amount of matrix). 6. Calcium deposits in remaining matrix (calcified cartilage). 7. Nutrients can't diffuse. 8. Chondrocytes die leaving hollow spaces. 9. Blood vessels and osteoprogenitor cells enter matrix from periosteum. 10. Osteoprogenitor cells differentiate into osteoblasts. 11. Osteoblasts form trabeculae/bone matrix. 12. This forms PRIMARY OSSIFICATION CENTER in diaphysis. 13. Later SECONDARY OSSIFICATION CENTERS form in epiphyses
- How do long bones increase in length?
- By laying down new bone at epiphyseal plate
- At side of epiphyseal plate toward epiphysis cartilage cells:
- lay down new cartilage
- At the side of the epiphyseal plate toward the diaphysis, cartilage is:
- being replaced by bone
- ENDOCHONDRAL OSSIFICATION starts when?
- 6-8 weeks of development
- INTRAMEMBRANOUS OSSIFICATION starts when?
- 8 weeks of development
- Long bones increase in DIAMETER by:
-
1. Osteoblasts laying down new bone from periosteum
2. Osteoclasts reabsorbing bone from the endosteum - Bone classification by SHAPE:
-
1. Long
2. Short
3. Flat
4. Irregular - Two other types of bone (other than shape types)
- sesamoid and sutural (wormian)
- What are the GROWTH FACTORS for bone?
-
Remodeling & Growth
1. Stress (gravitational, functional)
2. Vitamins (A,C,B12, D)
3. Minerals (Ca, P, Na, Mg)
4. Hormones (parathyroid, calcitonin, thyroxine, GH, sex hormones) - Name the PARANASAL SINUSES
- Frontal, sphenoid, ethmoid and maxillary
-
PARANASAL SINUSES:
What are they physically? - They are air spaces in certain skull and face bones
-
PARANASAL SINUSES:
What are they physically in the nasal cavity? - They are a drain in nasal cavity.
-
PARANASAL SINUSES:
What is their interior histology? - They are lined with ciliated columnar epithelium
- What are the functions of PARANASAL SINUSES?
-
1. Lighten skull
2. Warm air
3. Resonate Sound
4. Protection
5. Produce Mucus - What are FONTANELS?
- Large membranous areas between incompletely ossified skull bones.
- What do FONTANELS do?
- They allow for flexibility and skull growth.
- Name the FONTANELS:
-
1. Anterior
2. Posterior
3. Sphenoid
4. Mastoid - How many ANTERIOR FONTANELs do we have and what bones comprise it/them?
- We have ONE, and it is a meeting of the FRONTAL and PARIETAL bones.
- How many POSTERIOR FONTANELs do we have and what bones comprise it/them?
- We have ONE, and it is a meeting of the OCCIPITAL and PARIETAL bones.
- How many SPHENOID FONTANELs do we have and what bones comprise it/them?
- We have TWO, and they are a meeting of the TEMPORAL, FRONTAL, PARIETAL and SPHENOID bones.
- How many MASTOID FONTANELs do we have and what bones comprise it/them?
- We have TWO, and they are a meeting of the PARIETAL, OCCIPITAL and TEMPORAL bones.
- Name the primary curves of the vertebral column:
-
Posterior thoracic curve
Posterior sacral curve - Name the secondary curves of the vertebral column:
-
Anterior cervical curve
Anterior lumbar curve - When do the PRIMARY CURVES OF THE VERTEBRAL COLUMN develop?
- They are present at birth
- When do the SECONDARY CURVES OF THE VERTEBRAL COLUMN develop?
- They develop after birth
-
Skeletal Differences in males and females:
GENERAL SKELETON -
Male: heavier/thicker
Female: lighter/thinner -
Skeletal Differences in males and females:
PELVIC INLET -
Male: heart shaped
Female: round -
Skeletal Differences in males and females:
OBTURATOR FORAMEN -
Male: oval
Female: triangular -
Skeletal Differences in males and females:
ACETABULUM -
Male: faces laterally
Female: faces anteriorly -
Skeletal Differences in males and females:
PUBIC ARCH -
Male: acute
Female: obtuse -
Skeletal Differences in males and females:
SACRUM -
Male: curved anteriorly
Female: less curved -
Skeletal Differences in males and females:
COCCYX -
Male: close to symphysis
Female: not close -
Skeletal Differences in males and females:
FOREHEAD -
Male: steep/flat
Female: rounded -
Skeletal Differences in males and females:
ORBITS -
Male: square
Female: rounded -
Skeletal Differences in males and females:
PALATE -
Male: broad
Female: narrow -
Skeletal Differences in males and females:
MANDIBLE -
Male: large/square
Female: small, pointed - Name the types of FRACTURES
- 1. Colles' 2. Compression 3. Comminuted 4. Displaced 5. Epiphyseal 6. Greenstick 7. Nondisplaced 8. Pott's 9. Spiral 10. Stress 11. Transverse
-
Define:
POTT'S FRACTURE - Occurs at the ankle and affects both the tibia and the fibula.
-
Define:
COMMINUTED FRACTURE - Shatter the affected area into a multitude of bony fragments.
-
Define:
TRANSVERSE FRACTURE - Break a bone across it's long axis.
-
Define:
SPIRAL FRACTURE - Produced by twisting stresses that spread along the length of the bone.
-
Define:
DISPLACED FRACTURE - Produce new and abnormal bone arrangements.
-
Define:
NONDISPLACED FRACTURE - Retain the normal alignment of the bones or fragments.
-
Define:
COLLES' FRACTURE - A break in the distal portion of the radius. Typically the result of reaching out to cushion a fall.
-
Define:
GREENSTICK FRACTURE - Only one side of the shaft is broken, and the other is bent. This type of fracture generally occurs in children, whose long bones have yet to fully ossify.
-
Define:
EPIPHYSEAL FRACTURE - Tend to occur where the bone matrix is underegoing calcification and chondrocytes are dying. A clean transverse fracture along this line generally heals well. Unless carefully treated, fractures between the epiphysis and the epiphyseal cartilage can permanently stop growth at the site.
-
Define:
COMPRESSION FRACTURE - Occur in vertebrae subjected to extreme stresses, as when you land on your seat in a fall. They are more common when bones are weakened by osteoporosis.
-
Define:
STRESS FRACTURE - A fracture caused by repetitive stress, as may occur in sports, strenuous exercise, or heavy physical labor. Osteoporosis increases the possibility of stress fractures.
- Name the two divisions of the Skeleton and the number of bones in each
-
Axial (80)
Appendicular (126) - The SKULL contains how many bones?
- 29
- The CRANIUM contains how many bones?
- 8
- The FACE, EARS AND HYOID comprise how many bones?
- 21
- Name the bones of the CRANIUM
- Frontal, Ethmoid, Sphenoid, Occipital, Parietal (2), Temporal (2)
- Name the bones of the FACE, EARS AND HYOID
- Vomer, Mandible, Maxillary (2), Zygomatic (2), Nasal (2), Lacrimal (2), Inferior Nasal Conchae (2), Palatine (2), Malleus (2), Incus (2), Stapes (2), Hyoid
- How many bones of the VERTEBRA do we have?
- 26
- How many CERVICAL VERTEBRA do we have?
- 7: the atlas, the axis + 5
- How many THORACIC VERTEBRA do we have?
- 12
- How many LUMBAR VERTEBRA do we have?
- 5
- How many SACRUM do we have?
- 1 consisting of 5 fused vertebra
- How many COCCYX do we have?
- 1 consisting of 3-4 fused vertebra
- How many RIBS do we have?
- 24
- What are the categories of ribs and what are their numbers?
- True (1-7), False (8,9,10), and Floating (11,12)
- What bones comprise the STERNUM?
- The MANUBRIUM, the BODY, and the ZIPHOID PROCESS
- How many bones are in the APPENDICULAR SKELETON?
- 126
- What bones comprise the PECTORAL GIRDLE, and how many of each are there?
- The SCAPULA (2) and the CLAVICLE (2)
- How many bones are in the ARMS and HANDS?
- 60
- What bones comprise the ARMS and HANDS, and how many of each are there?
- HUMERUS (2), RADIUS (2), ULNA (2), CARPALS (16), METACARPALS (10), PHALANGES (28)
- What bones comprise the PELVIC GIRDLE and how many of each are there?
- COXAL BONES (2) consisting of the fused ilia, ischia, and pubic bones
- How many bones comprise the LEGS and FEET?
- 60
- What are the bones of the LEGS and FEET, and how many of each are there?
- FEMUR (2), TIBIA (2), FIBULA (2), PATELLA (2), TARSALS (14), METATARSALS (10), PHALANGES (28)
- Name common disorders of the SKELETAL SYSTEM
-
1. Kyphosis
2. Loordosis
3. Scoliosis
4. Osteoporosis
5. Osteomalacia
6. Osteomyelitis
7. Fractures - Define KYPHOSIS
- Abnormal exaggeration of the thoracic curvature that produces a "roundback" appearance.
- Define LORDOSIS
- Abnormal lumbar curvature giving a "swayback" appearance.
- Define SCOLIOSIS
- Abnormal lateral curvature of the spine.
- Define OSTEOPOROSIS
- A reduction in bone mass and strength sufficient to compromise normal bone function.
- Define OSTEOMALACIA
- A softening of bone due to a decrease in the mineral content.
- Define OSTEOMYELITIS
- A painful infection in a bone, usually caused by bacteria.
- Define FRACTURES
- A break or crack in a bone.
- Define ARTICULATIONS
- Joints between bones
- How are ARTICULATIONS classified?
- Both STRUCTURALLY and FUNCTIONALLY.
- How are ARTICULATIONS classified STRUCTURALLY?
- According to the material between bones at the articulation
- What are the STRUCTURAL classifications of articulations and what is the material between the bones in each?
-
1. Fibrous joints (fibrous connective tissue)
2. cartilagenous joints (cartilage)
3. synovial joints (synovial fluid) - How are ARTICULATIONS classified FUNCTIONALLY?
- According to the movement permitted at the articulation.
- What are the FUNCTIONAL classifications of articulations and what is the movement allowed in each?
-
1. Synarthroses (no movement)
2. Amphiarthroses (slight movement)
3. Diarthroses (freely moveable) - Name the types of FIBROUS JOINTS
-
1. Sutures
2. Syndesmoses
3. Gomphoses -
Define the FIBROUS JOINT:
SUTURES
Give example(s) -
short, SUTURAL LIGAMENTS
held tight
SYNARTHROSES
ie: between flat skull bones - Define SYNOSTOSIS
- When two separate bones fuse together, and the boundary between them disappears. This creates a totally rigid, immovable joint (BONY FUSION)
-
Define the FIBROUS JOINT:
SYNDESMOSES
Give example(s) -
longer, INTEROSSEOUS LIGAMENTS
give
AMPHIARTHROSES
ie: between distal tibia & fibula
between middle radius and ulna -
Define the FIBROUS JOINT:
GOMPHOSES
Give example(s) -
PERIDONTAL LIGAMENT
no movement
SYNARTHROSES
ie: between teeth and sockes in jaw - Name the types of CARTILAGENOUS JOINTS
-
1. Synchondroses
2. Symphyses - What is the material between bones in FIBROUS JOINTS?
- fibrous connective tissue
- What is the material between bones in CARTILAGENOUS JOINTS?
- cartilage
- What is the material between bones in SYNOVIAL JOINTS?
- synovial fluid
-
Define the CARTILAGENOUS JOINT:
SYNCHONDROSES
Give example(s) -
HYALINE CARTILAGE
2 kinds: temporary (epiphyseal plate)& permanent (costal cartilage)
SYNARTHROSES (or AMPHIARTHROSES)
ie: epiphysial plate (temp)
ribs/sternum (perm) -
Define the CARTILAGENOUS JOINT:
SYMPHYSES
Give example(s) -
FIBROCARTILAGE
AMPHIARTHROSES
ie: pubic symphysis - What is the FUNCTIONAL CLASSIFICATION of all SYNOVIAL joints?
- DIARTHROSES / freely moveable
- What are the prominent features of all SYNOVIAL JOINTS?
-
1. hyaline articular cartilage on bone surface
2. articulating surfaces separated by a joint cavity
3. cavity enclosed by fibrous capsule
4. synovial membrane lines cavity
5. membrane secretes synovial fluid into cavity
note: synovial membrane does not cover articular cartilage -- just where articular cartilage is not present - What are the functions of SYNOVIAL FLUID?
-
1. lubricates
2. nourishes
3. cushions / shock absorber -
Define the SYNOVIAL JOINT:
BALL and SOCKET
Give akas, movement, example(s) -
aka SPHEROID, COTYLOID
round head on one fits into concave socket on other
greatest degree of movement
TRIAXIAL
ie: Hip, Shoulder -
Define the SYNOVIAL JOINT:
CONDYLOID
Give akas, movement, example(s) -
aka ELLIPSOIDAL
shallow socket
one surface slightly concave/one surface slightly convex
BIAXIAL
ie: Metacarpals/phalanges (knuckles)
Radius-ulna/carpals -
Define the SYNOVIAL JOINT:
SADDLE
Give akas, movement, example(s) -
aka SELLAR
two opposed curved surfaces (2 saddles)
BIAXIAL
ie: trapezium/metacarpal of thumb (only) -
Define the SYNOVIAL JOINT:
HINGE
Give akas, movement, example(s) -
aka GINGLYMUS
convex surface of one bone fits concave surface of other
UNIAXIAL
ie: Elbow, Knee, Interphalangeal -
Define the SYNOVIAL JOINT:
PIVOT
Give akas, movement, example(s) -
aka TROCHOID
central bony pivot surrounded by collar of bone
allows rotation around a longitudinal axis
UNIAXIAL
ie: Atlas/Axis
Head radius/ulna (proximal) -
Define the SYNOVIAL JOINT:
GLIDING
Give akas, movement, example(s) -
aka PLANE, ARTHRODIA
limited sliding between two almost flat surfaces
NONAXIAL
ie: Articular processes of vertebrae
Between most carpals/tarsals - What are some common DISORDERS OF JOINTS?
-
1. Osteoarthritis
2. Rheumatoid Arthritis
3. Gouty Arthritis
4. Dislocation
5. Sprain
6. Strain
7. Bursitis -
Define Joint Disorder:
OSTEOARTHRITIS -
Articular cartilage degenerates
Affects 85% of people over 70
Joints less mobile, enlarged, painful -
Define Joint Disorder:
RHEUMATOID ARTHRITIS -
Any age
Chronic / Acute
Joints become deformed, inflammed, immovable, impaired function
Autoimmune disease -
Define Joint Disorder:
GOUTY ARTHRITIS -
aka GOUT
Genetic
Excessive amounts of blood uric acid
Deposits in kidneys and joints -
Define Joint Disorder:
DISLOCATION - bones moved out of articulation
-
Define Joint Disorder:
SPRAIN - damage to the ligaments or tendons at a joint
-
Define Joint Disorder:
STRAIN - tear or break in a muscle
-
Define Joint Disorder:
BURSITIS - inflammation of a bursa
- How many muscles are in the body?
- Approximately 600
- MUSCULAR SYSTEM: Notable features
-
Approximately 600 muscles in body
Nearly half the body by weight
Chemical energy of nutrients is converted to mechanical energy in muscles (contraction) - What are the PROPERTIES OF MUSCLES?
-
CONTRACTILITY - ability to shorten
EXCITABILITY - ability to respond to a stimulus
EXTENSIBILITY - ability to stretch or extend
ELASTICITY - if you stretch muscle it will return to normal length - Functions of muscle (contractions):
-
1. Movement
2. Posture/Support
3. Heat production - Name the TYPES OF MUSCLES, where they are found, and their control
-
1. SKELETAL, attached to bones, voluntary
2. SMOOTH, in walls of hollow viscera, involuntary
3. CARDIAC, heart, involuntary - What are notable features of SKELETAL MUSCLE?
-
1. muscle cell = muscle fiber
2. very little matrix in muscle tissue
3. fibers extend full length of muscle
4. each fiber innervated by 1 axon ending (of motor neuron)
5. a single motor axon may innervate 10-200 muscle fibers
6. multinucleate (many nuclei per cell)
7. 30-40 cm (10-16 in) long -
Define:
MOTOR UNIT
(in muscle) - One MOTOR NEURON + all the MUSCLE FIBERS it innervates
- What are the connective tissue components of muscle, where are they found, and what is their histology?
-
Fascia
1. ENDOMYSIUM, around cell membrane of fiber, areolar connective tissue
2. PERIMYSIUM, around bundles of fibers (fasciculi), dense irregular connective tissue
3. EPIMYSIUM, around whole muscle, dense irregular connective tissue -
Define:
FASCIA - Connective tissue fibers, primarily collagenous, that form sheets or bands beneath the skin to attach, stabilize, enclose and separate muscles and other internal organs.
-
RE: MICROSCOPIC STRUCTURE OF MUSCLE FIBER
muscle fiber = - cell
-
RE: MICROSCOPIC STRUCTURE OF MUSCLE FIBER
Cytoplasm = - sarcoplasm
-
RE: MICROSCOPIC STRUCTURE OF MUSCLE FIBER
cell membrane = - sarcolemma
-
RE: MICROSCOPIC STRUCTURE OF MUSCLE FIBER
sarcoplasm contains ... - 100s - 1000s of cylindrical MYOFIBRILS
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RE: MICROSCOPIC STRUCTURE OF MUSCLE FIBER
MYOFIBRILS are made up of ... - 2 types of MYOFILAMENTS
-
RE: MICROSCOPIC STRUCTURE OF MUSCLE FIBER
MYOFILAMENTS -
THIN filaments (actin)
THICK filaments (myosin) -
RE: MICROSCOPIC STRUCTURE OF MUSCLE FIBER
Define SARCOMERE - myofilaments arranged in repeating functional units
-
RE: MICROSCOPIC STRUCTURE OF MUSCLE FIBER
What causes the banding appearance (cross striations)? - arrangement of myofilaments
- Sliding Filament Mechanism
-
1. Tendon
2. Aponeurosis
3. Origin/Insertion/Action
4. Agonist (prime movers) / Antagonist / Synergist -
MUSCLE:
What determines range of MOVEMENT and POWER? - ARCHITECTURE of muscles (how fascicles are grouped)
- Name the ARRANGEMENT OF FASCICULI
-
1. Parallel
2. Pennate
3. Convergent
4. Circular -
Arrangement of Fasciculi:
PARALLEL -
aka LONGITUDINAL
fasciculi parallel to long axis of muscle
flat bands (straps) or spindle
most skeletal muscles in body
produce much movement/ little power
ie: sartorius, rectus abdominus -
Arrangement of Fasciculi:
PENNATE -
have tendons running entire length of muscle
fasciculi short
insert obliquely on tendon
produce little movement/great power
UNIPENNATE, BIPENNATE, MULTIPENNATE -
Arrangement of Fasciculi:
CONVERGENT -
radiate
fasciculi converge from a broad origin into a single narrow tendon
can change direction of pull
less powerful than parallel
ie: pectoralis major -
Arrangement of Fasciculi:
CIRCULAR -
fasciculi arranged in circular pattern
close opening
ie: orbicularis oculi -
Define UNIPENNATE
ie: -
all fasciculi insert on one side of tendon
ie: tibialis anterior -
Define BIPENNATE
ie: -
fasciculi insert obliquely on both side of tendon
ie: rectus femoris -
Define MULTIPENNATE
ie: -
fasciculi attach obliquely along many tendons
ie: deltoid - Criteria used naming of muscles
-
ACTION (flexor carpi ulnaris)
DIRECTION OF FIBERS (rectus abdominis)
LOCATION (tibialis anterior)
NUMBER OF DIVISION (triceps brachii)
SHAPE (trapezius)
POINTS OF ATTACHMENT (sternocleidomastoid)
SIZE (gluteus maximus) - Name the Angular Movements
-
1. Flexion
2. Extension
3. Adduction
4. Abduction
5. Circumduction
6. Rotation
7. Supination
8. Pronation -
Angular Movements
Define:
FLEXION -
a movement in the anterior-posterior plane that reduces the angle between the articulating elements
ie: bending the wrist forward -
Angular Movements
Define:
EXTENSION -
movement in the anterior plane that increases the angle between articulating elements
ie: bending the wrist backwards -
Angular Movements
Define:
ADDUCTION -
a returning movement toward the longitudinal axis of the body (the opposite of abduction)
ie: moving the arm back in toward the body after an outward swing -
Angular Movements
Define:
ABDUCTION -
movement away from the longitudinal axis of the body in the frontal plane.
ie: moving the arm away from the body -
Angular Movements
Define:
CIRCUMDUCTION -
moving your arm in a loop
ie: when drawing a large circle on a chalkboard -
Angular Movements
Define:
ROTATION - left and right rotation of the head produce a "NO"
-
Angular Movements
Define:
SUPINATION - movement that turns the palm forward
-
Angular Movements
Define:
PRONATION - movement that turns the palm facing back
- Name the SPECIAL MOVEMENTS
-
1. Elevation
2. Depression
3. Inversion
4. Eversion
5. Protraction
6. Retraction -
Special Movements
Define:
ELEVATION -
occurs when a structure moves in a superior direction.
ie: you elevate our mandible when you close your mouth -
Special Movements
Define:
DEPRESSION -
occurs when a structure moves in an inferior direction.
ie: you depress your mandible when you open your mouth -
Special Movements
Define:
INVERSION - a twisting motion of the foot that turns the sole inward
-
Special Movements
Define:
EVERSION - a twisting motion of the foot that turns the sole outward
-
Special Movements
Define:
PROTRACTION -
moving a part of the body anteriorly in the horizontal plane
ie: you protract our jaw when you grasp your upper lip with your lower teeth. -
Special Movements
Define:
RETRACTION -
Moving a part of the body posteriorly in the horizontal plane
ie: when you pull your chin back in after sticking it out. - Notable for Smooth Muscle
-
spindle shaped fiber
small (.01-.05 mm)
one nucleus per cell
myofilaments random
usually arranged in 2 layers
- inner...circular
- outer...longitudinal
2 types of smooth muscle - Name the two types of SMOOTH MUSCLE
- Visceral (Single Unit) and Multiunit
-
Smooth Muscle:
VISCERAL (Single Unit)
Contraction initiated by... - local tissue factors and hormones
-
Smooth Muscle:
VISCERAL (Single Unit)
Location: -
wall of small blood vessels
wall of gut
wall of uterus
wall of ureters and urinary bladder -
Smooth Muscle:
MULTIUNIT
Contraction due to... - innervation by motor nerve
-
Smooth Muscle:
MULTIUNIT
Location: -
wall of large arteries
wall of large airways
iris (radial/circular)
arrector pili muscles - Notable re: Cardiac Muscle
-
Striated microscopic appearance
One nucleus per cell
Thickenings at cell membrane junctions (intercalated discs)
Wall of heart
Fibers arranged in 2 branching networks
Stimulation via SPECIALIZED excitation/conductive cardiac muscle fibers. - Name and Define Common Disorders of the MUSCLE SYSTEM
-
Myasthenia Gravis (abnormal neuromuscular junction, weak)
Muscular Dystrophy (degenerationof fibers, atrophy)