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Anatomical Position
Standing upright, head facing front, arms at side with palms forward
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Median (Midsagittal)
Divides the body into right/left halves
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Frontal (Coronal)
Divides the body into anterior/posterior portions
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Transverse (Horizontal)
Divides the body into upper/lower portions
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Superior
Transverse plane splits this from inferior
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Inferior
Transverse plane splits this from superior
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Anterior
- Ventral
- Near the front of the body
Coronal plane splits body from posterior
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Posterior
- Dorsal
- Near the back of the body
Coronal plane splits body from anterior
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Medial
Towards the midline of the body
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Lateral
Further from the midline of the body
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Superficial
Towards the surface
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Deep
Further from the surface of the skin
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Proximal
Toward the point of connection
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Distal
Further from the point of connection
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Extension
Increases the angle at the joint
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Flexion
Decreases the angle at the joint
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Abduction
- Moves away from the body
- On the hands, it is other fingers moving away from the middle finger
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Adduction
- Moves toward the body
- Fingers moves towards the middle finger
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Circumduction
Combination of flexion, extension, abduction, adduction
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Rotation
Head of a bone spins within the socket of another bone
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Types of Rotation
- Medial (internal) or lateral (external)
- Pronation or supination
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Elevation
Movement in superior direction i.e. shoulder shrug up
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Depression
Movement in inferior direction i.e. lower jaw
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Skin
Covers the body externally and has three layers (epidermis, dermis, hypodermis)
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Fascia
Specializations include the superficial and deep layers of tissue below the skin
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Muscle
Consists of skeletal, smooth and cardiac divisions
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Bone
Skeleton consists of an axial skeleton and appendicular skeleton
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Appendicular skeleton
Upper and lower limbs
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Fat
Panniculus adiposis or hypodermis
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Tela subcutanea
The panniculus adiposis along with its underlying superficial membranous fascia
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Average surface area of skin
1.8 square meters
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Functions of the Skin (PASTE)
- Protection: via loose pliable covering, which is generally thicker on extensor surfaces
- Absorption: Vitamin D is stored in the skin, and UV light allows release
- Sensation: temperature regulation
- Excretion: through sweating, non-protein nitrogen, a by-product of liver may be eliminated
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Benefit of Vitamin D
- Facilitates absorption of Ca++ from the GI tract
- Ca++ is an important bone constituent
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Epidermis
Outer layer which consists of vegetative intermitotics (cells that continuously reproduce) with keratinized layer
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Keratin
A protein, which is high in sulfur content
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Dermis (Corium)
Has 2 layers- superficial (papillary layer) and deep (reticular layer)
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Superficial (Papillary Layer)
Consists of papillae that project into the epidermis and carry vasculature to the epidermis
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Deep (Reticular Layer)
Consists of a network of collagen elastic fibers
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Microanatomy of the skin
- Epidermis
- Dermis
- Tela Subcutanea
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Tela Subcutanea
- Hypodermis
- Stratum fibrosum- surrounds exterior of muscle and is superficial to muscle
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Hypodermis
Layer of fat (panniculus adiposis)
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Stratum fibrosum
- Surrounds exterior of muscle and is superficial to muscle
- aka superficial fascia
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Hair
- Distribute over the skin and is absent on glabrous surfaces (lips)
- Contained within the follicle (tube of infolding epidermis)
- Produced at the base of the follicle and consists of keratinized epithelium
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Arrector pili
- Smooth muscle coursing from the root of the hair follicle to the dermis
- Muscle is under sympathetic contral and contraction produces piloerection and squeezing of the heir follicle (goose bumps)
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Sebaceous glands
- Ubiquitous, but absent in the palm of the hands and soles of the feet
- Sebum production clogs the hair follicle and produces acne
- Oily secretion contains cell parts and because the entire secretory cell is lost also called holocrine gland
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Sweat glands
- Ubiquitous, but absent in the glans penis and labia minora
- Termed eccrine gland bc none of the cell is secreted
- Secretions are thin, watery, and high in NaCl
- Glands under sympathetic control
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Apocrine glands
Sweat glands enlarged around the anus and armpit which suggests that only part of the cell is secreted
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Nails
Keratinized epithelium produced at the base of the nail bed
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Mammary gland
Modified sweat gland
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Boundaries of mammary glands in females
- Superior: 2nd or 3rd rib
- Inferior: 6th or 7th costal cartilage
- Lateral: Anterior axillary fold
- Medial: Lateral border of sternum
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Two portions of mammary gland
- Parenchyma (functional part)
- Stroma (supportive, connective tissue part)
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Lymphatic drainage of the breast
- Important because of the prevalence of breast cancer in women
- Cancer follows lymphatic channels to axillary nodes
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Radical Mastectomy
- Surgery done after breast biopsy
- Breast axillary lymph nodes and part of the pectoralis major is removed
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5 groups of axillary lymph nodes
- Lateral group (around axillary artery)
- Central group
- Pectoral group
- Subscapular group
- Apical group
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Smooth tissue
- Walls of hollow viscera (GI tract, blood vessels)
- Innervation via autonomic nervous system
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Cardiac muscle
- Myocardium
- No innervation needed, except for regulation of rate/contractile strength
- Has inherent contractility
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Skeletal muscle
- Voluntary
- 40% of body mass in normal adults and is the type of muscle attached to the skeleton for moving and supporting joints
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Muscle contraction
- Muscle always pulls a joint through an excursion
- Muscle may contract up to 57% of its resting length
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Muscular action
- Movements of joints generally represent combined actions of several muscles:
- -Prime mover
- -Synergists
- -Fixators
- -Antagonists
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Prime mover
- Certain muscles whose main function is to produce a specific action
- Ex: prime mover for elbow flexion is brachialis
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Synergists
Assist prime mover, and compliment its action
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Fixators
Immobilize a joint while another joint is activated
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Antagonists
- Stabilize a joint while the opposite prime movers are contracting, thus preventing undesired actions (dislocation) during movement of the joint
- Ex: while flexors are flexing, extensors are providing stabilization for joints being flexed
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Microanatomy of muscle
- A muscle fiber comprised of muscle cells
- Fibers multinucleated with nuclei located at the periphery of the fiber (syncytial arrangment)
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Epimysium
- Whole sheath around a muscle
- Synonymous with deep fascia, which is connective tissue holding the muscle fibers together
- Consists of collagenous fibers
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Tendons
- Cause a joint to move
- Muscle must attach to bones around the joint through these.
- Formed by aggregation of sarcolemma, which is the cell membrane surrounding the muscle fibers
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Aponeurosis (fleet sheet of connective tissue)
- Attachment of muscles to each other
- Relatively avascular
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Pennate
Featherlike appearance of the muscle fibers approaching tendons
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Examples of pennate
- Unipennate
- Bipennate
- Circumpennate
- Multipennate
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Unipennate
Muscle fibers approach tendon from one side
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Bipennate
Muscle fibers approach tendon from 2 directions in flat plane
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Circumpennate
Muscle fibers approach tendon from all directions
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Multipennate
Multiples of unipennate, bipennate, circumpennate
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Proprioception
The sensory aspect of input into the nervous system regarding the status of a muscle at any given time
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Proprioception provides information for
- Degree of contraction of muscles
- State of tension in the tendon
- Sensory information from joints - monitors the position of the limbs in space, and is necessary for coordination of movement
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Functions of bone
- Support of the body
- Movement (levers)
- Blood producers (from red bone marrow)
- Storage (Ca++, PO4)
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Bone shapes
- Long: humerus, femur
- Short: carpals, tarsals
- Flat: cranium
- Sesamoid: patella
- Wormian: in sutures of the skull
- Irregular: vertebrae
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Two sources of bone development
- Intramembranous ossification
- Endochondral ossification
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Intramembranous ossification
Fibrous membrane, which forms intramembranous bone, typified by the bones of the skull
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Endochondral ossification
Cartilage, which forms endochondral bone as typified by the long bones
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Intramembranous ossification process
- 1. Starts with dens membrane from mesoderm
- 2. Bone forming cells, or osteoblasts, produce osteoid tissue which becomes impregnated with (Ca++ and PO4) to form a matrix
- 3. Periosteum surrounds dense membrane, after osteoblasts from the inner surface of the matrix- periosteum layer deposit bone
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Types of periosteum layer deposit bone
- Spongy bone- random matrix with soft, open spaces which forms the interior of the bone (inner table)
- Compact bone- parallel matrix which is hard and dense, that forms the exterior surface of the bone (outer table)
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Endochondral ossification process
- 1. Cartilaginous mold of the bone forms initially in the developing embryo
- 2. Osteoblasts invade the cartilaginous mold and lay down osteoid, with subsequent impregnation by Ca++ and PO4 matrix
- 3. Gradually the cartilage is replaced by bone; however, cartilage persists at the ends of the bone as epiphyseal plates
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Achondroplasia
- Form of dwarfism that is caused by mutation in fibroblast growth factor receptor 3 (FGFR3).
- In normal development it has a negative regulatory effect on bone groth. In this, the mutated form of the receptor is constitutively active and leads to severly shortened bones
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Bone Marrow Development
- Granular material found within the spongy portion of bones which form blood cells
- Red in children with growth and development and is only retained in certain bones
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Adult bone marrow identification
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Red Marrow
- Sternum, ribs
- Iliac crest
- Vertebral bodies
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Yellow Marrow
- Long bones- nonfunctional, fatty tissue and has replaced
- Red marrow to occupy the "marrow cavity"
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