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104 Cards in this Set

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Name the bones of the shoulder, arm, forearm, wrist and hand
Shoulder: Scapula, clavicle
Arm: Humerus
Forearm: Radius(lateral), Ulna(medial)
Wrist: Carpals (Scaphoid, Lunate, Triquetral, Pisiform, Trapezium, Trapezoid, Capitate, Hamate)
-------Stop Letting The Professor Touch The Cadaver's Hand
Hand: Metacarpals (5), Phalanges (proximal, middle, distal)
-------thumb does not have middle
Movement of the scapula
Rotation, Abduction/Adduction, Retraction/Protraction
Movement of the glenohumeral joint
Flexion/Extension, Abduction/Adduction, Medial/Lateral Rotation, Circumduction
Movement of the forearm
Pronation/Supination
Movement of the elbow joint
Flexion/Extension
Movement of the wrist joint
Abduction/Adduction, Flexion/Extension, Circumduction
Movements of the fingers
Thumb: Opposition of thumb, Extension/Flexion and Abduction/Adduction (perpendicular)
Fingers:Flexion/Extension and Abduction/Adduction
Describe a synovial joint
Most common and movable joint:
1. articular surfaces covered with articular (hyaline) cartilage
2. articular surfaces enclosed in joint capsule to form synovial cavity
3. joint capsule reinforces joint and produces synovial fluid
4. two layers:
a. outer fibrous layer reinforced by extracapsular ligaments
b. inner synovial layer (synovium) consists of vascularized connective tissue that produces fluid (hyaluronic acid/glycoproteins)
Examples of synovial joints in the upper extremity
Glenohumeral joint, elbow joint, wrist joint
What is the glenoid labrum and what is it's function?
It is a fibrocartilaginous structure that deepens and expands the glenoid cavity
What is the joint capsule, what does it do and where is it on the glenohumeral joint?
The joint capsule is a fibrous sheath that surrounds the synovial membrane to provide reduce friction between the tendons and adjacent joint capsule and bone. It covers the glenoid cavity and around the humeral head, extending medially to the shaft of the humerus.
What are the ligaments surrounding the glenohumeral joint and what do they do? Where are they in relation to the joint?
Superior, middle and inferior glenohumeral ligaments; coracohumeral ligament; transverse humeral ligament
What is the difference between dynamic and static stabilizers of a joint?
A dynamic stabilizer is a contractile tissue such as muscle while a static stabilizer is non-contractile such as a ligament and help control end-range range of motion
What are the muscles of the rotator cuff?
Supraspinatus, infraspinatus, teres minor and subscapularis (SITS)
Trapezius: function, innervation, and blood supply
Elevates scapula and helps to rotate scapula during abduction of the humerus above horizontal; it is innervated by the spinal accessory nerve (XI); transverse cervical artery
Deltoid: function, innervation, and blood supply
Major abductor of arm (beyond initial 15* done by supraspinatus); innervated by axillary nerve; deltoid branch of thoracoacromial artery
Levator scapulae: function, innervation, and blood supply
Elevates scapula; innervated by dorsal scapular nerve; dorsal scapular artery
Rhomboid minor: function, innervation, and blood supply
Elevates and retracts scapula; innervated by dorsal scapular nerve; dorsal scapular artery
Rhomboid major: function, innervation, and blood supply
Elevates and retracts scapula; innervated by dorsal scapular nerve; dorsal scapular artery
Supraspinatus: function, innervation, and blood supply
Part of rotator cuff muscles; initiates abduction of arm to 15* at glenohumeral joint; innervated by suprascapular nerve; suprascapular artery
Infraspinatus: function, innervation, and blood supply
Part of rotator cuff muscles; lateral rotation of arm at glenohumeral joint; innervated by suprascapular nerve; suprascapular and circumflex scapular arteries
Teres minor: function, innervation, and blood supply
Part of rotator cuff muscles; lateral rotation of arm at glenohumeral joint; innervated by axillary nerve; subscapular and circumflex artery
Subscapularis: function, innervation and blood supply
Part of rotator cuff muscles; medial rotation of arm at glenohumeral joint; innervated by subscapular nerves; subscapular artery
Teres major: function, innervation and blood supply
Medial rotation and extension of arm at glenohumeral joint; innervated by subscapular nerves; subscapular and circumflex scapular arteries
Latissimus dorsi: function, innervation and blood supply
Adduction, medial rotation and extension of arm at glenohumeral joint; innervated by thoracodorsal nerve; thoracodorsal artery
Long head of triceps brachii: function, innervation, and blood supply
Accessory adductor and extensor of arm at glenohumeral joint, extension of forearm at elbow joint; innervated by radial nerve: branches of deep brachial artery
Pectoralis major: function, innervation, and blood supply
Flexion, adduction, and medial rotation of arm at glenohumeral joint; innervated by medial and lateral pectoral nerves: dorsal scapular artery
Subclavius: function, innervation, and blood supply
Pulls tip of shoulder down, pulls clavicle medially to stabilize sternoclavicular joint; innervated by nerve to subclavius: thoracoacromial trunk
Pectoralis minor: function, innervation, and blood supply
Pulls tip of shoulder down, protracts scapula; innervated by medial pectoral nerve: pectoral branch of thoracoacromial trunk
Serratus anterior: function, innervation, and blood supply
Protraction and rotation of scapula, keeps medial border opposed to thoracic wall; innervated by long thoracic nerve; circumflex scapular artery
Normal vascular supply of the shoulder region
Axillary artery: 6 main branches
1. Superior thoracic artery: small, supplies upper regions of medial/anterior axillary walls
2. Thoracocromial artery: short, forms four branches (deltoid, pectoral, clavicular and acromial) supplying related regions, as well as the breast
3. Lateral thoracic artery: supplies medial/anterior axillary wall as well as the breast
4. Subscapular artery: largest branch, major supply to posterior axillary wall
-----divides into two branches, circumflex scapular artery and thoracodorsal artery
5. Anterior circumflex humeral artery: smaller than posterior, originates from lateral side of artery; supplies glenohumeral joint and surrounding tissues
6. Posterior circumflex humeral artery: branch of axillary artery, supplies muscles around humeral head and glenohumeral joint
Suprascapular artery: originates from subclavian artery, supplies supraspinatus and infraspinatus
Axillary vein: continuation of basilic vein, cephalic vein drains the lateral/posterior part of hand, forearm and arm and joins axillary superior to pectoralis minor
What are the two common injuries to the rotator cuff and which muscle is commonly involved?
Supraspinatus is the most commonly involved muscle because it's tendon lies within a space of fixed dimensions and swelling of the muscle, excess fluid within the bursa or bony spurs can produce impingement when the arm is abducted. The other injury, tendinopathy, occurs because the tendon has poor blood supply and can lead to degenerative changes due to repeat trauma; this weakens the tendon, leading to tearing.
Label the brachial plexus
What spinal cord segments contribute to the musculocutaneous nerve?
C5-C7
What spinal cord segments contribute to the median nerve?
C5-T1
What spinal cord segments contribute to the ulnar nerve?
C8-T1
What spinal cord segments contribute to the axillary nerve?
C5-C6
What spinal cord segments contribute to the radial nerve?
C5-T1
What path does the musculocutaneous nerve take to its distal termination?
As the terminal branch of the lateral cord, it passes laterally to penetrate the coracobrachialis muscle and passes between the biceps brachii and the brachialis muscles and innervates all three flexor muscles in the anterior compartment of the arm, terminating as the lateral anti-brachial cutaneous nerve.
What path does the median nerve take to its distal termination?
As a combination of both lateral and medial cords, it passes into the arm anterior to the brachial artery and down into the forearm where it innervates the muscles of the anterior compartment, except flexor carpi ulnaris and the medial half of flexor digitorum profundus. It continues into the hand to innervate the three thenar muscles, the two lateral lumbrical muscles (index/middle fingers) and the skin over the palmar surface of the lateral 3.5 digits and the lateral side of the palm and middle of the wrist.
What path does the ulnar nerve take to its distal termination?
It is the terminal branch of the medial cord and it passes through the arm and forearm to the hand to innervate all intrinsic muscles of the hand except for the thenar/lumbrical muscles. In the forearm, it innervates the flexor carpi ulnaris and the medial half of the flexor digitorum profundus. It also innervates the skin over the palmar surface of the little finger, the medial half of the ring finger, associate palm and wrist and the skin over the dorsal surface of the medial part of the hand.
What path does the axillary nerve take to its distal termination?
It originates from the posterior cord and passes inferiorly/laterally along the posterior wall to exit the axilla through the quadrangular space, innervating the deltoid and teres minor, eventually becoming the superior lateral cutaneous nerve to innervate the skin in that region.
What path does the radial nerve take to its distal termination?
It is the largest terminal branch of the posterior cord and it passes out of the axilla into the posterior compartment of the arm and it and its branches innervate all the muscles in the posterior compartment of the arm and forearm and the skin on the posterior aspect of the arm, forearm, lower lateral surface of the arm and the dorsolateral surface of the hand
If the musculocutaneous nerve was severed/injured, what motor and sensory functions would be lost?
Motor: All muscles in the anterior compartment of the arm

Sensory: skin on the lateral side of the forearm
If the median nerve was severed/injured, what motor and sensory functions would be lost?
Motor: All muscles in the anterior compartment of the forearm (except flexor carpi ulnaris/flexor digitorum profundus), three thenar muscles, two lateral lumbrical muscles

Sensory: Skin over the palmar surface of the lateral 3.5 fingers and over the lateral side of the palm and middle of the wrist
If the ulnar nerve was severed/injured, what motor and sensory functions would be lost?
Motor: All intrinsic muscles (except the thenar and lateral lumbrical muscles) as well as flexor carpi ulnaris and flexor digitorum profundus

Sensory: Skin over the palmar surface of the medial 1.5 fingers and associated palm/wrist and skin over the dorsal surface of the medial 1.5 fingers
If the axillary nerve was severed/injured, what motor and sensory function would be lost?
Motor: Deltoid, teres minor (abduction, lateral rotation of the arm)

Sensory: Skin over upper lateral part of arm
If the radial nerve was severed/injured, what motor and sensory function would be lost?
Motor: All muscles in the posterior compartment of arm and forearm

Sensory: Skin on the posterior aspects of the arm and forearm, the lower lateral surface of the arm, and the dorsal lateral surface of the hand
What compartments make up the arm?
Anterior compartment: contains muscles that primarily flex the elbow joint

Posterior compartment: contains muscles that primarily extend the elbow joint

Cubital fossa: area of transition between arm and forearm, anterior to elbow joint, composed of tendon of biceps brachii, brachial artery and median nerve
Name the muscles in the anterior compartment of the arm.
Coracobrachialis, brachialis and biceps brachii
How is the anterior compartment of the arm innervated?
The musculocutaneous nerve provides innervation to all the muscles
How is the posterior compartment of the arm innervated?
The radial nerve innervates the triceps brachii, and provides sensory innervation via the lateral brachial cutaneous nerve
How is blood supplied to the anterior compartment of the arm?
The brachial artery, with paired brachial veins running along side as well as the basilic and cephalic veins
How is blood supplied to the posterior compartment of the arm?
The profunda brachii artery, a branch of the brachial artery, with the basilic and cephalic veins medial and lateral
Name the muscles of the posterior compartment of the arm.
Triceps brachii
What are the compartments of the forearm?
Anterior compartment: flex wrist and digits and pronate hand

Posterior compartment: extend wrist and digits and supinate hand

Carpal tunnel: passage between forearm and hand
Name the muscles of the anterior compartment of the forearm.
Three layers: (1)superficial, (2)intermediate and (3)deep (8 total)
1. Four muscles: flexor carpi ulnaris, palmaris longus, flexor carpi radialis and pronator teres (wrist flexors/pronator)
2. Flexor digitorum superficialis (finger flexor)
3. Three muscles: Flexor digitorum profundus, flexor pollicis longus, and pronator quadratus (finger flexor/pronator)
Name the muscles of the posterior compartment of the forearm.
Two layers: (1)superficial and (2)deep (12 total)
1. Seven muscles: brachioradialis, extensor carpi radialis longus, extensor carpi radialis brevis, extensor digitorum, extensor digiti minimi, extensor carpi ulnaris and anconeus
2. 5 muscles: supinator, abductor pollicis longus, extensor pollicis brevis, extensor pollicis longus and extensor indicis
What innervates the anterior compartment of the forearm?
All muscles are innervated by the median nerve except flexor carpi ulnaris and the medial half of flexor digitorum profundus, which are innervated by the ulnar nerve. Superficial radial nerve provides sensory innervation for anterolateral aspect of forearm.
What innervates the posterior compartment of the forearm?
The deep radial nerve innervates muscles, and the deep muscles are innervated by the posterior interosseous nerve, a continuation of the radial nerve
How is blood supplied to the anterior compartment of the forearm?
Brachial artery, branches to become radial and ulnar arteries and anterior interosseous artery, deep veins accompany arteries and drain into brachial vein
How is blood supplied to the posterior compartment of the forearm?
Branches of the posterior interosseous artery, the radial artery and the anterior interosseous artery, with veins accompanying arteries
Name the intrinsic hand muscles, their functions and innervations.
1. Palmaris brevis: improves grip, innervated by ulnar nerve
2. Dorsal interossei (4): abduction of index, middle and ring fingers at MCP, innervated by ulnar
3. Palmar interossei (4): adduction of index, middle and ring fingers at MCP, innervated by ulnar
4. Adductor pollicis: adducts thumb, innervated by ulnar
5. Lumbricals (4): flex MCP joint while extending IP joints (make L shape in hand), medial two innervated by ulnar, lateral two innervated by median
6. Thenar muscles (3): innervated by median nerve
-----opponens pollicis: medially rotates thumb
-----abductor pollicis brevis: abducts thumb at MCP
-----flexor pollicis brevis: flexes thumb at MCP
7. Hypothenar muscles (3): innervated by ulnar nerve
-----opponens digiti minimi: lateral rotates pinkie
-----abductor digiti minimi: abducts pinkie at MCP
-----flexor digiti minimi: flexes pinkie at MCP
What forms the carpal tunnel and what are its contents?
It is formed by the carpal arch (carpals: lunate, pisiform, triquetrum, hamate, capitate, trapezoid, trapezium, scaphoid) and flexor retinaculum (ligament)

Contains: four tendons of the flexor digitorum superficialis, four tendons of the flexor digitorum profundus, and the tendon of the flexor pollicis longus as well as the median nerve. A synovial sheath surrounds the digitorum tendons, with a separate one around pollicis
What are the signs and symptoms of carpal tunnel syndrome?
Pressure is put on the median nerve, with pain and pins and needles reported and weakness in the thenar muscles. Gently tapping on the median nerve over the retinaculum produces these symptoms (Tinel's sign)
How is the hand supplied by blood?
The radial and ulnar arteries form two interconnected vascular arches, superficial and deep in the palm, with the radial supplying the thumb and lateral side of the index finger and the ulnar supplying the rest. Veins form their own interconnected network, with the deep veins following the arteries and the superficial veins draining into the dorsal venous network, where the cephalic vein originates laterally and the basilic vein originates medially
How are the shoulder strength tests performed and what muscles is it testing?
By placing one hand on superior aspect of shoulder and grasping arm with other hand, ask patient to bend elbow.
-----To test flexion, ask patient to move arm forward.
-----To test extension, ask patient to push backwards.
-----Then to test external rotation (infraspinatus/teres minor), stand in front of patient, have patient bend arms at elbow to 90* and placing hands on wrists, have patient push outward.
-----To test internal rotation (subscapularis), cross arms and have patient push inwards.
-----To test supraspinatus, perform Job's test, bringing patient's arms to 90* of abduction, then moving arms forward 30*, then tilting arms so thumbs face down, then ask patient to push up on hands.
-----To test subscapularis, use lift off test, move patient's hand to back at waist level, palm out and place hand on patient's hand, asking patient to push away from body.
------------All tests must be performed on both sides to accurately gauge problems/weaknesses
How are the shoulder special tests performed?
Rotator cuff injury (supraspinatus tear): drop arm test
-----have patient stand, ask to raise arms above head and slowly lower arms to 90* (with tear, cannot lower and arm will drop to side)
Rotator cuff impingement:
------Neer's sign: stabilize patient's scapula, then pronate affected arm and passively forward flex as high as possible (positive test leads to pain in patient)
------Hawkin's test: forward flex patient's arm to 90*, bend elbow and forcibly internally rotating humerus (creates pain)
Biceps tendon/labral pathology:
------Speed's test: have patient forward flex arm against resistance with arm supinated (pain indicates pathology)
Labral tears: (more sensitive)
------O'Brien's test: forward flex patient's arm, abduct to 20*, internally rotate so thumb down, ask to resist downward pressure, then rotate so thumb up and again ask to resist downward pressure (pain/clicking with thumb down, reduced with thumb up)
------Crank's test: labral pathology; forward flex arm, flex elbow, push forward on elbow while internally/externally rotating arm (pain, catching, clicking is positive)
Glenohumeral joint instability tests:
------apprehension test: patient can stand or sit, place hand on superior shoulder, abduct to 90* and externally rotate humerus (look of apprehension is positive)
------relocation test: performed after apprehension, put posterior pressure on proximal humerus produces relief
------anterior release test: patient supine, with arm abducted, pressure on proximal humerus (pain upon release of pressure)
Describe loose connective tissue and its function.
The matrix contains loosely arrange collagen fibers and numerous cells; most cells are "transient" and have immune function, while some are "fixed" (fibroblasts) to form/maintain the matrix.
Function: supports structures under some pressure/low friction, can be found with most epithelia, surrounding blood vessels, nerves and muscle
Describe regular dense connective tissue and its function.
Matrix contains high quantity of very organized collagen fibers with few cells (mostly fibroblasts). It is generally poorly vascularized.
Function: it provides high tensile strength, resisting stretching, and is found in tendons and ligaments
Describe dense irregular connective tissue and its function.
Matrix contains collagen fibers arrange without definite orientation with few cells (mostly fibroblasts) and is poorly vascularized.
Function: provides compression strength to resist stress from all directions, usually found associated with loose connective tissue.
Describe the structure and function of collagen.
Structure: at least 16 different types, made of three α-chains that associate in a right-handed triple helix; each chain has a characteristic amino acid sequence where every third AA is Gly; the tropocollagen helices associate with one another to form collagen fibers
Describe the structure and function of adhesive glycoproteins.
Structure: formed from homo- or hetero-dimers, bonded using di-sulfide bonds, proteins have specialized areas for specific functions

Function: facilitate the attachment of cells to ECM, such as integrins; alter the growth, survival, morphology, differentiation and motility of cells
Describe the structure and function of proteoglycans.
Structure: family of macromolecules with protein cored covalently bonded to at least one GAG; highly negatively charged, more GAG=more charge

Function: helps to organize and stabilize the matrix by interaction with other molecules like collagen; attracts water due to neg. charge; present on cell surface to regulate cell-cell interaction and growth factor binding.
Describe the structure and function of glycosaminoglycans.
Structure: long, unbranched polysaccharides consisting of repeating di-saccharide units, highly negatively charged

Function: associate with water due to neg. charge and create hydrated gels with high viscosity and low compressibility

Ex: hyaluronic acid, dermatan sulfate, chondroitin sulfate, heparin, heparan sulfate and keratan sulfate
What are the three types of cartilage?
Hyaline, elastic and fibrous
Describe the structure and location of hyaline within the body?
Structure: composed of chondrocytes surrounded by a matrix of Type II collagen and proteoglycans; avascular and surrounded by perichondrium

Locations: skeleton of embryo, articular cartilage and cartilage of respiratory tract
Describe the structure and location of elastic cartilage in the body?
Structure: chondrocytes surrounded by matrix of Type II collagen and proteoglycans and elastic fibers; avascular, surrounded by perichondrium

Locations: external ear and epiglottis
Describe the structure and location of fibrous cartilage in the body?
Structure: chondrocytes surrounded by matrix of Type I collagen (similar to dense fibrous connective tissue), no perichondrium

Locations: intervertebral disks, menisci of knee, pubic symphysis
Describe gross anatomy of bone, what are the two types?
Cortical bone: thick, dense layer of calcified tissue makes up outer later, responsible for support/protection; very little turnover

Trabecular/Cancellous bone: thin, lattice-like tissue inside ends of both long and flat bones, actively involved in homeostatic function of bone (hematopoietic red marrow); high turn over
What is the bone matrix composed of?
Organic matrix (osteoid): provides elasticity/flexibilty and is composed of mostly Type I collagen, with some glycoproteins/proteoglycans.

Inorganic matrix (bone mineral): provides strength/rigidity, made of hydroxyapatite associated by collagen fibrils, which is involved in ion exchange with extracellular fluids.
What are the four types of bone cells?
Osteoblast, osteoclasts, osteocytes and osteoprogenitor cells.
Describe the function of osteoblasts.
Involved in the formation of new bone, using osteocalcin and Type I collage propeptides

Two phases:
Primary/woven bone: newly formed, unorganized collagen fibers, low mineral (hydroxyapatite) content
Secondary/lamellar bone: established bone, highly organized collagen fibers, high mineral content
Describe the function of an osteocyte.
Bone cells that are surrounded by matrix in lamellar bone and form 3-dimensional functional syncytium within matrix; respond to tensional forces and release factors that stimulate bone remodeling; periosteocytic space lies between osteocyte and wall of canaliculi, and contains ~1.3L of extracellular fluid and is important in calcium exchange from bone to blood
Describe the function of an osteoclast.
Stimulated by PTH attached to osteoblast, osteoclasts bind together to create a multi-nucleated cell that actively pumps out H+ to create a low pH environment in which enzymes can degraded bone
What are the stages of repair for a bone fracture?
1. Inflammatory/reactive phase (1-7 days): periosteal proliferation, hematoma and formation of granulation tissue around fractured ends
2. Reparative phase (2-12 wks): replacement of granulation tissue by hyaline cartilage (soft callus) in early stages, then degradation and replacement of soft callus with primary/woven bone (hard callus) in late stages
3. Remodeling phase (months to years): remodeling of primary to secondary, original contours of bone established
How does bone play a role in calcium homeostatis when there is low plasma calcium?
What role does bone play in calcium homeostatiss when there is high plasma calcium?
What is the role of bone in calcium homeostasis?
The skeleton contains 99% of total body calcium (hydroxyapatite) and appropriate levels of calcium are necessary for normal body function. Bone can mobilize calcium rapidly through the constant exchange of calcium from hydroxyapatite to interstitial fluids of bone or slowly, depending on bone resorption stimulated by hormones and cytokines.
What are the four events of the first week of development?
1. Fertilization: sperm penetrates corona radiata (follicle cells), binds and penetrates zona pellicida (shell) and sperm/oocyte membranes fuse; occurs in ampulla of uterine tube
2. Cleavage: series of mitotic divisions of zygote, with resulting cells called blastomeres, which are totipotent up to 4/8-cell stage; this takes 3-4 days, eventually reaching uterus as morula (16-32 cell)
3. Blastocyst formation: morula is compacted and a cavitation is formed, creating the blastocyst, which contains an embryoblast (inner cell mass), which is pleuripotent (stem cells) and trophoblast (outer cell mass); this occurs around 4.5-5 days
4. Implanation: blastocyst hatches from zona pellucida (which degenerates) by day 5 and implants in uterine wall, using trophoblast, by day 6-7
What are the events of the second week of development?
Two layers and Two cavities:
1. Trophoblast differentiates into two layers: inner cytotrophoblast and outer syncytiotrophoblast (many nuclei, one cytoplasm)
2. Embryoblast differentiateds into two layers: Hypoblast, which are cuboidal cells adjacent to blastocyst cavity, forming primitive yolk sac (exocoelomic cavity) and epiblast, columnar cells that secrete fluid to form Amniotic Cavity
3. Two cavities: bilaminar embryo is embedded in endometrial stroma by day 12, with trophoblast forming lacunae that connect to sinusoids in stroma; hypoblast cells form extraembryonic mesoderm, which develops cavities and forms the chorionic cavity (chorion secretes hCG to maintain corpus luteum for first 60 days of pregnancy)
What are the events of the third week?
Formation of the Trilaminar embryo:
1. Gastrulation: establishes three germ layers and defines body axes; begins with formation of primitive streak, midline thickening of epiblast cells, and epiblast cells displace hypoblast to form endoderm, then epiblast cells migrate between hypoblast and epiblast to form mesoderm (migrating cells undergo epithelial to mesenchymal transition, EMT)
------primitive groove is depression of streak
------primitive node is at caudal end, center is primitive pit
Epiblast cells migrate cranially, laterally and along midline, and after migration, remaining epiblast is called ectoderm
What is the ectodermal germ layer and what are its derivatives?
Outer most layer, from remaining epiblast cells

Derivatives: Central ns., Peripheral ns., Epidermis, Hair/Nails, Sensory epithelium of nose, ear, eye

Notochord induces formation of CNS and cells from CNS break off and form PNS
What is the mesodermal germ layer and what are its derivatives?
Middle germ layer is divided in to three layers:
1. Paraxial mesoderm (somite): vertebral column, muscle and skin
2. Intermediate mesoderm: components of urogenital system
3. Lateral plate of mesoderm: body wall (somatic mesoderm), wall of gut (splanchnic mesoderm) and limbs
What is the endodermal germ layer and what are its derivatives?
Bottom layer created by original migrating epiblasts

Derivatives: epithelium of gut and its derivatives, epithelium of respiratory system
Describe embryonic inductive tissue interactions.
It is the stimulation of a specific developmental pathway in one group of cells (responding tissue) by a closely approximated second group of cells (inducing tissue); this can occur through diffusion of inducer molecules between cells, through the contact of ECM between cells, or by direct contact of cells by gap junctions
Give an example of embryonic induction.
The optic cup (inducing) in the brain stimulates the formation of a lense (responding)
What is the period of highest susceptibility to developmental disorders occuring?
Occur during weeks 3-8, during the development of organs.
What are the main causes of development disorders and what are their mechanism?
Most causes are unknown, some are chromosomal defects, some are environmental factors and others are multifactorial.

Possible mechanisms: faulty tissue interaction, absence of normal cell death, failure of tube formation, failure of migration, developmental arrest
What is the collateral circulation around the shoulder?
Thyrocervial trunk > tranverse cervical artery > circumflex scapular artery > subscapular artery > axillary artery

Thyrocervical trunk > suprascapular artery > circumflex scapular artery > subscapular artery > axillary artery
What is the collateral circulation around the elbow?
Superior ulnar collateral artery > posterior ulnar recurrent artery

Inferior ulnar collateral artery > anterior ulnar recurrent artery

Middle collateral artery > recurrent interosseous artery

Radial collateral artery > recurrent radial artery
What is the collateral circulation in the hand?
Superficial palmar arch > deep palmar arch
Describe the normal cutaneous innervation of the arm and forearm (5 keys areas).
---Axillary: touch at the deltoid insertion
---Musculocutaneous: touch along the lateral forearm
---Ulnar: touch the ulnar side of hand
---Median: touch on the radial side of palm of hand
---Radial: touch the posterior side of thumb
Describe collagen biosynthesis.
Starts inside cell (nucleus): formation of mRNA for each type of α chain, then procollagen is synthesized by propeptides at both ends
---post-translational factors: hydroxylation (Vit C dependent), attachment of sugars to hydroxylysyl residues
---procollagen molecules assembled into triple helix
---vesicles transport to Golgi complex, where procollagen is packaged in secretory vesicles and then transported outside cell

---N-propeptidase/C-propeptidase cleave nonhelical terminal peptides forming insoluble collagen molecules that then form fibrils
---fibrillar structure reinforced by formation of cross-links between collagen molecules by lysyl oxidase