What are the three isoenzymes of creatine kinase?
- 1. CK-MB = heart muscle damage
- 2. CK-MM = skeletal muscle damage
- 3. CK-BB= brain damage
Osteoblasts from the bone matrix which is composed of what?
- Osteoid - nonmineralized
- Organic- Collagen I & V, proteoglycan, glycoproteins
- Inorganic- Ca2+ & phosphorous
What is an osteocyte?
- It is an osteoblast that has been trapped in the same matrix that it has created.
- Space occupied by osteocyte is called lacuna
- Connected via cannaliculi to gap junctions
What are the derivatives from which arise the smooth muscle of the gut tube, blood vessels, and eye?
Splanchnic mesoderm -> gut tube
Somatic mesoderm -> blood vessels
ectoderm -> eye
What abnormality in musculoskeletal development leads to the above presentation in an infant?
This is Prune belly syndrome which is a result of the lack of myotome migration.
What stimulates the somites to differentiate into sclerotome and dermomyotome?
Wnts & Shh
What is the general mechanism of endochondral ossification?
- The hyaline cartilage grows
- osteoblasts invade -> death of chondrocytes and calcification of matrix -> large marrow spaces
osteoblasts produce primary bone on top of the calcified cartilage.
Osteoclasts come and break down for formation of secondary bone.
What vitamins are necessary for bone?
Vitamin D -> Ca2+ absorption
Vitamin C -> collagen formation
Vitamin A -> proper bone formation
What is it composed of?
Is there perichondrium?
Where is it located?
- COMPOSED OF:
- - type II collagen, basophilic matrix, chondrocytes in isogenous groups.
PERICHONDRIUM: Present except on articular surfaces
- - articular ends of long bones, nose, larynx, trachea, bronchi, ventral ends of ribs, template for endochondral bone formation.
What is Genu varum and what causes it?
small Q angle which is caused by arthrosis of medial collateral ligament which will lead to stress on the Lateral collateral ligament.
What does the unhappy triad consist of?
- Anterior cruciate ligament
- Medial collateral ligament
- medial meniscus
The anterior cruciate ligament's function.
To prevent hyperextension of the knee.
Tested with the anterior drawer test or Lachman's test
What are the passive and dynamic components of the arch of the foot?
PASSIVE: bones, aponeurosis, plantar ligament, plantar calcaneocuboid ligament, plantar calcaneonavicular ligament.
- DYNAMIC: Intrinsic muscles, long tendons
- - Longitudinal- Flexor hallucis longus, Flexor digitorum longus
- - Transverse- Fibularis longus and Tibialis posterior
At what level is the Xiphoid process and what is it a landmark for?
- 10th vertebrae
- - inferior limit of thoracic cavity
- - Superior border of liver
- - Central tendon of diaphragm
- - inferior border of heart
- - esophagus into the diaphragm
What does the parietal pleura consist of?
- Costal pleura
- Cervical pleura (cupular pleura)
- mediastinal pleura
- Diaphragmatic pleura
What is the difference between the intercostals nerves and phrenic nerves in relation to the pleural of the lungs?
- Intercostals (T1-T11)
- - costal pleura and diaphragmatic pleura
- - pain is sensed to originate from chest wall
- Phrenic Nerves (C3,4,5)
- - Mediastinal and rest of diaphragmatic
- - pain is sensed to come from the neck +/or shoulder (referred)
What is the costomediastinal recess?
Potential pleura space where heart can touch posterior thoracic wall.
What is the triad of skeletal muscle?
- Terminal cisternae
- T tubules
- Terminal cisternae
What are the bands of skeletal muscle?
What is the action of skeletal muscle stimulation
Ap -> Ca influx -> Ach release -> sarcolemma deplolarization -> T tubules -> ca released from Sarcoplasmic reticulum -> cytosol troponin -> tropomyosin shift -> contraction
What are the NT responsible for the EPSP?
Glutamate and Acetylcholine -> Na+ in, Ca2+ in
Name the 2 receptors that Ach can bind to with regards to NMJ
Ionotropic - faster - Na influx
Metabotropic - slower - G protein - K efflux
What muscle type uses creatinine phosphate and glycolysis as its main source of energy?
- Fast Twitch glycolytic
- - fast fatigue
- - Fast velocity
- - large diameter
What are the components of tension of muscle in relation to length?
What determines the # of active muscle fibers
# of fibers per unit
# of active motor units
What are the 5 states of contraction in smooth muscle?
- partially contracted(tone)
- phasically active
What is the difference between single unit smooth muscle vs multi unit smooth muscle?
- Single unit has gap junctions and relies on 1 cell to produce the spontaneou AP to affect multiple cells.
- - small blood vessels, urinary, reproductive, GI tract
- Multi-unit involves specific innervation.
- - lung airways, blood vessels, eyes, hair follicles
What does MLCK and MLCP lead to
MLCK leads to contracted state
MLCP leads to uncontracted state
Where does the Spinal cord, dura mater, and filum terminale end?
- Spinal cord - L2
- Dura mater- S2
- Filum terminale - Coccyx 2
Layers encountered before you reach spinal cord with a stab from the back.
- ligamentum flavum
- posterior longitudinal ligament
- Dura mater
- Arachnoid mater
- Pia mater
Explain disc herniation
Posterior fibrous annulus is the most common site for disc herniation where gelatin from the nucleus pulposus can escape leading to a pinched nerve that passes through and ends at a lower level.
What are 2 contractile non-muscle cells?
Myoepithelial - glandular secretory units
Myofibroblast- decrease wound opening
What do smooth muscle lack?
T-tubules, sarcomeres, and troponin
Treatment for Myasthenia Gravis?
- azathioprine (immunosuppressive)
What should be avoided in a patient with myasthenia gravis?
- extreme temperatures
Damage to the radial nerve results in what?
- Wrist drop
- sensory loss of the lower part of the dorsal aspect of the thumb, and proximal dorsal aspect of all the fingers except for the little finger and half of the ring finger.
Describe the flexor digitorum longus?
Arises from the middle of the posterior tibia to the distal phalanges of 2-5.
- Flexes the toes and foot
- invert ankle
What is innervated by the obturator nerve?
Adductor longus, adductor brevis, anterior portion of the adductor magnus, and gracillis
Describe the lumbrical muscles
- Innervated by the ulnar nerve(3 and 4) and the median nerve (1 and 2)
- - extend fingers at the interphalangeal joints
Caused by deposition of monosodium urate crystals in the joints and soft tissue(tophi)
Aspiration of the joint shows negatively birefringent crystals, which are yellow in color when viewed parallel to the polarizer and blue when viewed perpendicular.
Casues: enzyme def, lifestyle, or drugs (chemotherapy)
What nerve is damaged with Charcot Marie Tooth disease?
- Deep peroneal nerve
- - supplies tibialis anterior, extensor hallucis, extensor digitorum, and peroneus tertius.
- - Action = dorsiflexion and digit extension.
What protects the subclavian vessels and brachial plexus in clavicle fractures?
Subclavius (occupies small groove on the undersurface of the clavicle)
What does C6 nerve root provide?
Wrist and elbow flexion, elbow extension, and arm abduction.
Sensory innervation of the palmar surface of the first 3 digits and over the deltoid.
What are the branches of the facial nerve on the lateral aspect of the face?
- Posterior auricular
- Marginal Mandibular
Please tell Ziggy Bob Marley called
If you want to anesthetize the median nerve at the wrist where you do this?
Between the palmaris longus tendon and the flexor carpi radialis tendon.
What cord does the ulnar nerve arise from?
The medial cord of the brachial plexus
What is steroid myopathy?
- Caused by exogenous corticosteroid use or Cushing disease.
- Chronically characterized by the insidious onset of muslce weakness of the thighs and upper arms.
- Preferential atrophy of type II fibers.
What is Pagets disease of the bone?
- Repetitive cycles of osteolysis and disorganized osteoblastic activity -> thickened bone with haphazard lamellar orientation.
- Affects skull and axial skeleton
- Histologic jigsaw puzzle appearance of bone llamellae is pathognomonic.
- Presentation = pain, bone deformities, and chalkstick fractures.
Describe the structure of dystrophin?
- Rod like structure with globular strcutres at end
- amino terminal end binds to actin filaments of myofibrils
- cysteine carboxy end binds to beta-dystoglycan (anchors complex to basal lamina via laminin.)
Describe osteogenesis imperfecta.
- Disorder of type I collagen synthesis
- multiple fractures in the absence of overt soft tissue damage
- blue tinged sclera present in some types of OI
How would Rickets present
bony changes to lower ends of the radius and ulna, where the diaphyseal ends become fuzzy, cup-shaped, and may develop a spotty rarefaction.
- deformity of chest wall
- bowing of legs
Where do the following muscles insert?
- Psoas major - lesser trochanter
- Gluteus maximus - gluteal tuberosity
- Gluteus medius, minimus, piriformis - greater trochanter