Flashcards in Case 2 Deck (24):
What are the four curvatures of the spine?
2 primary concave, 2 secondary convex anteriorly, the primary develop in the fetus, of the secondary the cervical curvature occurs with holding of the head ad the lumber develops during weight bearing in walking
What are the 3 most common abnormal curvatures?
Kyphosis, Lordosis ad Scoliosis
What is Kyphosis ad what causes it?
Exaggerated curvature of upper thoracic column. It is caused by bad posture, nutritional deficiencies or abnormal development of the spine.
What is Lordosis and what causes it?
Exaggerated convex curvature of lumbar spine. Caused by tight low back muscles, pregnancy or excessive visceral fat.
What is Scoliosis ad what causes it?
Abnormal lateral curvature (S-shaped spine). Cause can be congenital, due to abnormalities at birth or idiopathic.
Outline the characteristics of a cervical vertebrae
Small, rectangular body, large triangular foramen, bifid spinous process, smallest vertebrae with greatest rage of movement.
Outline the characteristics of a thoracic vertebrae.
Heart-shaped, large bodies, circular vertebral foramen, long, inferiorly sloping spinous process, long strong spinous process.
Outline the characteristics of lumbar vertebrae
Massive, kidney shaped body, triangular foramen, short, broad spinous process.
After notocord development, what three solid rods of cells develop from the mesoderm?
Paraxial mesoderm, intermediate mesoderm ad lateral plate mesoderm. They run parallel to the notocord.
Which rod of mesoderm forms the somites?
What are the three regions of somites, and what does each region develop into?
Portion nearest notocord and neural tube differentiates intosclertome which will form bone, cartilage, tendons, ligamnets, annulus fibrosus, connective tissue and meninges. The portion of somite nearest ectoderm differentiates into dermatome and becomes skin. The remaining portion differentiates into myotome which will go on to form deep back and neck muscles.
How do IV discs form from these?
The sclerotomal portion of each somite differentiates into two regions, anterior and posterior, some of the anterior cells migrate cranially to become the basis of IV discs. As the veretabral bodies, the notocord becomes extremely small in the vertebrae and larger in the IV discs, leading to it gelatinous centre, the nucleus pulposus. This is surrounded by circularly arranged fibers later that constitue the annulus fibrosus.
What are unencapsulated nerve endings and what do they mediate? Give an example.
Most abundant type of sensory nerve ending, they mediate painful and thermal sensations eg. Merkel endings.
What are encapsulated nerve endings and give an example?
Nerve endings surrounded by a stuctural specialisation of non-neural tissue, the nerve and surrounding tissue are commenly referred to as a corpuscles eg. Meissner's Corpuscles.
Noxious stimulation causes cells damage which causes the release of which chemical mediators?
K+, ATP and ADP, Bradykinin which is formed by circulating globulins with proteolytic enzymes, Histamine and Leukotriens from mast cells, Serotonin from platelts, Lactic acid due to ischemia and Prostaglandins.
Where does the spinomesencephalic tract project to?
Periaqueductal grey (PAG) and the superior colliculus.
What effects do projections to the PAG in the spinomesencephalic tract cause?
Sent to the posterior horn, they modulate pain at both NS and WDR neurons.
What do projections from the superior colliculaus through the spinomesencephalic tract cause?
Influence the movement of our eyes, directing our gaze to the site of injury.
Where does the spinoparabracial tract project to and what does it cause?
Parabracial nucleus, that then project to the hypothalamus and amygdala, these connections activate the pituitary-adrenal axis stress response, affects appetite and sleep and mediates fear learning.
What is encephalin and what are its two forms?
Penapeptide involved in regulating nocicption in the body. From the two forms one contains leucine (Leu-encephalin) and another contains methionine (Met-encephalin).
What is the definition of drug dependency?
Development of withdrawl symptoms when the substance is discontinued.
How does drug dependency develop?
Drugs increase the dopamine in the mesolimbic pathway dopaminergic system. This is a reward pathway that begins in the ventral tegmental area of the midbrain and connects to the nucleus accumbens. Increasing the level of dopamine in the NA mediates positive reinforcment of the drug.
How does tolerance occur?
receptors become less response to the drug stimulation, so more is needed to create the same effect.