Structure and Function Week #4

Question 1

what is laboratory medicine

Answer 1

Practices for the assessment, diagnosis, treatment, management or prevention of health-related conditions

Question 2

why is screening important

Answer 2

to check for “occult” or hidden diseases in asymptomatic people.. examples- pap smear, HIV, TB, PKU, etc. Classifies people as likely or unlikely to have the disease. Goal: reduce mortality and morbidity

Question 3

what is a sequence of developments form earliest pathological change to resolution or death

Answer 3

natural history or progression of disease

Question 4

What is a case where early detection is not useful?

Answer 4

Cervical cancer- HPV can cause some changes to cervical cells that will if left alone regress.

Question 5

What are the four requirements for a screening program?

Answer 5

1) suitable disease 2) suitable test 3) suitable program (reaches target audience) 4) Good use of resources-cost, benefit

Question 6

What is difference between reliable and valid?

Answer 6

reliable is if you get the same results each time (test is repeatable) may or may not be valid
valid is if you get the correct result

Question 7

what is sensitivity

Answer 7

correctly classifies cases cases found/all cases

percentage of people with the disease who have positive test results

Question 8

what is specificity

Answer 8

correctly classifies non-cases.. non cases/all non-cases

percentage of individuals without the disease who have a negative test result

Question 9

what is predicitive value

Answer 9

probability that those tested are correctly classified PPV= true positives/all positives NPV- true negatives/all negatives

Question 10

reference ranges

Answer 10

established range of normal values in healthy people and anything out of range should be examined. they are not perfect as there may be small amount of people with normal results with undetectable disease, the sample size to calculate reference may have been small, population may not be representative, normal ranges vary

Question 11

what is the most common source of invalid results

Answer 11

pre-analytical errors

Question 12

What causes lack of regeneration in axons?

Answer 12

absence of schwann cell tubes, basal lamina and laminin. Need these components to repair axon.

dislocation of distal axon

Question 13

What contributes to slow regeneration of axons?

Answer 13

1) exposure to growth inhibiting extracellular matrix (chrondotin sulfate, proteglycans)
2) insufficient clearing of debris blocks regrowth

Question 14

What is a positive neuropathy symptom

Answer 14

tingling, paraesthisa, has feeling but feels different or pain

Question 15

what is a negative neuropathy symptom

Answer 15

no feeling at all, numbness

Question 16

What are the main causes of neuropathy?

Answer 16

axonal injury
demylination- causes change in conduction and message
diabetic neuropathy- starts with vascular pathology

Question 17

What is the basal lamina and where does it come from?

Answer 17

secreted by schwann cells and is the interface between the schwann cell and the endoneurium layer of connective tissue. the basal lamina is important because it contains laminin and fibronectin needed for regeneration of axons

Question 18

What is a fasicle?

Answer 18

it is a bundle of related axons, separate out as individual nerves to either muscle or skin. is surrounded by perineurium and multiple fasicles are wrapped together by epineurium.

Question 19

What is the contents of a peripheral nerve?

Answer 19

sensory neurons (info to CNS), motor neurons (to skeletal muscle) and sympathetic neurons (pre-ganglionic CNS-ganglion) (post-ganglionic ganglion to organ)

Question 20

What is a ganglion

Answer 20

cluster of nerve bodies in PNS

Question 21

What is a dendrite

Answer 21

tapering processes that arise from cell body, receives messages from receptors

Question 22

what is an axon

Answer 22

long thin extension of nerve cell that projects to different regions

Question 23

What are schwann cells

Answer 23

they are glia cells that surround axons in PNS. can be myelinated or unmyleinated. If myleinated form around single segment. Gaps in between or called nodes of ranvier

Question 24

what are the 3 layers of connective tissue around nerves

Answer 24

endoneurium- 1st layer surrounding axon, has capillaries to feed axon.
perineurium- wraps around fasicles
epineurium- wraps multiple fasicles together

Question 25

Nervi nervourm

Answer 25

nerves that innervate nerves

Question 26

vasa nervorum

Answer 26

blood vessels that supply nerves

Question 27

nerve trunk pain

Answer 27

pain resulting from damaging nerve itself ( the nervi nervorum)

Question 28

dysesthetic pain

Answer 28

burning, tingling along nerve`

Question 29

What is the ventral and dorsal horn

Answer 29

gray matter in spinal cord

ventral=anterior, dorsal= posterior

Question 30

what is the dorsal and ventral root

Answer 30

extends from dorsal and ventral horns- come together to form spinal nerve

Question 31

What is the dorsal rami

Answer 31

spinal nerve splits innervates back muscles and skin

Question 32

what is the ventral rami

Answer 32

spinal nerve splits and innervates the remaining muscles and skin

Question 33

How is a sensory nerve different

Answer 33

carries info to CNS, contains afferent nerve fibers, link sensory receptors in skin or tissue to relevant area of CNS. Cell bodies reside in dorsal root ganglia next to spinal cord. axon works in both directions to receptor and spinal cord

Question 34

what is the dorsal root ganglia?

Answer 34

formed by cell bodies of the sensory neurons, pseudo-unipolar with central and peripheral brances

Question 35

what are sympathetic ganglia

Answer 35

perpendicular to peripheral nerves, runs along vertebrae. works with pre and post gaglionic symptathitc nerves

Question 36

what is pre-ganglionic

Answer 36

connects CNS to ganglion, cell body in intermediolateral column in spinal cord. Projects axon to ganglia

Question 37

what is post-ganglionic

Answer 37

ganglion to organ, cell body in sympathic ganglia, projects to periphery