sensory corpuscles, peripheral nerves, and neurotransmitters Flashcards Preview

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Flashcards in sensory corpuscles, peripheral nerves, and neurotransmitters Deck (15):
1

Free nerve endings: description, location, and senses

C fibers: slow, unmyelinated fibers
Adelta: fast, myelinated fibers
found in all skin, epidermis, and some viscera
mediates pain and temp

2

Meissner corpuscles: description, location, and senses

large myelinated fibers that adapt quickly
found in glabrous (hairless) skin
sense dynamic, fine/light touch, and position sense

3

Pacinian corpuscles: description, location, and senses

large myelinated fibers that adapt quickly
found in deep skin layers, ligaments, and joints
good at vibration and pressure

4

Merkel discs: descripion, location, senses

large myelinated fibers that adapt slowly
found in the basal epidermal layer and hair follicles
sense pressure, deep static touch, and position sense

5

What is the structure of a peripheral nerve?

endoneurium: single neurve fiber layers
perineurium: permeability barrier that surrounds a fascicle of nerve fibers and must be rejoined in microsurgery for limb reattachment
epineurium: dense CT that surrounds the entire nerve

6

Norepinephrine: where is it synthesized and what are changes in disease?

made in the locus ceruleus
increased in anxiety and decr. in depression

7

dopamine: where is it synthesized, and what are the changes in disease?

made in the ventral tegmentum and the SNc (substantia nigra compacta)
incr. in Huntington and decr. in Parkinson and depression

8

Serotonin: synthesis location and disease

synthesized in the Raphe nucleus of the pons, medulla, and midbrain
incr. in Parkinson but decr. in anxiety and depression

9

ACh: location of synthesis and change in disease

made in the basal nucleus of Meynert
incr. in PD, decr. in Alzheimer and Huntingtons

10

GABA: location of synthesis and change in disease

made in the nucleus accumbens. nucleus accumbens also important for reward, pleasure, addiction, and fear.
decr. in anxiety and in huntington disease.

11

What structures form the blood brain barrier?

tight junctions btw the nonfenestrated capillary endothelial cells, a tight basement membrane, and astrocyte foot processes

12

How do glucose, amino acids, and lipid soluable products cross the BBB?

glucose and aa cross slowly via carrier-mediated transport
lipid soluable substances cross rapidly via diffusion

13

What are areas of the brain withOUT a BBB? What makes them unique?

unique bc of fenestrated capillaries
example: area postrema, which causes vomiting after chemo; OVLT, which is a circumventricular organ that is important for osmotic sensing.
pineal gland (secretes melatonin)
The neurohypophysis also has no BBB- it is open to allow neurosecretory products to enter circulation

14

What are other areas of the body with high notable barriers?

blood-testis barrier and maternal fetal blood barrier of the placenta.

15

How can infarction or neoplasm change the BBB?

infarction and neoplasm destroys the endothelial tight junctions and causes vasogenic edema.

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