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Semester 5 November > Histology > Flashcards

Flashcards in Histology Deck (51)
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Function of crista ampullaris

Detect rotation of head

1

4 components of crista ampullaris

Crista
Hair cells
Capula
Ampulla

2

Location of crista ampullaris

Semicircular canals

3

Adaption of basal laminate for tonotopic mapping

Base - thicker and closer for high frequency
Apex - thinner and further for low frequency

4

Function of macula

Detection of linear movement and gravity

5

Components of macula

Otoliths
Otolithic membrane
Hair cells
Supporting cells
Nerve endings

6

Types of nerve endings

Hair follicle ending
Ruffini ending
Krause corpuscle
Pacinian corpuscle
Meissners corpuscle
Free nerve endings

7

Fx ruffini ending

Pressure on skin
Dermis of hairy and glabrous skin

8

Fx pacinian corpuscle

Responds to vibration
Deep dermis

9

Fx meissners corpuscle

Responds to vibration
Found in glabrous skin

10

Fx free nerve endings

Pain, temp

11

Two parts of tympanic membrane

Pars tensa
Pars flaccida

12

Define process of Wallerian degeneration

Chromatolysis
Swelling of cell body
Degeneration of disconnected axon
Degeneration of myelin sheath
Macs and Schwann mop up

13

Outline role of Schwann cells in regeneration in PNS

Remove debris
Provide growth promoting substrate
Guide regenerating axon
Promote neuron survival = neurotrophic factors
Re-myelinate

14

Briefly explain how B amyloid fragment implicated in Alzheimer's

Direct toxicity to neurons causes:
Neuronal damage
Disruptions of synaptic contacts

Promotes glial reactivity and inflammatory respose which damages and kills neurons.

15

Three true barriers on BBB

Cerebral capillaries
Choroid plexus
Arachnoid mater

16

Why blind spot not perceived in field of vision

Visual centers extrapolate info from adjacent areas of visual field and 'fill' the space.

17

Two main functions of neuronal cytoskeleton

Cellular structure
Axonal transport

18

How do cells in CNS contribute to regeneration failure

Astrocytes - become reactive, form glial scar and express axon-growth inhibiting proteoglycans.
Oligodendrocytes - up regulate release of axon-growth inhibiting proteins.
Microglia - remove debris but can release cytotoxic agents.

19

Principle function of each support cell type in CNS

Astro - metabolic/structural support, BBB, regulate ECM
Oligodendrcytes - myelination, membrane protein channels
Microglia - immune defense
Ependyma - movement of CSF (?neurogenesis)

20

Types of sensory axons and nature of stimuli

Aa - proprioception
Abeta - mechanoception
Adelta - pain, temp
C - pain, temp, itch

21

Fast axonal transport uses what protein

Kinesin

22

Fx of pericyte in CNS

Structural stability
Phagocytosis
Vasodynamic capacity

23

Transport mechanisms across cerebral caps

Carries systems (highly specific) eg D glucose, amino acids
Receptor mediated endocytosis eg insulin
Diffusion

24

Structural differences between BMEC and normal endothelial cells

Absence of fenestrations
More extensive tight junctions

25

Functional differences between BMEC and normal endothelial cells

- impermeable to most substances
- space pinocytotic vesicular transport
- increased expression of transport and carrier proteins
- no gap junctions
- limited para cellular and trans cellular transport

26

What is the role of astrocyte foot process in the BBB?

- provide biochemical support
- influence organisation of vessel wall
-involved in postnatal maturation of BBB
- co-regulate function be secretion of soluble cytokines

27

Regions not enclosed by BBB

- area postrema
- median eminence
- neurohypophysis
- pineal gland
- subfornical organ
- lamina terminalis

28

Type of molecules that can cross the BBB

Hydrophobic (CO2, O2, N2)
Small polar (water, urea)

29

Type of molecules that can't cross the BBB

Large polar molecules (glucose, sucrose)
Ions