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Flashcards in Block 2 Deck (84):
1

bony encasement

-skull and vertebrae
-provides protection of the CNS from external injury

2

Meninges

-3 connective tissue layers
-provide mechanical suspension system anchored to bones to protect CNS from internal injury
-provide a space for CSF circulation

3

purposes of CSF

-provides buoyancy
-provides a source of nutrients and assists in waste removal

4

pia mater

-(delicate mother)
-thin membrane covering brain and spinal cord
-surface blood vessels travel just above it, and their capillaries penetrate the pia into the brain

5

arachnoid

-slightly thicker than pia matter
-is the middle layer
-does not follow surface contours, will bridge over major depressions
-since it bridges, it makes the subarachnoid space which is where the CSF will circulate

6

cisterns

enlargements of the subarachnoid space

7

subdural space

the minimal space between the dura and the arachnoid layers

8

dura matter

-much thicker than meningeal layers
-two parts: outer--> periosteal dura
inner--> meningeal dura

9

The sublayers of the dura matter are normally fused except at

sinus

10

sinuses

-CSF and venous blood drain into the sinuses

11

dural reflections

-the infolding and fusion of the meningeal layers of the dura
-this acts as a hammock-like suspension system

12

falx cerebri

keeps the two cerebral hemispheres frm impacting each other

13

what structure prevents the cortex from driving into the cerebellum or brainstem during blows to the head?

tentorium cerebelli

14

denticulate ligaments

attach layers of meningeal layers to each other

15

lateral ventricles

-backwards C shape of telencephalon

16

3rd ventricles

lie within the diencephalon

17

the cerebral aqueduct

within the mesencephalon

18

4th ventricle

-within the pons and medulla

19

choroid plexus

lies within the lateral, third, and fourth ventricles
-is where the CSF is produced

20

cappillaries in the choroid plexus are lined with ___ cells that are ____

-endothelial cells that are leaky

21

Blood pressure may force water solutes into the space between the capillary and choroid epithelium, but they wont pass into the ventricles why?

because the choroid epithelial cells are connected to each other by tight junctions

22

blood-cerebrospinal fluid barrier

-prevents solutes and water from entering into the ventricles

23

Is CSF a simple ultrafiltrant of blood ?

No. It is formed by actively transporting substances by carrier proteins in the choroid epithelium

24

describe the flow of CSF

-lateral-->third--> cerebral aqueduct--> fourth

25

How does CSF gain access to the subarachnoid space to supply the surface structures?

-the median aperture and the two lateral apertures

26

where is CSF collected for diagnostic purposes?

from cisterns, like the lumbar cistern

27

blockage of cerebral aqueducts or apertures can lead to

-hydrocephalus

28

Where do surface veins of the brain empty?

-the superior sagittal sinus which is along top of the falx cerebri---> transverse sinuses along the back of the tentorium cerebelli

29

Deep veins feed into the

-inferior sagittal sinus

30

where do all sinuses ultimately drain into?

internal jugular vein

31

what two major vessels supply the brain?

-paired internal carotid and the vertebral arteries

32

branches of the vertebral arteries

anterior spinal artery and the paired posterior spinal artery

33

basilar artery

-forms just below the pons as the vertebral arteries merge

34

branches of the basilar artery supplies

-the brainstem
-cerebellum
-choroid plexus of the fourth ventricle

35

the posterior cerebral artery

-supplies the occipital lobe, inferior temporal lobe, and parts of the diencephalon and midbrain

36

name the two major branches off of the internal carotid and one minor

-anterior cerebral artery
-middle cerebral artery
-minor: anterior choroidal artery

37

what does the anterior cerebral artery supply?

-anterior and medial cortical structures

38

the middle cerebral artery supplies

-most of the lateral cortical hemispheres and bulk of the basal ganglia

39

the minor anterior choroidal artery supplies

deeper parts of the basal ganglia, amygdala, and hippocampus and choroid plexus of lateral and 3rd

40

what joins the internal carotid and the vertebral artery systems at the base of the brain?

-posterior communicating arteries

41

Circle of Willis

provides potential redistribution of blood when one major artery is blocked... not so good with sudden blockages like in embolisms

42

name the 4 things the vestibular system can do

-relays signals to motorneurons that control posture, to help prevent loss of balance
-relay signals to extraocular motorneurons to aid in visual fixation during head movements
-provides for a sense of where self is in space , gives an implicit knowledge of up and down
-helps to provide for changes in changes in respiration and circulation that are necessary as we move and change posture

43

what composes the vestibular labrynth

3 semicircular canals and two otolith organs

44

what special kind of medium bathes the stereocilia

the endolymph

45

what does it mean that the vestibular afferents in VIII have a resting discharge

at rest, the stereocilia of the hair cells are unbent yet still releasing neurotransmitter

46

ampulla

swelling at the central end of each semicircular canal where the hair cells are confined

47

how are hair cells in the horizontal canal oriented in the ampulla?

kinocilia point to the utricle (the central end of each ampulla)

48

crista ampullaris

-the sensory epithelium within an ampulla

49

describe how the semicircular canals respond to the following head movements:
head rotation to the left

Left:
Lateral- increase
Superior- 0
Posterior- 0
Right:
lateral- decrease
Superior-0
Posterior-0

50

describe how the semicircular canals respond to the following head movements:
head rotation to the right

Left:
Lateral-decrease
superior-0
posterior-0
Right:
lateral-increase
superior-0
posterior- 0

51

describe how the semicircular canals respond to the following head movements:
Left ear down

Left:
lateral-0
superior- +
posterior- +

Right:
lateral-0
superior- -
posterior- -

52

describe how the semicircular canals respond to the following head movements:
right ear down

Left:
lateral- 0
superior- (-)
posterior-(-)
Right:
lateral- 0
superior- +
posterior- +

53

describe how the semicircular canals respond to the following head movements:
Pitch forward

Left:
Lateral-0
superior- (+)
posterior- (-)
Right:
lateral-0
superior- (+)
posterior- (-)

54

describe how the semicircular canals respond to the following head movements:
Pitch backwards

Left:
Lateral-0
superior- (-)
posterior- (+)
Right:
lateral-0
superior- (-)
posterior- (+)

55

what information is not coded by the semicircular canals, but by the otilith organs?

-info concerning static position of head in space (location with respect to gravity)
-information regarding linear accelerations placed on the head as occurs when falling or de/accelerating in a car

56

name the two otilith organs

utricle and sacculus

57

name the two important ways the utricle and sacculus differ from the semicircular canals

1-the stereocilia of the otilith organs are in the otilithic membrane which has a higher specific gravity than the surrounding fluid- its the membrane that shifts in position when tilted
2- the hair cells do not face in one direction! they are in many different orientations

58

hair cells in the utricular macula are affected by

-linear acceleration in the horizontal plane
tilting of head with respect to gravity

59

hair cells in saccular macula are affected by

-linear acceleration in the vertical plane
-tilting head with respect to gravity

60

the striola

the imaginary line where direction of hair cells reverse abruptly

61

most vestibular afferents project to one of 4 brainstem nuclei

the 4 brainstem nuclei are:
-superior
-inferior
-lateral (Deiter's nucleus)
-medial

62

some neurons in the vestibular nuclei lack neck inputs and fire during head and whole body type movements. Give an example

neurons that project to extraocular motorneurons

63

flocculus

-portion of the cerebellum that along with the medial cerebellum regulates activity of the vestibular nuclei

64

which vestibular nuclei have projections to the cranial nerve nuclei III, IV, and VI and why

-medial and superior nuclei
-these connections are responsible for powerful vestibulo-ocular reflexes

65

medial vestibulo-spinal tract (MVST)

-mainly influences neck motorneurons
-important for maintaining stable head position in space

66

lateral vestibulo-spinal tract

-involved in maintaining balance through its effects on limb motorneurons

67

direction of sound waves

large auricle (external ear)--> external auditory meatus--> tympanic membrane--> malleus, incus, and stapes

68

Eustachian tube

-connects the middle ear to the throat
-works to keep the pressure on the two sides of the ear drum equal

69

name the 3 fluid-filled chambers of the cochlea

-scala vestibuli
-scala tympani
-scala media

70

helicotrema

-where the two perilymph-filled chambers join at the apex of the cochlea

71

when sound causes the tympanic membrane and middle ear bones to vibrate, the force is transmitted to through the ____ into the ___. The necessary pressure release to allow fluid to vibrate is allowed by the ____

-oval window
-scala vestibuli
-round window

72

what and where are the sensory epithelia for the auditory system?

-organ of corti
-located in cochlear duct

73

Hair cells of organ of Corti are innervated by afferents of the ____ nerve. The cell bodies of these afferents are located in the ________, which is found in the bone just outside the cochlea

-cochlear nerve
-spiral ganglion

74

the stereocilia of auditory hair cells are imbedded in

tectorial membrane

75

the hair cells are attached to

the basilar membrane

76

____ send their axons through the VIII cranial nerve to innervate ___ hair cells

-neurons in the superior olivary mucleus
-outter

77

function of auditory outter hair cells

-to adjust sensitivity in the peripheral auditory system

78

If people lose hair cells, but retain innervation of the cochlea by the VIII nerve then ___ can be used ti restore hearing

-cochlear implants

79

parts of the cochlear implant

-microphone: detects sound
-speech processor: to determine which sound frequencies are present. Has a microprocessor to filter out noise
-transmitter and receiver/stimulator: that converts signals from sound processor to electrical pulses
-22 electrodes to go along the cochlea

80

name the two brainstem nuclei that the auditory afferents can terminate?

-dorsal cochlear nuclei
ventral column nuclei

81

projects directly to the inferior colliculus

dorsal cochlear nucleus

82

the dorsal cochlear nucleus projects directly to the inferior colliculus which projects to the ____ which projects to Brodmann's areas ____

-medial geniculate
-41 and 42

83

name the difference between the brain capillary endothelial cells and the choroid capillary endothelial clls

-the brain capillary endothelial cells have tight junction
-the choroid capillary endothelial cells do not have tight junctions ** its the choroid epithelial cells that have the tight junctions

84

Common features of ascending dorsal column and spinothalamic tract

-consist of 3 neurons in series
-mostly crossed
-somatotopically organized
-maintain modality specificity