Chapter 14 - Brain & Cranial Nerves Flashcards Preview

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Flashcards in Chapter 14 - Brain & Cranial Nerves Deck (59)
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1

Development of brain

Three to four-week embryo:

forebrain (prosencephalon) 

midbrain (mesencephalon)

hindbrain (rhombencephalon) 

2

Development of Brain 

5-week embryo

 

 telencephalon (cerebrum)

diencephalon (thalamushypothalamus & epithalamus)

mesencephalon (midbrain)

metencephalon (pons & cerebellum)

myelencephalon (medulla oblongata).

3

Forebrain 

Midbrain 

Hindbrain

Forebrain - Cerebrum & Diecephalon (3) 

Midbrain & cebral aqueduct

Hindbrain - pons & cerebellum + medulla

4

Brain stem

consists of?

 

continuation of spinal cord

consists of medulla oblongato, pons & midbrain

5

second largest part of the brain. 

posterior to brain stem 

 

Cerebellum

 

6

Diencephalon 

superior to brain stem

gives rise to thalamus, hypothalamus & epithalamus

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largest part of brain

cerebrum

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cranial meninges

dura mater - 2 layers (perieosteal & meningeal)

arachnoid mater

pia mater

 

9

(3) extensions of the dura mater separate parts of the brain: 

 

1) falx cerebri - seperate the 2 cerebral hemispheres

2) falx cerebelli - seperate the 2 cerebellar hemispheres

3) tentorium cerebelli - seperate cerebrum from cerebellum

10

Extensions of the Dura Mater: Brain Blood Flow and the Blood-Brain Barrier

Brain receives approximately _____% of the total blood supply. 
 Internal __ & __ arteries carry blood to brain. 
 Internal _____veins return blood from the brain. 

Blood-brain barrier (BBB) protects brain from?

 

20% 

internal carotid & vertebral arteries - blood to brain

internal jugular veins return blood from brain

 harmful substances. 

11

Cerebrospinal Fluid (CSF) 

clear, colourless fluid that protects CNS from chemical & physical injuries, absorbs shock, helps transport nutrients & wastes from blood & nervous tissue

 

circulates through cavities in brain (ventricles) & spinal cord (central canal) & in subarachnoid space

12

Ventricles

(3) & cerebral aqueduct

CSF-filled cavities within the brain. 

 1 lateral ventricles - in each hemisphere seperated byb septum pellucidum

third ventricle - along midline superior to hypothalamus

cerebral aqueduct - midbrain

fourth ventricle - between brain stem & cerebellum 

 

13

CSF formation & circulation

formed in choroid plexuses of lateral ventricles → interventricular foramina → third ventricle → cerebral aqueduct (midbrain)→ 4rth ventricle → median aperture/lateral apertures (2) → subarachnoid space →central canal 

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Choroid plexus

 

networks of capillaries in the walls of the 
ventricles. 

 

15

Ventricles are lined by __ cells

ependymal 

plasma is drawn from choroid plexuses through ependymal cells into ventricles to produce CSF

16

CSF is reabsorbed into blood by?

arachnoid villi - extensions of arachnoid that project into dural venous sinuses (sugerior sagittal sinnus)

17

Brain Stem (medulla, pons & midbrain) and Reticular Formation 

 

Medulla Oblongata

continous with superior spinal cord

white matter tract contains all sensory & motor tracts between spinal cord & other parts of brain 

white matter bulges on anterior - pyramids formed by large corticospinal tracts that pass from cerebrum to spinal cord

- common site of decussation of tracts - crossing over 

18

Centers of the Medulla Oblongata 

 

Vital centers: 

cardiovascular 

respiratory 

also includes centers for vomiting, swallowing, sneezing, coughing and hiccupping. 

houses 5 pairs of cranial nerves (VIII-XII) 

portion of 3rd ventricle found here

 

19

Midbrain (mesencephalon) 

Extends from the pons to the diencephalon. 
 Part of the ventricle found here- cerebral aqueduct - connects 3rd & 4rth ventricle

anterior part contains cerebral peduncles 

posterior part - tectum 

superior colliculli, inferior colliculi & substantia nigra

20

Cerebral Peduncles - paired bundles of axons in anterior part of midbrain 

consists of?

Tectum 

axons of the corticospinal, corticopontine and 
corticobulbar tracts. 

Tectum- situated posteriorly and contains 4 rounded elevations: 2
superior ones called superior colliculi and 2 inferior ones called inferior colliculi

 

21

Midbrain: 

Substantia Nigra

large area with dark pigments. Help control subconscious muscle activities.

Loss of neurons here is associated with Parkinson disease. 

 

 

22

Redc Nucleus of Midbrain

: Help control voluntary movements of the limbs

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Midbrain contains cranial nerves....

III-IV

24

Reticular Formation

Extends from upper part of spinal cord, throughout brain stem & into 
lower part of diencephalon.

25

Part of the reticular formation called the Reticular activating System (RAS) consists of?

 consists of sensory axons that project to the cerebral cortex

S helps maintain consciousness. 

 

26

Cerebellum 

vermis

anterior & posterior lobes

flocculonodular lobe

cerebellar cortex

arbor vitae

 

2nd largest part of brain

central constricted area = vermis

anterior and posterior lobes control subconscious aspects of skeletal movement. 

flocculonodular lobe - equilibrium & balance

cerebellar cortex - gray matter in form of parallel folds called folia

arbor vitae - tracts of white matter 

 

 

 

27

Cerebellar peduncles 

3 pairs - superior, middle & inferior 

attach cerebellum to brain stem 

functions: coordinate movements, regulate posture & balance 

28

Thalamus 

intermediate  mass joins right & left sides of thalamus

(7) major nuclei: anterior, medial, lateral, ventral, intralaminar, midline, reticular

major relay station for most impulse reaching primary sensory areas

transmits info from cerebellum & basal nuclei to primary motor area

29

Hypothalamus

inferior to thalamus 

consists of mammillary body, median eminence, infundibulum, and # of nuclei. 

 

30

Functions of the Hypothalamus

Control of the ANS

production of hormones 

regulation of emotion & behavioral patterns, eating & drinking, body temp, circadian rhythms