Exam 2: Brainstem and Cerebellum Flashcards Preview

Anatomy A-215 > Exam 2: Brainstem and Cerebellum > Flashcards

Flashcards in Exam 2: Brainstem and Cerebellum Deck (25):
1

Brainstem

-consists of mesencephalon (midbrain), pons, medulla oblongata
-relay center for sensory input and motor output
-also responsible for many basic reflex actions

2

Pyramids

-bilateral ridges on anterior (ventral) side of medulla oblongata
-motor axons
-most of these axons desussate (cross over to opposite side)
-so in most instances each side of brain controls opposite side of body

3

Autonomic Nervous System Centers (part of what)

-part of medulla oblongata
-cardiac center: regulates heart rate
-vasomotor center: constricts and dialates arterioles so it regulates bp (constrict=increased bp, dialate=decreased bp)
-respiratory center: regulates breathing rate
-other centers

4

Inferior Part of 4th Ventricle

-space inside medulla oblongata

5

Pons

-chiefly composed of groups of axons (nerve fiber tracts)
-middle portion of brainstem

6

Respiratory Centers

-in pons help to control rate and depth of breathing

7

Superior Part of Fourth Ventricle

-part of pons
-continuous with cerebral aqueduct

8

Tectal Plate

-on posterior side of mesencephalon
-divided into superior colliculi and inferior collicui

9

Superior Colliculi

-(2) visual reflex centers
-coordinate head and eye movements to sudden image

10

Inferior Colliculi

-(2) auditory reflex centers
-coordinate head and eye movements to sudden sound

11

Cerebral Peduncles

-part of mesencephalon
-groups of axons (nerve fiber tracts) on anterior side of mesencephalon
-conduct nerve impulses between cerebrum and brainstem

12

Cerebellum

-right and left cerebellar hemispheres
-not part of brainstem
-higher motor and sensory functions

13

Cerebral (Mesencephalic) Aqueduct

-connects 4th ventricle to 3rd ventricle

14

Cerebellar Peduncles Definition

-groups of axons (nerve fiber tracts)

15

Inferior Cerebellar Peduncle

-connect medulla oblongata to cerebellum

16

Middle Cerebellar Peduncle

-connect pons to cerebellum

17

Superior Cerebellar Peduncle

-connect midbrain to cerebellum

18

Functions of Cerebellum

-coordinates and fine tunes skeletal muscle movement (cerebrum initates the movement, but the cerebellum makes it pretty)
-maintains balance and posture in response to info from proprioceptors (sensory nerve endings in muscles, joints, and tendons)
-DOES NOT START SKELETAL MUSCLE MOVEMENT

19

Cranial Meninges

-Pia Mater
-Subarachnoid space
-Arachnoid matter
-Dura Mater-outermost layer
-Inner Meningeal Layer
-Outer periosteallayer
-(in order from deepest to most superficial)
-in some areas the layers are separated and form dural venous sinuses

20

Dural Venous Sinuses

-large veins that drain blood away from vein
-between inner menigeal and outer periosteal layers of dura mater
-vein walls formed from dura mater

21

CSF

-cerebrospinal fluid
-provides buoyency for brain and spinal cord
-maintains CNS chemical environment
-produced continuously (approx 500 mL/day)

22

Ventricular System Consists of

-1 & 2) left and right lateral ventricles: found in each cerebral hemisphere
-3) third ventricle: space in diencephalon connects to each lateral ventricle via an interventricular foramen
-4) cerebral aqueduct: in mesencephalon
-5) fourth ventricle: in pons and medulla oblongata.
-(CSF flows from 1-5)

23

CSF Circulation Process

-CSF produed by choroid plexus in ventricles
-CSF flows from third ventricle to cerebral aqueduct to 4th ventricle
-CSF leaves 4th ventricle and enters subarachnoid space
-CSF circulates in subarachnoid space
-Excess CSF removed from subarachnoid space by arachnoid villi
-Pressure in subarachnoid space opens 'flap' in a villus so excess CSF leaves the subarachnoid space and enters dural venus sinuses (bloodstream)

24

Arachnoid Villi

-extensions of arachnoid mater that project int dural venous sinus

25

Hydrocephalus

-CSF production begins to exceed its removal or drainage at arachnoid villi
-'water on the brain'
-head becomes enlarged in young child
-fluid buildup can compress brain unless a medical shunt is put in.