Exam 2: Brainstem and Cerebellum

Question 1

Brainstem

Answer 1

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

Question 2

Pyramids

Answer 2

• 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

Question 3

Autonomic Nervous System Centers (part of what)

Answer 3

• 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

Question 4

Inferior Part of 4th Ventricle

Answer 4

-space inside medulla oblongata

Question 5

Pons

Answer 5

• chiefly composed of groups of axons (nerve fiber tracts)

- middle portion of brainstem

Question 6

Respiratory Centers

Answer 6

-in pons help to control rate and depth of breathing

Question 7

Superior Part of Fourth Ventricle

Answer 7

• part of pons

- continuous with cerebral aqueduct

Question 8

Tectal Plate

Answer 8

• on posterior side of mesencephalon

- divided into superior colliculi and inferior collicui

Question 9

Superior Colliculi

Answer 9

• (2) visual reflex centers

- coordinate head and eye movements to sudden image

Question 10

Inferior Colliculi

Answer 10

• (2) auditory reflex centers

- coordinate head and eye movements to sudden sound

Question 11

Cerebral Peduncles

Answer 11

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

Question 12

Cerebellum

Answer 12

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

Question 13

Cerebral (Mesencephalic) Aqueduct

Answer 13

-connects 4th ventricle to 3rd ventricle

Question 14

Cerebellar Peduncles Definition

Answer 14

-groups of axons (nerve fiber tracts)

Question 15

Inferior Cerebellar Peduncle

Answer 15

-connect medulla oblongata to cerebellum

Question 16

Middle Cerebellar Peduncle

Answer 16

-connect pons to cerebellum

Question 17

Superior Cerebellar Peduncle

Answer 17

-connect midbrain to cerebellum

Question 18

Functions of Cerebellum

Answer 18

• 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

Question 19

Cranial Meninges

Answer 19

• 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

Question 20

Dural Venous Sinuses

Answer 20

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

Question 21

CSF

Answer 21

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

Question 22

Ventricular System Consists of

Answer 22

• 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)

Question 23

CSF Circulation Process

Answer 23

• 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)

Question 24

Arachnoid Villi

Answer 24

-extensions of arachnoid mater that project int dural venous sinus

Question 25

Hydrocephalus

Answer 25

• 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.