UNIT 4 CHP 14 BRAIN & CRANIAL NERVES

dura mater

inner fibrous layer (meningeal layer), outer fibrous layer (endosteal layer), venous sinuses between 2 layers

arachnoid mater

covers brain, contacts epithelial layer of dura mater

subarachnoid mater

between arachnoid mater & pia mater / CSF

pia mater

attached to brain surface by astrocytes

cerebrospinal fluid (CSF)

surrounds all exposed surfaces of CNS, interchanges with interstitial fluid of brain

functions of CSF

1. cushions delicate neural structures

2. supports brain (floats brain)

3. transports nutrients, chemical messengers, and waste products

choroid plexus

specialized ependymal cells that secrete CSF into ventricles

lateral ventricles

each cerebral hemisphere contains 1 large lateral ventricle

third ventricle

ventricle of the diencephalon

cerebral (mesencephalic) aqueduct

connects with fourth ventricle via canal

fourth ventricle

extends into medulla oblongata, becomes continuous with central canal of the spinal cord

blood supply into the brain

internal carotid arteries & vertebral arteries

blood supply out of the brain

internal jugular veins

stroke or cerebrovascular accident (CVA)

shuts off blood portion of brain, neurons die

blood-brain barrier

isolates CNS neural tissue from general circulation

astrocytes

controls blood brain barrier by releasing chemicals that control permeability

medulla oblongata

allows brain & spinal cord to communicate

autonomic nuclei (reticular formation)

controls visceral activities

nucleus gracilis & nucleus cuneatus

somatic sensory to the thalamus

solitary nucleus

visceral sensory

olivary nuclei

somatic motor

cranial nerves of the medulla oblongata

VIII, IX, X, XI, XII

pons

links cerebellum with mesencephalon, diencephalon, cerebrum, and spinal cord

functions of the pons

1. respiration - apneustic center and pneumotaxic center modify respiratory center activity

2. sensory and motor nuclei of cranial nerves V, VI, VII, VIII

3. nuclei and tracts - process and relay information to and from cerebellum

corpora quadrigemina

superior and inferior colliculus

superior colliculus

visual

inferior colliculus

auditory

cerebral peduncles

contain descending fibers (motor) to cerebellum & ascending fibers (sensory) to thalamus

tegmentum

red nucleus & substantia nigra

red nucleus

many blood vessels, subconscious muscle tone

substantia nigra

pigmented gray matter, regulates basal nuclei, dopamine

cerebellum

an automatic processing center

functions of the cerebellum

1. adjusts the postural muscles

2. programs and fine tunes movements

folia

surface of cerebellum, highly folded neural cortex

the anterior and posterior lobes are separated by the

primary fissure

cerebellar hemispheres

left & right separated at midline

purkinje cells

found in cerebellar cortex (superficial layer)

arbor vitae

highly branched, internal white matter of cerebellum

cerebellar nucleus

embedded in arbor vitae, relay information to purkinje cells

superior cerebellar peduncles

to midbrain & cerebrum

middle cerebellar peduncles

to pons

inferior cerebellar peduncles

medulla oblongata & spinla cord

ataxia

disturbance in muscle coordination

diencephalon

integrates sensory information & motor commands

the pineal gland

secretes hormone melatonin

thalamus

filters ascending sensory information for primary sensory cortex & relays inforamtion between basal nuclei & cerebral cortex

intermediate mass

projection of gray matter that extends into 3rd ventricle from each side

anterior group

part of limbic system (emotions)

medial group

provides awareness of emotional states

ventral group

relays sensory information

lateral group

affects emotional states, integrates sensory information

pulvinar

sensory

lateral geniculate

visual

medial geniculate

auditory

mamillary bodies

process olfactory and other sensory information & controls reflex eating movements

infundibulum

a narrow stalk connects hypothalamus to pituitary gland

pituitary gland

major endocrine gland, connected to hypothalamus, interfaces nervous and endocrine system

functions of the hypothalamus

1. subconscious control of skeletal muscles

2. control autonomic function

3. coordination of nervous and endocrine systems

4. secretes hormones: ADH & oxytocin

5. produces drives like hunger & thirst

6. coordination of voluntary & autonomic

7. regulate body temperature

8. controls circadian rhythm (day-night cycles)