Lab 1 + lecture 3 combined - The Human Brain and Cranial Nerves

Brain protection structures

Cranial bones

meninges

cerebrospinal fluid (CSF)

blood-brain barrier

Dura mater

Outermost meningeal layer; tough; attached to skull; has endosteal and meningeal layers

Arachnoid mater

Middle meningeal layer; web-like; contains subarachnoid space filled with CSF

Arachnoid villi

Structures that reabsorb CSF into venous blood (dural sinuses)

Pia mater

Innermost layer; thin; directly covers brain and spinal cord; contains blood vessels

Subdural space

Space between dura mater and arachnoid mater

Subarachnoid space

Space between arachnoid and pia mater; contains CSF

Cerebrospinal fluid (CSF)

Fluid that cushions brain; provides nourishment; maintains chemical environment

CSF production

Produced by choroid plexus in brain ventricles

CSF flow pathway

Lateral ventricles → → 3rd ventricle → → 4th ventricle → subarachnoid space → arachnoid villi → venous blood

Ventricles

Four fluid-filled chambers in brain that produce CSF

Cerebrum

Largest brain region; responsible for higher thinking memory and voluntary movement

Diencephalon

Includes thalamus and hypothalamus; involved in sensory relay and homeostasis

Brainstem

Midbrain pons and medulla; connects brain to spinal cord

Cerebellum

Coordinates movement of somatic functions: balance and motor learning, ex: playing piano

Cerebral cortex

Outer gray matter; 6-7 layers; center for higher intellect

Longitudinal fissure

Separates right and left hemispheres

Gyrus

Raised ridge of brain tissue

Sulcus

Shallow groove on brain surface

Corpus callosum

White matter tract connecting information between the two hemispheres

Fornix

Inferior portion of corpus callosum

Frontal lobe

Voluntary movement decision-making personality

Parietal lobe

Somatosensory processing touch pain temperature

Temporal lobe

Hearing language memory

Occipital lobe

Vision processing

Insula

Deep lobe involved in internal awareness

central sulcus

Separates frontal and parietal lobes

Lateral sulcus

Separates temporal lobe from frontal and parietal lobes

Primary cortex

Area that directly receives or sends signals (motor or sensory)

Parieto-occipital sulcus

Separates parietal and occipital lobes

Primary motor cortex (precentral gyrus)

controls voluntary movement (motor output)

Primary somatosensory cortex (postcentral gyrus)

Receives sensory input (touch, pain, temperature, proprioception)

Association cortex

Interprets and integrates information

Premotor cortex

Coordinates learned motor skills and sequences

Broca's area

Motor speech production

Wernicke's area

Language comprehension

Visual cortex

Processes visual input occipital lobe

Auditory cortex

Processes sound temporal lobe

Chemosensory Centers

Primary Olfactory (smell) and gustatory (taste)

Olfactory cortex

Smell; located in temporal lobe

Gustatory cortex

Taste; located in parietal lobe near postcentral gyrus

Thalamus

Major sensory relay (gateway to cerebral cortex - all senses except smell pass through here)

Hypothalamus

Maintains homeostasis regulates temperature hunger thirst hormones

Hypothalamus control

Controls pituitary gland and autonomic nervous system

Brainstem function

Contains nuclei for many cranial nerves; pathway between brain and spinal cord

Midbrain

Contains cerebral peduncles; relays motor and sensory signals

Pons

Relay station; connects cerebellum and cerebrum; contains cranial nerve nuclei

Medulla oblongata

Controls vital functions heart rate breathing digestion

Decussation

Crossing of motor fibers in medulla; right brain controls left side of body

Pyramids (medulla)

Motor tract crossover to other side of body (decussate)

Cerebellum function

Coordinates movement balance posture motor learning

Arbor vitae

Tree-like white matter in cerebellum

Vermis

Separates cerebellar hemispheres

Folia

Small folds of cerebellum

Cranial nerves

12 pairs; sensory motor or mixed; serve head and neck

mnemonic for cranial nerves NAMES

Oh Oh Oh To Touch And Feel Very Good Velvet AH

I - Olfactory

II - Optic

III - Oculomotor

IV - Trochlear

V - Trigeminal

VI - Abducens

VII - Facial

VIII - Vestibulocochlear

IX - Glossopharyngeal

X - Vagus

XI - Accessory

XII - Hypoglossal

mnemonic for cranial nerves FUNCTIONS

Some Say Marry Money, But My Brother Says Big Brains Matter More

S = Sensory

M = Motor

B = Both

Sensory cranial nerves

(bring info TO brain) I II VIII (olfactory, optic, Vestibulocochlear)

Motor cranial nerves

(send commands from brain) III IV VI XI XII (oculomotor, trochlear, abducens, accessory, hypoglossal)

Mixed cranial nerves

V, VII, IX, X (trigeminal, facial, glossopharyngeal, vagus)

Olfactory nerve (I)

Smell

Optic nerve

(II) Vision

Oculomotor nerve

(III) Eye movement and pupil constriction

Trochlear nerve

(IV) Eye movement superior oblique muscle

Trigeminal nerve

(V) Facial sensation and chewing

Abducens nerve

(VI) Lateral eye movement

Facial nerve

(VII) Facial expression and taste anterior 2/3 tongue

Vestibulocochlear nerve

(VIII) Hearing and balance

Glossopharyngeal nerve

(IX) Taste posterior 1/3 swallowing salivation gag reflex

Vagus nerve

(X) Major parasympathetic nerve; controls heart, lungs, digestive organs

Accessory nerve

(XI) Neck turning and shoulder shrugging

Hypoglossal nerve (XII)

(XII) Tongue movement speech and swallowing