CNS

Brain

Brain Regions

•Cerebral hemispheres•Diencephalon•Brain stem•Cerebellum

•Cerebral hemispheres

1. Cerebral Hemispheres

• Majority of brain• Called cerebrum • External appearance

– Gyri – elevated ridges– Sulcus – shallow grooves– Fissures – deep sulci that separate

brain regions

Gyrus

Sulcus

•Fissure (deep sulcus)

•Cerebral lobes are created by fissures

4 Lobes of Brain:

1. Parietal: interpret touch2. Temporal: auditory info3. Frontal: memory, judgment,

and logic4. Occipital: vision

Cerebral Gray Matter

•Gray matter = Cerebral cortex

Cerebral Gray Matter

•Consists of cell bodies of neurons

• FX: speech, memory, movement, sensation, consciousness

Cerebral White Matter

•White matter = Neuron fiber tracts (myelinated axons)

Cerebral White Matter

•Carries impulses to or from the cortex

Cerebral White Matter

•Corpus callosum = large fiber tract– Connects the hemispheres:L & R Brain

2. Diencephalon

• Connects the cerebrum to the brain stem– Thalamus– Epithalamus– Hypothalamus

Diencephalon

• Thalamus = Relay station for sensory nerves from spinal cord to cerebrum

Diencephalon

• Epithalamus = Pineal gland (melatonin)– induces sleep

Epithalamus

Diencephalon

• Hypothalamus = Hormone master gland– Connects to Pituitary-> - secretes hormones–Body temp, hunger, thirst, fatigue, sleep

3. Brain Stem

• Midbrain = connects Pons to Diencephalon

Brain Stem

• Pons = important in breathing

Brain Stem

• Medulla oblongata – Most inferior in stem– Merges with spinal cord– Helps regulate vital organ functions: heart rate, BP, & breathing

4. Cerebellum

• Compares the brain’s intentions with its performance

• Coordinating center for activity: – Movement– Balance– Coordination