THE BRAIN

• The largest and most complex organ of the nervous system

• Oversees many aspects of physiology such as – Sensation and

perception– Movement – Thinking

THE BRAIN

• Thin membrane located between the bone and brain/spinal cord

• Protection

MENINGES

• 3 layers– Dura mater– Arachnoid mater– Pia mater

MENINGES

• Outermost layer• Tough, white connective tissue, blood vessels

and nerves• Continues into vertebral canal as it surrounds

the spinal cord

DURA MATER

• Middle layer• Thin, weblike membrane that does not have

blood vessels• Cerebrospinal fluid (CSF) located between

arachnoid mater and pia mater

ARACHNOID MATER

• Innermost layer• Many blood vessels• Attached to surface of brain

PIA MATER

• Cerebrum• Diencephelon• Cerebellum• Brainstem

PARTS OF THE BRAIN

• Largest part of brain• Divided into 2 hemispheres– A broad flat bundle of axons connects them, called

the corpus callosum– A layer of the dura mater separates the

hemispheres

CEREBRUM

• The ridges are called gyri• The grooves are called sulci– Deep sulci are called fissures

• Outer layer of cerebrum is gray matter called the cerebral cortex

• Inner layer of cerebrum is white matter

CEREBRUM

• Frontal lobe• Parietal lobe• Temporal lobe• Occipital lobe

LOBES OF CEREBRUM

• Higher intellectual processes for concentrating, planning, complex problem solving, and judging consequences of behavior

• Movements of voluntary skeletal muscles

FRONTAL LOBE

• Sensations of temperature, touch, pressure, and pain

• Understanding speech and using words to express thoughts and feelings

PARIETAL LOBE

• Hearing• Interpret sensory experiences and remember

visual scenes, music, and other complex sensory patterns

TEMPORAL LOBE

• Vision• Combine visual images with other sensory

experiences

OCCIPITAL LOBE

• Region of the brain that gives rise to posterior forebrain structures

• Associated with the Limbic System – controls emotion• Thalamus• Hypothalamus• Pituitary gland• Pineal gland• Amygdala• Hippocampus

DIENCEPHALON

• Relay sensory and motor information to cerebral cortex

• Regulates consciousness, sleep and alertness

THALAMUS

• Link between nervous system and endocrine system

• Releases hormones that eventually control body temperature, hunger, parenting behaviors, thirst, sleep, and circadian rhythms

HYPOTHALAMUS

• Endocrine gland stimulated by hypothalamus that secretes hormones that regulate homeostasis

PITUITARY GLAND

• Secretes the hormone melatonin, which regulates sleep/wake cycles and mood

PINEAL GLAND

• Role in memory, decision-making, and emotional reactions

AMYGDALA

• Involves consolidation of short-term memory into long term memory and spatial navigation

HIPPOCAMPUS

• A large mass of tissue inferior to cerebrum, posterior to brainstem

• Communicates with other brain structures by means of cerebellar peduncles.

• Integrates sensory info such as position of body parts, coordinates muscle activities, maintains posture

CEREBELLUM

• Connects brain to spinal cord• Midbrain• Pons• Medulla Oblongata• Reticular Formation

BRAINSTEM

• Joins spinal cord with higher regions of the brain

• Reflex centers that move eyes and head, maintains posture

MIDBRAIN

• A bulge on the underside of the brainstem• Relays impulses between medulla oblongata

and cerebrum; regulates breathing

PONS

• Enlarged continuation of spinal cord• Cardiac, vasomotor, and respiratory control

centers, nonvital reflex control centers

MEDULLA OBLONGATA

• Network of fibers throughout brain stem

• Regulates sleep/wake cycles, filters sensory impulses

RETICULAR FORMATION