NERVOUSSYSTEM:

The Brain

100 billion neurons

Weighs 3 pounds Gray and white

matter Cerebrum = 85%

of total mass of brain

Brain Factoids…

4 main areas of brain

1. Brain stem2. Cerebellum3. Diencephalon4. Cerebrum

– 2 halves (hemispheres– 4 lobes

Highly-wrinked part = cerebral cortex

Covered by Meninges

CEREBRAL CORTEX

Sensory perception Willed movements Consciousness Memory Subcortical=

subconscious

Lobes of the Brain

1. Frontal Lobe Associated with

– Reasoning– Planning– Parts of speech– Movement– Emotions– Problem solving– Personality

You are who you are because of this lobe. This area determines personality and emotions. It's also involved in controlling judgment, impulses, sexual behavior, language and movement.

2. Temporal Lobe Associated with

– Perception and recognition of auditory stimuli

– Memory– Speech

This region controls your hearing and the ability to recognize words. It can also affect memory. Damage to the left side of this lobe can cause problems remembering what people said. Damage to the right side might stop you from recalling music or pictures.

Damage to…

Broca’s Area>> expressive aphasia – Know what you want to say, but can’t get the words out

properly– Yes... ah... Monday... er... Dad and Peter H... (his own

name), and Dad.... er... hospital... and ah... Wednesday... Wednesday, nine o'clock... and oh... Thursday... ten o'clock, ah doctors... two... an' doctors... and er... teeth... yah.

Wernicke’s Area:>> receptive aphasia– No problem getting the words out, but the sentences

don’t make sense– “I called my mother on the television and did not

understand the door. It was too breakfast, but they came from far to near. My mother is not too old for me to be young.”

3. Parietal Lobe

Associated with – Movement– Orientation– Recognition – Perception of stimuli

This region of the brain helps people understand what they see and feel. It also controls how they understand and process information about the environment around them, such as distance and position of objects.

4. Occipital Lobe

Associated with – visual processing

Call this the visual center. This area determines if you understand what you're looking at. Damage to the occipital lobe could cause hallucinations, make objects appear larger or smaller then they are or make the colors look abnormal.

Check out brain lobe function Brain video: The work of neurons

CORPUS CALLOSUM

Broad band of white matter

Contains axons that connect the right and left cerebral hemispheres

Brain Stem & Associated Structures

Cerebellum Brainstem

– Midbrain– Pons– Medulla Oblongata

Spinal Cord

CEREBELLUM Regulates muscle coordination Maintains equilibrium Stores movement patterns Posture

Histology of the cerebellum

Cerebellum & Brainstem

BRAINSTEM

Relay Station– Connects brain to the spinal cord

Runs from the thalamusto the spinal cord

Composed of 3 parts– Midbrain– Pons– Medulla Oblongata

Life center- controls – breathing– heart rate– blood pressure

A. Midbrain Superior portion of the

brainstem Contains relays for visual

and auditory impulses

1. Midbrain 2. Cerebellum 3. Pons 4. Medulla oblongata 5. Inferior colliculus 6. Superior medullary velum 7. Fourth ventricle

B. Pons

Middle portion of the brainstem

Is a conduction pathway from body to thalamus/cerebrum/ cerebellum

Regulates respiration

C. Medulla Oblongata Inferior portion of the brainstem

that controls– Cardiac function– Respiratory function– Vasomotor centers

SPINAL CORD Carries messages to and from the

brain and the rest of the body Mediates reflexes

Describe a reflex arc.

Two-neuron reflex arc:

Impulse from sensory neurondendrite cell body in dorsal root ganglion,

near SC (Ganglion: group of hundreds of nerve cell

bodies located in the PNS.)axon synapse

To motor neuron– dendrite cell body (in gray matter of SC)

– axon which runs through the ventral root of a spinal nerve

To effector

Limbic System & Associated Structures

Limbic System– Hippocampus– Amygdala– Thalamus– Hypothalamus

Pituitary Gland Pineal Gland

thalamuspinealgland

LIMBIC SYSTEM: emotional brain

Hippocampus Amygdala Thalamus Hypothalamus

A. Hippocampus

Plays a role in long term memory

B. Amygdala

Plays a key role in processing emotion

Linked to – fear response – pleasure

Perceive, integrate, respond

C. Thalamus

Sensory relay station from various areas of the body to the cerebral cortex

Involved with – emotion – alerting mechanisms– arousal mechanisms

D. Hypothalamus

Maintains Homeostasis Releases hormones to the pituitary

gland Regulates

– body temperature– water balance– sleep-wake cycle– sexual arousal– aggression/pleasure– eating/drinking

HypothalamusPituitary Target Glands/Organs

Pituitary Gland

Releases sex and growth hormones

Stimulates lactation Stimulates uterine

contractions

Regulates urine output

Pineal Gland

Involved in the body’s sleep/wake cycle