I. Nerve Organization

A. Nerve Net – Limited synapses between neurons.

B. Ganglia – Local cluster of nerves.

C. Cephalization – Head formation and bilateral semetry allow for complex brain function.

Fig. 35.3, p. 589

ganglion(brainlike structure)

one oftwo nervecords

segmentalganglion

rudimentary brain

nerve chord

brain

nerve chord

optic lobeconnectedwith visualstimuli

brain

one oftwo nervecords

FLATWORM EARTHWORM

CRAYFISH GRASSHOPPER

II. Division of Nervous System

A. Cell Types

1. Gray Matter – Neurons without myelin

sheath

2. White Matter – Neurons with fatty

myelin sheath.

3. Neuroglia – Cells of nervous system

other than neurons (Schwann cells).

II. Nervous System (con’t)

B. Brain and Body

1. Central Nervous System: Brain and

Spinal Cord.

Surrounded by membrane called

meninges (blood/brain barrier).

2. Peripheral Nervous System: Nerve

bundles extending beyond CNS.

Fig. 35.5, p. 591

BRAIN

CRANIALNERVES

SPINALCORD

ulnarnerve

lumbarnerves(five pairs)

sacral nerves(five pairs)

coccygeal nerves(one pair)

cervical nerves(eight pairs)

thoracic nerves(twelve pairs)

sciaticnerve

II. Nervous System (con’t)

C. Divisions of Peripheral Nervous System

1. Somatic Nerves – Skeletal muscles,

voluntary actions, skin, limbs, etc.

2. Autonomic Nerves - Nonvoluntary

actions; smooth and cardiac muscles;

glands.

II. Nervous System (con’t)

C. 2. Divisions of Autonomic Nerves

a. Parasympathetic: Basic biological

functions; resting state.

b. Sympathetic: Increased awareness and

immediate energy; ‘nervousness.’

Nervous System

Central Nervous SystemPeripheral Nervous

System

Somatic Nervous System

AutonamicBrain Spinal Cord

Sympatheic Parasympathetic

Fig. 35.6, p. 591

CENTRALNERVOUSSYSTEM

brain

spinal cord

sensorynerves

axons ofmotor nerves

somaticsubdivision

(motor functions)These nerves carrysignals to and fromskeletal muscles,tendons, and skin.

autonomicsubdivision

(visceral functions)These nerves carrysignals to and frominternal organs (gut,heart, glands, etc.).

parasympatheticnerves

sympatheticnerves

PERIPHERAL NERVOUS SYSTEM

Fig. 35.4a, p. 590

FOREBRAIN. Receives, integratessensory information from nose,eyes, and ears; in land-dwellingvertebrates, contains the highestintegrating centers

MIDBRAIN. Coordinates reflexresponses to sight, sounds

HINDBRAIN. Reflex control ofrespiration, blood circulation,other basic tasks; in complexvertebrates, coordination ofsensory input, motor dexterity,and possibly mental dexterity

(start of spinal cord)

III. Very Basic Divisions of Brain

A. Hindbrain: Brain stem in humans. 1. Medulla oblongata: respiration, circulation. 2. Cerebellum: Coordinates inputs; necessary for coordination and motor skills. 3. Pons: Bridge between hindbrain and midbrain.

Fig. 35.12, p. 596

hypothalamus thalamus pineal gland location

corpuscallosum

part of anopticnerve

midbrain

cerebellum

pons

medulla oblongata

III. Basic Divisions of Brain (con’t)

B. Midbrain: Greatly reduced in humans.

Coordinates sight and sound in many

vertebrates.

III. Basic Divisions of Brain (con’t)

C. Forebrain: Most recent evolutionary component of brain.

1. Divided into two hemispheres 2. Cerebrum in mammals. 3. Thalamus: Relay or bridge to Cerebrum 4. Hypothalamus: Links brain with endocrine system; controls homeostatis.

IV. Details of Cerebrum

A. Cerebral Cortex: Outer gray covering. Infolding increases surface area.

B. Frontal Lobe: Associated with ‘higher thinking’

C. Parietal Lobe: Motor and sensory nerves.

D. Temporal Lobe: Speech and Auditory nerves.

E. Occipital: Sight.

Fig. 35.10, p. 595

Fig. 35.12, p. 596

hypothalamus thalamus pineal gland location

corpuscallosum

part of anopticnerve

midbrain

cerebellum

pons

medulla oblongata

Fig. 35.13, p. 597

Motor cortex activitywhen speaking

Prefrontal cortex activitywhen generating words

Visual cortex activitywhen observing words

Frontal lobe(planning ofmovements,aspects ofmemory,inhibition ofunsuitablebehaviors)

primarymotorcortex

primarysomatosensory

cortex

parietallobe

(visceralsensations)

temporal lobe (hearing,advanced visual processing)

occipital lobe(vision)

IV. Details of Cerebrum (con’t)

F. Hemispheres:

1. Right: Visual/Spatial, music, ‘creative’

2. Left: Speech, math, ‘analytical’

3. Connected with Corpus Callosum

G. Limbic System:

Role in memory and emotion.

PET Machine