Studying the Brain

Part of brain destroyed

-done in the lab w/ lab animals

-those who have brain damage already are studied to see what they can & cannot do

Studying the Brain

Stimulate the Brain (talk to brain)

-with chemicals/electricity and observe reactions

1. chemicals that are similar to what is already in brain

2. electrical probes

3. primarily work w/ lab animals

4.done with humans when needed

Studying the brain

Look at brain activity (listen to the brain)

-look at electrical activity under various conditions

1. EEG-brain produces wavelike electrical activity, research & diagnostic tool

2. CT Scan-3D picture of the brain; detects abnormal brain tissue & injuries

3. PET-look at diff levels of brain in a flat image, what part of brain is being used in diff. situations

4. MRI-3D image; uses magnetic fields/radio wave pulses to instruct images; look at changes in blood

Nervous system

Central

1.brain

2. spinal chord

-Nerve=collection of neurons outside central system

-Tract=bundle of neurons inside central system;

A-sending: sensory info

D-sending: motor info, muscle movement

-interneurons=type of neurons

Nervous System

Peripheral

1. Somatic: soma = body; way we control body&sense things from environment; muscles we consciously control;movement of skeletal muscles, sensation

2. Autonomic: housekeeping activities, automatic functions (heart rate, digestion pressure...)

-arousing mechanism, prepares us for handling an emergency

-releases certain chemcials (adrenalin)

-increases blood flow to skeletal muscles

help recover from handling an emergency

decrease blood pressure & heart rate, less stressed

3 types of Neurons

Glia Cells

1. Sensory (Input): located in peripheral nervous system; controlled by a simple touch

2. Motor (Output): attached to skeletal muscles, located in peripheral

3. Interneurons (In between): mechanism for spinal reflex

*Glia Cells--

-made of fatty tissue

-fill in space between neurons(support/protect)

-remove waste

-help some neurons communicate more effectively

Structure of Neuron

Dendrites

Structure of Neuron

2. Soma

contains all parts of cell that normal cell would contain

life-keeping function of cell

Structure of Neuron

3. Axon

length of cell

electrical current is generated & transmitted

axon-ilic

Structure of Neuron

4. Myelin Sheath

found on some axons

fattly like substance made of glia cells, wraps around axon

electrical insulator

1 mm-20 mm, length about 3 ft.

*Multiple Sclerosis(MS): occurs when the myelin sheath starts to deteriorate

Structure of Neuron

5. Terminals

end

Terminal Buttons: contain vesicles/sacs of chemcials which open and release chemicals out

in the axon

collection of neurons primarily myelinated

in axon

non myelinated nerve tissue

-70 mv

polarized

not capable of firing

all or none

depolarized

capable of firing

-Neurotransmitters in terminal buttons

-The Synapse: small gap between terminal button of sending neuron & dendrite of recieving neuron

-binding sites on dendrties

-reuptake: recycles unused neurochemicals

Neurotransmitters

Dopamine

usually inhibitory

Not enough=Parkisons Disease

Too Much= Schizophrenia

Neurotransmitters

Acetylcholine

usually excitatory

used with motor movements in central/peripheral nervous system

Underproduction: Alzheimer's Disease

Neurotransmitters

Serotonin

"feel good", feeling of content

affects sleep-dreaming, general arousal

imbalances=depression, OCD, schizophrenia

Neurotransmitters

GABA

Neurotransmitters

Endorphins

modulates effectiveness of other neurotransmitters

morphine like chemicals serving as body's painkiller

The Brain

Hindbrain

most primitave portion of the brain: 4 structures

1. Cerebellum: located in the back of the brain, means "little brain", primary function helps to coordinate muscle movements, involved with some extent language, reasoning, and memory tasks

2. Brainstem:

-Medulla & Pons -- both help heart regulation, breathing, and blood pressure, as well as certain reflezes(gag, sneezing, coughing)

serve as a neuron network of pathways

-Reticular Formation: network of specialized neurons in the brainstem (arousal, sleep, attention...)

The Brain

Midbrain

(also on brainstem)

-Tectum=superior & inferior colliculus: involved with coordination of reactions to sensory events from our environment

-Tegmentum: involved with movement and arousal as well as sensory orientation, pleasure seeking, dopamine production

-Substantia nigra: group of neurons that releases dopamine, smoothes out muscle movement

The Brain

Forebrain

1. Subcortical(inner part)

-Thalamus: on stem, primary relay station, gathers info from senses and send it out to other areas of brain

-Hypothalamus: right in front of thalamus, deals with eating, drinking and sexual motivation, regulates body temp.

-Limbic System: formation of new memory

*Hippocampus-protruding structures, if damaged can no longer form new memory

*Amygdala- almond shaped, linked to emotional and motivational senses(anger/fear)

2. Cerebral Cortex(outer part)

LOBES

-Temporal: located on sides by ears, processes auditory info

*Wernicke's Area: left temporal lobe only, language comprehension

-Opcipital: located in back of brain, processes visual info

-Parietal: located top back

*Somatosensory Cortex: located in the front part of the Parietal, processes sense of touch, temp and pain

-Frontal: planning and decision making, memory strategies, personality, regulation of self control

*Motor Cortex: located next to somatosensory cortex, processes fine movements(hands,toes,facial...)

*Broca's Area: Located in left part of frontal lobe, speech production

Hemispheres-two connected halves of brain

Corpus Callosum-connects the two hemispheres

*Contra-lateral organization: left side of brain controls right side of body & vice versa

*Lateralization of Function: certain functions are produced by the left side of brain while other functions are produced by the right

Endrocrine System

Hormones

travel throughout blood stream sending different sensations to target cells, released though different glands and organs

travel slower for longer distances

have a lasting effect

The Endocrine system

Neurotransmitters

tavel very quickly throughout body

short distances

have a fleeting affect

The Endocrine System

Adrenal & Pituitary Glands

recieves signals from hypothalamus and tells other glands to release hormones

Adrenal:  releases adrenalin and energy