Central Nervous System

At what rate does the human brains use oxygen and glucose?

at x10 the rate of the rest of the body

True or False: the brain is less than 2.5% of body weight but 20% of the body’s energy consumption

true

General purposes of the brain

basic survival (unconscious operations) and conscious decisions and responses

What are meninges?

membranes that cover and protect the CNS

what are the 3 layers of the meninges?

Dura Mater, Arachnoid mater, pia Mater

What is the Dura mater?

attached to inner surface of skull, protects brain from displacement

what does the arachnoid mater do?

transports cerebrospinal fluid from brain ventricles back into blood vessels

What is the pia mater?

attached tightly to brain

where is cerebrospinal fluid produced?

within ventricles

what are ventricles?

spaces within brain

what does cerebrospinal fluid do?

protects and cushions the brain and spine

Parts of brain?

frontal, parietal, occipital, temporal lobe, brainstem, and cerebellum

3 main regions of the brain

brainstem, cerebellum, cerebrum

what does the brainstem control?

basic life functions

what does the brainstem contain

pons and medulla oblongata

what does pons control?

motor control and sensory analysis

what does medulla oblongata do?

breathing and heart rate

what does the cerebellum do?

controls regulation and coordination of movement/balance/power

what does the cerebrum do?

controls higher level functioning

what is the cerebrum covered with?

gyri and sulci

what are gyri

Ridges or bumps on the brain's surface

what are sulci

Grooves or indentations between the ridges

what does the cerebrum contain?

frontal, parietal, temporal, and occipital lobes

what is the brain divided into?

2 hemispheres

what connects the hemispheres

corpus callosum

what does the corpus callosum allow for?

allows for communication between sides

what does the frontal lobe do?

controls executive functioning skills and long term memories

what executive functioning skills does the frontal lobe control?

controls planning, problem solving, motivation, judgement, decision making, impulse control, social behavior, personality, memory, learning, reward, attention

what does the temporal lobe control?

auditory, speech, and memory

what does the temporal lobe contain?

Amygdala and hippocampus

what is the amygdala?

controls flight or flight instinct, memory, emotion, and fear

what is the hippocampus

controls learning, short term memory, and regulated emotions

what does the parietal lobe control?

movement, recognition, perception of stimuli (touch, pressure, temp, and pain)

what does the occipital lone control?

vision

what is the thalamus?

place where sensory information travels through before going to cerebral cortex

what is the hypothalamus?

maintains homeostasis and controls automatic responses and pituitary gland

what does the nervous system do?

gathers info (sensory input), interprets info and determines response (integration), causes response (motor output)

What are the subdivisions of the Nervous system?

central and peripheral nervous system

what makes up central nervous system?

brain and spinal cord

what makes up peripheral nervous system?

all neurons lateral to CNS

What are neurons?

nerve cells that communicate

Do neurons ever divide?

NO they never go through mitosis, they stay in G0

characteristics of neurons

long life span, amitotic, high metabolic rate

what does amitotic mean?

cannot reproduce

what do neurons constantly require?

energy and oxygen

can neurons go through anaerobic respiration?

no

What are neuroglia?

nerve cells that do not communicate

What do neuroglia make up?

neural networks

what do neuroglia do?

they are the glue that hold the nervous system together and nourish neurons to promote growth and health

roles of neuroglia

scaffolding for cells to climb, remove debris from dead cells (after injury), role in neuron maturation (add myelin)

what are the types of neuroglia

astrocytes and schwann cells

what are astrocytes

star cells; are the clean up crew of the nervous system

what do astrocytes do?

they nourish neurons and maintain appropriate chemical environment (mop up toxins)

what are Schwann cells?

type of neuroglia that form the myelin sheath around axons; is living component 

What is the myelin sheath?

a coat for the axon of a neuron

what is the myelin sheath made of?

lipids and proteins

What does the myelin sheath surround?

the axon of a neuron

what does the myelin sheath allow for?

allows for quick nerve impulse transmission and provides insulation to axon

What happens to the myelin sheath after 9-18 months after birth?

myelin forms in motor neurons of leg muscles; allows for walking

When do the neuroglia clean up?

when we sleep

what is needed for astrocytes to clean up neural networks

sleep

what occurs if astrocytes stop working?

alzheimer's

what is multiple sclerosis?

a autoimmune disorder where WBC fight cells of myelin sheath, causing scarring

what does multiple sclerosis result in?

results in delayed or blocked signals that control muscle coordination, strength, sensation and vision

what causes the scars to form?

white blood cells attacking

where does multiple sclerosis first occur?

in motor neurons

what is the prefrontal cortex?

the region at the very front of the brain's frontal lobe that is crucial for executive functions, such as planning, decision-making, personality, and self-control

What are the functions of the PFC

executive functioning, reflective (considers feelings and response), long term memory, emotional management

What neural networks mature last?

the ones in the PFC

Where does info go to if it doesn’t go to the PFC?

it goes to the remaining 80% of the brain (which is reactive)

How is information transferred?

Begins in peripheral nervous system → amygdala → PFC (forms long term memory and learning occurs)

What is the amygdala sensitive to?

stress

what does stress increase?

dopamine

what does increased dopamine cause

inhibits nerve impulses → stops transfer of info to the PFC

How can you regulate dopamine levels?

by regulating stress

What are dopamine levels like?

goldilocks, too little is bad, too much is bad

what does stress shrink?

neural networks (neurons communicating together)

What does low stress cause?

low stress → low metabolic activity → info goes to PFC → can learn

what does high stress cause?

high stress → hyper metabolic activity → info goes to reactive part of the brain → cannot learn

what are the effects of stress in the Harvard study?

stress floods the brain with cortisol

what is cortisol?

a hormone

what does excess cortisol do?

it impairs memory

what did the harvard study do?

tested group a people trained in meditation shown to reduce stress hormones levels

what did harvard discover after 8 weeks?

researchers took MRI’s of both groups (placebo and meditation) and it showed that the density of the gray matter in the hippocampus increased significantly in the meditation group

what does the hypothalamus control

controls homeostasis

what does increased gray matter show?

communicating neurons

What are pets scans used for?

used to observe brain activity

how do pet scans work?

radioactive glucose injected → travels to brain → working part of brain lights up on scale

what is metalizing

making connection between “old” information and new circumstances

What are neural networks?

arrangements of neurons in a circuit

what do neurons pass?

electrical impulses on to the next neuron

How do we strengthen neural networks?

through use

What happens to neural networks when we sleep?

proteins strengthen things

What does maturation in neural networks result in?

neuroplasticity

What does electricity from impulses lead to?

more dendrites → more neural networks, more myelin formation (more maturation), more intentional synapse connections (better communication

What does greater brain activity result in?

greater neuroplasticity

is neuroplasticity moldible?

yes

What is neuroplasticity?

the brains ability to form new neural networks throughout life

what does neuroplasticity allow for one to do?

learn and adjust to new situations

what does neuroplasticity result from?

continual proces of pruning and myelation