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The Neuron. Pathways to the Nervous System. The Neuron. before birth Approximately upon birth 90% of your cells are glia cells (in CNS) and Schwann cells (in PNS) (fun fact: prenatal neurons develop at the rate of 250,000/minute!!).

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The neuron

The Neuron

Pathways to the Nervous System


The neuron1
The Neuron

  • before birth

  • Approximately upon birth

  • 90% of your cells are glia cells (in CNS) and Schwann cells (in PNS)

  • (fun fact: prenatal neurons develop at the rate of 250,000/minute!!)


Nerve fibers are long dendrites and axons bundled together. They are called nerves in the PNS and tracts in the CNS

Nerves that lead to the brain are also known as:

Nerves going from the brain are:


Neuron

Parts: They are called nerves in the PNS and tracts in the CNS

dendrites

soma

nucleus,

nissl substance

axon

myelin sheath

nodes of Ranvier terminal feet

terminal buttons

Neuron


Chemicals contained in the terminal buttons are called neurotransmitters, which will leave:

The area between neurons is known as:


All or none law

The all-or-none law states that when a neuron is stimulated, it must stimulated to:

All-or-none law


Ways of measuring the brain
Ways of Measuring the Brain it must stimulated to:

Electroencephalograph-EEG-

Measures:

Used in sleep research, detects dreams and sleep disorders


Ways of measuring the brain1
Ways of Measuring the Brain it must stimulated to:

Lesioning

Intentional damage to brain cells:

Lesioning has taught us a lot about the functions of the brain


Ways to measure the brain

CT-Computerized Tomography it must stimulated to:

Horizontal slices:

Least expensive – widely used

Ways to Measure the Brain


Ways to measure the brain1

Positron Emission Tomography (PET) it must stimulated to:

Radioactive tracer

Color coded map

Ways to Measure the Brain


Ways to measure the brain2

Magnetic Resonance Imaging (MRI) it must stimulated to:

What it is:

Very expensive

Ways to Measure the Brain


Ways of measuring the brain2
Ways of Measuring the Brain it must stimulated to:

Electrical Stimulation of the Brain (ESB)

Sends a weak:

Stimulates areas of the brain to determine what effect the stimulation has

Discovered by Penfield, done:


Neurotransmitters it must stimulated to:


Acetylcholine ach
Acetylcholine-Ach it must stimulated to:

Involved in voluntary movements

Contributes to:

Lack of Ach –

Low levels of Ach – cells die


Acetylcholine
Acetylcholine it must stimulated to:

Hippocampus of the brain

Overabundance of Ach-

Curare-a poison that blocks the transmission of Ach, which will lead to intense spasms of the muscles, including heart –


Dopamine da

Controls voluntary muscles it must stimulated to:

A monoamine

Lack of –

Too much –

Dopamine-DA


Dopamine
Dopamine it must stimulated to:

Tardive Dyskenesia-a disease which can cause Parkinson’s-like tremors. This occurs when a person takes meds for:

Plays a major role in addiction as it is similar to adrenaline and controls:


Serotonin se

Highly implicated in it must stimulated to:

, hence your SSRI’s (antidepressants)

Low levels of SE seemed to be linked to:

Involved in wakefulness and:

A Monoamine

Serotonin-SE


Norepinephrine ne
Norepinephrine-NE it must stimulated to:

Low levels of NE have been associated with:

Cocaine and amphetamines may stimulate the activity of this neurotransmitter (may cause hallucinations)

A monoamine


Epinephrine

Synthesized by the: it must stimulated to:

Activates the sympathetic nervous system and puts the body:

Epinephrine


Endorphins

Resemble opiates it must stimulated to:

Pain blockers

Gate control theory:

Endorphins


Low levels: it must stimulated to:

Antianxiety drugs:

GABA


Central and peripheral nervous systems

Central Nervous System – it must stimulated to:

Consists of the:

Central and Peripheral Nervous Systems


Peripheral nervous system

Contains: it must stimulated to:

Somatic Nervous System:

Autonomic Nervous System:

Sympathetic NS

Peripheral Nervous System


Peripheral nervous system1

Parasympathetic it must stimulated to:

Rest and digest response

Brings the system back to:

Peripheral Nervous System


The brain

Did you know that the brain weighs only about 1 pound at birth?

By one year of age, the brain will double in size and be almost 90% of its adult size

The Brain


Lobes of the brain

FRONTAL LOBE birth?

Located in front of the central sulcus.

Concerned with:

Lobes of the Brain


Lobes of the brain1

Frontal Lobe- birth?

On the left side is Broca’s area –

Lobes of the Brain


Motor strip
Motor Strip birth?


Phineas gage

After Gage had an accident in which a metal pipe went through his brain, it was thought that he would not survive.

However, he did – with interesting consequences

Phineas Gage


Lobes of the brain2

PARIETAL LOBE through his brain, it was thought that he would not survive.

Located behind the central sulcus.

Concerned with:

Lobes of the brain


The Primary Somatosensory Cortex through his brain, it was thought that he would not survive.

Neurons in the primary somatosensory are activated when the skin is touched. However, the body is NOT represented in the cortex in proportion to the amount of skin.


A map of the human somatosensory cortex was drawn by Dr. Wilder Penfield in the 1950's.

By observing the location on the brain that caused patients to feel sensations on different parts of their bodies, Dr. Penfield was able to draw a map of the brain


Lobes of the brain3

TEMPORAL LOBE Wilder Penfield in the 1950's.

Located below the lateral fissure.

Concerned with:

Lobes of the Brain


Lobes of the brain4

Temporal Lobe – Wilder Penfield in the 1950's.

Behind the temporal lobe is the uncus –

Left side of temporal lobe is Wernicke’s area -

Lobes of the Brain


Lobes of the brain5

OCCIPITAL LOBE Wilder Penfield in the 1950's.

Located at the back of the brain, behind the parietal lobe and temporal lobe.

Concerned with:

Lobes of the Brain


The lobes of the brain

. Wilder Penfield in the 1950's.

The Lobes of the Brain


Medial view sensory motor areas
Medial View Sensory & Motor Wilder Penfield in the 1950's. Areas


The brain1

Brain Weight(gm) Wilder Penfield in the 1950's.

Species

6,000

Elephant

1,300-1,400

Adult Human

97

Rhesus Monkey

72

Dog

30

Cat

10

Rabbit

2.2

Owl

The Brain


How does the human brain compare
How does the human brain compare? Wilder Penfield in the 1950's.


Parts of the brain

Cerebral cortex functions: Wilder Penfield in the 1950's.

Thought

Voluntary movement

Language

Reasoning

Perception

Parts of the Brain


The hindbrain

Cerebellum Wilder Penfield in the 1950's.

Functions:

Looks like a mini-brain

The Hindbrain


Cerebellum
Cerebellum Wilder Penfield in the 1950's.

  • Two peach-size mounds of folded tissue at the base of the brain form the cerebellum.

  • Damage to this area leads to:

  • Some scientists have discovered:


The hindbrain1

Medulla Wilder Penfield in the 1950's.

Control of:

a.k.a. the medulla oblongata

The Hindbrain


The hindbrain2

Pons Wilder Penfield in the 1950's.

Located above the medulla

Connects midbrain with the:

Controls:

Contains sensory and motor tracts between the cortex and the medulla

Involved in:

The Hindbrain


The midbrain

The midbrain is very small in humans Wilder Penfield in the 1950's.

Coordinates simple movements with sensory information

The Midbrain


The midbrain1

Reticular formation (a.k.a. Reticular activating system) Wilder Penfield in the 1950's.

Attention and arousal-

If damaged, the person may:

Involved in pain perception

The Midbrain


The forebrain

Thalamus Wilder Penfield in the 1950's.

Functions as a relay station – sends sensory information to:

The only sensory information that does not travel through the thalamus is:

The Forebrain


The forebrain1

Hypothalamus Wilder Penfield in the 1950's.

Known for four F’s-

Although the pituitary gland is given credit for regulating the endocrine system, it is the hypothalamus that sends the message to:

The Forebrain


The forebrain2

Hypothalamus Wilder Penfield in the 1950's.

Regulates:

Controls your biological rhythms, so it is also involved with whether you are a morning person or an afternoon person

The Forebrain


The forebrain3

Limbic system: Wilder Penfield in the 1950's.

Regulation of emotions-

Also known for being involved with:

Hippocampus, amygdala, septum, part of the thalamus and hypothalamus

The Forebrain


The forebrain4

Hippocampus Wilder Penfield in the 1950's.

The Forebrain

  • Involved in memory and how we:

  • Removal of temporal lobe can result in:


The forebrain5

Hippocampus- Wilder Penfield in the 1950's.

Many memories are not stored there, however, the hippocampus sends information to different areas of the cerebral cortex for processing

The Forebrain


The forebrain6

Amygdala Wilder Penfield in the 1950's.

Plays a role in aggression and defensiveness

When damaged:

When stimulated:

The Forebrain


The forebrain7

Septum Wilder Penfield in the 1950's.

Important pleasure center of the brain – mild stimulation of this area may result in intense pleasurable feelings, including intense sexual arousal

Lesions to the septal area may result in:

Stimulation results in:

The Forebrain

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Corpus callosum

The brain has identical parts in each hemisphere Wilder Penfield in the 1950's.

The corpus callosum connects:

Often cut in patients with:

Corpus Callosum


Cerebrum

Largest part of the brain Wilder Penfield in the 1950's.

Divided into two hemispheres – each hemisphere has identical parts:

Separate by the-

Divided into four lobes

Cerebrum


Hemispheres of the brain
Hemispheres of the Brain Wilder Penfield in the 1950's.

  • Are you right-handed or left-handed?

  • About 90% of the population are right-handed - they prefer to use their right hand to write, eat and throw a ball ("right hand dominant.“)

  • Most of the other 10% of the population is left-handed or "left hand dominant."

  • There are few people who use each hand equally; they are "ambidextrous.”

Brain

Hemispheres


Marion diamond

Demonstrated that an enriched environment will increase cell weight and add to the number of dendrites on the neuron

An impoverished environment decreases cell weight:

Marion Diamond


Environmental impact on the brain

From the time a baby is born (and possibly before) they are beginning the formation of trillions of neuronal connections via the environment

Neurons will constantly grow, die, become stronger or weaker depending on the environment

Environmental impact on the brain..


Emotions and learning

Positive emotions, however, can enhance learning beginning the formation of trillions of neuronal connections via the environment

When students laugh or have positive feelings towards learning they are more likely to learn

Emotions and learning


The adolescent brain

“What were you thinking?” beginning the formation of trillions of neuronal connections via the environment

“Don’t you ever think before you act?”

“When are you going to make better decisions?”

“How many times do I have to say the same thing over and over again?”

Any of this sound familiar?

The Adolescent Brain


The adolescent brain1

The prefrontal cortex has not fully developed and the thinking, judging, planning portion of their brain is not functioning to its fullest capacity

The Adolescent Brain


The adolescent brain2

New research indicates that the adolescent brain has new cell growth and new neural connections

This new growth and the pruning of neurons not in use help the brain develop emotional maturity

The Adolescent Brain


Diseases of the brain

Alzheimer’s Disease cell growth and new neural connections

have gradual memory loss and difficulty with language and emotion

while the disease starts out slowly, it progresses to the point that the person needs help eating, bathing and using the bathroom

Diseases of the brain


Diseases of the brain1

Scans may help in the diagnosis cell growth and new neural connections

CAT scans tend to help visualize brain shrinkage and enlarged ventricles

Diseases of the brain


Diseases of the brain2

Research has demonstrated that the more neuronal connections one has, the more likely they are to lessen the effects of AD

Therefore, one should keep active physically and mentally

Diseases of the brain


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