Biological School

It is all about the body!!!!

The Nervous System

It starts with an individual nerve cell called a NEURON.

NeuroanatomySynapseSynapse

Neurotransmitters (chemicals held in terminal buttons that travel through synaptic gap)

How does a Neuron fire?• Threshold: level of stimulation

needed to trigger a neural impulse

• Action Potential: electrical charge that travels down the axon

• All-or-none response: neuron either fires or it doesn’t, nothing in beteween!

• Neurotransmitters: chemical messengers that cross synaptic gap b/w neurons• INFLUENCES EVERYTHING WE DO!!!

Move, feel…everything!• Reuptake: sending neuron

reabsorbs some of the neurotransmitter

Types of Neurons• Sensory Neurons

(Afferent): carry sensory information to brain & spinal cord (central nervous system)

• Motor Neurons (Efferent): carry information from brain & spinal cord to muscles & glands

• Interneurons: in bran & spinal cord that communicate b/w sensory & motor

TYPES OF NEUROTRANSMITTERS

Acetylcholine (ACH)• Deals with learning, memory,

& muscle movement • At every junction b/w motor

neurons & muscles– When released to our

muscles the muscle contracts

– When it is blocked muscles are paralyzed & cannot contract• Anesthesia?• Black widow spider?

• Is involved in autonomic nervous system

• Lack of has been linked to Alzheimer’s disease

Dopamine• Involved in movement &

posture, alertness, & leveling out mood

• Cocaine (and other drugs) blocks dopamine reuptake=high

• Lack of dopamine has been linked to Parkinson’s disease

• Too much has been linked to schizophrenia (overstimulated brain)

Serotonin

• Involved in mood, appetite, arousal

• Low levels have been linked to clinical depression, suicide, loss of appetite (anorexia)

GABA (gamma amino-butyric acid)

• In Central Nervous System

• Induces relaxation & sleep

• Balances the brain• Too little = insomnia,

anxiety, epilepsy

Glutamate• Involved in memory

& learning• Low levels =

interferes with memory & learning, sluggish, difficulty concentrating

• High levels = must be “reuptook?” or it can destroy neurons

Endorphins

• Natural pain killers• Feeling of euphoria,

pleasurable emotions• Opiates (morphine,

codeine…) bind to receptors– Many of our most addictive

drugs deal with endorphins

• Produced during exercise – “gym rats”

Drugs can be…..

• Agonists- make neuron fire• Antagonists- stop neural

firing• Reuptake Inhibitors- block

reuptake

The Nervous System

Central Nervous System

•The Brain and spinal cord•CNS

Peripheral Nervous System• Peripheral: sensory &

motor neurons that connect the Central NS to the rest of the body– It’s how the brain & spinal

cord communicate w/ sensory receptors, muscles & glands

– Travel through nerves (bundled axon cables that connects cns to eveything)

• Is divided into two categories….somatic and autonomic

Somatic Nervous System

• Controls voluntary muscle movement

• Uses motor neurons

• Let’s make a list!

Autonomic Nervous System• Controls the

automatic functions of the body– Glands, organs,

heartbeat, digestion, etc…

• Think AUTOMATIC• Divided into two

categories…the sympathetic and the parasympathetic

Sympathetic Nervous System

• When you are stressed:– Automatically

accelerates heart rate, breathing, raises blood sugar, sweat to cool you down…

• Fight or Flight Response!– You body feels

“sympathy” for you b/c it thinks you are about to die so it gets you ready to fight or run

Parasympathetic Nervous System

• Automatically slows the body down after a stressful event

• Heart rate and breathing slow down, lowers blood sugar, etc…

• Think PARACHUTE

Reflexes• Automatic response

to stimuli• Normally, sensory

neurons take info up through spine to the brain– Some reactions occur

when sensory neurons reach just the spinal cord (interneurons)

• Survival adaptation?

Brain Structures

• Some scientists divide the brain up into three parts.

• Hindbrain• Midbrain• Forebrain

• Let’s talk first about the brainstem (hindbrain)

Medulla Oblongata

• “Central Office”=keeps your whole body working

• Located where spinal cord enters the skull

• Controls heart rate, breathing & blood pressure

Pons

• Located above medulla

• Communicates between cerebellum & other parts of brain

• Involved in sleep & arousal (awake)

• Some think involved in dreaming

SPINAL CORD

• (the nerves) interneurons that carry signals

• protected by vertebrae & spinal fluid (cushions the nerves)

Thalamus• Located in Forebrain• “Brain’s Sensory

Switchboard”– 2 egg shaped structures

• receives information from all the senses (except smell) & routes it to the brain regions that deal with vision, hearing, taste & touch

• it’s the main traffic hub en route to other destinations

Reticular Formation(reticular activating system)

• Located between your ears

• Finger-shaped network of neurons located between spinal cord & thalamus

• Sensory info travels from spinal cord to thalamus & some passes thru RF which filters info & relays it to other areas of the brain

• controls arousal (alert)– Stimulate that cat! Or put in

in a coma

Cerebellum• means “little

brain”• located in the

back of our head• Coordinates

muscle movements, balance, & emotions

Limbic System• EMOTIONAL CONTROL CENTER of

the brain• Linked to emotions (fear, anger…),

memory & motivation (food, sex…)• The 4 “F”s– Feeding– Fighting– Fear– F (sex )

• Made up of:*Hypothalamus *Hippocampus *Amygdala *Cingulate Gyrus

Hypothalamus• “the brain’s thermostat” • perform specific bodily

maintenance duties (eating, drinking, body temperature, sex drive…), takes orders from the other parts of the brain– “pleasure center”

• Orchestrates the sympathetic nervous & endocrine systems– interplay b/w endocrine & nervous

systems, both influence each other

– EX: thinking about sex can trigger your body to secrete hormones

•

Hippocampus and Amygdala

• Hippocampus is involved in memory processing (creating new memories)– Think lost on campus as a

freshmen on first day– Shaped like a seahorse– Damage to this area will

prevent you from forming new memories

• Amygdala is vital for our basic emotions– Expressions of Fear &

Aggression/Frustration

Cingulate Gyrus

• Latin for “belt”• emotional responses

to pain• regulates aggressive

behavior• Helps predict

negative consequences

The Brain• Made up of neurons

and glial cells• Glial cells are the

“housekeepers” that support & provide nutrition to neural cells

My husband is my glial cell. He takes care of me (and cleans the house)!!!

Cerebral Cortex• The wrinkled outer layer of

our brain• Laid out it would be about

the size of a large pizza (yum!)

• YOUR BODY’S ULTIMATE CONTROL & INFO PROCESSING CENTER

• Thinking, perceiving, speaking

• This part of our brain separates us from all other animals

Areas of the Cerebral Cortex• Divided into eight

lobes, four in each hemisphere (frontal, parietal, occipital and temporal)

• Any area not dealing with our senses or muscle movements are called association areas– Deal with higher

mental functions like learning, remembering, thinking & speaking

Frontal Lobe• Deals with higher level

thought & reasoning– Making plans, forming

judgments, performing movements

• Motor Cortex: controls voluntary movements

• Prefrontal Cortex: problem solving & emotion

• Broca’s Area: left hemisphere in frontal lobe, controls ability to speak (muscles)– Broca’s Aphasia: damage to

Broca’s area will impair speaking

Parietal Lobes

• Located at the top of our head

• Receives sensory info about temperature, pressure, texture, & pain

• Somato-sensory cortex: registers and processes touch and movement sensations

Temporal Lobes

• Located above the ears• Process sound sensed by

ears• Wernicke’s area:

processes the words we hear spoken– Wernicke’s Aphasia: impairs

your ability to understand words

• Angular Gyrus: responsible for understanding written language

Occipital Lobes

• Located in the back of our head

• Handles visual input from eyes

• Right half of each retina goes to left occipital lobe and vice versa (seriously!!!)

Corpus Callosum & Basil Ganglia

• Corpus Callosum: a large band of neural fibers that connect the 2 hemispheres of the brain (we’ll talk about what happens when you cut this this soon)

• Basil Ganglia: group of neurons that learns, remembers, & coordinates voluntary movement (Williams in Zumba!!!!)

Hemispheres

• Divided into a left and right hemisphere.

• Contralateral controlled- left controls right side of body and vice versa.

• Brain Lateralization.• Lefties are better at

spatial and creative tasks.

• Righties are better at logic.

Split-Brain Patients

• Corpus Collosum attaches the two hemispheres of cerebral cortex.

• When removed you have a split-brain patient.

Brain Plasticity

• The ability for our brains to form new connections after the neurons are damaged.

• The younger you are, the more plastic your brain is.

Ways to study the Brain!!!• Accidents: Phineas

Gage.

LesionsCutting into the brain and looking for change.

Brain tumors also lesion brain tissue.

Less Invasive ways to study the Brain

• Electroencephalogram (EEG)

• Computerized Axial Tomography (CAT)

• Magnetic Resonance Imaging (MRI)

• Positron Emission Tomography (PET)

• Functional MRI

CHECK OUT LINK ON WEBSITE FOR MORE INFO!

Endocrine System• System of glands

that secrete hormones.

• Controlled by the hypothalamus.

• Pituitary=“master gland”

• Ovaries and Testes.• Adrenal Gland