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?

• Resting Potential: slightly negative charge.

• Reach the threshold when enough neurotransmitters reach dendrites.

• Go into Action Potential.• All-or-none response.• Transfer of ions across

axon’s membrane causes electrical charge.

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• Black widow spider?

• Is involved in autonomic nervous system

• Lack of has been linked to Alzheimer’s disease & ADD

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

Types of Neurons

• Efferent (Motor) Neurons

• Interneurons• Afferent (Sensory)

Neurons

The Nervous System

Central Nervous System

•The Brain and spinal cord•CNS

Peripheral Nervous System

• All nerves that are not encased in bone.

• Everything but the brain and spinal cord.

• Is divided into two categories….somatic and autonomic.

Somatic Nervous System

• Controls voluntary muscle movement.

• Uses motor (efferent) neurons.

Autonomic Nervous System

• Controls the automatic functions of the body.

• Divided into two categories…the sympathetic and the parasympathetic

Sympathetic Nervous System

• Fight or Flight Response.

• Automatically accelerates heart rate, breathing, dilates pupils, slows down digestion.

Parasympathetic Nervous System

• Automatically slows the body down after a stressful event.

• Heart rate and breathing slow down, pupils constrict and digestion speeds up.

Reflexes

• Normally, sensory (afferent) neurons take info up through spine to the brain.

• Some reactions occur when sensory neurons reach just the spinal cord.

• Survival adaptation.

The Brain

• Made up of neurons and glial cells.

• Glial cells support neural cells.

My fiance is my glial cell. He takes care of me!!!

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

Brain Structures

• Some scientists divide the brain up into three parts.

• Hindbrain• Midbrain• Forebrain

• Let’s talk first about the brainstem

Medulla Oblongata

• “Central Office”=keeps your whole body working

• Located where spinal cord enters the skull

• Controls heart rate, breathing & blood pressure

Pons

• Connects hindbrain, midbrain & forebrain together

• Involved in facial expressions

SPINAL CORD

• (the nerves) interneurons that carry signals

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

Cerebellum• means “little

brain”• located in the

back of our head• Coordinates

muscle movements & emotions

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 that relays info to other areas of the brain

• controls arousal & ability to focus attention

Limbic System• EMOTIONAL CONTROL CENTER

of the brain• Linked to emotions (fear,

anger…) & basic motives (food, sex…)

• The 4 “F”s– Feeding– Fighting– Fear– F (sex)

• Made up of Hypothalamus, Amygdala, Hippocampus & 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

• 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”• Helps regulate

emotion & pain• Monitors and guides

behavior• Helps predict

negative consequences

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.

Endocrine System

• System of glands that secrete hormones.

• Controlled by the hypothalamus.

• Ovaries and Testes.• Adrenal Gland