Biopsych Exam 1

Golgi staining and the nerve net

Ramon y Cajal

one guy, figured out synapses

Years later after synapses was discovered… what else was figured out?

Phrenology

if you damage one part of the brain you’ll see

Discovery of neurons was made possible from what

the nerve net (Golgi) and synapses (Ramon y Cajal)

Who discovered the nerve net?

Golgi

What did Ramon y Cajal discover?

That there is space between the neurons and that they don’t connect.

He looked at development neurons and saw that there was a synapse.

Took long for them to figure out how they send signals.

Neurons similarly to other cells…

have cell bodies (mitochondria, golgi apparatus, ribosomes, etc.)

How are neurons different from cells?

In how their structure allows them to communicate

How do the parts of a neuron allow them to communicate? What happens at each place?

Through dendrites, axons, and axon terminals

dendrites:

axons:

axon terminals: package up the neuron signals

Do neurons in the central nervous system 

Meninges (pia mater, dura mater, arachnoid mater)

serve to hold the brain in place

pia mater- soft

dura mater- hard

arachnoid mater- 

Ventricles and CSF

Fluids are good cushions, nice and shock absorbent

the CSF also takes bad stuff out and flushes the brain out

Skull and backbone

Blood brain barrier

How do we learn new things?

Because of changes in dendritic spines and dendtritic arborization

through experiences there are changes in dendritic spines and dendrites branching out more or in different ways (arborization)

—> as a result, transmission of signals and communication changes and we learn

What are changes in dendritic spines/what is dendritic arborization?

dendritic spines: like buds on a tree//there can be new buds that grow

dendritic arborization: dendrites branching out more and more making it more complex (mostly seen in development)

What are the four glial cells?

Astrocytes, microglia, oligodendrocytes, and schwann cells

Astrocytes

Regulate blood flow supplying oxygen and nutrients to neurons

Microglia

“little garbage men”

remove debris

Oligodendrocytes

form myelin in Central Nervous System

Schwann cells

form myelin in Peripheral Nervous system

What does myelin do?

It wraps around the axon to protect the signal to allow it to travel through the whole neuron

Neural circuit

When two or more neurons communicate 

What are the three main types of neurons

Sensory, interneurons, and motor neurons

Sensory neurons

Interneurons

Motor neurons

What does the presynaptic neuron do?

What does the postsynaptic neuron do?

Receives signal at dendrites

Peripheral Nervous System (PNS)

Nerves outside of brain and spinal cord

Central Nervous System (CNS)

What are the types of nerves?

What two systems are part of the Peripheral Nervous System?

Autonomic nervous system:

Somatic nervous system: voluntary motor movements and sensory processing

What are the three systems in the autonomic nervous system?

Sympathetic: 

Parasympathetic:

Enteric nervous system: used to be classified as parasympathetic, about digestion, what is it, know that it is new

Spinal cord nerves

each nerve has two distinct branches/roots

Two roots in spinal cord

Dorsal root

Ventral root

Hindbrain

Functions that keep us alive, not specifically human

Cerebellum

Midbrain

Tectum: superior colliculi and inferior (auditory) colliculli - low level vision and hearing

Tegmentum: neurotransmitter tracts, arousal, consciousness, motor control

Forebrain

Cerebral cortex

Limbic system

Thalamus

Hypothalamus

Cerebral cortex

In the forebrain

Does a lot of things and is an intentional system

When you’re thinking about something and purposefully doing something

vision, memory, decision making, emotions (learning and appraisal), language, attention, behavior control and regulation

Limbic system

emotions, memory, learning, emotional regulation

Thalamus

selecting, choosing, and relaying information to cerebral cortex

has a role in attention by selecting the information that proceeds to the cerebral cortex (where it’s processing it further)

(thalamus says oh there’s a lot of red, relays to that to the cerebral cortex, and then the cerebral cortex focuses on one red chair… sees shape.. distinguishes it as a chair)

Hypothalamus

regulating basic drives— sex, hunger, thirst, temperature

Problem with early brain imaging techniques

allowed people to see into the brain (CAT scan) and its functions (PET scan) but used radiation

CAT give you an image

PET give you activity

Electroencephalography (EEG)

measuring electricity in brain

allows us to record electrical activity in real time, poor localization of function

recording from the skull of the neurons firing (where the electricity is coming from)

the localization is bad— you cant specifically tell where the electrical signals that are seen are coming from

EEG = when and NOT where

(MRIs you see exactly from where but not when,

EEGs you see when but not where)

MRI

newer technology

showing structure of brain

fMRI

newer technology

not radioactive

showing function of brain activity

WHERE not when

Diffusion tract imaging (DTI)

newer technology

Neurophysiology

the signaling of neurons

Ions

bits that make us us (?)

two types: cations and anions

Anions

negative

Cations

Positive

Na+, Cl-, and K+

NaCl outside and potassium inside,

sodium wants to come in and potassium wants to go out (?)

Cell membrane

semi-permeable, only lets certain things in

Intracellular fluid

mainly K+ in the intracellular fluid

but is supposed to be more negative (?)

Extracellular fluid

NaCl — salty fluid outside of the neuron

Resting potential

Action potential

Polarization

Depolarization

close to zero, becoming less opposite of each other (?)

Selective permeability

Diffusion

Electrostatic pressure

When a threshold is met…

gates open up and Na+ rushes into the membrane causing DEPOLARIZATION

How does information travel through neuron?

would jump faster if there was no myelin (?)

Myelinated axons

saltatory conduction

saltary conduction

nodes of ranvier

IPSPs

EPSPs

Spatial summation

Temporal summation

Loewi’s dream experiment

takes one heart, stimulates Vegas nerve

then in another cup that is connected with fluids that can connect between the two

he’s recording how fast each one beats

first heart slows down as the nerve is stimulated

just the fluid trickling into the other leads the other heart beat to slow down as well

says it is evidence that there is some chemical in the fluid that is causing the reduction in the heart rate

first evidence that chemicals existed

What is the sequence of synaptic transmission?

What are ligands and what are their two types

Ligands:

Two types: endogenous and exogenous

Endogenous ligands

neurotransmitters and hormones

Exogenous ligands and their subtypes

Drugs and toxins

— agonists (substitute for neurotransmitter/hormone)

increase the effect of a neurotransmitter

— antagonists (block without effect or reduce availability)

• antagonists (block without effect or reduce availability)

• decrease the effect of a neurotransmitter

take place of the receptors

Ionotropic receptor

Metabotropic receptor

How does the removal of a neurotransmitter from a synapse work?

Degradation

Removal by glia

Diffusion

Reuptake

What does an electroencephalogram (EEG) measure?

measuring electricity from the surface of the skull because neurons transmit electric signals

What are the four main categories of neurotransmitters? don’t need to know anything other than which things are in each category

Amino acids- GABA, glutamate

Amines- acetylcholine, dopamine, serotonin, epinephrine/norepinephrine

Peptides- short chain amino acids (neuropeptides)

Gases- soluble gases, nitric oxide, and carbon monoxide