Neuroscience Quiz 2 Rhodes College

Neurons

are electrically excitable cells in the nervous system

Parts of the Neuron

Dendrites, cell body, axon, axon terminals

Parts of the cell

nucleus, mitochondria, Golgi apparatus, cytoplasm, ribosomes, and endoplasmic reticulum

Sensory Neurons

receive information from external environment (Ex: eyes)

Motor neurons

send information directly to muscles

interneurons

all other neurons

Glial cells

support cells of the nervous system

Astrocytes

form blood brain barrier and modulate neural activity

Oligodendrocytes

wrap cell membranes around axons to form myelin sheath

Microglia

devour and remove damaged cells

Electrochemical signals

What neurons use to receive, evaluate, and transmit information

Order of Neurons

Presynaptic -> Synapse -> Postsynaptic Neuron

Ions

Small electrically charged particles

Channels

Pores in the neural membrane that ions can flow through

Chemical gradients

difference in solute concentration across the neural membrane

Electrical gradients

difference in charge across the neural membrane

What is the resting membrane potential?

The difference in electrical potential across the neural membrane at rest.

Which ions are more concentrated outside the neuron at rest?

Sodium (Na+)

Which ions are more concentrated inside the neuron at rest?

Potassium (K+)

What maintains the resting membrane potential?

Ion channels and the Na+/K+ pump.

What is the threshold?

-55 mV

Action Potential

membrane potential increases enough to surpass threshold

depolarizes

Voltage-gated Na+ channels open → Na+ flows into neuron

repolarizes

Voltage-gated K+ channels open → K+ flows out of the neuron

hyperpolarizes

Voltage-gated K+ channels are open longer than Na+ channels → K+ keeps flowing out of the neuron

refractory period

Voltage-gated K+ channels close → resting membrane potential is restored, and Voltage-gated Na+ channels are inactivated

nodes of Ranvier

where regeneration takes place creating saltatory conduction

Signal flow

Presynaptic terminal -> Postsynaptic terminal

Step 1 of Chemical signaling

Voltage gated Ca2+ channels open and Ca2+ flows into the axon termina

Step 2 of Chemical signaling

Ca2+ influx causes vesicles to fuse with presynaptic membrane

Step 3 of Chemical Signaling

NTs are released from vesicles

Step 4 of Chemical Signaling

NTs bind to receptors on postsynaptic neuron

Excitatory synapse

↑ chances of action potential and Ions+ flow in or ions- flow out

Inhibitory synapse

↓ chances of action potential and Ions- flow in or ions+ flow out

Glutamate

Primary excitatory NT in the brain

GABA (gamma-aminobutyric acid)

Primary inhibitory NT in the brain

Agonists

enhance the action of NTs (L-Dopa)

Antagonists

diminish the action of NTs (Propranolol)

The nervous system

is a network of neurons working together to convey information throughout the body

Central Nervous System

consists of the brain and spinal cord

Peripheral Nervous System

connects the CNS to the body's muscles and organs

Somatic Nervous System

consists of sensory nerves and motor nerves

Autonomic Nervous System

controls organs

Parasympathetic nervous system

promotes activities at rest

Sympathetic nervous system

prepares the body to act in a challenging or threatening situation (flight or fight)

parasympathetic and sympathetic nervous systems

coordinate to control many bodily functions, and often complement each other

Human Brain

3 pounds, 86 billion neurons, Specialized sections, and areas work together in networks

Moving to the top of the brain

dorsal/superior

Moving to the bottom of the brain

ventral/inferior

Moving forward to the front of the brain

rostral/anterior

Moving to the back of the brain

caudal/posterior

Cut of brain down the middle

sagittal

cut of brain from side to side (looks like a crown)

coronal

cut of brain that splits top and bottom

axial

Outermost layer of brain

dura mater

Layer after the dura mater

arachnoid mater

layer after the arachnoid mater

pia mater

CNS is covered by three protective membranes called:

meninges

Ventricles

are hollow spaces filled with cerebrospinal fluid

How many lateral ventricles are there

two

Where is the third ventricle

under the two lateral ventricles

where is the fourth ventricle

under the fourth ventricle

Are the more complex functions of the brain at the top or bottom

Top

Are the less complex functions of the brain at the top or bottom

bottom

Hindbrain

controls vital bodily functions (respiration)

Midbrain

controls orientation toward pleasurable stimuli and away from threatening stimuli

Forebrain

controls complex sensory, cognitive, and motor functions

Where is the Cerebral cortex

In the forebrain

Gyri

are ridges on the cerebral cortex

Sulci

are grooves between gyri

Frontal lobe

movement, planning, decision making

Parietal Lobe

touch and spatial awareness

Temporal lobe

Audition and Language

Occipital Lobe

vision

Where are the Subcortical regions

located in the forebrain

What is Grey matter made of

Neuron cell bodies

What is White matter made of

Axons and glia

Pons

relays information between the cerebellum and the rest of the CNS

Medulla

coordinates respiration, heart rate, and blood pressure

Cerebellum

controls fine motor skills

Corpus callosum

connects the two hemispheres

What is the Thalamus

relays sensory information to the cerebral cortex

What is the Hypothalamus

regulates certain bodily states (e.g., hunger, thirst)

What is the Basal ganglia

is a set of structures that controls voluntary movement

What does the Hippocampus support

memory functions

What does the Amygdala support

emotion functions

Cranial nerve 1

Olfactory (smell)

Cranial nerve 2

Optic - vision

How many cranial nerves and what do they do

relay information between the brain and the head and neck

What are brain lesions

are damage to neural tissue and can be caused by (Stroke, Tumor, Neurodegeneration, Traumatic brain injury)

Example of Brain Lesion given in class

Metal spike going through the frontal lobe of Phineas Gage

What is Electroencephalography (EEG) used for

Each electrode records cumulative electrical activity from thousands of neurons (measures brain function)

What can EEG's measure

Attention • Seizure • Anesthesia • Coma • Sleep stage

Other electrical recording methods

Fine-tipped microelectrodes can be placed in or near a neuron to measure changes in electrical potential (help locate source of seizures)

What is magnetic resonance imaging (MRI) used for

measure brain structure

Signal strength of MRI depends on what (density of what type of atoms)

H atoms

Grey matter is higher or lower in water content

Higher making it darker

White matter is higher or lower in water content

Lower making it lighter

Signal strength of MRI depends on what (amount of what type of atom)

Oxygen

Do active neurons use more oxygen

Yes