Neuropsychology Module 2 & some of 3

Blood supply of brain and spinal cord, stroke, Neuron anatomy and physiology, Action and resting potential of neuron, neuron synapse, glai, visual pathway

where are the vessels in the brain

on the surface

where does blood enter the brain

through a hole in the skull

what is the hole in the skull where blood enters called/

foramina

what percentage of total body weight does the brain hold

2%

how much of the body blood supply does the brain receive

15-20%

what will happen if blood supply to the brain is stopped or altered

bain cells will die

What goes into brain by blood supply

oxygen, carbohydrates, amino acids, fats, hormones, vitamins

what goes out of the brain

carbon dioxide, ammonia, lactate, hormones

how many arteries supply the brain

2

which arteries supply the brain

internal carotid arteries and vertebral arteries

What do the right and left arteries form at the base of the brain?

the basilar artery

What do the basilar and blood supply of internal carotid arteries form?

the ring (circle of willis)

what is the circle of willis for?

the supply blood to brain even if other arteries or pathways are blocked

What is a brain attack?

a stroke

What causes a stroke?

when the blood supply of the brain is stopped or blocked

What can a stroke lead to?

paralysis or aphasia

What are the 2 major causes of strokes?

blockage or bleeding in the brain or neck

Where does blockage cause a stroke?

in the neck/brain

thrombosis

a blood clot in the brain or neck

embolism

blood clot from somewhere else that moved to brain/neck

stenosis

obstruction/narrowing of an artery in head/neck

hemorrhage stroke

bleeding of a blood vessel

symptoms of hemorrhage stroke

-sudden weakness/numbness in face/arm/leg on 1 side

-sudden dimness or loss of vision in one eye

-sudden difficulty speaking/understanding

-sudden severe headache

conditions linked to stroke

-high bp

-smoking

-heart disease

-diabetes

-transient ischemic attacks

Carotid

greek- kartosi= deep sleep

What is the eye in the visual pathway

the camera

what is the retina in the visual pathway

photographic film

what do the cornea and lens provide

focus

what adjust to light

iris

what is the retnia

layers of neurons

how are images displayed through retina?

focused images are inverted

structure of cornea

transparent, convex surface

what does the cornea hold

-no blood vessels

-aqueous humor

-tears

at resting membrane potential which ions cross the membrane easily?

K+

At resting potential which ions cannot cross the membrane easily?

Cl-, Na+

What ion cannot cross the resting potential membrane at all?

A-

What is the pump ratio for the cell mebrane

3 Na+ in/ 2K+ out

Which ions are more of on the inside of the membrane during resting potential K+ or Na+?

K+

When does action ptiental occur in a neuron?

When neuron send info down axon (away from cell body)

Depolarization current

explosion of electrical activity

what happens during a stimulus in a neuron?

resting potential decreases to 0mV (depolarization)

When is action potential fried?

When dp= -55mV

when is the threshold

-55mV

is the size of the action potential always the same, and why?

yes because of All or none principle

important ions in NS

K+, Na+, Cl-, Ca++, A-

when does action potential occur?

when diff ions cross membrane

What happens first when action potential occurs?

Na+ channel opens and rush into neuron ( makes more + and more depolarization)

What happens second when action potential occurs?

K+ channels open and rush out of neuron ( makes more - and less depolarization)

When does repolarization occur

when action potential goes back towards -70mV and beyond to stabilize

when does hyperpolarization occur?

when k+ stay open for to long and neuron goes beyond -70mV

What do Glia not do/ have

carry nerve impulses, resting potential, more than one processes, and chemical synapses

Can neurons work properly with out glia?

no

Astrocyte/ Astroglia

star shaped cells that provided nutrition and physical support, clean up, digest dead, and regulate extracellular space.

Microglia

digest dead neurons

Oligodendroglia

insulation (myelin) to neurons in CNS

Satellite cells

Support neurons in PNS

Schwann Cells

insulation( myelin) neurons in PNS

The similarities of neurons and other cells

-surrounded by cell membrane

-nuclei carries genes

-has cytoplasm and other organelles

-carry out basic cellular process

Diff of neurons from other cells

-dendrite ( info into cell)

-axon (infor out of cell)

how do you classify neurons?

by number of extensions

Bipolar Neurons

two processes extending from cell body

Pseudounipolar neurons

2 axons

1 axon goes to SPINAL cord;

1 axon goes to SKIN/MUSCLES

multipolar neurons

many processes (1 axon)

interneurons

send info between neurons

characteristics of axons

smooth, 1 per cell, myelin, further from cell body

characteristics of dendrites

rough, multipule, no myelin, near cell body

nucleolus in neuron

produce ribosomes= genetic info into proteins

nissi bodies in neuron

group ribosomes

er in neuron

transport materials through cytoplasm

Rough er: ribosomes protein synthesis

Golgi apparatus in neuron

package pesticides and proteins

microfilaments/ neurotubules in neuron

transport materials, structural support

oldest and longs cells in body

neurons

where can new neurons

hippocampus

synapses

where info flows between neurons

synaptic cleft

small gap between pre/post synaptic

presynaptic ending

neurotransmitter & organelles

postsynaptic

receptors

which way does and impulse travel on a axon to synaptic terminals?

down

what do electric impulses trigger?

migration vesicles

what does the vesicle membrane fuse with?

presynaptic membrane

what does the presynaptic membrane release?

neurotransmitter into synaptic cleft

Dale’s law (debunked)

1 neurotransmitter is made by a neuron

what do molecules that cross synaptic cleft bind with and what do they influence?

receptor sites and influence electrical response in postsynaptic

when does change in excitability happen

when neurotransmitter binds with receptor

when does continuation of “message” occur

with larger number of postsynaptic excitatory events

What arteries supply the spinal cord and brain?

the vertebral and internal carotid

where does the vertebral arteries come from

subclavian arteries

where does the internal carotid arteries come from?

common carotid arteries

What arteries supply the spinal cord

vertebral and 10 medullary

where do the medullary arteries come from

segmental branches of aorta

Medullary + vertebral arteries=

anterior and posterior spinal arteries

loss of posterior arteries in spinal cord =

loss of sensory function

loss of anterior arteries in spinal cord =

loss of motor deficits

at level of medulla vertebral arteries give off what?

branch of anterior spinal artery (10-12 count)

at level of pons right + left vertebral arteries =

midline basilar artery

basilar artery + internal cerebral artery =

posterior cerebral arteries

internal cerebral arteries + circle of willis =

posterior and anterior communicating arteries

anterior + middle cerebral arteries =

anterior circulation of forebrain

where do the anterior & middle cerebral arteries branch from?

circle of willis

branches from circle of willis support

cortex, basal ganglia, thalamus, internal capsule