FUNDAMENTALS OF NEUROSCIENCE: Anatomy

neuroscience

scientific study of the nervous system

objectives of the field

• understand the function and structure of healthy nervous systems across organisms

• treat diseases and injuries of the nervous system

• apply our knowledge of the nervous system to improve the quality of human life

approaches to neuroscience

• basic (preclinical)

• applied (clinical)

basic (preclinical approach)

discovering fundamental principles and theories

applied (clinical approach)

solving problems and discovering drugs, clinical techniques, and medical advices

nervous system organization

brains-systems-maps-circuits-neurons-synapses-molecules

specialization in neuroscience

• development- growth from embryo

• synaptic/cellular-biology of brain cells and communication between them

• sensorimotor- perceiving and moving throughout the environment

• integrative- regulation of the body and hormones

• cognitive-representing and processing information

• motivation/emotion- responding to external events and internal drives

trepanation

Used in ancient France, a practice of drilling holes in the skull to relieve pressure, drain abscesses, or release evil spirits

dualism

the idea that the brain and mind are on separate planes of existence

monism

idea that the mind as we experience it is a product of brain function

radial symmetry body plans

organisms that tend to have a decentralized nervous system

bilateral symmetry body plans

organisms that tend to have a centralized nervous system with sensory organs on the head and the head facing the directions of locomotion

central nervous system

consists of the brain and spinal cord; centralized along the major axis of the body

peripheral nervous system

includes all nerve endings that extend beyond the CNS

Blastocyst stage

• after initial rounds of cell division, cells begin to organize into a hollow sphere called a blastocyst that implants into the uterine lining

• within the blastocyst the inner cell mass forms into the epiblast and hypoblast

• epiblast will go on to form most embryonic tissue

  • ectoderm, mesoderm, and endoderm

gastrulation and germ layers stage

a hollow tube that will form the gut is created and the epiblast around that space separates into three germ layers with different tissue fates

• ectoderm

• mesoderm

• endoderm

ectoderm

outer layer that will form nervous system and skin

mesoderm

middle layer that will form muscle, bone, and connective tissue

endoderm

inner layer that will form most internal organs

neurulation/ neural tube formation

sheet like layer of the ectoderm will roll and close into a tube

1. formation of the neural plate within the neural ectoderm

2. invagination of the neural plate to form neural grooves, as the borders of the neural plate converge to form neural crests

3. closure of the neural tube and complete seperation from the epidermal ectoderm

notochord

a temporary mesoderm structure that grows between the developing gut and neural tube; releases chemical signals that direct the organization of the nervous system from the neural tube

the tripartite embryonic brain

the neural tube then segments into a 3 part structure

1. prosencephalon- forebrain

2. mesencephalon- midbrain

3. rhombencephalon- hindbrain

prosencephalon-forebrain

• telencephalon- cerebral cortex, hippocampus, amygdala, part of basal ganglia

• diencephalon- thalamus, hypothalamus, epithalamus

rhombencephalon (hindbrain)

• metencephalon- cerebellum, pons

• myelencephalon- medulla oblongata

neurons

specialized cells that communicate via electrical chemical signaling

soma

cell body that contains nucleus and organelles

neurites

specialized extensions of the cytoplasm (axon or dendrites)

input signals

collected and integrated in processes called dendrites

output signals

generated in the axon and passed to the next neuron through axon terminal

morphology

shape and arrangement of neuron

anaxonic

no axon, just dendrites

bipolar

two processes; 1 axon and 1 dendrite

unipolar/pseudounipolar

one main process that may branch

multipolar

single axon multiple dendrites

glial cells in CNS

non neural electrically active cells

• astrocytes

• ependymal cells

• microglia

• oligodendrocytes

astrocytes

regulate blood flow and extracellular chemical environment

ependymal cells

form a barrier lining the walls of the CNS

microglia

apart of the brains immune system

oligodendrocytes

wrap around the neuronal axon and provide insulation so that signal travel faster and further

glia in the PNS

• Schwann cells

schwann cells

major glia in the pns that insulate axons beyond the spinal cord; can help regenerate injured nerves in pns

cerebral cortex

• telencephalon structure

• specialized regions that process and integrate information

• separated into frontal, parietal, occipital, and temporal lobes

• source of consciousness

• crumpled to maximize space

  • gyrus-grooves

  • sulcus-ridges

hippocampus

• telencephalon structure

• beneath the cortex in the temporal lobe

• spatial learning and navigation

• helps form new memories of experiences through sensory information

amygdala

• adjacent to the hippocampus in the temporal lobe

• helps form memories concerning emotional (rewards/ aversive) things or events

• behavioral and physiological responses to emotional experiences

thalamus

• diencephalon structure

• major relay station for sensory information besides smell

• all information will go through the thalamus before going to the telencephalon

• can shut down external sensation and motor output during sleep

hypothalamus and pituitary gland

• diencephalon structure

• work together to maintain hormones and homeostasis

• growth and development

• hunger

• temperature regulation

• stress response

mesencephalon (midbrain) strcutures

• helps process sensory information which allows for quick responses

• also helps with reward and motivational drive

pons

• rhombencephalon (hindbrain) structures

• sleep, arousal, eye movements, facial expressions, breathing

medulla oblongata

• rhombencephalon (hindbrain) structures

• breathing, heart rate, blood pressure, vomiting

cerebellum

• rhombencephalon (hindbrain) structures

• motor coordination and learning

• cognitive and emotional roles as well

limbic system

• work together to process emotional expeirnces, form memroies of those expereinces, and use them them to structure behavioral responses

• hippocampus, amygdala, cingulate gyrus of cortex, thalamus

basal ganglia

work to learn movements and link behavioral goals to those movements

afferent

incoming information into the dorsal spinal cord

efferent

motor information leaves from the ventral spinal cord

cerebrospinal fluid

the inner space of the nerual tube and space between the brain and skill is filled with cerebrospinal fluid which cushions, provides nutrients, get rid of cellular waste

choroid plexus ependymal cells

produce cerebrospinal fluid

interconnected ventricles

inner space of the CNS
-3rd thalamus

-4th brainstem

-central canal spinal cord

-paired lateral ventricles cortex

meninges

3 layered membrane structure originating from neural crest and mesoderm that line and protect outer boundary of the CNS

• duramatter

• arachnoid

• piamater

duramatter

thick outer layer of the meninges against the bone

arachnoid

web like membrane bewteen the dura and pia mater contians csf and blood vessels

pia mater

thin membrane adhering tightly to the neural tissue

peripheral nervous system

• nervous tissue that is neither the brain nor spinal cord

• recieves sensory information and relays it to the cns

• recieves motor effector commands from the cns and relays them to target organs

autonomic nervous system

• heart muscle, smooth muscle, glands

somatic nervous system

• voluntary skeletal msucles

• 12 cranial nerves

• 31 spinal nerve pairs

• sensory=dorsal

• motor=ventral

sympathetic ans

flight or fight

parasympathetic

rest digest