PSYC 301 - Structural Anatomy

major divisions of the nervous system

peripheral nervous system (PNS) and central nervous system (CNS)

how is the PNS further divided into

somatic nervous system (SNS) and autonomic nervous system (ANS)

SNS

component that interacts with the external environment

differences between afferent nerves and efferent nerves 

afferent nerves carries towards the CNS but efferent nerves carries away from the CNS 

what does the afferent servers in SNS carry

it carries sensory signals in from the world around us towards the CNS using sensory neurons 

what is an example of afferent nerves in the SNS

detecting lights, sounds, smells etc

what does efferent nerves in SNS carry

it carries motor signals from the CNS out to the skeletal muscles using motor neurons  

what is an example of efferent nerves in the SNS

information from the brain to cause muscle to contract or flex

ANS

nerves that participate in the regulation of the internal environment of the body and its internal processes

what does the afferent nerves in ANS carry 

it carries sensory signals from the internal organs to the CNS

what is an example of afferent nerves in the ANS

when stomach is full, information gets sent to the brain to stop eating

what does the efferent nerves in the ANS carry

it carries motor signals from the CNS to the internal organs 

what is an example of efferent nerves in the ANS

heart rate should increase so it causes the heart to beat faster

what are the two types of nerves in efferent nerves 

sympathetic nerves and parasympathetic nerves 

sympathetic nerves

mobilises energy in threatening situations causing physiological arousal that acts via glands or organs

example for sympathetic nerves

inhibiting saliva and increase in heart rate in threatening situations

parasympathetic nerves

act to conserve energy or “rest and digest”

example of parasympathetic nerves 

stimulating digestion 

what are we always in a state of

in a state of balancing sympathetic and parasympathetic nerves

what are clusters of cell bodies in the PNS called

ganglion

what are bundles of axons called in the PNS 

they are called a nerve and axons are often called nerve fibres

what is the CNS composed of 

brain and spinal cord 

what are clusters of cell bodies called in the CNS

nucleus

what are bundles of axons called in the CNS

tract 

label spinal cord 

what is the inner h shaped of the spinal cord made up of

gray matter 

what is the gray matter of the spinal cord made up of (3)

cell bodies, unmyelinated axons and capillary blood vessels

what is the surrounding area of the spinal cord made up of 

white matter 

why is the surrounding spinal cord area white

due to myelinated axons wrapped in fats that carries messages very quickly

why do we need the both grey and white matter (2)

• to carry information long distance very quickly that is supported by white matter

• to process information supported by grey matter

how does grey matter and white matter differ in the thoracic curve (upper back)

more white matter than grey matter due to more information passing through at this part of the spine 

how does grey matter and white matter differ in the sacral curve (lower back)

more grey matter than white matter as it receives and processes more information than passes information

neuroanatomical directional terms in rats (6)

• dorsal: towards the top

• ventral: towards the bottom

• rostral: towards the nose

• caudal: towards the tail

• anterior: towards the front

• posterior: towards the back

neuroanatomical directional terms in humans head (4)

• dorsal: top of head

• ventral: bottom of head

• anterior: towards face

• posterior: towards back

neuroanatomical directional terms in humans spinal cord (2)

• ventral (anterior): front of the body

• dorsal (posterior): back of the body

left and right neuroanatomical terms (3)

• lateral: out to the side 

• medial: middle of the person 

• always view L and R from the POV of the patient 

what are the 3 different sectional planes

• horizontal plane

• coronal plane

• sagittal plane

horizontal plane

oval- like, symmetrical

coronal plane 

like a latin crown, can see top of person’s head and maybe their neck 

sagittal plane

“arrow”, not symmetrical

very early in development, 18-21 days old human embryo, what are the 3 divisions of the brain that can be seen

• hindbrain

• midbrain

• forebrain

before birth, these 3 swellings become what five structures 

• telencephalon 

• diencephalon 

• mesencephalon 

• metecephalon 

• myelencephalon 

what is part of the forebrain

telencephalon and diencephalon

what is part of the midbrain

mesencephalon

hindbrain

metecephalon and myelencephalon

myelencephalon (2)

• aka medulla 

• composed largely of tracts carrying signals between the rest of the brain and the body 

what are the two part composed of the metecephalon 

pons and cerebellum 

pons (3)

• houses many fibre tracts

• part of reticular formation

• has lots of white matter

what is reticular formation (2)

• network of nuclei that play roles in arousal, attention, cardiac and respiratory reflexes

• in myelcenphalon, metecephalon and mesencephalon

cerebellum (3)

• “little brain” 

• massively connected to cortex, multiple cerebro- cerebellar systems 

• involved in movement and timing - matching motor signal and sensory feedback 

is the cerebellum part of the brainstem

no

what are the 2 components of mesencephalon

tectum and tegmentum

tectum 

• “roof”

• contains nuclei that receive and relay visual and auditory information

what is the nuclei that relay visual information

superior colliculi

what is the nuclei that relay auditory information

inferior colliculi

tegmentum (2)

• “floor”

• contains nuclei related to motor function and processing pain

what is the nuclei that is related to motor function 

subutancia nigra and red nucleus 

what is the nuclei related to processing pain called

periaqueductual grey

are the abilities in the mesencephalon common across all vertebrate

yes it is not uniquely human and it is conserved evolutionarily

injuries to which regions of the brain are less survivable 

injuries to mid and hindbrain due to them being involved in heart rate, breathing, being alert etc 

what are the 3 disorder of mid and hindbrain learnt in class

• Dejerine syndrome

• Chiari malformation

• pontine tegmental cap dysplasia

dejerine syndrome (4)

• bilateral medial medullary

• respiratory failure

• paralysis of all four limbs

• includes tongue dysfunction

chiari malformation (2)

• compression and distortion of cerebellum due to skull shape causing it to make its way down the spinal cord

• surgery can be done to relive pressure

what are the symptoms of chiari malformation (5)

• headaches

• neck pain

• coordination issues

• swallowing issues

• can be asymptomatic

pontine tegmental cap dysplasia (2)

• rare genetic disorder of pons and cerebellum formation due to developmental error in axon growth and guidance

• affects hearing, gaze, swallowing and facial movements

what is the diencephalon composed of

thalamus and hypothalamus

thalamus (2)

• 2 lobed structure, bilateral

• made up of many different types of nuclei - some process and relay sensory information between the receptors and cortex 

nuclei in the thalamus

may be specific to one sense or non specific and involved in multimodal integration simultaneously 

thalamo- cortical loops and consciousness (3)

• relationship between the thalamus and the cortex is important to have a subjective experience of consciousness 

• general anaesthetics tend to act upon the non specific nuclei of the thalamus 

• abnormal synchronisation in the thalamo cortical network can cause absence seizures, moments of unconsciousness 

hypothalamus (2)

• plays an important role in autonomic type functions such as feeding, sex, sleeping, temperature, emotion and movement 

• also bilateral and symmetrical 

what does the hypothalamus act upon 

acts upon the body’s endocrine system via the pituitary gland - sends messages to pituitary glands to release different 

hypothalamic and pituitary tumours symptoms (5)

• headache, seizures 

• feedings and weight changes 

• energy and mood changes 

• cognitive changes 

• hormonal changes 

telencephalon

largest division of the brain

what are the 3 structures that make up the telencephalon

• basal ganglia

• limbic system

• cerebral cortex

basal ganglia (2)

• collection of nuclei highly connected to the cortex, thalamus and midbrain

• involved in movement and learning, esp recognising patterns 

what 2 structures are composed of the limbic system 

hippocampus and amygdala 

hippocampus

plays a role in spatial memory and episodic memory

amygdala 

plays a role in emotion

cortex (3)

• also known as cerebral cortex 

• outer surface of the brain 

• it is highly folded and convoluted in order to get max surface area into a finite volume

do different animals have different folding of the cortex

yes

what is a gyrus 

the top of the folds 

what is a sulcus

the bottom valley of the folds

if a sulci is deep enough to indent the ventricles what is it called

fissures

90% of the human cerebral cortex is…

isocortex or neocortex, means that there is 6 layers

10% of the human cerebral cortex is…

allocortex, less than 6 layers

what the different layers specialised to do

either to receive information from other brain structures, output information or process information

why is it important that during development the layers are formed properly

as if the cells do not migrate normally, folding is interrupted which can lead to Lishencephaly, a smooth brain

Lishencephaly (4)

• happens between 12-40 per million birth 

• symptoms can include seizures, muscle spasm, developmental delays etc 

• many children with Lishencephaly will die before the age of 10 due to seizure ore respratory function 

• can be genetic or non genetic 

the cerebral hemisphere are connect by a few tracts called 

the cerebral commissures 

what is the largest track

the corpus callosum

what are the 4 parts of the cortical lobes

• frontal lobe

• parietal lobe

• occipital lobe

• temporal lobe

• all bilateral

what are the landmarks used to delineate between the lobes called 

sulcus and fissures 

what is the sulcus distinguishing the frontal and parietal lobe

central sulcus

what is the sulcus distinguishing the frontal and temporal lobe

lateral sulcus

what is the sulcus distinguishing the left and right side

longitudinal sulcus

what is part of the brain stem 

mesencephalon, metencephalon (pons) and myelencephalon 

what are fluid filled spaces in the brain called and what do they contain

they are called ventricles and contain cerebrospinal fluid (CSF)

what are the 3 main roles CSF play

• buoyancy

• protection

• chemical stability

buoyancy (2)

• dense brain is suspended in fluid, reduces its effective weight

• does not interfere with blood supply or put pressure on lower structures 

protection 

reduces injury upon head impact