neuroanatomy midterm fall 2023

what are the differences in the brain between species

• increased complexity connections as well as selective increases and decreases in certain brain sizes

• there are selective increases and decreases in across species

• Enhanced complexity of connections between structures

what is synesthesia?

• when a person has multiple sensory features in one area when normally there is only one sensory feature that is activated. One sensory modality can activate multiple modalities in this condition

• a condition where it affects 4% of population and there are over 60 different types

• it's something that they are born with, not learned or associated with

• NOT LEARNED BEHAVIOR

why does synesthesia happen?

• we form a lot of connections and then some start pruning when we do not utilize them or we maintain them, inhibiting one and activating the other.

• gene expression

• axonogenesis: for example, you get a number activation and then a color activation with it

• LSD: acid: cannot have synesthesia. Ex: Kanye west

the human brain…..

• contains 97% of the body's neural tissue

• spinal cord, peripheral nervous and the enteric nervous system make up about 3%

• average weight about 1.4kg (3lb)

• about 400g at birth

• adult range is 1100 -1700g

• reached about at 18 years of age ^

• its normal distribution, whether it weight less or more, it does not

• if it's bigger or smaller, that's where intellectual deficits may be seen.

• decline in weight starts at about at 50 years of age

• not consistent, it can happen in deep pits^

which of the following are not one of the 8 major regions of the brain?

• cortex (cerebrum)

• limbic system

• thalamus                    -  diencephalon 

• hypothalamus            - diencephalon

• pituitary gland

• cerebellum

• midbrain (mesencephalon)                                  - brain stem

• pons                                                                     - brain stem

• medulla oblongata

• pituitary gland

what is the sagittal section?

• separating left and right halves

what is the coronal (frontal) section?

• separating front and back halves

what is the axial (transverse, horizontal, cross logitunal) section?

• separates the top and bottom halves

what are the physical protectors of the brain?

• bones of the cranium

• cranial meninges

• cerebrospinal fluid: between arachnoid and pia

what is the biochemical isolator called in the protection of the brain?

• blood brain barrier

what is the blood brain barrier made up of? (cell type)

• endothelial

• also lines the blood vessels

what does the blood brain barrier cell type do?

• the endothelial cells form tight junctions to decrease the permeability, protects brain from anything, even tho some bacteria can flow through the blood

what cell type are the family member of endothelial cells?

• epithelial

how many layers do the cranial meninges have?

• 3

where is the dura mater (“tough mother”) attached to?

• attached to the inner surface of skull

what is the arachnoid mater (web-like matrix)?

• space between arachnoid and pia is filled with CSF

where is the pia mater (“tender mother”) attached to?

• attached to the brain

what are the functions of the cranial meninges?

• protect the brain from cranial trauma

• are continuous with spinal meninges

what are the dura mater composed of?

• inner fibrous layer (meningeal layer)

• outer fibrous layer (endosteal layer) which is fused to the periosteum

• venous sinuses form between the two layers (dural sinuses)

what is the arachnoid mater composed of?

• contacts epithelial layer of dura mater

• subarachnoid space: between arachnoid mater and pia mater

• covers brain

what are pia mater covered by……?

• many blood vessels and attached to brain surface by astrocytes

Veins will go to the dura sinus be filled with blood and CSF and deliver it to the __________ to go out to the body

jugular veins

where is the location and what is the function of the dural folds?

• inner layer of the dura mater

• extend into cranial cavity

• stabilizes and support the brain

• contain collecting

dural folds: what does the falx cerebri separates?

• projects into the longitudinal fissure between the cerebral hemispheres

• contains superior sagittal sinus and inferior sagittal sinus

dural folds: what does the tentorium cerebelli separate?

• separates cerebellum and cerebrum contains transverse sinus

dural folds: what does the falx cerebelli separate?

• divides cerebellar hemispheres below below the tentorium cerebelli

what is the order of CSF flow?

• lateral ventricles

• interventricular foramen

• third ventricle

• cerebral aqueduct

• fourth ventricle

how does CSF flow?

• posterior - anterior

• (anteriorly)

CSF surrounds…..

• all exposed surfaces of CNS

• interchanges with interstitial fluid of brain

what are the functions of CSF?

• cushions delicate neural structures

• supports brain

• transports nutrients, chemical messengers, and waste products

what is CSF made of?

choroid plexus

what is the choroid plexus cell type?

• ependymal

what does the choroid plexus do?

• secretes CSF into the ventricles

• remove waste products from CSF

• adjust composition of CSF

CSF produces…..

• 500ml a day

• 130 mLs within and around the brain and spinal cord at any given time

• about 20 mLs within the ventricles’ remainder in the subarachnoid space

• 3 times a day

• 10-30 mls normal

• L2 lumbar and stick a needle there and drain some CSF

• blockage can be in the cerebral aqueduct (obstruction) 

CSF circulates….

• choroid plexus

• through ventricles

• to central canal of spinal cord

• into subarachnoid space around the brain

• spinal cord

• cauda equina

what are the arachnoid villi?

• extensions of subarachnoid space

• excess of CSF and blood superior sagittal sinus: drains in internal jugular

• arteries; veins- venous sinuses (dural sinuses)

• extend through dura mater to superior sagittal sinus

what are the arachnoid villi?

• large clusters of villi

• absorb CSF into venous circulation

what are the arachnoid granulations?

• large clusters of villi

• absorb CSF into venous circulation

what is fontanelle?

• soft spot allows expansion of the brain and head, sutures will become sutures, movable joints

what are the functions of the cerebrum?

• conscious thought processes, intellectual functions

• memory storage and processing

• conscious and subconscious regulation of skeletal muscle contractions

what are the functions of the diencephalon?

• thalamus: relay and processing centers for sensory information

• hypothalamus: centers controlling emotions, autonomic functions and hormone production

what are the functions of the midbrain (mesencephalon)?

• processing of visual and auditory data

• generation of reflexive somatic motor responses

• maintenance of consciousness

what are the functions of the pons?

• relays sensory information to cerebellum and thalamus

• subconscious somatic and visceral motor centers

what are the functions of the medulla oblongata?

• relays sensory information to thalamus and to other portions of the brain stem

• autonomic centers for regulation of visceral function (cardiovascular, respiratory and digestive system activities) 

what are the functions of the cerebellum?

• coordinates complex somatic motor patterns

• adjusts output of other somatic motor centers in brain and spinal cord

what are supplied to the brain?

• supplies nutrients and oxygen to brain

• delivered by internal carotid arteries and vertebral arteries

• removed from dural sinuses by internal jugular veins

this structures supplies most of the telencephalon and diencephalon

• internal carotid

this structure supplies the brainstem and cerebellum as well as parts of the diencephalon, spinal cord and occipital and temporal lobes

• vertebral arteries

….. of the cerebrum receive blood from the internal carotid circulation

anterior regions

…….. of the cerebrum are supplied by the vertebral system

• ventral parts

what is the principal route of venous drainage is……

• through a system of cerebral veins that empty into the dural sinuses located between the 2 layers of dura mater and ultimately into the internal jugular veins

superficial veins lie on the surface of the cerebral hemispheres and empty into the ……

• sagittal sinus

deep veins drain internal structures and empty into the

• straight sinus

the ___________ and ___________ have their own complex collection of veins that drain into the sinuses

• cerebellum

• brainstem

ventral parts of the cerebrum are supplied by the

• vertebral system

what is a hemorrhagic stroke?

• blood vessels burst and downstream structures do not have oxygen

what artery is affected in the most common stroke?

• middle cerebral occlusion

what is the circle of willis?

• anterior cerebral arteries

• anterior cerebral communicating arteries

• posterior cerebral arteries

• posterior cerebral communicating arteries

the telencephalon drains

• cortex and subcortical areas

which vein drains for the face?

• external jugular

what is cerebrovascular disease?

• disorders that interfere with blood circulation to the brain

• stroke or cerebrovascular accident (CVA)

• neurons die and it shuts off a portion of the flow of blood to the brain

what makes up the blood brain barrier?

• endothelial cells

the blood brain barrier is formed by….?

• formed by network of tight junctions between endothelial cells of CNS

what does the blood brain barrier isolates?

• CNS neural tissue from general circulation

lipid soluble compounds (o2, co2), steroids and prostaglandins can diffuse into…..

• interstitial fluid of brain and spinal cord

_________ control blood brain barrier by releasing chemicals that control permeability of endothelium

• astrocytes

the blood CSF barrier surrounds…..

• capillaries of choroid plexus

• limits movement of compounds transferred

• allows chemical composition of blood and CSF to differ

four breaks in the BBB: portions of hypothalamus

• secrete hypothalamic hormones

four breaks in the BBB: posterior lobe of pituitary gland - not anterior

• secretes hormones (ADH and oxytocin)

four breaks in the BBB: pineal glands

• secretions

• melatonin: serotonin is necessary with the production

four breaks in the BBB: choroid plexus

• where special ependymal cells maintain blood-CSF barrier

where is slyme located?

• between arachnoid and pia

______ stabilize brain in cranial activity

• meninges

CSF protects against and provides…..

• sudden movement

• nutrients and removes wastes

the blood brain barrier and blood CSF barrier selectively isolate

• brain from chemicals in blood that might disrupt neural function

what does the brain stem process?

• information between spinal cord and cerebrum/cerebellum

what does the brain stem include?

• midbrain (mesencephalon

• pons

• medulla oblongata

what are the medullary and respiratory centers made up of?

• ventral and dorsal groups

what is the ventral group’s function?

• responsible for rhythmicity of breathing

what is the dorsal group’s function?

• inspiration of diaphragm

where will the impulses for respiration be sent to?

• intercostal muscle and diaphragm

the quicker the impulses the _________ the breathing gets

• faster

what is the pontine respiratory center function?

• interacts with medulla to smooth respiration

• provides tonic input to the medullary network

what are the higher centers of the brain?

• voluntary control

• pain

• emotion

• temperature

the higher centers of the brain will either……..

• stimulate or suppress the pontine respiratory center which will then suppress or stimulate the medullary respiratory center and respiration itself

what are the main influencers/stimulate of respiration?

• peripheral chemoreceptors

where are the chemoreceptors located?

• carotid and aortic arteries

the peripheral chemoreceptors detect……

• chemical changes in the blood.

• if they notice a change in decrease O2, decrease in PH, increase in H+, increase in CO2

what do the central chemoreceptors do?

• same thing as the peripheral chemoreceptors

where are the central chemoreceptors located?

• in the medulla

where else are there receptors in regards of respiration?

• joints and muscle

when is it important to breathe in and out faster to let the oxygen in and CO2 out?

• exercising

• it also improves all the acid buildup

what are irritant receptors?

• are protective of the lungs, this will send receptors to suppress and slow down breathing 

what are stretch receptors?

• (heuring breuer reflex)

• initiated by extreme over inflation of the lungs

the medulla sends impulses to the ________ nerve to slow down respiration

• vagus

what is the protective reflex in regards to respiration?

• are initiated by extreme over inflation of the lungs and therefore slow down respiratory rate

what are the functions of the medulla oblongata?

• regulates autonomic functions: heart rate, blood pressure, respiration and digestion

• coordinates complex autonomic reflexes

• controls visceral functions

• allows brain and spinal to communication

• relays information

what does the medulla oblongata connect?

• brain to spinal cord

what are some of the types of nuclei in the medulla?

• autonomic: control visceral activities

• sensory and motor: of cranial nerves

• relay stations: along sensory and motor pathways

autonomic nuclei: what is reticular formation made and function?

• gray matter with embedded nuclei

• regulates autonomic functions

• increases general arousal and can drive a person to an extreme emotional state