The CNS

brain stem

a central cavity surrounded by grey matter, with a layer of white matter externally that contains scattered regions of grey matter (nuclei)

cerebrum

a central cavity surrounded by grey matter, with a later of white matter externally that contains scattered regions of grey matter (nuclei) and is encircled by an outermost layer of grey matter

spinal cord

a central cavity surrounded by grey matter, with a later of white matter externally that that lacks scattered regions of grey matter (nuclei)

what makes up grey matter

short, nonmyelinated axons, neuron cell bodies, and dendrites

what makes up white matter

myelinated axons with some nonmyelinated axons, primarily in fibre tracts

what is contained within the brain ventricles

cerebrospinal fluid (CSF)

lateral ventricles

located in the cerebrum

third ventricle

located in the diencephalon

fourth ventricle

located in the brain stem and the cerebellum

gyrus

elevated ridge (outward fold) of the surface of the cerebral cortex

sulcus

shallow groove (inward fold) in the surface of the cerebral cortex

fissure

deep groove (inward fold) in the surface of the cerebral cortex

what two structures are separated from each other by the longitudinal fissure

the cerebral hemispheres along the midline

three basic regions of each cerebral hemisphere

1. superficial cerebral cortex of grey matter

2. internal white matter

3. basal nuclei, islands of grey matter located within the white matter

cerebral cortex

• “executive suite” of the nervous system

• composed of grey matter and lacks any fibre tracts

• contains three kinds of functional areas (motor, sensory, and association)

motor areas of the cerebral cortex

control voluntary movement

the primary motor cortex is located in the pre central gyrus of the _____ lobe of each hemisphere

frontal

the ______ primary motor cortex controls muscles on the right side of the body

left

the ____ cortex helps plan movements

premotor

____ area is a motor speech area that lies anterior to the inferior region of the premotor area

Broca’s

the ____ areas of the cerebral cortex provide for conscious awareness of sensation

sensory

the largest parts of the somatosensory homunculus are the face (especially the lips) and the _______

fingertips

the primary somatosensory cortex is located in the postcentral gyrus of the _______ lobe of each hemisphere

temporal

the _____ primary somatosensory cortex receives input from the right side of the body

left

the somatosensory ______ cortex integrates sensory inputs to produce an understanding of an object being felt

association

regions of the cortex involved in vision are located in the ______ lobe of each hemisphere

occipital

the _____ cortex, a region involved in perceiving taste stimuli, is located in the insula of each hemisphere

gustatory

________ association areas receive inputs from multiple senses and send outputs to multiple areas

multimodal

the ________ association area is involved with intellect, complex learning abilities, recall, and personality

anterior

lateralization

specializations on each side for certain functions

which side of the brain has more control over language abilities

left

a bundle of axons in the central nervous system is called a _____

tract

association fibres

connect different parts of the same cerebral hemisphere

commissural fibres

connect corresponding areas of the two cerebral hemispheres

projection fibres

connect the cerebrum to lower parts of the CNS

the largest commissure is the _________ located deep within the longitudinal fissure

corpus callous

a collection of neuron cell bodies in the CNS is called a ________

nucleus

three structural components that most anatomists agree are included in the basal nuclei of each cerebral hemisphere

1. caudate nucleus

2. putamen

3. globus pallidus

basal nuclei function

monitor the intensity of movements

thalamus function

• plays a key role in mediating sensation, motor activities, cortical arousal, learning, and memory

• the gateway to the cerebral cortex

hypothalamus function

• main visceral control centre of the body and is vitally important to overall body homeostasis

• regulates the autonomic nervous system and endocrine function

• initiates physical responses to emotions

• regulates body temp, food intake, water balance, thirst, sleep wake cycles

epithalamus functions

• includes the pineal gland, which secretes melatonin

• along with the hypothalamus, the epithalamus helps regulate sleep-wake cycle

midbrain functions

• contains the substantia nigra and the red nucleus

• contains the corpora quadrigemina, which control visual and auditory startle reflexes

pons functions

• contains the middle cerebellar peduncles that connect with the cerebellum dorsally

• contains nuclei from which the trigeminal, abducens, and facial nerves issue

medulla oblongata functions

• contains automatic centres that regulate respiration, heart rate, and blood pressure

• the location of the pyramids, which contain the pyramidal (corticospinal) tracts

• contains the inferior olivary nuclei that relay sensory information about muscle stretch to the cerebellum

cerebellum function

involved in producing smooth, coordinated skeletal muscle activity by monitoring the difference between expected/actual result of a motor command

location of the cerebellum relative to the brain stem and the cerebrum

the cerebellum is dorsal (posterior) to the pons/medulla oblongata and inferior to the occipital lobes of the cerebrum

which of the following connects the cerebellum to the brain stem

cerebellar peduncles

functional brain system def

network of neurons that work together but span relatively large distances in the brain, so they cannot be localized to specific regions

functions of limbic system

• mediates emotional response

• involved in memory processing

functions of reticular formation

• keeps the cerebral cortex conscious and alert

• filters out unimportant sensory inputs

which areas work together to form a single language implementation system that analyzes incoming and produces outgoing language

• basal nuclei

• Broca’s area

• Wernicke’s area

the _________ and surrounding ___________ cortical areas are required for memory consolidation; these structures communicate with the thalamus and prefrontal cortex

hippocampus / temporal

two stages of declarative memory

1. STM (working memory): allows memorization of a few units of information for a short period of time

2. LTM: allows memorization of potentially limitless amounts for long periods of time

three factors that influence the transfer of information from STM to LTM

1. emotional state

2. rehearsal

3. association

four ways the delicate brain is protected

1. bone

2. meninges

3. cerebrospinal fluid

4. blood brain barrier

dural septa role

folds of the dura mater that subdivide the cranial cavity; limit excessive movement of the brain within the cranium

impermeable _________ between capillary cells are a major component of the blood brain barrier

tight junctions

the blood brain barrier blocks the passage of _____ - soluble molecules

water

the ______________ of the endothelial cells forming the blood brain barrier contains enzymes that destroy certain chemicals that would otherwise activate brain neurons

basement membrane

small nonessential amino acids and ________ ions are actively pumped from the brain across the capillary endothelium

potassium

the blood brain barrier is _________ in some areas surrounding the third and fourth ventricles

absent

cerebrospinal fluid forms as a filtrate from blood plasma at choroid plexuses that hang from the roof of each __________

ventricle

each choroid plexus is a knot of porous ___________ from which fluid continuously filters; a single later of __________ cells lines each ventricle and processes the filtered fluid to form the CSF

• capillaries

• ependymal cells

the beating of long ______ on these cells helps to circulate the CSF; CSF flows from the two ________ ventricles into the third ventricle via the inter ventricular foramina, and then through the cerebral ________ into the fourth ventricle

• cilia

• lateral

• inter ventricular

• aqueduct

some CSF continues down the central canal of the spinal cord, but most of enters the ____________ space via the median and lateral _________ in the walls of the fourth ventricle; in this space, CSF bathes the outer surfaces of the brain and spinal cord

• central

• subarachnoid

• apertures

CSF returns to the blood in the dural venous sinuses via the arachnoid _________

granulations

the spinal cord extends from the ___________ of the occipital bone to the first or second __________ vertebra

foramen magnum / lumbar vertebra

what is the overall function of the spinal cord

provides a two way conduction pathway to and from the brain and serves as a major reflex centre

what is the name of the cone shaped inferior end of the spinal cord

conus medullaris

wider part of the spinal cord where the nerves serving the upper limbs arise

cervical enlargement

lumber puncture is a procedure in which CSF is removed from the ______________ for diagnostic testing

subarachnoid space

why is a lumbar puncture usually performed below L3

in order not to endanger the spinal cord, which typically ends between L1 and L2

______ neurons whose cell bodies are in the spinal cord grey matter are multipolar

all

the cell bodies of ________ make up the dorsal horns

interneurons

the ventral horns consist mostly of cell bodies of _______ motor neurons

visceral

the ventral horns consist mostly of cell bodies of ______ motor neurons

somatic

the cell bodies of sensory neurons are located in the _______ root ganglia

dorsal

_______ input from peripheral receptors reaches the spinal cord via the dorsal roots

sensory

interneurons receive input from somatic and visceral _______ neurons

sensory

motor output from the spinal cord travels through the _______ roots to reach effectors

ventral

ascending pathways conduct _________ (sensory or motor) impulses to the brain

sensory

descending pathways conduct ___________ (sensory or motor) impulses downward away from the brain

motor

two neurons involved in motor pathways

upper/lower motor neurons

which of the neurons named in the previous question directly innervates the skeletal muscles

the lower motor neurons

ascending pathways typically involve chains of three successive neurons, which ones are they

first, second, third-order neurons

which of those are sensory neurons? interneurons?

first-order neurons are sensory; second and third are interneurons

which pathway

1. transmits impulses via the thalamus to the sensory cortex for conscious interpretation

2. decussated (crosses over) at the level of the spinal cord

spinothalamic pathway

which tract originates from the motor cortex of the cerebrum

pyramidal (corticospinal) tract

which tract transmits information regarding pain and temp to the opposite side of the brain

lateral spinothalamic tract