Chapter 4: Neurophysiology, Neurotransmitters, and the Nervous System: Part II Neuroanatomy

brain and spinal cord are

encased in bone

human skull has how many bones

22 - 8 cranial, 14 facial

how many vertebrae at birth

33 - 7 cervical. 12 thoracic, 5 lumbar, 5 sacral (fused in adults) and 3-5 coccygeal (fused/tailbone)

how many vertebrae in adults

24 plus fused sacrum

meninges

set of thin membranes that hold the brain and spinal cord in place and act as a protective buffer

parts of nervous system

central and peripheral

cns

brain and spinal cord

pns

motor and sensory neurons

brain

receives and processes sensory information, imitates responses, stores memories generates thoughts and emotions

spinal cord

conducts signals to brain, controls reflex activities

motor neurons

cns to muscles and glands

sensory neurons

sensory organs to cns

2 parts to motor neurons

somatic ns and autonomic ns

somatic ns

controls voluntary movements

autonomic ns

controls involuntary responses

2 parts of autonomic nervous system

sympathetic ns and parasympathetic ns

sympathetic ns

fight or flight

parasympathetic ns

rest or digest

dura mater consist of

outer and inner fibrous layers

outer layer of dura mater

fused to periosteum of cranial bones

dural venous sinuses

collect blood from veins of the brain

three layers of cranial meninges

dura mater, arachnoid mater, pia mater

dura mater consists of

endosteal layer, dural sinus, meningeal layer

arachnoid mater consists of

arachnoid membrane, subarachnoid space, arachnoid trabeculae

pia mater is

bound to the surface of the brain by astrocytes

parts of ventricular system

lateral ventricles, inter ventricular foramen, third ventricle, cerebral aqueduct, fourth ventricle, central canal

CSF secreted

by choroid plexus (network of specialized ependymal cells and bv)

CSF fills

spaces and canals (ventricles, central canal of spinal cord, subarachnoid space of meninges)

csf provides

medium through which nutrients, hormones, etc access brain cells; dispose of waste products

csf protects

brain and spinal cord by acting as a buffer (liquid buffer or cushion to absorb internal and external forces)

CSF is first

secreted by choroid plexus in each lateral ventricle

CSF flows through

interventricular formina into third ventricle

choroid plexus in third ventricle

adds more CSF

CSF flows down

cerebral aqueduct to fourth ventricle

choroid plexus in fourth ventricle

adds more CSF

CSF flows out

two lateral apertures and one median aperture

CSF fills what space

subarachnoid space and bathes external surfaces of brain and spinal cord

at arachnoid villi

CSF is reabsorbed into venous blood of dural venous sinuses

capillary in brain vs general capillary

carrier mediated transport as has tight junctions/no pores, where general capillaries have pore passage

what do brain capillaries have that general ones do not

astrocytes

planes of sectioning

sagittal/median, coronal/frontal, transverse/horizontal

neuraxis

imaginary line drawn through central of length of CNS from bottom of spinal cord to front of forebrain

coronal section

is cut in a vertical plane, yielding frontal view

horizontal section

dorsal view - looking down on the brain from above

sagittal section

cut lengthways from front to back and viewed from the side - midsagittal plane divides brain into symmetrical halves, a medial view

contralateral

referring to structures or functions on opposite sides of the body or brain.

ipsilateral

referring to structures or functions on the same side of the body or brain.

white matter

composed of myelinated axons that form connections between different brain regions, facilitating communication.

grey matter

composed of neuronal cell bodies, dendrites, and unmyelinated axons, primarily involved in processing and integrating information.

afferent

referring to sensory pathways that carry signals toward the central nervous system from sensory receptors.

efferent

referring to motor pathways that transmit signals away from the central nervous system to muscles and glands.

nucleus

a cluster of neuronal cell bodies located in the central nervous system, serving a specific function in processing information.

ganglion

a cluster of neuronal cell bodies located in the peripheral nervous system, involved in transmitting signals between the central nervous system and the rest of the body.

tract

a bundle of axons in the central nervous system that connects different regions and carries signals.

nerve

a bundle of axons in the peripheral nervous system that transmits signals between the central nervous system and other body parts.

major divisions of brain

forebrain, midbrain, hindbrain

forebrain divisions

telencephalon and diencephalon

telencephalon divisions

cerebral cortex, basal ganglia, limbic system

diencephalon divisions

thalamus and hypothalamus

midbrain divisions

mesencephalon

mesencephalon divisions

tectum and tegmentum

hindbrain dvisions

metencephalon and mylencephalon

metencephalon divisions

cerebellum and pons

mylencephalon divisions

medulla oblongata

cortex

frontal lobe, parietal lobe, occipital lobe, temporal lobe

frontal lobe main role

thinking, planning, voluntary movement

key functions of frontal lobe

voluntary muscle movements (primary motor cortex), decision making and problem solving, planning and organizing behaviour, personality and emotional control, attention and concentration, speech production (Broca’s area)

frontal lobe often called

brain’s executive control center

parietal lobe main role

processing body sensations and spatial awareness

key functions of parietal lobe

touch, pressure, pain and temperature sensation, awareness of body position (proprioception), spatial orientation and navigation, integrating sensory information, hand-eye coordination

parietal lobe helps

you understand where your body is in space

temporal lobe main role

hearing, memory, language understanding

key functions of temporal lobe

auditory processing (hearing), language comprehension (Wernicke’s area), memory formation, recognition of faces and objects, emotional processing

temporal lobe is important for

understanding speech and forming memories

occipital lobe main role

vision

occipital lobe key functions

visual processing (primary visual cortex), interpreting color, shape and motion, visual recognition

occipital lobe is essentially

brain’s visual processing center

what is located along longitudinal fissure of brain

the corpus callosum, connecting the left and right hemispheres

gyri

are the folds and grooves of the brain's surface that increase its surface area and accommodate more neuronal connections.

sulci

the grooves or indentations on the surface of the brain that separate the gyri.

central sulcus

is a prominent groove that separates the frontal lobe from the parietal lobe in the brain, playing a crucial role in sensory and motor functions.

what are on the ventral and dorsal sides of central sulcus

precentral gyrus and postcentral gyrus

precentral gyrus is the

primary motor cortex

postcentral gyrus is the

primary somatosensory cortex

corpus callosum

largest white matter structure in brain with 200-300 million axonal projections that act as a bridge for interhemispheric communication

primary functions of corpus callosum

coordinating motor, sensory and cognitive information between left and right hemispheres

corpus callosum is composed of

the rostrum, genu, body and splenium

damage or developmental conditions to corpus callosum (

(agenesis of corpus callosum) can result in cognitive impairment, motor challenges and behavioural issues

basal ganglia has

3 distinct nuclei - caudate nucleus, putamen, globus pallidus

striatum

caudate nucleus and putamen - major input center for basal ganglia

when thinking of basal ganglia in terms of a motor system

subthalamic nucleus, substantia nigra

basal ganglia and related nuclei consist of

variety of subcortical cell groups engaged primary in motor control

parkinsons disease

caused by the degeneration of nigrostriatal dopaminergic neurons

symptoms of PD

weakness, tremors, rigidity of limbs, poor balance, difficulty in initiating movements

limbic system

group of interconnected structures that mediate emotions, learning and memory and include the hippocampus and amygala

hippocampus

associated mainly with memory - long term memory

amygdala is

one of two almond shaped groups of nuclei located deep and medially within temporal lobe - it is the integrative center for emotions, emotional behaviour and motivation

massa intermedia

a section of the thalamus that is involved in the relay of sensory information and plays a role in emotional responses.

thalamus has

2 lobes/halves

thalamus consists of

several specialized areas called nuclei - each responsible for processing different sensory or motor impulses from body - send through nerve fibers to an area of cerebral cortex