Unit 12: Key Terms
Central Nervous System (CNS)
Includes brain and spinal cord, involved in movement interpreting sensory info, maintaining homeostasis, and functions relating to mind.
Meninges
Membranes that protects brain and spinal cord, dura mater, arachnoid mater, pia mater
Dura Mater
Outer layer, tough, dense, connective tissue
Arachnoid Mater
middle layer, web-like, subarachnoid space contains cerebrospinal fluid (CSF)
Pia Mater
The inner layer, attached to the surface of the brain and spinal cord, blood vessels and nerves, nourishes CNS
Cerebrospinal Fluid
produced in 4 ventricles
Ventricles
are interconnected cavities within cerebral hemispheres and brain stem, continues with the central canal of the spinal cord, filled with CSF
The 4 ventricles
2 lateral (called 1st and 2nd ventricles), third ventricle, fourth ventricle
Cerebral Spinal Fluid
nutritive and protective, helps maintain stable ionic concentrations in the CNS
Brain
soft, whitish-gray organ, anatomically continuous with spinal cord, resides in cranial cavity
Cranial Cavity
directly or indirectly controls most of body's functions
Cerebrum
structure responsible for higher mental functions
Sulci
shallow grooves on surface of cerebrum
Gyri
elevated ridges found between sulci
Gross anatomical features of the cerebrum
together-> sulci and gyri increase surface area of brain, maximize limited space within confines of skull
Frontal lobes
most anterior, neurons are responsible for planning and executing movement and complete mental functions such as behavior, conscience, and personality
Parietal Lobes
just posterior to frontal lobes, neurons are responsible for processing and integrating sensory information and function in attention
Temporal lobes
lateral surfaces of each cerebral hemisphere, neurons are involved in hearing, language, memory, and emotions
Occipital lobes
posterior aspect of each cerebral hemisphere, neurons process all information related to vision.
Insulas
deep underneath lateral fissures, neurons are currently thought to be involved in functions related to taste and viscera (internal organs)
Fissures
deep grooves on surface of cerebrum
Longitudinal fissure
long deep groove, separates left and right cerebral hemispheres
Gray Matter: Cerebral cortex
functionally most complex part of cortex: covers underlying cerebral hemispheres
Neocortex
most of the cerebral cortex is this, most recently involved region of the brain, with a huge surface area
Neurons in cortex
interneurons
Cerebral white matter
contains myelinated nerve fibers
Commissural fibers
connect right and left hemispheres, corpus callosum
Diencephalon
between cerebral hemispheres and above the brainstem, surrounds the 3rd ventricle, composed of gray matter
Thalamus
main entry route of sensory data into the cerebral cortex consists of 2 egg-shaped regions of gray matter: 80% of the diencephalon, and thalamic nuclei recieve afferent fivers from many other regions of the nervous system excluding the sense of smell
Hypothalamus
collection of nuclei anterior and inferior to the larger thalamus, neurons perform several vital functions critical to survival, secretes hormones, and affect function of pituitary gland
Mammillary bodies
connect hypothalamus with limbic system, memory regulation and behavior
Cerebellum
the posterior and inferior portion of the brain, interactions between regions together coordinate movement, divided into two cerebellar hemispheres
Transverse fissure
separates cerebrum from cerebellum
Falx cerebelli
two hemispheres are separated by this
Cerebellar cortex
the outer layer of gray matter, extremely folded
Arbor vitae
branching white matter, resembles tree branches
Brainstem
one of oldest components of brain, vital to immediate survival, 3 subdivisions
3 subdivisions of the brainstem
superior midbrain, middle pons, inferior medulla oblongata
Brainstem control/function in:
basic homeostatic functions (heart rate and breathing rhythms), reflexes, movement, sensation, and maintaining alertness
Midbrain
short section of brainstem, lies between diencephalon and pons, contains bundles of fibers that join lower parts of brainstem and spinal cord with higher part of brain
Midbrain: Cerebral peduncles
bundles of nerve fibers
Midbrain: Corpora quadrigemina
centers for visual and auditory reflexes, superior and inferior colliculi
Pons
rounded bulge on underside of the brainstem, between the midbrain and medulla oblongata, relays nerve impulses between the medulla oblongata and cerebrum, relays impulses from cerebrum to cerebellum, helps regulate the rhythm of breathing
Medulla oblongata
enlarged continuation of spinal cord, conducts ascending and descending impulses between brain and spinal cord, contains cardiac, vasomotor, and respiratory control centers, injuries are often fatal
Blood-brain barrier
protective safeguard, separates CSF and brain ECF from chemicals and disease-causing organisms sometimes found in blood plasma, consists mainly of simple squamous epithelia cells (endothelial cells) of blood capillaries, their basal laminae and astrocytes
Spinal cord
slender column of nervous tissue continuous with brain and brainstem, extends downward through vertebral canal, consists of 31 segments, each given rise to a pair of spinal nerves
Structure of the spinal cord
longitudinal section: cervical enlargement, lumbar enlargement, conus medullaris, cauda equina, filum terminale
Functions of the spinal cord
center for spinal reflexes, conduit (pathway) for impulses to and from the brain
Receptor
the end of a dendrite or a specialized receptor cell in a sensory organ, sensitive to a specific type of internal or external change
Sensory neuron
dendrite, cell body, and axon of a sensory neuron conducts an impulse from the receptor into the brain or spinal cord
Interneuron
dendrite, cell body, and axon, of a neuron within the brain or spinal cord, serves as processing center: conducts an impulse from the sensory neuron to its synapse with a motor neuron
Motor neuron
dendrite, cell body, and axon of a motor neuron conducts an impulse from the brain or spinal cord out to the synapse with an effector
Effector
a muscle or gland, responds to stimulation by the motor neuron and produces the reflex or behavioral action