Central Nervous System Flashcards
The CNS consists of the ____ and ___ ____
Brain and Spinal cord
regions of the brain
Cerebrum – divided into two central hemispheres
Diencephalon
Brain stem
Cerebellum
are paired (left and right) superior parts of the brain
Includes more than half of the brain mass
The surface is made of ridges (gyri) and grooves (sulci)
cerebral hemispheres
Three main regions of cerebral hemisphere
Cortex (gray matter)
White matter
Basal nuclei (deep pockets of gray matter)
Receives impulses from the body’s sensory receptors
Pain, temperature, light touch
Located in parietal lobe posterior to central sulcus
Sensory homunculus is a spatial map
Left side of the primary somatic sensory area receives impulses from right side (and vice versa)
Primary somatic sensory area
Sends impulses to skeletal muscles
Located in frontal lobe
Motor neurons form corticospinal (pyramidal) tract, which descends to spinal cord
Motor homunculus is a spatial map (see previous slide)
Primary motor area
Cerebral areas involved in special senses
Visual area (occipital lobe) Auditory area (temporal lobe) Olfactory area (temporal lobe)
Involved in our ability to speak (vocalize words)
Usually only in left hemisphere
Broca’s Area - Frontal Lobe
Higher intellectual reasoning and social behavior
Anterior association areas
Recognizing patterns and faces; blending all inputs into an understanding of the “whole situation”
Posterior association areas
islands of gray matter buried within the white matter
Regulates the information coming from the primary motor cortex going to the thalamus and then spinal cord
Basal nuclei (ganglia)
Layers of the cerebrum
____ matter—outer layer in the cerebral cortex; composed mostly of neuron cell bodies
____ matter—fiber tracts deep to the gray matter
____ _____ connects hemispheres
Grey
White
Corpus Collosum
Parietal lobe - responsible for:
Sensory processing (somatic) – pain, cold, light touch, position
Temporal Lobe responsible for
Temporal – receptive area (hearing, smell)
Wernicke’s centre (speech comprehension)
Occipital Lobe is responsible for
Occipital – vision interpretation
Separates frontal lobe from temporal lobe
Lateral sulcus - Separates frontal lobe from temporal lobe
Separates frontal lobe from parietal lobe
Contains primary motor cortex (anterior) – sends motor impulses to periphery – in frontal lobe
Contains primary sensory cortex (posterior) - receives impulses from peripheral sensory receptors – in parietal lobe
Central Sulcus
- Separates parietal lobe from occipital lobe
Parieto-occipital sulcus
Cerebral areas involved in special senses
Gustatory area (taste) Visual area Olfactory area (smell) Hearing / speech areas Auditory area Broca’s area
Sits on top of the brain stem Enclosed by the cerebral hemispheres Made of three parts Thalamus Hypothalamus Epithalamus
Diencephalon
Relay station for sensory impulses
Transfers impulses to the correct part of the cortex for localization and interpretation
Thalamus
Under the thalamus Important autonomic nervous system center Helps regulate body temperature Controls water balance Regulates metabolism Houses the limbic center for emotions Regulates the nearby pituitary gland
Hypothalamus
Houses the pineal body (an endocrine gland)
Includes the choroid plexus - CSF
Epithalamus
Parts of the Brain Stem include
Parts of the brain stem
Midbrain
Pons
Medulla oblongata
Attaches to the spinal cord
Composed mostly of tracts of nerve fibers to convey ascending and descending impulses (between cerebrum and spinal cord)
Also contains visual and auditory reflex centers
Midbrain
Mostly composed of fiber tracts
Includes nuclei involved in the control of breathing
Pons
The lowest part of the brain stem - merges into the spinal cord Contains critical control centers Heart rate control Blood pressure regulation Breathing Swallowing Vomiting
Medulla Oblongata
Diffuse mass of gray matter along the brain stem
Involved in motor control of visceral organs
Reticular activating system (RAS)
Plays a role in awake/sleep cycles and consciousness
Filter for incoming sensory information
Reticular Formation
Coordinates complex somatic (motor) patterns from cerebral cortex
Adjusts postural muscles to maintain balance
Programs and fine-tunes movements
Cerebellum
Thick fibrous connective tissue that covers the brain and spinal cord
Meninges
space between the dura and the skull – contains arteries
Epidural space
outmost layer of meninges, thick, attaches to the skull
Dura matar
space between the dura and the brain – contains veins
Subdural space
middle membrane, thin, spider web in appearance – tight to the brain
Arachnoid
below the arachnoid – contains capillaries
Subarachnoid Space –
inner most meninges layer, closely follows contours of the brain
Pia Matar
Similar to blood plasma composition (produced by ependymal cells)
Clear, colorless, contains sugar, no WBC’s or RBC’s
Forms a watery cushion to protect the brain
Circulated in arachnoid space, ventricles, and central canal of the spinal cord
Cerebrospinal fluid
Blood Brain Barrier
Barrier formed by endothelial cells of the brain’s capillaries which form continous tight junction – creating a barrier to certain dyes, medications and antibiotics – allowing in glucose, water and amino acids
Blood Brain barrier does not keep out substances including
Useless against some substances
Fats and fat soluble molecules, respiratory gases, alcohol, nicotine, anesthetics
