Chapter 4- Anatomy of the Nervous System Flashcards
Central Nervous System
Brain and Spinal Cord
Peripheral Nervous System
nerves outside the brain and spinal cord
part of the PNS is somatic nervous system- consists conveying messages from sense organs to the CNS and from CNS to the muscles
What are the limbs controlled by?
Somatic Nervous system
Autonomic Nervous System
controls the heart, intestines and other organs . Has cell bodies in the brain, or spinal cord, in clusters along the spinal cord
What is the spinal cord?
Part of the CNS within the spinal column, communicates with all the sense organs and muscles except those in the head
Bell- Magendie Law
entering dorsal roots( axon bundles) carry sensory information, and exiting ventral roots carry motor information
Dorsal root ganglia
clusters of neurons outside spinal cord ( contain cell bodies of sensory neurons)
What is the difference between nucleus and ganglion?
N- clusters inside the spinal cord
G- neuron cluster outside the CNS
Gray Matter
in center of spinal cord and the brain- densely packed with cell bodies and dendrites
White Matter
Consists mostly of myelinated axons, carries information from the gray to the brain or other areas of the spinal cord
If the spinal cord is cut at a given segment…
brain loses all sensations from that segment and below. Also loses motor control over all parts of the body served by that segment and the lower ones
Autonomic Nervous Systems
Sends and receives messages to regulate the automatic behaviors of the body ( heart rate, bp, digestion, respiration)
Sympathetic Nervous System & Parasympathetic systmem
What neurotransmitter does the SNS use?
Mostly norepinephrine ( adrenaline)
Sympathetic Nervous System
network of nerves that prepare organs for vigorous activity.
Fight or Flight, comprised of ganglia on the left and right side of the spinal cord. Sympathetic ganglia are closely linked and often act as single system in sympathy with one another
Parasympathetic Nervous System
facilitates vegetative, nonemergency responses . Decreases functions increased by the SNS , conserves energy, dominate during relaxed states
What neurotransmitter does the PNS use?
Mostly Acetylcholine
Because system uses two different neurotransmitters…
certain drugs excite or inhibit one system or another
The Hindbrain
consists of medulla, pons and cerebellum
Brainstem
consists of medulla, pons, midbrain and hindbrain. Controls vital reflexes
Medulla
enlarged extension of spinal cord, controls some vital reflexes through cranial nerve, located just above the spinal cord
Pons
lies anterior and ventral to medulla and contains nuclei for several cranial nerves
Contains the Reticular Formation- has ascending and descending portions
Raphe system- sends axons to much of the forebrain, modifying brain’s readiness to respond to stimuli
What does the Reticular Formation Ascending portion do?
sends output to much of cerebral cortex, selectively increases arousal and attention
What does the Reticular Formation descending portion do?
helps control motor axons of spinal cord
Cerebellum
large hindbrain structure with many deep folds ( 70% of all neurons in your system )
contributes to control of movement, balance and coordination, helps people shift attention back and forth between auditory and visual stimuli
Cerebellum size= more dexterity
Substania Nigra
gives rise to dopamine-containing pathway that facilitates readiness for movement, death of neurons in this area is cause for Parkinson’s disease
Forebrain
most anterior and most prominent part of mammalian brain, consists of right and left hemispheres, each one organized to receive sensory information and to control muscles
Outer portion of the forebrain is
Cerebral cortex ( more folds= surface area for neurons)
houses the limbic system- interlinked structures that form border around brainstem, important for motivations and emotions, drives aggression and memory )
Diencephalon of the forebrain…
consists of thalamus and hypothalamus
Thalamus
pair of structures in center of forebrain. most sensory information goes first to thalamus, which processes it and sends output to cerebral cortex except for olfactory information
helps focus attention on particular stimuli
Hypothalamus
small area near base of the brain just ventral to thalamus
has widespread connections with rest of forebrain and the midbrain, conveys messages to pituitary gland, altering its release of hormones, associated with drives
If the hypothalamus is damaged?
loss of sense of hunger and sexual motivation
Pituitary gland
an endocrine gland attached to base of hypothalamus that receives messages from hypothalamus and then synthesizes and releases hormones into bloodstream
Basal Ganglia
group of cortical structures lateral to thalamus
contains caudate nucles, putamen and globus pallidus
has subdivision that exchange information with different parts of cerebral cortex, most connections are with frontal areas of cortex.
Responsible for planning sequences of behavior and for certain aspects of memory and emotional expression, attention, motor movement and language planning
Hippocampus
large structure between thalamus and cerebral cortex. critical for learning and memory, especially for forming new memories and temporary storage . critical for encoding episodic memories
The ventricles
four fluid filled cavities within the brain, flow of CSF through ventricles provides “ cushioning” for the brain, reserved for hormones and nutrition for the brain and spinal cord
Meninges
membranes that surround brain and spinal cord, the brain has no pain receptors but these do
Cerebral Cortex
divided into two halves, joined by the corpus callosum.
Divided into four lobes: Occipital, Parietal, Temporal and Frontal
Parietal Lobe
lies between occipital lobe and the central sulcus, contains postcentral gyrus ( main target for touch sensations and information from muscle-stretch receptors and joint receptors )
Important for numbers and spatial information
Temporal Lobe
lateral portion of each hemisphere near the temples
primary target for auditory information, essential for understanding spoken language but not for producing it. also contribute to complex aspects of vision, perception of movement and recognition of faces.
They also play a part in emotional and motivational behaviors
Kluver Bucy syndrome associated with temporal lobe damage
Frontal Lobe
extends from central suclus to anterior limit of brain
contains primary motor cortex and prefrontal cortex
precentral gyrus - specialized for control fine movement
Prefrontal cortex-
recieves information from all sensory systems, but it not primary target for any one
responsible for higher functions such as abstract thinking, planning and working memory
What is the binding problem?
how visual, auditory and other areas of the brain produce a perception of a single object
Ablation
removal of brain area
lesion
damage to brain area
Sterotaxic instrument
device for precise placement of electrodes in brain
Sham lesion
lesion produced in control group
Electrocephalograph
records electrical activity of the brain through electrodes applied to the scalp. good temporal resolution
Optogenetics
a technique that allows researchers to turn on activity in targeted neurons by a device that shines a laser within the brain
Magentoencephalograph
measures faint magnetic fields generated by brain activity . can localize source of signal better than EEG
fMRI
measures oxygen consumption in the brain
Einstein had an unusually large
parietal lobe, useful for numbers and spatial information
