Module 2: Nervous System (Part 2) Flashcards
Brain divisions (4)
1) Cerebrum
2) Brainstem
3) Diencephalon
4) Cerebellum
Ventricles (2)
1) Cavities within the brain that are filled with CSF
2) Four ventricles include the two lateral ventricles, third ventricle and fourth ventricle, which drains into the central canal of the spinal cord
Meninges
Three layers of connective tissue membranes that cover and protect CNS organs and enclose CSF
Dura mater
Leathery, double-layered outer meninx
Subdural space
Space below the dura mater and above the arachnoid space
Arachnoid meninx
Loose layer separated from the dura mater by the subdural space
Subarachnoid space (2)
1) Beneath the arachnoid meninx
2) Filled with CSF and contains blood vessels
Pia mater meninx
Thin connective tissue tightly attached to the brain
Cerebrospinal fluid (CSF)
1) Special fluid formed in the walls of the ventricles from blood plasma by permeating through the CHOROID PLEXUS
2) Cushions the brain and spinal cord by providing buoyancy
3) Circulates through the ventricles and into the subarachnoid space, bathing brain in fluid
Blood-brain barrier (3)
1) Diffusion barrier that prevents most particles from entering the CNS tissue, keeping the brain and spinal cord separate from general blood circulation
2) Formed by astrocyte glial cells
3) Creates a stable chemical environment for the nervous system
Cerebrum
1) Foremost part of brain, comprising 83% of brain mass
Cerebral hemispheres (2)
1) Left and right masses of the cerebrum, separated by MEDIAN LONGITUDINAL FISSURE
2) Left cerebral hemisphere controls right side of the body and right cerebral hemisphere controls left side of the body
Cerebral cortex (2)
1) Outer portion of the cerebral hemispheres
2) Highly convoluted and gray in color
Corpus callosum
White nerve fibers that connect cerebral hemispheres so they can communicate with each other
Gyri
Raised ridges of tissue in cerebral cortex
Sulci
Shallow grooves in cerebral cortex that separate gyri
Right and left central sulcus
Central sulci that go from top to bottom of brain
Fissures
Deeper grooves that separate large region of the brain
Transverse fissure
Separates cerebrum from the cerebellum
Four lobes of the brain (4)
Frontal lobe (anterior)
Parietal lobe (posterior top)
Occipital lobe (posterior)
Temporal lobe (sides)
Frontal lobe
Controls higher level executive functions such as reason and decision making
Parietal lobe
Receives sensory information from receptors in the mouth for taste and located in the skin, such as those for touch, pressure and pain
Occipital lobe
Interprets visual input
Temporal lobe
Sensory areas for hearing and smelling
Primary areas of each lobe
Receive or send information for one type of sensory or motor information
Primary motor cortex
Controls voluntary motor movements for all parts of the body
Primary sensory cortex
Parietal lobe receives sensory information from the same parts of the body
Association areas of each lobe (3)
1) Act mainly to integrate more than one type of sensory information for purposeful action
2) Each lobe contains an association area which receives information from the other lobes and integrates it into higher, more complex levels of consciousness
3) Examples include intellect, artistic/creative ability, learning and memory
Broca’s area
Located in the frontal lobe, is responsible for speech PRODUCTION
Wernicke’s area
Located in temporal lobe, is responsible for speech COMPREHENSION
Detailed graph of lobes and primary/association areas
Consciousness and the cerebrum (2)
State of being awake and aware of a person’s surroundings
Cerebrum is portion of brain that governs intelligence reasoning and higher level thinking and can override “lower parts of brain”
Parts of the brainstem (3)
1) Midbrain
2) Pons
3) Medulla oblongata
Medulla oblongata (3)
1) Lies between the spinal cord and pons and is anterior to the cerebellum
2) contains vital centers for regulating heartbeat, breathing and vasoconstriction
3) Contains reflex centers for vomiting, coughing, sneezing, hiccuping and swallowing
Vasoconstriction
Constriction of the blood vessels involved in the regulation of blood pressure
Pons (3)
1) Contains bundles of axons traveling between the cerebellum and the rest of the CNS
2) Works with medulla to regulate the breathing rate
3) Contains reflex centers concerned with head movements in response to visual and auditory stimuli
Midbrain
1) Acts as a relay station for tracts passing between the cerebrum and spinal cord or cerebellum
2) Has reflex centers for higher-level reflexes involving visual, auditory and tactile responses
Superior and inferior colliculi
1) Located on posterior portion of midbrain
2) Control reflexes for the head and neck in response to a sudden visual or auditory stimulus
Diencephalon
Portion of the brain that contains the hypothalamus, thalamus, and epithalamus
Hypothalamus (5)
1) Forms the floor of the third ventricle
2) Responsible for homeostasis of the body environment
3) Contains centers for regulating basic body functions, such as hunger, sleep, thirst, body temp, water balance and blood pressure
4) Controls pituitary gland
5) Link between the nervous and endocrine systems (through neurosecretory cells)
Pituitary gland
Regulates the body hormones of the endocrine system
Thalamus (4)
1) In the roof of the third ventricle
2) Central relay station for sensory impulses traveling upward from other parts of the body and the brain to the cerebrum
3) Receives information, filters out unimportant information, and directs it to appropriate region of the cerebrum
4) Doesn’t receive smell
Epithalamus
1) Forms the roof of the third ventricle
2) Mostly composed of the PINEAL GLAND, which secretes melatonin, which controls the wake-sleep cycle
Cerebellum (6)
1) Located inferiorly and posteriorly to the brain
2) Two hemispheres with deep fissures and three lobes each
3) Often called the “mini brain”
4) OUTER gray matter and INNER white matter, opposite of spinal cord
5) Coordinates body movements by relaying information to the cerebral motor cortex
6) Also involved in maintaining balance, controlling certain eye movements, maintaining normal muscle tone and maintaining posture
Muscle tone (2)
1) The degree at which muscles remain partially contracted while at rest
2) Governed by the cerebellum to keep bones and joints in place
Anterior lobes and posterior lobes of cerebellum
Receive information from the body trunk and influence the motor activities of the trunk, shoulder and pectoral girdle muscles
Vermis (cerebellum) (2)
1) Intermediate portion
2) Coordinates limb movements
Cerebellar peduncles (cerebellum)
Connect cerebellum to other parts of brain
Ataxia (disorder of Cerebellum)
Lack of voluntary muscle motor coordination
Limbic system
1) Just beneath cerebral cortex and contains neural pathways that connect portions of the frontal lobes, temporal lobes, thalamus and hypothalamus
2) Involves portions of conscious and unconscious brain
Cingulate gyrus (limbic system) (2)
1) Located deep to the cerebrum
2) Connects different lobes of the cerebrum
Hippocampus (limbic system) (2)
1) Involved in retrieval and storage of memories
2) Memories not stored in hippocampus itself. Hippocampus acts as a direction center
Amygdala (limbic system)
Smaller portion of limbic system that is involved in emotions such as rage and anger
Fornix (limbic system)
Bundle of nerve fibers that serves as a connection to the hippocamus
Mamillary bodies (limbic system)
Contain fibers that project into the thalamus and assist with the memory of smell
Limbic system and emotions (2)
1) Include rage, pain, pleasure, sorry and rewards/consequences
2) Known as our “feeling brain”
Short term memory (limbic system)
Example - recall 7-digit phone number
Long-term memory (limbic system)
Ability to recall events of the day
Memory
1) Not stored in one area of the brain
2) Hippocampus acts as memory center and assists in storage and retrieval of memories from the cortex
Why are emotionally charged events so vivid in our memories?
Because the limbic system communicates with all sensory areas and accounts for ability of a sensory stimulus to awaken a complex memory
Basal ganglia (also called basal nuclei) (limbic system) (2)
1) Masses of gray matter that lie deep within each hemisphere of the cerebrum
2) Responsible for working with the cerebellum to regulate planning motor movements and motor learning
3) Slows and controls precise movements through inhibition of cerebral cortex
Components of basal ganglia (3)
1) Putamen
2) Caudate nucleus
3) Globus pallidus
Parkinson’s disease
1) Disease of the basal ganglia
2) Apraxia, difficulty with motor planning, is symptom of the disease
3) Apraxia causes rigid movements and difficulty executing a motor plan
Spinal cord (3)
1) 17 inches in length
2) Protected by the surrounding vertebral column
3) Extends from brainstem to first lumbar vertebra
Conus medullaris (spinal cord)
Official termination point of spine at first lumbar vertebra
Cauda equina (spinal cord)
Collection of nerve roots that extends BEYOND the lumbar 1 termination of the spinal cord, which end at the coccyx