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79 Cards in this Set

  • Front
  • Back
Stroke
Interruption of blood to the brain that kills brain cells ad causes neurological symptoms.
• 500K strokes/year in the US; 2nd leading cause of death worldwide
Ischemia Stroke
Deficiency of blood flow to the brain by clot or some other constriction or obstruction of a blood vessel
Hemorrhagic stroke
Burst of a blood vessel
• 500K strokes/year in the US;
The Brain:
Nuclei
Groups of neurons - work together
Ipsilateral
Structures that lie on the same side
Contralateral
Structures that lie on opposite sides
Bilateral
One structure lies in each hemisphere
Proximal
Structures are close to one another
Distal
Structures are far from one another
Afferent
Movement toward the brain
• Sensory pathways
Efferent
Movement away from the brain
• Motor pathways
Dorsal Superior
Ventral Inferior
Rostral Anterior
Caudal Posterior
Dorsal Superior: top of brain
Ventral Inferior: bottom of brain

Rostral Anterior: front of brain
Caudal Posterior: back of brain
Nervous System Structure
Central NS: Brain & Spinal Cord
Somatic NS: Cranial & Spinal Nerves
Autonomic NS: Sympathetic & Parasympathetic Divisions
Coronal Section
Cutting the brain in a vertical section. (Gives frontal view.)
Horizontal Section
Cutting the brain in a horizontal section. (Gives dorsal view.)
Sagital Section
Cutting the brain in a vertical section. (Gives medial view.)
4 Ways that the brain and spinal cord are protected: 1
1. Skull protects brain; bony vertebrae protect spinal cord
• CNS is protected by bony encasements, but self-repair is limited
• PNS lacks bony protection > more vulnerable to injury; can renew itself after injury by growing new axons/dendrites
4 Ways that the brain and spinal cord are protected: 2
2. The meninges: triple-layered set of membranes within bony enclosings of CNS
• Dura matter, arachnoid membrane, pia matter
4 Ways that the brain and spinal cord are protected: 3
Cerebrospinal fluid
• Circulates in four ventricles of the brain, spinal column, and within subarachnoid space
• Cushions brain and spinal cord from shock and sudden pressure changes
• Hydrocephalus: Congenital condition which occurs if outflow of CSF is blocked > severe mental retardation and possible death
4 Ways that the brain and spinal cord are protected: 4
• Blood-Brain Barrier: prevents intrusion by chemicals and other blood-borne substances from entering CNS tissues
Blood Vessels of the Skull
• Lie in space between skull and cerebrum; provides blood supply
• Rupture during trauma > bleeding
• Grooves for arteries
Blood Supply
• Brain requires constant oxygen supply - lack of oxygen for few minutes can > brain damage
How many arteries feed the brain and name the two types:
4 arteries up each side of the neck:
• 2 internal carotid arteries
• 2 vertebral arteries
Connect at the base of the brain and enter the skull
> branch off into several smaller arteries that irrigate the brainstem and cerebellum > 3 arteries that irrigate forebrain
3 arteries that irrigate forebrain:
• Anterior Cerebral Artery - irrigates the dorsal
• Middle Cerebral Artery - irrigates the lateral
• Posterior Cerebral Artery - irrigates the ventral
How does the brain form?
• Stem cell (Self-renewal) >
• Progenitor (Progenitor produced) >
• Blast (Neuroblasts and Glioblasts producted) >
• Specialized (Neuro and Glio differntiations) >
Neurons:
Bipolar
Bipolar: simple neuron - axon and dendrite on opposite sides
Neurons:
Somatosensory
Somatosensory: project from sensory receptors > spinal cord, dendrite and axon connected = faster speed of info transmission
Neurons:
Interneurons
Interneurons: are within brain and spinal cord; link up sensory and motor neurons in CNS; many dendrites, branching axon
Neurons:
Motor
Motor: in brainstem, project to facial muscles - in spinal cord to other muscles - all bx passes through them
Glial Cells
All different kinds with different functions
Know Glial Cells and Their Functions in Book!!!
(They are for support)
Know Glial Cells and Their Functions in Book!!!
(They are for support)
Gray Matter
Gray-brown color from capillary blood vessels and neuronal cell bodies
White matter
Axons that extend to form connections with other neurons
Reticular matter
"Net" or mixture of cell bodies and axons - grey and white matter, netlike
Tract/Fiber Pathway
Large collection of axons projecting to or away from a nucleus or layer in the CNS
• Carry info from place to place within the CNS
• Ex. corticospinal/pyramidal tract carries info from cortex to spinal cord
• Ex. Optic tract: information from retna of eye to visual centers in the brain
Nerves:
Fibers and fiber pathways that enter and leave the CNS.
• Ex. auditory nerve, vagus nerve
• After the nerve leaves the CNS, they are called tracts
Origin and development of CNS
Vertebrate > Mammalian > Human
Steps in the development of the brain: Human Brain
Retains most features of other mammalian brains but larger cerebral hemispheres
Human Brain: Forebrain
Neocortex, basal ganglia, limbic system, olfactory bulb, lateral ventricles
Human Brain: Brainstem
Thalamus, hypothalamus, pineal body, third ventricle, tectum, tegmentum, cerebral aqueduct, cerebellum, pons, fourth ventricle, medulla
Cerebral Ventricles
• Hollow pockets filled within the brain filled with CSF
• Numbered 1-4
- Lateral ventricles (first and second)
- Third and fourth ventricles extend into the brainstem and spinal cord
Spinal Cord Structure & Spinal Nerves
• 30 segements
• Cervical
• Thoracic
• Lumbar
• Sacral
Dermatomes
Regions of body surfaces
Dorsal Root
• Strand of afferent fibers entering the spinal cord
• Carries sensory information to the brain
Ventral Root
• Strand of afferent fibers leaving the spinal cord
• Carries motor information to the brain
SC Injuries
Paraplegic: no control over legs
Quadriplegic: cut is higher on cord - unable to use arms or legs
Flexion
Stimulation of pain and temperature receptors in limbs produces flexion - limb turns out and away from injury
Extension
Stimulation of fine touch and muscle receptors > extension
• Extensor reflex - touch part remains in contact with stimulus
Cranial Nerves
• Make connections between the somatic nervous system (SNS) and CNS
• 12 pairs, overseen by the brain
• Can have afferent functions, efferent functions, or both
Cranial Nerves
12 of them - Know what they generally do
What does the vagus nerve do?
What does the Sensory nerve do?
Autonomic Nervous System
Two Divisions:
• Sympathetic
- Arouses the body for action
- "Fight or flight"
- Spinal nerves in the thoracic and lumbar regions are connected to the sympathetic ganglia

• Parasympathetic
- Calms the body
- "Rest and digest"
- Connects with parasympathetic ganglia near target organs
The Brainstem
• Produces more complex movements than does the spinal cord
• Regulates many complex functions
Hindbrain
• Cerebellum
• Recticular Formation
• Pons and Medulla
Cerebellum
• Corrdinates and helps learn skilled movements
• Damage = Equilibrium problems, postural defects, and impairment of skilled motor activity
Recticular Formation
• Maintains general arousal
Pons & Medulla
• Waking, sleeping, respiration, cardiovascular functions, locomotion
• Coughing, sneezing, vomiting
The Midbrain
Two Main Subdivisions
1. Tectum/"roof" - dorsally located - receives sensory info from eyes and ears
2. Tegmentum/"floor" - ventrally located - composed of nuclei related to motor functions
Tectum
Tectum/"roof" - dorsally located
• Receives sensory info from eyes and ears
• Superior colliculi: mediate visually related bx
• Inferior colliculi: mediate many auditory-related bx
• Both colliculi involved in orienting towards movements (i.e., turning head to look at the source of a sound)
Tegmentum
Tegmentum/"floor" - ventrally located
• Composed of nuclei related to motor functions
• Red nucleus: controls limb movements
• Substantia Nigra: important for reward and for initiating movements
• Periaqueductal gray matter: cell bodies - controlling species-specific bx (i.e., sexuall bx) and for modulating responses to pain
Diencephalon (Know This!!!)
• Hypothalamus
• Thalamus
• Epithalamus
Hypothalamus (Know This!!!)
.3% of brain - but involved in almost all aspects of motivated bx, interacts with pituitary gland
Thalamus (Know This!!!)
Largest structure in Diencephalon - "Relay Center" of the brain
• 20 large nuclei which each project to a specific area of the cerebral cortex
• Relays info from sensory systems to their appropriate targets: LGB, MGB, VLP
• Relays information between cortical areas
• Relays info from other forebrain and brainstem regions
Thalamus related:
Lateral Geniculate Body (LGB)
Medial Geniculate Body (MGB)
Ventrolateral Posterior Nucllei (VLP)
Lateral Geniculate Body: receives visual projections
Medial Geniculate Body: receives auditory projections
Ventrolateral Posterior Nuclei: receives touch, pressure, pain, and temperature projections from body
Epithalamus
Pineal gland - secretes melatonin - influences seasonal body rhythms. Involved in hunger and thirst.
Hypothalamus:
Location and what it does
Sits under the Thalamus at the top of the brainstem.
• Controls autonomic nervous system
• Center for emotional response and behavior
Regulates body temp
• Regulates food intake
• Regulates water balance and thirst
• Controls sleep-wake cycles
• Controls endocrine system
Thalamus:
Location and what it does
Sits deep in the brain at the top of the brainstem.
• Called the "gateway to the cerebral cortex"
• Nearly all sensory inputs pass through it to the higher levels of the brain
The Forebrain:
Basal Ganglia
The Limbic System
The Neocortex
Basal Ganglia
• Involved in movement
• Collection of nuclei:
- Putamen
- Globus Pallidus
- Caudate Nucleus
• Supports stimulus-response learning
• Sequencing movements
• Diseases of the BG
- Huntington's chorea: progressive cell death in BG > involuntary "dance like" movements
- Parkinson's Disease: projections in the BG die > rigidity, tremors, difficulty with balance
- Tourette's Syndrome: involuntary motorized tics and vocalizations
Basal Ganglia & Learning
• Supports stimulus-response or habit learning
• Birds ex.: brightly colored butterfly has a bitter taste, so can learn the assoc. between color and taste and refrain from eating
• Flicking a light switch, turning a handle on a door
• Basal Ganglia disorders > difficulty with these stimulus-response actions
Limbic System Structures
• Hippocampus
• Amygdala
• Septum
• As a system, involved in emoptional and sexual bx, memory, motivation and reward, navigation
Hippocampus
Mediates memory and spacial navigation
Vulnerable to effects of stress
Amygdala
Memory, emotional reactions (emotional center of the brain), species typical bx
Septum
Emotional and species typical bx
The Cerebrum: Neocortex
• The cerebrum's surface
• The neocortex is convoluted into hundreds of folds.
• Where all the higher brain functions take place
The Neocortex: cerebral cortex
Part 1
• Thin layer of cells about 1.5 to 4 mm thick
• Provides the connections and pathways for highest cog. functions such as language and abstract thinking
• Contains about 25 billion neurons, 62K mi of axons, etc...
The Neocortex: cerebral cortex
Part 2
• Has expanded the most during evolution
• Comprises 80% of the human brain
• 2500sq/cm; 1.5 to 4 mm thick
• Six layers
• Two hemispheres, four lobes
• Primary function is to create and respond to perceptions of the world
Fissure
A cleft in the cortex that is deep enough to indent the ventricles
Sulci
A shallow cleft in the cortex
Gyri
A ridge in the cortex