Nervous System Flashcards
Basic functions of the nervous system
- Sensation
- Integration
- Reaction
3 kinds of neurons that connect CNS to the body
- sensory
- Motor
- interneurons
Neurons that connect CNS to muscle and organs
Motor neurons
Neurons that connect sensory receptors to CNS
Sensory neurons
Neurons that provide connections within CNS
Interneurons
2 big initial divisions of the nervous system
- Peripheral Nervous System
- Central Nervous System
A division of the nervous system composed of everything outside of the brain and spinal cord; carries out information to and from the brain
Peripheral Nervous System
A division of the nervous system composed of the brain and spinal cord; the center of integration and control
Central Nervous System
The two divisions of Peripheral Nervous System
- Sensory Division (Afferent)
- Motor Division (Efferent)
Functions of the Sensory Division
- Conducts impulses from receptors to the CNS
- Informs CNS of the state of the body (interior and exterior)
Function of the Motor Division
Conducts impulses from CNS to effectors (muscles/glands)
The Motor (Efferent) Division is divided into:
- Somatic (skeletal) nervous system
- Autonomic nervous system
- Involved in voluntary movement
- Conduct impulses from the CNS to skeletal muscles
Somatic (skeletal) nervous system
- Involved in involuntary movement
- Conduct impulses from the CNS to smooth muscle, cardiac muscle, and glands
Autonomic nervous system
Sensory nerve fibers in the sensory division
- Somatic
- Visceral
The Autonomic Nervous System is divided into:
- Sympathetic Nervous System
- Parasympathetic Nervous System
The sympathetic and parasympathetic systems are ________ .
Antagonistic
Functions of the Autonomic Nervous System
- Controls involuntary functions: heartbeat, blood pressure, respiration, perspiration, and digestion
- Can be influenced by thought and emotions via the hypothalamus
Also known as the “Rest and Digest” System
Parasympathetic Nervous System
Responsible for the “Fight or Flight” response
Sympathetic Nervous System
Functions of the Parasympathetic Nervous System
- Calms the body to conserve and maintain energy
- Lowers heartbeat, breathing rate, and blood pressure
Functions of the Sympathetic Nervous System
- Releases adrenaline and noradrenaline
- Increases heart rate and blood pressure.
- Increases blood flow to skeletal muscles.
- Inhibits digestive functions.
The nervous tissue is highly _____ .
Cellular
Two cell types in Nervous Tissue
- Neurons
- Neuroglia
Function of Neurons or Nerve cells
Receive stimuli and transmit action potentials
Function of Neuroglia or Glial cells
Support and protect neurons
Four types of Neuroglia found in the CNS
- Astrocytes
- Oligodendrocytes
- Ependymal Cells
- Microglia
Two types of Neuroglia found in the PNS
- Satellite Cells
- Schwann Cells
a) Star-shaped, abundant, and versatile.
b) Guide the migration of developing neurons.
c) Involved in the formation of the blood-brain barrier.
d) Function in nutrient transfer.
Astrocytes
Produce the myelin sheath which provides electrical insulation for certain neurons in the CNS.
Oligodendrocytes
Line brain ventricles and spinal cord central canal; help form choroid plexuses that secrete Cerebral Spinal Fluid (CSF).
Ependymal Cells
Specialized macrophages
Microglia
Surround clusters of neuronal cell bodies in the PNS; function unknown
Satellite Cells
Form myelin sheaths around the larger nerve fibers in the PNS; vital to neuronal regeneration
Schwann Cells
Myelin is made by ______ in the brain and spinal cord and by ______ in the peripheral nervous system.
- Oligodendrocytes
- Schwann Cells
Gaps in the myelin sheath that contain many Na+ channels
Nodes of Ranvier
When action potentials “jump” from one node to the next, increasing conduction speed 50-100x.
Saltatory Conduction
Ions that have higher concentrations inside the cell
Potassium Ions (K+)
Ions that have higher concentration outside the cell
Sodium Ions (Na+)
The typical membrane potential for cells
Resting Potential
Changes in permeability are due to changing the number of _______ .
open membrane channels
Always open and specific for a particular ion.
Non-gated ion channels (leak channels)
Open only under specific conditions (stimulus): voltage-gated, ligand-gated, stress-gated
Gated Ion Channels
Active (require ATP) and maintain ion gradients
Ion Pumps
- Small, localized change in membrane potential (a few mV)
- Travel only a short distance (a few mm).
Graded Potentials
Where does graded potentials occur?
Dendrites and cell body
- Brief, rapid reversal of membrane potential (large change of ~70-100 mV).
- Self-propagating; signal strength is maintained.
- Long-distance transmission
Action Potentials
When a cell is exposed to a chemical signal for a prolonged period, it ________ .
loses sensitivity
A neuromodulator (prolongs signal transmission across the synapse) that causes large amounts of neurotransmitters to remain in synapses for extended periods.
Cocaine
The brain and spinal cord consists of:
- White matter
- Gray matter
Are bundles of myelinated axons
White matter
Are masses of cell bodies and dendrites covered with synapses
Gray matter
In the spinal cord, white matter is on the ______ and gray matter is ______ .
- surface
- inside
Conducts sensory information from the peripheral nervous system (both somatic and autonomic) to the brain.
Spinal cord
- Actions that result from a nerve impulse passing over a reflex arc.
- Predictable response to a stimulus.
Reflex Actions
Somatic Reflexes that have Clinical Importance
- Knee Jerk Reflex
- Ankle Jerk Reflex
- Babinski Reflex
- Plantar Reflex
- Corneal Reflex
- Abdominal Reflex
The extension of the foot in response to tapping the Achilles tendon.
Ankle Jerk Reflex (Achilles Reflex)
Extension of the great toe in response to stimulation of the outer margin of the sole of the foot; present in infants up to 1 1/2 years old.
Babinski Reflex
Plantar flexion of all toes and slight turning in and flexion of the anterior part of the foot in response to stimulation of the outer edge of the sole.
Plantar reflex
Winking in response to touching the cornea
Corneal reflex
Drawing in of the abdominal wall in response to stroking the side of the abdomen.
Abdominal Reflex
Extension of the lower leg in response to tapping the patellar tendon with a reflex hammer.
Knee Jerk Reflex
Parts of the brain stem
- Medulla oblongata
- Midbrain
- Pons
What vital centers are located in the medulla oblongata?
- Cardiac
- vasomotor
- respiratory centers
What non-vital reflexes are controlled by the medulla oblongata?
- Vomiting
- coughing
- sneezing
- hiccupping
- swallowing.
What type of receptors in the medulla oblongata are targeted by opiates?
Mu (µ) receptors, which explain opiates’ suppressive effect on breathing.
How does the medulla oblongata regulate breathing?
It sends rhythmic nerve impulses to the intercostal muscles and diaphragm.
How does the medulla oblongata affect blood flow?
It regulates the diameter of arterioles, adjusting blood flow.
What is the main function of the midbrain?
It acts as a relay station for auditory and visual information.
Which structures in the midbrain are involved in controlling body movement?
red nucleus and substantia nigra
What condition is associated with the degeneration of neurons in the substantia nigra?
Parkinson’s disease
What does the word “pons” mean in Latin?
Bridge
What role does the pons play in sleep?
contains the sleep paralysis center and helps generate dreams.
What respiratory function is associated with the pons?
Contains pneumotaxic centers that aid in respiration
How does the pons serve as a relay station?
It carries signals from the cerebral cortex to the cerebellum
What are the primary functions of the cerebellum?
- motor skills
- posture
- maintaining equilibrium.
What happens to muscle movements in individuals with cerebellar damage?
Their muscle contractions become jerky and uncoordinated.
The chief sensory integrating center
Thalamus
Which sensory input does NOT pass through the thalamus?
Olfaction (sense of smell)
The regulator/coordinator of autonomic activities
Hypothalamus
How does the hypothalamus interact with the posterior pituitary gland?
Sends vasopressin and oxytocin to the posterior pituitary, which then releases them into the blood.
Functions that hypothalamus regulate
- Water balance
- Body temperature
- Feeding and satiety
The “executive suite” of the nervous system
cerebral hemisphere
How does the surface area of the cerebral hemispheres increase?
Convolutions (folds) triple its surface area
Is made up of a pair of large cerebral hemispheres.
Prosencephalon (Forebrain)
What percentage of the brain’s mass do the cerebral hemispheres account for?
40%
What are the sensory functions of the cerebral hemispheres?
- Somatic senses: Touch, pressure, temperature, proprioception.
- Special senses: Vision, hearing, olfaction, taste.
What are the motor functions of the cerebral hemispheres?
- Primary motor cortex
- Premotor cortex
- Broca’s area
- Frontal eye field
What integrative functions are managed by the cerebral hemispheres?
- Consciousness
- Language
- Emotions
- Memory
Regions of the cerebral cortex that communicate with primary sensory areas and the motor cortex to analyze, recognize, and act on sensory input.
Association areas
What is the most complicated region of the brain?
Pre-frontal area
What functions are associated with the pre-frontal area?
- Intellect
- cognition
- personality
- abstract ideas
- judgment
- reason
- persistence
- planning
- concern for others
- conscience
What kind of feedback influences the pre-frontal area?
Positive and negative feedback from the social environment
What condition causes mental/personality disorders, wide mood swings, loss of attentiveness and inhibition?
Tumors in the Pre-frontal Cortex (PFC)
Which association area integrates sensory inputs into a single thought?
General interpretation (gnostic) area
Two language areas in the brain.
- Wernicke’s Area
- Affective Language Areas
Language area of the brain involved in sounding out unfamiliar words.
Wernicke’s Area
Language area of the brain involved in non-verbal/emotional components of language
Affective language areas
A condition where speech lacks emotional expression and is flat.
Aprosodia
What concept refers to the specialization of cerebral hemispheres?
Split-brain concept or division of labor
The dominant hemisphere for language, math, and logic
Left Hemisphere
The hemisphere dominant for visual/spatial skills, intuition, emotion, and art appreciation
Right Hemisphere
What percentage of individuals are left-hemisphere dominant?
90%
What is the term for individuals who share functions equally between hemispheres?
Ambidexterity
What condition is associated with a lack of cerebral dominance?
Dyslexia
Obstruction in the drainage of cerebrospinal fluid (CSF)
Hydrocephalus
What is the cure for hydrocephalus?
Implantation of a shunt (tube) to drain excess fluid
Epilepsy is characterized by _______ .
Seizures
What causes seizures in epilepsy?
Sudden abnormal bursts of neuron activity
A condition where nervous tissue is replaced by connective tissue, forming hardened patches throughout the CNS.
Multiple sclerosis
A degenerative disease characterized by plaque formation in synaptic vesicles
Alzheimer’s Disease
Symptoms of Alzheimer’s disease
- Extreme forgetfulness
- Mood swings
- Dementia
Corrosion of the myelin sheath; a sex-linked sensory-neural disorder causing irreparable damage
Adrenoleukodystrophy
The possible causes of cerebral palsy:
- Mechanical trauma to the head
- Nerve-damaging poisons
- Prenatal infections of the mother
- Reduced oxygen supply to the brain during delivery
Permanent damage to the motor areas of the brain
Cerebral palsy
Oxygen supply to the brain is disrupted, neurons die, and the opposite side of the body is paralyzed (hemiplegia).
Stroke or Cerebrovascular Accident (CVA)
What causes a cerebrovascular accident (CVA, stroke)?
Hemorrhage or blockage of cerebral blood vessels
