Nervous System Unit Test Flashcards
What is the Afferent Neuron?
Neuron that carries ELECTRICAL impulses TOWARDS the CNS (Integration Center)
What is the Efferent Neuron?
Also known as Motor Neurons, they carry ELECTRICAL impulses AWAY from the CNS towards a muscle to contract
What is the Association Neuron?
Also known as Inter-neurons, these neurons RECEIVE messages from Afferent Neurons and link them to the Efferent/Motor Neurons (Located within the integration center)
What is a Neuron?
The messengers of the Nervous System, they use Electrical and Chemical (Synapse only) signals to transmit messages to and from the body. THE TYPE OF NERVE TISSUE THAT DOES NOT DIVIDE (Amitotic)
What is Neuroglia?
The supporting cells in the CNS, being lumped together. Neuroglia literally translates to “Nerve Glue”, all other parts of the nervous system that aren’t neurons
What are Neurotransmitters?
Chemical messengers (different from Neurons, being electrical messengers)
What is the CNS?
The brain and spinal cord, short for “Central Nervous System”
What is a Synapse?
Junction point between two neurons (chemical)
Define: Stimuli
Change in exterior environment that provokes a bodily response
What is Somatic Reflex?
Skeletal muscles involved in reflex movements
What is Autonomic Reflex?
Any and all other muscles besides skeletal muscles involved, happening without the use of the brain 24/7
What is the PNS?
Everything outside of the Brain and Spinal cord, short for Peripheral Nervous System
What is an Axon?
Part of a neuron that conducts and directs impulses AWAY from the cell body and OUTPUTS instructions (Efferent)
What is a Dendrite?
Part of a neuron that conducts and directs impulses TOWARDS the cell body and RECEIVES stimuli (Afferent)
What are the 4 Major regions of the brain?
- Cerebrum - Central Hemisphere
- Diencephalon - Within the Cerebrum
- Brain Stem
- Cerebellum - Mini Cerebrum
What is the Cerebrum?
The two primary and biggest sides of the brain, making a boxing glove shape when looking forward. It has a deep grove running down the middle to separate, and a wrinkled appearance, consisting of many peaks and valleys
What are Gyri?
Plural of Gyrus, elevated parts of the brain, composed of gray matter and surrounded by Sulcus (remember, Gyri are peaks, Sulci/Fissures are valleys)
What are Fissures?
Also known as “deep sulci,” these are deep “V” shaped grooves within the brain, separating the brain into lobes (remember, Fissures are valleys, Gyri are peaks)
What are Sulci?
Plural for Sulcus, shallow “U” shaped grooves within the brain, being more abundant than Fissures and surrounding Gyri (remember, Sulci are valleys, Gyri are peaks)
What are the 4 brain lobes and what do they control?
A. Occipital Lobe - Visual control area
B. Temporal Lobe - Auditory control area, above the ears
C. - Frontal Lobe - Motor control area, conscious movement of skeletal muscles
* Broca’s Area - Speech
control area found on
one hemisphere
D. Parietal Lobe - Somatic sensory area, receiving stimuli notifications from skin receptors/proprioceptors
What are additional parts of the Cerebrum to know?
- General Speech Area - Found at junction of the lobes and allows sounding words
- Gray Matter - Neuron cell bodies (surface of brain ridges)
- White Matter - Nerve fiber tracts deep in Cerebral Hemisphere (within/body of brain ridges)
- Cortex (Gray/White matter) - Where neurons are found
What are the Meninges?
The three “Maters”
- Dura Mater - “Hard Mother”, tough outermost layer, enclosing the brain and spinal cord
- Arachnoid Mater - Thin, middle layer of the CNS with web-like extensions
- Pia Mater - “Gentle Mother”, most internal layer of the Meninges, clinging to and holding the brain intact
Where does the Spinal Cord begin and extend to?
It begins at the Medulla (brain stem), and extends from the Foramen Magnum of the skull to the first or second Lumbar Vertebrae
What is the function of the Spinal Cord?
- It provides a two-way connection between the body and the brain (afferent and efferent)
- Works with the PNS, equipped with spinal nerves
How do spinal nerves work? How many are there?
Spinal nerves exit between each vertebra (31) in order to communicate with the body, making 31 total spinal nerves
They carry electrical impulses from the brain towards the skeletal muscles and organs via. spinal cord
What is the Cauda Equina?
The collection of spinal nerves at the inferior end of the spine (1st or 2nd Lumbar Vertebrae)
What is the overall layout and function of the Meninges in the Spinal Cord?
- Dura outside, Arachnoid middle, Pia inside
- Gray Mater - Darker Section (on a diagram)
- White Mater - Lighter Section (on a diagram)
- White Mater is on the outside
- White matter in the back is for sensory, in the front is for motor (Dorsal - Sensory / Ventral - Motor)
What are the forms of Paralysis? How do they occur?
- Flaccid Paralysis - Motor roots damaged (Ventral), severing connection to where they were attached
- Spastic Paralysis - Sensory roots damaged (Dorsal), reflex arc still intact, but no connection to brain, causing spasms
- Paraplegic - Occurs on middle-low spinal cord, paralyzing legs only (Para - 2 out of the 4 limbs)
- Quadriplegic - Occurs high on spinal cord, paralyzing all 4 limbs (Quad - 4 out of the 4 limbs)
How does the brain control the body?
Remember: It’s reversed - Right brain controls the left side of the body, and left brain controls the right side of the body
Some actions require both sides
What are the components (and functions of them) in the Reflex Arc?
- Receptor Region - Where stimuli is detected
- Afferent Neuron - Where signals from the receptor region travel through to the Interneuron
- Interneuron - Between the Afferent and Efferent neurons, chemically transmitting from Afferent to Efferent
- Efferent Neuron - Takes message from Interneuron to effect the muscle (effector), causing contraction
- Effector - Actual muscle that contracts in the reflex, after being effected by the Efferent Neuron
What are the Protectors of The Brain?
- The Skull: Fused cranial bones in which the brain resides
- Cerebrospinal Fluid (CSF): Fluid that forms a watery cushion to protect the brain
- Meninges - The three “maters” (Dura, Arachnoid, and Pia)
- Blood-Brain Barrier: Blood fluid system which keeps out harmful chemicals
What are the 4 brain lobes and what do they control?
A. Occipital Lobe - Visual control area
B. Temporal Lobe - Auditory control area, above the ears
C. - Frontal Lobe - Motor control area, conscious movement of skeletal muscles
* Broca’s Area - Speech
control area found on
one hemisphere
D. Parietal Lobe - Somatic sensory area, receiving stimuli notifications from skin receptors/proprioceptors
What is the function of Neurotransmitters in the Reflex Arc?
Neurotransmitters work in the Reflex Arc to carry chemical signs from one neuron to the next target cell
What are Nerve Plexuses? What do they do?
Segments of proximal nerves emerging from the spine. They serve the brain by relaying stimulation (pain, temperature, pressure, etc.)
What are the two functions of the Autonomic Nervous System? (ANS)
- Parasympathetic “Housekeeping” function: Nerves that function during normal times, conserve energy, and helps with digestion
- Sympathetic “Fight or Flight” function: Nerves that react to help the body REACT to unusual/frightening stimuli. It can speed heart rate, deliver extra oxygen, and so on
What are Parasympathetic nerves triggered by?
Parasympathetic nerves aren’t really “triggered” like somatic nerves, but autonomic. They work in digestion, defecation, and urination
What are Sympathetic nerves triggered by?
Sympathetic nerves are triggered by unusual stimuli, also known as the “E” division, triggered by exercise, embarrassment, etc.
What are the 3 Major Functions of the Brain?
- Sensory Input - The five special senses
- Integration - Brain neurons connecting with neurons in different locations, creating neural pathways
- Motor Output - Conduction of signals from the integration center to be converted into physical (motor) actions
What is the basic Structure of a Neuron?
- Axon: Oval shaped body tail of the neuron. It carries electrical impulses AWAY from the brain
- Dendrite: Branch-like “head” of the neuron. It carries electrical impulses TOWARDS the brain
- Cell Body: Core section of the neuron, located around the base of the Dendrites
- Schwann Cell: Outermost covering of the oval-shaped axons
What is the function of the Eye?
The Eye works in light refraction in order to capture light, bounce it around through its various layers, eventually hitting the retina to display vision to the brain
What are the overall Steps of Vision? (5 steps)
- Light is captured/bent by Cornea
- Passed through Aqueous Humor
- Enters through the Pupil, controlled by the Iris
- Lens directs light to Retina, and it passes through Vitreous Humor
- Finishes with hitting the Retina
What is the overall structure/composition of the Eye?
The Eye is primarily composed of many Rods and Cones, Rods picking up low energy/gray light and Cones pick up high energy/color light
How many parts of the Eye refract light? What are they?
The Eye has 4 light refactors. They are:
- The Cornea
- Aqueous Humor
- Lens
- Vitreous Humor
How exactly do Interneurons differ from sensory and motor neurons?
They differ due to their inability To generate action, simply acting as a “middleman” between sensory and motor neurons
Where do the CNS’s motor pathways end?
They end at the location of the skeletal muscles being controlled by them
What is Mechanical Protection for the Brain provided by?
The bones of the skull (The Cranium)
How exactly do the Meninges protect the brain?
They act as shock absorbers to prevent the brain from hitting against surrounding bones
What is the substance released at axonal endings of neurons?
Neurotransmitters
What is a collection of nerve cell bodies outside the CNS called?
Ganglia/Ganglion
What is the outer covering of a nerve?
Epineurium
What are the large onion-shaped receptors found in the dermis that respond to deep pressure called?
Pacinian receptors (or lamellar corpuscles)
What kind of pathways and fibers do spinal nerves have?
Both sensory and motor fibers/pathways
What are the two major functions of Neurons?
Irritability and Conductivity
Is the “Fight or Flight” bodily function somatic or autonomic?
Autonomic (and Sympathetic)
Where are the Midbrain, Pons, and Medulla Oblongata found?
The Brain Stem
Which part of the brain controls temperature, metabolism, thirst, and sex drive?
The Hypothalamus
What are the 8 basic steps of the Reflex Arc?
- Stimuli received
- Receptor captures
- Afferent Neuron sends impulse
- Impulse jumps Synapse into Integration Center
- Integration center carries impulse to Efferent Neuron
- Inter Neuron jumps Synapse to Efferent pathway
- Efferent neuron carries impulse to Motor Effector region
- Motor Effector contracts, producing a muscular reflex
Which part of the Eye has only Cones and has the sharpest vision?
The Fovea Centralis
Which part of our Ear controls our Static Equilibrium?
The Maculae
Which coating of the Eye contains dark pigment that prevents light from scattering?
The Choroid layer
Which part of the Ear contains receptors for Equilibrium?
The Inner Ear
What is the pathway of vibrations from the Ossicles to Eardrum to Oval Window? (In the Ear)
- Malleus (Hammer/Mallet)
- Incus (Anvil)
- Stapes (Stirrup)
The Malleus hits the Incus which goes to the Stapes
Which part of our Ear controls our Dynamic Equilibrium?
The Semicircular Canals
How are Spinal Roots/Nerves set up?
Dorsal Roots (Back) RECEIVE and send outside stimuli/sensory information TO the spinal cord
Ventral Roots (Front) SEND information OUT of the spinal cord for motor functions
Which region of the spine does NOT contain any nerve plexuses?
The Thoracic Region
How many spinal nerve plexuses are there? Where are they located?
There are 5 spinal nerve plexuses:
- Cervical Plexus (C1 - C5)
- Brachial Plexus (C5 - T1)
- Lumbar Plexus (L4 - L5)
- Sacral Plexus (S1 - S4)
- Coccygeal Plexus
How exactly do the Cranial Meninges protect the Brain?
They act as shock absorbers, protecting the brain from contact with surrounding bounds (the cranium)
