Exam #2 Flashcards
What are the 2 divisions of the Nervous System?
The CNS & PNS
What is the CNS?
The Central Nervous System is associated with the brain & spinal cord
What is the PNS?
The Peripheral Nervous System is associated with the tissue outside the CNS
What can the PNS be divided into?
Afferent & Efferent division
What is Efferent Division?
Carries motor commands to muscles & glands
Somatic & Autonomic
Ends at the effectors
What is Afferent Division?
Brings sensory info to the CNS
Begins at the receptors
What are the cells of the Nervous System?
Neurons & Neuroglia
What are Neurons?
Nerve cells that are responsible for the transfer & processing of info in the Nervous System
What are Neuroglia?
Supporting cells that protect the neuron
What is the function of Astrocytes?
Largest & most numerous neuroglia & make up the BBB
What is the function of Oligodendrocytes?
Provide structural framework & myelinated the central nervous system (AKA form myelin sheath)
What is the function of White Matter?
Areas with mostly myelinated axons
What is the function of Gray Matter?
Composed of cell bodies & dendrites
What is the function of Microglia?
Removes bacteria thru phagocytosis (phagocytic cells)
What is the function of Ependymal Cells?
Involved in cerebrospinal fluid production & make up a cellular lining called ependyma
What is the function of Satellite Cells?
Surround cell bodies and regulate Oxygen, Carbon Dioxide, nutrient, and neurotransmitter levels
What is the function of Schwann Cells?
Surround axons and produce myelin in the PNS, also participate in repair process after injury
What are the factors that affect conduction velocity of a neuron?
Fast Impulse:
-Presence of a myelin sheath
-Myelinated axons with a large diameter
Slow Impulse:
-Lack of myelin sheath
-Unmyelinated axons with a small diameter
What are the types of Neuronal Pools?
Divergence
Convergence
Serial Processing
Parallel Processing
Reverberation
What is Divergence?
The spread of info from one neuron to several neurons
What is Convergence?
Info going from several neurons to a single neuron
What is Serial Processing?
Info going from one neuron to the next in a sequence
What is parallel processing?
Several neurons are processing the info at the same time
What is Reverberation?
Collateral axons extend back towards the origin of the impulse (on a repeater)
Which type of neuron has no distinguishable axon?
Anaxonic
Which type of neuron’s axons are not myelinated?
Bipolar
Which type of neuron is the most common type in the CNS?
Multipolar
What neurons are in dorsal roots?
Afferent axons of sensory neurons
What neurons are in ventral roots?
Efferent axons of somatic motor neurons
What plexus can the ulnar nerve be found?
Brachial plexus
What are the nerves in the Cervical Plexus?
Lesser occipital nerve
Great auricular nerve
Transverse cervical nerve
Supraclavicular nerve
Ansa cervicales nerve
Phrenic nerve
What are the nerves in the Brachial Plexus?
Dorsal scapular nerve
Suprascapular nerve
Lateral pectoral nerve
Medial pectoral nerve
Subscapular nerves
Axillary nerve
Thoracodorsal nerve
Musculocutaneous nerve
Long thoracic nerve
Medial antebrachial cutaneous nerve
Median nerve
Ulnar nerve
Radial nerve
Posterior brachial cutaneous nerve
What are the nerves in the Lumbar Plexus?
Iliohypogastric nerve
Ilio-inguinal nerve
Lateral femoral cutaneous nerve
Genitofemoral nerve
Femoral nerve
Obturator nerve
What are the nerves of the Sacral Plexus?
Superior gluteal nerve
Inferior gluteal nerve
Sciatic nerve
Posterior femoral cutaneous nerve
Pudendal nerve
What are the steps of a reflex arc?
- Activation of a sensory receptor
- Relay of info to the CNS
- Info processing
- Activation of a motor neuron
- Response by the effector
What are Development Reflexes?
Innate Reflexes & Acquired Reflexes
What are Response Reflexes?
Somatic Reflexes: Control skeletal muscle contractions
Visceral (Autonomic) Reflexes: Control actions of smooth & cardiac muscles, glands, & adipose tissue
What are Complexity of Circuit Reflexes?
Monosynaptic & Polysynaptic
What are Processing Site Reflexes?
Spinal Reflexes & Cranial Reflexes
What complexity of circuit reflexes do spinal reflexes include?
BOTH monosynaptic & polysynaptic
What are the 3 main sensory tracts?
- Posterior Column
- Spinothalamic Tract
- Spinocerebellar Tract
What sensory tracts are in the Posterior Column?
Gracile Fasciculus
Cuneate Fasciculus
Gracile Fasciculus
-Origin: Areas inferior to T6
-Destination: Cerebrum
-Ascending
-Sensory
-Dorsal
-Decussate and form medial lemniscus
Cuneate Fasciculus
-Origin: Areas superior to T6
-Destination: Cerebrum
-Ascending
-Sensory
-Dorsal
-Decussate and form medial lemniscus
What sensory tracts are in the Spinothalamic Tract?
Lateral Spinothalamic & Anterior Spinothalamic tracts
Lateral Spinothalamic Tract
-Origin: Spinal cord
-Destination: Thalamus
-Ascending
-Sensory
-Dorsal
-Pain/temp sensations
-Decussates spinal cord
Anterior Spinothalamic Tract
-Origin: Spinal cord
-Destination: Thalamus
-Ascending
-Sensory
-Dorsal
-Crude touch & pressure sensations
-Decussates spinal cord
What tracts are in the Spinocerebellar Tract?
Posterior Spinocerebellar & Anterior Spinocerebellar
Posterior Spinocerebellar Tract
-Origin: Spinal Cord
-Destination: Cerebellum
-Ascending
-Sensory
-Dorsal
-Involved in proprioception
-Info is not raised to conscious level
Anterior Spinocerebellar Tract
-Origin: Spinal Cord
-Destination: Cerebellum
-Ascending
-Sensory
-Dorsal
-Involved in proprioception
-Info is not raised to conscious level
Corticobulbar Tract
-Origin: Cerebral cortex
-Destination: Spinal cord
-Ascending
-Motor
-Ventral
-Conscious control over eye, jaw, & face muscles
-Decussate in brainstem
Lateral Corticospinal Tract
-Origin: Cerebral cortex
-Destination: Spinal cord
-Ascending
-Motor
-Ventral
-Conscious control over skeletal muscles
-Decussate in the pyramids of medulla oblongata
Anterior Corticospinal Tract
-Origin: Cerebral cortex
-Destination: Spinal cord
-Ascending
-Motor
-Ventral
-Conscious control over skeletal muscles
-Decussate at the level of lower motor neurons
Vestibulospinal Tract
-Origin: Vestibular nuclei
-Destination: Spinal cord
-Ascending
-Motor
-Ventral
-Send info from inner ear to monitor position of head, alters muscle tone and limbs for posture & balance
Tectospinal Tract
-Origin: Superior colliculus
-Destination: Spinal cord
-Ascending
-Motor
-Ventral
-Send info to the head, neck, and upper limbs in response to bright lights & sudden movements & loud noises
Medial Reticulospinal Tract
-Origin:
-Destination: Spinal cord
-Ascending
-Motor
-Ventral
-Send info to cause eye movements & activate respiratory muscles
Rubrospinal Tract
-Origin:
-Destination: Spinal cord
-Ascending
-Motor
-Ventral
-Send info to flexor & extensor muscles
What are the six parts of the brain?
Cerebrum
Diencephalon
Mesencephalon
Pons
Medulla Oblongata
Cerebellum
What is the Cerebrum?
-Conscious thought processes
-Intellectual functions
-Memory storage
-Conscious regulation of skeletal muscle contractions
-Contains sulk (grooves) & gyro (ridges)
What is the Diencephalon?
Contains:
Thalamus
-Relay & processing center for sensory info
Hypothalamus
-Centers controlling emotions, autonomic functions, and hormone production
Epithalamus
-Contains pineal gland
What is the Mesencephalon?
-Midbrain
-Processing of visual & auditory data
-Generativing reflexive somatic motor responses
-Maintaining consciousness
What is the Pons
-Relays sensory info to cerebellum & thalamus
-Subconscious somatic & visceral motor sensors
What is the Medulla Oblongata?
-Relays sensory info to thalamus and other portions of the brainstem
-Autonomic centers regulate visceral function (cardiovascular, respiratory, & digestive system activities)
What is the Cerebellum?
-Coordinates complex somatic motor patterns
-Adjusts output of other somatic motor centers in brain & spinal cord
Embryology of Brain
-CNS begins as a hollow tube
-Tube is filled with fluid
-In 4th week of development 3 primary brain vesicles form (Prosencephalon, Mesencephalon, Rhombencephalon)
-During 6th week of development prosencephalon & rhombencephalon form secondary brain vesicles
What secondary brain vesicles are formed by Prosencephalon?
Telencephalon: forms cerebrum
Diencephalon: forms epithalamus, thalamus, & hypothalamus
What secondary brain vesicles are formed by Rhombencephalon?
Metencephalon: forms cerebellum & pons
Myelencephalon: forms medulla oblongata
Ventricles 1 & 2
-Called Lateral Ventricles
-Located in cerebral hemispheres, separated by a partition called SEPTUM PELLUCIDUM
-Communicates with 3RD VENTRICLE thru INTERVENTRICULAR FORAMEN
Ventricle 3
-Located in diencephalon
-Communicates with 4TH VENTRICLE thru the CEREBRAL AQUEDUCT of the midbrain
Ventricle 4
-Lies between the pons & the cerebellum
-Communicates with the CENTRAL CANAL of the spinal cord
How does cerebrospinal fluid flow in ventricles?
-Fluid transports nutrients to the CNS & transports waste away from CNS
What is the Blood Brain Barrier?
The lining of blood vessels consist of endothelial cells that are highly interconnected by tight junctions
-Only lipid-soluble lateral can pass from the blood to the cells of brain & spinal cord
-Water-soluble material can only pass via the action of transport mechanisms
What are the 4 major regions within the brain where the BBB is different from the rest of the brain?
-Hypothalamus: increased permeability to hormones
-Capillaries in Pineal Gland: very permeable to allow pineal secretions into circulation
-Capillaries in Choroid Plexus: transport activités of ependymal cells maintain blood-CSF barrier
-Capillaries in Posterior Lobe of Pituitary Gland: permeable to hormones
What occurs in the Chorioid Plexus?
Where most of cerebrospinal fluid is made, on basal (inferior) side of lateral ventricles
What are the nuclei you would find in the Medulla Oblongata?
-Gracile nucleus & Cuneate nucleus: Somatic sensory info to Thalamus
-Solitary nucleus: Receives visceral sensation from spinal & cranial nerves
-Olivary nuclei: Pass info from cerebrum, spinal cord, diencephalon, & brainstem to cerebellum
What are the lobes of the Cerebral Cortex?
Frontal Lobe
Occipital Lobe
Temporal Lobe
Parietal Lobe
What are the lobes of the Cerebral Cortex?
-Frontal Lobe
-Occipital Lobe
-Temporal Lobe
-Parietal Lobe
What are the association areas of the Frontal Lobe?
-Primary motor cortex
-Premotor cortex
-Prefrontal cortex
What are the association areas of the Parietal Lobe?
-Primary somatosensory cortex
-Somatosensory association area
What are association areas of the Occipital Lobe?
-Visual association area
-Visual cortex
What are the association areas of the Temporal Lobe?
-Auditory association area
-Auditory cortex
-Olfactory cortex
Are preganglionic neurons in sympathetic nervous system short or long?
Short
Why sympathetic chain ganglia are cool?
Innervates more than one part of the body (global); fight or flight
What do Chromatin cells do and where are they found?
Release hormones & found in adrenal gland
What are the functions of the sympathetic nervous system?
-Active during excitation or physical activity
-Inhibit digestive organs
-Rate & force of the heart’’s contractions increase
-“Fight or flight”
What are the functions of the parasympathetic nervous system?
-Active during resting conditions
-Stimulates the digestive organs
-Inhibits cardiovascular system (decreasing heart rate)
-“Rest & digest”
What is myelin?
An insulating layer, or sheath that forms around nerves, including those in the brain and spinal cord made up of protein and FATTY substances
Why white matter is white?
White matter are areas of mostly myelinated axons (AKA a lot of FAT)
In gross direction, the film terminals and the long ventral & dorsal roots are collectively referred to as the what?
Cauda Equina (horse’s tail)
What is the subarachnoid space and where is it?
The subarachnoid space is filled with CS fluid and is below the arachnoid mater
Where is the 1st order neuron located and what does it do?
Found in the gracile fascicles of the posterior columns and synapses with the 2nd order neuron
Where is the 2nd order neuron located and what does it do?
Decussates in the medulla and forms the medial lemniscus, synapses with 3rd order neurons
Where is the 3rd order neuron located and what does it do?
Found in the Thalamus in the medial lemniscus and carries info to cerebral cortex
What are the general receptors?
-Nociceptors: pain receptors
-Thermoreceptors: respond to temp
-Mechanoreceptors: stimulated by physical distortion, contact, pressure
-Chemoreceptors: monitor chemical composition of body fluids and respond to specific molecules
