Spinal Cord, ANS, CNS, Neurons Flashcards
What do B nerve fibers do?
- Small
- Myelinated
- Conduct less rapidly than A
- Preganglionic autonomic
What is a chemical synapse?
Chemical neurotransmitters are released
What is the dura mater and where is it located?
- Outer, tough, fibrous membrane
- Attached to inner surface of cranium
- Forms falx and tentorium
What does a neurons axon do?
- One-way conduction
- Conducts impulses away from the cell body
What pathways are in the descending fiber system?
Motor pathways
What pathways are in the ascending fiber system?
Sensory pathways
What do the Corticospinal Tracts do?
- Voluntary muscle control
(descending - motor pathway)
What are the 4 types of A nerve fibers?
- Alpha
- Beta
- Gamma
- Delta
What does cerebrospinal fluid (CSF) do?
- Mechanical support (cushions brain)
- Controls brain excitability by regulating ionic composition
- Aids in exchange of nutrients and waste
What do projection neurons do?
Carry impulses to other parts of the CNS
What structures make up venous drainage from the head and neck?
- Cerebral Veins
- Dural venous sinuses
What signals do Beta nerve fibers send?
- Touch
- Pressure
(A fiber type)
What signals do Gamma nerve fibers send?
- Motor to muscle spindles
(A fiber type)
The vertebral arteries join to form what artery in the brain?
- Vertebral arteries arise off the subclavian arteries and unite to form the basilar artery
- Bifurcates into two posterior cerebral arteries
What does the Autonomic Nervous System (ANS) do?
Innervations of involuntary structures:
- Smooth muscle
- Heart
- Glands
Helps maintain homeostasis
The vertebral arteries supply what parts of the brain?
- Brainstem
- Occipital lobes
- Cerebellum
- Parts of Thalamus
What do the Spinorericular Tracts do?
- Deep and Chronic Pain
(ascending - sensory pathway)
What are the ventricles in the brain for?
How many are there?
- Filled with CSF and communicate with each other and with the spinal cord
- 4 ventricles or cavities
What do the Tectospinal Tracts do?
- Assists in head-turning responses to visual stimuli
What do the Spinocerebellar Tracts do?
- Proprioception from muscle spindles, golgi tendon organs, and touch and pressure receptors to cerebellum for control of voluntary movements
(ascending - sensory pathway)
What is the subarachnoid space and where is it located?
- Contains cerebrospinal fluid (CSF) and cistern (major arteries)
- Between arachnoid and pia mater
What signals do Alpha nerve fibers send?
- Proprioception
- Somatic Motor
(A fiber type)
What do the Rubrospinal Tracts do?
- Assist in Motor Function
What is a neuron cell body?
Genetic center with dendrites to receive information
What do you call groups of nerve cell bodies?
Nuclei
(In the peripheral nervous system, they are ganglia)
What does the Parasympathetic Nervous System (PNS) do?
Craniosacral Division: CN III, VII, IX, X, pelvic nerves
- Conserve and restore homeostasis
- Decrease HR & BP
- Increase peristalsis & glandular activity
What do the Spinothalamic Tracts do?
- Pain
- Temperature
- Crude Touch
(ascending - sensory pathway)
What do C nerve fibers do?
- Smallest
- Unmyelinated
- Slowest conducting
What does the Sympathetic Nervous System (SNS) do?
Thoracolumbar Division T1-L2
- Fight or flight
- Emergency response
- Increase HR & BP
- Constricts peripheral blood vessels
- Inhibits peristalsis
What is the blood-brain barrier?
Selective restriction of blood-borne substances from entering the CNS.
What do the Vestibulospinal Tracts do?
- Lateral (uncrosses) and Medial (crossed)
- Control muscle tone, antigravity muscles, and postural reflexes
What spinal tracts run in the ascending fiber system?
- Dorsal Column/Medial Lemniscal System
- Spinothalamic Tracts
- Spinocerebellar Tracts
- Spinoreticular Tracts
What do neuroglia do?
- Support cells that do not transmit signals
- Important for myelin and neuron production
- Maintenance of K+ levels & reuptake of neurotransmitters after neural transmission at synapses
What arteries form the Circle of Willis?
- Anterior communicating artery connecting the 2 anterior cerebral arteries
- Posterior communicating artery connecting each posterior and middle cerebral artery
The carotid arteries supply blood to what part(s) of the brain?
Supplies large area of brain and many deep structures
What signals do Delta nerve fibers send?
- Pain
- Temperature
- Touch
(A fiber type)
What do the lateral ventricles do?
- Communicates with third ventricle through foramen of Monro
- One in each hemisphere
What does the Dorsal Columns/Medial Lemniscal system do?
- Proprioception
- Vibration
- Tactile Discrimination
(ascending - sensory pathway)
What does the fourth ventricle do?
- Foramina of Luschka and Magendie communicate with fourth ventricle through subarachnoid space
- Located in pons and medulla
What are meninges?
the 3 membrane layers that surround the brain
The carotid arteries branch into what main arteries of the brain?
Internal carotid arteries arise off common carotids and branch to form middle and anterior cerebral arteries
What do the Reticulospinal Tracts do?
- Dorsal Gray: modifies transmission of sensation; especially pain)
- Ventral Gray: influences gamma motor neurons and spinal reflexes
What spinal tracts run in the descending fiber system?
- Corticospinal Tracts
- Vestibulospinal Tracts
- Rubrospinal Tracts
- Reticulospinal System
- Tectospinal Tract
What does the third ventricle do?
- Communicates with fourth ventricle through cerebral aqueduct
- Posterior and deep to lateral ventricles
What is the pia mater and where is it located?
- Innermost layer
- Delicate
- Covers the brain’s surface and follows its contours.
What do Interneurons do?
Short relay neurons
What is an electrical synapse?
Electrical signals pass directly from cell to cell
What structures make up a neuron?
- Cell bodies
- Axons
- Synapses
What are A nerve fibers?
Large, myelinated, fast-conducting
What is the arachnoid mater and where is it located?
- Delicate, vascular membrane (“spider web”)
- subdural spaces lies between dura mater and arachnoid mater
- subarachnoid space lies deep between arachnoid mater and pia mater
What do synapses do?
Communicate between neurons
What are the 2 divisions of the ANS?
- Sympathetic
- Thoracolumbar division: T1-L2
- Parasympathetic
- Craniosacral division: CN III, VII, IX, X, pelvic nerves
