CNS-Brain Flashcards
Folds in the brain
Gyri
Grooves in the brain
Sulci
Deep groove in the brain
Called longitudinal fissure
Generalized functions of the lobes
Sensory, motor, visual, auditory, language and higher cognitive functions, memory
Thalamus
Relaying and modulating sensory input to cerebrum
-Modulating cerebral activity to regulate motor function
Hypothalamus
Homeostasis; growth and reproduction
Brainstem
Midbrain, Pons and Medulla Oblongata
-Vegetative functions such as cardio regulation, swallowing, yawning, etc.
Cerebellum
Posture, balance, and smooth coordinated movements
The Cortex Cranial Nerves
CN I - CN II
Midbrain Cranial Nerves
CN III - CN IV
Pons Cranial Nerves
CN V - CN VIII
Medulla Cranial Nerves
CN IX - XII
Inner gray matter (nuclei)
Cell bodies of neurons and glial cells
Outer white matter (tracts)
Myelinated axons, neural “highways”
Is the dorsal horn part of the sensory or motor tract?
Sensory
Is the ventral horn part of the sensory or motor tract?
Motor
Visceral afferent fibers
Nerve fibers coming from organs to the spinal cord cell body
Adrenergic, noradrenergic
A nerve ending that releases norepinephrine as the primary transmitter; also, a synapse in which norepinephrine is the primary transmitter
Adrenoceptor, adrenergic receptor
A receptor that binds, and is activated by, one of the catecholamine transmitters or hormones (norepinephrine, epinephrine, dopamine) and related drugs
Baroreceptor reflex
The homeostatic mechanism that maintains a constant mean arterial blood pressure; the sensory limb originates in the baroreceptors of the carotid sinus and aortic arch; efferent pathways run in parasympathetic and sympathetic nerves to the heart and blood vessels
Cholinergic
A nerve ending that releases acetylcholine; also, a synapse in which the primary transmitter is acetylcholine
Cholinoceptor, cholinergic receptor
A receptor that binds, and is activated by, acetylcholine and related drugs
Dopaminergic
A nerve ending that releases dopamine as the primary transmitter; also a synapse in which dopamine is the primary transmitter
Homeostatic reflex
A compensatory mechanism for maintaining a body function at a predetermined level, for example, the baroreceptor reflex for blood pressure control
Non-adrenergic, noncholinergic (NANC) system
Nerve fibers associated with autonomic nerves that release any transmitter other than norepinephrine or acetylcholine
Parasympathetic
The part of the autonomic nervous system that originates in the cranial nerves (and traditionally, the sacral part of the spinal cord); the craniosacral autonomic system
Postsynaptic receptor
A receptor located on the distal side of a synapse, for example, on a postganglionic neuron or an autonomic effector cell
Presynaptic receptor
A receptor located on the nerve ending from which the transmitter is released into the synapse; modulates the release of transmitter
Sympathetic
The part of the autonomic nervous system that originates in the thoracic and lumbar parts of the spinal cord; the thoracolumbar autonomic system
Pheochromocytoma
-Most common tumor of the adrenal medulla in adults
-Derived from chromaffin cells
-Secrete epinephrine, norepinephrine, and dopamine
-Symptoms: occurs in “spells”-relapse and remit
-Elevated blood pressure
-Headache
-Excessive sweating
-Palpitations (tachycardia)
-Pallor
Lab: elevated catecholamines and their metabolites metanephrine
Treatment: Surgery
Pre-Op: Phenoxybenzamine + Beta-Blocker
Multipolar
Have several dendrites and one axon
Pseudounipolar (unipolar)
One continuous process (axon) that emerges from the cell and divides into two processes
Bipolar
Have one main dendrite and one axon
Motor-Efferent
-Conveys impulses to effector cells
-Somatic: skeletal muscles
-Visceral: smooth cardiac muscles, glands found in organs
-Typically multipolar
Sensory-Afferent
Conveys impulses from receptors for integration
-Somatic: pain, temp, touch, pressure. proprioception
-Visceral: distention, ischemia, inflammation, physiological processes from internal organs, glands, blood vessels
-Typically pseudounipolar or biopolar
Interneurons (integrative)
-Communication and integration between sensory and motor neurons, tendon reflexes
Neuroglial cells
Make up about half the volume of CNS
CNS cells
Astrocytes
Oligodendrocytes
Microglia
Ependymal cells
PNS cells
Schwann cells
Satellite cells
Somatic afferent nerves run:
From skin, fascia of the body wall specifically the back and to the rest of the body
Somatic efferent nerves run:
To skeletal muscle of the deep muscles of the back, and to the rest of the muscles of the body
Visceral afferent nerves run from:
Organs
Visceral efferent (ANS) run:
To smooth and cardiac muscle, glands
Acetylcholine
-Neuromuscular junction SNS
-ANS-pre and postsynaptic neurons
-Used by cholinergic neurons
-Degraded by acetylcholinesterase
Catecolamines
-Precursor Tyrosine
-Epinephrine (Adrenaline)-used by adrenergic neurons
-Norepinephrine
-Used by catecolaminergic neruons in CNS & ENS
-Removed by COMT, MAO
Serotonin
-Precursor-Tryptophan
-Used by serotonergic neurons
Amino Acids
GABA
GLY (inhibitor)
GLU (excitatory)
ASP
*Neurotransmitters
Nitric Oxide
Synthesized within synapse
*Neurotransmitters
Small Peptides
Substance P, VIP, CCK, HRH produces by APUD cells
The Visceral system innervates [ ] target tissues:
3 target tissues:
1) Smooth muscle (GI tract, blood vessels)
2) Cardiac muscle (including conduction tissue0
3) Glands (Salivary, lacrimal)
Sympathetic Nervous System
-Fight or flight
-Catabolic system
-Increased arterial pressure
-Increased heart rate, force of cardiac contraction and cardiac output
-Increased blood flow away from skin to skeletal muscle-cold, sweaty skin (constrict vessels to skin and gut/dilate vessels to heart, muscles, lungs)
-Increased ventilation-dilation on airways-deep & rapid breathing
-Pupillary dilation (greater field of vision)
-Sweat glands
Parasympathetic nervous system
-Rest and digest mode
-Homeostatic or anabolic system
-Decreased BP
-Decreased HR
-Constrictor of bronchial tree and decreased respiratory rates
-Stimulation of gut activities-allows for digestion and waste removal
-Warm skin
-Pupillary constrictor
Axonal Transport
Bidirectional movement of material between the cell body and processes
Anterograde
Kinesin motor protein: slow or fast (towards synapse, flow of synaptic vesicles, mitochondria)
Retrograde
Dynein: motor protein involved-Fast (towards CB; recycled membrane vesicles, neuromodulators, etc.)
Neuroglia or glia cells
Non-neuronal cells that support, insulate or nourish neurons (CNS and PNS)
Peripheral neuroglia
Schwann cells and Satellite cells
Central neuroglia
Astrocytes, oligodendrocytes, ependymal cells and microglia cells
Protoplasmic astrocytes
Prevalent in the gray matter
-Branching cytoplasmic processes
-Maintain the blood-CSF barrier
-Contains GFAP (protein of the intermediate filament family) helps provide structural support/strength to cells
Fibrous astrocytes
-Prevalent in white matter
-Has straight cytoplasmic processes, contains GFAP
Microglia
-Smallest type
-Originate from hematopoietic (blood cell) line
-Functions in phagocytosis of bacteria, removal of debris & injured tissue
-Has abundant spikes/ruffled border of cytoplasmic processes
Oligodendrocytes
Myelinate axons in the CNS
-Have tongue-like cytoplasmic processes
-Larger nodes of Ranvier (NR)-increases efficiency of nerve conduction
-One oligodendrocyte myelinates portions of several axons
Ependymal cells
Epithelium lining of the CNS cavities
-Cuboid to columnar cell type
-Have characteristic of fluid transporting/absorbing cells (cilia, microvilli, basal infoldings)
-Found in choroid plexus, modified cells that interact with capillaries and help secrete cerebrospinal fluid (CSF)
Schwann cells
Myelinate neurons in PNS. Several Schwann cells myelinate portions of one axon. Provide support for both myelinated and unmyelinated axons in PNS.
-Clean up debris
-Scaffolding for regeneration of nerve tissue
Satellite cells
-Small cuboidal cells
-Surround the cell body of neurons in PNS
-Regulate the perineuronal environment
-Electrical insulator, does not make myelin
-Regulate metabolic exchange
Myelin
-Lipid rich layer deposited around the axons of neurons
-Formed by the mesoaxon of the Schwann cells
-Serves to insulate/support axons of nerves fibers from the environment surrounding the endoneurium
-Facilitates rapid conduction of nerve impulses
Schwann Cells
Myelinate neurons in PNS. Several Schwann cells myelinate proportions of one axon. Provide support for both myelinated and unmyelinated axons in PNS
-Clean up debris
-Scaffolding for regeneration of nerve tissue
Satellite cells
Small cuboidal cells
-Surround the cell body of neurons in PNS
-Regulated the perineuronal environment
-Electrical insulator, does not make myelin
-Regulate metabolic exchange
Dura mater
Outer covering
-Dense connective tissue
-Vascular
-In the cranium forms the dural venous sinuses
-Innervated
Arachnoid mater
Loose connective tissue
-Lined back to back by simple squamous epithelium
-Projects into the sinus to drain CSF into the blood stream
-Avascular
Pia mater
-Vascular loose connective tissue
-Lies directly on brain and spinal cord
-Interact with ependymal cells to form choroid plexus
