Autonomic Nervous System and Central Nervous System
Types of Receptors involved with autonomics
*General Acetylcholine-nicotinic 1 receptors and nicotinic 2 receptors *Sympathetic-norepinephrine(adrenergic) *parasympathetic-acetylcholine(cholinergic)
Cerebral Spinal fluid
-Fills the ventricular system -CSF is colorless, consistes of water and traces of protein and sugar -Actively secreted by capillaries which lines the ventricles
Thalamus
-Located below corpus callosum Functions of thalamus -Relay of sensory input other than olfactory -crude identification of some stimuli without pain
Functions of basal ganglia
-Motor control initiates slow smooth movement -substantia nigra originate in brain stem and synapse on basal ganglia which releases dopamine
Spinal cord
-Point of exit for 31 pair of spinal peripheral nerves -Transport of information to brain centers -Transports information to the periphery from brain -Some afferent info. can lead to direct activation of an efferent neuron and stimulation of an effector
Crossing over
-Some nerves cross in the medulla allowing cerebrum to have control of motor activities of opposite side of body -Fiber tracts that are found in the spinal cord are 2 types: descending which don't synapse and ascending which synapse once or twice
Hypothalamus
-Tightly packed nuclei below the thalamus Functions of hypothalamus -Regulate body temp. -control fullness/hunger -metabolism -emotional expression
sympathetic-thoracolumbar
-action functions -uses norepinephrine as its primary neurotransmitter
Functions of parasympathetic nervous system
-coordinate more vegetative activities like digestion with each organ -dominant controller of visceral effectors -acetylcholine tends to slow the heart beat, promotes digestion and elimination
Functions of Reticular Formation
-essential for initiating waking cycle, alertness, consciousness and initiating sleep cycle
Functions of Cerebellum
-planning of movement-posture control -equilibrium control limb movement control -helps integrate voluntary muscle movement or coordination
Sympathetic Innervation of different organs
-preganglionic neurons, splanchnic nerves -postganglionic neurons go out to the head neck, skin and sweat glands, blood vessels
Storage and release of acetylcholine
-stored in vesicles until release -100 or more vesicles can be released in a latent period of .75milliseconds
efferents
-usually dealing with internal organs - types of muscles innervated are smooth(gut) and cardiac(heart)
parasympathetic-craniosacral
-vegetative function -uses acetylcholine as its primary neurotransmitter
Peripheral nervous system
2 functional branches somatic nervous system and autonomic nervous system
Skull
2 major functions -protect and support the brain -isolate cerebral blood vessels from extracranial variations in pressure
Meninges
3 layers: *Dura mater-next to bone, thickest layer *Arachnoid-middle layer, thinner, web-like layer *pia matter-next to nervous tissue, thinnest layer
Synthesis and breakdown of acetycholine
Choline acetyltransferase-synthesizes acetycholine Acetylcholinesterase- destructs acertylcholine
4 major lobes of cerebral cortex
Frontal-anterior portion of each hemisphere Parietal-posterior to the frontal lobe Temporal- far side lobe of each hemisphere Occipital- most posterior portion of the hemispheres
Parkinson's disease
Idiopathic disease involves degeneration of neurons od Substantia nigra -leads to less dopamine release -leads to extreme difficulty in initiating movement -leads to unemotional face
Fine motor control
Left hemisphere controls right side -80% of individuals have left hemisphere dominance, right handedness -10% of individuals have right hemisphere, left handedness -10% are ambidextrous, equal control
Muscarinic acetylcholine receptors
M1-forebrain M2-heart M3-smooth muscle and exocrine glands M4-neostriatum,spinal cord and is involved in pain M5-brain ad involved in dopamine release
Drugs and Poisons used
Nicotine-poison found in tabacco Warfarin Pilocarpine-used for muscles after surgery
2 Layers of support for the Central Nervous System
Outer bony layer -skull or cranium -vertebral column -intervertebral discs Membrane layer -Dura mater -Arachnoid -Pia mater
Autonomic nervous system
Regulates bodily functions and the functions of internal organs
2 types of autonomic nervous system
Sympathetic and parasympathetic
Types of Receptors
a1-located on post synaptic cells a2-located on presynaptic terminals B2-activated by circulating hormones
Parasympathetic stimulation
activates dorsal hypothalamus, stimulates the ventral hypothalamus and brings things back closer to the middle
Termination of action-catecholamine
after its released and reacts its terminated which leads to -reuptake in nerve terminals -dilution metabolic transformation
Brain-Pons
between the midbrain and medulla and wider and thicker than medulla -consists mostly of white matter -serves as a relay center from medulla to higher brain centers
Vertebral column
bony structure that surrounds and protects the entire length of the spinal cord (consists of 26 bony structures called vertebrae)
Ventricular system
cavities in the brain that are continuous with similar cavities in the spinal cord containing cerebral spinal fluid containing -Lateral ventricles -3rd & 4th ventricle -Interventricular foreman
Stimulation of Parasympathetics
contraction of iris sphincter muscles, decrease heart rate ,secretion of fluid from bronchial glands, increase sweat gland secretions and erections
Parasympathetic Nervous system
cranial nerve fibers terminating in smooth muscles ad glands -eyes, nasal and oral cavitites, salivary glands
sacral nerve fibers(motor)
form their own nerves called pelvic splanchnic nerves
Brain-Medulla
functions as relay between the spinal cord and upper brain stem, mid brain -contains nuclei that controls the heart rate
dysmetria
inability of judgment where body is I relationship to other things in space(hand goes toward an object)
Ataxia of gait
jerky uncoordinated movements as seen in drunks
Intervertebral discs
made up of connective tissue, separate the vertebrae -tissue surrounds semifluid material - acts as "shock absorbers" keeps vertebrae from rubbing against one another
Motor Nerve FIbers-Sympathetic
nerve fibers exit the cord via ventral root then -synapse with a postganglionic neuron -pass through the chain and splanchic neve is formed
Cranial nerves
olfactory-smell optic-sight oculomotor & oculomotor- eye movement -trigeminal- face and chewing facial- face vestibulocochlear- hearing and balance glossopharyngeal-tongur and pharynx hypoglossal-tongue movements
Dominance
one hemisphere may take more control of a particular function -mechanical -artistic -mathematical -Abilities
Autonomic functions
sense of hunger/ thirst removal of waste from body regulates the body temp and blood pressure
Midbrain
smaller portion of the brainstem, on top of pons -contains 2 superior colliculi, 2 inferior colliculi and 2 cerebral peduncles
Cholinergic transmission
stimulation of postganglionic fibers of the PSNS leads to acetylcholine release at the organ and the receptors that interact are -inhibitory and excitatory receptors
sympathetic chain
sympathetic innervation takes place using a chain of ganglia and innervates most of the body
somatic nervous system
transmits conscious perceptions of environment( vision,taste, hearing, pain and temperature)
intention tremors
tremors which increase with movement(feeding oneself)
Sympathetic against stress
under stress of physical or emotional causes the "fight or flight" mechanism -faster heart rate -increase blood sugar and vasocostriction
Stimulation of SNS or adrenergic system produces:
vasoconstriction, bronchodilation, increase in heart rate and contractile force, contract sweat gland and pilomotor muscles, ejaculation
