front 1 Somatic vs. Autonomic: (motor pathway, ganglia, afferent input) | back 1 Somatic: - single neuron from CNS to effector - No ganglia involved - Afferent origin from skeletal muscles, joints, and skin Autonomic: - Two-neuron chain: preganglionic and postganglionic - Uses ganglia (clusters of neuron cell bodies in the PNS) - Afferent input from visceral organs (digestive, cardiovascular) |
front 2 Thoracolumbar (Origin/Function) | back 2 Sympathetic Division - Origin: Preganglionic neurons in the lateral horns of spinal cord segments - Function: Activated during exertion, stress, or emergency; prepares the body for intense physical activity |
front 3 Craniosacral (Origin/Function) | back 3 Parasympathetic Division - Origin: Preganglionic neurons in the brainstream - Function: Active during relaxed states. Promotes digestion, energy conservation, and bodily maitenance |
front 4 Thoracolumbar (Sympathetic) Ganglia | back 4 Sympathetic Chain Ganglia Collateral Ganglia Adrenal Medulla |
front 5 Sympathetic Chain Ganglia | back 5 Paired and located near the spinal cord. They send messages to effectors in the thoracic cavity, head, body wall, and limbs |
front 6 Collateral Ganglia | back 6 Unpaired and located anterior to the spinal column. They run to organs in the abdominal cavity and innervate visceral effectors in the abdominal pelvic cavity |
front 7 Adrenal Medulla | back 7 Found on the kidney; instead of a direct nerve link, the adrenal medulla releases epinephrine and norepinephrine directly into the bloodstream - These circulating hormones are distributed throughout the body to target organs |
front 8 Thoracolumbar (Sympathetic) Neurotransmitters | back 8 - Preganglionic neurons release Acetylcholine (ACh) which excites the chain ganglia - Most postganglionic neurons release Norepinephrine (NE), which is usually excitatory but depends on the receptor at the target organ |
front 9 Thoracolumbar (Sympathetic) Effects on Target Organs Eye: Salivary Glands: Cardiovascular and Respiratory Systems Digestive Organs Kidney and Bladder Reproductive Organs | back 9 Eye: Causes a dilation of the pupils Salivary Glands: Mostly not excited; stimulation is more associated with parasympathetic activation Cardiovascular and Respiratory Systems: Increases heart rate and respiration Digestive Organs: Not excited or stimulated (resources are diverted away during "fight or flight" Kidney and Bladder: Activity is dampened. The detrusor muscle of the bladder is relaxed, while the sphincter is contracted to prevent the release of urine Reproductive Organs: Not in an excitatory mode |
front 10 Craniosacral (Parasympathetic) Ganglia | back 10 - The preganglionic neurons are located in the brain stem (with cranial nerves) and the sacral spinal cord. The preganglionic fibers are long because the ganglia are not adjacent to the spinal cord - The ganglia (peripheral ganglia) are located within or right adjacent to the target organs - The preganglionic neurons release acetylcholine (ACh), which is excitatory to the ganglia - The postganglionic neurons also release ACH, which will usually be inhibitory, but depends on the receptor |
front 11 Cranial Nerve Outflow Oculomotor: Facial: Glossopharyngeal: Vagus: Sacral Outflow: | back 11 Oculomotor: Innervates the levator palpebrae (lifts the eyelid) Facial: Controls tear glands and salivary glands Glossopharyngeal: Important for salivary gland innervation Vagus: Responsible for about 75% of all parasympathetic outflow, much of it related to digestive function Sacral Outflow: The preganglionic fibers form the pelvic nerves, which innervate pelvic organs |
front 12 Craniosacral (Parasympathetic) Effects on Target Organs Eyes: Digestive System: Defecation: Urination: Cardiovascular: Respiratory: Reproductive: | back 12 Eyes: Constriction of the pupils and a "drowsy" eyelid Digestive System: Secretion of digestive glands, secretion of hormones promoting nutrient absorption, and increased smooth muscle activity along the digestive tract to move matter Defecation: stimulation and coordination of defecation Urination: contraction of the urinary bladder (the detrusor muscle) and relaxation of the urinary sphincter Cardiovascular: reduction in heart rate and force of contraction Respiratory: Constriction of the respiratory passageways Reproductive: Sexual arousal |
front 13 Dual Innervation | back 13 Innervated by both the sympathetic and parasympathetic systems (most vital organs) - The two systems have opposite effects but work together to maintain homeostasis |
front 14 How does the ANS maintain Homeostasis? | back 14 Through various reflexes |
front 15 Layers protecting the brain (superficial to deep | back 15 Scalp Epicranialaponeurosis: a broad, tendon-like sheath of dense connective tissue Loose connective tissue Periosteum: the outer fibrous layer covering the cranial bones Cranium: bony skull Meninges: three protective membrane layers - Dura mater --> arachnoid mater ---(subarachnoid space containing CSF)---> pia mater |
front 16 Major Regions of the Brain | back 16 Cerebrum, Cerebellum, Diencephalon, Midbrain, Pons, medulla Oblongata |
front 17 Cerebrum | back 17 Largest part of the brain, responsible for higher functions. - Hemispheres, longitudinal fissure, contralateral control, corpus callosum, cerebral cortex |
front 18 Contralateral Control | back 18 Each cerebral hemisphere controls the opposite (contralateral) side of the body. |
front 19 Longitudinal Fissure | back 19 Separates the left and right cerebral hemispheres |
front 20 Corpus Callosum | back 20 A large bundle of white matter fibers deep within the longitudinal fissure that allows communication between the two hemispheres |
front 21 Cerebral Cortex | back 21 The outer layer of the cerebrum, composed of gray matter (contains neuronal cell bodies) - gyri = folds - sulci = grooves |
front 22 Frontal Lobe | back 22 Primary Motor Cortex (Precentral Gyrus), Premotor Cortex, Prefrontal Cortex |
front 23 Primary Motor Cortex (Precentral Gyrus) | back 23 Initiates voluntary skeletal muscle movement |
front 24 Premotor cortex | back 24 Plans and coordinates complex movements |
front 25 Prefrontal cortex | back 25 Responsible for executive functions, decision-making, and personality |
front 26 Parietal lobe | back 26 Primary Somatosensory Cortex (Postcentral Gyrus), Somatosensory Association Area |
front 27 Primary Somatosensory Cortex (Postcentral Gyrus) | back 27 Receives and processes sensory information from the body |
front 28 Somatosensory Association Area | back 28 Integrates and interprets sensory information |
front 29 Occipital Lobe | back 29 Visual Cortex, Visual Association Area |
front 30 Visual Cortex | back 30 Processes visual information received from the eyes |
front 31 Visual Association Area | back 31 Interprets visual stimuli |
front 32 Temporal Lobe | back 32 Auditory cortex, olfactory cortex, Gustatory cortex |
front 33 Association fibers | back 33 Bundles of white matter that allow different regions within the same cerebral hemisphere to communicate |
front 34 Cerebellum | back 34 Inferior to the occipital lobe; integrates sensory input from proprioceptors, the visual system, and the auditory system to fine-tune motor commands |
front 35 Diencephalon | back 35 Connects the brain stem to the cerebrum. Divided into: 1. Epithalamus 2. Thalamus 3. Hypothalamus |
front 36 Epithalamus | back 36 Contains the pineal gland: an endocrine gland that secretes melatonin |
front 37 Thalamus | back 37 Acts as the main relay station for sensory information. Nearly all input passes through the thalamus before being directed to the appropriate area of the cerebral cortex |
front 38 Hypothalamus | back 38 Master control center for the autonomic nervous system and the endocrine (hormone system); regulates the release of hormones from the pituitary gland |
front 39 The brain stem | back 39 Midbrain (Mesencephalon), Pons, Medulla Oblongata |
front 40 Mesencephalon (Midbrain) | back 40 Processes visual and auditory data and generates reflexive somatic motor responses; plays a key role in maintaining consciousness |
front 41 Pons | back 41 Acts as a relay center, passing sensory information to the cerebellum and thalamus; point of origin for several cranial nerves |
front 42 Medulla Oblongata | back 42 Contains autonomic centers that regulate functions; relay station for information traveling to the thalamus. Connects directly to the brain stem |
front 43 Basal Ganglia | back 43 Subcortical structures involved in the control of voluntary motor movements, procedural learning, and posture - substantia nigra: produces dopamine |
front 44 Limbic System | back 44 Strongly tied to the sense of smell and emotional states. Includes the hippocampus (memory formation), amygdala (emotion and memory), and parts of the thalamus and hypothalamus |
front 45 Ventricles | back 45 fluid-filled cavities in the brain -lateral ventricles, third ventricle, fourth ventricle |
front 46 Lateral Ventricles (2) | back 46 The largest, one per each cerebral hemisphere |
front 47 Third Ventricle | back 47 Narrow Cavity in the diencephalon |
front 48 Fourth Ventricle | back 48 Located between the brain stem and the cerebellum |
front 49 Choroid plexus | back 49 Network of specialized ependymal cells that line the ventricles and produce cerebrospinal fluid |
front 50 CSF Flow | back 50 Lateral ventricles ---(interventricular foramen)---> third ventricle----(cerebral aqueduct)---> fourth ventricle ----(foramina in the roof of the fourth ventricle)---> subarachnoid space |
front 51 Olfactory Cranial Nerve | back 51 Sensory; sense of smell |
front 52 Optic | back 52 Sensory; Vision |
front 53 Oculomotor | back 53 Motor: controls 4 of the 6 extracurricular eye muscles and the levator palpebrae superioris (elevates eyelid) |
front 54 Trochlear | back 54 Motor; Controls the superior oblique eye muscle (moves eye down and out) |
front 55 Trigeminal | back 55 Sensory: Sensation from the face Motor: Muscles of mastication |
front 56 Abducens | back 56 Motor: controls the lateral rectus eye muscle (abducts the eye, moves it laterally) |
front 57 Facial | back 57 Sensory: taste from the anterior 2/3 of the tongue Motor: Muscles of facial expression |
front 58 Vestibulochlear | back 58 Sensory: hearing and balance/equilibrium |
front 59 Glossopharyngeal | back 59 Sensory: taste from the posterior 1/3 of the tongue; monitors blood pressure in the carotid artery Motor: Assists in swallowing |
front 60 Vagus | back 60 The longest cranial nerve/primary nerve of the parasympathetic nervous system - Innervates visceral organs in the thorax and abdomen also important for speech and swallowing |
front 61 Accessory | back 61 Motor; innervates the sternocleidomastoid and trapezius muscles (neck and shoulders) |
front 62 Hypoglossal | back 62 Motor; innervates the intrinsic and extrinsic muscles of the tongue, controlling tongue movement for speech and swallowing |